• TABLE OF CONTENTS
HIDE
 Title Page
 Table of Contents
 Preface
 Distillation columns
 Physical properties of a-...
 Bibliography
 Appendix
 Acknowledgement
 Biographical sketch
 Committee report














Title: Kinetics of the liquid phase thermal isomerization of alpha-pinene
CITATION PDF VIEWER THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00098045/00001
 Material Information
Title: Kinetics of the liquid phase thermal isomerization of alpha-pinene
Physical Description: 84 leaves : ; 28 cm.
Language: English
Creator: Fuguitt, Robert Eugene, 1917-
Publisher: University of Florida
Place of Publication: Gainesville Fla
Gainesville Fla
Publication Date: 1943
Copyright Date: 1943
 Subjects
Subject: Turpentine   ( lcsh )
Isomerism   ( lcsh )
Chemical kinetics   ( lcsh )
Chemistry thesis Ph. D
Dissertations, Academic -- Chemistry -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: leaves 80-83.
Additional Physical Form: Also available on World Wide Web
General Note: Manuscript copy.
General Note: Dissertation (Ph.D.) - University of Florida, 1943.
General Note: Biography.
 Record Information
Bibliographic ID: UF00098045
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000549576
oclc - 13222065
notis - ACX3870

Downloads

This item has the following downloads:

kineticsofliquid00fugurich ( PDF )


Table of Contents
    Title Page
        Page i
    Table of Contents
        Page ii
    Preface
        Page 1
    Distillation columns
        Page 2
        Page 3
        Page 4
        Page 5
        Page 5a
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Physical properties of a- and B-pinene
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
        Page 80
    Bibliography
        Page 81
        Page 82
        Page 83
    Appendix
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
        Page 106
        Page 107
    Acknowledgement
        Page 108
    Biographical sketch
        Page 109
    Committee report
        Page 110
        Page 111
Full Text









KINETICS OF THE LIQUID PHASE

THERMAL ISOMERIZATION

OF ALPHA-PINENE










By
ROBERT E. FUGUITT









A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILMlENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY









UNIVERSITY OF FLORIDA
May, 1943











Table of Contents


Page
Preface 1

Chapter 1. Distillation Columns 2

Chapter 2. Physical Properties of a-
and B-Pinene 15

Chapter 3. The Thermal Isomerization
of a-Pinene 34

Bibliography 81

Appendix 84

Acknowledgements 108

Biography 109

Committee Report 110


i5 7t b










PREFACE


Preliminary to the investigation of the kinetics of

the liquid phase thermal isomerization of a-pinene dis-

cussed in Chapter III it was necessary first, to develop

distillation columns capable of purifying the substrate

and of analyzing the reaction mixtures and second, to

purify and determine the physical constants of the a-pinene.

The construction and operation of efficient fraction-

ating columns for the purification and analysis of ter-

penes is described in Chapter I.

The physical properties of pure samples of a-pinene

are given in Chapter II. Since B-pinene occurs with

a-pinene in American gum turpentine(l) it seemed advisable

to determine, in addition, the physical properties of

pure B-pinene and of known mixtures of a- and B-pinene.


-1-











CHAPTER I. DISTILLATION COLUMNS1


Many efficient fractionating columns have been report-

ed, most of which have been designed primarily for petroleum

fractionation. Such columns are not necessarily effective

in terpene fractionation. To be satisfactory for the latter

the columns must perform effectively on viscous and semi-

viscous liquids at pressures of 10-20 mm. They must have a

low pressure drop and small operating holdup per theoretical

plate and must have a high throughput so that distillations

can be made in a short time in order to minimize thermal

reaction. In addition, for the purposes of this laboratory,

the columns must be of economical construction, readily

duplicated and must operate efficiently vhen heated by a

Nichrome-wound jacket insulated by an outer glass tube.

Several types of column construction were considered.

The cost of the Stedman and Podbelniak columns made their

extensive use impossible. The concentric glass tube column

of Selker, Burk and Lankelma(2), although having a very low

operating holdup and H.E.T.P., apparently does not have a

very high capacity and seems to require a more elaborate

system of column controls than was feasible. Single-turn

glass helices, a loose packing, vould not operate satis-

factorily for terpenos under the conditions described.


1The work discussed in this chapter was done in collaboration
with V. David Stallcup.


-2-











Preliminary experiments indicated that columns packed

with Berl saddles, Raschig rings, or the spiral screen

type of Lecky and E'.ell(3) could be economically con-

structed and easily operated with terpene mixtures.

Operation of distillation columns. The liquid to be

fractionated is placed in the distillation flask at the

bottom of the column. Heat is applied to the flask and the

liquid vaporizes into the column. If the column heat is

maintained close to the boiling temperature of the liquid

the vapor will condense and revaporize successively through-

out the column. The higher the mixture rises in the column

the richer it becomes in the more volatile component.

The vapors which reach the top of the column are con-

densed by means of a water jacketed condenser in the column

head. A thermometer registers the vapor temperature. The

condensed vapors may be returned to the column or collected

in a receiver. This is regulated by means of an outlet

stopcock. When the stopcock is completely closed, all the

liquid is returned to the column and the column then operates

under total reflux.

While operating under total reflux, if the column heats

are properly controlled for a period of one to several hours,

a given column will produce its best results. If the column

performance is to approach this maximum during a fractionation

of a liquid mixture the condensate must be collected from the


-3-










head so slowly that the equilibrium between the liquid and

vapor in the column is disturbed as slightly as possible.

The rate of collection is controlled by means of the outlet

stopcock. If this rate is slow most of the liquid will be

returned to the column throuGh a calibrated drop-counter.

The ratio of the volume of liquid returned to the column to

the volume of liquid collected is called the reflux ratio.

The higher the reflux ratio the more nearly are equilibrium

conditions maintained and the greater is the operating

efficiency of the column.

An industrial plate column contains a series of plates,

or levels. Then in operation a liquid phase is retained on

the surface of each plate. The liquid is constantly vaporiz-

ing and the vapors pass through slots into the liquid layer

on the plate above. For these columns, a perfect plate is

defined as one in which equilibrium is maintained between

the liquid and vapor phnzes(4).

Such a condition may be produced many times in a labor-

atory distillation column since the vapor condenses and re-

vaporizes successively throughout the column. The height of

a packed column equivalent to a perfect plate is such that

the vapor at the top of the height is in equilibrium with

the liquid at the bottom. This is termed the H.E.T.P. (height

equivalent to a theoretical plate) and is a measure of the

efficiency of the column packing, under a specified con-

dition of operation.


-4-









Tests and Measurements. Descriptions of the columns

and test data are recorded in Table 1, page 10.

To determine the column efficiency a mixture of n-heptane

and methyl chclohexane was refluxed in the column at atmos-

pheric pressure until equilibrium had been attained. At

this point two small samples vere taken, one from the head

and the other from the distillation flask. The refractive

indices of these samples were measured and the number of

plates were read directly from a graph (Figure 1), page 5-A.

This graph was suggested by Lecky and Evell(3) from the data

of Beatty and Calingaert(5) and Bromiley and Quiggle(6). The

relations on which it is based, and its derivation therefromg

are given by Stallcup(7a). In Table 27 (appendix) are

tabulated the experimental data from which the column

efficiencies were determined.

The operating holdup of the column is the volume of

liquid present in the column during the distillation. This

was measured by the method of Tongberg, Quiggle and Fenske(8).

In this method, a weighed amount of a non-volatile compound,

such as stearic acid, is dissolved in a weighed amount of a

volatile compound, benzene, and the mixture is refluxed in

the column under operating conditions. A sample of several

grams is taken from the distilling flask and weighed. The

benzene is removed from the sample on a steam bath and the

sample is weighed again. These two weighing are used to

calculate the relative amounts of the two compounds in the


-5-




Figure 1. Plate Determinations wvth n-Heptane-I.eth~l Cy- cohexane


Ii t _

I III

-1; -


O- .-- - -- -. -- -
-I : - /

I : ] -- r . .
... . \ -- r I- --T* -T -
r I i ..... -




Iumber,
of



- -



I I
4 --P-la-tes60--- *-' -













II
.--L


-0

Si.s9oo 1.3980 1.4060 1.4140 1.4O20






S .... X


5-A









distillation flask from which the weight of benzene re-

maining in the flask may be determined. This weight sub-

tracted from the original weight of mixture in the flask

must be the weight of benzene present in the column while

it is in operation. Conversion of this weight to volume

gives the operating holdup of the column. The data is

given in Table 28 (appendix). The large size of column 7

made the direct measurement of its operating holdup im-

practicable. Instead, a column 21 inches long of identical

construction was tested.

1. Original concentration of stearic acid: 10.2%

2. Original weight of mixture: 67.9 g.

3. Weight stearic acid = 0.102x67.9 1 6.9 g.

4. Final concentration of stearic acid: 16.8%

5. (0.168)X = 6.9 g. where X is the weight

of mixture in kettle after refluxing.

6. X = 6.9/0.168 = 41.1 g.

7. Weight benzene in column = 67.9 41.1 = 26.8 g.

8. Volume benzene in column = wt./density(0.89)=30.1 cc.

This corresponds to an operating holdup of 67 cc. of benzene

for column 7.

The operating holdup of a column is an important factor,

particularly in analytical distillations, since the column

holdup should be small with respect to the volume of the

mixture which is fractionated.


-6-









The non-drainable holdup was determined as recommended

by Ward(9) in which a known volume of benzene war poured into

the top of the column and the volume of benzene collected at

the bottom of the column during the first minute was observed.

The difference in these two volumes equals the non-drainable

holdup.

Pressure drops were measured on columns 7 and 8 by

connecting the manometer alternately to the kettle and the

head by means of a double diagonal stopcock. When measured

in this way the pressure drop in column 7 was 2 mm. at a head

reflux of 2.5 ml. per minute, distilling B-pinene at 20 im.

Column 8, when distilling B-pinene at 20 mm. pressure with a

head reflux of 0.8 ml. per minute, had a pressure drop of

2.5 mm.


Construction and Performance

Raschig rings (4x4 mm.) in column 1 gave an H.E.T.P. of

2.1 inches. This was a 120 cm. (4 foot) column of 11 rm.

(0.43 inch) inside diameter. Because of its high operating

holdup (0.5 ml./plate) this column could not be used for

analysis. Peters and Baker(lO) stated that unsatisfactory

results were obtained rhen 4x4 mm. Raschig rings were used in

an analytical column.

Berl saradles (4x4 mm.) in column 2 gave essentially the

same H.E.T.P. (2.0 inches) as the Raschig rings in a column

of the same size. However, when column 3 of 19 am. (0.75 inch)

inside diameter was filled with these Berl saddles the H.E.T.P.


-7-









decreased to 3.25 cm. (1.3 inches). This value is comparable

with the best values reported for other loose packings(ll)

with the exception of signle-turn stainless wire helices(12).

These data and previous experiments with the distilla-

tion of terpenes at 20 mm. pressure using 4x4 mm. Berl

saddles indicate that this is a satisfactory type of packing

for purification of components in the more readily separable

terpene mixtures. For some substances Berl saddles should

not be used because of the catalytic nature of their un-

glazed porcelain surface.

Spiral screen columns were made of two different sizes.

A. Laboratory columns for large quantities of material.

Four foot lengths of the following columns were made.

Column 4. H.E.T.k. 4.6 inches. Stainless steel gauze

(60x60 mesh) was used to make washers of outside diameter

(o.d.) 37 mm. (1.50 inches) and inside diameter (i.d.)

10 mm. (0.40 inch). One-eighth inch of the outer edge of

the washer was cupped at an angle of 45 degrees. A sector

of approximately 20 degrees was removed from each washer

and the washers were spot-welded together into a spiral

group of twenty-four. By joining those groups in a similar

manner, any desired length could be obtained. This spiral

was then placed on the inner glass tube. A stiff wire

spiral spacer, made of 1.8 inch iron wire, with five turns


-8-










to the inch was screwed into the gauze spiral. Long stiff

rods were welded to the ends of the spacer to permit pull-

ing as well as pushing of the screen into the glass tubing,

the i.d. of which was about 1/16 inch less than the o.d. of

the cupped spiral. At intervals during the insertion, the

exposed gauze spiral was tightened on the inner tube in order

to ensure a more uniform fit. ,TWhen the column was assembled

the spacer was removed by turning it in the proper direction.

Column 5. H.E.T.P. 2.8 inches. To make a tighter fit

the diameter of the inside tube was increased. Stainless

steel gauze washers (60x60 mesh), o.d. 37 mm. (1.50 inches),

i.d. 18 mm. (0.71 inch), were used. The column was assembled

by the same procedure as described above.

Column 6. H.E.T.P. 1.3 inches. The spiral screen pack-

ing of column 5 was removed, ground on the mandrel to the de-

sired outside diameter and inserted in a glass tube, the

inside diameter of which was about 1/8 inch smaller.

Column 7. H.E.T.P. 0.66 inch; operating holdup per plate

was 0.95 ml. Stainless steel gauze washers (50x50 mesh) were

used of o.d. 37 mm. (1.50 inches), i.d. 18 am. (0.71 inch).

The procedure for assembly of this column followed that for

column 4. However, after spot-welding together the washers

of this stiffer 50x50 mesh gauze the spiral was ground as de-

scribed for column 6 and then was placed on the inner rod and

inserted in a glass tube of the proper inside diameter. This

column is comparable to those reported by Lecky and Ewell(3).

-9-












Table 1


Columns and Test Data


Column
Packing


Inside
Diameter,
inches

0.d., Inner
Tube,
inches

Packing
Height,
inches

Total
Latest

H.E.T.P.,
inches

Operating
Holdup per
Plate, ml.

Nondrainable
Holdup, ml.


1
4x4 mm.
Raschig
rings


0.43


46



22

2.1



0.5


10


2
4x4 mm.
Berl
saddles


0.43


48



24

2.0



0.5


8


Column Number
3
4x4 mm. 50xi
Berl s<
saddles s


0.75


27



21

1.3



0.7


11


7
50 mesh
screen
piral


1.50



0.71



46



70

0.66



0.95


8
60x60 mesh
screen
spiral


0.40



0.10



46



64

0.72



0.14


28a


aNondrainable holdup,
bNondrainable holdup,


B-pinene, 40 ml.
B-pinene, 7.5 ml.


-10-


--











B. Laboratory columns for small quantities of material.

Column 8. H.E.T.P. 0.72 inch; operating holdup per

plate was 0.14 ml. The procedure in making this four foot

length of column was the same as that described for column 4

since the grinding used in columns 6 and 7 vws not necessary

for columns of small diameter. The column was made with

stainless steel gauze washers (60x60 mesh), o.d. 10 ran.

(0.40 inch), i.d. 2.5 mm (0.10 inch). The washers had a

1/16 inch cup around the outer edge. Nickel wire was used

as the inner rod and the spacer used had seven turns to the

inch.

