Citation
Single Site Catalyst for Novel Ethylene/ Propylene Polyolefins

Material Information

Title:
Single Site Catalyst for Novel Ethylene/ Propylene Polyolefins
Creator:
Alqahtani, Khalid M
Publisher:
University of Florida
Publication Date:
Language:
English

Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Chemistry
Committee Chair:
MILLER,STEPHEN ALBERT
Committee Co-Chair:
GRENNING,ALEXANDER JAMES
Committee Members:
SMITH,BEN W

Subjects

Subjects / Keywords:
khalid

Notes

General Note:
Both the performance and properties of ethylene/propylene copolymer-rubber EPM depend on the monomer distribution along the polymer chain. EPM was synthesized using different metallocene systems: (A) Oct-Cp catalyst, (B) Ewen catalyst, (C) Cp2ZrCl2 catalyst, and (D) Brintzinger catalyst (Figure 1.3). As a result, the EPM made from the metallocene catalyst (A) having Oct ligand has tendency to form long sequences of a-olefin vs. ethylene. This was seen by the relative amount between the comonomer as rerp >1. Moreover, the copolymer shows a dramatic increase of rp compared to re (reactivity ratio of ethylene and propylene, respectively). It has been noticed that the nature of the Oct ligand has influence on the copolymerization selectivity to incorporate more a-olefin than ethylene, the overall activity, and on the stereochemistry. Moreover, this particular copolymer almost bears no EEE sequences (ethylene triad sequences), which might lead to better thermal properties as it shows tendency for the Tg to be as high as -13 C. The sequence distributions of EPM copolymers was analyzed by 13C NMR as described by Randall. The polymerizations were conducted at 20 C in a liquid propylene with a constant overpressure of ethylene, or condensed ethylene.

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UFRGP
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All applicable rights reserved by the source institution and holding location.
Embargo Date:
5/31/2018

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SINGLE SITE CATALYST FOR NOVEL ETHYLENE/ PROPYLENE POLYOLEFIN S By KHALID MOHAMMED ALQAHTANI A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2016

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2016 Khalid Mohammed Alqahtani

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To my father, my mother, my wife, and my son

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4 ACKNOWLEDGMENTS I am grateful to many people for assistance, advice, and encouragement It was Prof Abdul Aziz Al Suhybany and Prof. Abdul Aziz Al Wassil who have first inspired me to purs ue a higher education; therefore I am thankful for their support and communication along with my graduate experience. I would like to thank Prof Miller who gives me a chance to join his group and for his support and guidance Also, I would like to thank my committee members Prof Gre nning and Prof Smith for their support s and encouragements I would like to thank all of Miller unit who have shared time and knowledge with me, more precisely Ha Nguyen for being a productive mentor and being there for discussion and ideas Also I would like to thank my employer SABIC for funding my higher education. Also, I would lik e to thank Dr. Abdul Aziz Al Humydi and D r. Khalid AlB ahily for their support and encouragement and all of my coll eagues at SABIC I am entirely grateful to my parents, my wife and my sibling who have supported and encouraged me.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 6 LIST OF FIGURES .......................................................................................................... 7 LIST OF ABBREVIATIONS ............................................................................................. 8 CHAPTER 1 MOTIVATION AND TARGETS ............................................................................... 10 1.1 Introduction ....................................................................................................... 10 1.2 Catalyst Design ................................................................................................. 14 1.2.1 Catalyst A ................................................................................................ 14 1.2.2 Catalyst B ................................................................................................ 15 1.3 Polymerization Results, Character ization, and Discussion ............................... 16 1.3.1 Results .................................................................................................... 16 1.3.2 Discussion and Characterization ............................................................. 16 2 EXPERIMENTAL PROCEDURES .......................................................................... 26 2.1 General Considerations .................................................................................... 26 2.2 Polymer Characterization: ................................................................................. 26 2.3 Synthesis of Catalysts ....................................................................................... 26 2.3.1 Preparation of Catalyst (A) ...................................................................... 26 2.3.1.1 Cyclopentadiene (1) ....................................................................... 26 2.3.1.2 6,6diphenylfulvene (2) ................................................................... 27 2.3.1.3 2,5dichloro2,5 dimethylhexane (3) ............................................... 27 2.3.1.4 O ctamethyloctahydrodibenzofluorene (4) ...................................... 27 2.3.1.5 Ph2C(C5H4)(C29H36)H2 (5) .............................................................. 28 2.3.1.6 Ph2C(C5H4)(C29H36)ZrCl2 (A) .......................................................... 28 2.3.2 Prepration of Catalyst (B) ........................................................................ 29 2.3.2.1 Ph2C(C5H4)(C13H8)H2 (6) ................................................................ 29 2.3.2.2 Ph2C(C5H4)(C13H8)ZrCl2 (B) ........................................................... 29 2.4 Copolymerization Procedure ............................................................................. 30 3 CONCLUSION ........................................................................................................ 31 LIST OF REFERENCES ............................................................................................... 32 BIOGRAPHICAL SKETCH ............................................................................................ 33

