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A lignite monomer of organic oxygen (LMO) and a lignite monomer of organic nitrogen (LMN) were constructed based on the occurrence forms of organic oxygen/nitrogen in lignites, then their intermolecular hydrogen bonding interactions (HBIs) with water molecules were investigated using the density functional theory (DFT) and the quantum theory of atoms in molecules (AIM). The results show that a variety of LMO-(H 2 O) n ( n = 1–16) and LMN-(H 2 O) n ( n = 1–12) complexes were formed. A water cage cluster containing 16 water molecules and a water film cluster containing 10 water molecules were observed in LMO-(H 2 O) 16 and LMN-(H 2 O) 12 complexes, respectively, and cyclic water tetramers were the dominated existing form of water clusters. The ratio of hydrogen bonding energy (HBE) among water molecules to the total HBE in lignite ⋯ water complexes gradually increases with the number of water molecules increasing, and the ratios are 84% and 44% in LMO-(H 2 O) 16 and LMN-(H 2 O) 12 complexes, respectively. The intermolecular HBIs in LMO-(H 2 O) 12 and LMN-(H 2 O) 12 complexes can be divided into purely weak and medium closed-shell non-covalent interactions. Molecular electrostatic potential analyses imply that the most formation sites of hydrogen bonds are transferred to the O atoms of water molecules from the O and N atoms in LMO and LMN with the number of water molecules increasing in LMO-(H 2 O) n and LMN-(H 2 O) n complexes. [ABSTRACT FROM AUTHOR]

To investigate the molecular composition of soluble organic species in Baiyinhua lignite (BL) and their evolution profiles during pyrolysis, BL was firstly pyrolyzed in a fixed-bed reactor, affording gaseous products, tars and chars, then BL and its chars were thermally dissolved in supercritical methanol affording soluble portions (SPs). The composition and structural characteristics of the SPs and tars were analyzed with a gas chromatograph/mass spectrometer. The results indicate that most of the soluble organic species can be released from BL below 500 °C during pyrolysis. Abundant soluble long-chain aliphatic hydrocarbons and carboxylic acids wrap around the aromatic nucleus in BL. According to the difference between the composition and structural characteristics of the SPs and tars, the evolution profiles of the soluble organic species from BL pyrolysis were discussed in detail. [ABSTRACT FROM AUTHOR]

Shengli lignite (SL) was subjected to sequential extraction (SE) with carbon disulfide, benzene, methanol, acetone, and tetrahydrofuran under ultrasonication to afford extracts 1–5, respectively, and the residue (R SE , i.e., residue from SE). The R SE was subjected to sequential thermal dissolution (STD) in benzene, methanol, and acetone in a batch autoclave from 210 to 330 °C to afford soluble portions (SPs) and the residue (R STD , i.e., residue from STD). The total yield of extracts 1–5 is only 2.86%, while the yields of SPs from STD in benzene, methanol, and acetone are 5.69%, 10.15%, and 48.41%, respectively. The SPs from STD in benzene and methanol mainly consist of hydrocarbons and phenols, while ketones are the main compounds detected in the SP from STD in acetone and most of nitrogen-containing organic compounds appear in the SP from STD in acetone. During STD in acetone, acetone conversion to phorone, isophorone, and their derivatives was confirmed. [ABSTRACT FROM AUTHOR]

In this paper, two typical Chinese lignites, Shengli lignite (SL) and Xiaolongtan lignite (XL), with different geologic ages were firstly thermal dissolved in sub- and supercritical benzene and ethanol, then soluble organic species were analyzed with Fourier transform infrared spectroscopy (FTIR), gas chromatograph/mass spectrometer (GC/MS) and atmospheric solids analysis probe/time of flight mass spectrometer (ASAP/TOF-MS). The soluble organic species yield of XL in benzene is close to that of SL in the temperature investigated, whereas the soluble organic species yield of XL in ethanol is obviously higher than that of SL at high temperature region. Obvious difference exists in the molecular composition of the soluble organic species between SL and XL. The soluble organic species of XL contain more free aliphatics but less arenes than those of SL. The arenes in the soluble organic species of XL are mainly composed of the derivatives of benzene and naphthalene, while those from SL are dominated with condensed arenes and polycyclic biphenyls. Furthermore, the free oxygen-containing organic species in SL and XL are dominated with ketones and phenols, respectively. Additionally, ASAP/TOF-MS analysis indicates that the molecular weight of soluble organic species from SL is higher than that from XL. [ABSTRACT FROM AUTHOR]

