Preparation of carbon-based Ni–Ag bimetallic composite catalyst and its catalytic performance in transfer hydrogenation of fatty acid methyl esters

In this study, a carbon-based Ni–Ag bimetallic composite catalyst (Ni–Ag/AC) was prepared by the method of impregnation and chemical reduction with activated carbon (AC) as support, and was employed in the catalytic transfer hydrogenation (CTH) reaction of fatty acid methyl esters (FAMEs). The results of characterization indicated that Ni and Ag were successfully loaded onto the activated carbon. The CTH experiment of FAMEs was conducted using sodium borohydride (NaBH₄) as the hydrogen donor and water (H₂O) as the solvent. The optimal reaction conditions for the hydrogenation were obtained as follows: catalyst dosage 8 wt%, water quantity 60 g, reaction temperature 80 °C, NaBH₄ amount 1.135 g and reaction time 1.5 h. With the mentioned optimal reaction conditions, the conversion ratio of methyl linoleate was 86.45 %, and the iodine value dropped from the original 146.7 to 75.2. The rate constant (k₁) for the reaction from methyl linoleate (C18:2) to methyl oleate (C18:1) was about 0.01178 min¹, and the rate constant (k₂) for the reaction from C18:1 to methyl stearate (C18:0) was about 0.001978 min⁻¹. This study not only prepared a novel Ni–Ag/AC bimetallic composite catalyst, but also advances the development of the CTH reaction of FAMEs.