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6 LIST OF TABLES Table page 1 1 Reactivity ratios for ethylene/propylene copolymer 5 .......................................... 13 1 2 Polypropylene polymerization results ................................................................. 16 1 3 Ethylenepropylene copolymerization results with continuous ethylene flow at 20 C .................................................................................................................. 18 1 4 Ethylenepropylene copolymerization results with c ondensed ethylene at 20 C ....................................................................................................................... 18 1 5 EP copolymerization with Oct Cp (A) with continuous ethylene flow at 20 C .... 18 1 6 Monomer distributions and reactivity ratios9 ....................................................... 21 1 7 Monomer distributions and reactivity ratios for Oct Cp (A) ................................. 22 1 8 Monomer distributions and reactivity ratios for Ewen (B) .................................... 22 1 9 Monomer distributions and reactivity ratios for Oct Cp (A) ................................. 23 1 10 Monomer distributions and reactivity ratios for Ewen (B) .................................... 23 1 11 Monomer distributions and reactivity ratios for Oct Cp (A) ................................. 24

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7 LIST OF FIGURES Figure page 1 1 Selections of polyethylene microstructures ........................................................ 12 1 2 Major tacticity of polypropylene microstructures ................................................. 12 1 3 Selective structures of m etallocene catalysts ..................................................... 13 1 4 Synthesis of Oct Cp metallocene catalyst (A) ..................................................... 14 1 5 Synthesis of Ewen catalyst (B) ........................................................................... 15 1 6 Ethylenepropylene copolymer (EPM) ................................................................ 16 1 7 13C NMR of EP copolymer synthesized using Catalyst A ................................... 20 1 8 13C NMR of EP copolymer synthesized using Catalyst B ................................... 20 1 9 Peak assignment for ethylenepropylene copolymer (EPM)7,8 ............................ 21 1 10 Dyad distribution of ethylenepropylene copolymer; synthesized using a continuous ethylene ............................................................................................ 24 1 11 Dyad distribution of ethylenepropylene copolymer; synthesized using a continued flow of ethylene .................................................................................. 25

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8 LIST OF ABBREVIATIONS C Celsius Cat. Cp DSC EPM Equiv. g HDPE LDPE LLDPE MAO mL mol. NMR PE PP re rp Tg Tm Xe Xp Catalyst Cyclopentadiene Differential Scanning Calometry Ethylene/propylene rubber Equivalent Grams High density polyethylene Low density polyethylene Linear low density polyethylene Methylaluminoxane Milliliter Moles Nuclear magnetic resonance Polyethylene Polypropylene Reactivity ratio of ethylene monomer Reac tivity ratio of propylene monomer G lass transition temperature M elting temperature Mole fraction of ethylene Mole fraction of propylene Hapticity

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9 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science SINGLE SITE CATALYST FOR NOVEL ETHYLENE/ PROPYLENE POLYOLEFINS By Khalid Mohammed Alqahtani May 2016 Chair: Stephen A. Miller Major: Chemistry Both t he performance and properties of ethylene/propylene copolymer rubber EPM depend on the monomer distribution along the polymer chain. EPM was synthesized using different metallocene systems: ( A ) Oct Cp catalyst ( B ) Ew en catalyst ( C) Cp2ZrCl2 catalyst and ( D ) Brintzinger catalyst (Figure 1. 3 ). As a result, the EPM made from the me tallocene catalyst (A) having Oct ligand has tendency to form long sequences of olefin vs. ethylene. This was seen by the relative amount between the comonomer as rerp >1. Moreover, t he copolymer shows a dramat ic increase of rp compared to re (reactivity ratio of ethylene and propylene, respectively) It has been noticed that t he nature of the Oct ligand has influence on the copolymerization selectivity to incorporate more olefin than ethylene, the overall activity and on the stereochemistry Moreover, this particular copolymer almost bears no EEE sequences (ethylene triad sequences), which might l ead to better thermal properties as it shows tendency for the Tg to be as high as 13 C. The sequence distributions of EP M copolymers was analyzed by 13C NMR as described by Randall. The polymerizations were conducted at 20 C in a liquid propylene with a constant overpressure of ethylene, or condensed ethylene

