APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Xiaoqian Guo,Feng Guo,Yishan Li,Zhangqin Zheng,Zhexu Xing,Zihan Zhu,Ting Liu,Xin Zhang,Ying Jin
Dehydration of D-xylose to yield furfural was carried out using bimetallic salts of a heteropolyacid as the catalyst at 160–220 °C in the DMSO/H 2 O mixtures. The effect of Sn/Cs molar ratio of the bimetallic salts of 12-tungstophosphoric acid (PW) obtained by ultrasound-assisted coprecipitation on dehydration of D-xylose was investigated. The resultant catalysts were characterized by X-ray diffraction, N 2 adsorption, field emission scanning electron microscopy and energy dispersive X-ray (EDX). It was found that the Sn-Cs codoped PW catalysts retained the Keggin crystal structure of PW. Sn 0.625 Cs 0.5 PW was the most active catalyst in the dehydration of D-xylose into furfural. The maximum D-xylose conversion (close to 100 wt %) and furfural yield (63 wt %) were achieved at 200 °C for 3 h in DMSO/H 2 O mixtures. It was found that 16.7 wt % Sn 0.625 Cs 0.5 PW on a chitosan-derived support displayed similar catalytic activity to that of Sn 0.625 Cs 0.5 PW and good stability after recycling six times.
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高影响因子
ChemSusChem
·
2013
·Vol. 6
·期 5
·820-825
·
IF 7.475
Qingbin Wu,Yani Yan,Qian Zhang,Jinhua Lu,Zhijian Yang,Yahong Zhang,Yi Tang
Graphical Between the sheets: A simple and efficient microwave-assisted HNb 3 O 8 catalytic process is proposed for the dehydration of carbohydrates in a sustainable pure aqueous system, in which the fast in situ exfoliation of the layered HNb 3 O 8 under microwave irradiation is crucial for the remarkable catalytic performance. A simple and efficient microwave-assisted HNb 3 O 8 catalytic process is proposed for the dehydration of carbohydrates in the aqueous phase. A 5-hydroxymethylfurfural (HMF) yield of 55.9 % was achieved at a high substrate/catalyst weight ratio of 50 from a 10 wt % fructose solution, which is close to the yield achieved by homogeneous aqueous systems. The critical factor for this performance is the fast in situ exfoliation of layered HNb 3 O 8 with the aid of microwave irradiation, which leads to quasi-homogeneous catalytic behavior. Importantly, the catalytic system is also applicable for the one-pot production of HMF from di- and polysaccharides, such as inulin, through a consecutive hydrolysis–dehydration reaction. Additionally, the unique restacking feature of the exfoliated HNb 3 O 8 ensures the good reusability of the catalyst.
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高影响因子
RSC Advances
·
2013
·Vol. 3
·期 20
·7360-7366
·
IF 2.562
Shimin Kang,Jun Ye,Yu Zhang,Jie Chang
Amorphous carbon-based sulfonated catalysts were generated from four kinds of biomass (lignin, cellulose, wood meal and D-xylose) by hydrothermal carbonization at various temperatures (225, 245 and 265 °C) followed by sulfonation, with a yield of 36–56%. All of these catalysts showed aromatic structure, hydroxyl and carboxyl groups, with a density of SO3H groups between 0.56 and 0.87 mmol g−1. 5-Hydroxymethylfurfural (HMF) was produced from inulin in ionic liquids (ILs) in one step with the addition of carbon-based sulfonated catalysts, with a factual yield of 47–65% at 100 °C, 60 min. Moderate extension of reaction time (from 30 to 90 min) and increase of temperature (from 80 to 120 °C) promoted HMF production. Ethyl acetate was used as extractant, and about 39–55% of HMF can be recovered from ILs. One problem with these carbon-based sulfonated catalysts was that they would be partly deactivated in ILs for separate reuse, however, they can be easily regenerated by dilute sulfuric acid treatment. The carbon-based sulfonated catalysts exhibited good catalytic activity compared with traditional solid acid catalysts, and the carbon-based sulfonated catalyst/ILs reaction system showed high reusability. In consideration of the renewable as well as the high catalytic activity abilities, these biomass derived carbon-based sulfonated catalysts would be promising for industrial application.
