FUEL
·
2020
·
IF 5.578
Bing Xu,Minghui Tan,Xuemei Wu,Hailun Geng,Faen Song,Qingxiang Ma,Chunhui Luan,Guohui Yang,Yisheng Tan
Dehydroaromatization of propane to high value-added aromatics, especially benzene, toluene and xylene (BTX), has attracted widespread attention. Many works have been done to improve the catalytic performance of gallium loaded HZSM-5 catalysts. However, there were few reports focused on reducing the cracked by-products, such as methane and ethylene, derived from propane cracking reaction on external Brønsted acidic sites of zeolite. Herein, chemical liquid deposition (CLD) method was adopted to passivate the external strong Brønsted acid of Ga/HZSM-5, aiming to increase the most value-added BTX production by suppressing the undesired propane cracking reaction. The content of deposited SiO 2 on the external surface of zeolite was tunable by varying the amount of liquid deposition reagent and duration time of CLD process. The results showed that an appropriate content of SiO 2 on external surface of catalyst was beneficial to disable the external strong Brønsted acid sites. Due to depressing the undesired propane cracking reaction, BTX selectivity of 55% with propane conversion of 49% was achieved on Ga/Z5-4Si catalyst, higher than those of Ga/HZSM-5. Otherwise, prolonging the duration time of CLD process narrowed the micropore mouth size of zeolite, which could enhance the shape selective effect of Ga/ZSM-5 to increase the proportion of para-xylene in total xylene products.
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高影响因子
RSC Advances
·
2020
·Vol. 10
·期 50
·29618-29626
·
IF 3.119
Yanming Jia,Qinghua Shi,Junwen Wang,Chuanmin Ding,Kan Zhang
Hierarchical nano-ZSM-5 zeolites (Z5-X) with different grain sizes were synthesized by varying amounts of 3-glycidoxypropyltrimethoxysilane (KH-560) in the hydrothermal synthesis strategy. Moreover, the conventional ZSM-5zeolite(Z5), which was prepared without KH-560, was used as the reference sample. The crystalline phases, morphologies, porous characteristics, Si/Al molar ratios and acidic properties of all fresh catalysts were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), N2 adsorption–desorption, inductively coupled plasma atomic emission spectroscopy (ICP) and temperature programmed desorption of ammonia (NH3-TPD) techniques. Results show that the grain size and strong acid amount of zeolite decreased with the increasing amount of KH-560. The micropore surface areas and the corresponding volume of Z5-X changed less compared with Z5. Consequently, the high shape-selectivity of zeolite was preserved well under the addition of KH-560. However, the mesopore surface areas and the corresponding volume increased significantly with the increasing amount of KH-560. Benefiting from the abundant hierarchical structure, the Z5-X catalysts exhibited a larger coke capacity than the Z5 catalyst. The coke depositions of all the deactivated catalysts were characterized by the thermogravimetric technique (TG), and the results are indicative of the decreased average rate of coke deposition with an increasing amount of KH-560, which could result from the gradually reduced strong acid amount and the nano-sized crystallites. The catalytic performance of methanol-to-aromatics (MTA) indicates that the Z5-0.12 catalyst exhibited higher catalytic activity and selectivity of BTX as the reaction was prolonged, which could result from the synergistic effect among the proper strong acid amount, the smaller zeolite grain size, and the abundant hierarchical structure.
