Oxygenated octane enhancers: Syngas to isobutylene. Technical progress report No. 17, April 1, 1995--June 30, 1995

The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. The research will identify and optimize key catalyst and process characteristics. In addition, the commercial potential of the new process will be evaluated by an economic analysis. The effects of temperature, pressure and methanol/ethanol molar feed ratio on the performance of the 2% Pt on Zn/Mn/Zr Oxide catalyst has been evaluated in a series of pilot plant tests. Temperature has been varied from 325{degrees}C to 375{degrees}C, pressure from 30 psig to 300 psig and MeOH/EtOH ratio from 1 0/1 to 1 /1. Raising temperature increases alcohol conversion, but reduces selectivity and productivity to the desired branched C4 oxygenates. The higher pressure operation shifts the product ratio from isobutyraldehyde to isobutanol. Decreasing the feed ratio from 10/1 to 7/1 increases methanol conversion as well as selectivity to each of the iC4 oxygenates. However, further reduction of the feed ratio to 4/1 does not give additional improvement. Based on these findings a pilot plant test at optimized conditions is planned using the 2% Pt on Zn/Mn/Zr oxide catalyst. The effects of H{sub 2}, CO and CO{sub 2} co-feeds on the performance of the cztalyst have also been evaluated using the reference catalyst. Co-feeding H{sub 2} has very little effect, whereas CO has a deleterious effect. CO{sub 2} addition results in higher CO formation, but no substantial change in CO{sub 2} selectivity. Therefore, it appears that the use of a CO{sub 2} recycle would not be effective for reducing the formation of carbon oxide products. A copper-lined reactor has been constructed that gives acceptable blank activity at temperatures up to 450{degrees}C and used to evaluate the activity of the 2% Pt on Zn/Mn/Zr oxide catalyst for methanol-only conversion. At temperatures greater than 350{degrees}C, minimal branched C4 oxygenates are formed. Instead, the primary products are CO and CO{sub 2}