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10 CHAPTER 1 MOTIVATION AND T A RGETS 1.1 Introduction Po lymer was found to make us live in a modern world. They are easy to make and easy to process, which h as contributed heavily to the facile development and use of polymer s. E xample of polymer goods include: rubber, milk bottles, shopping bags, dispensing bottles, piping, wire and cable insulation, food packages, disposable dippers, etc.1 A major type of pol ymer is polyolefin material, exemplified by polyethylene, polypropylene, and ethylene/ olefin copoly mer. About 60% of the worlds thermoplastic materials are homopolymers or copolymers containing ethylene and /or propylene.2 Polyolefin materials are various polymers using the same monomer with diffe rent type of heterogeneous catalysts activated by aluminum alkyls, or homogeneous catalysts activated by MAO or via radical chemistry However, the largest scale chemical processes are by heterogeneous catalyst s, which produces roughly 99% of the worlds polyethylene and polypropylene.3 Polyethylene can have different micro structure s due to density variation ( Figure 1 1 ). The branching has a large effect on the crystallinity of the polymer.3 Polyethylene including l inear low density polyethylene olefin ; l ow dens ity polyethylene (LDPE) is commercialized using free radical process at high temperature and pressures, and high density polyethylene (HDPE) is typically formed by Ziegler catalyst or supported chromium oxide catalyst.4 Also polypropylene architectures depend heavily on the relative configuration of the methyl groups along the polymer chain to produce isotactic polypropylene, syndiotactic polypropylene, or atactic polypropylene ( Figure 1 2 ) .4 These polymer s h ave different performance and properties from eac h

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11 other, which leads to a v a riety of applications. Therefore, LLDPE is used for plastic bags. O n the other hand, HDPE is used for milk bottles. A combination of the ethylene monomer and the propylene monomer is called co polymer, which are resistant to heat oxidation, ozone, weather and electrical resistor for having a saturated backbone.4 The performance and properties of the copolymer depend on the content distribution of ethylene and propylene in t he polymer chain. As a result, e thylenepropylene copolymer (EP M ) exhibit s lower crystallinity and higher imp act strength than isotactic polypropylene with a small amount of ethylene. In contrast, amorphous rubbery materials are produced with larger amount of ethylene than propylene.5 Therefore, the synthesis of the EP M copolymer would be controlled vi a reactivity ratio (rethylene, rpropylene) of the monomer s content. Interestingly, the relative amount of rerp is an indicator of the type of the copolymer. As a result, rerp = 1 indicates a random copolymer, rerp < 1 indicates an alternati ng copolymer, and rerp > 1 indicates the tendency to form long sequences of at least one of the comonomer.5 However, as it noted in the following reference,5 the reactivity ratio re and rp for most heterogeneous and homogen e ous catalysts have the tendency to form longer ethylene sequences ( T able 1 1 ).5 However, our catalyst containing the Oct ligand ( Oct = O ctamethyloctahydrodibenzofluorenyl) was used to synthesize copolymer of ethylene and olefin except propylene, is found to be more reactive to incorpo olefins than it does for ethylene.1 Keep in mind that ethylene and propylene has a tremendous impact in business field. Herein, w e explore our metallocene system catalyst ( A ) (Figure 1 3 ) to see if it will also be more selective toward propy lene than it does toward ethylene. Copolymer with more propylene incorporation than ethylene would result in a

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12 different microstructure which could form a novel polyolefin with better properties and b roaden applications. Figure 11. S elections of polyet hylene microstructure s Figure 12. Major tacticity of polypropylene microstructures

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13 Table 11 Reactivity ratio s for e thylene/propylene copolymer 5 Catalyst T, C r e r p r e r p ref

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14 1.2 Catalyst Design 1.2.1 Catalyst A The syntheses of these compounds are known, and has been accomplished by Miller et al.6 Figure 1 4 Sy nthesis of Oct Cp metallocene catalyst (A)

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15 1.2.2 Catalyst B The syntheses of these compounds are known, and have been accomplished by Ewen et al.11 F igure 15 Synthesis of Ewen catalyst (B)

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16 1.3 Polymeriza tion Results, Characterization, and Dis cussion 1.3.1 Results Homopolymerization was run first to demonstrate the fact that Oct Cp catalyst system is more reactive and stereoselctive than Ewen catalyst is. (Table12). Table 12. Polypropylene polymerization results Ethylenepropylene copolymerization was carried out at 20C (water b ath) in 20 mL of toluene, liquid propylene, and liquid ethylene/ or constant overpressure of ethylene. All copolymerizations were employed MAO as a co catalyst; for overall pressure, temperature, and sti rring speed limit, see Table 1 2 and T able 1 3 for copolymerization results. Figure 16 Ethylenepropylene copolymer ( EPM) 1.3.2 Discussion and Characterization M et allocene catalyst s show an interest to control the selectivity of incorporation of the comonomer due to their well defined kinetic behavior.2 R ecently, our group has shown that Oct ligand has influenced the catalyst to be more olefin t han entry Cat. (mg) MAO (equiv) T p (oC) C 3 H 6 (mL ) time (min) Yield (g) Reactivity (K g/mol.hr) 1 A (1.0) 2000 20 30 10 1.00 3300 2 B (1.0) 2000 20 30 1 0 1.09 1550

