The role of some bases in the stereospecific polymerization of propylene with titanium catalysts supported on magnesium chloride

✍ Scribed by Pino, Piero ;Rotzinger, Bruno ;von Achenbach, Eduardo

• Publisher: Wiley (John Wiley & Sons)
• Year: 1985
• Weight: 707 KB
• Volume: 13
• Category: Article
• ISSN: 0025-116X
• DOI: 10.1002/macp.1985.020131985109

✦ Synopsis

The influence o f Lewis bases on the s t e r e o s p e c i f i c i t y and p r o d u c t i v i t y o f c a t a l y t i c systems o f the type MgCl /TiC14/A1Rj as w e l l as on m i c r o t a c t i c i t y and molecular weight o f t8e polymer f r a c t i o n s has been systematically investigated using propylene as monomer. The r e s u l t s are i n keeping w i t h the hypothesis t h a t beside non stereospecific centers two types o f stereospecific c a t a l y t i c cent e r s exist,in one o f which the Lewis base i s present. The centers can be c l a s s i f i e d according t o t h e i r Lewis acidity,the more a c i d i c centers y i e l d i n g polymers w i t h lower molecular weight and t a c t i c i t y . The s t r u c t u r e o f the Lewis bases i s o f paramount importance i n determining the s t e r e o s p e c i f i c i t y o f the c a t a l y t i c systems and can be used as a probe t o investigate the s t r u c t u r e o f the d i f f e r e n t c a t a l y t i c centers.