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PubMed
高影响因子
GREEN CHEMISTRY
·
2020
·Vol. 23
·期 1
·405-411
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IF 9.48
Huiyong Wang,Jingjing Cui,Yuling Zhao,Zhiyong Li,Jianji Wang
Ionic liquids (ILs) have been widely studied as effective reaction media or catalysts for the conversion of renewable resources to 5-hydroxymethhylfurfural (5-HMF). However, the separation of 5-HMF from ILs remains a significant challenge. Thus, the aim of this work is to develop a useful guideline for the selection and design of greener solvents for efficient separation of 5-HMF from ILs by a simple solvent extraction approach. To this end, 9 kinds of low-toxic and medium boiling point organic solvents and 10 kinds of ILs typically used in biomass conversion have been evaluated for the separation of 5-HMF. The effects of the solvent hydrogen bond acceptor capacity, anion type and cationic structure of the ILs on the separation of 5-HMF from the ILs are systematically investigated and the molecular interactions among 5-HMF, ILs and the solvent contained in the mixtures have been revealed by FTIR and 1H NMR measurements. It has been found that besides a low mutual solubility with ionic liquids, an ideal solvent should have strong hydrogen bond acceptor properties. At the same time, the interactions between the anion and cation of the ILs and the hydrogen bonding interaction of the anion with 5-HMF are also very important for the separation of 5-HMF. A weak interaction of the anion with 5-HMF and a strong interaction between the anion and cation of the ILs all result in the high extraction efficiency. Under the optimized conditions, the extraction efficiency of 5-HMF from the ILs is up to 61.0%, which is a record-breaking value at the current time. This finding provides a useful guide for the selection of greener solvents for the separation of 5-HMF from ILs.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
·
IF 16.683
Caidi Jin,Ning Xiang,Xiao Zhu,Shuang E,Kuichuan Sheng,Ximing Zhang
5-hydroxymethylfurfural (HMF) can be widely converted into value-added chemicals and fuels production. Herein, we reported a sustainable and efficient approach for synthesizing HMF directly from cellulose. Facile formylation of cellulose with green and recyclable formic acid was developed for cellulose formate (CF) production. CF with special net-like structure and high degree of formyl substitution was prepared. The resultant CF exhibited excellent catalytic conversion and selectivity for HMF production comparable to monomeric glucose as reactant in dimethyl sulfoxide (DMSO)-H 2 O media. In our work, we presented molecular dynamics simulations to elaborate the preferential coordination of DMSO around formyl group, which promoted the solvation of formylated substrate in DMSO-H 2 O mixture, and the HMF yielded could be protected by DMSO without further degradation to levulinic acid or humins.
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高影响因子
JOURNAL OF CHEMICAL RESEARCH
·
2020
·
IF 0.593
Mingguang Zhang,Zhongbao Bi,Yunyun Wang,Yuxun Zhao,Yang Yang,Yongqiang Zhu,Shifa Wang
A new and practical synthesis of 3-chloro-2,4-difluoro-5-hydroxybenzoic acid, a key intermediate for preparing antimicrobial 3-quinolinecarboxylic acid drugs, is synthesized from 2,4-difluoro-3-chlororobenzoic acid. The protocol involves nitration, esterification, reduction of NO2, diazotization, and hydrolysis with a 70% overall yield. The structures of the synthesized compounds are determined by infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-resolution electrospray ionization mass spectrometry. The advantages of this developed synthetic strategy include an improved overall yield and readily controllable reaction conditions.
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高影响因子
CELLULOSE
·
2020
·Vol. 27
·期 6
·3013-3023
·
IF 4.21
Shen Feng,Sun Shuang,Zhang Xiao,Yang Jirui,Qiu Mo,Qi Xinhua
Abstract Direct production of the platform chemical 5-hydroxymethylfurfural (5-HMF) from cellulose is challenging due to the rigid structure of cellulose. Herein, 5-HMF was effectively obtained from cellulose with high loading concentrations (> 20 wt.%) via an Al 2 (SO 4 ) 3 -assisted mechanochemical method. The Al 2 (SO 4 ) 3 not only acted as catalyst for its Lewis and Brønsted acidity, but also assisted the disruption of the hydrogen bonds among cellulose molecules during ball milling pretreatment. The particle size and crystallinity of the cellulose greatly decreased after Al 2 (SO 4 ) 3 -assisted ball milling pretreatment. The effects of various factors, including the organic solvent, reaction temperature and time, catalyst dose, and substrate concentration, on the yield of 5-HMF from cellulose were studied. A yield of 5-HMF up to 43.5% was obtained from cellulose via the developed mechanochemical-assisted method. A 36.1% yield of 5-HMF was retained when the initial cellulose loading concentration was as high as 21.6 wt.%. The green and efficient mechanochemical-assisted method was applicable to the efficient coproduction of 5-HMF and furfural from several waste biomass feedstocks.
