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We confirmed that reducing the use of a ruthenium catalyst can achieve a similar depolymerization efficiency only by extending the reaction time, and butanone extraction can achieve the separation of inorganic salts and organic components.

A clean and efficient conversion process is essential for the utilization of low-rank coals. Lignite, a typical representative of the low-rank coal family, has huge potential for the production of valuable chemicals via the oxidative depolymerization reaction. Ruthenium ion-catalyzed oxidation (RICO) is an effective route for lignite depolymerization under mild conditions, but the high cost of precious Ru limits the potential large-scale application of RICO. How to recycle and reuse Ru is critical to promote the application of RICO. In this work, a novel and efficient approach for reusing Ru through recycling the solvent mixture containing Ru was established for RICO. First, the influence of different reaction parameters on the depolymerization degree of lignite and benzene polycarboxylic acid (BPCA) yields was investigated. Second, the distribution of Ru in the organic phase (OP), aqueous phase (AP), and residual solid phase (RSP) was analyzed after the RICO reaction. Finally, based on the distribution of Ru in different phases, a novel route of recycling Ru by reusing the Ru-containing solvents was proposed. The results showed that the dosage of RuCl3 and NaIO4 had a significant influence on both the depolymerization degree of lignite and BPCA yields. The distribution of Ru had a close relationship with the depolymerization degree of lignite and the dosage of NaIO4. After the depolymerization reaction, the CCl4 phase containing Ru was reused directly as the solvent for the next run, which could fulfill the reuse of both CCl4 and Ru. The results proved that the Ru-containing CCl4 phase could maintain catalytic performance for 5 runs. This work provides an efficient route to reuse Ru for the RICO depolymerization of lignite into valuable organic acids. As far as we know, this is the first report concerning the recycling and reuse of Ru during the RICO of lignite. This work is important for the application of RICO in lignite depolymerization.

Calcium has been proved to be efficient for the catalytic steam gasification of lignite. In this study, we studied the steam gasification of lignite with Ca(OH)2 added by wet impregnation for to produce hydrogen. The effect of calcium on the microstructural evolution and char gasification behavior in the presence of steam were studied. The distribution of the gaseous products was examined by using fixed-bed micro reactor equipment for steam gasification. Partially gasified chars obtained at different temperatures (400, 500, 600, and 700 °C) in the gasification process were characterized by scanning electron microscopy coupled with energy dispersive spectroscopy, 13C nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and Raman spectroscopy. The results suggested that a “Ca-carboxylate-like structure” was formed due to the addition of calcium to lignite. This Ca-carboxylate-like structure increased the thermal stability of the original carboxylic structure in lignite. As a result, the calcium-added coal retained more oxygen-containing structures, formed more defects, and possessed significantly lower aromatic structures due to the formed Ca-complexes during steam gasification. Therefore, it can be inferred that the Ca-complexes in the lignite char increased the gasification reactivity of char.

Due to the low utilization efficiency of lignite as a primary energy source, the valuable and clean use of lignite becomes important. Oxidative depolymerization of lignite into valuable organic acids (VOAs) has been identified to be feasible, but the difficulty in separating VOAs from the complex lignite depolymerized mixture (LDM) limits the potential application of this route. In this study, based on the coordination interactions between metal ions and carboxylate groups in VOAs, the metal ion-induced separation of VOAs from the LDM was proposed. The results proved that most of the studied metal ions (Mn+) could selectively form M–VOA precipitates with the VOAs in LDM and transferred the VOAs from the water phase into the solid precipitates. Then, the intermediate M–VOAs could be dissolved in diluted NaOH solution to release the VOAs, with Mn+ being transformed into M(OH)n. The separation yield and selectivity could be tuned facilely by various metal ions at different dosages, pH, and temperatures. The process could be fulfilled under near-room temperature in water without the use of organic solvents. Due to its efficiency, tunable selectivity, and green nature, the proposed separation strategy may find potential applications in the valuable and clean use of lignite sources.

