Novel solid basic catalysts by nitridation of zeolite beta at low temperature

Abstract

New basic solid catalysts are obtained by nitridation of zeolite beta at temperatures as low as 300 °C. These materials exhibit excellent catalytic activity in the Knoevenagel condensation of benzaldehyde with dicyanomethane (malononitrile). Nitridated samples of zeolite beta were prepared by treating the parent materials in an ammonia flow at temperatures between 300 °C and 800 °C for 24 h and 48 h, respectively. Samples of zeolite beta nitridated at 300 °C for 24 h or 48 h exhibited excellent catalytic activities which are higher than those observed for beta-type catalysts nitridated at higher temperatures and higher than activities reported earlier for ammonia treated aluminosilicates, AlPOs, SAPOs, and mesoporous silicon oxinitride materials. The nitridated beta zeolites were characterized by powder XRD, FTIR, nitrogen adsorption and elemental analysis techniques. It is suggested that the presence of silanol groups along with basic -NH2 functional groups is responsible for the exceptional activity of the catalysts treated at low temperature. © 2005 Elsevier Inc. All rights reserved.