Cleavage of double bond using metal‐loaded ZSM‐5 zeolite catalysts for renewable biochemical application

Abstract

This work aimed to investigate the use of mesoporous metal‐loaded ZSM‐5 zeolites for efficient cleavage of C═C double bonds for renewable biochemical applications. In the presence of a benign H2O2, these catalysts exhibited the high catalytic activities for oxidation of double bonds in styrene and fatty acids. Selective oxidation of styrene forming benzaldehyde was first studied using mesoporous Cr/ZSM‐5 zeolite as a model reaction to evaluate the catalytic activity in the cleavage of the double bond. Oxidation of double bonds in some typical fatty acids such as oleic, erucic, and linoleic acids was carried out subsequently following the model reaction. The mesoporous Cr/ZSM‐5 zeolite showed a high conversion yield of styrene (over 85 % after 6 h reaction at 70 °C) and high selectivity for benzaldehyde (over 74 %) as well as a high conversion yield of cleavage of double bond in fatty acids. To enhance the activity of the catalyst, tungsten transition metal was loaded on the Cr/ZSM‐5 particles. The mesoporous W‐Cr/ZSM‐5 zeolite was then applied as a catalyst for oxidative cleavage of several fatty acids for the generation of useful, low molecular weight chemicals from renewable natural resources. The results showed that the mesoporous W‐Cr/ZSM‐5 zeolite provided a higher conversion of fatty acids but lower selectivity in aldehyde type products than the mesoporous Cr/ZSM‐5 zeolite. The influences of reaction conditions such as reaction time and temperature on the efficiency of oxidation were also investigated.