A NOVEL METHOD FOR THE SYNTHESIS OF CANCRINITE TYPE ZEOLITES

摘要

A novel method for the synthesis of cancrinite type zeolites was developed by modificationrnof an X faujasite type zeolite (ZX). The ZX zeolite was impregnated with NaOH, Na_2CO_3,rnAl(NO_3)_3 and/or Mg(NO_3)_2 gels using three times the volume corresponding to the incipientrnwetness of the zeolite. Synthesis parameters such as crystallization time (16 h), temperaturern(80℃) and pressure (autogenous pressure) were highly reduced by this procedure comparedrnto previous synthesis methods. XRD, FTIR, TGA, SEM, BET surface area and chemicalrnanalysis confirmed the synthesis. A 100% conversion of the ZX to cancrinite was observedrnwith crystallinity higher than 80%. No other phases different to that of the cancrinite werernobserved. The basic character of the cancrinite was ascertained by means of its catalyticrnactivity in the Knoevenagel condensation reaction.