Thermodynamic properties and relative stability of polybrominated phenoxathiins by density functional theory

International Journal of Physical Sciences

C. Wang¹ 

关键词: Polybrominated phenoxathiins;    the number and position of Br atom substitution (NPBS);    thermodynamic property;    relative stability;    molar heat capacity at constant pressure (Cp;    m).;   

DOI  :  

学科分类：物理（综合）

来源: Academic Journals

【 摘 要 】

The thermodynamic properties of 135 polybrominated phenoxathiins (PBPTs) in the ideal gas state at 298.15 K and 1.013×105Pa have been calculated at the B3LYP/6-31G* level using Gaussian 03 program. The isodesmic reactions were designed to calculate standard enthalpy of formation (ΔfHө) and standard free energy of formation (ΔfGө) of PBPTs congeners. The relations of these thermodynamic parameters with the number and position of Br atom substitution (NPBS) were discussed, and it was found that there exist good correlations between thermodynamic parameters (entropy (Sө),ΔfHөandΔfGө) andNPBS. According to the relative magnitude of theirΔfGө, the order of relative stability of PBPT congeners was theoretically proposed. Moreover, using a statistical thermodynamics calculation program based on Gaussian output files, the values of molar heat capacity at constant pressure (Cp,m) from 200 to 1800 K for PBPT congeners were calculated, and the temperature dependence relation of them was obtained using the least-squares method.

【 授权许可】

CC BY