Graphite oxide (GO) and graphite (G) were used as Shengli lignite (SL) and char (SL⁺-T) models to study gasification reactivity for the first time. The steam gasification performance of SL⁺, SL⁺-T, G, GO and the corresponding Ca-added samples was evaluated in a fixed bed reactor equipped and linked with a downstream GC system. The samples were comprehensively characterized by Fourier transform infrared, XRD, Raman, X-ray photoelectron spectroscopy, and ¹³C NMR. Results show that calcium exerted a significant catalytic effect on the steam gasification of SL⁺ and GO but had a limited impact on high-temperature char and G. Once the char was oxidized using a similar liquid oxidation method to prepare GO, the steam gasification rate of the oxidized Ca-added char presented higher reactivity at low temperature, which was similar to the gasification behavior of GO with calcium addition. Characterization results show that the oxygen-containing functional group of SL is similar to GO. By comparing the catalytic effect of calcium of oxidized char and GO with that of char and G, it was further demonstrated that the oxygen-containing functional group was the key structure for Ca-catalyzed coal gasification. These results suggest that GO is similar to SL not only in terms of its oxygen structure but also in its steam gasification reactivity. Thus, GO is an excellent model of lignite. This study provides a new lignite modeling approach with a more accurate structure than reported lignite models and is suitable for precise investigations of the structural evolution of lignite as well as the catalytic mechanism of calcium in steam gasification.

The synergistic effects of inherent minerals and specific organic structures in coal on steam gasification were comprehensively investigated herein. The steam gasification of lignite, anthracite, a...

Use of lignite under mild conditions without destroying the natural functional groups and structures is a potential approach for the value-added utilization of lignite. Considering the abundant acidic functional groups in lignite, in this work, a novel and facile route using lignite as robust organic ligands to construct Zr-based catalysts was proposed, and the designed catalysts were applied in the conversion of biomass-derived carbonyl molecules into valuable chemicals. The universality of the proposed route for different rank coals and substrates with various structures were analyzed. Both the preparation conditions of the catalysts and the reaction parameters were systematically investigated. The obtained catalysts were characterized by SEM-EDS, XRD, FTIR, Raman, and TG, etc. The results demonstrated that the designed catalysts were highly efficient for the selective conversion of furfural into furfuryl alcohol. Under the optimized conditions, the conversion, yield, and selectivity were up to 93.4%, 81.0%, and 86.7%, respectively. Both the reaction conditions and the performances of the catalyst were competitive compared with analogous catalysts. It was proved that the catalyst was heterogeneous and the reusability could be improved through demineralization of lignite via acid washing before use, and the catalyst prepared by demineralized lignite had no obvious changes in both performances and structures after 5 reuses. The proposed route was also identified to be applicable for other low rank coals besides lignite, such as long flame coal and coking coal. The catalyst prepared using lignite was robustly effective for the conversion of various carbonyl compounds with different structures, indicating the broad universality for different substrates. Detailed characterization showed that the performances of the catalyst were jointly influenced by both Zr contents and surface areas of the catalyst. This novel route of constructing Zr-based catalysts using low rank coal as raw materials is highly potential for application in the utilization of low rank coals and biomass resources, with the advantages of high efficiency of the catalysts, low cost of raw materials, and simple preparing process.

Carbide slag may pollute the environment because it is difficult to handle. In this paper, carbide slag without pretreatment served as the new source of calcium and was added to bituminous coal for gasification experiments to realize waste utilization. The gasification experiment after adding carbide slag to bituminous coal enhances H2 production, which reduced the activation energy of the gasification reaction. The results show that the catalytic effect on steam gasification was evident when the carbide slag was added to Mongolian bituminous coal. The coal char at reaction temperature was prepared and characterized by X-ray diffraction (XRD), Raman, Scanning electron microscope (SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and FT-IR spectroscopy. The carbon structure evolution and calcium structure changes of coal char under reaction temperature were studied, and the influence of coal char structure changes on gasification performance was analyzed. The results show that in the coal char added with carbide slag, the oxygen-containing functional groups generated by the polycondensation reaction interacted with calcium to form a calcium-oxygen-carbon complex. The existence of this structure not only leads to the highly uniform dispersion of CaO in the char but also hinders the graphitization process of the char. Highly dispersed CaO and disordered carbon structure significantly improved the reactivity of bituminous coal steam gasification. Si and Al in the bituminous coal affected the dispersion of Ca during steam gasification.

CuO–Ni/Al composites were synthesized by electroless deposition and thermal oxidation and characterized by inductively coupled plasma optical emission spectrometry, X-ray powder diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their performances as the heterogeneous catalysts for the solvent-free allylic oxidation of cyclohexene by oxygen were determined. It was found that the CuO contents and the amount of adsorbed oxygen species on the composites could significantly affect their catalytic performances in cyclohexene oxidation. The highest catalytic activity was achieved over CuO–Ni/Al-3 containing 18.5 wt% CuO with the highest amount of adsorbed oxygen species, which resulted in the maximum cyclohexene conversion of 39.1% and the total selectivity of 85.5% to 2-cyclohexene-1-ol, 2-cyclohexene-1-one, 2-cyclohexene-1-hydroperoxide and cyclohexene oxide. In addition, the catalyst was successfully recycled with no significant catalytic activity loss after three cycles.

