THE CONVERSION OF SYNTHESIS GAS TO HIGHER OXYGENATED FUEL ON Rh-BASED CATALYSTS: EFFECT OF CHEMICAL ADDITIVES

Abstract

ABSTRACT In light of environmental concerns and the global economy, higher oxygenated fuel, such as ethanol, is a viable and attractive alternative to conventional gasoline. Presently, the major process to produce ethanol, the fermentation of corn, is economically inefficient. A more direct route, the reaction of synthesis gas (CO/H2) to produce higher oxygenates (aldehydes and alcohols), appears to be a better method. Rhodium catalysts have been known to exhibit higher oxygenate activity and selectivity from synthesis gas. The mechanism involves CO dissociation followed by hydrogenation to form an adsorbed CHX species. The CHX intermediate can undergo either hydrogenation to form methane, chain propagation to form higher hydrocarbons, or CO insertion to form C2 oxygenates. Experiments were performed to study the effects on the synthesis of higher alcohols from syngas of S, P, Cu, and Ag as additives to Rhodium supported on a silica support (Rh/Si02). The additive S was found to suppress the CO dissociati...