Highly dispersed palladium nanoclusters incorporated in amino-functionalized silica spheres for the selective hydrogenation of succinic acid to γ-butyrolactone

Highly dispersed palladium nanoclusters incorporated on amino-functionalized silica sphere surfaces (Pd/SiO2-NH2) were fabricated by a simple one-pot synthesis utilizing 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS) as coordinating agent. Uniform palladium nanoclusters with an average size of 1.1 nm can be obtained during the co-condensation of tetraethyl orthosilicate and AAPTS owing to the strong interaction between palladium species and amino groups in AAPTS. The palladium particle size can be controlled by addition of AAPTS and plays a significant role in the catalytic performance. The Pd/SiO2-NH2 catalyst exhibits high catalytic activity for succinic acid hydrogenation with 100% conversion and 94% selectivity towards gamma-butyrolactone using 1,4-dioxane as solvent at 240 degrees C and 60 bar for 4 h. Moreover, the Pd/SiO2-NH2 catalyst is robust and readily reusable without loss of its catalytic activity. Copyright (C) 2015 John Wiley & Sons, Ltd.