Date of Graduation

1996

Document Type

Dissertation/Thesis

Abstract

The characterization of the semi-volatile organic content of coal and several N-methyl-2-pyrrolidinone (NMP) soluble coal extracts has been investigated using several analytical techniques, including gas chromatography mass spectrometry (GC/MS), Thermal Extraction (TE) GC/MS, Gel Permeation Chromatography (GPC), High Performance Liquid Chromatography (HPLC), Thermabeam LC/MS, Diffuse Reflectance FTIR (DRIFT), and Thermogravimetric (TGA) FTIR. Ultrasonic extraction was shown to be quicker than the traditional Soxhlet extraction technique as the first step in a solvent dissolution scheme for coal. The fractions resulting from the two techniques are similar based on characterization results obtained from HPLC, GPC, and TE-GC/MS experiments. TE-GC/MS was used to quantify the amount of NMP retained in several NMP-soluble coal extracts. The retained NMP ranged from 0.71% to 4.61% by weight. The limit of quantification was 0.015 {dollar}\\mu{dollar}g NMP. Six NMP-related compounds were identified in the NMP-soluble coal extracts that were not identified in the whole coals. TGA, TGA-FTIR, DRIFT, and TE-GC/MS were used to determine that activated carbon is a more suitable matrix for TE-GC/MS analysis of NMP than aluminum oxide, silica gel, or methanol. Thermabeam LC/MS was used to confirm that NMP-related compounds were thermal breakdown products of NMP heated in the presence of air. It was determined that these NMP-related compounds originated from either, (1) air present in the extraction vessel, or (2) reactions occurring between the whole coals and the NMP at the elevated temperatures used for the extraction. The combination of ultrasonic agitation with methanol and extended vacuum drying was successful for removal of the retained NMP from a NMP-soluble coal extract. Extrography was used to separate the NMP-soluble coal extracts into fractions based upon functionality, and the fractions were examined using DRIFT. The volatility of the fractions at 300{dollar}\\sp\\circ{dollar}C and at 800{dollar}\\sp\\circ{dollar}C, and the relative weight distributions of the fractions followed theoretical expectations. These analytical characterization techniques were successful in providing information which can be used to determine the final end-use of several NMP-soluble coal extracts.

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