During pyrolysis, the intrinsic organic species in coals play an important role on the formation of tar but the relationship between them has not been elucidated in detail. In this study, the composition and structural characteristics of pyrolysis tars and soluble portions (SPs) via thermal dissolution from Baoqing lignite were analyzed with Fourier transform infrared spectroscopy (FTIR), gas chromatograph/mass spectrometer (GC/MS) and quadrupole/Orbitrap mass spectrometer (Orbitrap MS), and the formation mechanisms of main components in pyrolysis tars were proposed. FTIR analyses showed that both the SPs and tars are rich in -OH, C O, aromatic C C, C-O, aliphatic and aromatic C-H functional groups, suggesting they are partially similar in composition and structure. GC/MS and Orbitrap MS analyses indicated that a part of soluble organic species was directly volatilized into the tars, while others were suffered from complex reactions during pyrolysis, such as the cleavage of bridged bonds, the decomposition of oxygen-containing functional groups and the condensation of aromatics. Compared with the SPs, the higher contents of CH and O 1 classes but lower contents of O 2 -O 6 classes in the tars demonstrated that the soluble organic species are partially or completely deoxygenated during pyrolysis. [Display omitted] ● The yield of pyrolysis tars is obvious lower than that of soluble organic species. ● The components of tars are very closely related to soluble organic species. ● A part of soluble organic species is directly volatilized into pyrolysis tars. ● The soluble organic species were subjected to deoxygenation during pyrolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe/NC catalyst shows good activity and stability for cleaving C-O bonds in lignite. • Fe-N and Fe/Fe 3 C species in the catalyst were crucial to the catalytic activity. • Active hydrogen species were hydrogen radicals generated from H 2 and isopropanol. • The hydrocracking products have higher H/C ratio and heating values than lignite. • Catalytic hydrocracking promoted producing phenols via the cleavage of C-O bonds. Cleaving C-O bridged bonds of lignite via catalytic hydrocracking (CHC) is an effective method to produce chemicals and clean fuels. Herein, a nitrogen-doped carbon supported Fe catalyst was developed by using a one-pot method for CHC of Xilinguole lignite (XL) and its related model compounds. The doped nitrogen enhanced the interaction between Fe and N species to form Fe-N sites and favored forming smaller Fe/Fe 3 C nanocrystals, which played a crucial role in CHC performance. Toluene and phenol were produced from CHC of benzyl phenyl ether (BPE) with high yield and selectivity at 250 °C over the optimal catalyst with 4% Fe, without hydrogenation products. The Fe-based catalyst activated both H 2 and isopropanol to generate hydrogen radicals for cleaving C-O bridged bonds. The CHC of XL under different temperature and time showed that the yields of oil, asphaltene and preasphaltene were obviously promoted under 325 °C, 1 MPa, and 6 h, and they had much higher H/C ratio but remarkably lower O/C ratio, resulting in much higher heating values (28.19–36.90 MJ/kg) than XL. Phenols were the major group component with relative content of 53.6 wt% in oil from CHC, and the asphaltene and preasphaltene from CHC had obviously lower molecular weights, which could attributed to depolymerization of C-O bridged bonds in the XL macromolecular structures over the catalyst. [ABSTRACT FROM AUTHOR]

