Structural Features and Pyrolysis Behaviors of Extracts from Microwave-Assisted Extraction of a Low-Rank Coal with Different Solvents

Xiong, Yankun; Jin, Lijun; Yang, Li; Zhou, Yang; Hu, Haoquan

doi:10.1021/acs.energyfuels.8b03255

Cited by 24 publications

(10 citation statements)

References 52 publications

(100 reference statements)

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“…In the zones of 3000–3600 cm –1 , there was a relatively wide and mild absorption peak, which was mainly categorized as various types of hydroxyl or hydrogen bonds. The spectrum was further analyzed and fitted piecewise, and functional groups corresponding to each peak were classified. , …”

Section: Materials and Methodsmentioning

confidence: 99%

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Molecular Characterization of Henan Anthracite Coal

Liu

Jiang

2019

Energy Fuels

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A type of Chinese anthracite coal was analyzed by several analytical techniques such as Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), solid-state 13C nuclear magnetic resonance spectrum (NMR), and high-resolution transmission electron microscopy (HRTEM). Combining the experimental data, a reasonable macromolecular model of anthracite coal (C258H172O12N4S) was proposed. HRTEM results showed that the anthracite coal mainly contained aromatic laminates with different lattice sizes, with the length distribution characterized as 35.0% (<5.5 Å), 17.5% (5.5–7.4 Å), 22.5% (7.5–11.4 Å), and 10% (11.5–14.4 Å). The FTIR analysis suggested that ether, hydroxyl, and carbonyl groups were the main oxygenated functionalities. The ratio of these groups was approximately 4:3:3, which was consistent with the results of the XPS. On the basis of the rich analytical data, a three-dimensional molecular representation of the anthracite coal was constructed. Then, the properties of the model like NMR were simulated and exhibited a good agreement with the experimental spectrum in peak ranges and composition. The molecular model obtained in this work is useful for further studying the reaction mechanisms during the anthracite utilization processes, and the methodology adopted here can be extrapolated to other coal representations.

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Section: Materials and Methodsmentioning

confidence: 99%

“…The spectrum was further analyzed and fitted piecewise, and functional groups corresponding to each peak were classified. 33,34 2.2.1. Analysis of Oxygen-Containing Absorption Band.…”

Section: Methodsmentioning

confidence: 99%

Molecular Characterization of Henan Anthracite Coal

Liu

Jiang

2019

Energy Fuels

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“…Using the MAE method with CYC as the solvent, the extract yield can reach 8.0 wt % (the formula of the extraction rate is given in the Supporting Information ), which is higher than that of other solvents, and 1 h for NMH coal. 28 E CYC accounts for about 8.7 wt % of coal organic matter. The mass spectrum of LIAD-VUVPI-TOFMS of E CYC is shown in Figure 4 .…”

Section: Results and Discussionmentioning

confidence: 99%

Insights into a Low-Rank Naomaohu Coal Structural Information by Multistage Fractions Coupled with LIAD-VUVPI-TOFMS

Liu

Deng

et al. 2022

ACS Omega

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In-depth insights into the chemical composition and structural information of coal are an effective way to improve the efficiency of coal utilization. Laser-induced acoustic desorption coupling with vacuum ultraviolet photoionization time-of-flight mass spectrometry (LIAD-VUVPI-TOFMS) was applied to structural characterization of cyclohexane extracts of low-rank Naomaohu coal. The characterization of four types (12 model compounds) of mixed coal model compounds (three compounds per category)—saturated hydrocarbons, substitute aromatic hydrocarbons, aromatic hydrocarbons, and aromatic heteroatom rings—demonstrated that the approach can provide intact molecular weight information. The cyclohexanone extract ( E CYC ) was obtained by microwave-assisted extraction and separated into four group components (F1–4) by column chromatography to achieve component classification and simplify analysis. The molecular weight and structure were obtained by LIAD-VUVPI-TOFMS and synchronous fluorescence spectroscopy, combined with microwave-assisted extraction and column chromatography to separate product characteristics. Chemical components of a total of 248 species were observed, of which 46 are derived from aliphatic hydrocarbons embedded in the coal skeleton structure, 132 species are derived from aromatic hydrocarbons embedded in the coal skeleton structure, 61 are derived from possible coal skeleton units (compounds have obvious stacking and bonding effects), and 9 could not be determined (aromatic hydrocarbons or a possible coal skeleton structure unit).

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“…They found that the solvent− solute interactions significantly influenced the extraction with tetrahydrofuran and ethyl acetate. Xiong et al 24 compared the pyrolysis of coals, their Rs, and extracts. They found that the significant mass loss (ML) of the Rs at temperatures slightly higher than 200 °C could be ascribed to the release of the extracts by thermal degradation.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Structural Features of Hanglaiwan Subbituminous Coal and Its Residues from Solvent Extraction and Thermal Dissolution

Gao

Wei

et al. 2020

Energy Fuels

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Hanglaiwan subbituminous coal (HSBC) was subjected to solvent extraction (SE) with an isometric carbon disulfide/acetone mixed solvent (IMCDSAMS) to obtain a residue (RSE). Thermal dissolution (TD) of RSE was conducted in cyclohexane (CH) and ethanol (E), respectively, to afford residues R CH and R E . Both HSBC and the residues (Rs) were analyzed with multiple tools to understand their physicochemical properties. X-ray photoelectron spectroscopic analysis shows that >C–C<, >C–H, >C–OH, and >C–O– moieties are abundant in HSBC and Rs, while pyrrolic nitrogen (NP II) and sulfone are the main forms in which nitrogen- and sulfur-containing species exist, respectively, in the samples. According to the ultimate and Fourier transform infrared semiquantitative analyses, the aliphatic moiety-rich species obtained from the SE of HSBC with IMCDSAMS and contents of aliphatic moiety (AM)-rich species (AMRSs) obtained from the SE of HSBC with IMCDSAMS and AMRSs from the TD of RSE in CH are higher than those of aromatic ring (AR)-rich species (ARRSs). The ethylation of some ARs in RSE occurred during the TD of RSE in E. In addition, SE and TD increase the aromaticity of the resulting Rs. The mass loss (ML) decreases in the order of HSBC > RSE > R CH > R E in the temperature range of 30–400 °C, and the characteristic temperatures and maximum ML rates of the Rs are obviously higher than those of HSBC in the temperature range of 600–800 °C. These findings provide a scientific basis for the clean and efficient utilization of coals and their Rs.

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Structural Features and Pyrolysis Behaviors of Extracts from Microwave-Assisted Extraction of a Low-Rank Coal with Different Solvents

Cited by 24 publications

References 52 publications

Molecular Characterization of Henan Anthracite Coal

Molecular Characterization of Henan Anthracite Coal

Insights into a Low-Rank Naomaohu Coal Structural Information by Multistage Fractions Coupled with LIAD-VUVPI-TOFMS

Investigation on the Structural Features of Hanglaiwan Subbituminous Coal and Its Residues from Solvent Extraction and Thermal Dissolution

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