Altervalent cation-doped MCM-41 supported palladium catalysts and their catalytic properties

Abstract

Metal cation-doped MCM-41 (M-MCM-41, M = Al, Ce, Co, V or Zr) supported Pd catalysts (Pd/M-MCM-41) were prepared by a solution-based reduction method. The catalysts were characterized by X-ray diffraction (XRD) analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and further evaluated by selective hydrogenation of para-chloronitrobenzene (p-CNB) in anhydrous ethanol. The metal cation-containing Pd catalysts can efficiently enhance the selectivity for para-chloroaniline (p-CAN). The highest selectivity of 96.5 % in the molar distribution for p-CNB to p-CAN was acquired over Pd (1.8 wt. %)/V-MCM-41 (Si/V = 30, molar ratio) catalyst, and the corresponding turnover frequency (TOF) was 1.24×10-2 mol p-CNB mol-1 Pd s-1. Water molecules adsorbed by the support have important effects on both the catalytic activity of the sample and the selectivity for p-CAN. A water molecule-mediated catalytic hydrogenation is discussed.

Keywords

• metal cation-doped MCM-41
• para-chloronitrobenzene
• hydrogenation
• para-chloroaniline.