Hydrogenation of biomass-derived ethyl levulinate (EL) to gamma-valerolactone (GVL) is an important step in the conversion of sustainable biomass resources into value-added chemicals. Exploration of highly efficient and easily obtainable catalysts is crucial for the large-scale application. In this work, a series of cobalt catalysts were prepared by one-step reduction route in different solvents and applied into the conversion of biomass-derived EL to GVL. Common solvents, including water, methanol, ethanol, glycol and glycerin were attempted as the solvent. Both the solvent effect on the catalyst synthesis and the hydrogenation reaction parameters during the conversion of EL into GVL were systematically investigated. The catalysts were characterized by SEM-EDS, TEM, powder XRD, N2 adsorption-desorption, and XPS. The results demonstrated that the solvents had significant influences on the morphology and structure of the as-prepared catalysts, which changed from dendrite (in water) to spheres (in glycerin). All the catalysts prepared in different solvents were effective for the conversion of EL. Under the optimized conditions, a high GVL yield of 91.4% was achieved when using cobalt catalyst prepared in ethanol at relatively mild reaction conditions. Furthermore, the catalyst could be reused at least 6 times without significant loss of the catalytic activity. As far as we know, this is the first work on the application of cobalt catalysts, synthesized by one-step solution phase reduction method, in the conversion of EL into GVL in biomass utilization.

It is important to inhibit the spontaneous combustion of lignite for its safe transportation and efficient utilization. Shengli lignite was treated with a NaOH solution and the as-prepared coal samples were extensively characterized by SEM-EDS, XRD, FT-IR, XPS, and Raman spectra techniques. The combustion properties of NaOH treated lignite were determined by TGA. The results show that NaOH treatment played a significant inhibitory effect on the combustion performance of Shengli lignite. The NaOH treated lignite showed two weight loss temperature regions. The temperature corresponding to the maximum combustion rate of Shengli lignite after the NaOH pretreatment was about 350–400 °C, higher than that of untreated sample, indicating that NaOH treatment significantly decreased the combustion reactivity of Shengli lignite. FT-IR and XPS analyses identified the analogous sodium polycarboxylic acid, originating from the crosslinking combination of carboxyl functional groups with NaOH. It is deduced that the suppressing effect of NaOH treatment on the combustion performance of lignite maybe attributed to the higher stability of analogous sodium polycarboxylic acid.

With the fast depletion of fossil resources, exploring the value-added utilization approaches of low rank coals and promoting the conversion of sustainable biomass resources into useful chemicals are critical topics facing human society. In this work, we attempted low rank lignite as raw materials to construct novel Zr-based catalysts for biomass conversion using the abundant oxygen-containing groups and specific network structures of lignite. Two components of lignite, i.e. humic acids (HA) and the solid residues (SR) after HA extraction, were used to prepare the catalysts. The prepared catalysts were applied into the conversion of biomass-derived ethyl levulinate (EL) to gamma-valerolactone (GVL), an important reaction for the conversion of biomass resources. Both the preparation conditions of the catalysts and the parameters during catalytic reaction process were systematically investigated. The structures of the catalysts were characterized by SEM, TEM, FTIR, powder XRD, and TG analysis. The results demonstrated that the route using lignite as raw materials to construct Zr-based catalysts was feasible, and the designed catalysts were highly efficient for the conversion of EL into GVL. The conversion of EL, GVL yield and selectivity could reach up to >90% under suitable conditions. The catalysts could be used at least 11 recycles without notable changes in both performances and structures, indicating an excellent stability. This work may provide potential ways for both value-added utilization of low rank coals and construction of efficient catalysts for biomass conversion.

Most of the non-noble metal catalysts used for the Meerwein–Ponndorf–Verley (MPV) reaction of carbonyl compounds rely on the additional alkaline additives during preparation to achieve high efficiency. To solve this problem, in this work, we prepared a novel N-doped carbon supported cobalt catalyst (Co@CN), in which the carriers were derived from the nitrogen-rich organic waste, i.e., oxytetracycline fermentation residue (OFR, obtained from oxytetracycline refining workshop). No additional nitrogen sources were used during preparation. The results showed that inherent nitrogen in OFR could provide N-containing basic sites, and formed Co-N structures via coordinating with cobalt. The Co-N sites together with the coexisting Co(0) cooperated to catalyze the conversion of ethyl levulinate (EL) to γ-valerolactone (GVL) by MPV reaction. Co(0) dominated the activation of H in isopropanol, while Co-N dominated the formation of the six-membered ring transition state.