Ni and Zr modified nanosheet ZSM-5 zeolites as tandem catalysts were designed using co-impregnation method (Zr-Ni/S-Z5) or combining in-situ hydrothermal synthesis of Ni@S-Z5 and sequential impregnation of Zr (Zr/Ni@ S-Z5). Their applications in upgrading of lignite pyrolysis volatiles coupling with methanol to light aromatics were investigated. The results demonstrated that nanosheet zeolites with larger surface areas and shorter b-axis length benefited the production of light aromatics due to exposing more active sites and improved diffusion limitation compared with conventional ZSM-5 zeolites. Adding Ni and Zr into tandem catalysts further enhanced BTEXN yields, which was attributed to the induction of oxyphilic ZrO 2 for activating C Ar -O bonds combining the promotion of Ni for hydrogenation. Comparing to Zr-Ni/S-Z5 catalyst, lower BTEXN yield was observed due to the decrease in exposing active sites over Zr/Ni@ S-Z5 catalyst. Moreover, enhancing diffusion behaviors in shorter b-axis length and the presence of more fractions of external coke indicated less effective in blocking pore channels, thus nanosheet zeolite series showed lower deactivation rates. [Display omitted] • Nanosheet zeolites with larger surface areas and shorter b-axis benefited the production of light aromatics. • Adding Ni and Zr into tandem catalysts further enhanced BTEXN yields. • Nanosheet zeolites with more fractions of external coke presented lower deactivation rate. [ABSTRACT FROM AUTHOR]

Rationale: Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) was applied to the characterization of organic compounds in coal extracts at the molecular level. Large volumes of data obtained by FT‐ICR MS were processed via statistical methods to extract valuable information on the molecular structures and compositions of organic compounds in coal. Methods: A low‐rank coal was subjected to ultrasonic extraction sequentially with six solvents to separate and enrich species with different molecular characteristics. Complex mass spectra of the six extracts were obtained by a FT‐ICR MS system equipped with two ionization sources. Two multivariate statistical methods, hierarchical clustering analysis (HCA) and principle component analysis (PCA), were introduced to mine useful information from the complex MS data and visually exhibit comprehensive molecular details in coal extracts. Results: Similarities and differences between the 17 MS data sets from six coal extracts ionized by different ion sources were visually exhibited in plots via data processing using HCA and PCA. For HCA, all of the identified compounds were divided into seven classes (CH, O, N, S, ON, OS, and NS), and detailed differences in the relative abundance were revealed. In addition, PCA discriminated the differences in molecular composition for organic compounds from the six extracts. Conclusions: Multivariate statistical analysis is a promising methodology which can interpret the chemical composition of coals and coal derivatives at the molecular level, especially for the analysis of multiple complex samples presenting in a single plot. [ABSTRACT FROM AUTHOR]

Highlights • HCA and EMGM are introduced to reach in-depth statistic results for coal extracts. • The similarities and differences of clusters are visually exhibited in a plot via HCA. • Molecular structures in the same EMGM model have a certain similarity. Abstract A coal was extracted and thermally dissolved with cyclohexane, acetone and methanol sequentially. The ultrasonic extracts and thermal dissolution (TD) products were analyzed using an Orbitrap mass spectrometer (MS) with an atmospheric pressure chemical ionization source in positive ion mode. Large amounts of MS data were obtained but there were challenges in obtaining meaningful information from the data. The purpose of cluster analysis is to reduce complex multivariate data into meaningful groups. Two cluster analysis methods, hierarchical cluster analysis and expectation maximum algorithm based on Gaussian mixture model (EMGM), run by R language were introduced to obtain in-depth statistical results for compounds in both extracts and TD products. Seven types of heteroatomic compounds (O 1 , O 2 , N 1 , S 1 , O 1 N 1 , O 1 S 1 and N 1 S 1) in the extracts under the condition of ultrasonic extraction with cyclohexane were clustered with EMGM and possible structures of the related models can be inferred by analyzing the relationship between carbon number and double bond equivalent. The application of cluster analysis will provide methodological guidance in studying the structure of coal molecules. [ABSTRACT FROM AUTHOR]

Thermal dissolution (TD) plays an important role in obtaining soluble components from low-rank coals. Characterization of the TD product is essential for both optimization of TD conditions and in-depth understanding of molecular structures in coal that is crucial for the refining processes. In-source collision-activated dissociation (ISCAD) combined with high-resolution mass spectrometry (MS) was employed in this study to analyze four TD products of a low-rank coal obtained by using cyclohexane, acetone, methanol and ethanol as solvents. ISCAD-MS allows the evaluation of distributions of oxygen and nitrogen atoms located within aromatic cores or on alkyl chains based on the abundances of heteroatom-containing precursor ions and fragment ions. In addition, ISCAD-MS can evaluate the abundance of multi-core compounds based on the change of average double bond equivalent value upon fragmentation. These structural details advance the current understanding of the TD products at the molecular level. [ABSTRACT FROM AUTHOR]

