ENERGY & FUELS
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2018
·
IF 3.024
Zihao Zhang,Hao Cheng,Hao Chen,Jing Li,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
Hierarchical HZSM-5 with tunable acidity, zeolitic crystallinity, and porosity were prepared using different organosilanes and used for the production of aromatics from the catalytic fast pyrolysis (CFP) of rice straw. As the chain length of organosilanes changed, the composition of the products including aromatics and coke varied greatly. Additionally, the introduction of ammonium ions into organosilanes led to a lower yield of aromatics and a higher yield of coke. Transmission electron microscopy, temperature-programmed desorption of NH3, N2 adsorption–desorption (Brunauer–Emmett–Teller), and X-ray diffraction were used to explore the influence of the morphological structure, acidity distribution, textural properties, and crystallinity on the CFP of rice straw. The results indicated that the crystallinity, textural properties, and total acidity had a great influence on the synthesis of aromatics.
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KOREAN JOURNAL OF CHEMICAL ENGINEERING
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2019
·Vol. 36
·期 7
·1042-1050
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IF 2.476
Wang Shuai,Lyu Li,Sima Guobao,Cui Ying,Li Baoxia,Zhang Xueqin,Gan Linhuo
A sulfonated lignin-derived mesoporous carbon (LDMC-SO 3 H) was prepared from kraft lignin (KL) using phenolation and soft-template method followed by sulfonation. LDMC-SO 3 H bearing a sulfonic acid density of 0.65 mmol/g possessed a well-ordered 2D hexagonal mesoporous characteristics with mesopore volume of 0.067 cm 3 /g and specific surface area of 262 m 2 /g as well as mesopore size of 3.42 nm. A high 5-hydroxymethylfurfural (5-HMF) yield of 98.0% with a full fructose conversion was obtained using LDMC-SO 3 H as catalyst under the optimized reaction conditions of reaction temperature and time of 140 °C and 120 min, initial fructose concentration of 100 g/L, catalyst load of 0.1 mg/mg in DMSO. Furthermore, there was no obvious decrease in 5-HMF yield (≥95.0%) within the five-cycle experiment, highlighting the superior reusability and stability of LDMC-SO 3 H in fructose-to-5-HMF transformation.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Fuxiang Feng,Li Wang,Xiangwen Zhang,Qingfa Wang
Ultrathin Ni/ZSM-5 nanosheet catalysts with different acid concentrations, B/L (Brønsted/Lewis acid sites) ratios, and nanosheet thicknesses are designed for the hydroconversion of oleic acid into aviation-fuel-range alkanes (AFRAs). The role of acid concentration/distribution and nanosheet thickness was investigated. High acid concentration enhances the hydrodeoxygenation (HDO) reaction and intrinsic deoxygenation activity because of the synergistic effect between acid sites and metal sites. The selective cracking reaction can be enhanced by tailoring nanosheet thickness and acid distribution. The thin nanosheet favors isomerization, the selective cracking reaction, as well as the generation of central branched isomers. External acid sites dominate the primary cracking and central C–C cracking of the deoxygenated products, but internal acid sites promote the deeper cracking and terminal C–C cracking. Formation of aromatics is thoroughly suppressed at low reaction temperature (≤533 K). A high AFRA yield of 41.4% is achieved over the 3 nm nanosheet catalyst with Si/Al = 300 and B/L = 0.18.
