MASS-MODIFIED WIENER INDICES AND THE BOILING POINTS FOR LOWER CHLOROALKANES

Teik-Cheng Lim
Faculty of Engineering, Nanoscience and Nanotechnology Initiative, 9 Engineering Drive 1,
National University of Singapore, S 117576, Republic of Singapore

Abstract
A criterion for obtaining the chemical graph of a chloroalkane has been proposed by replacing the edge vertex containing CH₃ group with covalently bonded chlorine atom. By introducing a  as the group mass ratio of Cl to CH₃ as well as a molecular mass factor M=M(a, n, n_c), a mass-modified Wiener index has been proposed as W_m=M^PW where W is the Wiener index obtainable from the chemical graph, whilst n and n_c correspond to the number of chlorine and carbon atoms respectively in the chloroalkane molecule. The mass factor is defined in such a manner that  W_m=W for alkanes in order to maintain consistency. Numerical trials on the boiling point versus Wiener index plane reveal that when P=2 the chloroalkane curve shifts such that it coincides with the alkane curve. In view of the highly established empirical equation for alkanes it is suggested herein that, instead of obtaining separate empirical curves for haloalkanes, there is a good potential for boiling points of haloalkanes be obtainable based on the philosophy of mass factor in order to take advantage of the highly established empirical models of alkanes.

Key words: boiling points, chloroalkanes, mass modification, Wiener index