Dayan lignite (DL) was subjected to thermal dissolution sequentially with cyclohexane, acetone and methanol to obtain three filtrates. The filtrates were characterized by Fourier transform infrared spectroscopy, gas chromatography/mass spectrometry (GC/MS), and time-of-flight mass spectrometry (TOF-MS) equipped with atmospheric pressure photoionization (APPI), electrospray ionization (ESI) or direct analysis in real time (DART) to understand the structural features of DL. Aliphatic hydrocarbons, furans and alcohols were enriched in the filtrate of cyclohexane, acetone and methanol, respectively, according to the data of GC/MS. One ring aromatics was also identified by GC/MS as major species in the three filtrates. Both GC/MS and APPI-MS can well analyze compounds with low polarity, but APPI-TOF-MS in this work successfully characterized polycyclic aromatics and extended the measurement range (molecular weight and ring size) of GC/MS. ESI-TOF-MS is suitable to analyze polar compounds in coal. Data from ESI-TOF-MS indicated that heteroatom compounds including non-aromatics and aromatics with 1-2 rings are the major polar components in DL. As an ambient MS ionization method, DART shortened the analysis time without sample pretreatment and more aromatics over 4 rings were identified by DART-TOF-MS. Characterization of the complex coal filtrates with multiple mass spectrometers provided a full view of the molecular information of DL. [ABSTRACT FROM AUTHOR]

Detailed characterization of organic components in low-rank coals is essential for the utilization of coals in clean, effective and value-added ways. Two kinds of low-rank coals were subjected to sequential thermal dissolution in the order of cyclohexane, acetone, and methanol to obtain six soluble portions (SPs) from the coals. Two gas chromatographic systems, gas chromatography/mass spectrometry (GC/MS) and comprehensive two dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF MS), were applied to the characterization of the SPs. Compared to GC/MS, a routine analytical technique for complex mixtures, GC × GC/TOF MS improves the separating power, overcomes the co-elution, and reveals more structural details in complex mixtures like coals. Low-polar compounds like aliphatic hydrocarbons and arenes tended to be extracted by cyclohexane. High content of polar alcohols and phenols were identified in the SPs of methanol. Acetone could enrich nitrogen-containing organic compounds (NCOCs) due to hydrogen bond of N–H⋯O between NCOCs and acetone. Additionally, a series of low-concentration species including some isomers in the SPs were only identified by GC × GC/TOF MS. Distributions of various classes of compounds on the two-dimensional total ion chromatograms plot were discussed according to the separation mechanism of the two columns. Detailed analysis of biomarkers was also exhibited and discussed. [ABSTRACT FROM AUTHOR]

Lignite is rich in oxygen-containing species (OCSs) and able to load Ni via ion exchange to prepare Ni/C catalyst. However, the OCSs usually exists in the form of organic salts, which can reduce the capacity of Ni ion exchange. In this paper, Shengli lignite (SL) was treated with HCl and HCl/HF to selectively remove the organic salts and insoluble minerals, respectively, and the modified lignite was oxidized by H 2 O 2 to further increase the carboxyl content. The treated lignite was used to prepare Ni/C catalyst and the activity for biomass volatile reforming was evaluated. The results show that demineralization (DM) caused the corrosion of pore structure of SL and gave a Ni/C catalyst with a low specific surface area (SSA) of 222.1 m 2 /g. Oxidation with H 2 O 2 further destroyed the structure of DMSL and provided a Ni/C with the lowest SSA of 141.1 m 2 /g. Acid wash (AW) with HCl resulted in the increase of ion exchange capacity of SL and gave a Ni/C catalyst with larger SSA, higher loading, lower particle size and well dispersion of Ni particle in comparison with SL and DMSL. H 2 O 2 treatment of AWSL significantly increased the amount of carboxyl group to 3.8 mmol/g and gave a Ni/C with the largest SSA of 291.1 m 2 /g, highest Ni loading of 17.3% and smallest Ni crystallite size of 3.4 nm, as well as most active for corncob volatile reforming. [ABSTRACT FROM AUTHOR]

