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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (06): 617-626. 上一篇    下一篇

研究论文

多氟代、多氯代和多溴代二苯并对二噁英化合物的一些性质的比较研究

侯海锋1,2，陈斌媛2，张学胜2，王遵尧*,1   

  1. (1污染控制与资源化研究国家重点实验室 南京大学环境学院 南京 210093)
    (2常州大学环境与安全工程学院 常州 213164)
  • 投稿日期:2010-08-26 修回日期:2010-10-12 发布日期:2010-11-23
  • 通讯作者: 王遵尧 E-mail:wangzun315cn@163.com
  • 基金资助:

    持久性有机污染物的典型环境过程及构效关系研究

Comparative Studies on Some Properties of Polyfluorinated, Polychlorinated and Polybrominated Dibenzo-p-dioxins

Hou Haifeng1,2 Chen Binyuan2 Zhang Xuesheng2 Wang Zunyao*,1   

  1. (1 State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093)
    (2 Department of Environmental and Safety Engineering, Changzhou University, Changzhou 213164)
  • Received:2010-08-26 Revised:2010-10-12 Published:2010-11-23
  • Contact: WANG Zun-Yao E-mail:wangzun315cn@163.com

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被引次数

16

采用密度泛函理论(DFT)方法, 在B3LYP/6-311G**和B3LYP/6-31G*两种水平上, 对76种多氟代二苯并对二噁英系列化合物(PFDDs)进行了几何构型的全优化, 并计算了各分子在298.15 K, 1.013×105 Pa的标准状态下的热力学参数. 基组从6-31G*增大到6-311G**没有显著改变标准生成热(ΔfH?)、标准生成自由能(ΔfG?)和标准熵(S?)数值. 根据B3LYP/6-311G**水平计算得到的ΔfG?的相对大小, 求得PFDDs同数目取代氟原子的各异构体的相对稳定性的顺序. 采用基团贡献法计算了多溴代二苯并对二噁英(PBDDs)、多氯代二苯并对二噁英(PCDDs)和PFDDs的辛醇-水分配系数(lg Kow). 并将PFDDs的ΔfH?, ΔfG?, S?和lg Kow的计算结果与PBDDs和PCDDs的相关数值进行了比较. 同时, 计算了PFDDs各组异构体化合物的生成反应相对速率常数, 采用统计热力学程序计算了这些化合物在200至1800 K的恒压摩尔热容(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.

关键词: 多氟代二苯并对二噁英, 密度泛函理论, 热力学性质, 辛醇-水分配系数, 恒压摩尔热容

The thermodynamic properties of 76 polyfluorinated dibenzo-p-dioxins (PFDDs) in the ideal gas state at 298.15 K and 1.013×105 Pa have been calculated at the B3LYP/6-311G** and B3LYP/6-31G* levels using Gaussian 03 program, and it was found that values of standard enthalpy of formation (ΔfH?), standard free energy of formation (ΔfG?) and standard entropy (S?) were broadly consistent under the two base groups. According to the relative magnitude of their ΔfG? at the B3LYP/6-311G** level, the relative stability order of PFDD congeners was theoretically proposed. Octanol-water partition coefficients (lg Kow) of polybrominated dibenzofurans (PBDDs), polychlorinated dibenzofurans (PCDDs) and PFDDs were calculated by group contributions. Comparison of the properties (including lg Kow, S?, ΔfH? and ΔfG?) between PFDDs and PCDDs, PBDDs was carried out. Moreover, the relative rate constants of formation reactions of PFDDs and the values of molar heat capacity at constant pressure (Cp,m) from 200 to 1800 K for PFDDs congeners were calculated using a statistical thermodynamics calculation program. The temperature dependence relation of Cp,m was obtained using the least-squares method. The result shows that there exists very good relationship between Cp,m and temperature (T, T－1 and T－2) for almost all PFDD congeners.

Key words: polyfluorinated dibenzo-p-dioxins, DFT method, thermodynamic property, octanol-water partition coefficient (lg Kow), molar heat capacity at constant pressure (Cp,m)