Operation of spiral screen columns with terpenes. The

columns were thoroughly wetted down with the liquid and the

column temperature was adjusted to within 2 of the boiling

point of the more volatile component. The columns were

operated at total reflux until liquid-vapor equilibrium was

attained, at which time continuous fractionation was begun.

Column 7. Table 29 (appendix) contains the refractive

index data illustrating how this column functioned at 20 mm.

pressure on the separation of a-pinene from the B-pinene in

a commercial sample of a-pinene obtained from gum turpentine.

The column was operated with a head reflux of 2.5 ml. per

minute as measured by a calibrated drop counter. No attempt

was made to measure reflux at the bottom of the column. A

head reflux ratio of 25 to 1 was used. This column had also


-11-









been used successfully to obtain pure B-pinene from commer-

cial material.

Table 30 (appendix) gives the refractive index data of

a separation of a prepared mixture of a-pinene, camphene,

and B-pinene at 20 mm. by a 180 cm. (6 foot) length of a

column of the diameter and construction of column 7. A head

reflux ratio of 40 to 1 used during the collection of pure

a-pinene was purposely maintained throughout the transition

from a-pinene to camphene. This readily explains the gradual

shift toward camphene at the beginning of the transition and

the holdup of approximately 110 ml. In the transition from

camphene to B-pinene the head reflux ratio was increased to

60 to 1, causing a holdup of about 85 ml. which was 15 ml.

less than the operating holdup of the column. Over 100 ml.

of the camphene obtained had a solidifying range of 44-450C.

and the remainder solidified at temperatures not lower than

250 C. This distillation of about 800 ml. of mixture was

completed in 9 days. This indicates how this column might

be used for rapid analysis of large quantities.

Column 8. As a preliminary test this column was used

to separate a mixture of 35 ml. of carbon tetrachloride and

35 ml. of cyclohexane into approximately 90 mole percent car-

bon tetrachloride and 100 mole percent cyclohexane. The hold-

up of the column under the conditions of operation was 13 ml.

and the separation required 36 hours. The boiling point and

refractive index data is given in Table 31 (appendix).


-12-











When fractionating terpenos, column 8 was so regulated

that the head reflux was about 0.8 ml. per minute. A head

reflux ratio of 25 to 1 was used on the plateaus of the dis-

tillation curven(7b) but usually a hiGher ratio of about 40

to 1 was used when passing between plateaus. The low pres-

sure drop of this column combined with its high capacity min-

imizes any thermal reaction by allowing an analysis to be

completed in a short period of time.

32 ml. were collected from a mixture of a-pinone and

B-pincne distilled through column 8 at 20 mm. pressure.

These compounds boil 7.5 degrees apart at 20 mm. The data is

given in Table 32. 16 ml. of a-pincne, 11 ml. of B-pinene

and 5 ml. of mixture boiling between the two pure components

were obtained.

Table 33 (appendix) gives data for the separation of a

mixture of a-pinene and a dipentene cut of commercial ma-

terial. The two major fractions vere, respectively, a-pinene

and dipentene. The small middle fraction on analysis was

found to be p-menthane, which the temperature plot fails to

detect.

The data for the separation of a mixture of terpcne

alcohols at 20 mm. pressure is given in Table 34 (appendix).

Prior to distillation the mixture had a relative viscosity

of 31. The operation of the column for a material of this


-13-









viscosity is nearly as easy as it is for a mixture of a- and

B-pinene. This ease of operation with such viscous materials

makes the spiral screen type of column particularly valuable

in the analysis of many terpene mixtures.


Costs of spiral screen columns

The entire cost of column 7, including all jackets and

glass standard taper joints was $37.00; of column 8, $35.00.

Labor costs including overhead were calculated at the rate of

$1.50 per hour. Two work-hours per foot on column 7 and four

work-hours per foot on column 8 were required. These costs

do not include the construction of the punches for cutting

the spirals which requires about 15 hours each.

Summary

The details of the construction of the spiral screen type

of column are given.

Test data for 4x4 mm. Raschig rings, 4x4 nm. Berl saddles,

and the spiral screen columns are given. For a loose packing

the 4x4 mm. Berl saddles have a high efficiency and are suit-

able for terpene fractionations.

Results are given for the operation of columns with the

spiral screen packing on various terpene mixtures.


-14-










CAHPTER II. PHYSICAL PROPERTIES
OF a- AND B-PINENE

Data in the literature show a wide variation in the
values for the physical constants for a-pineno(I) and

B-Pineno(II).

CH3 CH2



2 2 2


112 0 HC H C CH0
2^ /2 \l /^2
CH CH
a-pinene B-pinene
(I) (II)

With the fractionation columns previously discussed it
is possible to obtain a- and B-pinenes which should be of a

higher degree of purity than has been reported heretofore.

Preparation of a-pinne and B-pinene

a-Pinene was prepared by the careful fractionation of
four liters of commercial a-pinene2 from gum turpentine,

through a spiral screen column at 20 rm. pressure and a reflux
ratio of 40 to 1. This column oxorted 75 plates upon a mixture
of n-heptanc-ncthylcyclohezano at total reflux and atmospheric

pressure. Fractions wore collected at 75 cc. intervals. All

IThe vwork discussed in this chapter was done in collaboration
with V. David Stallcup.
Furnished through the courtesy of Southern Pine Chemical
Company, Jacksonville, Florida.
-15-










fractions with a refractive index in the range 1.4631-1.4633

at 25.00 were combined and refractionated through the same

column. Fractions were then collected at 50 cc. intervals

and their refractive indices and optical rotations were meas-

ured at 25.00. The fractions which had constant values of re-

fractive index and optical rotation were combined and were

considered to be pure a-pinene. In verification, a 100 cc.

portion of the latter was fractionated through a column which

had 60 plates determined as above. No change in those two

physical constants was noted at any point during collection

of the distillate.

a-pinene from wood turpentine was desired also. The prep-

aration of this pure component from wood turpentine involves

its separation front a small amount of camphene which boils

about 30 higher. The intermediate fractions having constant

refractive indices and optical rotations at 25.00 were then

combined and refractionated. The material thus obtained had

constant physical properties and was of the same purity as

the a-pinene from gum turpentine.

The B-pinene used was prepared in an analogous manner from

commercial B-pinene2 obtained from gum turpentine.


2Purchased from Hercules Powder Company.
Furnished through the courtesy of Southern Pine Chemical
Company, Jacksonville, Florida.


-16-











These purified pinenes had the following constants

B.p.,OC.
(20.0 mm.) n25-0D d25.04 (a)25.0D

a- (gum) 52.2 1.4631 0.8542 3.83
a- (wood) 52.2 1.4631 0.8542 +34.07
B- (gum) 59.7 1.4768 0.8666 -21.49


These constants are in close agreement with unpublished

data of Bain(13), with much of the data of Palkin and co-

workors(l,14), with data of Waterman, Van't Spijker and

Van Westen(15) and with some of the data of Dupont(16).

Experimental

Density Measurements. These were made with a 25 ml. den-

sity bottle. In all cases values were obtained at least in

duplicate which checked to the fourth decimal place. The

thermostat was controlled by means of an Aminco Metastatic

Thermoregulator connected to a vacuum tube relay circuit de-

veloped by Hershberg and Huntress(17). The thermoregulator

controlled the temperature within a limit of + 0.02.

Mixtures of a- and B-pinene were made up to known concen-

trations by weight. Measurements of the variation of density

with concentration were made using a-pinene from both gum and

wood turpentine. The densities of the mixtures were independent

of the source of the a-pinene used. The average deviation of

the density determinations was 0.00004. These data are given

in Table 2, page 18, and may be expressed at 25.00 by the


-17-















Table 2

Densities of Mixtures of a- and B-pinene


Mole
Fraction
B-pinene

0.000

0.162

0.292

0.402

0.497

0.623

0.703

0.846

1.000


5.0
observed

0.8542

0.8562

0.8579

0.8593

0.8605

0.8621

0,8630

0.8647

0.8666


25.0
d4
calculated

0.8542

0.8563

0.8579

0.8593

0.8605

0.8621

0.8630

0.8648

0.8666


-18-











equation


d25 o 0.8542 + 0.0129X 0.0005X2 (1)


in which X is the mole fraction of B-pinene.

Refractive Index Measurements. These were obtained with

the pure substances and their mixtures by means of an Abbe'

refractometer calibrated against a knovm glass. Constant

temperature was maintained by circulating water through the

refractometer from the thermostat described above. The average

deviation of the determinations was 0.00006.

Refractive index measurements of the two pure substances

for the temperature range 15-350 show that both a- and B-pinene

have a coefficient of 0.00045 unit per degree. The data is re-

corded in Table 3, page 20.

The variation of the refractive index with concentration

for mixtures of B-pincne and either gum or wood a-pinene at

25.00 may be expressed by the equation


n25OD = 1.4631 + 0.0144X 0.0007X2 (2)


where X is the mole fraction of B-pinene. The data is in

Table 4, page 21.

The molar refractions of the pure components were cal-

culated using the standard atomic refraction values of Auwers

and Eisenlohr and also a value of 0.48 for the cyclobutane

ring. In this manner the value of 43.99 was obtained for


-19-















Table 3

Variation of Refractive Index with Temperature


a-pinene
nD

1.4682

1.4663

1.4653

1.4636

1.4621

1.4607

1.4588

1.4631


B-pinene
nD

1.4818

1.4800

1.4789

1.4772

1.4758

1.4743

1.4725

1.4768


-20-


tC.


13.7

17.9

20.1

24.0

27.3

30.4

34.5

25.1




















Refractive Indices


Mole
Fraction
B-pinene


0.000

0.095

0.203

0.300

0.400

0.493

0.588

0.694

0.781

0.902

1.000


Table 4

of Mixtures of a- and B-pinene


n25.0
calculated


n25.0b
observed


1.4631

1.4645

1.4660

1.4673

1.4687

1.4700

1.4713

1.4727

1.4739

1.4755

1.4768


1.4631

1.4645

1.4660

1,4674

1.4687

1.4700

1.4713

1.4727

1.4739

1.4755

1.4768


-21-










both a- and B-pinene. From the observed data the values of

43.93 and 44.40 were calculated for a- and B-pinene, respec-

tively, by use of the Lorenz-Lorentz equation:

MrD M n2 1(
rD d n2 + 2 ()

where MrD is the molecular refraction

M is the molecular weight of the compound

d is the density of the compound

n is the refractive index of the compound

the NaD line.

The exaltation of 0.41 for B-pinene is probably due to the

presence of the exocyclic double bond. Auwers(18) has pro-

posed that values of from 0.32 to 0.52 be added to correct

for the exocyclic double bond.

Polarimetric Measurements. Since a-pinene has a rotation

that varies with its source, sample, and time of year collected

from the tree, the value of this constant has no diagnostic

significance(19). It has been pointed out by Darmois(20)

that B-pinene has a constant specific rotation regardless of

its source, and that this value is -22.440 for the j-line of

mercury. Dupont(16) reported a value of -22.480.

All rotations were observed at 25.00 in a jacketed two-

decimeter tube. A Duboscq polarimeter, reading by vernier to

0.010 of arc and equipped with suitable filters, depending on

the wave length of light, was used. Readings on the same tube


-22-











could be made with an average deviation of 0.020 using the

sodium light and 0.050 using a less intense mercury arc.

Listed in Table 5, page 24, are rotations of a- and

B-pinene and their mixtures for the NaD(589 mm.), Hgj (578 mm.)

and Hg (546 rm.) lines. Also given are the observed rotatory

dispersions. The rotatory dispersion of an optically active

compound is the ratio of its rotation for two different wave

lengths. This value of the dispersion varies with the w:ave

lengths used. Biot's law for the linearity of specific ro-

tations of mixtures does not hold exactly. The maximum de-

viation is about 0.30 at a mole fraction of 0.5. The data

could be expressed by a second degree equation. However,

this relation would change with the variation in the value of

the rotation of the pure a-pineno used.

Also, listed in column 3, Table 5A, are the mole fractions

of B-pincne calculated by Blot's law from the observed data

using the NaD line. The deviations for the Hgj and Hgv lines

are about the same.

Blot's law may be applied, to express rotatory dispersion

for a given mixture, in the form

(av nB-(aB-)v + (1 nB-) (a -)v (4)
alD nB-(B-)D + ( nB-) (-) (4)

in which nB_ is the mole fraction of B-pinene in the mixture,

(aB_)v and (aB_)D are the specific rotations of B-pinene with

the v-lino and D-line, respectively, and (a.a), and (aa-)D are


-23-










Table 5


A. Specific Rotations of Mixtures of a- and B-pinene


Mole
Fraction
B-pinene

0.000
0.110
0.205
0.290
0.394
0.495
0.581
0.680
0.806
0.887
1,000


(a)25.0D


- 3.83
- 5.69
- 7.32
- 8.71
-10.53
-12.26
-13.84
-15.67
-17.90
-19.44
-21.49


Mole Fraction
B-pinene
Biot


0.105
0.198
0.276
0.379
0.477
0.567
0.671
0.796
0.884


(a)25 j


- 4.03
- 5.96
- 7.61
- 9.02
-10.85
-12.61
-14.19
-16.05
-18.32
-19.86
-21.98


S25.0
(a) v


- 4.57
- 6.59
- 8.29
- 9.77
-11.67
-13.53
-15.17
-17.13
-19.50
-21.09
-23,28


B. Dispersions of Mixtures of a- and B-pinene


Mole
Fraction
B-pinene


0.000
0.110
0.205
0.290
0.394
0.495
0.581
0.680
0.806
0.887
1.000


(a)v/(a)D


1.193
1.158
1.132
1.121
1.107
1.103
1.097
1.093
1.089
1.085
1.083


Dev.xl03



-9
-4
-4
0
-2
-1
-1
-1
0


(a)v/(a)j


1.134
1.106
1.091
1.084
1.076
1.074
1.070
1.067
1.064
1.062
1.059


-24-










the specific rotations of a-pincne with the v-line and D-line,

respectively. When the values of dispersion are calculated

on this basis only slight variations from the observed dis-

persions are noted. This deviation is illustrated for the

(a) /(a)D dispersion by the data in column 3, Table 5B.

Dupont(20) observed that for high a-pinene content (ap-

proximately 70 mole per cent or greater) the dispersion is a

good indication of the a-pinene content. Ordinarily the

(a)v/(a)j ratio is used, probably because the two lines are

obtained from the same source. However, the data show that

(a) (a)D gives a wider dispersion range and therefore should
be a more satisfactory indication of the a-pinene content.

Vapor Pressure Measurements. These were determined in

the pressure range from 15 to 80 mm. by use of a distillation

column in which the vapors were allowed to come to equilibrium

with the liquid. The column temperature was adjusted to with-

in 1.50 of the temperature recorded by the condensing vapors

in the head. The temperatures of the vapors were measured by

the use of a calibrated mercury thermometer that could be

read to +0.050. The bulb of the thermometer was wrapped with

a single layer of cotton gauze.

