Topological Index and Thermodynamic Properties. II. Analysis of the Topological Factors on the Absolute Entropy of Acyclic Saturated Hydrocarbons

Abstract

Abstract The absolute entropy of acyclic saturated hydrocarbons is found to be well correlated linearly with the logarithm of the topological index (ZG) of the graph of the carbon atom skeleton as, S°=alogZG+b, excpet for sterically overcrowded and highly symmetrical molecules. This relation is improved by taking the symmetry factor σ into account as, S°=alogZG+b+clogσ. The physical meaning of these relations is clarified by analyzing the mathematical properties of ZG and the rotational partition function proposed by Pitzer.