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ABE Condensation over Monometallic Catalysts: Catalyst Characterization and Kinetics

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2017-02-01
GOULAS, Konstantinos A.
Günbaş, Emrullah Görkem
DİETRİCH, Paul J.
SREEKUMAR, Sanil
GRİPPO, Adam
CHEN, Justin P.
GOKHALE, Amit A.
TOSTE, F. Dean
Herein, we present work on the catalyst development and the kinetics of acetone-butanol-ethanol (ABE) condensation. After examining multiple combinations of metal and basic catalysts reported in the literature, Cu supported on calcined hydrotalcites (HT) was found to be the optimal catalyst for the ABE condensation. This catalyst gave a six-fold increase in reaction rates over previously reported catalysts. Kinetic analysis of the reaction over CuHT and HT revealed that the rate-determining step is the C-H bond activation of alkoxides that are formed from alcohols on the Cu surface. This step is followed by the addition of the resulting aldehydes to an acetone enolate formed by deprotonation of the acetone over basic sites on the HT surface. The presence of alcohols reduces aldol condensation rates, as a result of the coverage of catalytic sites by alkoxides.