Fractionation of γ 1-Part of Pyridine Extract from Coal by Gel Permeation Chromatography and Structural Analyses of the Fractions

Abstract

Separation by gel permeation chromatography (GPC) and structural analyses of the GPC fractions were carried eut to gain an insight into the distribution of molecular weight, unit structure and molecular structure of coal and coal derivatives.Pyridine, chloroformpe oleum ether-soluble(1)part of Akabira coal was fractionated by the preparative GPC procedure into 14 fractions. The degree of GPC separation was estimated on the basis of molecular weight determined by vapor pressure osmometry (VPO)and of analyses of molecular weight distribution measured by analytical GPC method for cach fraction. From these analytical data, it was clearly found that the fractiens obtained by preparative GPC were separated in accordance with their respective molecular size and were of considerable narrow molecular weight distribution.The average struetural units of the individual fractions of preparative GPC were analysed by elementary analyses and by bonding types of hydrogen revealed by high resolution NMR. Using these structural parameter, the weight of average structural units (M(vs)) which were introdu ed as the new structural analysis were calculated There was a good agreement between the molecular weight estimated by VPO and weight of average structural units fer fractions No.5 to 14 having molecular weight under 400On the, other hand, coRsiderable discrepancies were observed in the results from both estimations for fractions No.2 to 4 of molecular weight ever 450. Considering these results, it may be concluded that the compound of r, part with molecular weight higher than about 450 consists of approximately a dimer or trimer of unit strueture, while individual unit structures with varying magnitudes exist as melecular structures of the cempound with rnolecular weight lower than 400. The results of structural analyses of GPC fraction are in agreement with the chemical structure of the solute which were assumed on the elution volumes by GPC separatioR behavior.