Selective catalytic transfer hydrogenation of polyunsaturated fatty acid methyl esters using Pd/organobentonite as catalyst under microwave heating

Abstract

In this study, the catalytic transfer hydrogenation (CTH) of polyunsaturated fatty acid methyl esters (FAMEs) was carried out using ammonium formate as hydrogen donor and Pd/organobentonite (Pd/OB) as catalyst under the assistance of microwave. The effects of different technology parameters on the content of each FAME composition were investigated during the CTH reaction, and the optimal reaction conditions for the hydrogenation of FAMEs were determined. Under the optimal CTH conditions (40 g as the amount of ammonium formate, 60 g as the water amount, 8 wt.% as the catalyst dosage, 80 °C as the reaction temperature, 140 min as the reaction time and 350 rpm as the agitation speed), methyl linoleate (C18:2) was successfully hydrogenated into methyl oleate (C18:1) with high C18:2 conversion ratio (CRC182) of 78.56% and high C18:1 yield of 72.22%, and high selectivity for cis-C18:1 of 70.29%. Compared with conventional heating, microwave heating used in the CTH could enhance the CRC182 from 60.27% to 78.56% and reduce hydrogenation time. Moreover, the reaction of microwave-assisted CTH accorded with pseudo-first-order dynamic model through analyzing the obtained experimental data. In general, the effective hydrogenation of polyunsaturated FAMEs could be achieved under the microwave-assisted CTH reaction.