A series of carbon disulfide/acetone mixtures were used to extract organic species from Shengli lignite, a Chinese coal. Orbitrap mass spectrometry coupled with electrospray ionization was used to characterize the molecules in the extracts. Heteroatomic species, including oxygenates, nitrogenates, and sulfonates, were determined. Pure carbon disulfide or acetone had the lowest extraction for oxygenates while the mixtures increased the relative abundance of oxygenates. From the value of the double bond equivalence, the compounds with 1 oxygen contained the highest concentrations of aromatics and aliphatics, but compounds with 6 were aliphatic with a double bond equivalence of 3. For compounds containing 2 oxygens, aromatics with one ring were present at the highest concentrations in the 1:1 carbon disulfide:acetone extract. For compounds containing 3, 4, and 5 oxygens, most aromatic species were identified with double bond equivalence values between 4 and 6, showing the presence of an aromatic ring. The results indicated that the solvent mixtures enhanced the extraction of oxygenates from Shengli lignite. [ABSTRACT FROM PUBLISHER]

Shengli lignite (SL) was oxidized and depolymerized in aqueous sodium hypochlorite under mild conditions followed by sequential extraction with ethoxyethane and ethyl acetate. The extracts were analyzed by Fourier transform infrared spectroscopy, gas chromatograph/mass spectrometry (GC/MS), time-of-flight mass spectrometry (TOF-MS) equipped with electrospray ionization (ESI), and direct analysis in real time (DART) to understand the structural features of SL. In total, 130, 272, and 818 compounds were identified by GC/MS, ESI-MS, and DART-MS, respectively, and the corresponding molecular mass distributions are between 70 and 322, 114 and 664, 113 and 753 u , respectively. GC/MS detected molecules with low molecular mass and polarity, and the major species include aliphatic acids, benzene polycarboxylic acids, chloro-substituted species and nitrogen-containing compounds. A large number of heteroatom-containing compounds (oxygen, nitrogen and sulfur) with relatively high molecular mass and unsaturation degree were determined using ESI-MS. As an ambient ionization technique, DART speeded up the analysis time with little or no sample pretreatment. Compared to the other two MS techniques, DART-MS broadened the measurement range, and O x N 5 , and O x N 6 classes were only detected by DART-MS. [ABSTRACT FROM AUTHOR]

Dongming lignite was sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and isometric carbon disulfide/acetone mixed solvent at room temperature to afford extracts 1-5, respectively. High-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry was used to separate and characterize heteroatomic species in the extracts at molecular level. Molecular mass of compounds in the extracts is mainly distributed from 300 to 800 u, and the relative abundance of compounds with molecularmass over 800 u in the carbon disulfide extract is 135 times of that in the petroleum ether extract. The acetone extract has the highest relative abundance for organonitrogen compounds. Double bond equivalence numbers of detected species indicate that most of the organonitrogen compounds contain N-heterocyclic aromatic rings, including pyridine, quinoline and pyrrole. Some organonitrogen isomers in Dongming lignite were separated and identified by high-performance liquid chromatography coupledwith electrospray ionization time-of-flight mass spectrometry, and the corresponding structural information was proposed. [ABSTRACT FROM AUTHOR]

A novel catalyst was prepared by loading nickel on Shenli lignite char via ion-exchange. The results show that the nickel crystallite size (NCS) and specific surface area (SSA) of the catalyst significantly depended on solution pH and carbonization temperature. The catalyst prepared in pH 11 at 650 °C reached the maximum SSA of 236.3 m 2 /g and the nickel particles dispersed quite well in the catalyst with a NCS of 5.6 nm. The catalyst was used for corncob volatiles reforming in a two-stage fixed-bed reactor to study the effects of temperature, steam, and space velocity on gas yields and carbon distributions. It effectively improved tar decomposition at 650 °C under inert atmosphere and produced a tar-free syngas in a yield of 43.9 mmol/g, which is higher than that over a commercial Ni/Al 2 O 3 . The increase of the NCS during catalytic reforming above 650 °C leads to the catalyst deactivation for tar decomposition. The study revealed the possibility of using Ni/char as a potential catalyst for low-temperature gasification of biomass. [ABSTRACT FROM AUTHOR]

