MIXED ALCOHOL SYNTHESIS FROM CARBON-MONOXIDE AND DIHYDROGEN OVER POTASSIUM-PROMOTED MOLYBDENUM CARBIDE CATALYSTS

Unsupported molybdenum carbides, beta-Mo2C and alpha-MoC1-x, promoted by K2CO3 were studied as catalysts for carbon monoxide-hydrogen reactions at 573 K and 8.0 MPa. Unpromoted molybdenum carbides produce mainly hydrocarbons of C1-C12 under these conditions. Addition of K2CO3 as a promoter, however, greatly enhances the selectivity to alcohols composed of linear C1-C7. Compared with better known alkali-promoted MoS2 catalysts, carbide catalysts show higher selectivities of C2-C7 alcohols. The carbon number distributions of both hydrocarbon and alcohol are consistent with the Schulz-Flory equation. Unlike MoS2 catalysts, the addition of hydrogen sulfide in the feed over molybdenum carbide catalysts causes a gradual decrease in activity and selectivity for alcohols with reaction time.