Synthesis and properties of novel aluminophosphate molecular sieves produced with ethylenediamine

Abstract

AIPO 4-12, CHNUAP-3, and CHNUAP-4 have been synthesized hydrothermally in the system of ethylenediamine-Al203-P20s-H20 at 150°C, using ethylenediamine as an organic templating agent. CHNUAP-3 and CHNUAP-4 are a new type of aluminophosphate molecular sieve. The influence of the initial pH value of the reaction mixture and the amount of the ethylenediamine used on the crystalline phases of the product was investigated. The crystalline phases of the products obtained are rather sensitive to the changes of the pH value and the amount of templating agent used in the starting reaction mixtures. The chemical analysis of the synthesized samples showed that their essential framework structures have a chemical composition, expressed in terms of molar ratios of oxides, of Al 1O 3:P 2O 5 = 1: ∼ 1. The physical and chemical properties of the obtained products were studied by chemical analysis. X-ray diffraction, scanning electron microscopy, infrared spectra, differential thermal analysis, and adsorption capacity determination. The catalytic property of the samples was investigated using the esterification of propionic acid with n-butanol as a model reaction. The experimental results indicate that CHNAUP-3, CHNAUP-4, and AIPO 4-12 have excellent adsorption properties and thermal stability and also higher catalytic activity for the esterification of propionic acid with n-butanol.