Effects of n-Propanol Co-feeding in Isobutanol Synthesis from Syngas over K-CuMgCe Catalyst

The influence of n-propanol co-feeding in isobutanol synthesis from syngas was investigated over K-CuMgCe catalyst in a batch reactor. After the addition of n-propanol, the selectivity of isobutanol increased significantly. Moreover, it was different from the traditional fixed bed after adding alcohol, which was negative or had no significant impact on CO conversion. The CO conversion was increased significantly after the addition of n-propanol under the system conditions. It might be due to the back-mixing in the slurry bed, which increased the residence time of intermediate species on the catalyst surface. The consumption of C1 species from syngas through aldol condensation led to a shift in methanol equilibrium and a significant increase in CO conversion. As the ratio of n-propanol to CO increased, the reaction path changed from the aldol condensation of C1 species with n-propanol to the self-coupling of n-propanol. CO conversion reached 63.5 % and isobutanol selectivity reached the maximum of 28.2 % within a tolerable range of byproducts for n n-propanol/n CO=0.5. Excess of n-propanol would reduce isobutanol yield and was not conducive to CO conversion.