Graphic abstract
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2021
·Vol. 32
·期 14
·19284-19296
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IF 2.478
Li Sirui,Zhao Hongwei,Wang He,Zhu Hang,Zhang Hehan,Yu Haitao,Yang Tianye
At present, functional materials such as metal sulfides, metal oxides and so on synthesized with metal–organic frameworks (MOFs) as the general templates or precursors in the field of gas sensing have been a new strategy to improve gas-sensing performance. In this work, a unique MOF-5-derived ZnO nanochains (NCs) sample is synthesized through a conventional solvothermal method with subsequent annealing process. The ZnO NCs-based sensor exhibits outstanding sensing performance such as fast response time (< 1 s) and high response value 34.7 toward 20 ppm triethylamine (TEA). The ZnO NCs sample was characterized by a series of methods (XRD, SEM, XPS and so on). The excellent TEA-sensing properties can be ascribed to the unique nanochain morphology and a plenty of oxygen vacancies of the ZnO crystal through the analysis of the morphology and composition of the sample. In addition, a possible growth mechanism comes up and the sensing mechanism is discussed. The superior TEA sensing performance makes the as-synthesized MOF-5 derived ZnO NCs sample a potential candidate for TEA fast detection.
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高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2020
·Vol. 20
·期 1
·1-14
·
IF 1.134
Jiang Yifei,Liu Yang,Fang Siyuan,Ji Min
In this study, a novel antitumor system was designed on the basis of photodynamic therapy and photothermal therapy using gold nanoshells coated 5-aminolevulinic acid (5-ALA) liposomes (GNALs). As a widely used photosensitizer prodrug, 5-aminolevulinic acid (5-ALA)-derived protoporphyrin
IX (PpIX) can accumulate to a higher level in tumors than in normal tissues. Protoporphyrin IX (PpIX) initiates a series of cytotoxic reactions after irradiation of target tissue with a measured dose of light with appropriate wavelength, which may be dependent on the generation of reactive
oxygen species. Gold nanoshells can strongly absorb NIR lasers at the same time, and can generate hyperthermia to provide photothermic effects. Gold nanoshells coated 5-ALA-Liposomes (GNALs) exhibit a uniform-sized spherical shape of 185.8±0.91 nm, with a zeta potential of 33±1.6
mV. Liposomes with specific sizes ranging from 100 to 200 nm can escape into the tumor interstitial tissue and accumulate preferentially in tumor tissue owing to the EPR effect. In addition, NIR light-excited nanosystems significantly promoted antitumor effects in this study compared to single
photodynamic therapy. It was also found that the increased temperature promoted inhibition rate of SKOV3 cells. The novel drug delivery system shows great potential in photothermal-photodynamic antitumor therapy.
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PubMed
高影响因子
ADVANCES IN POLYMER TECHNOLOGY
·
2020
·
IF 1.539
Yunlong Liu,Jie Guo,Zhuobing Xiao,Dazhao Peng,Ke Song
Separation and purification of active components from biomass by inorganic materials during the pretreatment process of hydrothermal conversion are studied in this work. The batch experiment results show that an initial solution pH of 6 favors chelerythrine adsorption, and the optimum adsorbent dosage is 2.0 g. The adsorption mechanism of ZSM-5 for chelerythrine is investigated by adsorption kinetics, isotherm adsorption models, and thermodynamics analysis. The results show that the kinetics data fit the pseudo-second-order model well (R2 = 0.9991), and the intraparticle diffusion model has 3 diffusion stages, preliminarily indicating that chemisorption plays a major role in the adsorption process, and the sorption mechanism includes intraparticle, external, and boundary diffusion. The adsorption isotherms agree well with the Langmuir model, indicating the occurrence of monolayer molecular adsorption during the adsorption process. Meanwhile, the maximum adsorption capacity is 2.327, 2.072, and 1.877 mg/g at different temperatures (288 K, 298 K, and 308 K), respectively. The thermodynamic data demonstrate that the adsorption process is exothermic and spontaneous in nature. These observed results clearly confirm that ZSM-5 has potential superior properties for the enrichment and purification of alkaloids during the pretreatment of biomass.
