槲皮素和芦丁的热分解动力学研究

Decomposition Kinetics of Quercetin and Rutin Flavonoids

采用热重法(TG)测定了槲皮素和芦丁的TG-DTG曲线.结果表明:槲皮素的DTG曲线有一个明显的失重峰,峰顶温度为349℃,失重率为33.32%.芦丁的DTG曲线有三个失重峰,在278℃的失重峰最为明显,失重率为29.71%.用TG-DTG法对两者在非等温条件下进行热分解动力学研究,把从TG-DTG曲线中取得的数据和30个不同的方程采用Achar微分法和Madhusudanan-Krishnan-Ninan(MKN)积分法对其进行非等温分解动力学研究,得到动力学参数(表观化学能E和频率因子A)和分解动力学机理及方程.得出结论:槲皮素和芦丁动力学方程均为dα/dt=A,exp(-E/RT3)/2(1-α4)/3[1/(1-α1)/3-1]-1,其分解机理符合三维扩散机理Three-dimensional,3D.二者的表观化学能分别为93.63和107.86 kJ.mol-1l,n A分别是25.80和39.57 s-1.

The thermal behaviors of quercetin and rutin and their decomposition kinetics have been investigated under nonisothermal conditions by means of thermogravimetry （TG）. The thermal characteristics have been determined using the TG- DTG curves. The top decomposition temperatures of the two compounds are 349℃ and 278℃. The mass losses of them are 33.32% and 29.71%, respectively. The non-isothermal kinetics of the samples was studied by use of non-isothermal TG and DTG curves. The non-isothermal kinetics data were analyzed by means of Achar differential method and Madhusudanan- Krishnan-Ninan （MKN） integral method. The possible reaction mechanisms have been investigated by comparing the kinetics parameters. The both of kinetic equations for the quercetin and rutin can be expressed as da/dt = Aexp （ -E/RT ）^3/2 （ 1- α ）^4/3[1/ （ 1-α ）1/3-1]^-1.The activation energy E of the two flavonoids are 93.63 and 107.86 kJ mol^-1 individually. Their lnA are 25.80 and 39.57 s^-1, respectively.