Two Chinese coals, Shengli lignite and Shenmu–Fugu subbituminous coal, were subjected to non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) in cyclohexane at 300 °C for 3 h under pressurized hydrogen using a solid acid as the catalyst, which was prepared by impregnating isometric pentachloroantimony and trimethylsilyl trifluoromethanesulfonate into an activated carbon. The reaction mixtures from both NCHC and CHC were sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and isometric acetone/carbon disulfide mixed solvent to afford extracts 1–5 (E 1 –E 5 ). The results show that both E 1 and total extract yields from CHC are appreciably higher than those from NCHC of each coal. E 1 from either NCHC or CHC of each coal was analyzed with a gas chromatograph/mass spectrometer (GC/MS) and an atmospheric solids analysis probe/time of flight mass spectrometer (ASAP/TOF-MS). GC/MS analysis shows that each E 1 consists of alkanes, arenes, and oxygen-containing organic compounds (OCOCs), and most of the arenes are methyl-substituted ones, whereas alkenyl groups only appear on benzene ring; most of the OCOCs are arenols, especially alkylarenols. According to ASAP/TOF-MS analysis, organic compounds with molecular masses ranging from 500 to 950 u appear in E 1 from CHC of both coals. [ABSTRACT FROM AUTHOR]

A three-step degradation, including sequential ultrasonic extraction (UE), sequential thermal extraction (TE), and ruthenium ion-catalyzed oxidation (RICO), of Xianfeng lignite (XL) was performed to characterize the organonitrogen species (ONSs) in XL. More than 87.3% of organic matter in XL was converted into soluble portions through the degradation. The analysis with X-ray photoelectron spectrometer shows that pyrrolic, amino, and quaternary nitrogen species are the main nitrogen forms both in XL and its residue from UE, while nitroaromatics, chemisorbed N-oxides, and pyrrolic nitrogen are predominant in the residue from TE. A series of ONSs, including pyridines, quinolines, benzo[d]imidazoles, and arylamines, were identified in the extracts from TE of the UE residue according to GC/MS analysis. Among the ONSs, pyridines and quinolines are the most abundant. The ONSs could be released by thermally destroying noncovalent bonds, such as hydrogen bonds and aromatic π-π interactions, during TE of the UE residue. Most of ONSs released from RICO of the TE residue could be generated from the degradation of nitrogen-containing macromolecular aromatics in XL matrix (XLM). Nitrobenzenecarboxylic acids are the most abundant ONSs released from RICO of the TE residue and should be released by the degradation of macromolecular nitroaromatics in XLM. [ABSTRACT FROM AUTHOR]

A highly dispersive Fe/ZSM-5 as the precursor of Fe-S/ZSM-5 was prepared by decomposing Fe(CO)5 onto ZSM-5 zeolite at 250°C. Shengli lignite (SL) was isolated to extractable portion (EP) and extraction residue (ER) by exhaustive extraction with isometric carbon disulfide/acetone mixed solvent (IMCDSAMS) under ultrasonic irradiation. The EP and ER were analyzed with a direct analysis in real time ionization source coupled to ion trap mass spectrometer. Both of them and SL were analyzed with a Fourier transform infrared spectrometer. The ER was subjected to non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) over Fe-S/ZSM-5, which was formed by in situ reaction of Fe/ZSM-5 with sulfur added, in cyclohexane under pressurized hydrogen at 300°C. The reaction mixtures were sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and IMCDSAMS to afford extracts 1-5 (E1-E5), which were analyzed with a gas chromatography/mass spectrometer (GC/MS). As model reactions, the CHCs of di(1-naphthyl)methane (DNM) and diphenylmethane (DPM) over Fe-S/ZSM-5 were also conducted in cyclohexane at 300°C. The results show that more than 50% of organic matter in the ER was converted to a soluble portion by the CHC, whereas the yield of soluble portion from the NCHC is only 10.52%. GC/MS-detectable species only appear in the E1, which mainly consists of alkanes, arenes, and arenols either from the NCHC or from the CHC. DNM was selectively hydrocracked to naphthalene and 1-methylnaphthalene over Fe-S/ZSM-5, while DPM hydrocracking did not proceed, indicating that Fe-S/ZSM-5 catalyzed the formation of radical hydrogen from molecular hydrogen and subsequent radical hydrogen transfer (RHT) to the ipso-position of naphthalene ring in DNM. Some CH2 and O in the ER could be connected to condensed aromatic rings (CARs). Analogously, RHT to the ipso-position of CARs in the ER resulted in the release of arenes and phenols from the ER. [ABSTRACT FROM AUTHOR]