The pressure was regulated by a manostat of the Hershberg-

Huntress type(17). The action of the vacuum pump on the mano-

stat was partially checked by placing a stopcock between the

pump and the manostat. The pressure fluctuations were mini-


-25-










mized by including a five gallon bottle in the system be-

twvocn the manostat and the column.

The manometer was connected to the head of the column

so that the pressure of the condensing vapors would be re-

corded. The vapor pressures were measured with a Germann

barometer, using a cathetometer which could be read to 0.01 mm.

The observed pressure readings were corrected to 00 for the

difference in the expansion of the mercury and the brass

scale at different temperatures(21) and were corrected to 450

latitude and sea level(22). At each recorded temperature

about 2 cc. of liquid was collected at a reflux ratio of 20

to 1.

Equations were obtained by applying the method of averages

to the corrected data. It was found that the equation

log p = 8.1020 2213/T (5)

represents the data for a-pinene for the stated pressure range.

The experimentally determined values agree with the values

calculated by the empirical equation with an average devia-

tion of 0.08 mm. and a maximum deviation of 0.2 mm. Similar-

ly, the equation

log p = 8.1504 2280/T (6)
represents the data of B-pinene for the same pressure range.

The experimentally determined values agree with the values

calculated by the empirical equation with an average deviation


IBuilt by G.T. Armstrong.


-26-










of 0.11 mm. and a maximum deviation of 0.4 mm. The observed

data and the calculations illustrating the application of

the method of averages are given in Table 6, page 28, and

Table 7, page 29, respectively.

The Clausius-Clapeyron equation may be written


d In p L (7)
dT
--dr y--r7
where L is the latent heat of vaporization

R is the molar gas constant (1.98 cals.)

T is Absolute temperature

p is pressure.

Assuming L and R to be constant, integration of equa-

tion (7) Gives

2.303(log p) = -L/RT + C

and log p = C' L/(2.303RT). (8)

The general form of this equation, corresponding to

equations (5) and (6) is

log p = A B(1/T)

where B = L/(2.303R)

and L = (2.303) (R) (B).

Thus from equations (5) and (6), the latent heat of

vaporization for the stated pressure range may be shown to

be 10,130 cal./mole or 74.35 cal./g for a-pinene and 10,430

cal./mole or 76.60 cal./g. for B-pinene.

-27-













Table 6


Vapor Pressures of a-Pinene


toC. TOA. p(mm.) 1/T log p p(mm.)
obs. calcd.


50.2 323.4
62.4 335.6
66.0 339.2
68.7 341.9
71.9 345.1
Summation

74.3 347.5
76.6 349.8
78.3 351.5
80.0 353.2
82.7 355.9
Summation'


18.1
32.1
37.9
42.7
49.0
(1/T)


54.0
59.7
64.0
68.6
76.7
(1/T)=


0.003092
0.002980
0.002948
0.002925
0.002898
= 0.014843;


0.002878
0.002859
0.002845
0.002831
0.002810
0.014223;


1.25768
1.50651
1.57864
1.63043
1.69020
7.66346 =

1.73239
1.77597
1.80618
1.83632
1.88480
9.03566 =


18.16
32.20
37.84
42.60
48.90
Summation


+0.06
+0.10
-0.06
-0.10
-0.10
(log p)


54.15 +0.15
59.65 -0.05
64.00 0.00
68.61 +0.01
76.56 -0.14
Summation'(log p)


Summation (log p)
Summation'(log p)

7.66346
(-) 9.03566
-1.37220


= Summation A BSummation (1/T)
= Summation'A B*Summation'(1/T

= 5A 0.014843B
= 5A 0.014223B
= -0.000620B


B = 1.37220/0.000620 = 2213.


Since 5A = 7.66346
5A = 7.66346


+ 0.014843B
+ 0.014843(2213)


A = 8.1020

Log P = 8.1020 2213/T


-28-


Dev.


(5)















Table 7


Vapor Pressures of B-Pinene


fA.


321.5
338.9
339.4
343.3
346.4
Summation

349.3
350.9
354.4
357.5
363.8
Summation'


p(mm.)
obs.


11.4
26.5
27.2
32.3
37.0
(1/T)

41.9
45.0
52.3
59.2
76.0
(1/T)


Summation (log p)
Summation'(log p)


1/T


0.003110
0.002951
0.002946
0.002913
0.002887
= 0.014807;

0.002863
0.002850
0.002822
0.002797
0.002749
= 0.014081;


Summation A -
Summation'A -


log p


1,05690
1.42325
1.43457
1.50920
1.56820
6.99212

1.62221
1.65321
1.71850
1.77232
1.88081
8.64705


p(mm.)
calcd.


Dev.


11.47 +0.07
26.44 -0.06
27.15 -0.05
32.27 -0.03
36.99 -0.01
a Summation(log p)

41.96 +0.06
44.93 -0.07
52.04 -0.26
59.35 +0.15
76.35 +0.35
= Summationt(log p)


B* Summation (1/T)
B Summation'(l/T)


5A -
5A -
-0.00072E


0.014807B
0.014081B


B 1.65493/0.000726 = 2280


Since 5A
5A


6.99212
6.99212


0.014807B
0.014807(2280)


A w 8.1504


a 8.1504


- 2280/T


-29-


tC.


48.3
65.7
66.2
70.1
73.2


76.1
77.7
81.2
84.3
90.6


6.99212
(-) 8.647055
-1.65493


log p


(6)










The isobaric vapor-liQuid compositions at 20.0 mm.

These were determined using a modified Sameshima appara-

tus(23). This is designed so that if a liquid mixture is

boiled in the flask, the vapor in equilibrium with the

liquid mixture is condensed in a small bulb. The overflow

from the bulb, as the vaporization continues, is returned

to the flask. Since the bulb has a volume of 5-6 ml.,

time must be allowed for complete equilibrium to be attain-

ed.

About 100 cc. of mixture was placed in the flask and

then brought to equilibrium, which was generally reached

within two hours but four hours were allowed before a final

measurement was made. Samples were then withdrawn from the

flask and from the vapor receiver. The rate of flow, which

averaged 1.5 cc./min., was regulated by the voltage applied

to the internal heater. The thermostat temperature was kept

about 2-40 above the estimated boiling temperature of the

liquid. Cold brine solution was circulated through the two

condensers, each of which contained a condensing coil made

from a four foot length of glass tubing. Experiments showed

that there was no detectable vapor loss four hours after

reaching equilibrium between liquid and vapor. The pressure

control system was the same one described for the measure-

ments of vapor pressures of the pure compounds. Samples were

withdrawn by means of capillary pipets. Data were observed

-30-











by starting with mixtures rich in a-pincne and going to mix-

tures rich in B-pincno and also by starting with mixtures

rich in B-pincno and going to mixtures rich in a-pinenc. The

compositions were determined by means of refractive index

measurements and application of equation (2). The data ob-

tained by this method are recorded in Table 8, page 32.

In order to compare the observed values with those of

an ideal sycten, pressures, pa- and PB of the pure com-

ponents were calculated by equations (5) and (6) for the tem-

peratures listed in Table 9, page 33. Then for each tempera-

ture was calculated a liquid mixture composition at 20.0 mm.

by applying Raoult's law in the form

20.0 = xa.pa- + (1 x-)pB- (9)

where xa- is the mole fraction of a-pinene in the liquid

phase. The corresponding vapor composition was calculated

from the relation

y Xa-Pa- (10)

where ya- is the mole fraction of a-pinene in the vapor phase.

The observed mole fraction of a-pinene in the vapor, correspond-

ing to liquid composition x in column 4, Table 9, was ob-

tained from a plot of the vapor-liquid relations at 20.0 m.,,

using the data in Table 8. The difference between the observed

and calculated vapor composition is a measure of the devia-

tion from ideality of the mixtures. These deviations are

listed in the last column of Table 9.


-31-














Table 8


Liquid-Vapor Composition at 20 m.,


n25.0D
liquid


1.4759
1.4758
1.4754
1.4751
1.4747

1.4745
1.4731
1.4727
1.4722
1.4718

1.4713
1.4710
1.4706
1.4698
1.4691

1.4689
1.4680
1.4676
1.4668
1.4662

1.4653
1.4650
1.4648
1.4647
1.4641
1.4637


Mole Fraction
a-Pinene in
Liquid

0.070
0.075
0.105
0.130
0.160

0.175
0.280
0.310
0.345
0.375

0.415
0.435
0.465
0.525
0.575

0.590
0.655
0.680
0.740
0.780

0.845
0.865
0.880
0.890
0.930
0.955


n25.0D
vapor


1.4757
1.4756
1.4751
1.4747
1.4742

1.4740
1.4722
1.4718
1.4712
1.4708

1.4702
1.4699
1.4694
1.4686
1.4680

1.4678
1.4671
1.4667
1.4661
1.4656

1.4649
1.4647
1.4645
1.4644
1.4639
1.4636


-32-


Mole Fraction
a-Pinene in
Vapor

0.085
0.090
0.130
0.160
0.195

0.215
0.345
0.375
0.420
0.450

0.495
0.515
0.555
0.610
0.655

0.670
0.720
0.745
0.790
0.825

0.875
0.890
0.905
0.910
0.945
0.965











Table 9


Deviation of Vapor Concentration as Calculated by Raoult's Law


S Pa_-
t, C. calcd.


52.6
53.0
54.0
55.0
55.5
56.0
57.0
58.0
59.0
59.4


20.39
20.79
21.80
22.87
23.41
23.97
25.12
26.32
27.56
28.14


PB-'
calcd.



14.20
14.48
15.21
15.98
16.37
16.77
17.60
18.47
19.37
19.74


Xa-'
Mole Fract.
a-pinene
in liquid
calcd.

0.937
0.875
0.727
0.583
0.516
0.449
0,319
0.195
0.077
0.031


Ya-
Mole Fract.
a-pinene
in vapor
calcd.

0.955
0.909
0.792
0.667
0.603
0. 5,8
0.401
0.256
0.106
0.044


a-#
Mole Fract.
a-pinene
in vapor
obs.

0.950
0.900
0.780
0.662
0.601
0.533
0.388
0.238
0.095
0.039


Summary


The densities, refractive indices and optical rotations

for a- and B-pinene and their mixtures have been determined.

The vapor pressure-temperature relations of a- and

B-pincne were measured in the range of 15 to 80 mm.

The vapor-liquid equilibrium composition data for mix-

tures of a- and B-pinene at 20 mm. pressure have been de-

termined.


-33-


Valior
Dev.



0.005
0.009
0.012
0.005
0.002
0.005
0.013
0.018
0.011
0.005










CHAPTER III. THE THERMAL ISOMERIZATION

OF a-lPINENE

In 1853 Berthelot(24) heated French turpentine in seal-

ed tubes at 2500 for 10 hours. Polymerization occurred, ac-

companied by a change in rotation, and he noted that there

was no gas formation. Wallach(25) found that a-pinene form-

ed dipentene(III) and some

polymerized material when 3

heated at 250-2700. 21 CH

The first rate determi-

nations of this reaction were HC CH

made by D. F. Smith(26). He

determined the rate by heating 530 C2

sealed tubes of a-pinene in a D
Dipentene
temperature controlled oil (III)

bath and measuring the rate of

decrease of the optical rotation of the reacting mixture.

The temperature range vwas 184-2370. Smith made most of his

determinations by putting just enough a-pinene in the tubes

so thzt it '.as present in the gas phase only, at the tempera-

tures of the experiment. Some determinations were made with

a-pinene in various solvents. In only one tube did a-pinene

remain in the liquid phase. This rate was determined at


-34-











184.60 and was found to be of the same order of magnitude

as the rate in the gas phase. He found the reaction to be

of first order and assumed it to be a racemization of the

a-pinnee. Smith distilled the partially reacted mixture

from the tube in which the a-pinene remained in the liquid

phnse and found its boiling point to be about 4 hlGher

then that of the original mixture. The first part of the

distillate had an optical activity 20% higher than that of

the mixture but lower than that of the original a-pinene.

To account for this he explained that in all probability

"a small fraction of the changes of one active variety of

pinene to the opposite variety is accompanied by rearrange-

ment of the molecule to form a high-boiling substance, which

judging from the literature, should be limonene."

Conant and Carlson(27) proved that dipentene was form-

ed in this reaction both in the liquid and the vapor phase

at about 2000. They were unable to fractionate known mix-

tures of a-pinene and dipentene with any efficiency through

the columns at their disposal and resorted to measuring the

amount of hydrogen absorbed by the reaction mixtures in

order to determine the amount of dipentene formed. The in-

crease in the amount of hydrogen absorbed was found to vary

linearly with the decrease in optical rotation of the reac-

tion mixture although the percentage error of a single de-

termination was rather high. The lighter boiling fractions


-35-










of the pyrolysate yielded a crystalline tetrabromide cor-

responding to that of dipontene. In addition they noted

that an appreciable amount of polymerized material was ob-

tained in the tubes in which the reaction went nearly to

completion. Kassel(28) pointed out that on the basis of

the results of Conant and Carlson the rate constants for

the isomerization of a-pinene to dipentene would be twice

those calculated by Smith for the racemization of a-pinene.

Thurber and Johnson(29), in an attempt to show that

different isomers of a-pinene exist, determined the ener-

gies of a-pinene from two different sources. They followed

the procedure of Smith. An appreciable difference in the

energies of activation was found. However, this could

have been due to impurities present in the samples of a-pin-

ene used. Upon fractionating approximately 20 cc. samples

of reaction mixture they found that most of each sample dis-

tilled above 1590 at atmospheric pressure, which was higher

than the boiling point of the substrate, and hence concluded

that the reaction was not a simple racemization.

In reviewing the results of the studies of this reac-

tion prior to 1931 it should be noted that efficient frac-

tionating columns were unavailable both for the purification

of the substrate, a-pinene, and for the analysis of the

products.


-36-










Since that time some interesting results have been ob-

tained on passing a-pinene vapors through hot tubes at

various temperatures. At 240-2500 Arbuzov(30) found that

as much as 26% of allo-ocinmone(IV) was formed. Dupont and

Dulou(31) using a copper tube

packed with copper gauze ob- CH3

trained at these temperatures C=CH-CH=CH-C=CH-CH3
CH
not only allo-ocimene and di- 3
Allo-ocimene
pentene but also a-pyronene(V) (IV)

and B-pyronenc(VI), which they

characterized. Goldblatt and Falkin(32) isomerized

d-a-pincne in an all glass apparatus and at 3750 obtained

about 12, a- and B-pyronene, 42% dipentene and 40% allo-

ocimene.


