Characterization of Biomarkers and Structural Features of Condensed Aromatics in Xianfeng Lignite

Xianfeng lignite (XL) was sequentially extracted under ultrasonication at room temperature with petroleum ether, carbon disulfide (CDS), methanol, acetone, and isometric CDS/acetone mixed solvent to afford extracts 1–5, respectively. The mixed solvent-inextractable portion was sequentially extracted with cyclohexane, benzene, 1-methylnaphthalene, methanol, and ethanol at 320 °C to afford extracts 6–10, respectively. The extracts were analyzed with a gas chromatography/mass spectrometer (GC/MS) to characterize biomarkers in XL. The biomarkers were significantly enriched in extracts 1 and 6. They can be classified into a series of <i>n</i>-alkanes, isoprenoid alkanes, terpenoids, <i>n</i>-alkenes, methyl alkanones, <i>n</i>-alkylbenzenes, <i>n</i>-alkyltoluenes, and <i>n</i>-alkyl-<i>p</i>-xylenes. The biomarker distributions provided important information on the main origin of organic matter in XL. Related mechanisms for the formation of biomarkers during coalification were discussed. The residue from sequential thermal extraction was subjected to ruthenium-ion-catalyzed oxidation along with subsequent product analyses with GC/MS and direct analysis in a real-time ionization source coupled to a time-of-flight mass spectrometer (DARTIS/TOFMS) to understand its structural features. The results show that the residue is rich in condensed aromatics (CAs) and methyl is the dominant alkyl side chain on aromatic rings. The aromatic rings in the residue are mainly connected by −(CH₂)₃– and −CHCH₃(CH₂)₂–. DARTIS/TOFMS analysis suggests that CAs with alkyl-substituted biphenyl and alkyl-substituted phenylbiphenyl skeletons also exist in the residue. This investigation provides an effective approach for understanding biomarkers and the structural features of the macromolecular network in XL

Structural Characterization of Typical Organic Species in Jincheng No. 15 Anthracite

The structures of typical organic species in Jincheng No. 15 anthracite (J15A) were characterized by solid-state ¹³C nuclear magnetic resonance, X-ray photoelectron spectrometry, X-ray diffraction, and Fourier transform infrared spectrometry in combination with gas chromatography/mass spectrometry and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry analyses of the resulting soluble organic species from ruthenium-ion-catalyzed oxidation (RICO) of J15A. The results show that the typical organic species in J15A are condensed aromatics, along with small amounts of methyl group as the dominant side chain on the condensed aromatic rings (CARs) and methylene linkage connecting the CARs. Every aromatic cluster contains five rings on average, and the substituted degree of each aromatic ring is very low. In addition, J15A is rich in <i>peri</i>-condensed aromatics but poor in <i>cata</i>-condensed aromatics and polyaryls. The oxygen functional groups in J15A include C–O and >CO groups. Pyrrolic nitrogen species and arylthiophenes are the main organic nitrogen and sulfur species in J15A, respectively

Poplar Liquefaction in Water/Methanol Cosolvents

Poplar liquefaction (PL) in methanol, water, or water/methanol cosolvents (WMCSs) was investigated at 240–320 °C for 0–90 min. The results show that the yields of bio-oils (BOs) obtained from PL in WMCSs are higher than those in either methanol or water, indicating that methanol has a synergic effect with water on PL. The maximum BO yield of 44.2% was obtained at 270 °C for 15 min in a WMCS containing 70 vol % water. The BOs were analyzed with a gas chromatograph/mass spectrometer (GC/MS) and Fourier transform infrared (FTIR) spectrometer. Poplar and its residues were analyzed with the FTIR spectrometer and a scanning electron microscope (SEM). The fiber structure of poplar was significantly destroyed during PL in WMCS based on the SEM observation. According to GC/MS analysis, the BOs mainly consist of hydrocarbons, phenols, furans, other ethers, aldehydes, ketones, carboxylic acids, esters, and nitrogen-containing organic compounds. Among of them, phenols, ketones, and esters are the main group components. To investigate the liquefaction mechanism, the three major components in biomass, i.e., cellulose, hemicellulose, and lignin, were subjected to degradation in the same solvents. The results suggest that WMCS exhibits better synergic effects for cellulose and hemicellulose than for lignin. Further investigations are needed for a detailed mechanism on synergic effects

Characterizations of the Extracts from Geting Bituminous Coal by Spectrometries

Geting bituminous coal (GBC) was sequentially extracted with petroleum ether, carbon disulfide (CDS), methanol, acetone, and isometric CDS/acetone mixed solvent at room temperature to afford extracts 1–5 (E₁–E₅) and residue. Detailed characterizations of the extracts were performed with a gas chromatography/mass spectrometer (GC/MS), Fourier transform infrared (FTIR) spectrometer, and direct analysis in real-time ionization source (DARTIS) coupled to an ion-trap mass spectrometer (ITMS). GBC and its residue were also analyzed with the FTIR spectrometer. Particle sizes of the residue were significantly reduced compared to those of GBC according to the observation with a scanning electron microscope. Arenes with 1–4 rings and more condensed arenes were enriched into E₁ and E₂, respectively, while more heteroatom-containing organic species were detected in other extracts, especially in E₃ and E₄ according to GC/MS analysis. The extracts, especially E₁–E₄, contain more aliphatic moieties and less aromatic moieties compared to GBC and its residue based on FTIR analysis. DARTIS/ITMS proved to be a powerful tool for analyzing thermally labile and/or involatile species, which are difficult to be identified with GC/MS, in the extracts

Structural Features of Extraction Residues from Supercritical Methanolysis of Two Chinese Lignites

The methanol-insoluble portions from supercritical methanolysis of Shengli lignite (SL) and Huolinguole lignite (HL) were extracted with an isometric carbon disulfide/acetone mixed solvent under ultrasonic irradiation to afford extracts and extraction residues (ERs). The ERs were subjected to ruthenium-ion-catalyzed oxidation, and soluble portions were separated from the reaction mixture and esterified. The resulting products were analyzed with a gas chromatography/mass spectrometer and atmospheric solids analysis probe/time-of-flight mass spectrometer to reveal structural features of heavy species in the two lignites. The results show that the ER from SL is richer in highly condensed aromatic species than that from HL, while both ERs have the same carbon number range (C₉–C₂₄) of alkyl groups with the highest content at C₁₅ on aromatic rings and the same distribution of alkylene bridges (C₂–C₂₀) connecting aromatic rings with a higher abundance of shorter linkages than that of longer linkages