Reaction pathways and catalyst requirements in the synthesis of isobutanol from CO and H{sub 2}
- Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering
The synthesis of isobutanol and methanol from CO/H{sub 2} on K-Cu-Mg-CeO{sub x} catalysts is inhibited by CO{sub 2}, one of the reaction products. Alcohol coupling reactions show that CO{sub 2} decreases the rates of both alcohol dehydrogenation and base-catalyzed chain growth condensation reactions. Basic site density and reactivity were determined using a {sup 12}CO{sub 2}/{sup 13}CO{sub 2} isotopic transient technique. Addition of K to Cu-Mg-CeO{sub x} increases both basic site density and strength, but influences weakly the rate of base-catalyzed alcohol coupling reactions. Cu enhances the rates of alcohol dehydrogenation, and Ce increases Cu dispersion and stabilizes high surface area MgO. The cross-coupling reactions of acetaldehyde and {sup 13}C-labeled methanol produce singly-labeled propionaldehyde, suggesting that it forms by the condensation of acetaldehyde and a reactive intermediate derived from methanol. Isobutyraldehyde, a precursor to isobutanol, forms via the condensation of propionaldehyde and reactive C{sub 1} species resulting from methanol. Temperature-programmed surface reaction studies of preadsorbed ethanol have shown that CO decreases the rate of base-catalyzed self-condensation reactions of ethanol to acetone, possibly due to the poisoning of basic and metal sites by the CO{sub 2} formed from CO by water-gas shift or Boudouard reactions.
- OSTI ID:
- 549578
- Report Number(s):
- CONF-960954--
- Country of Publication:
- United States
- Language:
- English
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