| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 88 === Abstract
The commercial production of ethyl acetate is mainly by two processes: the Tischenko reaction which produces ethyl acetate by direct conversion of ethanol via acetaldehyde using aluminum alkoxide catalyst; and the production of ethyl acetate by direct esterification of ethanol with acetic acid using a sulfuric acid catalyst. Since both process have wasted-catalyst-treatment problem and have to suffer high cost of raw material, it motivates us to develop a process for the conversion of water-containing ethanol to ethyl acetate. By Pd/SDB (styrene divinylbenzene copolymer) catalyst developed before, the process includes two stages operated in a fix-bed reactor. The first stage is the catalytic oxidation of ethanol to acetic with air over the Pd catalyst and the second stage is the esterification of acetic acid with ethanol over Amberlyst-15 catalysts. In this study, we found that Pd(II)-acetate formed from the reaction of the reaction immediate, acetic acid, with Pd clusters on the catalysts results in a leaching and aggregating of Pd clusters thereby decreasing the catalyst activity. To remedy the drawbacks of the catalysts, zeolite-supported bimetallic catalysts have been developed. By controlling the properties of supports including pore size, acidity, and polarity, the goals of high esterification selectivity, stability maintenance, and low impurity have been achieved. The experimental results indicated that catalyzed by Pd-X(Pt, Ag, Ni, Ru, Zn)/Zeolite catalysts, about 62.5% ethanol was converted and the selectivity to ethyl acetate selectivity was up to 93.3%. Moreover, since the catalysts can be regenerated under very mild conditions, they are regarded to be promising for industrial application.
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