A QSPR STUDY OF BOILING POINT OF SATURATED ALCOHOLS USING GENETIC ALGORITHM

Mohsen Kompany-Zareh

Institute for Advanced Studies in Basic Sciences, Zanjan 45195-159, Iran.

__Abstract __

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.