An Observation on the Relation Between the Melting Points of the Disubstituted Isomers of Benzene and Their Chemical Constitution

Abstract

In an investigation of the melting points of the disubstituted derivatives of benzene, it was noticed that a definite relationship does exist between the melting point of the isomers and their chemical constitution.The derivatives were placed in one of two classes on the basis of their structure. Class A, in which the disubstituted derivative contains one ortho-para orienting group (1, 2, 6); and one meta orienting group (1,2, 6); and Class B, in which the disubstituted derivative contains two ortho-para orienting or two meta orienting groups.Division of Groups. The substituent groups were divided into two classes, those that are meta orienting and those that are ortho-para orienting in character. Table I lists the various groups according to these properties.The Order of the Melting Points for the Disubstituted Derivatives of Benzene.The following rules are postulated from the data collected on the melting points of the disubstituted derivatives of benzene: Rule I. When the disubstituted benzene derivative contains one meta orienting group and one ortho-para orienting group, the order of the melting points for the isomers is: ortho < meta < para.Rule II. When the disubstituted benzene derivative contains only orthopara orienting or only meta orienting groups, the order of the melting points for the isomers is: meta < ortho < para.In Table II are listed the melting points of various disubstituted derivatives of benzene containing one ortho-para orienting group and one meta orienting group.

Boiling Point and Melting Point Prediction for Aliphatic, Non-Hydrogen-Bonding Compounds

“…In the absence of experimental data, these properties must be estimated. There are a number of methods for estimating the boiling point or melting point from chemical structure (Abramowitz and Yalkowsky, 1990;Austin, 1930; Balaban et al, 1992;Beacall, 1928; Dearden and Rahman, 1988;Devotta and Pendyala, 1992;Holler, 1947;Stanton et al, 1992).…”

Learning Atomic Interactions through Solvation Free Energy Prediction Using Graph Neural Networks

“…In addition to the nature of the electronic factors between the solute and solvent atoms, intramolecular interactions affect the solvation free energies. For example, among the three isomers of dihydroxy benzene (1,2, 1,3, 1,4), 1,2-dihydroxy benzene was found to have the least boiling and melting points . This is possibly due to the intramolecular H-bonding in the 1,2-isomer and more stabilizing intermolecular interactions in the other two isomers.…”

“…For example, among the three isomers of dihydroxy benzene (1,2, 1,3, 1,4), 1,2-dihydroxy benzene was found to have the least boiling and melting points. 54 This is possibly due to the intramolecular H-bonding in the 1,2-isomer and more stabilizing intermolecular interactions in the other two isomers. This interpretation is demonstrated by the CIGIN model as well.…”

Orientation of Substitution in the Benzene Nucleus.

“…Probably because of a fortuitous correlation between the permanent polarity of the ring and field polarization, there is, as shown in table 3, a fair parallelism between the increasing orders of polarizing force and per cent of meta isomer produced in nitration. * Since there are two hydrogen atoms meta and three ortho-para to any particular reference position in the benzene ring, random unoriented replacements would go 40 per cent meta to the reference position.…”