The catalytic effect of calcium on the steam gasification of Shengli chars was studied in this work. The calcium-added chars were prepared by pyrolysis under argon atmosphere from calcium oxide added demineralized Shengli lignite. The chars were characterized in detail by SEM-EDX, XRD, Raman, FTIR and XPS and were tested on a fixed-bed reactor to evaluate its performances steam gasification. Calcium was found to have significantly promotional effect on the steam gasification of char samples with reduces of activation energy. It was observed the presences of 5 wt% or above in the char significantly enhanced H2 productions, which resulted in high H2/CO ratio of syngas. The SEM-EDS and XRD results suggested calcium was highly dispersed within the char particles, CaO and CaS presented in the char samples, but the hydrochloric acid treatment of the char caused significant loss of these calcium compounds. The steam gasification rate of the acid-treated samples was still much higher than that of the no-calcium-added char, which elucidates that superior steam gasification performance of the Ca-added chars was not the simple CaO species in the char, instead, a special calcium lignite intermediate complex “R1-O-Ca-O-R2” (R representing aromatic or aliphatic constituents), formed within char during the pyrolysis. Thus the crosslink-like intermediate complexes “R1-O-Ca-O-R2” structure between calcium and chars was postulated to be the decisive factor to promote the steam gasification of Shengli chars with more production of high hydrogen syngas.

The catalytic effect of sodium on the demineralized Shengli (SL+) lignite char microstructure and the performance of steam gasification were studied. Various sodium compounds including NaNO3, CH3COONa, Na2CO3 and NaOH were loaded on the demineralized coal samples, respectively, and the steam gasification was tested on the fix-bed reactor. The char samples were characterized by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS) and FT-IR spectroscopy. Experimental results showed that sodium hydroxide loaded samples exhibited the highest gasification reactivity among the coal samples prepared. With the increase of the alkalinity of sodium compounds, the carbon crystallite structure tended to be disordered. In the process of pyrolysis, the introduction of sodium species promoted the ring-opening and polycondensation process of the chemicals in the coal samples. The possible reaction mechanism might be inferred that the sodium ions may replace the hydrogen ions in the oxygen-containing functional groups to form sodium phenolate intermediate, which may be critical for the catalytic effect of sodium species during gasification. It was speculated that the ring-opening of the condensation aromatic nucleus was the rate-limiting step in the whole process of gasification.

As the fast depletion of coal resources, exploring the value-added utilization approaches of low rank coals or their components and, in parallel, promoting the conversion of sustainable resources (such as biomass) into useful chemicals are critical issues facing human society. In this work, we used humic acids (HAs), an abundant material in nature (mainly derived from low rank coals), and the transition metal zirconium (Zr) to prepare a novel Zr-containing hydrogen transfer catalyst. The prepared catalyst was applied into the conversion of biomass-derived ethyl levulinate (EL) into gamma-valerolactone (GVL) via hydrogen transfer reaction. Both the preparation conditions of the catalysts and the reaction parameters during the conversion of EL into GVL were systematically investigated. The catalyst was characterized by SEM, TEM, FTIR, powder XRD, and TG analysis. The results demonstrated that the as-prepared catalyst was highly efficient for the conversion of EL into GVL. Under optimized conditions, EL could be completely converted and the GVL yield could reach up to 88.3%. The catalyst could be used at least 11 times without notable changes in both activity and structures, indicating an excellent stability. As far as we know, this is the first work using HAs to prepare Zr-containing catalyst and its application to the conversion of EL into GVL in biomass utilization.

