Fang-Jing Liu

Nitrogen-doped porous carbon foams prepared from mesophase pitch through graphitic carbon nitride nanosheet templates

A scalable and facile method was developed to synthesize nitrogen-doped porous carbon foams (NDPCFs) using graphitic carbon nitride (g-C3N4) nanosheets as hard templates through the calcination of mesophase pitch. The morphology, structure, chemical composition and electrochemical performance of the as-prepared NDPCFs were characterized and investigated. The results show that NDPCFs are fabricated from crimpled and folded carbon nanosheets and have a three-dimensional interconnected structure. The carbon nanosheets show a certain degree of orientation of graphite crystallites. The specific surface area, wall thickness and nitrogen content are controllable by tuning the mass ratio of g-C3N4 nanosheets to mesophase pitch. The content of nitrogen species, most of which are quaternary-N and pyridinic-N components, significantly decreases from 6.48 to 0.74 at% with raising calcination temperature from 800 to 1600 °C. The NDPCFs prepared at 800 °C have a high specific surface area of 2098 m2 g−1, an ultra-large pore volume of 5.048 cm3 g−1 and a high nitrogen content of 6.48 at%. Furthermore, this material exhibits remarkable electrochemical performance as an electrode material for supercapacitors with a specific capacitance of 125.6 F g−1 even at a high scan rate of 200 mV s−1.

Analysis of the Products from the Oxidation of Geting Bituminous Coal by Atmospheric Pressure Photoionization–Mass Spectrometry

Geting bituminous coal was directly oxidized in aqueous sodium hypochlorite. The reaction mixture was sequentially extracted with ethyl ether and ethyl acetate. Both extracts were esterified with diazomethane to obtain methyl esterified products, which were analyzed using high performance liquid chromatography–mass spectrometry with electrospray ionization or atmospheric pressure photoionization. A large number of low- and nonpolar products with relatively high molecular masses were determined using atmospheric pressure photoionization mass spectrometry. Toluene and a toluene/anisole mixture (vol/vol = 95:5) were added to the atmospheric pressure photoionization system as dopants. Toluene induced better ionization than the toluene/anisole mixture in both ion signal intensity and number of detected species. Most of the molecular associated compounds contained heteroatoms.

Mild oxidation of Jincheng NO. 15 anthracite

Abstract Jincheng NO. 15 anthracite (J15A) was subjected to ruthenium ion-catalyzed oxidation to characterize its structural feature. The results show that J15A is abundant in peri -condensed aromatic structure. The NaOCl oxidation of J15A promoted by pretreatment with H 2 O 2 was conducted under mild conditions to produce benzene polycarboxylic acids (BPCAs). The pretreatment with H 2 O 2 is proved to enhance the yields of BPCAs. It is potential to obtain BPCAs in high yield and selectivity by NaOCl oxidation of pretreated J15A with H 2 O 2 .

Evaluation of an Upgraded Bio-oil from the Pyrolysis of Rice Husk by Acidic Resin-catalyzed Esterification

A raw bio-oil (RBO) from pyrolysis of rice husk was upgraded by catalytic esterification with methanol over an acidic resin. Both RBO and the upgraded bio-oil (UBO) were analyzed with a Fourier transform infrared spectrometer, pH meter, and an elemental analyzer. They were extracted sequentially with n-hexane, CCl4, CS2, benzene, and CH2Cl2. All of the extracts were analyzed with gas chromatography/mass spectrometer. The results showed that the carboxylic acids (CA) in the RBO were converted to their corresponding methyl esters (MEs), leading to a significant increase in pH value from 2.8 (RBO) to 5.3 (UBO). The total extract yield of UBO is much higher than that of RBO. In total, 20 CAs and 19 MEs were identified. The CAs include two alkenoic acids, a cycloalkanecarboxylic acid, a hydroxyalkanoic acid, a hydroxyalkenoic acid, an oxyalkanoic acid, a methoxyoxyalkanoic acid, an alkanedioic acid, an oxyalkanedioic acid, an aminoalkanoic acid, two furoic acids, three substituted benzoic acids, and five substituted phenylalkanoic acids.

The Effect of Pretreatment with H2O2 on the Oxidation of Shenfu Subbituminous Coal with NaOCl

Shenfu subbituminous coal (SFSBC) and pretreated SFSBC with H2O2 were subjected to oxidation with NaOCl at 30°C for 5 h. The results show that the pretreatment with H2O2 significantly increased the yields of water-soluble species (WSS), especially benzene carboxylic acids (BCA) and long-chain alkanedioic acids (LCADA), but substantially inhibited the formation of chloro-substituted alkanoic acids. The introduction of oxygen functional groups to SFSBC by the pretreatment (LCADA) could be responsible for the increase in the yields of WSS, especially BCA and LCADA.

Rapid analysis of carboxylic acids and esters with a direct analysis in real time ion source

RATIONALE Coal oxidation produces carboxylic acids (CAs), including aliphatic acids, benzoic acids, and benzenepolycarboxylic acids, which are important fine chemicals and could be used for understanding the structural features of coals. However, detecting CAs usually faces great challenges due to extremely troublesome pretreatments. Therefore, it is essential to develop an analytical method for rapidly detecting CAs from coal oxidation. METHODS A series of model compounds (MCs) of oxidation products and 2 practical samples were investigated by direct analysis in real time/time-of-flight mass spectrometer (DART/TOF-MS) under 3 different analytical conditions (ionizing gas temperature, organic solvent, and MC concentration). RESULTS Ionizing methyl benzoate, dimethyl phthalate, and dimethyl adipate produces typical ions of methyl esters, including [M - OCH3 ]+ , [M + H]+ , and [M + NH4 ]+ . In contrast, the characteristic ions generated from CAs are polymer ions, such as [2M + NH4 ]+ , [3M + NH4 ]+ , [4M + NH4 ]+ , and [5M + NH4 ]+ , indicating the strong intermolecular hydrogen-bond interaction among CAs. CONCLUSIONS Results suggest that DART/TOF-MS could rapidly analyze CAs or esters in coal oxidation products according to their typical ions for further facilitating deep insight into the coal structure.

Anthracene Oxidation in an Aqueous SodiumHypochlorite Solution

Anthracene was used as a model compound for condensed aromatics in coals and liquid fuels. Its oxidation in aqueous sodium hypochlorite solution at 30°C, 40°C and 50°C was investigated, respectively. The results from gas chromatography/ mass spectrometry analysis show that anthracene can be converted to 22 products completely within 48 h. Non-chloro-substituted compounds are the main products and their total yield is much higher than that of chloro-substituted compounds, especially in the reaction for 96 h. Anthraquinone is the most abundant product and its yield reached maximum in the oxidation for 96 h at 40°C. The mechanisms for anthracene oxidation and chlorination are discussed.

Difference in Molecular Composition of the Carbon Disulfide/Acetone-extractable Fraction between Xilinhaote Lignite and Geting Bituminous Coal

Xilihaote lignite (XL) and Geting bituminous coal (GBC) were extracted using isometric carbon disulfide/acetone binary solvent at 45°C under microwave irradiation. The raw coals and residues were analyzed with a Fourier transform infrared spectrometer and the extracts with a gas chromatograph/mass spectrometer. The results show that the extract yield of GBC is much higher than that of XL lignite and the molecular composition of the extract from XL is significantly different of that from GBC.