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高影响因子
International Journal of Chemical Engineering
·
2019
·
IF 0
Qiuyun Zhang,Xiaofang Liu,Tingting Yang,Quanlin Pu,Caiyan Yue,Shuya Zhang,Yutao Zhang
Direct conversion of fructose into 5-hydroxymethylfurfural (HMF) is achieved by using modified aluminum-molybdenum mixed oxide (S-AlMo) as solid acid catalysts. The synthesized catalyst was characterized by powder XRD, nitrogen adsorption-desorption isotherm, NH3-TPD, and SEM. As a result, the presence of strong acidity, mesostructures, and high surface area in the S-AlMo catalyst was confirmed by nitrogen adsorption-desorption isotherm and NH3-TPD studies. A study by optimizing the reaction conditions such as catalyst dosage, reaction temperature, and time has been performed. Under the optimal reaction conditions, HMF was obtained in a high yield of 49.8% by the dehydration of fructose. Moreover, the generality of the catalyst is also demonstrated by glucose and sucrose with moderate yields to HMF (24.9% from glucose; 27.6% from sucrose) again under mild conditions. After the reaction, the S-AlMo catalyst can be easily recovered and reused four times without significant loss of its catalytic activity.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2014
·
IF 3.785
Meixia Xu,Minjie Sun,Hongzhi Qiao,Qineng Ping,Eltayeb Suliman Elamin
Oral modified-release delivery systems, such as bio-adhesive one, enable drug delivery to affected regions and minimize the side effects by reducing the systemic absorption. Our aim was to develop colon adhesive pellets of 5-aminosalicylic acid (5-ASA) for the treatment of ulcerative colitis . The core of the pellet was formulated from bioadhesive agents, Carbomer 940 and hydroxypropyl cellulose (HPC), by extrusion/spheronization method and coated with Surelease ® as inner layer for waterproof and with Eudragit ® S100 as outer layer for pH control. The rat model of ulcerative colitis was used to evaluate the efficiency of our loaded pellets as a drug carrier. Microcrystalline cellulose 101 (PH 301) was found to be the best agent for pellet core. The ratio of CP940 to HPC should be kept as (1:1) to achieve high bioadhesion. When the amount of Surelease ® was from 16% to 20% and of Eudragit ® S100 was 28%, the dissolution profiles of coated pellets revealed no drug release in the artificial gastric fluid (pH 1.0) within 2 h and less than 10% was released in phosphate buffer (pH 6.0) within 2 h whereas complete dissolution was observed in colonic fluid of pH 7.4 for 20 h. The animal experiment showed that 5-ASA loaded colon adhesive pellets had optimal therapeutic effect. We showed a novel approach to prepare effective bioadhesive pellets as colon targeted drug delivery system .
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高影响因子
Journal of Energy Chemistry
·
2017
·
IF 2.594
Xiaoyu Wang,Wei Chen,Zheng Li,Xianhai Zeng,Xing Tang,Yong Sun,Tingzhou Lei,Lu Lin
In this study we report a new reaction pathway in which the hydroxyl and the aldehyde groups of 5-hydroxymethyl furfural were aminated respectively. Hydroxyl group was aminated via Ritter reaction followed by direct reductive amination of aldehyde group. For the Ritter reaction of 5-hydroxymethyl furfural, mixture of trifluoromethane sulfonic acid and phosphoric anhydride showed good performance and the intermediate N -acyl-5-aminomethyl furfural with the highest yield of 89.1 wt% was obtained. Optimization of direct reductive amination of 2,5-bis(aminomethyl) furan was conducted and a yield of 45.7 wt% was achieved. This study presents a simple way for preparing bis(amino)furans from renewable biomass based 5-hydroxymethyl furfural, which enriches the biorefinery concept from biomass.
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高影响因子
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