Highlights: [•] LRMC alkanolysis includes nucleophilic attack, hydrogen transfer and bond cleavage. [•] Reactivities of the LRMCs toward alkanolysis are: BOB>anisole>PEB>ODB. [•] For the same LRMC, ethanolysis proceeds much easier than methanolysis. [Copyright &y& Elsevier]

Highlights: [•] SL was pretreated with H2O2 and then oxidized in NaOCl aqueous solution. [•] The pretreatment significantly increased the yields of soluble species. [•] The pretreatment enhanced the formation of compounds with m/z 300 to 500. [•] The formation of chloro-substituted alkanoic acids was inhibited by the pretreatment. [•] Increase in yields of soluble species is ascribed to introduction of −COOH and −OH. [Copyright &y& Elsevier]

Abstract: Structural features of Shengli lignite (SL) were investigated through ruthenium ion-catalyzed oxidation and oxidations in aqueous hydrogen peroxide (AHPO) and sodium hypochlorite (ASHC) under mild conditions. The results suggest that SL is rich in condensed aromatic species and hydroxyl-, methoxy-, and/or methyl-substituted benzene rings, and –CH2CH2– is a dominant bridged linkage connecting aromatic rings in SL. Aliphatic linkages connecting three aromatic rings also exist in SL. Most of the organic matter in SL was converted into soluble fractions in either AHPO or ASHC. The products from SL oxidation in AHPO are rich in hydroxyl- and/or methoxyl-substituted benzoic acids, alkanoic acids (AAs), and long-chain alkanedioic acids (ADAs), whereas those from SL oxidation in ASHC are mainly composed of benzene carboxylic acids, chloro-substituted short-chain AAs and ADAs. The nitrogen- or sulfur-containing species produced from SL oxidation provide important information on structural features of organic nitrogen and sulfur species in SL. [Copyright &y& Elsevier]

[Display omitted] • Synthetic hollow ZSM-5 (HSZ5) possess higher selectivity for toluene and m/p-xylene. • None-modifier catalysts keep high stability after 7 cycle reactions. • 11HSZ5 exhibits hierarchical meso -microporesity to rich BTEXN at 600 °C. • xHSZ5 show low coke resistance during lignite pyrolysis. Light aromatics could be produced by catalytic fast pyrolysis (CFP) of lignite over HZSM-5 with shape selectivity and accessible active sites. However, the catalytic reactivity in the center crystal has not been fully exploited. In this work, the different hollow hierarchical porosity-tunable ZSM-5 were synthesized using polyethylene glycol as a soft template by a steam-assisted crystallization process. Compared with commercial HZSM-5, the synthesized HZSM-5 exhibited higher selectivity for alkylbenzene (toluene and m/p-xylene) with the yield of 9.91 mg/g (7.31 mg/g over commercial HZSM-5). The hollow HZSM-5 with pore-size fine-tuning were favorable to control the tiny different intermediates for shape-selective of benzene and alkylbenzene in CFP. In addition, the unmodified synthetic hollow catalysts also kept highly stability after seven cycle experiments due to the enhancement of molecules diffusion in crystal center, especially the alkylbenzene yield was sustained at approximately 7.38 mg/g during cycle experiments. The work provides a great prospect to promote the formation of alkyl aromatics in CFP. [ABSTRACT FROM AUTHOR]

