Determination And Estimation Of Octanol/Water Distribution Coefficient Of Some Aromatic Hydrocarbon Derivatives

Benzoic acid derivatives, which are largely produced and widely used, may have polluted the water environment to various degrees and are considered as important priority contaminants. In order to evaluate the environmental contamination performance of benzoic acid derivatives, basic physical-chemical data must be known.The n-octanol/water partition coefficien(tlgK_ow) is the most important physical- chemical property of organic compounds, which is essential for understanding their environmental behavior and has become the hotspot and emphases problem in the international environment.The n-octanol/water partition coefficients of 3 substituted benzene derivatives containing halogen and 10 halogen benzoic acids at room temperature were measured by the shake-flask method.The fragment method is the most used method to estimate the lgK_ow. In order to make it more accurate and more convenient, lgK_ow of experiment of 367 substituted benzene derivatives were collected, and combined with the new data of this research, a new set of group values and factors were obtained to estimate the lgK_ow of substituted benzene derivatives by regression with least square method. The K_ow values of these 380 compounds were calculated by the fragmental method with new group values and new factors. Compared with the results calculated by K_owWin software, the average absolute error of lgK_ow and the average relative error of K_ow between calculated results and experimental results reduce 0.02 and 9%, respectively.A new set of group values and factors for estimate the lgK_ow of halogen benzoic acids can also be obtained using the same method. The lgK_ow of compounds participate in the regressive were estimated using the new group values and factors. Compared with the estimated results by the forgoing method and the results of K_owWin software, the average absolute error of lgK_ow using the new group values and factors reduces 0.03 and 0.06, respectively. And the new method has just 2 factors so it is very convenient to use.The calculate method was extanded to estimate the lgK_ow of non-aromatic compounds, and a new set of group values and factors were obtained. The K_ow values of these 314 compounds were calculated by the fragmental method with new group values and new factors. Compared with the results calculated by K_owWin software, the average absolute error between calculated lgK_ow and experimental lgK_ow and the average relative error of K_ow reduce 0.02 and 3%, respectively.