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17 it is for ethylene due to the steric demands and the electron donation of the tertiary alkyl groups of Oct ligand.1 The electron richness of the Oct ligand allow the ring slip to 1 therefore further metallocene bending creates more room for the approaching monomer to incorporate More interestingly, A /M AO also behaves similarly with ethylene propylene copolymerization, where propylene as a commoner is found to be faster toward the electron deficient metal center of the catalyst than it does ethylene. The first order Markov model is given by four equations as follow s: Where re and rp can b e simplified to re = k22/k21 and rp = k11/k12. M P indicates the active center with last propylene and M E indicates the active center with the last ethylene. Our point view is having a more electron rich comonomer would facilitate the insertion with catalyst ( A ) which is in this case the propylene comonomer. The Oct Cp catalyst influences on the reactivity ratio and the overall reactivity comp ared to E wen catalyst (B) that bears fluorenyl group. Table 1 3 shows that despite the copolymerizations were run with identical conditions, Oct Cp (A) produced significant higher activity ratio of propylene than the Ewen catalyst (B); also this observation was correlated with the results of entry 1 and 2 (Table 1 3 ) where the former has greater rp than t he later.

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18 Table 13 Ethylenepropylene copolymerization results with continuous ethylene flow at 20 C Table 14 Ethylenepropylene copolymerization results with condensed ethylene at 20 C Table 15 EP copolymerization with Oct Cp (A) with continuous ethylene flow at 20 C The results were analyzed by the 13C NMR spectra obtained; (Figure 1 7 ) and ( Figure 1 8 ). The Oct C p catalyst show s less integration of EEE sequences than the Ewen catalyst ( B ) Also, i t was noticed that Table 14 shows no dramatic increase change on the Tg and Tm of the produced polymer, which is an advantage for elastomeric material to have lower Tg. However, we are lacking the tools to control the composition and the entry Cat. (mg) MAO (equiv) X e / X p ( feed mol%) Time (min) T g (C) T m (C) r e r p r e r p 1 A (1.0) 2000 0.22 1 7 110 1.00 1.90 1.90 2 B (1.0) 2000 0.21 2 11 120 1.09 1.23 1.34 3 A (0.5) 1000 0.21 2 22 116 0.5 1 1.13 0.57 4 B (0.5) 1000 0.21 8 15 118 entry Cat. (mg) MAO (equiv) X e / X p (feed mol %) Time ( min) T g (C) T m (C) r e r p r e r p 1 A (0.5) 1000 0.26 1 43 104 1.6 0.7 5 1.19 2 B (0.5) 1000 0.26 10 41 n.o. 1.68 0.16 0.27 3 A (0.25) 1000 0.26 7 37 n.o. entry Cat. (mg) MAO (equiv) X e / X p (feed mole %) Time (min) T g (C) T m (C) r e r p r e r p 1 1.0 2 000 0.2 2 1 7 1 10 1. 00 1 90 1.19 2 0.5 1000 0.21 2 22 116 0.50 1.13 0.57 3 0.25 1000 0.21 7 37 n.o.

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19 conversion percentage of propylene comonomer, which might be the reason behind that The reported activity from ( T able 1 1) assumed the conversion is 10% from the propylene. As it has mentioned earlier, the Oct Cp catalyst is more active than Ewen catalyst ; therefore we assumed that the conversion with catalyst (A) is higher than 10% with such a highly active catalyst This clear l y can be seen from the reaction time through the data mentioned earlier leading to the sam e yield of the produced polymer Thus different amount s of Oct C p ( A ) were loa ded in to the copolymerization (Table 1 5 ) ; the catalyst has more control of the re activity ratio with lower loading which is correlated to what was mentioned earlier about the conversion of the propylene comonomer T he sequence distribution of the copolymer produced by A / MAO reveal ed a tend ency to increase PP dyad and diminish the EEE triad sequence (Figure 1 10) and (Figure 1 11) The copolymer composition was investigated by 13C NMR as has been accomplished by Carman and coworkers and Randall .7,8 The carbon positions w ere gi ven by S, T, and P refer respectively to the secondary (methylene), tertiary (methine) and primary (methyl) carbons, and used Greek letters to assign the distance from that carbon to methine away from the methine (Figure 1 9 ).