• Ga-Sn/AT 0.2 H5 exhibits hierarchical meso-microporesity to rich BTEXN at 600 °C. • Ga and Sn exhibited a strong synergy during the formation of aromatics. • Ga-Sn/AT 0.2 H5 keep high stability after 6 cycle reactions. • Multifunctional catalysts promote the formation of H 2 by dehydrogenation. A multifunctional catalyst of Ga-Sn anchored on hierarchical HZSM‑5 (Sn-Ga/AT 0.2 H5) was investigated in catalytic reforming of lignite pyrolysis volatile. A strong synergy was observed between Ga and Sn for the production of aromatics. The addition of Ga into AT 0.2 H5 remarkably promoted the selectivity of aromatics including benzene, toluene, ethylbenzene, xylene and naphthalene (BTEXN) compared to pure HZSM-5 (H5). The BTEXN yields increased to 24.1 mg/g over monometallic 5%Ga/AT 0.2 H5, in which the benzene yield was attained to 14.8 mg/g. With the introduction of Sn, the yield of aromatics was further improved to 25.1 mg/g. An explanation of this scenario was that introduced active metals could enhance the transformation of cyclic intermediates into aromatics and H5 support with an appropriate concentration of the acid sites provided acidic protons for aromatization. Additionally, the bimetallic Sn-Ga/AT 0.2 H5 exhibited higher stability with the yield of BTEXN maintained over 22 mg/g after three recycle experiments, which offered an efficient strategy to prolong the catalyst lifetime. [ABSTRACT FROM AUTHOR]

• Sulfated HZSM-5 zeolite was prepared by dealumination, realumination and sulfation. • The introduced extra-framework Al affected the textural-acid properties of catalysts. • Sulfation of catalyst after re-introduced extra-framework Al enhanced LAs production. • The highest LAs and lowest coke yield were produced over SO 4 2−/DHZ5-A. Sulfated HZSM-5 zeolite prepared by dealumination, realumination and sulfation was used as the active mesoporous materials to promote the formation of light aromatics during catalytic reforming of volatiles from Shengli lignite pyrolysis. The results show that HCl-dealumination significantly increased the total pore volume (especially mesopores) and average pore size while reducing acid strength and amount of acid sites. The incorporation of the extra-framework Al species to HZSM-5 combined with SO 4 2− to form superacidic surface sulfate complex exhibited an increase in the yield of light aromatics and a decrease in the yield of coke in comparison with that of original HZSM-5. Among the modified catalysts, SO 4 2−/DHZ5-A (introduced the calcined Al 2 O 3 after HCl-dealumination and modified with (NH 4) 2 SO 4) with the acidity enhancement by sulfation obtained the maximum light aromatics yield of 27.3 mg/g and the lowest coke yield of 2.7%. The relationship between the physic-chemical properties of catalysts and the product distribution was proposed to understand the formation of light aromatics. [ABSTRACT FROM AUTHOR]

Fe/attapulgite powder (AP), Ni/AP, and Fe-Ni/AP were prepared by thermally decomposing iron pentacarbonyl (IPC), nickel tetracarbonyl (NTC), and different molar ratios of IPC to NTC onto AP in ethoxyethane, respectively. Their activities for the catalytic hydrocracking of di(1-naphthyl)methane (DNM) were compared under the same conditions. As a result, the activity of Fe-Ni-S/AP (Fe:Ni = 2:1) for DNM hydrocracking is significantly higher than that of other catalysts used. DNM conversion is near 100% over Fe-Ni-S/AP with Fe:Ni = 2:1. Over the catalyst, H 2 can be effectively split to H , which attacks the ipso -position of DNM to cleave the C ar -C alk bridged bond in DNM. Naomaohu lignite was subjected to thermal dissolution/ethanolysis in ethanol to afford soluble portion 1 (SP 1 , yield 56.0%) and residue 1 (R 1) followed by non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) of SP 1 and R 1 at 300 °C using Fe-Ni-S/AP with Fe:Ni = 2:1 as the catalyst to afford SP NCHC , SP CHC , SP 2 (yield 2.3%), and SP II (yield 11.2%). According to gas chromatography/mass spectrometric analysis, arenes are the most abundant in SP CHC , accounting for 21.9%, while the most abundant group component in SP NCHC are non‑nitrogen ketones, accounting for 20.0%. Unlabelled Image • Fe-Ni-S/AP is effective for catalyzing the cleavage of bridged linkages. • More organic matter in R 1 was converted into SP II via CHC procedure. • SP CHC is rich in arenes and arenols, while SP NCHC is dominated by non‑nitrogen ketones. [ABSTRACT FROM AUTHOR]