CH3 CH3

E1C-CH -1H C-113

HC C H HC CI3
H H2

a-pyronene B-pyronene
(V) (VI)

In view of these facts and with the previously de-

scribed spiral screen fractionating columns available it

seemed advisable to re-investigate the kinetics of the


-37-










liquid phase thermal isorerization of a-pinene within the

temperature range used by Smith(26). As this investiga-

tion proceeded it became evident that a more complete

study of the over-all reaction should include a study of

the polymerization of allo-ocimene.

Experimental

Purification of reactants. A commercial grade of d-a-

pinene from wood turpentine was carefully fractionated

through a five foot length of spiral screen column of

37 mm. (1.45 inch) inside diameter. This necessitated the

separation of a-pinene from a slightly lower boiling frac-

tion and from camphene which boils about 30 higher than a-

pinene. The fact that the rotation and the refractive in-

dex of the a-pinene obtained varied slightly indicates

that traces of impurities were not removed. However, the

amounts of these impurities was insufficient to appreciably

affect the results.

The allo-ocimenel was fractionated in 200 cc. batches

through a four foot spiral screen column (inside diameter 10

mm. (0.40 inch). The small amount of dipentene initially

present in the samples and an intermediate fraction boil-

ing at 75-770 at 10 rmn., were discarded.

These compounds had the following range of physical


1Samples furnished through the courtesy of Naval Stores
Research Laboratory, U.S.D.A. and of Southern Pine and
Chemical Company.
-38-










constants:

a-pincne: b.p.20.0 mm52.30; a25D(2 dmi.) +57.520- +58.260;

n25.0D 1.4631-1.4632.

10 m-i. o "25.0
allo-ocimenet b.p.10 mn977-780; d25 0.8050-0.8056;

n25.0D 1.5418-1.5424.


Apparatus. The sealed tubes of liquid were heated in

a well insulated bath containing 5 gallons of oil agitated

by two motor stirrers. Hydrogenated cottonseed oil, which

was used at first, gradually polymerized and was replaced

by white paraffin oil. The temperature of the bath was

maintained constant by means of an Aminco Metastatic Ther-

morcgulator connected to a vacuum tube-relay circuit de-

veloped by Huntress and Hershberg(33). Heat was supplied

by two 250 watt blade heaters, one connected to the tem-

perature control circuit and the other directly to the

current source. A Beckmann thermometer placed in the bath

showed an average variation of +0.030 and a mAximum varia-

tion of +0.040. The Beclknann thermometer showed that the

average temperature of the bath did not change during the

course of the heating. The bath temperature measurements

were based on a thermometer calibrated by the U.S. Bureau

of Standards (reading directly to 0.10). The temperatures

used in the experiments wero 189.50 and 204.50.


-39-










Two spiral screen columns of 10 mm. (0.40 inch) inside

diameter, four feet in length, were used to analyze the re-

action mixtures. Ice water at 4-120C. was circulated

through the column head condensers. In addition, ice-HC1

traps were placed in the system between each column and

the manostat. Very little condensate was collected in the

traps (usually less than 0.1 mn.). All fractionations were

made at pressures between 10 and 20 mm.

Preliminary Procedure. In determining the amount of

a-pinene to be used for each reaction two factors were con-

sidered. The volume should be small enough that the liquid

could be contained in a sealed glass tube capable of with-

standing the pressures developed at the temperatures used

but large enough that the amounts of material obtained be-

tween the pure fractions during the fractional distilla-

tions would have a small effect on the quantitative estima-

tion of the components. It was found that lengths of

heavy-walled Corning G-1 glass tubing of 27 mm. (1.08 inches)

inside diameter could be purchased for constructing the

tubes. To attain complete immersion in the oil bath these

tubes could be only 10-11 inches long. Since 2-3 inches of

free space should be left above the liquid in the tube, the

volume to be filled with liquid would be 90-100 cc. In

every caso 94 cc.(80 gm.) of a-pinene was placed in a tube.











The amount of allo-ocimene in each sealed tube for

the separate polymerization study was limited by the small

amount of allo-ocimene available. Samples of 17.5-20 cc.

(14-16 gm.) of allo-ocimene were placed in 35 cc. tubes

made from 20 mm. (0.8 inch) inside diameter glass tubing.

A sealed tube containing 94 cc. (80 gm.) of a-pinene

and an enclosed thermometer (which read about 0.60 low)

was used to measure the rate of heating and of cooling of

the a-pinene under the conditions used. The data are

given in Table 10, page 42. To measure the rate of heat-

ing the tube was placed in the oil bath for varying lengths

of time and then withdrawn and the temperature of the liquid

observed. The tube was allowed to cool to room temperature

between each determination and the time recorded is the

total time taken for the tube to attain the temperature in-

dicated in the table. An additional 250 watt heater was

turned on during the interval that the tube was being heat-

ed to temperature in order to counteract the cooling of the

oil by the tube.

The rate of cooling was determined by removing the

tube from the bath after it had reached constant temperature

and observing the temperature of the liquid in the tube at

various time intervals. The times recorded are the total

time taken for the tube to cool from the bath temperature

to the observed temperature.


-41-













Table 10

Rates of Heating and cooling of a-Finene


A. Temperature 189.50C.


Heating


Cooling


Temperature
oC.


26
169
180
186.5
188.8


Time
min.


0
1
2
3.5
4.5


Temperature
0C.

188.8
178
168
151
142


B. Temperature = 204.50C.


Cooling


Temperature
OC.


Time
min.


25
186
196
202
204


Temperature
C.

204
195
183
175
165
156
147


-42-


Time
min.


Heantin


Time
min.














Table 11


Rntes of Heating and Cooling of Allo-ocimene

A. Temperature = 1890.50C.


Heating


Cooling


Temperature
OC.


Time
min.


25
170
18G
180
188.8


Temperature
Oc.

188.8
175
160
146


B. Temperature = 204.50C.


Cooling


Temperature
oC.

25
195
201
203
204
204


Time
min.

0
1
2
3
4


Temperature
OC.

204
187
171
155
141


-43-


Time
min.


Heating


Time
min.










The rate of cooling is so rapid that no appreciable

reaction will occur after the tube is removed from the

bath. At each temperature, an appreciable amount of re-

action should occur about five minutes after the tube' is

immersed in the bath. However the final temperature is

not reached for another six or seven minutes. In each

case a correction of about eight minutes should be al-

lowed and so the time of heating of the a-pinene tubes

was recorded as starting eight minutes after the tubes

were immersed in the oil bath. This correction is of no

significance for tubes heated more than 25 hours.

Similar experiments with 20 cc. (16 gm.) of allo-

ocimene in a sealed tube with an enclosed thermometer showed

that at each temperature six minutes were required to raise

the temperature of the liquid to that of the bath. Based

on the heating data in Table 11, page 43, the time of heat-

ing of the tubes of allo-ocimene was recorded as starting

4 minutes after the tubes were inserted in the bath.

Procedure. The 94 cc. portions of freshly distilled

a-pineno were placed in 130 cc. tubes made from the Corn-

ing G-1 glass tubing. These tubes had been sealed at one

end and had a tubular opening of 5 mm. (0.2 inch) inside

diameter at the other. Each filled tube was connected to

a vacuum line at 3-4 mm. and evacuated for five minutes.


-44-











The tubes were then sealed under vacuum.

The 17.5-20 cc. portions of freshly distilled allo-

ocimeno vere placed in the 35 cc. tubes which were evac-

uated and sealed in the same manner as described for the

tubes of a-pinene.

After these sealed tubes had been placed in the oil

bath and heated for the desired length of time, they were

opened and analyzed. The amount to be fractionated was

weighted. During the distillation all fractions were col-

lected in 15-20 cc. receivers which had been weighed

previously. When a fraction was cut by removing the re-

ceiver from the head it was weighed and the weight of the

fraction determined by difference.

Identification of Froducts. Four major components

were found in the mixtures: unreacted a-pinene, dipentene,

allo-ocirene, and a polymer. Upon the fractionation of the

mixture the polymer was left in the kettle and was weighed.

a-Pinene Fraction: The recovered a-pinene had virtually

the same physical properties as the original with the ex-

ception of optical rotation. In the tubes which had little

a-pinene left it was sometimes difficult to recover pure

fractions of a-pinene but in most cases this was done.

There can be little doubt that the recovered material was

mainly a-pinene. For example, the first fraction of Tube

No. 14, in which at least 95% isomerization had occurred,


-45-








was a 2 cc. portion, b.p. (21 mm.) 52.8-53.2, n25D 1.4630,

d254 0.8525, a25D (2 dm.) +20.460. A nitrosyl chloride was

made by the method of Thurber and Thielke(33) by adding 3 cc.

of 90% methyl alcohol and 2.5 cc. of isoamyl nitrite to it.

This mixture was placed in a flask equipped with a mechanical

stirrer and maintained at -100 to -200 while 5 cc. of 4.7 N

HC1 in 90% methyl alcohol were slowly added over a period

of 40 minutes. The solution had a blue-green color and a

small amount of the derivative was suspended in it. This

was filtered in a funnel which had been cooled in the ice-

box, and dried between clay plates. It melted 101-103.

Crystallization from benzene yielded a small amount melting

with decomposition at 104-1050 C. The nitrosochloride of

a-pinene was reported originally by Tilden and Shenstone(34)

as melting at 1030. However it was noted by Tilden(35) at

a later date that recrystallization of this compound raises

the melting point from 20 to 120 depending on the solvent.

Simonsen(36) states that since the melting is accompanied

by decomposition, the melting point varies with the rate of

heating and is usually found to be about 105-1080.

Dirpntcne FrAction: All of the dipentene from the tubes

heated at 189.50 was combined and fractionated. It con-

tained little impurity. The main portions had the physical

properties:

b.p.(10 mm.) 590; d254 0.8387; n25D 1.4702; a25D(2 dm.) -4.600.


-46-








The dipentone was identified by its tetrabromido. 7.5 gm.

were dissolved in 60 cc. glacial acetic acid and 6 cc. (17.6

gm.) of bromine were added slowly with constant shaking.

When all but 0.3 cc. had been added the color of the solution

began to redden but the remainder of the bromine was added.

The solution was allowed to stand for two days during which

the precipitate formed. It -ras filtered from the solution,

washed with acetic acid and dried. After recrystallization

from methyl alcohol the crystals were dried between clay

plates. They melted 124-1250. Wallach(37) first prepared

thick compound and reported a melting point of 1250. Gold-

blatt and Polkin(32) reported a melting point of 124.5-

125.50.

Fraction Intermediate between a-Pinene and Dipentene. 2-7%

(1.5-5 gn.) of each reaction mixture boiled between a-pinene

and dipentene. This portion no doubt contained mainly a-

pinene and dipentene. There was some evidence of the presence

of other compounds, particularly in those tubes which had

reacted for the longer times. In these tubes an appreciable

fraction of b.p. 53-600 (20 mm.) was sometimes obtained.

This fraction could contain a small amount of c.:mphene which

might have been present in the original a-pinene and also a

small amount of a-pyronenc. Dupont and Dulou(38) give for

a-pyronene a boiling point of 430(11 mm.) and a refractive

index (250) of 1.4665. However, three attempts to make the

maleic anhydride addition product of a-pyronene from some

of these fractions were unsuccessful.


-47-






For the fraction of b.p. 60-720 (20 mm.) the refractive

index was sometimes too high for that of dipentene; in the

case of Tube No. 14, 1.0 gm. was obtained with an index of

1.4727. Dupont and Dulou(38) list the refractive index of

B-pyronene whici boils in this range as 1.4747. However an

attempt to obtain a maleic anhydride addition product from

this fraction was unsuccessful. The second fractions of

Tubes No. 29 and 30 were combined (3 gm.; n25D 1.4710; b.p.

(20 mm.) 57-720). From this a meleic anhydride addition

product was made by adding 2 gm. of maleic anhydride and

heating the mixture on the water bath for one hour. Upon

cooling a gum separated from the liquid phase. The gum was

washed with water and crystallized from methanol. It melted

at 157-158. Dupont and Dulou(38) found for the maleic an-

hydride addition product of B-pyronene a melting point of

154. Goldblatt and Palkin(32) list it as 163-164.

Allo-ocimene Fraction: The allo-ocimene was seldom obtained

pure in these fractionations. The refractive indices (250)

were in the range 1.5330-1.5410. Only 1-3% of each mixture

was found to boil between pure dipentene and the allo-ocimene

obtained. This intermediate portion was combined with the

allo-ocimene portion for all the tubes heated at 189.50 and

the mixture fractionated. There were obtained 15 gm. of di-

pentene, 3.2 gm. of intermediate fraction and 29 gm. of allo-

ocimene, b.p. (11 mm.) 76-790; n25D 1.5408-1.5424; d254 0.8068-

0.8083. From this distillation it is obvious that no appre-


-48-









cable amount of compound is formed boiling between dipentene

and the allo-ocimene. The allo-ocimone portion had a boil-

ing range which could not be attributed to the presence of

dipentene as may be seen from the refractive index and den-

sity rinces. Similar behavior was noticed during the frac-

tionation of the commercial samples of allo-ocimene. However

in these latter cases a much higher percentage of high boil-

component was obtained.

Tlhe allo-ocimene was identified by its maleic anhydride

addition product which was prepared by the method of Gold-

blatt and Palkin(32). 7.3 gm. of allo-ocimene (n25D 1.5415)

was added to 5.5 gm. of maleic anhydride in a test tube

which was then suspended in a beaker of boiling water for

1.5 hours. The product was distilled at 190-192o at 9 mm.

The yield (10 in.) was unshed with heptane and recrystallized

from hexane. Large white crystals, m.p. 81.0-81.50, were

obtained. Arbuzov(30) reported a melting point of 81-820,

and Goldblatt and Palkin, after two recrystallizations from

hexane, obtained crystals melting 83-84o.

Polymor: The polymer obtained had refractive indices (250)

varying from 1.5130 to 1.5230. In the tubes heated for the

longer times this value was always close to 1.5190. A por-

tion of the polymer (n25D 1.5180, d254 0.8857) was distilled

with the results given in Table 12, page 50.

Molecular weight determinations by the freezing point


-49-






depression method were made of fractions 2 and 3, using

cyclohexane (n25D 1.4233; f.p. 5.900C.; molal f.p. depression

20.00) as the solvent. If the polymer were a dimer (C20H32)

the molecular weight would be 272. Four determinations on

fraction 2 gave an average molecular weight of 262 with an

average deviation of 0.75% and a maximum deviation of 1.90%.

Two determinations on fraction 3 gave values of 284 and 285,

respectively. From those results the polymer appears to be

a dimer.