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20 Moreover, Kakugo and coworkers ;9 accomplished a way to calculate the mole percent of monomers in EP copolymers and reactivity ratios of monomers (Table 1 4). However in our case Xe/Xp is the mole feed fraction ratio of ethylene and propylene in the liquid phase. Figure 17 13C NMR of EP copolymer synthesized using Catalyst A Figure 18. 13C NMR of EP copolymer synthesized using Catalyst B

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21 Table 16 Monomer distributions and reactivity ratios9 Dyad & Triad distributions: Mole % of monomer in copolymer: Dyad: Triad: S T S S S S

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22 Table 17 Monomer distributions and reactivity ratios for Oct Cp (A) Table 18 Monomer distributions and reactivity ratios for Ewen (B) Dyad & Triad distributions: Mole % of monomer in copolymer: Dyad: PP = 0. 2 1 EP = 0. 65 EE = 0.14 Triad: PPP = 0.1 7 PPE = 0. 11 EPE = 0. 13 PEP = 0.1 7 EEP = 0. 38 EEE = 0.04 Dyad: E = 0. 14 + ( 0. 65 ) = 0. 465 P = 0. 2 1 + ( 0. 65 ) = 0. 535 Triad: E = 0.0 4 + 0. 38 + 0.1 7 = 0. 59 P = 0.1 7 + 0. 11 + 0. 13 = 0. 41 Ethylene & propylene reactivity ratio: rerp = 0. 14 [ 0. 21/( 0. 65 /2)2] = 0.2 7 re = ( 0.3 0 )/{[1 0.3 0 ]*[ 0.26]} = 1. 68 rp = ( 0.3 9 )*[ 0.26]/[1 0.3 9 ] = 0.16 Dyad & Triad distributions: Mole % of monomer in copolymer: Dyad: PP = 0. 55 EP = 0.38 EE = 0.08 Triad: PPP = 0. 48 PPE = 0.0 8 EPE = 0.0 9 PEP = 0. 10 EEP = 0. 22 EEE = 0.02 Dyad: E = 0.0 8 + ( 0. 38 ) = 0. 27 P = 0. 55 + ( 0. 38 ) = 0. 74 Triad: E = 0.02 + 0.22 + 0.10 = 0.34 P = 0.48 + 0.08 + 0.09 = 0.65 Ethylene & propylene reactivity ratio: rerp = 0.0 8 [ 0. 55/( 0. 38 / 2)2] = 1.19 re = ( 0. 30 )/{[1 0. 30 ]*[ 0.26]} = 1.6 rp = ( 0.7 4 )*[ 0.26]/[1 0.7 4 ] = 0.7 5

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23 Table 19 Monomer distributions and reactivity ratios for Oct Cp ( A ) Dyad & Triad distributions: Mole % of monomer in copolymer: Dyad: PP = 0.80 EP = 0.18 EE = 0.02 Triad: PPP = 0.72 PPE = 0.08 EPE = 0.04 PEP = 0.07 EEP = 0.09 EEE = 0.00 Dyad: E = 0.02 + ( 0.18 ) = 0.11 P = 0.80 + ( 0.18 ) = 0.89 Triad: E = 0.00 + 0.09 + 0.07 = 0.16 P = 0.72 + 0.08 + 0.04 = 0.84 Ethylene & propylene reactivity ratio: rerp = 0.02 [ 0.80/( 0.18 /2)2] = 1.9 0 re = ( 0.18 )/{[1 0.18 ]*[ 0.22]} = 1.00 rp = ( 0.89 )*[ 0.22]/[ 1 0.89 ] = 1.90 Table 110. Monomer distributions and reactivity ratios for Ewen (B) Dyad & Triad distributions: Mole % of monomer in copolymer: Dyad: PP = 0.71 EP = 0.26 EE = 0.03 Triad: PPP = 0.64 PPE = 0.08 EPE = 0.05 PEP = 0.10 EEP = 0.13 EEE = 0.00 Dyad: E = 0.03 + ( 0.26 ) = 0.16 P = 0.71 + ( 0.26 ) = 0.84 Triad: E = 0.00 + 0.13 + 0.10 = 0.23 P = 0.64 + 0.08 + 0.05 = 0.77 Ethylene & propylene reactivity ratio: rerp = 0.03 [ 0.71/( 0.26 /2)2] = 1.3 4 re = ( 0.19 )/{[1 0.19 ]*[ 0.22]} = 1.09 rp = ( 0.84 )*[ 0.22]/[1 0.84 ] = 1.23

