Variation of coal extract structure with molecular mass

✍ Scribed by D.Gareth Richards; Colin E. Snape; Keith D. Bartle; Christopher Gibson; Michael J. Mulligan; Norman Taylor

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 775 KB
• Volume: 62
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(83)90314-9

✦ Synopsis

Asphaltenes and benzene-insolubles, and their methylated counterparts, of high-yield supercritical gas (SCG) and hydrogen donor solvent (HDS) extracts have been separated by size exclusion chromatography (SEC) on cross-linked polystyrene microspheres so as to investigate the variation in coal extract structure with molecular mass (MM). Narrow SEC fractions have been obtained which have been subjected to elemental, molecular mass (MM), functional group, n.m.r. and voltammetric analyses. The analytical results revealed that the MM range of the solvent fractions was 300 to z3000:With increasing MM the following trends were observed: aromaticity decreased, but the degree of condensation of aromatic nuclei did not vary significantly; the size of aliphatic substituents increased; and phenolic hydroxyl content decreased for SCG extract fractions but, in contrast, increased for HDS extract fractions. These variations about averages are considerable and demonstrate that caution is necessary in making use of analytical resultsfor grossfractions. Solubility in benzene of coal extracts resultsfrom low MM or from low polarity for higher MM materials.