PALLADIUM CATALYST, PREPARATION METHOD THEREOF AND METHOD FOR PRODUCING SUCCINIC ACID Russian patent published in 2016 - IPC B01J23/44 B01J37/03 B01J21/04 B01J21/06 B01J21/08 C07C51/14 

FIELD: chemistry.

SUBSTANCE: invention relates to production of palladium catalysts, which can be used for hydrogenating organic electrolytes with unsaturated C-C bonds in molecules, in particular, for selective hydrogenation of maleic acid into succinic acid in aqueous medium. Catalyst is palladium nanoparticles with size of 1.2-5 nm, applied amount of 0.1-2.5 wt% per powder supports of various chemical nature (Al₂O₃, SiO₂, TiO₂, ZrO₂, Sibunit), having relatively low specific surface area of 2-455 m²/g, which minimises effect of diffusion of reagents, caused by existence of adsorbed solvate layers and double electric layer on surface of support, on rate of catalytic process. Required dispersed state of palladium nanoparticles is achieved by that hydrolytic precipitation of palladium on a support from solutions of H₂PdCl₄ is carried out at pH 9-9.5 directly in presence of support with further liquid-phase reduction of catalyst, which enables to achieve higher dispersion of applied metal due to complete hydrolysis of complexes of palladium chloride and reducing ageing time of formed hydro complexes in solution as a result of their fast adsorption on support.

EFFECT: technical result is high activity and selectivity of obtained catalysts for hydrogenation of maleic acid into succinic acid in aqueous medium in mild conditions.

5 cl, 2 dwg, 1 tbl, 15 ex