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高影响因子
ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Guiju Xu,Shengju Liu,Jiaxi Peng,Wenping Lv,Ren’an Wu
In this work, a novel core–shell structured gold@graphitized mesoporous silica nanocomposite (Au@GMSN) was synthesized by in situ graphitization of template within the mesochannels of mesoporous silica shell on gold core and demonstrated to be promising nanomaterials for surface-assisted laser desorption/ionization time-of-flight mass spectroscopy (SALDI-TOF MS). The integration of the graphitized mesoporous silica with the gold nanoparticles endowed Au@GMSN with large surface areas of graphitic structure, good dispersibility, and strong ultraviolet (UV) absorption. Au@GMSN exerted the synergistic effect on the efficient detection of small-molecular-weight analytes including amino acids, neutral saccharides, peptides, and traditional Chinese medicine. The Au@GMSN-assisted laser desorption/ionization exhibited the following superiorities: high ionization efficiency, low fragmentation interference, favorable salt tolerance, and good reproducibility. Moreover, because of the large hydrophobic inner surface area of the graphitized mesoporous silica shell, the Au@GMSN demonstrated its promising capacity in the pre-enrichment of aromatic analytes prior to SALDI-TOF MS, which favored rapid and sensitive detection.
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 74
·39453-39462
·
IF 3.708
Yani Yan,Qingbin Wu,Xiao Guo,Jinhua Lu,Zhen Hua Li,Yahong Zhang,Yi Tang
The highly selective isomerization and dehydration of various carbohydrates (glucose, xylose, cellobiose and cellulose) are one-pot conversions conducted in a simple borate-containing phosphate buffer solution (PBS) under microwave irradiation. It is demonstrated that the key to glucose converting into 5-hydromethylfurfural (5-HMF) with a high selectivity is matching the isomerization and dehydration processes of glucose at the appropriate boron/glucose mole ratio (B/G) and pH of PBS with the aid of microwave irradiation. Moreover, the interaction between borate and glucose in the isomerization process has been demonstrated by both Raman spectra and theoretical calculations. Furthermore, the reusability of such a PBS system with borate has been accomplished by the successive addition of glucose and by the continual removal of 5-HMF in a biphasic system. These results not only deepen the understanding of the isomerization and dehydration behavior of glucose, but also provide the possibility for practical applications, owing to the appealing green, inexpensive and sustainable characteristics of such a catalytic system.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2015
·
IF 4.494
Zhiping Xu,Wenzhi Li,Zhijie Du,Hao Wu,Hasan Jameel,Hou-min Chang,Longlong Ma
A novel solid acid catalyst was prepared by the copolymerization of p-toluenesulfonic acid and paraformaldehyde and then characterized by FT-IR, TG/DTG, HRTEM and N 2 -BET. Furfural was successfully produced by the dehydration of xylose and xylan using the novel catalyst in γ-valerolactone. This investigation focused on effects of various reaction conditions including solvent, acid catalyst, reaction temperature, residence time, water concentration, xylose loading and catalyst dosage on the dehydration of xylose to furfural. It was found that the solid catalyst displayed extremely high activity for furfural production. 80.4% furfural yield with 98.8% xylose conversion was achieved at 170 °C for 10 min. The catalyst could be recycled at least five times without significant loss of activity. Furthermore, 83.5% furfural yield and 19.5% HMF yield were obtained from raw corn stalk under more severe conditions (190 °C for 100 min).
