物理化学学报 >> 2004, Vol. 20 >> Issue (01): 50-54.doi: 10.3866/PKU.WHXB20040111

研究论文 上一篇    下一篇

阿司匹林的热解机理及热动力学研究

徐芬;孙立贤;谭志诚;梁建国;周丹红;邸友莹;兰孝征;张涛   

  1. 中国科学院大连化学物理研究所,材料热化学实验室,大连 116023;湖南省药品检验所,长沙 410000; 辽宁师范大学化学系,大连 116029
  • 收稿日期:2003-06-13 修回日期:2003-09-15 发布日期:2004-01-15
  • 通讯作者: 孙立贤 E-mail:lxsun@dicp.ac.cn

Studies on Thermal Decomposition Mechanism and Kinetics of Aspirin

Xu Fen;Sun Li-Xian;Tan Zhi-Cheng;Liang Jian-Guo;Zhou Dan-Hong;Di You-Ying;Lan Xiao-Zheng;Zhang Tao   

  1. Material Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023; Hunan Institute of Drug Detection,Changsha 410000;  Department of Chemistry, Liaoning Normal University, Dalian 116029
  • Received:2003-06-13 Revised:2003-09-15 Published:2004-01-15
  • Contact: Sun Li-Xian E-mail:lxsun@dicp.ac.cn

摘要: 在用热重法研究了阿司匹林的热稳定性实验的基础上,通过量子化学方法(ab initio DFT)计算了阿司匹林分子的键级,据此计算结果提出了阿司匹林的热解机理,按此机理得到的理论计算值与实验结果一致;运用Freeman-Carroll、Kissinger和Ozawa三种方法分别计算了阿司匹林的热解动力学参数:活化能(E)、反应级数(n)和指前因子(A),其热解动力学方程为: dα/dt=4.74×1011[exp(-(100.34±5.18)×103/RT)](1-α)2.8±0.3;用差示扫描量热法测定的该物质的熔点、摩尔熔化焓和摩尔熔化熵分别为(409.19 ± 0.22) K、(29.17 ± 0.41) kJ•mol-1和(71.09±1.06) J•mol-1•K-1.

关键词: 阿司匹林, 量化计算, 热解机理和热动力学, 热重法, 差示扫描量热法

Abstract: The mechanism of thermal decomposition of aspirin was studied by both thermogravimetry and Mayer bond orders calculated by Cerius2 software. The parameters of thermal decomposition kinetics for aspirin, such as activation energy (E), reaction order (n) and frequency factor (A) were obtained by thermogravimetry. The kinetic equation of thermal decomposition of aspirin is expressed as: dα/dt=4.74×1011[exp-(100.34±5.18)×103/RT]](1-α)2.8±0.3 Melting point, molar enthalpy and entropy of fusion of aspirin were examined to be (409.19±0.22) K, (29.17±0.41) kJ•mol-1 and (71.09±1.06) J•mol-1•K-1, respectively, by means of DSC with a rising temperature program. The results obtained show that theoretical mass-loss derived from Mayer bond orders of aspirin is in very good agreement with that obtained from thermogravimetry experiment.

Key words: Aspirin, Quantum chemistry calculation, Mechanism and kinetics of thermal decomposition, Thermogravimetry, Differential scanning calorimetry(DSC)