摘要
本文合成了四个钼钒砷三元杂多酸:Hx[AsVnMo12-nOy]ZH2O=1-4,简讯Vn。经元素分析,pH电位滴定,差热热重分析、红外等确定了结构组成。用程序升温还原(TPR)研究了它们分别与H2和CO反应的氧化催化性能,发现,随钒取代增多,活性降低。在微型反应器中,考查了V1和V3时叔丁醇生成甲基丙烯醛的催化作用,发现V1活性高于V3,选择性则是V3高于V1。即随钒取代增多,活性降低,选择性提高。
Four molybdovanadoarsenic acid, Hx [ AsVnMo12-nOy ]. ZH2O (n = 1-4), were prepared by extraction with ether from aqueous solutions. Their compositions were determined by elementery analysis, potentiometric titration in non-aqueous solution and static heating and evaluation of weight loss. IR spectrography, UV absorption spectrograhgy and x-ray powder diffraction revealed that all these compounds have keggin structure. The decomposition temperatures of these compounds were determined by thermogravimetric and differential thermal analysis. Their oxidixing catalytic activity was studied by temperature programmed reduction of these compounds with hydrogen and carbon monoxide. It was found that oxidizing catalytic activity decreases as the number of vanadium atoms in each molecule increases. Catalytic activity of V1 and V3 for choice oxidation of tert-butyl alcohol with microreactor was examined. V1showed more high activity than V3.