Self-coupling of secondary alcohols by Ni/CeO2 catalyst

Authors:   Katsuya Shimura, Kenichi Kon, S.M.A. Hakim Siddiki, Ken-ichi Shimizu

Abstract:
Supported nickel catalysts are studied for the liquid phase C=C self-coupling of aliphatic secondary alcohols under additive free conditions in N₂ atmosphere. Among various Ni catalysts, 1 or 3 wt% Ni/CeO₂ catalysts pre-reduced in H₂ shows highest yield (94%) of a dimer product (a higher ketone) for the selfcoupling of 1-octanol at 130 ^◦C, and the catalyst is reused. The catalysts are also effective for self-coupling of various secondary alcohols, providing the first heterogeneous catalytic system for the self-coupling of secondary alcohols under mild conditions. Effects of support material and oxidation state of Ni on the activity are studied and it is found that both CeO₂ and metallic Ni are indispensable for the reaction. A possible reaction mechanism is proposed, in which ketones, formed by dehydrogenation of alcohol, undergone Aldol condensation to give ,-unsaturated ketone which is finally hydrogenated by in situ formed Ni H species.

Keywords:
C=C bond formation
Cerium oxide
Hydrogen transfer
Nickel

Published in: Applied catalysis A: General  (Volumes 462–463, Pages 1-310, 10 July 2013)

Publisher: Elsevier      

ISSN Information: 0926-860X

Self-coupling of secondary alcohols by Ni/CeO2 catalyst

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