N-Methyl-2-pyrrolidinone (NMP) has been widely used as a solvent for extraction of coal and coal-derived materials partly because of the high extraction yields obtained with it. The literature contains dozens of articles that describe its use alone and in combination with carbon disulfide, tetracyanoethylene, and other solvents. Extractions have been performed using Soxhlet * To whom correspondence should be addressed.

PM 2.5 mass was measured daily with three batch samplers, a PM 2.5 R&P Partisol-Plus FRM, an Andersen RAAS, and a BYU PC-BOSS, and continuously with a TEOM monitor during July and August 2000. PM 2.5 composition was also determined. These data are part of an ongoing PM 2.5 characterization program centered around a sampling site at the National Energy Technology Laboratory Pittsburgh campus. The composition and concentrations of PM 2.5 were both highly variable during this time period. Likely sources of PM 2.5 during low concentration periods were transportation, coal-fired boiler, and other emissions generated in the local area. For these periods, the average concentration of PM 2.5 was 13 µg/m 3 and 70% of the PM 2.5 mass was carbonaceous material, including semivolatile organic material that was lost in varying degrees from both the TEOM and FRM samplers. In contrast, much higher concentrations of PM 2.5 were associated with transport of pollutants to the site. Analysis of meteorological and back-trajectory data suggests that these pollutants were emitted elsewhere during a period of high atmospheric pressure and were subsequently transported to the site with the passage of a frontal system. When the PM 2.5 collected at the site originated from the west or southwest, the concentrations averaged 31 µg/m 3 and ammonium sulfate averaged 54% of the PM 2.5 mass. Scanning election microscopy and trace element analyses are consistent with the association of high concentration PM 2.5 episodes with transport of coke and iron processing, coal-fired boiler, and other emissions from the Ohio River Valley region to the NETL site. Preliminary observations on the use of SEM and PIXE data in source apportionment at the NETL site are given.

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Partially codified, structurally intact latex fibers("Aflenhaar") found in a low-rank coal have been characterized by various analytical methods. It has been proposed in previous studies, and it appears to be so here, that the latex was "naturally" vulcanized during the coalification period. The Affenhaar samples studied here are high in sulfur. However, the sulfur constituents were not extracted in the pyridine solvent used to exact the hydrocarbons. Two fossilized latex samples recovered from different locations within the brown coal deposit were characterized. Pyridine extracts of the samples were analyzed by capillary gas chromatography, combined capillary gas chromatography-mass spectrometry, and high-resolution mass spectrometry. Twelve compounds in the extract were tentatively identified as amyrin and hopane biomarker derivatives by comparing the Kovats retention indices, mass spectra, and order of elution with those in the literature. Three of these. identifications were verified by cochromatography with authentic standards.Kovats retention indices for the twelve compounds are reported.

This paper describes a catalyst/wax separation technique based on dense-gas and/or liquid extraction of the soluble hydrocarbon components from the insoluble inorganic catalyst particles.The separation by extraction can also be performed in conjunction with magnetic separation of iron catalyst particles. Extractions of 4.91 wt % catalyst in wax were performed with n-butane, n-pentane, and n-hexane. Up to 91 wt % of the catalyst/wax feed mixture to the extractor could be recovered as a catalyst-free wax (combined yield of the second-and third-stage separators). High-temperature gel permeation chromatography was used to measure the average molecular weight of the extraction fractions. The extraction process separates the wax according to molecular weight. The lower molecular weight wax components are extracted from the catalyst/wax mixture and accumulate in the second-stage separator, while the higher molecular weight wax components remain in the first-stage separator. The low molecular weight wax fraction can be remixed with the catalyst and pumped back into the slurry reactor, reducing the average molecular weight, reducing the viscosity, and improving the transport properties of the reaction media while minimizing the chances of reactor gelation due to buildup of high molecular weight waxes.