Table 12

Fractionation of the Polymer

Fraction Weight
Ho. gms. B.p. 8.*) n'2D

1 2.4 120-165 1.5194
2 30.0 165-175 1.5177
3 2.5 224-226 1.5189
(3-4 mm.)
4 0.4 Residue



Quantitative estimation of comroncnts.- The use of

refractive index data to analyze the composition of each

fraction collected seemed practicable. By careful frac-

tionation not rore than two of the major components should

be present in each fraction. Refractive index-composition

data for Iknon mixtures of a-pinene and dipontene were

measured. The data ure recorded in Table 13. Column 3

gives the correction to be added to the weight % in column

1 to obtain a straight line relation between n25D and the

weight %. In view of the fact that a variation of 1.3% in


-50-







the concentration of dipcntene is represented by a change

of one part in the fourth decimal place of the refractive

index and since the maximum deviation from a straight line

in tho observed data is 1.1% all analyses were based on a

straight line relation.

Since a small percentage of other components (probably

comphene, a- and B-pyronene) is present in the range boiling

between a-pinene and dipenteno an error exists in calcu-

lating the percentage of these latter components on the

basis of refractive index. The refractive indices of cam-

phone, a- and B-pyronene are higher than that of a-pinene

and would tend to increase the calculated percentage of

dipenteno.

This is illustrated in the case of Tubes No. 29 and

50. These were heated at 204.50 for a length of tnie such

that less than 0.5% a-pinene should have remained. About

4% of each reaction mixture distilled at 20 mm. between

530 and the boiling point of dipentene (720 at 20 mm.)

and the refractive indices (250) of these fractions were

in the rrnge 1.4680-1.4720. This should represent the max-

inum n mount of impurity which has been calculated as dipen-

tcne. These lower boiling fractions no doubt contained

cone dipentene. Thus it is probably that the error in

the determination of the dipentene for these tubes does not

exceed 3%.

A small amount of camphcne (about 0.5%) mny be initially









present in the substrate. The pyronenes increase in amount

with the time of heating until, at the virtual completion of

the isomerization of a-pinene, the pyronenes plus the camphene

constitute about 3% of the reaction mixture. The total cor-

rection for the percentage of camphene and the pyronenes was

obtained by assuming 0.5% of camphene and a linear increase

in the pyronenes with respect to the amount of a-pinene reacted,

until at complletion of the reaction 2.5% of the pyronenes are

present. By subtracting this correction from the percentage

of dipentono determined on the basis of refractive index a

more accurate value of the dipentene concentration is obtained.

The percentage of a-pinene should be little affected.

It is believed that the a-pinene can be estimated to +1% from

refractive index measurements.

Similar data were obtained for mixtures of dipentene

and allo-ocimeno and are recorded in Table 14, page 53. The

maximum deviation from a linear relation is about 1.3% di-

penteno at 40% dipentene. Such a small deviation when applied

to mixtures of not over 10 grams rould have no significant

effect in the determination of the quantity of dipentene.

Actually the weight of any fraction containing this mixture

never exceeded 6 grams. Therefore oil calculations of com-

position for mixtures of allo-ocimene and dipentene were made

assuming a linear relation between refractive index and com-

position.


-52-















Table 13


Refractivc Indices of Mixtures of
a-Pinene and Dipentene


Weight %
Dipentene

00.0
19.4
29.2
53.6
81.8
100.0


n25D


Correction


1.4631
1.4644
1.4651
1.4669
1.4689
1.4702


-1.1
-1,0
0.0
-0.1


Table 14
Refractive Indices of Mixtures of
Allo-ocinene and Dipentene


Weight %
Allo-ocimene
(n25D 1.5415)

00.0
14.3
24.9
40.7
56.7
71.1
83,2


n25D

1.4702
1,4808
1,4885
1.4999
1.5112
1.5212
1.5299


Correction


+0,6
+0.8
+1.3
+0.5
+0.5
+0.6


-53-









In the fractionatlons of the reaction mixtures one

to one and a half grams of material usually were unaccounted

for. When the column and head were not immediately rinsed

out following a distillation a white gummy solid formed in

small amounts in the column head and sidearm. Allo-ocimene

forms such a compound when exposed to the air and it is

believed that most of the material unrecovered was allo-

ocimene. To trace this loss of material and to check the

applicability of the refractive index data to the analysis

of the components, test mixtures of known comrlosition were

fractionated in the analytical columns. The analyses were

made on the basis of refractive index as discussed above.



Table 15

Fractionation of Test Mixtures

Wt. a-pinene Ft. dipentene Wt. allo-ocimene Wt. polymer
act. obs. lev. act. obs. dev. act. obs. dev. act. obs. dev.
1. 42.3 42.1 -0.2 14.5 14.6 +0.1 4.3 3.7 -0.6 4.4 4.2 -0.2
2. 9.8 9.6 -0.2 49.8 49.7 -0.1 3.5 3.2 -0.4 12.6 12.5 -0.1
. --- --- 6.6 6.3 -0.3 3.1 2.2 -0.9 4.7 4.9 +0.2
4. --- --- 5.3 4.8 -095 2.1 1.4 -0.7 10.2 10.1 -0.1
av. loss = 0.2 av. loss = 0.2 av. loss = 0.65 av. loss = 0.05



The average losses are 0.05 gra. of polymer, 0.2 gm. of

a-pineno, 0.2 gin. of dipentene and 0.65 gm. of allo-ocimene.

To reduce the effect of the appreciable loss of allo-ocimene

on the calculations a correction of 0.5 gm. was added to the

observed weight of allo-ocimene in each analysis.


-54-










Isomerization of a-Pincnc. Duplicate tubes of a-pinene

were heated at 109.50 for periods of from 20.5 to 607 hours

and at 204.50 for periods of front 7.33 to 267 hours. Tables

16 and 17, page 56 and 57, give the physical properties of

the reaction mixtures immediately after the tubes were open-

ed.

The refractive indices and boiling points of the frac-

tions obtained by distillation of these reaction mixtures

are given in Tables 35-65 (appendix).

Effect of 1lent on Allo-ocimene and Dipentene. IIarries(39)

reported that dipentene is unreactive when heated in sealed

tubes at temperatures up to 3000. To verify this, two seal-

ed tubes, each containing 14 gm. of the purified dipentene,

were heated for four hours in an oil bath at 245-2550. Frac-

tionation of the combined product yielded 26.6 gm. of unchanged

dipentene and 0.3 gin. of a high-boiling residue (n25D 1.5007).

A sealed tube containing 17 Ln. of a mixture of 46%

allo-ocimcne and 54, dipentene was heated for four hours

under the same condition. By fractionation of the products

the dipentene was recovered unchanged. In addition, the

products contained about 2, of a lower boiling fraction,

310 of polymer and 13% of unreacted allo-ocimen. From this

it is apparent that the dipentene yields no products, that

it is not appreciably involved in the formation of the poly-

mer and that the allo-ocimene alone forms the polymer.

-55-













Table 16


Physical Properties of Reaction Mixtures

Temperature = 189.50


Tube Time
No. Heated
Hours


1
2

3
4

5
6

*40
*41

7
8

9
10

11
12

13
14


20.5
20.5

51.0
51.0

82.0
82.0

130.0
130.0

178.0
178.0

250.5
250.5

377.0
377.0

607.0
607.0


% a-pinene
unreacted


88.3
88.3

76.5
76.3

65.7
64.2

50.5
50.2

37.7
37.2

25.9
25.8

13.9
14.0

3.9
5.0


n25D


1.4658
1.4656

1.4692
1.4692

1.4722
1.4721

1.4754
1.4754

1.4780
1.4780

1.4805
1.4804

1.4828
1.4828

1.4852
1.4849


25
a 25D(2 dn.)


+50.66
+50.80

+41.60
+41.50

+33.80
+33.80

(-2.80)
(-2.82)

+18.85
+18.90

+ 9.70
+10.00

+ 3.10
+ 3.05

1.43
1.52


*These tubes contained g-pinene from gum turpentie,
b.p. g2.2 (20 mm.), n2 D 1.4631, d254 0.8542, a'D (2 dm.)
-6.49.


-56-


25
d 25


0.8506
0.8506

0.8488
0.8491

0.8481
0.8483

0.8476
0.8477

0.8476
0.8477

0.8479
0.8481

0.8490
0.8494

0.8510
0.8508
















Physical



Time
Heated
Hours

7.33
7.33

13.75
13.75

20.0
20.0

25.0
25.0

34.0
34.0

51.0
51.0

101.0
101.0

267.0
267.0


Table 17

Properties of Reaction Mixtu

Temperature = 204.50

% a-pinene 25
unreacted n D


85.5
86.2

74.1
74.1

64.8
65.3

58.7
58.4

48.1
48.1

32.1
32.1

11.1
11.2


1.4678
1.4677

1.4708
1.4708

1.4734
1.4732

1.4745
1.4746

1.4772
1.4771

1.4806
1.4806

1.4852
1.4853

1.4869
1.4867


ires




a25D (2 dn.)


+47.28
+47.46

+39.62
+39.74

+32.50
+32.64

+28.45
+28.29

+22.40
+22.43

+13.48
+13.61

+ 1.33
+ 1.38

2.18
2.15


-57-


Tube
No.


15
16

17
18

19
20

21
22

23
24

25
26

27
28

29
30










Arbuzov(30) heated allo-ocimene in a sealed tube for

one hour at 250-3000 and one-half hour at 3200. Upon frac-

tionation he obtained 7 gn. of material boiling from 550(14 mm)

to 135 (4 mm) and 8 gm. of a polymer. Arbuzov reported that

refractionation of the lower boiling portion yielded 5 gn.

of a terpene, b.p. 57-58.50 (14 mm.), n25D 1.4785,d20 0.8422.

This terpene gave no crystalline tetrabromide nor nitrosite.

He did not attempt to prepare the maleic anhydride addition

product. From the similarity of the physical properties of

this terpene to those reported by Dupont and Dulou(38) for

B-pyronene it was suspected that this might be B-pyronene

formed by the cyclization of allo-ocimene. To check this

point, 60 gm. of allo-ocimene were heated at 300-3100 for

two and a half hours in a sealed tube. The products obtain-

ed were divided into four main fractions:

Fraction 1. 9% b.p. (20 mm.)43-570 n25D 1.4663

Fraction 2. 15% b.p. (20 mm.)57-690 n25D 1.4791

Fraction 3. 12% b.p. (20 mm.)69-90 n25D 1.4848

Fraction 4. 64% Polymer n25D 1.5166

Before the analyses of these fractions were started Gold-

blatt(40) stated that he had already completed experiments

proving that a- and B-pyronene are formed by the cyclization

of allo-ocimene. Since Fractions 1 and 2 have physical

properties which correspond to those of a- and B-pyronene,


-58-











respectively, maleic anhydrido addition products were made

of these two fractions.

4.5 gnu. of Fraction 1 were added to 4 ~,i. of maleic

anhydride and heated on a water bath for three hours. The

product wns distilled yielding 0.8 g. of oil, b.p. (12 mm.)

48-54, n25D 1.4668 and 3 Gm. of a viscous material, b.p.

(12 mm.) 202-204. This latter fraction was probably the

addition product of maleic anhydride with a-pyronene. How-

ever, repented attempts to recrystallize it from methanol

were unsuccessful.

7.5 g. of Fraction 2 were added to 6 Uc. of maleic

anhydride and heated for one hour. Distillation of the mix-

ture gave 6 gm. of an addition product, b.p. (12 mm.) 195-

198. This was crystallized from aqueous methanol. The

crystals melted at 161-1620. Goldblatt and Palkin(32) re-

ported a melting point of 163-164o for this derivative of

B-pyronene.

These findings confirm the report of Goldblatt that

allo-ocimene cyclizes to form the pyronenes.

Kinetics of the Isomerization. The quantitative analyses

of the isomerization products of a-pinene indicated that the

amount of dipentene increased continuously. The monomeric

allo-ocimone reached a maximum value when the a-pinene was

40-75, isomerized and then slowly decreased, while the poly-

mer continuously increased.
-59-










From these data it is probable that the dipentene and

allo-ocimene are produced by simultaneous side reactions,

and the polymer by a consecutive reaction from the allo-

ocimene.

These two side reactions would each be expected to be

first order. In a reaction of this order the rate is direct-

ly proportional to the concentration of the substrate, or,

mathematically,

-dc/dt = kc (11)

where c is the concentration of the substrate. If a is the

initial concentration of the substrate, and x is the de-

crease in its concentration after time t, the amount of sub-

strate remaining will be a-x. Then

-d(a x)/dt = k(a x) (12)

-da/dt + dx/dt = k(a X)

Since a is constant,
dx/dt = k(a x)

or, dx/(a x) = k(dt)

Integrating this:
-ln(a x) = kt + C (13)

At t = 0, x = O; -ln(a) = C

Then: ln(a) In(a x) = kt

k = (1/t)ln a = 2.303 log a (14)
a -x t

Since the reaction tubes contained practically 100%

a-pinene, the rate of disappearance of a-pinene may be


60--










calculated at any given tirie, t, by letting a = 100.0 and

(a x) = the percentage of a-pinene unreacted at time t.

For example, 64.1% a-pinene was recovered from the reaction

mixture of Tube No. 6, which had been heated 4920 minutes

at 189.50. Then

k' 2 / 1 9.1Oxl0-5min.-I (15)

If k1 equals the rate of formation of dipentene, and

k2 the rate of formation of allo-ocimene, k' above, the rate

of disappearance of a-pinene, is equivalent to kl + k2:

dx/dt = kl(a x) + k2(a x) = (kI + k2)(a x) (16)


By the above steps it may be derived that

k + k 2.303 log a (17)
1 2 t a x

In order to evaluate kI and k2 separately, consider the

following:

Rate of formation of dipentene = kl(a x)
Rate of formation of allo-ocimene = k2(a x)

Then, at any time, the ratio of the concentrations of di-

pentene to allo-ocimene would be equal to kl/k2 provided no

other complications were involved. In this particular re-

action the allo-ocimene polymerizes rather rapidly, and

the total amount of allo-ocimene that has been formed in

the reaction at any time is equal to the sum of the allo-


-61-









ocimene and the polymer present in the reaction mixture.

so, at any given time,


k. Dipentene
k2 Allo-ocimene + Polymer (18)
Tables 18 and 19, pages 63 and 64, summarize the data

for the tubes which were heated at 189.50 and 204.50, res-

pectively. Column 4 lists the values of k' (= kI + k2)

calculated from the % of a-pinene unreacted. Column 5

lists the calculated total percentage of the compounds

boiling between a-pinene and dipentene. In column 9 are

the values of kl/k2 calculated from the ratios of dipentene

to allo-ocimene plus polymer found in each analysis.


Now k. + ko
andk+k2k
and k, + k2 = k'


Hence


kl + 1

k2(- k + 1
k2


k2 = k_
(kl/k2 + 1)


(19)


(20)


Since k' and k1/k2 are both calculated from the experimental

data, the individual values of kl and k2 can be determined.

