Metal particle size and swelling effect in the chiral hydrogenation of ethyl piruvate over Pt supported on resins

CARRARA NICOLAS R.; VERA CARLOS; MENDOW GUSTAVO; BADANO JUAN MANUEL; QUIROGA MÓNICA

Florence

Congreso; XIII European Congress on Catalysis EUROPACAT; 2017

European Commitee of Catalysis

The use of noble metal catalysts supported on an ionic exchange resins was studied for the enantioselective hydrogenation of ethyl pyruvate to ethyl lactate. High activity and moderate enantioselectivity levels were obtained. Pt was the best active metal phase, followed by Pd, Au and Rh. The reaction was found to be structure-sensitive and the importance of the metal particle size for the adsorption of the chiral modifier was proved. A novel method for sintering of the metal particles was used and a controlled migration of the metal particles to the surface layers was observed. There existed an optimal particle size that maximized the enantiomeric excess, corresponding to 24 h sintering. Two different chirality induction methods were tried: i) the addition of the modifier to the reaction media, ii) the modification of the catalyst in a swelling medium prior to the reaction. Lower activity but higher enantioselectivity levels were obtained with method (ii).