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INDUSTRIAL CROPS AND PRODUCTS
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2018
·
IF 3.849
Binglin Chen,Guizhuan Xu,Zhangbin Zheng,Dongxiang Wang,Caihong Zou,Chun Chang
An efficient and green conversion process of producing 5-ethoxymethylfurfural (EMF) from corn stover was developed. The solid zeolite USY provided the good catalytic performance in ethanol medium with tetrahydrofuran (THF) as co-solvent, which can promote the formation of EMF, reducing the formation of ethyl levulinate and 5-hydroxymethylfurfural. The reaction conditions were optimized via response surface methodology leading to a maximum EMF yield of 21.8% in ethanol/THF (volume ratio 1:1) under the conditions of 168 °C, 1 wt% USY loading and 2.9 h. Meanwhile, USY can be reused in five consecutive reaction runs with high activity, upholding the same initial activity and structural integrity. A plausible reaction pathway for the conversion of corn stover to EMF in ethanol/THF medium was further proposed. This study showed that the improved catalytic system presents an efficient method for direct production of EMF from lignocellulosic biomass.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2019
·
IF 4.182
Zeyu Han,Feng Zhang,Xinhong Zhao
Currently, there remains a great challenge to synthesize zeolites in an energy-saving and environmentally friendly manner. Herein we report a novel solvent-free route of synthesizing Fe-ZSM-5 zeolite, which is featured by using Fenton's reagent as a promoter. The influences of crystallization time, amount of hydrogen peroxide and low-temperature pretreatment on the synthesis of Fe-ZSM-5 zeolite were investigated in detail. The results indicate that the combination of solvent-free synthesis with Fenton's reagent can facilitate the rapid crystallization of Fe-ZSM-5 zeolite. The resultant Fe-ZSM-5 zeolite was used as a catalyst for phenol hydroxylation, and characterized by XRD , SEM, ICP-AES, N 2 physisorption and UV–Vis diffuse reflectance spectroscopy. Notably, it exhibits a much better catalytic performance as compared with the reference catalyst by conventional solvent-free method. The observed enhanced catalytic performance for this Fe-ZSM-5 catalyst is attributed to its larger BET surface area and mesoporous volume as well as enrichment towards phenol.
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ACS Catalysis
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2019
·
IF 12.221
Yaqi Liu,Hong-Yan Ma,Da Lei,Lan-Lan Lou,Shuangxi Liu,Wuzong Zhou,Gui-Chang Wang,Kai Yu
The aerobic oxidation of alcohols and aldehydes over noble metal catalysts is a critical reaction for the catalytic conversion of carbohydrates into value-added chemicals from biomass. However, to fully understand the reaction mechanism, in particular, the role of O2 and the generated active oxygen species in these reactions is still a challenging target. In the present work, the sub-10 nm Pt nanocrystals with cubic (Pt-NCs), octahedral (Pt-NOs), and spherical (Pt-NSs) morphologies were synthesized and used as catalysts in aerobic oxidation of 5-hydroxymethyl-2-furfural (HMF). Through experimental and computational investigations, the facet-dependent O2 conversion pathway and catalytic oxidation performance were discussed. The molecular O2 tends to be dissociated to generate •OH on a Pt(100) surface but prefers to be reduced to •O2– on a Pt(111) surface. Moreover, Pt-NCs enclosed by the {100} facets exhibited significantly enhanced catalytic activity compared to Pt-NOs enclosed by the {111} facets and Pt-NSs, in particular, for the alcohol oxidation step. On the basis of the experimental data and density functional theory (DFT) calculations, an active oxygen species promoted dehydrogenation mechanism for aerobic oxidation of HMF was proposed. The dehydrogenation of the alcohol group is more favorable on the Pt(100) surface with assistance of •OH, which is the dominant active oxygen species on the Pt(100) surface. We anticipate that this work would provide new insight into the role of active oxygen species in aerobic oxidation of alcohols and aldehydes over noble metal catalysts.
