A QSPR STUDY OF BOILING POINT OF SATURATED ALCOHOLS USING GENETIC ALGORITHM
Institute for Advanced Studies in Basic Sciences, Zanjan 45195-159, Iran.
A QSPR method is applied to study the boiling point of alcohols by the employment of the following properties: Schulz’s index, Randić’s connectivity index, Wiener’s number, surface area, volume, log P, molar refractivity, and polarizability. The idea behind the choice of these topological and physicochemical descriptors is to use realistic molecular quantities, which can, in principle, express all of the topological, electronic and geometric properties of molecules and their interactions. The boiling point values for a set of 44 alkanols were used, and by using a genetic algorithm (GA) coupled with partial least squares (PLS) method, all different possible relations between boiling point (bp) and the molecular properties up to the fourth order were examined and a group of multiple regression models with high fitness scores was generated. Using a backward elimination method on the top descriptors obtained from genetic algorithm, Randić’s index, surface area (grid), log of octanol-water partition coefficient, molecular refractivity, and polarizability were selected as significant descriptors. The analysis of computed data, and test of model for a validation set including 10 alcohols, shows that selected descriptors and selected order for each one are extremely well fitted tools for assessing the boiling point of alcohols. In particular, we have verified that using higher level relationships (i.e. square, cubic, and/or quadratic) in several-variable equations give excellent accuracy.