Electrochemical Detection of Aliphatic Sulfur Compounds in Liquid Coal Extracts
The presence of sulfur compounds in coal is a serious environmental problem that affects the coal industry. This problem is due to the fact that organic sulfur is not separated or removed during any physical cleaning process. Organic sulfur is removed only during a more costly chemical desulfurizati...
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| Format: | Others |
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TopSCHOLAR®
1994
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| Online Access: | http://digitalcommons.wku.edu/theses/945 http://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=1948&context=theses |
| Summary: | The presence of sulfur compounds in coal is a serious environmental problem that affects the coal industry. This problem is due to the fact that organic sulfur is not separated or removed during any physical cleaning process. Organic sulfur is removed only during a more costly chemical desulfurization process. The kinds of organosulfur compounds in coal are generally known, but the quantity of each type of compound and the distribution of these compounds throughout the coal matrix has not been studied extensively. The objective of this research was to investigate the more reactive and chemically labile organosulfur compounds in liquid coal extracts. Organosulfur compounds such as sulfides, aliphatic thiols, and disulfides were studied using reverse phase HPLC with electrochemical detection in a acetonitrile/water mobile phase. Coal samples IBC 101 and IBC 105 were extracted with THF and hexane. The liquid coal extracts were fractionated using a simple chromatographic technique. The fractionated extracts were then analyzed using reverse phase HPLC with UV detection, reverse phase HPLC with EC detection, infrared spectroscopy, and selected chemical tests. From the data collected, one can conclude that THF and hexane solvents did extract organosulfur species that were detectable with UV and electrochemical methods. THF was found to be a better extraction solvent as compared to hexane. THF extraction resulted in an enrichment of the organosulfur compounds in the coal samples extracted. The chemical reaction for organosulfur compounds was positive in all fractionated samples collected, while IR analysis was negative or inconclusive. Reverse phase HPLC with EC detection appears to be an ancillary technique that has the potential to provide some pertinent information about organosulfur compounds in liquid coal extracts. |
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