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FOOD AND AGRICULTURAL IMMUNOLOGY
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2019
·
IF 2.398
Xiangren Meng,Dejun Ji,Wei Zhang,Lixia Fu,Hengpeng Wang,Peng Wu
The nitrofurans were recently banned from use in livestock production due to their potential carcinogenicity in humans. Therefore, the screening of foods from animal origins for nitrofurans became mandatory. A rapid, specific and sensitive method based on immunochromatographic strip test has been developed for the determination of 3.5-dinitro-N’-(5-nitrofurfurylidene) salicylic acid hydrazide (DNSH) residues in fish. Fish samples were prepared by ultrasonic bath extraction, centrifugation, filtration, drying and res-suspension. The antigen (DNSH-glutaraldehyde-ovalbumin) and a goat anti-mouse IgG antibody were drawn onto a nitrocellulose membrane as the test and control line, respectively. Under optimal conditions, the DNSH cut-off limits for the test strips were determined as 10 ng/mL in 0.01 M phosphate buffered saline and 25 ng/mL in fish samples, with results obtained within 5min. Our data suggests this immunochromatographic assay can be used for the sensitive, rapid, and specific on-site screening of DNSH in fish products.
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FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Qingfeng Che,Minjiao Yang,Xianhua Wang,Xu Chen,Wei Chen,Qing Yang,Haiping Yang,Hanping Chen
Dual catalysts are proposed in this study to convert biomass pyrolysis vapors into aromatics. Metal oxides (CaO, Al 2 O 3 , and ZnO) and ZSM-5 were introduced into the catalytic upgrading process. In the pyrolysis process without ZSM-5, the addition of CaO effectively removed carboxylic organics and methoxyphenols, reducing the product yield with a hydrogen to carbon ratio of 0, and the size of phenol compounds. The addition of Al 2 O 3 greatly promoted the cracking of oxygenates with molecular weight above 109 g mol −1 , such as large-size methoxyphenols and sugars. It is found that the upgraded pyrolysis volatiles are more conducive to conversion for aromatics with a ZSM-5 catalyst. The addition of CaO increased the selectivity of xylene (15.9%), while Al 2 O 3 promoted the selectivity of toluene (18.3%). The highest yield of aromatics was obtained with CaO-ZSM-5 dual catalyst system, which was boosted by 6.14% compared to that of pure ZSM-5. To explore more effective methods for aromatics production, the arrangement of catalysts and temperature condition were investigated. Mixing CaO with biomass produced more aromatics than other methods, and the most suitable temperature for the formation of aromatic hydrocarbons was 600 °C.
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Catalysts
·
2018
·Vol. 8
·期 12
·633
·
IF 3.465
Jingxuan Long,Wenfeng Zhao,Yufei Xu,Hu Li,Song Yang
Catalytic reduction of 5-hydroxymethylfurfural (HMF), deemed as one of the key bio-based platform compounds, is a very promising pathway for the upgrading of biomass to biofuels and value-added chemicals. Conventional hydrogenation of HMF is mainly conducted over precious metal catalysts with high-pressure hydrogen. Here, a highly active, sustainable, and facile catalytic system composed of K2CO3, Ph2SiH2, and bio-based solvent 2-methyltetrahydrofuran (MTHF) was developed to be efficient for the reduction of HMF. At a low temperature of 25 °C, HMF could be completely converted to 2,5-bis(hydroxymethyl)furan (BHMF) in a good yield of 94% after 2 h. Moreover, a plausible reaction mechanism was speculated, where siloxane in situ formed via hydrosilylation was found to be the key species responsible for the high reactivity.Keywords:biomass conversion;biofuels;hydrogenation;green chemistry;sustainable catalysis
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BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Qingfeng Che,Minjiao Yang,Xianhua Wang,Qing Yang,Yingquan Chen,Xu Chen,Wei Chen,Junhao Hu,Kuo Zeng,Haiping Yang,Hanping Chen
The micropores present in ZSM-5 are beneficial to the production of aromatic compounds in biomass catalytic pyrolysis, although the small pore size leads to severe coke deposition on the catalyst. In this study, a micro-mesoporous structured ZSM-5 zeolite catalyst was synthesized and modified with green templates (sucrose, cellulose, and starch) to introduce additional mesopores. It was found that the catalysts modified using the sucrose and cellulose templates only exhibited a slight increase in their micropore volumes, while the mesopore volume of ZSM-ST (modified with the starch template) reached up to 0.359 cm 3 /g. This increase promoted the cracking of bulky oxygenates and suppressed the polymerization reaction on the ZSM-5 surface, thereby producing a greater number of aromatic products. Moreover, the benzene, toluene, and xylene (BTX) yields exhibited a positive correlation with the catalyst mesopore volume, with the highest BTX yield of 91.84 mg/g being obtained with 10% starch addition.
