Influence of various parameters on synthesis of AlPO_4-5 molecular sieve using hexamethyleneimine template

摘要

AlPO_4-5 has been synthesized in aqueous and nonaqueous(ethylene glycol)media using hexamethyleneimine(HEM)as template.The ideal gel composition for the synthesis of AlPO_4-5 is Al_2O_3:P_2O_5:1.16HEM :45H_2O.The influence of compositional variations on the product and the effect of pH and temperature on crystallization kinetics have been investigated.Varying the composition of the gel produces other aluminophosphates such as AlPO_4-16,AlPO_4-22,AlPO_4-31 and SAPO-35.Crystallization is faster when HEM is used as the template than when triethylamine or cyclohexylamine is used.The crystallinity(X-ray)of the AlPO_4-5 samples synthesized from the nonaqueous medium are higher than those obtained from aqueous media.