气相色谱法测定及预测有机磷阻燃剂的蒸气压

以p,p′-二氯二苯三氯乙烷(p,p′-DDT)为参考化合物,采用气相色谱法(GC)测定了14种有机磷阻燃剂(OPFRs)在不同温度(T)条件下的蒸气压(P_(GC))及其蒸发热。根据获得的蒸气压值,发现14种OPFRs的log P_(GC)随着温度的增加而减小。初步探讨了分子结构与log P_(GC)的相关性,结果发现卤代烷基磷酸酯的log P_(GC)低于烷基和芳基磷酸酯,且随着分子摩尔体积的增大,相应的log P_(GC)呈下降趋势。采用逐步回归的方法,建立了OPFRs的相对保留时间(RRT)与log P_(GC)之间的定量构效关系(QSPR)模型,模型的累计交叉有效判别系数Q2cum为0.946。模型对OPFRs的log P_(GC)预测值与实验值有良好的相关性(r=0.980),结果表明所建模型具有良好的稳健性和预测能力。利用建立的方法,通过测定的保留时间参数以及定量构效关系模型,可有效预测目前没有标准品的OPFRs的log P_(GC)值。

Determination and prediction for vapor pressures of organophosphate flame retardants by gas chromatography

Organophosphate flame retardants (OPFRs) are ubiquitous in the environment. To better understand and predict their environmental transport and fate, well-defined physicochemical properties are required. Vapor pressures (P) of 14 OPFRs were estimated as a function of temperature (T) by gas chromatography (GC), while 1,1,1-trichioro-2,2-bis (4-chlorophenyl) ethane (p,p'-DDT) was acted as a reference substance. Their log P_GC values and internal energies of phase transfer (△ _vapH) ranged from -6.17 to -1.25 and 74.1 kJ/mol to 122 kJ/mol, respectively. Substitution pattern and molar volume (V_M) were found to be capable of influencing log P_GC values of the OPFRs. The halogenated alkyl-OPFRs had lower log P_GC values than aryl-or alkyl-OPFRs. The bigger the molar volume was, the smaller the log P_GC value was. In addition, a quantitative structure-property relationship (QSPR) model of log P_GC versus different relative retention times (RRTs) was developed with a high cross-validated value (Q²_cum) of 0.946, indicating a good predictive ability and stability. Therefore, the log P_GC values of the OPFRs without standard substance can be predicted by using their RRTs on different GC columns.