The steam gasification of Shengli (SL) lignite and the demineralized lignite/chars were tested on a laboratory fixed-bed micro reactor system. The evolution rates of syngas, carbon conversions to gas, yields of gaseous products, and H2/CO molar ratios of SL lignite/chars were systematically investigated. Meanwhile, the gasification performance of SL lignite/chars was compared with the corresponding demineralized samples. The results showed that the inherent minerals in SL lignite/chars not only effectively promoted the steam gasification reaction but also considerably improved the gasification selectivity towards the production of H2 and CO2. Further characterizations by the scanning electron microscope (SEM-EDS) and X-ray fluorescence (XRF) demonstrated that it became more difficult for the minerals in SL lignite being eluted by hydrochloric acid solution with the temperature increasing of pyrolysis process. The results confirmed that the inherent minerals and lignite formed metals-lignite intermediate complex during pyrolysis process. The formed metals-lignite intermediate complex works as the active sites which effectively promote the steam gasification performance of SL lignite/chars, especially in favor of the direct generation of high hydrogen syngas.

Construction and application of novel hydrogenation catalysts is important for the conversion of carbonyl or aldehyde compounds into alcohols in the field of biomass utilization. In this work, a novel, efficient, and easily prepared hafnium–graphite oxide (Hf–GO) catalyst was constructed via the coordination between Hf4+ and the carboxylic groups in GO. The catalyst was applied into the hydrogenation of biomass derived carbonyl compounds via the Meerwein–Ponndorf–Verley (MPV) reaction. The catalyst gave high efficiency under mild conditions. An interesting phenomenon was found whereby the activity of the catalyst increased gradually in the initial stage during reaction. The solvent, isopropanol, was proved to have an activation effect on the catalyst, and the activation effect varied with different alcohols and temperatures. Further characterizations showed that isopropanol played the activation effect via replacing the residual solvent (DMF) in micro- and mesopores during the preparation process, which was hard to be completely removed by common drying process.

Research on the structural and combustion properties of coal is of great importance for its conversion and applications in view of fundamental studies. In this work, we conducted the first detailed study on the structural properties and combustion kinetics of Chinese Shenhua raw coal (RC) and its pyrolytic char (PC). The combustion kinetics was simulated by using the random pore model (RPM). The results showed that RC and PC were composed of both a plant-cell-like structure and a discrete particulate structure. In addition, PC had a larger specific surface area, finer particles, higher aromaticity, and higher degree of aromatic ring condensation than those of RC. Combustion of PC showed higher ignition temperature, lower burnout temperature, and a higher combustion index compared to RC. A high correlation coefficient R2 (0.999) and a low average error θ (0.008) were obtained using the RPM. The combustion apparent activation energy E and the structural parameter ψ of RC were 40.30 kJ mol−1 and 0.53, respectively. For PC, the values of E and ψ were estimated to be 60.01 kJ mol−1 and 0, respectively. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

Spontaneous combustion has become a critical limiting factor for the safe and efficient utilization of low rank coals. In this work, the alkali-oxygen oxidation (AOO) of Chinese Shengli lignite was conducted to inhibit the spontaneous combustion tendency, and the influences of AOO on the structures and combustion properties were investigated. The structures of AOO treated lignite under different conditions were characterized by XRD, Raman, XPS and FTIR. The combustion characteristics of the samples were investigated by thermogravimetric analysis and fixed bed combustion. The results revealed that the temperature of AOO treatment had significant influence on the crystallite structures and combustion characteristics of Shengli lignite. After the AOO pretreatment, the benzene ring skeleton structures in lignite had no obvious changes, but the amounts of aliphatic side chains on the aromatic nucleus decreased. Compared with raw lignite, the degree of order and ignition temperature increased after AOO treatment, especially when the AOO temperature was 150–200 °C. The ignition temperatures moved from 310 °C for raw lignite to 740–760 °C for the samples treated by AOO at 150–200 °C. On further increasing the AOO temperatures to 250–300 °C, the ignition temperature of the samples decreased to 410–440 °C. In conclusion, AOO pretreatment under suitable conditions is an efficient way to inhibit the spontaneous combustion tendency of low rank lignite, and it is believed that the results in this work are meaningful for the safe transportation and efficient utilization process of lignite in industry.

With the increasing demands for energy and carbon resources, exploration of novel utilization approaches of fossil resources and promotion of the conversion of sustainable resources become critical issues facing human society. In this study, we used humic acids (HAs), which are important derivatives from the low-rank coal, and the transition metal zirconium (Zr) to construct novel Zr-containing catalysts (Zr-HAs) for Meerwein–Ponndorf–Verley (MPV) reactions of biomass-derived platforms. Both commercial HAs and HAs extracted directly from lignite without any purification were used as raw materials to prepare the catalysts. The results showed that Zr-HAs catalysts were highly efficient for the conversion of furfural, with a high furfuryl alcohol yield of up to 97%, and also effective for the conversion of other carbonyl compounds with different structures under mild conditions. This novel strategy to construct catalysts using HAs as raw materials may be beneficial for both value-added utilization of low-rank coal and the conversion of biomass resources.

