【摘要】 首次采用差示扫描量热法(Differential scanning calorimetry,DSC)和热重法(Thermogravimetry,TG)在氮气气氛下对白藜芦醇和白藜芦醇苷进行非等温热分析,采用Van’t Hoff方程求得其纯度和熔点,并使用积分Coats-Redfern法、微分Achar法以及Malek法3种热分析动力学方法对热重实验数据进行分析,推断两种天然产物快速热分解阶段的最概然机理函数,并求得相应的动力学参数——表观活化能Ea和指前因子A。研究表明,白藜芦醇及其苷的纯度分别为99.76%和98.90%,熔点分别为257.09℃和198.79℃;白藜芦醇的热分解发生在220~468℃之间,失重率为46.69%;白藜芦醇苷在198~369℃之间发生分解,主要是糖苷键断裂引起的分解失重,失重率为37.47%;白藜芦醇的热分解为化学反应控制机制,符合反应级数方程,反应级数n=2;白藜芦醇苷的热分解为三维扩散控制机制,符合Z.-L.-T.方程;根据白藜芦醇及其苷的热分解动力学参数,推断二者在室温(25℃)下的贮存期分别为3年和4~5年,糖苷键的引入使白藜芦醇苷比白藜芦醇有更长久的贮存期。更多还原

【Abstract】 In this work,resveratrol and piceid were non-isothermally analyzed by differential scanning calorimetry( DSC) and thermogravimetric( TG) methods under the nitrogen atmosphere. The melting point and purity were calculated by Van’t Hoff equation while the kinetic parameters( including the most probable mechanism function,apparent activation energy Eaand pre-exponential factor A) were inferred by three thermal analysis kinetics methods( Coats- Redfern method,Achar method and Malek method). The results showed resveratrol and piceid( 99. 76% and 98. 90%) of high purity melted at 257. 09 ℃ and 198. 79 ℃,respectively. The thermal decomposition of resveratrol began at 220 ℃ and ended up at 468 ℃ with mass loss of 46. 69%. Piceid decomposed from 198 ℃ to369 ℃ with mass loss of 37. 47%,which could be explained by the cracking of glycosidic bond. The most probable thermal decomposition mechanisms of resveratrol and piceid were Chemical Reaction and three dimensional diffusion,respectively,corresponding with reaction order equation( the order of reaction n = 2) and Z.- L.- T. equation. According to kinetic parameters of thermolysis,the shelflives of resveratrol and piceid at room temperature( 25 ℃) were inferred as 3 years and 4- 5years,respectively.更多还原