Estimation of the acentric factor of organic compounds via a new group contribution method

Abstract

To predict the acentric factor of organic compounds, a new second order group contribution method is developed. Some changes are made in the functional groups of Joback and Reid method and these groups are employed as the first order functional groups in this work. Besides, some second order functional groups are considered to improve the accuracy of estimations and distinguish among most structural isomers and stereoisomers. A set of experimental data for the acentric factor of 608 organic compounds containing complex and heavy polycyclic aromatic components are used to determine the group contribution values of 122 functional groups. The collected compounds in this research are hydrocarbons and hydrocarbon derivatives include carbon, hydrogen, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, and iodine atoms. The MATLAB software is utilized to develop the new model. The average absolute deviation of acentric factor predictions for 608 organic compounds is 0.022 and the percentage of average absolute relative deviation is 4.9%. The results of the new method are compared to the Constantinou, Gani and O'Connell method. It is observed that there is a considerable difference in the accuracy of the new method in comparison to that of the mentioned method.