Investigation of the effects of demineralization of inherent minerals in Shengli lignite (SL) on its structure and combustion property in the field of coal conversion is an extremely important and interesting topic. In this study, inherent minerals in SL were demineralized by hydrochloric acid (HCl) treatment. Further, the metals cations Na + , Al 3+ , K + , Ca 2+ , Mn 2+ and Fe 3+ , corresponding to the inherent metal ions in lignite were added into the demineralized samples by the impregnation method in order to compare their effects. The surface morphology and structure parameters of the raw and demineralized lignite samples were characterized by SEM, nitrogen adsorption–desorption, FTIR, XPS, XRD and Raman spectroscopy. The combustion properties of lignite samples were investigated by thermogravimetric analysis. Demineralization led to an improvement in the amount of side chains in SL and destroyed the pore structure and aromaticity; however, it did not have obvious effects on the surface morphology of SL and the main forms of carbon and oxygen. Moreover, demineralization increased the ignition temperature and apparent activation energy, and decreased the combustion stability index of SL. Added aluminum ions resulted in a decrease in the combustion stability and reactivity of the HCl treated sample; however, the added metals cations such as Na + , K + , Ca 2+ , Mn 2+ and Fe 3+ , exhibited opposite effects.

Conversion of biomass into 2,5-dimethyltetrahydrofuran (DMTHF), an excellent fuel additive, solvent, and industrial intermediate, is an important reaction in green chemistry. In this work, different combinations of supported metal catalysts and solid acids were investigated for the synthesis of DMTHF from biomass derived diketone (2,5-hexanedione, 2,5-HD). The results showed that commercial Pt/C and solid acid Amberlite®IR-120H had an excellent cooperative effect on the reaction. 2,5-HD could be converted into DMTHF with a yield up to 99% under milder conditions. Further experiments indicated that 2,5-hexanediol (2,5-HDO) is a key intermediate in the reaction. The catalyst system could be facilely recovered due to the heterogeneity and reused several times without notable change in the performance.

This work reports the utilization of hydrogen in water for the hydrogenation of organic compounds and the oxygen for the oxidation of glucose simultaneously by photocatalysis., Direct utilization of the abundant hydrogen and oxygen in water for organic reactions is very attractive and challenging in chemistry. Herein, we report the first work on the utilization of the hydrogen in water for the hydrogenation of various organic compounds to form valuable chemicals and the oxygen for the oxidation of glucose, simultaneously by photocatalysis. It was discovered that various unsaturated compounds could be efficiently hydrogenated with high conversion and selectivity by the hydrogen from water splitting and glucose reforming over Pd/TiO2 under UV irradiation (350 nm). At the same time, glucose was oxidated by the hydroxyl radicals from water splitting and the holes caused by UV irradiation to form biomass-derived chemicals, such as arabinose, erythrose, formic acid, and hydroxyacetic acid. Thus, the hydrogen and oxygen were used ideally. This work presents a new and sustainable strategy for hydrogenation and biomass conversion by using the hydrogen and oxygen in water.

Conversion of cellulose into value-added chemicals and/or fuels has attracted worldwide attention due to the dwindling fossil fuel reserves and concerns over global warming. Herein, the conversion of microcrystalline cellulose into oxalic acid in homogeneous NaOH solution catalyzed by metal oxides under low oxygen pressure was reported. The effects of metal oxides, reaction temperature, reaction time, and oxygen pressure on the yields of the major products were studied. The results showed that a high yield of organic acids, mainly including oxalic acid, formic acid, glycolic acid, lactic acid, and acetic acid, could be obtained. Catalytic amounts of CuO could effectively improve the yield of oxalic acid. The yield of the oxalic acid could be as high as 41.5% with catalytic amount of CuO at oxygen pressure of 0.3 MPa and 200 °C for 2 h. A tentative reaction pathway for the selective oxidation of cellulose into small molecular organic acids in aqueous NaOH solution was investigated and proposed.

