Synthesis of Alcohols by Hydrogenation of Carbon Monoxide

Abstract

Current shortages have created considerable interest in the production of alcohols. This paper reviews the catalytic syntheses of alcohols from carbon monoxide and hydrogen. These processes may be divided into two classes: the alcohol syntheses in which alcohols are usually the predominant products, and variations of the Fischer-Tropsch process with iron catalysts in which the product contains olefinic and paraffinic hydrocarbons, alcohols, acids, esters, aldehydes, and ketones. The alcohol syntheses include the methanol, the higher alcohol, and the iso syntheses. The methanol and higher alcohol syntheses employ mixed catalysts of active components such as copper and oxides of zinc, chromium, and manganese, with alkali oxides added as promoter for the higher alcohol synthesis. Thoria is the active component of iso catalysts. Higher alcohols from these processes have branched carbon chains. Under some conditions the iso synthesis produces sizable yields of hydrocarbons. For iron Fischer-Tropsch catalysts, alkali oxides seem to be the only important promoter; however, the nature of the iron phase--oxide, carbide, or nitride--is important. Processes producing sizable yields of alcohol include the fluidized, synol, and nitrided catalyst syntheses. Fischer-Tropsch alcohols are chiefly primary straight-chain alcohols. Available data indicate that the mechanism of chain growth in alcohol syntheses is differentmore » from that of the Fischer-Tropsch processes.« less