Kinetics, thermochemistry and mechanism of hydrogenolysis of aliphatic aldehydes on Ni–SiO2

Abstract

An investigation of the kinetics of the hydrogenolysis reaction of aliphatic aldehydes on Ni–SiO2 by stopped-flow chromatography is described and the rate plots fitted to theoretical equations which reveal that the reaction proceeds in two kinetically discernible stages, one apparently by a Langmuir–Hinshelwood mechanism and the other by a Rideal–Eley mechanism. These conclusions are supported by the dependences of the rates on the hydrogen pressure. Thermochemical measurements using a microcalorimetric device, have enabled the determination of the thermochemistry of a reaction leading to a surface species. A discussion of the prevailing mechanism is presented.