The effect of water on CO2 hydrogenation to produce higher alcohols (C-2-C-4) was studied. Pt/Co3O4, which had not been used previously for this reaction, was applied as the heterogeneous catalyst. It was found that water and the catalyst had an excellent synergistic effect for promoting the reaction. High selectivity of C-2-C-4 alcohols could be achieved at 140 degrees C (especially with DMI (1,3-dimethyl-2imidazolidinone) as co-solvent), which is a much lower temperature than reported previously. The catalyst could be reused at least five times without reducing the activity and selectivity. D2O and (CH3OH)-C-13 labeling experiments indicated that water involved in the reaction and promoted the reaction kinetically, and ethanol was formed via CH3OH as an intermediate.

A novel Heck reaction catalyst consisting of a palladium(II) complex of meso-tetra(p-hydroxyphenyl)porphyrin (MTP) and cross-linked chloromethylated polystyrene microspheres (PMs) was successfully prepared via covalent ether bonds between the chloride groups in the PMs and the hydroxyl groups in MTP. The catalyst was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES). This polystyrene-supported palladium-complex was an efficient heterogeneous catalyst for cross-coupling of aryl iodides with ethyl acrylate. The reaction of iodobenzene and ethyl acrylate under N-2 at 100 degrees C and a catalyst concentration of 0.1% gave a gas chromatography product yield of 99.8%, which is much higher than that achieved using a free palladium(II) complex of MTP as the catalyst (41.3%). The catalyst was recycled up to six times without significant loss of catalytic activity. These results suggest that the immobilized palladium(II)-MTP catalyst has potential applications in synthetic and industrial chemistry. (C) 2014 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Transformation of anisole (methoxybenzene), a typical component of bio-oil, into phenol and methylated phenols was studied over HY zeolites with framework Si/Al ratios of 5, 15, 25, and 35. It was demonstrated that the amounts of BrOnsted acid and Lewis acid sites, the ratio of Lewis acid and BrOnsted acid sites, and the textural properties of the zeolites were all crucial parameters that influenced the catalytic performance. The BrOnsted acid and Lewis acid sites of the zeolites catalyzed the reaction cooperatively and efficiently promoted the transmethylation. The hierarchical channel system with fully open micropore-mesopore connectivity was favorable to reduce the amount of coke generated.

The acid catalytic conversion of carbohydrates into levulinate esters followed by metal catalytic hydrogenation is an important approach to obtain gamma-valerolactone (GVL) from biomass. In this work, we prepared the highly cross-linked polymer of divinylbenzene with acid ionic liquid (PDVB-IL) and supported Co on TiO2 (Co/TiO2), which were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and elemental analysis. It was demonstrated that the PDVB-IL polymer could efficiently catalyze the esterification reaction of furfuryl alcohol (FAL), 5-hydroxymethylfurfural (HMF), and fructose with ethanol to produce the intermediate ethyl levulinate (EL), and the EL in the reaction mixture was directly hydrogenated to GVL over the Co/TiO2 without requiring purification and with high yields.

Production of value-added chemicals using carbon dioxide (CO2) as a feedstock is favorable to the sustainable development of the chemical industry. In this work, we have discovered for the first time that CO2 can react with propargylic amines to produce 3,4,5-trisubstituted oxazolones, a class of very useful chemicals. It was found that the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) can catalyze the reactions efficiently at atmospheric pressure under metal-free conditions. It was also found that [Bmim][OAc] and IL 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([Bmim][Tf2N]) have an excellent synergistic effect for promoting the reactions. The [Bmim][OAc]/[Bmim][Tf2N] catalytic system can be reused at least five times without loss in catalytic activity and selectivity. The reaction mechanism was proposed on the basis of density functional theory (DFT) calculation and the experimental results.

Ionic liquid 1-benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BnMIm][NTf2]) can promote the generation of the ˙OOH free radical and thereby efficiently transformed the β-O-4 lignin model compound 2-phenoxyacetophenone into benzoic acid and phenol using O2 as the oxidant. Furthermore, the IL-based metal-free catalytic system can also depolymerize other lignin model compounds and organosolv lignin effectively.

Catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) to γ-valerolactone (GVL) is a very attractive reaction in the field of biomass transformation. In this work, a new porous Zr-containing catalyst with a phenate group in its structure was prepared by the coprecipitation of 4-hydroxybenzoic acid dipotassium salt and ZrOCl2 (Zr-HBA) in water and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption, and Fourier transform infrared spectroscopy. The Zr-HBA was used as the catalyst for CTH of EL to GVL in the presence of isopropanol, and the effects of temperature, time, and the amount of the catalyst on the reaction were studied. It was found that Zr-HBA was very active for the reaction and a GVL yield of 94.4% could be achieved. Meanwhile, the Zr-HBA could be reused at least five times without a notable decrease in activity and selectivity. The main reason for the high catalytic activity of the Zr-HBA was that the existence of a phenate in the structure of Zr-HBA increased the basicity of the catalyst, which is favourable for the CTH of EL.

