Kinetics of the higher alcohol synthesis over a K-promoted CuO/ZnO/Al[sub 2]O[sub 3]

Journal Article · Thu Sep 01 00:00:00 EDT 1994 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00033a001· OSTI ID:6961107

Boz, I; Sahibzada, M; Metcalfe, I S ^[1]

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1. Imperial Coll. of Science, Technology, and Medicine, London (United Kingdom). Dept. of Chemical Engineering and Chemical Technology

Detailed kinetic experiments of higher alcohol synthesis over K-promoted CuO/ZnO/Al[sub 2]O[sub 3] catalysts have been performed using an internal recycle reactor operated at 4 MPa and between 548 and 578 K. It was found that a 0.5% K-promoted catalyst, a stoichiometric H[sub 2]/CO ratio (approximately 2), and a low (2%) CO[sub 2] concentration were favorable for isobutanol yield. In contrast, for the synthesis of methanol, a higher K loading, H[sub 2]/CO ratio, and CO[sub 2] concentration were found to be favorable. The results suggest that isobutanol synthesis requires a balanced level of oxidation (Cu/Cu[sup 1+]), as conformed by in situ X-ray photoelectron spectroscopy, while methanol synthesis requires a greater degree of oxidation (more Cu[sup 1+]). Contact time experiments showed the selectivity of aldehydes to pass through a maximum, suggesting the intermediacy of aldehydes in a classic aldol'' condensation mechanism. In extended time-on-stream experiments, initial deactivation was accounted for by a loss in BET surface area and a loss in Cu/Zn ratio. Greater deactivation at higher temperatures resulted in lower final activities; nevertheless steady-state isobutanol yields increased significantly at higher temperatures.

• OSTI ID: 6961107
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Vol. 33:9; ISSN 0888-5885
• Country of Publication: United States
• Language: English

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100200* - Synthetic Fuels- Production- (1990-)