Preparation and characterization of Au-In/APTMS-SBA-15 catalysts for chemoselective hydrogenation of crotonaldehyde to crotyl alcohol

Mesoporous siliceous SBA-15 functionalized by γ-aminopropyltrimethoxysilane (APTMS) was used to immobilize Au and Au–In nanoparticles via the amino groups. The uniformly sized Au and Au–In spherical particles of around 2 nm were homogeneously dispersed on the mesopore walls of SBA-15. In liquid phase hydrogenation of crotonaldehyde to crotyl alcohol, on the optimal Au5.0In0.75/APTMS-SBA-15 catalyst, the initial selectivity amounts to 78%, and the maximum yield reaches 71%. The high selectivity originates from the suppression of the hydrogenation of the CO bond being lower than that of the CC bond after the incorporation of In. Furthermore, the catalyst can be conveniently recovered for reuse without losing its selectivity. In light of a series of spectroscopic studies, the superior catalytic performance of the Au5.0In0.75/APTMS-SBA-15 catalyst is tentatively attributed to the electron-donating effects of APTMS and In alloying with Au, favoring more the binding and hydrogenation of the CO bond in crotonaldehyde.

Au–In nanoparticles immobilized on γ-aminopropyltrimethoxysilane-functionalized mesoporous siliceous SBA-15 are highly selective and stable in liquid phase hydrogenation of crotonaldehyde to crotyl alcohol. The superior catalytic performance of the Au5.0In0.75/APTMS-SBA-15 catalyst is tentatively attributed to the electron-donating effects of APTMS and In alloying with Au, favoring more the binding and hydrogenation of the CO bond in crotonaldehyde.Figure optionsDownload as PowerPoint slide