Gas-phase S-alkylation of benzenethiol with aliphatic alcohols, ethers, esters, alkyl halides and olefins over halide cluster catalysts of Groups 5 and 6 transition metals

Authors: Sayoko Nagashima, Kentaro Kudo, Hitomi Yamazaki, Satoshi Kamiguchi, Teiji Chihara

Abstract:
Benzenethiol was reacted with methanol under a hydrogen stream over [(Nb6Cl12)Cl2(H2O)4]·6H2O supported on silica gel. Catalytic activity of the cluster commenced above 250 ◦C, yielding methyl phenyl sulfide. The selectivity was 98% at 400 ◦C. Molybdenum, tantalum and tungsten halide clusters with the same octahedral metal framework also catalyzed the reaction. Primary alcohols with shorter alkyl chains were effective reagents for the S-alkylation. Aliphatic ethers, dialkyl carbonates, orthoesters and alkyl halides were effective reagents for the S-alkylation. When 1-hexene was applied to the reaction, spontaneous and catalytic S-alkylation proceeded simultaneously above 200 ◦C, yielding n-hexyl phenyl sulfide. When alkyl acetates were subjected to this reaction, the niobium cluster afforded S-phenyl thioacetate, and the other clusters afforded alkyl phenyl sulfides selectively. A Brønsted acid site attributable to a hydroxo ligand, which is formed on the cluster complex by thermal activation, is proposed as the active site of the catalysts.

Keywords:
S-Alkylation
Benzenethiol
Sulfide
Thioacetate
Halide cluster

Published in: Applied catalysis A: General  (Volume 450, Pages 1-274, 15 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Gas-phase S-alkylation of benzenethiol with aliphatic alcohols, ethers, esters, alkyl halides and olefins over halide cluster catalysts of Groups 5 and 6 transition metals

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