SCREENING OF ALKALI-PROMOTED VAPOR-PHASE-SYNTHESIZED MOLYBDENUM SULFIDE CATALYSTS FOR THE PRODUCTION OF ALCOHOLS FROM SYNTHESIS GAS

A series of molybdenum sulfide catalysts has been prepared using vapor -phase decomposition of molybdenum hexacarbonyl in an atmosphere of hy drogen sulfide. The effect of the decomposition conditions on the prop erties of the molybdenum sulfides formed has been studied over a tempe rature range of 300-900 degrees C. These materials, when promoted with alkali, have been found to have; a high activity for the production o f alcohols from synthesis gas. The effects of the catalyst preparation temperature (i.e., decomposition temperature) and reaction conditions (temperature, flow rate) have been studied, as well as the effect of the type and concentration of the alkali promoter. In all cases, the a lcohols formed are primarily straight-chain, terminal -OH compounds. T he variations in preparation procedure have only small effects on the conversion and the selectivity to higher alcohols. Increasing the reac tant flow rate increases the selectivity to methanol at the expense of the hydrocarbons and the higher-molecular-weight alcohols. Increasing the reaction temperature changes the selectivity toward higher alcoho ls but also changes the selectivity toward hydrocarbons. A maximum in selectivity to higher alcohols with the reaction temperature is observ ed for all catalysts tested.