The following calculations are made using the average value

of k' and kl/k2

At 189.5- k 8.99x0-5


2.14 + 1.00
S 2.86x10-5 min.-l


3.14


-62-


r-

















Table 18


Summary of Results and Calculations
Temperature = 189.50

% 5 %
Tube Time a-pinene k'xlO other % di- % allo- %
No. min. unreacted min.-1 compds. pentene ocimene polymer k/k2


1230 88.4
1230 88.3

3060 76.5
3060 76.3


5 4920 65.7
6 4920 64.2

40 7800 50.5
41 7800 50.2

7 10680 37.7
8 10680 37.2


15030 25.9
15030 25.8


11 22620 13.9
12 22620 14.0


10.03
10.12

8.76
8.80

8.54
9.01

8.75
8.84

9.14
9.26

9.01
9.02

8.73
8.70


0.8
0.8


7.1
6.7


1.1 15.3
1.1 15.1


1.4
1.4

1.7
1.7

2.1
2.1

2.4
2.4

2.6
2.6


22.2
23.1

32.5
32.9

42.4
42.6

48.8
49.0

57.3
57.4


1.6
3.0

4.1
4.9

5.0
5.5

5.8
6.1

5.6
6.4

6.0
5.8

5.2
5.0


2.3 1.87
1.3 (1.56)

3.0 2.15
2.6 2.01

5.7 2.07
5.8 2.05


9.4
9.2


2.14
2.15


12.2 2.38
11.7 2.35

16.9 2.13
17.0 2.15

21.0 2.18
21.0 2.20


3.9 8.91 2.9
5.0 8.23 2.9
Av. k' = 8.99x101-
Av.Dcv.= 0.33x10-5
% Av.Dev.= 3.7%


63.4
62.9


3.9
3.7
AV.
Av.
% Av.


25.8 2.13
25.5 2.15
kl/k 214
Dev. = 0.08
Dev. = 3.7%


-63-


13 36420
14 36420













Table 19


Summary of Results and Calculations
Temperature = 204.50

% 5 %
Time a-pienne k'xlO other % di- % allo- %
nin. unreacted min.-" corapds. pntene oclmene polymer l/k


440 85.5
440 86.2


825
825


74.1
74.4


19 1200 64.8
20 1200 65.3

21 1500 58.7
22 1500 58.4

23 2040 48.1
24 2040 48.1

25 3060 32.1
26 3060 52.1


27 6060
28 6060

29 16020
50 16020


11.1
11.2


35.6
33.8

36.3
35.9

36.2
35.5

35.5
35.9

35.9
35.9

37.1
37.1

36.3
36.1


0.8
0.8

1.1
1.1

1.4
1.4

1.5
1.5

1.8
1.8

2.2
2.2

2.7
2.7


3.0
3.0
---- -.0
Av. k' =5.9xl0
Av.Dov.= 0.5x10-5
% Av.Dov.= 1.4%


9.1
8.1

16.6
16.1

22.5
22.4

26.5
26.8

33.4
33.5

44.0
44.0

57.5
57.3


64.4
64.2


4.0
4.1

6.6
6.9

7.8
7,6

8.3
8.4

8.5
8.5

8.0
8.4

6.9
6.8


4.9
5.0
Av.
Av.
% Av.


0.6 1.97
0.8 (1.65)


1.6
1.5


2.02
1.92


3.5 1.99
3.3 2.05

4.0 1.99
4.9 2.02

8.2 2.00
8.1 2.02


13.7
13.3


2.03
2.03


21.8 2.00
22.0 1.99

27.7 1.97
27.8 1.96
kl/k" = 2.00
Dev. = 0.025
Dov. = 1.3%


-64-


Tube
No.








and kI = k' k (8.99 2.86)x10-5

AI W 6.13x10-5 min.-1

At 204.50- ko = 3.59x0-4 3.59 X10-4
2.00 + 1.00 3.00

k 1.20xl10-nin.-1

and k kI k2 (3.59 1.20)x10-4

kI 2 2.39xl0-4min.-1


Decrease in Optical Rotation of the Unreactod a-Pinene.-

A study of a rodel of the a-pinene molecule shows that it

is necessary to break at least two carbon to carbon valence

bonds, shift two hydrogen atoms, and then join the bonds in

a different position before it can be changed to the mirror

image. Ouch a step would seem improbable as the molecule

would be broken up completely during the transformation and

apparently could form allo-ocimene more readily than it could

re-form a-pinene.

Attempts have been made unsuccessfully by various

workers to prove or disprove the existence of four optical

isomers of a-pinene since it has two asymmetric carbon atoms.

IIowever the study of the nodel of the a-pinene molecule in-

dicates that these two carbon atoms, the carbon links be-.

tween the six-membered ring and the cyclobutane ring, are

so bound to the molecule that only two optical inomers seem

possible.

Nevertheless, during the heating the optical activity

of the unreacted a-pinene slowly decreases at a rate which


-65-








fits a first order reaction equation with an average deviation

of 9.7% at 189,50 and of 6.5% at 204.50. The constants, meas-

uring the rate of decrease to zero optical rotation of the

a-pinene at the two temperatures, are given in column 5, Tables

20 and 21, pages 67 and 68. They were calculated by the formula:


S2.j5 lo (21)


where a, is the initial observed angle of rotation of the a-

pincne and at is its' observed angle of rotation at time t,

using a 2 din. tube.

The a-pinene from gum turpentine, heated in Tubes No. 40

and 41, which has & negative rotation, also underwent a de-

crease in its optical activity. Its' rate of decrease of

optical activity is of the esme order of magnitude as that

of the d-a-pinene but the determination of the exact value

is subject to large error because of the small rotation of

the sample.

If the recovered material with the lowered rotation is

pure a-pinene, and this seems to be the case, the a-pinene pro-

bably does racemize. In breeding its bonds to form allo-

ocimene thn a-pinone mnoy form an intermediate which could

produce allo-ocincne or recyclize to form a-pinene. Upon re-

cyclizing this intermediate could form either of the optical

isomers with equal ease resulting in a racemic mixture. The

rate constant for the racemization of a-pinene would be one-

half the value of k, since, starting with the pure d-a-pinene,













Table 20


Decrease in Optical Rotation of a-Pinene
Temperature = 189.5


Time
mmin.

1230
1230

3060
3060


ai(2 dn.)


+58.02
+58.26

+58.00
+59.00


4920 +58.02
4920 +57.52

10680 +57.94
10680 +57.94


9 15030
10 15030

11 22620
12 22620

13 36420
14 36420

40 7800
41 7800


+58.12
+57.90

+57.75
+57.75

+58.28
+58.00

-6.49
-6.49


at(2 dm.)


+56.82
+57.00

+54.75
+54.79

+52.25
+53.00

+47.38
+47.39

+43.00
+42.66

+36.00
+35.87

+21.00
+20.46

-5.92
-5.90


kixlO5
min. -

1.7
1.8

1.9
1.9

2.1
1.7

1.9
1.9


2.0
2.0

2.1
2.1

1.4
1.4


k x106


8.5
8.9

9.5
9.3

10.7
8.3

9.4
9.4


10.0
10.2

10.5
10.6

7.2
7.0


(1.2) (6.0)
(1.2) (G.1)
Average = 9.3
Av. Dev.= 0.9
% Av. Dev.= 9.7%


-67-


Tube
No.

1
2

3
4

5
6

7
8














Table 21


Decrease in Optical Rotation of
Temperature = 204.50


a-Pinene


Tube
No.


Time
min.


15 440
16 440


825
825


19 1200
20 1200

21 1500
22 1500

23 2040
24 2040


3060
3060


27 6060
28 6060


ai(2 dm.)


+58.00
+58.00

+58.00
+58.00

+57.98
+57.98

+57.88
+57.95

+57.88
+57.88

+58.12
+58.12

+57.45
+57.76


at(2 dm.)


+56.02
+56.13

+54.33
+54.49

+52.60
+52.31

+50.57
+50.78

+48.50
+48.78

+45.75
+45.85

+32.05
+33.35


kxlO5
min. -1

7.9
7.5

7.7
7.6


8.1
8.6

9.0
8.6

8.7
8.4

7.8
7.8


k3xlO6
min.

4.0
3.7

3.9
3.8


4.1
4.3

4.5
4.3

4.4
4.2

3.9
3.9


9.6 4.8
9.1 4.6
Average = 4.2
Av.Dev. = 0.27
% Av. Dev.= 6.4%


-68-








only half of the a-pinenc molecules must change their rotation

in order to form a raccmic nixture(26,28). The racemization

rate constants of a-pinene, k3, are given in column 6, Tables

20 and 21.


Polymerization of Allo-ocimone. From the data previously ob-

tained, it would seem that allo-ocimnen should form a dimer

by a second order reaction. Preliminary experiments indicated

that the polymer from pure allo-ocimene was more homogeneous

than that formed from the products of the a-pinene isomerizations.

The former boiled at 173-176oC. (9 mm.) and had a refractive

index range (250) of 1.5208-1.5212. Three molecular weight

determinations of this sample of polymer gave values of 260,

260 and 262.

In studying this reaction, the sealed tubes of allo-ocimene

were heated for varying lengths of time and then were opened

and the allo-ocimene was separated from its diner in the spiral

screen analytical columns previously described. A known weight

of the mixture was taken for the separation of the components

and the polymer remaining in the flask was weighed. The % pol-

ymer formed was calculated by dividing the weight of polymer

by the total weight of mixture taken. The data are given in

Tables 22 and 23, pages 74 and 75. The n25D for the allo-oc-

imene recovered from each tube is given in column 4 of these

tables. In general this value tends to decrease for those

tubes heated for the longer times. This decrease in refractive


-69-







index is probably due to the formation of small amounts of a-

and B-pyronene from the allo-ocimene. However, a complete in-

terpretation of these data must await further study.

Unexpectedly, it was found that the dimerization does not

go to completion. This suggested either that the allo-ocimene

contained a component that will not polymerize or that the dimcr

was in equilibrium with its monomer. The recovered allo-oc-

imene (2 gm.) from Tubes No. 66 and 67 was heated 24 hours at

189.50. The product was almost completely polymer, b.p. (10 mm.)

170-178, n25D 1.5190. The allo-ocimone in Tube No. 68 was

that recovered from tubes No. 58-59. Thus it is seen that the

unreacted portion may be dimerized if separated from the dimer

already formed.

Sealed tubes of the recovered polymer were heated to see

if allo-ocimene could be obtained from it. These data are given

in Table 24, page 76. The polymer recovered from Tube No. 90

was sealed in Tube No. 91 and heat. for the same length of time.

The somre amount of allo-ocimeno was recovered in each case.

There can be no doubt that this is an equilibrium reaction.

The rate constants for the formation of the dimer, calcu-

latec from formula (30), derived from the following considerations.

The reaction in of the type
k4
A + A B
k5

If no B is initially present, then at any time,

dx/dt = k4(a x)2 k5x (22)

where a is the initial concentration of A in moles/liter and x


-70-







is the number of moles/liter reacted at time t.


At equilibrium,

where q is the

Then k5

and from (22)-

dx/dt

dx/dt =

dx/dt =

dE/dt -=

dch/dt t

d:/dt =

dx/dt

Then- qdx
(q x)(as


k4(a q)2 = k5q (23)

amount of A reacted when equilibrium is reached.

= k4(a q)2/q



k4(a- x)2 k4(a q)2x/q (24)
4((a- x)2 (a q)2(x/q))

k4(a2 Sax + 2 (x/q)(a2 2aq + q2))

4(a2 2ax + x2 a2x/q + 2ax xq)

k4(a2(l x/q) + x(x q))

k4((a2/q)(q x) x(q x))

(k4/q)(q x)(a2 xq) (25)

S k4dt (26)


- Axj


SolvinC the left hond term of (26) by partial fractions,


(q x)(a xq) (q x)

where 1I and N are constants. Then

q = .1 (a2 xq) +

q = Ma2 Mxq +

Equating coefficients of like powers

q = Ma2 + Nq

0 -Mq N

q = Ma2 Mq


M = q/(a2 q2)

Therefore- a


and


(q x)(a4 xq) (a


+ (.-- xq)


(27)


N(q x)

Uq Nix

of x,


and


N = -Kq


S -q2/(a2 q2)

2 q2
- qi)(q x) (a;: q)(a-xq)


-71-


l~








q0 dx _2 dx
aZ q x) q) (O xq)


= k4 dt


= k4t + C


Combining terms:

2,303q2 lo,(-2 x)
a q (q x)

At t = 0, x = 0 and C =


So (28) becomes

k = 2.303 .
4 t a


- -k4t + C


Since second order reaction constants involve a concen-

tration unit it is necessary to know the density of the allo-

ocimene at the temperatures at which the reaction occurred.

To determine this, 35 cc. of allo-ocimene were placed in a

tube of 1 cm. inside diameter and scaled. The tube was placed

in the oil bath at 204.50 for ten minutes and the level of the

allo-ocimene in the tube marked. The liquid was then cooled

to 250 and this level marked. After the tube was broken and

the liquid removed, the increase in volume was found to be

19% by determining the weight of water in the tube when filled

to each mark. Since the allo-ocimene has a d5 of 0.805 it

follows that 04.5 = 0.805/1.19 = 0.68. By interpolation
189.5
d4 is estimated to be 0.69.

The initial molar concentration, a, of allo-ocimene at

204.50 = dxlO0/m.w. = 680/156 = 5.0 moles/liter.


-72-


(28)


(29)



(30)


Q (-in(q-x))- 2 ( -1/q)ln(a2 xq)
(a q) (a; q-)(


2303q .g P
a q < q


o .loC(a2 xq)
- qA a'(q x)







At 189.50 this value is 690/13G = 5.1 moles/liter.

The number of moles/liter of allo-ocimene reacted

at equilibrium, q, equals (ax% allo-ocimene reacted at

eLuilibrium). At 189.5" the average of Tubes No. 66,07,93

and 94 indicate that 899 allo-ocimono had reacted at equil-

ibrium. Thus q = 5.0(0.89) = 4.5 moleo/liter.

At 204.50, the average of Tubes No. 80,81, 95, and 96 in-

dicate that 88% allo-ocimene had reacted at equilibrium.

IHnce, at 204.50, q = 0.88(5.1) = 4.5 moles/liter.

The calculation of l:4 by equation (30) may be illus-

trated with the data for Tube No. 54, which, when heated

408 minutes at 189.50 yielded 64% polymer. The units of

concentration in the numerator and denominator cancel in

the log term and fractions may be substituted directly in

this part of the equation, vwheie a = 1.00, q 0.89, and

x = 0.04.
2.303. 4.5 log0.89(1 0.89(0.64))
4 408 (5.1) (4.5JF1o 1.0(0.89 0.64)

k4 = 8.1xlO-4 liters/nole-min.
The values of k4 are given in column 8, Tables 22 and 23,

pages 74 and 75. From this it may be concluded that the

date for the reaction hss been correctly interpreted.

