Analytical Method for the Determination of the Distribution of Sulfur Functional Groups in American Coals.

摘要

All organic sulfur in mature coals is believed to be bivalent and spread throughout the organic matrix. The most important forms in which organic sulfur appears are dibenzothiophenes, thiophenes, aliphatic sulfides, thiols, and thiophenols. Direct determinations of the abundance of the various organic sulfur groups in coal show that the thiols and thiophenols combined typically range from 10 to 60% of the organic sulfur while aliphatic (plus arylsulfides, which are usually low in concentration) range from 10 to 40%, and thiophenes as calculated by difference range from 10 to 75%, being greater than 30% in most coals. Examples of two coals with a high percentage (77%) of their organic sulfur in aromatic rings, are Illinois No. 6 bituminous coal and Texas lignite (Milam Co.). In the former coal 27% of the organic sulfur is in the form of aliphatic sulfides and 42 and 31% in the form of single ring thiophenes and dibenzothiophenes, respectively. In the lignite about 57% of the organic sulfur was in the form of single thiophene structures and 16% in the form of dibenzothiophenes. Since each organic group reacts at a different rate, the distribution of organic sulfur groups can have a profound effect on the rate of coal desulfurization. For example, more organic sulfur remains in products from coal liquefaction when thiophenic structures predominate in the organic sulfur than when organic sulfides predominate. (ERA citation 08:013715)