Homogene oder heterogene Katalyse? Simultane Verwendung von basischen und sauren Zeolithen in der flüssigen Phase bei der Umesterung und Veresterung |
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Authors: | Frank Roessner |
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Affiliation: | Carl v. Ossietzky Universität Oldenburg, Technische Chemie 2, Ammerländer Heerstraße 114, 26111 Oldenburg, Deutschland |
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Abstract: | Base catalyzed transesterification of triglycerides with methanol was studied in liquid phase on a K-LSX zeolite. The presence of free fatty acid results in its deactivation. Their esterification was catalyzed by an acidic H-Y zeolite. Surprisingly, in case of mixing of both catalysts, no catalytic activity was observed. Consequently, both reactions should proceed homogeneously because the formation of the intermediate methylat ion is suppressed. This could be explained in term of a fast ion exchange between the K+ ions of K-LSX and the H+ ions of Y-zeolite. On the other hand, the observed transport limitation indicates on a heterogeneously catalyzed reaction. Therefore, in case of even non-aqueous liquid phase reactions, a contribution of a homogeneous reaction path must be considered. |
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Keywords: | Katalysatorgift Saure und basische Zeolithe Simultane Um- und Veresterung Acidic and basic zeolites Catalyst poisoning Esterification Transesterification |
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