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Updated: May 4, 2026

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Spectral studies of a Cr(PNP)-MAO system for selective ethylene trimerization catalysis: searching for the active
Loi H Do1, Jay A Labinger, John E Bercaw
1Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125.
Abstract:
Variable temperature spectroscopic, kinetic, and chemical studies were performed on a soluble CrIIICl3(PNP) (PNP = bis(diarylphosphino)alkylamine) ethylene trimerization precatalyst to map out its methylaluminoxane (MAO) activation sequence. These studies indicate that treatment of CrIIICl3(PNP) with MAO leads to first replacement of chlorides with alkyl groups, followed by alkyl abstraction, and then reduction to lower-valent species. Reactivity studies demonstrate that the majority of the chromium species detected is not catalytically active.
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