Premium
Hydrogen activation in propene polymerization with MgCl 2 ‐supported Ziegler‐Natta catalysts: the effect of the external donor
Author(s) -
Chadwick John C.,
Miedema Arjen,
Sudmeijer Olof
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950114
Subject(s) - propene , catalysis , polymer chemistry , chemistry , chain transfer , polymerization , monomer , ziegler–natta catalyst , hydrogen , lewis acids and bases , base (topology) , photochemistry , polymer , radical polymerization , organic chemistry , mathematical analysis , mathematics
13 C NMR analysis of relatively low‐molecular‐weight polypropylenes prepared using the catalyst system MgCl 2 /TiCl 4 /phthalate ester‐AlEt 3 ‐external Lewis base has revealed the presence of up to around 20% butyl ( n ‐Bu) chain ends, indicative of regioirregular (2,1‐) monomer insertion followed by chain transfer with hydrogen. The effect of hydrogen on catalyst activity depends on the nature of the external donor, and the results indicate that at least part of the observed increase in catalyst activity in the presence of hydrogen can be ascribed to the regeneration of active species via chain transfer at dormant (2,1‐inserted) sites.