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24 Table 11 1 Monomer distributions and reactivity ratios for Oct Cp (A ) Dyad & Triad distributions: Mole % of monomer in copolymer: Dyad: PP = 0.71 EP = 0.28 EE = 0.02 Triad: PPP = 0.63 PPE = 0.12 EPE = 0.04 PEP = 0.09 EEP = 0.13 EEE = 0.00 Dyad: E = 0.02 + ( 0.28 ) = 0.16 P = 0.71 + ( 0.28 ) = 0.85 Triad: E = 0.00 + 0.13 + 0.09 = 0.22 P = 0.63 + 0.12 + 0.04 = 0.79 Ethylene & propylene reactivity ratio: rerp = 0.02 [ 0.71/( 0.28 /2)2] = 0.57 re = ( 0.1 3 )/{[1 0.1 3 ]*[ 0.22]} = 0.51 rp = ( 0.84 )*[ 0.22]/[1 0.84 ] = 1.13 Figure 110. Dyad distribution of ethylenepropylene copolymer; synthesized using a continuous ethylene 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 PP % EP % EE % E % P % Ewen Cat. Oct-Cp Cat.

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25 Figure 111. Dyad distribution of ethylenepropylene copolymer; synthesized using a continued flow of ethylene 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 PP % EP % EE % E % P % Ewen Cat. Oct-Cp Cat.

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26 CHAPTER 2 EXPERIMENTAL PROCEDURES 2.1 General C onsiderations Most of the reaction procedures have been carried out under an atmosphere of argon or nitrogen using standard glove box, and Schlenk line techniques. The following were purchased from Aldrich and used as received: nbutyllithium (1.6 M in hexanes); zirconium tetrachloride (99.5%); aluminum chloride (99.99%); 2,5dimethyl 2,5 hexanediol (99%); and benzophenone (99%). The following were purchased from A cros and used as received; fluorene (98%); d i cyclopent a di ene (95%); and n itromet hane (96%) Benzened6 was dried over calcium hydride and isolated by vacuum transfer. 2.2 Polymer Characterization: P olymer glass transition temperatures and melting temperatures were obtained by the Different ial Scanning Calometry (TA DSC Q1000). S amples we re scanned from 80C to 200C at 10C/min. The reactivity ra tios of ethylene and propylene were calculated based on the 13C NMR spectra obtained by NMR 125 MHz at 124 C in tetrachloroethaned 2 A 90 pulse and a delay time of 3 s, acquisition time of 4 s and a minimum of 13 00 scans were used 2. 3 Synthesis of Catalysts The syntheses of A and B were accomplished similar to the literature procedure.3 2. 3 .1 Preparation of C atalyst ( A ) 2. 3 .1.1 Cyclopentadiene (1) A 180 mL of dicyclopentadiene was ch arged in a 250 ml vessel connected to a distillation apparatus After it was heated up to 160 C using oil bath, the internal temperature reach at 40 C to allow the retro Diels Alder reaction to occur. At the end,

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27 114 mL of cyclopentadiene is col lected in a 250 mL vessel and stirred in an ice bath and used immediately after being distilled. 2. 3 .1.2 6,6 diphenylfulvene (2) Sodium methoxide ( 2 1.00 g, 380 .0 mmol), ethanol (570 mL), and benzophenone (142.50 g, 782.0 mmol) were poured into a 1 L vessel Cyclopentadiene (114.0 mL, 677 mmol) was poured in cold, which gives a red solution. After stirring for 7 days, the orange precipitate was collected by filtration and rinsed with 50 mL ethanol. The solid was refluxed in 200 mL methanol for 2 hour. Upon c ooling the solid was collected, rinsed with 75 mL methanol, and dried in vacuo, to provide the product as an orange powder: 147.28 g (81.7%). 2. 3 .1.3 2,5 dichloro2,5 dimethylhexane (3) A 1 liter argon purged vessel was charged with 2,5dimethyl 2,5 hexane diol (53.77 g 0 .368 mol) and concentrated aqueous hydrochloric acid (269 mL, 1 0 8 mol HCl) was poured in. The white slurry was shaken and stirred for 19 hours. The white solid was collected by filtration lightly vacuumed and rinsed with 630 mL water. The solid was dissolved in diethyl ether, the water layer was removed, and the organic layer s was dried over MgSO4. The solvent was removed; precipitate was collected by the filtrate and washed with 50 mL of ethanol. The white crystalline solid was dried in vacuum to provide the product: 59.78 g (88 .7%) 2. 3 .1.4 O ctamethyloctahydrodibenzofluorene (4) A 2 liter argon purged vessel was charged with fluorene (26.32 g, 158.37 mmol) and 2,5dichloro2,5 dimethylhexane (58.5.00 g, 319.5 mmol). The solids were disso lved in 438 mL nitromethane and the vessel was equipped with an addition funnel which was charged with AlCl3 (28.12 g, 210 mmol) dissolved in 50 mL nitromethane.

