VO(H_2PO_4)_2热分析研究

运用ＴＧ、ＤＴＡ，研究了ＶＯ（Ｈ２ＰＯ４）２在流动空气气氛中的热反应行为、非等温反应动力学和热效应。ＶＯ（Ｈ２ＰＯ４）２从６０９Ｋ开始失重，到６９５Ｋ失重完毕，失重率为１４．０１％，失重后的产物为ＶＯ（ＰＯ３）２。运用Ｓｈａｒｐ法、Ｃｏａｔｓ－Ｒｅｄｆｅｒｎ法和Ｄｏｙｌｅ－Ｚｓａｋｏ法对基础实验数据进行分析，推断出该热分解反应机理为成核和生长（ｎ＝１），动力学函数为Ａｖｒａｍｉ－Ｅｒｏｆｅｅｖ方程；非等温热分解反应动力学方程：ｄα／ｄＴ＝Ａ／βｅ－Ｅ／ＲＴ（１－α）；动力学补偿方程：ｌｎＡ＝０．１８１Ｅ－４．６８ｂ；热分解反应转变热为０．２９１ｋＪ·ｇ－１。

Study on Thermal Analysis of VO(H 2PO 4) 2

The thermal reaction of VO(H 2PO 4) 2,its kinetics and calorific effect were investigated under flowing air condition by TG,DTA techniques.The weight loss of VO(H 2PO 4) 2 is from 609K to 695K,amounting to 14.01%.The nonisothermal kinetic data were analyzed by means of Sharp,Coata Redfern and Doyle Zsako's method.The possible reaction fate was suggested by comparing kinetic parameters of different kinetic functions.The results show that the thermal reaction fate is a “Coring and Growth”(n=1) and the kinetic function is Avrami Erofeev equation.The kinetic equation can be expressed as dα/dT=A/βe -E/RT (1-α). The kinetic compensation effect equation: lnA=0.181E-4.68b. Heat content of the thermal decomposition reaction of VO(H 2PO 4) 2 is 0.291 kJ·g -1 .