Both effective utilization of glycerol and reduction of nitrobenzene to aniline are of great importance. It is very interesting to integrate these processes. This work reports the integration of the efficient conversion of nitrobenzene to aniline and transformation of glycerol to valuable chemicals driven by UV-light using Pd/TiO2 as the catalyst and water as the solvent at ambient temperature. In this integrated reaction process, glycerol acted as the hydrogen source for the reduction of nitrobenzene to aniline and the glycerol was converted into value-added chemicals simultaneously. At the optimized conditions, nitrobenzene could be converted completely with aniline selectivity of 95% with a nitrobenzene to glycerol mole ratio of 1 : 5. At the same time, glycerol was oxidized to form fine chemicals, including 1,3-dihydroxyacetone, glyceraldehyde, formic acid, and hydroxyacetic acid. This work opens up a new and effective way for transformation of glycerol to fine chemicals and production of aniline from nitrobenzene.

An efficient bifunctional NbOPO4 supported Ru catalyst (Ru-NbOPO4) was applied to the hydrodeoxygenation of aromatic ethers and phenols and the upgrading of bio-oil. Characterization results revealed that the Ru-NbOPO4 catalyst possessed strong acidity, including Lewis and Bronsted acids. The Lewis acid sites originated from the Nb O bonding structures, including slightly distorted octahedral NbO6, regular tetrahedral NbO4 and highly distorted octahedral NbO6. In combination with the strong acidity of the Nb O species and excellent hydrogenation activity of the metallic Ru, the bifunctional Ru-NbOPO4 catalyst exhibited an excellent catalytic activity in the hydrodeoxygenation of aromatic ethers and phenols with different structures, and even real bio-oil to alkanes. The hydrocarbon yield after real bio-oil upgradation was up to 88.2 %. Carbon deposition and enlargement of the Ru nanoparticles resulted in slight deactivation of the catalyst. The catalytic activity could be mostly recovered after being calcined and reduced.

Developing efficient and clean utilizing route of low-ranked lignite is a highly desirable and significant topic in view of value-added utilization of coal resources. Depolymerizing lignite into water-soluble fractions is a promising route for lignite utilization, but how to use the depolymerized mixtures efficiently becomes a critical issue for promoting the application of this route. In this study, the raw lignite was depolymerized by alkali-oxygen oxidation, and the water-soluble alkali-oxygen oxidation products (AOOPs) were directly used without tedious purification to construct novel Cu-AOOPs catalysts for aerobic oxidation of alcohols into aldehydes. Both the preparation conditions of the catalysts and the reaction parameters during the catalytic reaction were systematically studied. The structures of the catalysts were characterized in detail by SEM, TEM, Power XRD, FT-IR, XPS, TG, ICP-OES and BET. The results showed that the proposed route was feasible to prepare Cu-AOOPs catalysts for alcohol oxidation using depolymerized mixtures from lignite. The obtained Cu-AOOPs catalysts were highly efficient for the selective oxidation of benzyl alcohol, and both the conversion of benzyl alcohol and the yield of benzaldehyde could reach up to 90% under mild temperature (

CaCO3, Ca(CH3COO)2 and Ca(C6H5COO)2 were selected as representatives of calcium species formed by calcium ions with organic structures and added to an acid-leached Shengli lignite (SL+) to study the catalytic mechanism of calcium on the steam gasification. The main gasification temperature range of the calcium-added samples was surprisingly consistent with the specific thermal decomposition temperature of the added calcium compounds. XPS and FTIR revealed that the added calcium interacted strongly with the oxygen-containing functional groups in lignite to form calcium-carboxylate, which were further converted to CaCO3 analogous structure during the thermal process (confirmed by XRD). The significant catalytic effect of calcium on the steam gasification all occurred simultaneously with the decomposition of CaCO3 analogous. The formed calcium species from the decomposition of in-situ formed CaCO3 could interact with the adjacent carbonaceous organic structures in lignite under the presence of gaseous water molecules to form calcium-centered complexes. The calcium-catalyzed effects on the steam gasification were depended on the decomposition processes of in-situ formed CaCO3 species. Finally, the possible mechanism for the catalytic effect of calcium on the steam gasification of Shengli lignite was proposed.