Synthesis of Silylene-Bridged Thiophene-Fused Cyclopentadienyl ansa-Metallocene Complexes for High-Performance Supported Catalyst
- 주제(키워드) supported catalyst , metallocene catalyst , ethylene polymerization , silica , methylaluminoxane , slurry process
- 주제(DDC) 547
- 발행기관 아주대학교
- 지도교수 이분열
- 발행년도 2022
- 학위수여년월 2022. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000031473
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
A series of Me2Si-bridged ansa-zirconocene complexes coordinated with thiophene-fused cyclopentadienyl ligand and fluorenyl ligand [Me2Si(2-R1-3-R2-4,5-Me2C7S)(2,7-R32C13H6)]ZrMe2 (9, R1 = Me, R2 = H, R3 = H; 10, R1 = Me, R2 = Me, R3 = H; 11, R1 = H, R2 = H, R3 = H; 12, R1 = Me, R2 = H, R3 = tBu; 13, R1 = Me, R2 = H, R3 = Cl) were synthesized with an aim to prepare a supported catalyst adoptable in a commercial process. Fluorenyl anion is more basic than thiophene-fused cyclopentadienyl, and sequence of reaction order to Me2SiCl2 was crucial to achieve high yield; successive addition of fluorenyl-Li and thiophene-fused cyclopentadienyl-Li to Me2SiCl2 resulted in high yield (87%) while addition in the reverse sequence afforded the ligand precursor in low yield (27%). X-ray crystallography studies of 9 revealed that fluorenyl ligand adopts an 3-binding mode. Related Me2Si-bridged ansa-zirconocene complex 15 was also prepared replacing fluorenyl ligand in 9 with 2-methyl-4-(4-tert-butylphenyl)indenyl ligand, although it was obtained as a mixture of two diastereomers. Furthermore, ansa-metallocene complexes 20 and 23 containing tBuO(CH2)6- were prepared by replacing Me2Si-bridge in 12 and 15 with tBuO(CH2)6(Me)Si-bridge. Silica supported catalysts prepared with 12 showed two times higher productivity than the one prepared with the conventional (THI)ZrCl2 (26 vs. 12 kg-PE/g-(supported catalyst)) with polymers with comparable molecular weight (Mw, 330 vs. 300 kDa) but containing higher amount of 1-hexene content (1.3 and 1.0 mol%) being produced, although the bulk density of generated polymer particles was rather inferior (0.35 vs. 0.42 g/mL).
more목차
1. Introduction 1
2. Results and Discussion 2
2.1 Preparation of ansa-metallocene complexes 2
2.2 Preparation of the supported catalyst and ethylene/1-hexene copolymerization 12
3. Conclusions 14
4. Experimental Section 15
4.1 General remarks 15
4.2 Synthesis of ligands and complexes 15
4.3 Preparation of supported catalysts 19
4.4 Ethylene/1-hexene polymerization 19
4.5 X-ray crystallography 19
5. Reference 20
