多溴代二苯胺热力学性质的密度泛函理论研究  

Density Functional Theory Study on the Thermodynamic Properties of Polybrominated Diphenylamines

作　　者：王辰[1] 方哲宇[1] 王遵尧[2] 王甫洋[3] 

机构地区：[1]北京大学物理学院介观物理国家重点实验室,北京100871 [2]南京大学环境学院污染控制与资源化研究国家重点实验室,南京210093 [3]江苏工业学院环境与安全工程学院,常州213164

出　　处：《化学学报》2009年第20期2319-2328,共10页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20977046);重点基金(No.20737001)资助项目

摘　　要：在B3LYP/6-31G*水平上对209个多溴代二苯胺(PBDPA)系列化合物进行了全优化和振动分析计算,得到各分子在298.15K,101.3kPa标准状态下的热力学参数.设计等键反应,计算了PBDPA系列化合物的标准生成热(ΔfHΘ)和标准生成自由能(ΔfGΘ).研究了热力学参数SΘ与溴原子的取代位置及取代数目(NPBS)之间的关系,结果表明:PBDPA系列化合物的SΘ,ΔfHΘ和ΔfGΘ与NPBS之间有很强的相关性(R2≥0.984).根据异构体标准生成自由能的相对大小,从理论上求得异构体的相对稳定性.以Gaussian03程序的输出文件为基础,采用统计热力学程序计算了PBDPA化合物在200K至1000K的摩尔恒压热容(Cp,m),并用最小二乘法求得Cp,m与温度之间的相关方程,发现Cp,m与T,T-1和T-2之间有着很好的相关性(R2=1.000).Fully optimized calculation and frequency analysis of 209 polybrominated diphenylamine （PBDPA） compounds were carried out by using a density functional theory （DFT） method at the B3LYP/6-31 G^＊ level and their thermodynamic parameters in the ideal gas state at 298.15 K and 101.3 kPa were obtained. The isodesmic reactions were designed to calculate standard enthalpy of formation （△fH^-） and standard free energy of formation （AfGe） of PBDPA congeners. The relationships of these thermodynamic parameters with the number and the position of Br atom substitution （NPBS） were established, finding that there exists high correlation of entropy （S^-）, standard enthalpy of formation （△fH^-）, standard free energy of formation （△fG^-） with NPBS （R^2≥0.984）. The stability of PBDPA congeners was theoretically proposed based on the relative magnitude of their △fG^-. Based on Gaussian 03 output files, the values of Cp,m in 200- 1000 K were calculated by using statistical thermodynamics calculation program and relative equation between Cp,m and temperature was obtained by the least square method, finding that Cp,m has a very good relationship with T, T^-1 and T^-2 （R^2= 1.000）.

关 键 词：多溴代二苯胺 密度泛函理论(DFT) 溴原子取代位置方法 热力学性质 相对稳定性 

分 类 号：O625.631[理学—有机化学]