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28 The solution was added over 10 minutes and the purple reaction was stirred for 48 hours before it was slowly poured into 500 mL of ice water. The precipitate was collected by filtration and refluxed in 500 mL ethanol for 2 hours. Upon cooling, the solid was collected by filtration and this was refluxed in 300 mL hexanes for 2 hours. After cooling, the solid was collected by filtration and dried in vacuo, giving the product as a white powder: 40.1g (65.5%) 2. 3 .1.5 Ph2C(C5H4)(C29H36)H2 (5) A 500 mL flask was charged with octamethyloctahydrodibenzofluorene (12.00 g, 31.04 mmol), equipped with a 180 ne edle valve, evacuated and charged with diethyl ether (120 mL) by vacuum transfer. At 0C, n butyllithium (21.0 mL, 33.6 mmol, 1.6 M in hexanes) w as syringed in over 3 minutes, giving much yellow precipitate. After 21 hours, the solvent was removed and 6,6diphenylfulvene (7.148 g, 31.04 mmol) was added. Diethyl ether (150 mL) was condensed in and the reaction stirred at room temperature for five days before 60 mL aqueous NH4Cl were added slowly at 0C. The organic layer was isolated and the aqueous layer was extracted with diethyl ether (4 x 100 mL). The combined organic layers were dried over MgSO4, filtered and rotavapped to provide the crude product in quantitative yield 89.4% (17.12 g) 2. 3 .1.6 Ph2C(C5H4)(C29H36)ZrCl2 (A) A 250 mL flask equipped with a swivel f rit was charged with ( 5 ) (3.00 g, 4 9 mmol), then d iethyl ether (35 mL) was condensed in at 78C, and nBuLi (6.1 mL, 9 73 mmol) was added before the cold bath was removed. The reaction was warmed up and stirred for 45 hours, solvent was removed and ZrCl4 (1.134 g, 4 9 mmol ) was added. D iethyl ether (35 mL) was condensed in at 78C and the cold bath was removed. After

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29 47 hours, the swivel f rit flipped upside down. The volume was reduced to 20 mL, and kept stirring overnight. Then, the pink material was collected and dried in vacuo: 0.6 g (20.0%). 2. 3 .2 Prepration of C atalyst (B) 2. 3 .2.1 Ph2C(C5H4)(C13H8)H2 (6) A 500 mL flask was charged with fluorene (14.43 g, 86.8 mmol), equipped with a 180 needle valve, evacuated, and 180 mL of diethyl ether were transferred in. nbutyllithium (55.0 mL, 87.1 mmol, 1.6 M in hexanes) was syringed in over ten minutes at 0C. After 19 hours, all solvent was removed and 6,6diphenylfulvene (20.00 g, 86 .7 mmol) was added and 100 mL diethyl ether was condensed in. After stirring for six days, the vessel was cooled to 0C and 60 mL water were very slowly added, followed by 30 mL aqueous NH4Cl solution. The slurry was suction filtered and the crude product was dissolved in Chloroform and dried over MgSO4 This was filtered hot through a ce lite layer and the slurry was rotovapped before crystal solid was collected and dried (28.78 g, 83.6%) 2. 3 .2.2 Ph2C(C5H4)(C13H8)ZrCl2 (B) A 250 mL flask equipped with a swivel f rit was charged with ( 6 ) (3.00 g, 7 56 mmol) and d iethyl ether (35 mL) was condensed in at 78C and nBuLi ( 7.3 mL, 15.2 mmol) was added before the cold bath was remov ed. The reaction was warmed up and stirred for 48 hours, solvent was removed and ZrCl4 (1. 77 g, 7 6 mmol) was added. Petroleum ether (35 mL) was condensed in at 78C and the cold bath was removed. After 47 hours, The volume was reduced to 20 mL, and kept stirring overnight. Then, the orange material was collected and dried in vacuo: 0. 4 g ( 13 %)

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30 2. 4 Copolymerization Procedure CAUTION: All polymerizations need to be done behind the blast shield during the polymerizati on. All polymerization reaction preparation were carried out in nitrogen atmosphere (glove box). Methylaluminoxane (MAO) was purchased in toluene solution from Sigm a Aldrich and was used as a powder after removal of all volatiles. Toluene was collected from M B ra u n purification system and dried according to standard p rocedures and it was f urther purified over sodium; finally degased using the Schlenk line Ultra high pure propylene from Matheson Gases (99.99 %) and Ethylene from AirGas (UHP grade) were used following drying through a Matheson 6410 drying system equipped with an OXYSORB column. All p olymerizations were carried out in a fume hood using a 3 oz Lab Crest glass high pressure reaction vessel and stirred by a magnetic stirrer bar. The vessel was filled with MAO and t oluene in the glove box before propylene was condensed over several minutes at 20 C. The vessel was then kept equilibrated at 20 C over 10 minutes. In case of copolymerization, ethylene then was condensed at 5 C using an ice bath and NaCl. After that, the vessel was warmed up for 10 minutes to 20 C in a water bath before the injection of the catalyst in a toluene solution via a 2 m L Hamilton gastight syringe. After the desired time, polymerization reactions were vented and quenched with a small volume of methanol/concentrated HCl (10:1), and kept stirring overnight. The polymer was collected by filtration. Finally, the residual amou nts of toluene and methanol were removed by vacuum to obtain a dry polymer