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 66
·34944-34949
·
IF 3.708
Jintao Lin,Shuangyue Li,Mingzhong Sun,Cuili Zhang,Wenbo Yang,Zehui Zhang,Xiaojie Li,Shao Li
The economical production of biodiesel from lignocellulose hydrolysates requires a robust D-xylose fermentation path. The present work found that Lipomyces starkeyi AS 2.1560 and Rhodosporidium toruloides AS 2.1389 could produce micro-lipid effectively from D-xylose solution by a two-stage culture mode. Results demonstrated that both L. starkeyi and R. toruloides could achieve high lipid production in xylose solution. High cell density fermentation was carried out by a feed-batch fermentation mode. After fermentation for 48 h in a bioreactor using unsterile xylose solution by L. starkeyi, the biomass, lipid and lipid content reached 97.4 g L−1, 63.9 g L−1, and 65.5%, respectively. Accordingly, the lipid productivity reached 1.3 g L−1 h−1 in the second stage. And the overall lipid productivity was 0.55 g L−1 h−1. Therefore, L. starkeyi and R. toruloides are highly effective D-xylose-fermenting oleaginous yeasts for lipid production in xylose solution. The two-stage culture method should provide a new opportunity to make the industrial production of biodiesel possible in the future.
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RSC Advances
·
2014
·Vol. 4
·期 69
·36603-36614
·
IF 3.708
Hongyun Peng,Lingling Gao,Mengjiao Li,Yibin Shen,Qiongqiu Qian,Xia Li
Bio H2 conversion from wetland lignocellulosic biomass is one of the promising alternatives to fossil fuels. Both Phragmites (sp.) and Thalia dealbata are holocellulose-rich and lignin-rich wetland plant biomasses. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) demonstrated alteration of lignocellulosic structures due to hemicelluloses removal by steam explosion (SE) pretreatment, and further disruption of cellulose crystallinity after treatment with SE followed by [Bmim]Cl (SE-[Bmim]Cl). Thermogravimetry/differential thermogravimetry (TG/DTG) revealed an increase in amorphous cellulose and partial delignification in lignocellulosic structures as a consequence of SE-[Bmim]Cl. The pretreatment of both SE and SE-[Bmim]Cl yielded lignocellulosic substrates with improved properties in terms of their conversion into glucose and bio H2. Five-to-ten folds (by SE) and ten-to-twenty folds (by SE-[Bmim]Cl) more glucose was released from the lignocellulosic substrates of both plants than those of contrast samples. Compared to Phragmites (sp.), the greater destruction in lignocellulosic structure of Thalia dealbata as a result of SE and SE-[Bmim]Cl, increased the accessible surface area and disrupted the cellulose crystallinity much more, thus making it more efficient for bio H2 conversion. The bio H2 of 1.97 ± 0.14 mmol H2 g−1 dry weight (DW) was yielded after sludge anaerobic fermentation of Thalia dealbata treated with SE, and it increased to 4.79 ± 0.86 mmol H2 g−1 DW after SE-[Bmim]Cl treatment. For Phragmites (sp.) it was 1.45 ± 0.42 and 2.75 ± 0.76 mmol H2 g−1 DW after SE and SE-[Bmim]Cl pretreatment, respectively. Therefore, SE-[Bmim]Cl pretreatment can be developed for efficiently enhancing bio H2 conversion from wetland plant Thalia dealbata.
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JOURNAL OF MEMBRANE SCIENCE
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2016
·
IF 5.557
Hang Lyu,Yan Fang,Shuang Ren,Kaifei Chen,Gang Luo,Shicheng Zhang,Jianmin Chen
Through hydrothermal liquefaction (HTL), lignocellulosic biomass is directly hydrolyzed into small organics like monosaccharides, monophenols and acids, which can be used as valuable chemicals by further purification. This study aims at investigating the feasibility of simultaneous separation of monophenols from sugar and acids in model lignocellulosic hydrolysate solution through two-stage nanofiltration (NF) and reverse osmosis (RO) process. The effects of pressure, temperature and pH on the solute retentions and permeate flux were examined with an eight-solute sugar-monophenols-acids model solution. NF-RO (DK-SE) two-stage membrane process was performed to confirm the multistage separation performance of model hydrolysates under an optimal operation condition. Results showed that membranes with higher water permeability had better performance in separation of sugar from monophenols. The decrease in temperature promoted separation of both acetic acid and monophenols from sugar, while higher pressure and lower temperature favored separation of acetic acid from phenols . The pH should be kept at low values to maintain good monophenols simultaneous separation of from sugar and acids. The maximum separation factors of acetic acid over 2,6-dimethoxyphenol and 2,6-dimethoxyphenol over glucose were 99.59 by RO membrane SE and 29.99 by NF membrane DK, respectively. Two-stage membrane process (DK NF+SE RO) was proven to be a feasible way to fractionate model HTL hydrolysates into three parts: incomplete hydrolyzed biomass fragments, monophenols riched concentrate, and acetic acid permeate.
