二水草酸锌脱水的热分解动力学研究

A Description of Thermal Decomposition Kinetics of Dehydration of Zinc Oxalate Dihydrate

提出一种多升温速率-等温法确定机理函数g(α)的新方法;并用迭代的等转化率法求出较为可靠的活化能Ea;在Ea和g(α)的基础上计算出指前因子A.用该法对二水草酸锌(ZnC2O4·2H2O)脱水反应的热分解动力学三因子进行了求算,得出Ea为87.22kJ·mol-1,A为4.2120×108～7.2328×108s-1;以及随机成核和随后生长型机理函数Am(Avrami-Erofeer),其积分形式g(α)=犤-ln(1-α)犦m-1和微分形式f(α)=m(1-α)·犤-ln(1-α)犦(1-m-1),调节因子m=1.85～2.00.

A new method of the multiple rates isotemperature is proposed to define the most possible mechanism g(α ) of thermal decomposition;the iterative isoconversional procedure has been employed to estimate apparent activation energy Ea;the pre exponential factor A is obtained on the basis of Ea and g(α ).By this new method,the thermal analysis kinetic triplet of dehydration of zinc oxalate dihydrate is determined,where apparent activation energy Ea is 87.22 kJ· mol- 1;pre exponential factor A is 4.2120× 108～ 7.2328× 108 s- 1 and the most probable mechanism belongs to random nucleation and growth Am(Avrami Erofeer equation) ,with integral form <IMG SRC='IMAGE/02180003.JPG' HEIGHT=15 WIDTH=151><IMG SRC='IMAGE/02180004.JPG' HEIGHT=15 WIDTH=228> and differential form ,accomodation factor m=1.85～ 2.00.