ISSN:
0268-2605
Keywords:
Polystyrene
;
syndiotactic
;
syndioselective
;
MAO
;
cationic catalysts
;
trityl tetrakis(pentafluorophenyl)borate
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An equimolar mixture of Cp*Ti(CH3)3 (2) and Ph3C+[B(C6F5)4]- (1) forms a highly active and syndioselective catalyst for the polymerization of styrene, producing 96% syndiotactic polystyrene (PS) at an activity of 0.91 × 107 g PS (mol Ti)-1 (mol styrene)-1 h-1. Both activity and syndioselectivity can be increased using tri-isobutylaluminum (TIBA) to scavenge the system. ESR measurements indicate that the polymerization proceeds via titanium(IV) intermediates. Catalysts derived from 2/methylaluminoxane (MAO) as well as Cp*TiCl3/MAO also function as syndioselective styrene polymerization catalysts, but are less active than the ‘cationic’; system derived from 1 and 2.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aoc.590080413
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