Observation of Cyclopenta-Fused and Ethynyl-Substituted PAH during the Fuel-Rich Combustion of Primary Tar from a Bituminous Coal

Abstract

High-performance liquid chromatography (HPLC) with ultraviolet-visible (UV) diode-array detection was used to analyze the condensed-phase products from the fuel-rich combustion, at 1000 °C, of bituminous coal primary tar. Experiments were performed using a quartz two-stage reactor consisting of a fluidized-bed reactor coupled to a tubular-flow reactor. Eight cyclopentafused polycyclic aromatic hydrocarbons (CP-PAH) were identified, four of which have never before been observed as products of a bituminous coal and have also never been observed from the fuel-rich combustion of any coal: cyclopent[hi]acephenanthrylene, cyclopenta[cd]fluoranthene, dicyclopenta[cd,jk]pyrene, cylopenta[bc]coronene. In addition to these CP-PAH, two ethynylsubstituted PAH, 2-ethynylnaphthalene and 1-ethynylacenaphthylene, were identified for the first time as bituminous coal products. Yields of individual CP-PAH spanned a range of 4 orders of magnitude. Out of the eight CP-PAH identified, acenaphthylene was found to be the most abundant under all conditions investigated. CP-PAH of higher ring number were present in successively lower amounts, consistent with CP-PAH formation via hydrocarbon growth reactions. CP-PAH yields decreased with increasing oxygen concentration, indicating that rates of CP-PAH oxidation exceeded those of CP-PAH formation under the conditions investigated. Possible mechanisms of CP-PAH formation are discussed, but the complexity of the starting fuel precludes definitive delineation of the reaction pathways leading to CP-PAH and ethynyl-substituted PAH during the fuel-rich combustion of tar.

Bacterial mutagenicity of the three isomeric dicyclopenta-fused pyrenes: the effects of dicyclopenta topology

“…However, neither the benzaceanthrylenes nor the aceanthrylenes have been identified as constituents of the non-polar fraction of combustion exhausts [8]. Hence, 2 and in particular 3 represent the first two CP-PAH that were recently unequivocally identified in the non-polar fraction of combustion exhausts [11,12].…”

“…dicyclopenta[cd,mn]-(2), dicyclopenta[cd,fg]-(3) and dicyclopenta[cd,jk]pyrene (4, Fig. 1), which after their unequivocal synthesis [9,10] were identified as constituents of the non-polar fraction of combustion exhausts [11,12]. Hence, the availability of pure 2-4 now enables the assessment of their mutagenic response, which can be compared with that of 1 [3].…”

The effects of pressure on the yields of polycyclic aromatic hydrocarbons produced during the supercritical pyrolysis of toluene

“…Gas-phase toluene pyrolysis has been investigated by several researchers [16][17][18][19], but little is known about the pyrolysis of toluene under supercritical conditions. Likewise, most research on PAH formation pertains to the gas phase [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]; little has been done under supercritical conditions. Our supercritical toluene pyrolysis experiments make use of the reactor designed by Davis [36] and used by Stewart et al [4,14] for supercritical pyrolysis experiments with other model fuels.…”

Di-epoxides of the three isomeric dicyclopenta-fused pyrenes: ultimate mutagenic active agents

“…1), which were recently synthesized [4,17]. Their availability, subsequently, enabled their unequivocal identification as constituents of the non-polar fraction of combustion exhausts [18,19]. Compounds 2-4 have been also suggested to be formed as undesired products during the thermal removal of pyrene from contaminated soil [20].…”