Several Diels-Alder reactions have been found to be rever-

,ible bimolecular associations of the same type as the dimer-

ization of allo-ocimene. All of these Diels-Alder reactions

involve "a 1:4 addition of an ethenoid to a butadienoid system"

(41). The dlmerization of allo-ocimene is quite probably the


-73-











Table 22


Reversible Polymerization of Allo-ocimene
Temperature A 189.50


a = 5.1 moles/liter


Allo-
Time ocimene
Tube Heated Recovered
No. min. hr. n25D


q = 4.5 moles/liter


Wt.
Mixture
jm.


Vt.
Polymer
ge--


Polymer


k ix04

mole -r.:in.


108 1.80 1.5416
108 1.80 1.5417

254 4.23 1.5415
254 4.23 1.5419

408 6.80 1.5411
408 6.80 1.5415

720 12 1.5396
720 12 1.5410


58-59 1020
68 1020


1440 24
1440 24


17 1.5412
17 1.5392


1.5588
1.5410


3990 66.5 1.3355
3990 GG.5 1.5577

6780 113 1.5413

8'20 137 1.5381


66 13250 221 1.5360

67 14760 246 1.5340


15.8
16.6

15.9
15.9

16.3
16.1

16.4
16.3

32.0
5.5

16.3
16.4

15.7
15.7

16.0

15.5

15.6

15.7


5.4
5.3

8.5
8.4

10.4
10.4

12.4
12.3

25.6
4.2

13.7
13.9

13.7
13.7

14.0


13.8

14.1


9.1
7.9

8.5
8.3

8.1
8.5

8.7
8.7

7.8


8.1
8.9


87
88

87.5

86.5

88.5


90
Average -
Av. Dev.=
% Av. Dov,=


-74-


8.4x10-4
0.35
4.2%















Table 23


Reversible Polymerization of Allo-ocimene
Temperature 204.50


a 5.0 moles/liter

Allo-
Time ocimene
Heated Recnvered
min. hr. n"?


q = 4.5 moles/liter


Wt.
Mixture
ntf.


V!t.
Polymer
Me.


Polmer


L4x104
liters/
mole-min.


50 0.83
50 0.83

130 2.17
130 2.17


1.5419
1.5418

1.5415
1.5420


72 185 3.08 1.5413
73 185 3.08 1.5411


285 4.75
285 4.75

395 6.58
395 6.58

640 10.67
640 10.67


80 3480 58

81 5700 95


1.5389
1.5395

1.5393
1.5400

1.5360
1.5374

1.5263

1.5260


13.7
14.9

12.9
13.6

15.4
15.5

14.4
14.9

15.3
14.4

14.9
15.4


14.4


4.4
4.9

7.0
7.4

10.0
9.7

10.2
10.4

11.5
10.8

12.0
12.4

11.9

12.5


87.5


87
Average
AT. Dev.
% Av. Dev.


-75-


Tube
No.


= 22
= 1.5
= 6.8%


















Table 24


Decomposition of Polymer


Allo-
oc imene
Recovered
n25D


Wt.
Mixture


Wt.
Polymer
Fip. Polymer


(Temperature = 189.50)


1.5396
1.5350

1.5423

1.5300
1.5415


17.3
13.8

16.6

14.5
14.8


15.9
12.7

14.9

13.0
13.1


(Temperature = 204.50)


1.5275
1.5267


17.2
18.2


15.2
16.0


-76-


Tube
No.


Tine
Heated
hr.


148
148

239

390
390


92
92

90

89.5
88.5


95
135


88.5
88






same type of bimolocular association. It is believed that

the allo-ocimene molecule furnishing a single double bond

to the ring formation of the dimer reacts only at the middle

double bond. If it should react at either of the end double

bonds a conjugated system would be left free to react further

and a chain polymerization would be expected to occur.

By determining the equilibrium constant of the reaction,

the value of k5, the rate of decomposition of the dimer to

allo-ocimene may be calculated from the equation Ke. =
eq.
k4/k5. The density of the equilibrium mixtures at 250

in Tubes No. 66 and 80 was found to be about 0.875. To

determine the density of the equilibrium mixture at 204.50

the method described for the determination of the density

of allo-ocimene at this temperature vas used. It was found

to be 0.74. By interpolation, the density of the equilibrium

mixture at 189.50 was calculated as 0.75.


K = (polymer)
eq. (allo-oclmene)"

At 189.50 0.89(0.75)x0ooo
Keq. 272 = 6.7 liters/mole
(0.11(0.75)x100ooo)2
136

k5 = k4/Kq. 8.4x10-4/6.7 1.25x10-4min.-1

Similarly, at 204.50,

Keq. 5.6 liters/mole

k5 = k4eq. 2.2x10-3/5.6

k5 = 3.9xl0'-4in.-1


-77-







The general form of the Arrhenius equation, expressing

the relation of the reaction velocity and temperature is

d In k E
&V RT;
--...T- = r (31)

in which k is the reaction rate constant, E is a constant

termed the energy of activation, R is the molar gas con-

stent, and T is the absolute temperature. Integrating

this equation between the limits of T2 and T1,

Sko E To Ti(
log- 2.303R (32)

where k2 is the reaction rate constant at T2 and k1 is

the reaction rate constant at T1. Using the value of

k204.5/k189.5 for each reaction, the energies of activation
were calculated. The data are recorded in Table 25, page 79.

Equation (31) may be integrated without limits:

In k = -E/RT + In s (33)

where In s is the integration constant.

Then k se-E/RT (34)

For gaseous reactions it has been shown that e-E/RT

is an expression of the fraction of the molecules in the

reaction system having energy equal to or greater than the

activation energy E(42). For bimolecular reactions a refers

to the number of molecules colliding and usually has a

value of about 1010 or 1011 when the rate constants are ex-

pressed in liters/mole-min. For unimolecular reactions s us-

ually has a value of about 1014 or 1015 min.-1 Attempts have

been made to associate s for these unimolecular reactions


-78-








with the frequency of vibrations in a molecule(43).

The values of log s, calculated at 189.50 are given

in column 3, Table 25. All of the reactions have values of

s following those general rules except the decomposition

of the dimer to allo-ocimene. The large error involved

in the determination of the rate constants for this reaction

makes the deviation in the value of s of doubtful signifi-

canco. It does, however, suggest that the unimolecular

decomposition of the dimer occurs through a mechanism

such that the second order rate of formation of the acti-

vated complex i.. hot' as rapid as the unimolecular de-

composition of the activated complex to form allo-ocinene.



Table 25

Enorgios of Activation


Reaction

Raccr.ization of a-pinene

a-pinene .m..dipentene

a-pinene --- allo-oc ieno

S(allo-ocimene) ---dimer

dimer ---2 (allo-ocimone)


EAnt.(csls.) log 8

44,150 15.8

39,850 14.6

42,000 15.3

28,200 10.2

31,200 10.8


-79-








Cummary.- From the data presented in this chapter the

over-all reaction appears to be:


d-a-pinene
l-a-pinene


dl--pin
-_ dl-a-pinene


allo-ocimen I



dimer a-pyronene
B-pyronene


dipentene


Table 26

Sunmmary


kl(min."1)

k2(min."1)

k3(min.l1)

k4(liters/
mole-min,

k5(min.'1)


Rate
Constant
x105
(189.50)

6.13

2.86

0.93

84
.)

12.5


Rate
Constant
1056
(204.50)

23.9

12.0

4.2

220


39


-80-


Energy
of
Activation

39,850

42,000

44,150

28,200


31,200


log a

14.6

15.3

15.8

10.2


10.8







Bibliography


(1) Palkin and Co-workers, U.S.D.A. Technical Bulletin
No. 276 (1932).

(2) Selker, Burk and Lankelma, Ind. Eng. Chem., Anal. Ed.,
12, 352 (1940).
(3) Lecky and Ewell, ibid., 12, 544 (1940).

(4) Robinson and Gilliland, "The Elements of Fractional
Distillation," 129, McGraw-Hill (1959).

(5) Beatty and Calingaert, Ind. Eng. Chem. 26, 504, 904 (1934).

(6) Bromiley and Quiggle, ibid., 25, 1136 (1933).

(7) Stallcup, "Terpene Studies Ia Thesis, University of
Florida, (a) 5-8; (b) 23-24 (1942).

(8) Tongberg, Quiggle and Fenskc, Ind. Eng. Chem. 26,
1213 (1934).

(9) Ward, U.S. Bur. Mines, Tech. Paper 600 (1939).

(10) Peters and Baker, Ind. Eng. Chem., 18, 69 (1926).

(11) Morton, "Laboratory Technique in Organic Chemistry,"
80, McGraw-Hill (1938).

(12) Whitmore, Fenskc, Quiggle, Bernstein, Carney, Lawroski,
Popkin, Wagner, Wheeler and Whitaker, J. Am. Chem.
Soc., 62, 795 (1940).

(13) Bain, Private communication.

(14) Pclkin and Co-workers, U.S.D.A. Technical Bulletin No.
590 (1937).
(15) atermnan, Van't Spijker and Van Westen, Rec. tray. chim.
48, 1191 (1929).
(16) Dupont, Beilstein Suppl., Vol. V, 77-79 (1930).

(17) Hershberg and Huntress, Ind. Eng. Chemo Anal. Ed.,
5, 344 (1933).

(18) Auwers, Ann., 387, 240 (1912).


-81-







(19) Black and Thron3on, Ind. Eng. Chem., 26, 66 (1934).

(20) Dupont, "Les Essences de Tercbonthine," Gauthier
Villars, Paris (1936).

(21) Lange, "Handbook of Chemistry," 4th Ed., 1430, Hand-
book Publishers (1941).

(22) Lange, ibid., 1445-1446.
(23) Sameshima, J. Am. Chem. Soc., 40, 1489 (1918).

(24) Berthelot, Ann. Chim. (iii) 37, 223; 39, 9 (1853).

(25) Wallach, Ann. 227, 282 (1885).

(26) Smith, J. Am. Chem. Soc. 49, 43-50 (1927).
(27) Conant c.nd Carlson, ibid., 51, 5464-9 (1929).

(28) Kassel, ibid.,52, 1935 (1930).

(29) Thurber and Johnson, ibid., 52, 786-92 (1930).

(30) Arbuzov, J. Gen. Chem. (U.S.S.R) 3, 21 (1933); Ber.
67B, 563 (1934).

(31) Dupont and Dulou, Compt. rend. 201, 219 (1935).

(32) Goldblatt and Palkin, J. Am. Chem. Soc. 63, 3517-3522
(1941).

(33) Thurber and Thiclke, ibid., 53, 1030 (1931).

(34) Tilden and Shenatone, J. Chem. Soc. 31, 761 (1877).

(35) Tilden, ibid. 85, 760 (1904).

(36) Simonsen, "TheTerpenes"' Vol. II, 151 Cambridge Press
(1932).

(37) Wallach, Ann. 225, 304, 318 (1884).
(38) Dupont and Dulou, Atti Xo Congr. Intern Chim., 3,
125 (1939).
(39) Harries, Bcr. 35, 3256 (1902).

(40) Goldblatt, Private communication.


-82-







(41) The Faraday Society "Reaction Kinetics" 129-137,
Gurney and Jackson, London (1937).

(42) Gotman and Daniels, "Outlines of Theoretical Chemistry,"
6th ed. 341, John Wiley and Sons, Inc. New York
(1937).

(43) Daniels, "Chemical Kineticj," 18, Cornell University
Press, Ithaca, New York (1938).


-83-























Appendix








Table 27


Plate Determination

Column Refractive Index Refractive Index Number
No. of of of
Sample in Head Snmple in Kettle Plates

1 1.4005 1.4130 22

2 1.3970 1.4110 24

3 1.4045 1.4154 21

7 1.5888 1.4164 70

8 1.3910 1.4196 64




Table 28

Determinations of Operating Holdup

Column Woitght Text Initial % Final % Operating
No. Mixture, g. Stearic Acid Stearic Acid Holdup, ml.

1 24.7 10.2 17.5 11.4

2 19.7 9.75 21.0 12.1

3 35.0 10.7 17.6 15.3

8 23.8 10.5 15.9 9.1


-85-














Table 29


Fractionation of Commercial
a-Pinene in Column 7


Fraction
No.



1
2
3-17
18-38
39
40
41
42
43-44


Volue
Fraction
ml.


84
66
1550
1495
75
47
75
60
80


-86-


n25D


1.4628
1.4630
1.4631
1.4632
1.4638
1.4671
1.4762
1.4767
1.4768














Table 30


Fractionation of a Mixture of
a-Pinene, Campheno ond B-Pinone in Colmmn 7


Fraction Volume
No. Fraction n25D
ml.


1 3 1.4605
2 65 1.4630
3-13 197 1.4631
14 30 1.4632
15 25 1.4633
16 15 1.4636
17 15 1.4639
18 25 1.4641
19 8 1.4649
20 18 1.4657
21 30 1.4679
22 20 melts above 25
23-25 120 melts 46-48
solidifies 45-440
26 10 melts above 250
27 30 1.4721
28 15 1.4741
29 15 1.4754
30 15 1.4757
31-34 78 1.4768


-87-












Table 31


Fractionation of a Mixture of
Carbon Tetrachloride and Cyclohexane in Column 8

CCL4: n D 1.4531 Cyclohexane: n25D 1.4230


Fraction
No.


Volume
ml.


25D
n D


BP(762 mm.)
CP.
oC.


1.4492
1.4496
1.4531
1.4530
1.4521
1.4527
1.4517-1.4519
1.4522-1.4528
1.4521
1.4516
1.4509
1.4499
1.4482
1.4476
1.4478
1.4435
1.4421
1.4388
1.4350
1.4322
1.4298
1.4272
1.4252
1.4244
1.4240
1.4232
1.4230
1.4229
1.4228
1.4243


77.1
77.1
77.1
77.1
77.1
77.1
77.1
77.1
77.1
77.1
77.1
77.1
77.1-77.3
77.4
77.4-77.8
77.8-78.0
78.0-78.1
78.1-78.5
78.5-79.0
79.0-79.4
79.4-80.0
80.0-80.5
80.5-80.7
80.7-80.8
80.8
80.8
80.8
80.8
80.8
ResidMe


-88-


1
2
3
4
5
6
7-8
9-13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31-32
33-35
36
37-40
41


2.0
2.0
3.0
2.0
2.0
2.0
4.1
10.0
2.0
2.0
2.1
1.6
1.0
1.0
0.8
1.2
0.8
1.1
0.9
1.0
0.4
1.7
1.4
1.2
0.8
3.0
7.1
3.0
7.4
2.4















Table 32


Fractionation of a Mixture of
a-Pinene and B-Pinene in Column 8


Fraction
No.



1
2-5
6
7-9
10
11-12
13
14
15
16
17
18
19
20-26


Volume
Frnotion
ml.


1.0
7.0
1.5
3.5
1.3
2.8
1.0
0.5
0.7
0.5
0.9
0.3
0.4
12.3


-89-


25D
n D


1.4632
1.4631
1.4632
1.4633
1.4637
1.4633
1.4650
1.4708
1.4735
1.4757
1.4762
1.4766
1.4766
1.4767












Table 33


a-Pincne


Fraction
No.

