Hydrogenolysis of C—O bond over Re-modified Ir catalyst in alkane solvent

Authors:  Yoshinao Nakagawa, Kazuma Mori, Kaiyou Chen, Yasushi Amada, Masazumi Tamura, Keiichi Tomishige

Abstract:
Hydrogenolysis of alcohols was carried out using n-heptane solvent and Ir ReO_x/SiO₂ catalyst, which has been known to be active in water solvent. Hydrogenolysis of trans-1,2-cyclohexanediol proceeded more smoothly in n-heptane than in water. The maximum yield of cyclohexanol was 74%, and at longer reaction time cyclohexane was selectively formed (>80% yield). Stronger adsorption of substrate on catalyst surface in n-heptane than in water is one of factors in obtaining the good yields. Alkane solvent was also advantageous to water solvent in hydrogenolysis of mono-alcohols. The reaction route via acid-catalyzed dehydration and subsequent hydrogenation is enhanced in alkane solvent. On the other hand,the “direct” hydrogenolysis driven by the hydride-like species is suppressed in alkane solvent, leading lower activity in n-heptane for hydrogenolysis of tetrahydrofurfuryl alcohol or 1,2-hexanediol, which smoothly react over Ir ReO_x/SiO₂ catalyst in water.

Keywords:
Hydrogenolysis
Alcohol
Solvent effect
Iridium
Rhenium

Published in: Applied catalysis A: General   (Volume 468, Pages 1-474, 5 November 2013)

Publisher: Elsevier  

ISSN Information: 0926-860X

Hydrogenolysis of C—O bond over Re-modified Ir catalyst in alkane solvent

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