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
·
IF 4.784
Xiaoxiao Sun,Chao Liu,A.M. Omer,Wuhuan Lu,Shuxing Zhang,Xun Jiang,Hongjie Wu,Di Yu,Xiao-kun Ouyang
To develop relatively green and ecofriendly smart vehicles for colon-specific drug delivery, carboxymethyl cellulose (CMC) and chitosan (CS) pH-sensitive biopolymers were used in this study. To overcome the weaknesses of CMC carriers, such as poor mechanical performance and an explosive drug release, zinc oxide (ZnO) nanoparticles were incorporated into CMC beads and then coated with a CS layer via a self-assembly technique to form core–shell polyelectrolyte complexes. An anticancer drug, 5-fluorouracil (5-FU), used as a model drug, was loaded into ZnO/CMC/CS bio-nanocomposite beads. Fourier transform infrared spectroscopy , scanning and transmission electron microscopy , and thermogravimetric analysis were used to characterize the chemical structure, morphological changes, and thermal properties of the developed drug carrier, respectively. By studying their swelling and in vitro 5-FU release profiles under simulated gastrointestinal conditions, the pH sensitivity of the developed bio-nanocomposite hydrogel beads could be investigated. The obtained beads with reduced porosity could effectively encapsulate 5-FU and showed self-sustained release behavior depending on the concentrations of CMC, CS, and ZnO nanoparticles. The developed beads also demonstrated a capacity for biodegradation. The results indicated that the ZnO/CMC/CS bio-nanocomposite beads exhibited pH-sensitivity and could be applied efficiently as biodegradable carriers for colon-specific 5-FU delivery.
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高影响因子
ChemCatChem
·
2018
·Vol. 10
·期 24
·5619-5626
·
IF 4.674
Xing Yu,Cunhui Zhou,Xinqing Chen,Peng Gao,Minghuang Qiu,Wenjie Xue,Chengguang Yang,Hanqin Zhao,Hongjiang Liu,Ziyu Liu,Yuhan Sun
Graphical CatalyZSM-5 : Well crystallized hollow fibers assembled by c -axis oriented ZSM-5 crystals were successfully synthesized via a facile one-pot solvent-free route, using quartz fiber as silicon substrate and NH 4 HCO 3 as the growing inhibitor on the crystal faces. The obtained ZSM-5 hollow fibers gave a hierarchical structures composed by micro-, meso- and macropores exhibiting excellent performance in methanol to gasoline (MTG) reaction with higher C 5+ selectivity and longer lifetime due to the improved mass transfer inside the unique hollow fiber structure. Well crystallized hollow fibers assembled by c -axis oriented ZSM-5 crystals were successfully synthesized via a facile one-pot solvent-free route, using quartz fiber as silicon substrate and NH 4 HCO 3 as the growing inhibitor on the crystal faces. The immigration of silica inside the quartz fibers formed the hollow morphology and the shell of hollow fiber was composed by the ZSM-5 crystals. In addition, the length of c -axis of ZSM-5 could be controlled by the amount of NH 4 HCO 3 , which selectively inhibited the growth on (010) surface. The obtained ZSM-5 hollow fibers gave a hierarchical structures composed by micro-, meso- and macropores. Catalytic tests for methanol to gasoline (MTG) revealed that the resultant ZSM-5 hollow fiber exhibited excellent performance with higher C 5+ selectivity and longer lifetime due to the improved mass transfer inside the unique hollow fiber structure.
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