Comparison of UNIFAC and LSER Models for Calculating Partition Coefficients in the Hexane-Acetonitrile System Using Middle Distillate Petroleum Products as an Example

In this work, the possibility of using the two-phase hexane-acetonitrile system in gas chromatography analysis for the effective identification of middle distillate petroleum products containing polar organic compounds based on the example of diesel fractions variable in composition and delayed coking distillates is studied. The partition coefficient was calculated using the multiple internal standards based on petroleum products' compounds, which are primary representatives of different homologous series. Partition coefficients for 21 individual substances were calculated using this method. In addition, average partition coefficients were calculated for 23 different homologic groups of polyaromatic and heterocyclic compounds. The experimentally determined partition coefficients were compared with the coefficients calculated by group models-UNIFAC and the group version of the linear solvation energy relationship model. In the case of UNIFAC, different sets of parameters of both the classical model and the modified model were used. Based on a comparison of the results obtained, the optimal method for predicting the partition coefficients of petroleum products in the hexane-acetonitrile system was selected.

Automated summary

This study investigates the potential use of a two-phase hexane-acetonitrile system in gas chromatography analysis for identifying middle distillate petroleum products containing polar organic compounds. By calculating partition coefficients, the optimal method for predicting the partition coefficients of petroleum products in the hexane-acetonitrile system was determined.