1
2-3
4
5-7
8-11
12
13
14-17
18
19
20
21
22
23-26
27
28
29-30
31
32
33
34
35


Distillation of a Mixture of
and Commercial Dipentene in Column 8


Volume
ml.

2.0
4.1
2.0
6.0
8.0
2.0
2.0
8.0
2.0
2.0
1.0
1.5
1.4
8.2
2.0
2.0
4.0
2.0
2.0
2.0
2.0
2.0 .


29
n D

1.4612
1.4617
1.4616
1.4617
1.4618
1.4617
1.4618
1.4617
1.4617
1.4491
1.4592
1.4677
1.4719
1.4732
1.4731
1.4729
1.4728
1.4726
1.4726
1.4725
1.4721
1.4719


(20 mm.)
B.P.
0C.
53.0-53.5
53.5
53.5
53.5
53.5-53.3
53.3
53.3
53.3
53.3-55
55-66
66-68.5
68.5-?
69.2-70.0
69.5-70.3
70.0-70.5
70.5
70.0
70.0
71.0
71.0
71.0
71.0


-90-












Table 34


Fractionation of Terpene Alcohols in Colwnn 8


Fraction
No.


Volume
Fraction


2.0
2.0
2.2
6.2
2.0
4.0
15.0
1.8
1.0
1.8
1.7
2.7
1.4
0.6
1.0
0.7
0.8
0.9
0.8
1.4
4.0
2.7
1.6
about 0.5


1.4606
1.4608
1.4608
1.4610
1.4612
1.4603
1.4610
1.4632
1.4643
1.4650
1.4653
1.4660
1.4660
1.4713
1.4701
1.4803
1.4802
1.4888
1.4902
1.4923
1.4928
1.4926
1.4931
1.4928


OC.
106-106.5
106.5-107
107
107
107
107-108
108-110
110-116
116-118
118
118
118-122
122-123.5
123.5-126
126
126-126.5
126.5
126.5-127
127-128
128
128
128-129
129-129.5
Residue


-91-


25
n D


1
2

4-5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25










Table 35


Analysis of Tube No. 1
(Heated at 189.50C. for 20.5 hours)


Wt. B.P.
Fract. Fr. (19
No. a. im.) n 5D
1-4 35.6 51.5 1.4631
5-8 23.7 51.6 1.4632
9 3.2 51.6 1.4633
10 2.4 --- 1.4640
11 0.7 --- 1.4671
12 1.1 ---- 1.4732
13 1.1 ---- 1.4710
14 1.3 ---- 1.4761
15 1.0 ---- 1.4805
16 0.4 ---- 1.4870
17 0.4 ---- 1.5140
Corr. 0.5 1.5415
18 1.6polymerl.5140
Totals 73.0


Total % a- % di-
Wt. pinene pentene
48.80 48.80
32.45 52.00 0.45
4.38 4.26 0.12
3.29 2.87 0.42
0.96 0.42 0.54
1.51 1.45
1.51 1.49
1.78 1.63
1.37 1.17
0.55 0.42
0.55 0.21
0.66


2.19


88.4 7.9


% allo- %
ocimene polymer





0.06
0.02
0.15
0.20
0.13
0.34
0.66
2.19
1.6 2.2


Table 36

Analysis of Tube No. 2
(Heated at 189.50C. for 20.5 hours)

B.P.
(18 Total %a- % di- allo- %
am.) n25D Wt. pinene pentene ocimene polymer
50.5 1.4633 12.50 12.14 0.36
50.5 1.4631 61.50 61.50
50.5 1.4632 11.87 11.70 0.17
--- 1.4635 2.04 1.92 0.12
53-
68.8 1.4668 2.04 0.98 1.06
69.0 1.4703 4.60 4.60
70-


85 1.4868
85 1.5359
1.5415
pol. 1.5130


1.28
2.30
0.62
1.28


0.99
0.18


88.3 7.5


0.29
2.12
0.62
1.28
3.0 1.3


-92-


Fract.
No.
1
2-4
5-6
7
8

9-10
11

12
Corr.
13
Totals


Wt.
Fr.
gms.
9.8
48.2
9.3
1.6
1.6

3.6
1.0

1.8
0.5
1.0
78.4











Table 37


Analysis of Tube No. 3
(Heated at 189.50C. for 51 hours)


Fract.
No.
1-4
5
6
7


VWt.
Fr.
grias.
41.5
11.7
4.8
2.1


8-10 10.4
11 1.5


12 2.5

Corr. 0.5
13 2.3
Totals 77.3


B.P.
(20.5
mm.)
52.9
53.0
53.4
54-


72
72


n"5D
1.4631
1.4632
1.4634


%
Total
Wt.
53.70
15.14
6.21


72 1.4651 2.72
!.0 1.4702 13.45

87 1.4918 1.94


87-
88.2 1.5386
1.5415
pol. 1.5169


3.23
0.65
2.97


% a- % di-
pinene pentene
53.70
14.92 0.22
5.95 0.26


% allo- %
ocimene polymer


1.96 0.76
13.45


1.64

0.13


0.30

3.10
0.65


2.97
76.5 16.4 4.1 3.0


Table 38

Analysis of Tube No. 4
(Heated at 189.50 for 51 hoars)


BePe
(20.5
mmr.) n25D
52.9 1.4631
52.9 1.4632
53.5 1.4634
54-
72 1.4651
72.0 1.4701
72.0 1.4703
72-


Total % a- % di- % allo- %
Wt. pinene pentene ocimene polymer
56.70 56.70
12.34 12.16 0.18
6.37 6.10 0.27


1.82
4.81
4.81


77 1.4706 6.33
1.0 77-


87 1.5220
88 1.5410
1.5415
pol. 1.5162


1.30
3.25
0.65
2.60


1.31 0.51
4.81
4.81

5.31 0.02

0.35 0.95
0.02 3.23
0.65
2.60
76.3 16.2 4.9 2.6


-n-
, 0-


Fract.
No.
1-4
5
6
7


Wt.
Fr.

43.7
9.5
4.9
1.4


3.7
3.7
4.1


12
Corr.
13
Totals


2.5
0.5
2.0
77.0






Table 39


Analysis of Tube No. 5
(Heated at 189.50C. for 82 hours)


Wt.
Fract. Fr.
No. g=S.
1 7.7
2-3 16.3
4-6 15.5
7-8 4.0
9 1.4
10 1.5


0.2
0.2
2.7


14-17 9.2
18 2.8
19 0.3
20 1.9
21-22 1.9
Corr. 0.5
23 4.0
Totals 70.2


B.P. %
(19 Totnl % a-
inm.) n25D WVt. pinene
51.6 1.4630 10.97 10.97
51.6 1.4631 23.20 23.20
51.8 1.4632 22.10 21,79
51.9 1.4633 5.71 5.55
--- 1.468 200 1.80
52.5
-56 1.4647 2.28 1.77
--- 1.4649 0.28 0.21
--- 1.'4689 0.28 0.05
66-


69 1.4695
69.3 1.4702
---- 1.4713
1.4758
---- 1.5106
87 1.5400
1.5415
pol. 1.5130


3.85
13.10
4.00
0.43
2.71
2.71
0.71
5.71


% di- % allo-
pentene ocimene polymer


0.31
0.16
0.20

0.51
0.07
0.23


0.38 3.47
13.10
3.94
0.40
1.17
0.05


65.7 23.6


0.06
0.03
1.54
2.66
0.71

5.0


5.71
5.7


Table 40
Analysis of Tube No. 6
(Heated at 189.50C. for 82 howrs)


B.P.
(19
mm.)
51.4
51.6
62.0
52.6
53.5

54
70-


Total
n25D Wt.
1.4631 18.80
1.4632 36.40
1.4634 1.95
1.4637 3.76
1.4642 2.50
1.4647 0.28
1.4650 2.65


70.1 1.4702
---- 1.4708
---- 1.4920
1.4888
86 1.5365
---- 1.5387
1.5415
pol. 1.5170


17.27
2.50
1.53
1.81
2.23
1.81
0.69
5.85


% a- % di- % allo- %
pinene pentene ocimene polymer
18.80
35.88 0.52
1.87 0.08
3.44 0.32
2.11 0.39
0.22 0.06
1.94 0.71


17.27
2.48
1.06
1.34
0.15
0.07


64.2 24.5


0.02
0.47
0.47
2.08
1.74
0.69
5,85
55 5.8
5.5 5.8


-94-


Fract.
No.
1-3
4-8
9
10
11
12
13
14-17

18
19
20
21
22
Corr.
23
Totals


Wt.
Fr.

13.5
26.1
1.4
2.7
1.8
0.2
1.9
12.4

1.8
1.1
1.3
1.6
1.3
0.5
4.2
71.8










Table 41


Analysis of Tube No. 40
(Heated at 189.50C. for 130 hours)


B.P.
(20o.5
rui.) n25D
52.5-
52.8 1.46635
52.9 1.4629
53.0 1.4631
53-71 1.4663
72.0 1.4702
72-88 1.4980
88.0 1.5403

pol. 1.5207


Total % .-
V,'t. pinon


6.29
7.46
34.58
4.06
31.20
1.83
4.48
0.65
9.43


6.29
7.46
34.58
2.23


% di- % &llo- %
e pentene ocimonc polyner


1.83
31.20
1.11
0.06


\Vt.
Fr.

4.8

5.7
26.4
3.1
23.8
1.4
3.5
0.5
7.2
676.4


0.72
4.42
0.65
9.43
5.8 9.4


Table 42

Analysis of Tube No. 41
(Heated at 189.50C. for 130 hours)


Vit. B.P.
Fr. (20.5
fI3. Im.
7.0 52.5-
52.8
9.1 52.9
17.8 53.0
3.6 55.0
2.4 53-
71.5
2.2 71.5-
71.9
22.2 71.9
4.3 87-88
0.5
7.0 pol.
76.1


%
Total % a-
n25D Wt. ninene


1.4636
1.4630
1.4631
1.4G62


9.20
11.95
23.40
4.73


9.20
11.95
23.40
4.66


1.4680 3.16 0.98


1.4701
1.4703
1.5380
1.5415
1.5200


2.89
29.20
5.65
0.66
9.20


% di- % allo- %
pentene ocimene polymer




0.07

2.18


2.89
29.20
0.25


5.40
0.66


9.20
50.2 34.6 6.1 9.2


-95-


Fract.
No.
1

2
3-6
'I
8-9
10
11
Corr.
12
Totals


50.5 34.2


Fract.
No,
1

5
3
4
5

6

7-9
10
Corr.
11
Totals







Tnble 43


Analysis of Tube No. 7
(Heated at 189.50C. for 178 hours)


7t.
Fract. Fr.
No. grs
1 4.0
2 5.3
3-4 18.7
5 4.9
6 1.8


7-8
9
10

11
Corr.
12
Totals


24.7
2.5
1.2

5.4
0.5
9.3
7C, S


B.P.
(20
m_._ n) 5D
52.5 1.46-57
52.8 1.4638
52.8 1.4640
54.0 1.4644
58-
71 1.4702
71.5 1.4710
71.5 1.4711
72-
86.51.4964
86-9 1.5354
1.5415
pol. 1.5208


Total % a- % di-
Wt. pinene pantonc
5.24 4.80 0.44
6.94 6.25 0.69
24.50 21.40 3.10
6.42 5.25 1.17


2.36
32.40
3.28

1.57
4.45
0.66
12.18


2.36
32.08
3.25


0.99
0.49


37.7 .5-


% allo- %
ocimene polymer






0.32
0.03

0.58
3.96
0.66
12.18
5.6 12.2


Table 44

Analysis of Tube No. 8
(Heated at 189.50. for 178 hours)


Vt. B.P.
Fr. (20
gns. mm.
2.8 52.4
4.1 52.7
6.4 52.7
12.1 52.7
6.0 --
1.3 54-62
0.3 ---
1.4 62-71
28.0 71.5
4.5 66-89
0.5
8.9 pol.
76.3


Total
n25D ,t.
1.4637 3.67
1.4636 5.37
1.4639 8.38
1,4640 15.85
1.4643 7.86
1.4668 1.70
1.4655 0.39
1.4708 1.84
1.4710 36.70
1.5340 5.90
1.5415 0.66
1.5197 11.67


% a- % di- % allo- %
pinene pentene ocimene polymer
3.36 0.31
4.99 0.38
7.43 0.95
13.85 2.00
6.53 1.33
0.81 0.89
0.26 0.13
1.82 0.02
36.29 0.41
0.60 5.30
0.66
11.67
37.2 44.7 6.4 11.7


-96-


Fract.
No.
1
2
3
4-5
6
7
8
9
10-11
12
Corr.
13
Totals









Table 45


Analysis of Tube No. 9
(Heated at 189.50C. for 250.5 hours)


Wt. B.P.
Fract. Fr. (18 Total % a-
No__. ia. mm.1 n25D Wt. pinen
1 6.1 50.6 1.4632 8.25 8.14
2 4.8 50.6 1.4631 6.50 6.50
3 2.8 50.6 1.4632 3.79 3.74
4 3.2 51.0 1.4634 4.33 4.15
5 4.3 51-64 1.4667 5.82 2.92
6 1.9 64-67 1.4690 2.57 0.43
7-12 32.0 68 1.4702 44.50
13 0.9 --- 1.4886 1.22
14 4.0 85-86 1.5355 5.42
Corr. 0.5 1.5415 0,68
15 12.5 pol. 1.5191 16.92
Totals 73.9 25.9


% di-
e penteno
0.11

0.05
0.18
2.90
2.14
44.50
0.91
0.44


% allo- %
ocimene polymer


0.31
4.98
0.68


16.92
51.2 6.0 16.9


Table 46

Analysis of Tube No. 10
(Heated at 189.50C. for 250.6 hours)


Wt. B.P.
Fr. (18
gsa3. mm.)
7.5 50.5
4.8 50.6
5.0 51.0
3.8 51-67
1.6 67-68
28.3 68.0
1.2 68.0
1.3 68.0
1.3 68.0
4.0 85-86
0.5
12.1 pol.
71.4


n25D
1.4633
1.4634
1.4637
1.4670
1.4689
1.4703
1.4715
1.4706
1.4706
1.5547
1.5415
1.5191


Total % a- % di- % allo- %
Wt. pinene pentene ocimene polymer
10.50 10.20 0.30
6.72 6.44 0.28
7.00 .6.41 0.59
5.32 2.39 2.93
2.24 0.41 1.83
39.70 39.70
1.68 1.65 0.03
1.82 1.81 0.01
1.82 1.81 0.01
5.61 0.53 5.08
0.70 0.70
16.95 16.95
25.8 51.4 5.8 17.0


-97-


Fract.
No.
1
2
3-4
5
6
7-11
12
13
14
15
Corr.
16
Totals




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs