Bifunctional Catalysts for the Production of Ethyl Acetate from Ethanol

• Main Authors: Su, Shyh Fang, 蘇世芳
• Other Authors: Chang Jen Ray
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/93926420930700875141

碩士 === 國立中正大學 === 化學工程研究所 === 86 === At the past research we found that Pd/SDB(Styrene divinyl benzene copolymer) can directly transfored ethanol (contained 7.52% H2O) to ethyl acetate(ethanol conversion 40%﹐ethyl acetate selectivity 54%﹐acetic acid selectivity 37%)by one step. But ,because of the interaction between metal and hydrophobic support are so week﹐palladium and the intermediate products,acetic acid, easily to become Pd(CH3COO)2,and induced metal extraction(metal extraction 50%).With improved metal extraction﹐we used Y-Zeolite as our support﹐using bifunctional catalysis to eliminate acetic acid selectivity. Otherwise﹐the interaction between metal and support is greatly improved by using Y-Zeolite support﹐and eliminate metal extraction(metal extraction <0.1%).From EXAFS data analysis of our fresh and used catalyst, we know, because the H2O adsorbed on the surface of catalysts and then it interacted with Pd clusters to form PdOH2, and then metal agglomeration which was induced by water poisoning, and then catalysts deactivated. So we add Amberlyst 35 in the Pd/SDB system, using the hydrophobic property to prevent metal agglomeration from water poisoning: and eliminate the contact time between acetic acid and catalyst. Therefor we can eliminate the metal extraction in the Pd/SDB system. In the research we found, the ratio between Amberlyst35 and Pd/SDB have greatly relation to ethanol conversion, ethyl acetate selectivity, acetic acid selectivity, and metal extraction. When the ratio between Amberlyst35 and Pd/SDB equal to 0.4/1, it''s the optimum mixer condition to operate.(ethanol conversion 46%,ethyl acetate selectivity 74%,acetic acid selectivity 17%,metal extraction<1%). But at the higher ratio between Amberlyst35 and Pd/SDB(4/1), there are no better performance(ethanol conversion 50%, ethyl acetate selectivity 77%,acetic acid selectivity 17% metal extraction 2%). At the other side, we used higher ratio of Si /Al catalyst, as hydrophobic support, to prevent metal agglomeration and eliminate metal extraction; and the result is matched our goal(ethanol conversion 31%,ethyl acetate selectivity 63%,acetic acid selectivity 25%,metal extraction<1%). But at higher temperature we found: ethanol will dehydrate to form ethylene , and then ethylene polymerized to become coke. Coke will occupied the active site, and then catalyst deactivated.