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ACS Sustainable Chemistry & Engineering
·
2016
·
IF 5.267
Xing-kang Li,Zhen Fang,Jia Luo,Tong-chao Su
In order to develop a process for the simultaneous production of furfural and easily hydrolyzable cellulose, the degradation of sugar cane bagasse in a single aqueous system and in a 2-methyltetrahydrofuran (MTHF)/aqueous AlCl3 biphasic system was studied. In single aqueous system, the influence of acid species (FeCl3, HCl, and AlCl3) on furfural production and cellulose degradation was investigated at 150 °C. FeCl3 and HCl promoted furfural production from hemicellulose but with severe cellulose degradation. AlCl3 decreased cellulose degradation with considerable furfural yield and high glucan content in solid residues. The role of NaCl in furfural production and cellulose decomposition was also investigated in the single aqueous system using different acids as catalysts. Addition of NaCl significantly promoted furfural yield but also accelerated cellulose decomposition when FeCl3 or HCl was used as catalyst. In the AlCl3-catalyzed system, NaCl had less influence on residue yield and its composition, although NaCl also promoted furfural production. The influence of MTHF on furfural yield, residue composition, and enzymatic hydrolysis of residue was also studied. Under the best conditions (0.45 g of bagasse, 9 mL of MTHF, 9 mL of water, 0.1 M AlCl3, 150 °C, 45 min, and 10 wt % NaCl), 58.6% furfural was obtained while more than 90% of cellulose remained in the residue. The organic phase was separated from the aqueous phase directly by decantation. After reuse of organic phase for 3 cycles, 11.5 g/L furfural was obtained. The catalyst-containing aqueous phase could be reused directly after decantation of the organic phase without loss of activity. The obtained residue was easy to hydrolyze and produced 89.3% glucose yield after 96-h enzymatic hydrolysis at low cellulase loading (30 FPU of cellulase/g glucan).
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PREPARATIVE BIOCHEMISTRY & BIOTECHNOLOGY
·
2016
·
IF 1.114
Xue-Fang Chen,Chao Huang,Lian Xiong,Bo Wang,Gao-Xiang Qi,Xiao-Qing Lin,Can Wang,Xin-De Chen
Elephant grass (Pennisetum purpureum) dilute acid hydrolysate contains 34.6 g/L total sugars. The potential of lipid production by oleaginous yeast Trichosporon cutaneum grown on elephant grass acid hydrolysate was investigated for the first time. During the fermentation process on the elephant grass acid hydrolysate, glucose, xylose, and arabinose could be well utilized as carbon sources by T. cutaneum. Interestingly, xylose was almost no use before glucose was consumed completely. This illustrated that simultaneous saccharification of xylose and glucose by T. cutaneum did not occur on elephant grass acid hydrolysate. The highest biomass, lipid content, lipid yield, and lipid coefficient of T. cutaneum were measured after the sixth day of fermentation and were 22.76 g/L, 24.0%, 5.46 g/L, and 16.1%, respectively. Therefore, elephant grass is a promising raw material for microbial oil production by T. cutaneum.
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 21
·12518-12523
·
IF 3.108
Pengfei Zhou,Xuping Wang,Bo Yang,Frank Hollmann,Yonghua Wang
Epoxides are important synthetic intermediates for the synthesis of a broad range of industrial products. This study presents a promising solution to the current limitation of enzyme instability. By using simple deep eutectic solvents such as choline chloride/sorbitol, significant stabilization of the biocatalyst has been achieved leading to more robust reactions while using environmentally more acceptable solvents as compared to ionic liquids.
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危险品化学品经营许可证（带存储）