Chemical Structure of Fractions Obtained by Gel Permeation Chromatography for γ2-4 Part of Pyridine Extract from Coal

Abstract

The present paper describes the structure of solvent fractionation products from coal to clarify the relationship of molecular structure and structural units of coal constitution.Chloroform-soluble, petroleum ether-insoluble portion (γ2-4 part) of pyridine extract from akabira coal was separated into fractions according to their respective molecular weight by gel permeation chromatography (GPC) and the individual fractions obtained were analysed for structural units and molecular structure respectively using the results of high resolution NMR, elementary analyses and molecular weight. From these struc-tural analyses, the chemical structure of γ2-4 part were discussed.Each fraction showed good separation as indicated by narrow elution curves by analytical GPC and has s molecuular distribution from high molecular weight (M: 1910) to low molecular weight (M: 310) by increasing the elution volume (Fr. No.) of prepa-rative GPC. It is obvious from the analyese of structural parameters of an average unit structure which have approximately the same values except for the high molecular weight fraction, that each fraction consist of a constitution having a structural unit of homologus chemical structure.And also by taking into account the results of molecular weight, the average molecular structure f or each fraction were analysed. It was shown thown that the various structural parameters for aromatic rings and aliphatic structure substituted to aromatic rings per molecule increase gradually according to the shift from low molecular constitu-tions to high molecular constitutions.From these structural analyses, it may be said that the constitution of γ2-4 part consists of 2 or 3 aromatic rings which were substituted by the number of 2 or 3 aliphatic side chains having 3 carbon number in chain lengtn as its unit structure and were bounded repeatly by the number of 2 to 4 of these unit structures.