INITIAL CARBON-CARBON BOND FORMATION DURING SYNTHESIS GAS CONVERSION TO HIGHER ALCOHOLS ON K-CU-MG5CEOX CATALYSTS

Isotopic tracer studies of alcohol synthesis pathways using (CO)-C-13/ H-2/(CH3OH)-C-12 mixtures have shown that ethanol is formed predominan tly by direct reactions of (CO)-C-13 on Cu0.5Mg5CeOx promoted with K a t short residence times, without significant involvement of the (CH3OH )-C-12 present in the feed. The observed decrease in C-13 content in e thanol with increasing residence time is caused by reverse aldol react ions of higher alcohols, which contain lower C-13 contents because of the significant involvement of (CH3OH)-C-12 in their formation, and by reactions of methyl formate with (CH3OH)-C-12-derived species. The ef fects of residence time on the C-13 distribution within reaction produ cts and on the rates of formation of ethanol, methyl formate, and meth yl acetate are consistent with the intermediate role of methyl formate and methyl acetate in ethanol formation.