Ni-B amorphous alloy deposited on an aminopropyl and methyl co-functionalized SBA-15 as a highly active catalyst for chloronitrobenzene hydrogenation

Abstract

The synthesis and characterization of SBA-15 type mesoporous silica containing surfaces functionalized with aminopropyl and methyl groups (NH 2&CH 3-SBA-15) were reported. The Ni-B amorphous alloy deposited on such support showed higher activity and selectivity in liquid-phase hydrogenation of p-chloronitrobenzene ( p-CNB) to p-chloroaniline ( p-CAN) owing to the synergetic promotions from both the aminopropyl and methyl groups. The aminopropyl could greatly enhance the dispersion of Ni-B alloy particles via coordination with Ni 2+ ions, leading to high activity. While, the methyl could enhance the surface hydrophobicity which facilitated the desorption of the target product p-CAN and thus inhibited its further dechlorination. Besides, the strong hydrophobicity also enhanced the B-content in the Ni-B alloys, which favored the activation and hydrogenation of the NO 2-group in p-CNB molecule, leading to high selectivity. This work clearly reveals the importance of organization of different functional groups on the surface of heterogeneous catalysts.