电荷转移盐(C_3H_5N_2H)_3[PMo_(12)O_(40)]的合成与热分解及光致变色反应动力学

Synthesis,Thermal Decomposition and Photochromic Kinetics of A Charge-transfer Salt(C_3H_5N_2H)_3[PMo_(12)O_(40)]

用磷钼酸与咪唑合成了一种新的杂多酸-有机电荷转移盐(C3H5N2H)3[PMo12O40]。通过元素分析、红外光谱、固体漫反射光谱、电子自旋共振及热分析等测试技术对其进行了表征,用单扫描法(Achar法和Coats-Redfern法)对合成化合物的TG分析结果进行了非等温热分解动力学研究。推断结果表明,合成化合物的第1步热分解为球对称的三维扩散机理(n=2),其动力学方程为dα/dt=1.58×108[1-(1-α)1/3]-1(1-α)2/3exp(-40931.0/T),求得分解反应的表观活化能E=340.30kJ/mol,指前因子A=1.05×108s-1。标题化合物对紫外光具有光致变色性质,用固体漫反射光谱研究了其光致变色反应动力学。结果显示,其光致变色反应表现为一级或准一级动力学,速率常数k=9.80×10-5s-1。

A new heteropolyacid-organic charge transfer salt （ C3 H5 N2 H） 3 [ PM012 040 J was synthesized from phosphomolybdic acid and imidazole, and characterized by means of elemental analysis, infrared spectrum （IR）, diffuse reflectance spectrum（DRS）, electron spin resonance（ESR） and thermal analysis techniques （TG）. The decomposition mechanism and nonisothermal kinetic parameters of the salt were obtained from an analysis of the TG-DTG curves obtained by means of the single scanning methods （ the Achar method and Coats-Redfern method ）. For the first step of the thermal decomposition reaction, the possible reaction mechanism was suggested to be a three-dimensional diffusion. Its kinetic equation with parameters is daJdt = 1.58x10s[1 - （1 -a）1/3]-1（1 -a）2/3exp（ -40 93i.0/T） with E =340.30 kJ/mol and A =1.05 ×10^8 s^-1. The salt shows photochromism under ultraviolet light, and its photochromic reaction was studied with solid diffuse reflectance spectra and found to exhibit first-order or pseudo-first-order kinetics with a rate constant k =9. 80 × 10^-5 s-1