Applied Catalysis A: General, Vol.468, 418-425, 2013
Hydrogenolysis of C-O bond over Re-modified Ir catalyst in alkane solvent
Hydrogenolysis of alcohols was carried out using n-heptane solvent and Ir-ReOx/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-ReOx/SiO2 catalyst in water. (C) 2013 Elsevier B.V. All rights reserved.