COAL SOLUBILITY AND SWELLING .1. SOLUBILITY PARAMETERS FOR COAL AND THE FLORY CHI-PARAMETER

This is the first of three papers that deal with coal solubility and swelling. An association model has been applied to coal, and this predicts that the mixing of coal with certain solvents will be determined by a balance between unfavorable “physical” interactions, measured by a Flory χ parameter, and favorable hydrogen bonding interactions. This first paper deals with the determination of χ from solubility parameters. Methods based on group contributions and swelling measurements are assessed. The former suffers from large errors while the latter does not give correct values because of large free-volume differences between coal and most solvents. Even though group contribution methods are flawed when applied to coal, they at least appear to give values in the right range. © 1990, American Chemical Society. All rights reserved.