Polymerization of Isobutylene by GaCl3 or FeCl3/Ether Complexes in Nonpolar Solvents

Autor:	Rudolf Faust, Keith J. Bartelson, Philip Dimitrov, Rajeev Kumar, Jack Emert
Rok vydání:	2012
Předmět:	Isobutylene Polymers and Plastics Organic Chemistry Chain transfer Ether Inorganic Chemistry chemistry.chemical_compound End-group Chain-growth polymerization Polymerization chemistry Polymer chemistry Materials Chemistry Diisopropyl ether Ionic polymerization
Zdroj:	Macromolecules. 45:8598-8603
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma3017585
Popis:	The carbocationic polymerization of isobutylene (IB), co-initiated by GaCl3 or FeCl3·dialkyl ether 1:1 complexes has been investigated in hexanes in the −20 to 10 °C temperature range. In contrast to AlCl3·diisopropyl ether (AlCl3·i-Pr2O) complexes,(1) GaCl3·i-Pr2O and FeCl3·i-Pr2O readily co-initiate polymerization with 2-chloro-2,4,4-trimethylpentane (TMPCl) or tert-butyl chloride (t-BuCl) in the presence or absence of proton trap. In the absence of proton trap, chain transfer to monomer readily proceeded, resulting in close to complete monomer conversion and up to 85% exo-olefinic end group content. Diisopropyl ether complexes gave the highest polymerization rates, while nonbranched alkyl ether complexes were completely inactive. A polymerization mechanism is proposed to involve ether-assisted proton elimination to yield PIB exo-olefin, and the abstracted proton can subsequently start a new polymer chain by protonation of IB. Alternatively PIB+ may be deactivated by ion collapse to yield PIBCl, which c...
Databáze:	OpenAIRE
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