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31 CHAPTER 3 CONCLUSION In conclusion, a series of ethy lenepropylene copolymers was synthesized using different types of catalysts. It was found that the Oct Cp catalyst system with MAO has influenced the reactivity ratio of propylene vs. ethylene. Moreover, the Oct Cp catalyst system is capable o f producing elastomeric material of EP copolymer These results demonstrated the influence of Oct H ligand in metallocene catal ysts, which enhance the ring slip to be more facile than F luorene ligand; therefore the dominant factor is electronic rather than steric. As a result the more electron rich olefins would polymerize much faster than the less electron rich ethylene T he distribution of comonomer s in the produced copolymer was analyzed using 13C NMR. The sequence distributions of the copolymer are correlated with the larger 13C NMR intensity peaks Finally, the impact of the Oct Cp ligand can be on stereochemistry, reactivity, and selectivity olefin.

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32 LIST OF REFERENCES 1. Jianfag C .; Abboud K.A .; Miller S A. Dalton Trans 2013 42 9139 2. Fan W .; Leclerc,M. K.; Waymouth R. M. J. Am. Chem. Soc. 2001 123, 9555 956 3 3. Hartwig, J. F.; Organotransition Metal Chemistry: From Bonding to Catalysis ; University Science Books, Inc.: Brothers, E ., 2010, p 1050 1 060 4. https://en.wikipedia.org/wiki/Ethylene_propylene_rubber 5. Kravchenko, R.; Waymouth, R. M. Macromolecules 1998 31, 1 6 6. Miller, S. A.; Bercaw, J. E. Organometallics. 2004, 23 1777 1789. 7. Harrington R. A.; Wilkes C. E.; Carman C.J. Macromolecules 1976 10, 536 544. 8. Randall J.C. Macromolecules 1978, 11, 33 36. 9. Kakugo M.; Naito, Y.; Mizunuma, K.; Miyatake, T., Macromolecules 1982, 15, 1150 1152. 10. http://science.taskermilward.org.uk/mod1/KS4Chemistry/AQA/Module2/10_2_7.h tm 11. Razavi, A.; Atwood, J. L. J. Organomet. Chem. 1993, 459 117 123 12. Kashiwa, N.; Mizuno, A. ; Minami, S. Polym. Bull. 1984, 12 105. 13. Doi, Y.; Ohnishi, R.; Soga, K. Makromol. Chem., Rapid Commun. 1983, 4 169. 14. Natta, G.; Mazzanti, G.; Valvassori, A.; Sartori, G.; Bar bagallo, A. J. Polym. Sci. 1961, 51 429454. 15. Chien, J. C. W.; He, D. J. Poly m. Sci., Part A: Polym. Chem 1991, 29, 1585 1593. 16. Ewen, J. A. In Catalytic Polymerization of Olefins ; Kei, T., Soga, K., Eds.; Kodansha: Tokyo, 1986; p 271. 17. Drogemuller, H.; Heiland, K.; Kaminsky, W. In Transition Metals and Organometallics as Catalysts for Olefin Polym erization; Kaminsky, W., Sinn, H., Eds.; Springer Verlag: Berlin, 1988; p 303. 18. Zambelli, A.; Grassi, A.; Galimberti, M.; Mazzocchi, R.; Piemontesi, F. Makromol. Chem., Rapid Commun. 1991 12 523.

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33 BIOGRAPHICAL SKETCH Khalid Alqahtani was born in 1989 in Riyadh, Saudi Arabia. After high school he studied chemistry at the King Saud University where he obtained his bachelor s degree in ch emistry in June 2011. After graduation he work ed for SABIC ( Saudi Arabia Basic Industries Corporation). Then, h e got nominated for a m aster s program at the University of Florida in 2013. In Fall 201 4 Khalid joined Miller research group in the Organic Division of the Chemistry Department at the University of Florida. Under the guidance supervision by Prof. Stephen Miller, his research focuses o n the s ynthesis of polyolefin polymers. Khalid obtained his Master of Science degree from UF in May 201 6