Efficient conversion of lactic acid to alanine over noble metal supported on Ni@C catalysts.

Alanine (Ala), regarded as the building block for protein synthesis, has been widely used in the field of food processing, pharmaceutical, and bio-based plastic industries. Containing plenty of oxygenic functional groups, biomass-derived chemicals are proper for Ala synthesis in an economic and green way amination. In this work, lactic acid (LA) derived from renewable biomass and waste glycerol (the major by-product of biodiesel industry) was used to produce Ala. Here, a series of magnetic catalysts M/Ni@C (M = Ru, Pt, Pd, Ir, and Rh) were synthesized by ethylene glycol reduction of metal M supported on encapsulated Ni@C. Compared with catalysts based on other M metals, Ru/Ni@C catalysts exhibited extraordinary efficiency with 91.4% selectivity for Ala synthesis from LA (63.7% yield of Ala and 69.7% conversion of LA). The results of experiments and catalyst characterization indicated that the doping of M metals could improve the dehydrogenation ability of catalysts, as well as the ability of NH adsorption, facilitating the reaction towards Ala. Overall, this study provides an efficient chemo-catalytic way for the production of Ala from biomass-derived substrates.