Carbon monoxide hydrogenation over silica-supported rhodium catalysts. The effect of the rhodium precursor

Abstract

The effect of changing the metal precursor on activity and selectivity in the medium pressure (1.01 MPa) hydrogenation of carbon monoxide has been investigated. Nine precursors were tested using silica as the support. Differences in specific activity were observed with turnover frequencies varying by two orders of magnitude. The specific activity was found to be related to the amount of surface hydrocarbonaceous residue retained per site; the higher the deposit: site ratio the higher the activity. Selectivity was also observed to vary, by up to a factor of five, when the metal precursor was changed. We suggest that the variations in available site geometries on the metal crystallites play a significant role in determining selectivities.