Molecular Catalysis
·
2017
·
IF 0
Shuang Chu,Li’na Yang,Xingcui Guo,Linlin Dong,Xiufang Chen,Yaru Li,Xindong Mu
The catalytic behavior of a series of MFI catalysts with different Si/Al ratio (25–300) in the direct aqueous-phase hydrolysis of α-cellulose was studied. The effects ultrasonic pretreatment time, ZnCl 2 content, zeolite pore structure and acid-basic properties on catalyst activity and products distribution were systematically investigated. The results indicated that HZSM-5 with lower Si/Al ratio was beneficial for production of glucose and LA from α-cellulose. Ultrasonic pretreatment could decrease the degree of crystallinity and polymerization of α-cellulose, enhance the accessibility of acid sites and ZnCl 2 to the loosened amorphous regions of α-cellulose in water, and improve the hydrolysis efficiency of α-cellulose. The desilicated ZSM-5 (HZSM-5-DS(0.2)) showed much higher catalytic activities as compared to commercial ZSM-5 and α-cellulose conversion reached 76.5% over HZSM-5-DS(0.2) at 200 °C. Catalytic conversion of α-cellulose consisted of at least three important parallel reactions under the present hydrothermal conditions and a plausible pathway was proposed. Effective control of these reactions would be helpful to further maximize the target product yield during the catalytic conversion of α-cellulose.
研究领域:
化学工程
·
生物质转化
✓ 已验证
DOI
Catalysis Science & Technology
·
2016
·Vol. 6
·期 8
·2647-2652
·
IF 5.287
Hualei Hu,Jinghui Lyu,Jiayao Rui,Jie Cen,Qunfeng Zhang,Qingtao Wang,Wenwen Han,Xiaonian Li
Ethylbenzene is the major side product in benzene alkylation with methanol and it is difficult to be suppressed over hierarchical porous ZSM-5. Moreover, the separation of ethylbenzene from xylene still remains a great challenge. Our research indicated that ethylbenzene formation could be highly suppressed by changing the Si/Al ratio of the catalyst. Hierarchical porous ZSM-5 catalysts with different Si/Al ratios were prepared via reducing the amount of Al in the solvent evaporation assisted dry gel conversion method. In this method, tetra-n-propylammonium hydroxide was used as the direct agent to create micropores, and hexadecyltrimethoxysilane was added to create additional porosities by forming organic assemblies which occupied a certain space between zeolitic walls. The catalyst with a Si/Al ratio of 1800 could achieve high benzene conversion (59.5%) and high xylene selectivity (39.0%) as well as excellent suppression of ethylbenzene formation (<0.1%).
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 43
·33809-33813
·
IF 3.84
Bo Xiao,Ying Fan,Rui-han Gao,Peng Chen,Jian-xin Zhang,Qing-di Zhou,Sai-Feng Xue,Qian-Jiang Zhu,Zhu Tao
A one-pot strategy was employed to synthesize a series of cucurbit[5]uril-anchored (Q[5]-anchored) polymers with high yields. The acrylic acid (AA) monomer, an ammonium persulfate salt (APS) initiator, and an oxidant were used in the polymerization. The Q[5]-anchored polyacrylic acid aggregates (Q[5]-PAA) have been characterized by 1H NMR, 13C NMR, 2D NMR, FTIR, TGA, GPC, TEM and SEM measurements. The experimental results confirm that PAA chains can be grafted to Q[5] in a controlled manner through an in situ radical polymerization approach. The effects of acrylic acid and Q[5] feed mass and APS concentration on the formation of polymer nanocapsules have been investigated. The experiments reveal that the feed mass of acrylic acid greatly influences the properties of Q[5]-PAA when the ratio of Q[5]/APS is fixed at 0.5. In particular, when APS/Q[5] = 46 and 72, vesicle structures are observed in the Q[5]-anchored polymers. Moreover, such polymer nanocapsules show selective absorption of some volatile compounds, particularly methanol.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Applications in Energy and Combustion Science
·
2021
·
IF 0
Huiyan Zhang,Bingbing Luo,Kai Wu,Han Wu,Jiajun Yu,Siyu Wang
Catalytic fast pyrolysis of lignin is easy to cause agglomeration and coking, resulting in low-yield aromatic hydrocarbons. Catalytic pyrolysis of modified lignin combined with metal-modified HZSM-5 was proposed to enhance the aromatic yield. The experiment results showed that chemical modification with Ca(OH) 2 not only inhibited the agglomeration behavior of lignin but also increased the yield of light phenolic compounds. Moreover, Ca 2+ -loaded lignin combined with metal-modified HZSM-5 was conducive to the formation of aromatics. The total yield of aromatics from the catalytic fast pyrolysis of Ca 2+ -loaded lignin over Zn/HZSM-5 was improved from 31.1 to 46.1 mg/g. The mechanism insight showed that Ca 2+ modification realized the chemical combination between Ca 2+ and the functional groups which are responsible for the agglomeration of lignin, and then the introduction of the Zn species suppressed the hydrogen transfer reaction and enhanced the dehydrogenation pathway, resulting in the increase of aromatic yield.
研究领域:
化学工程
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能源科学
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材料科学
✓ 已验证
DOI
Crystals
·
2020
·Vol. 10
·期 9
·781
·
IF 2.404
Qintong Huang,Rui Li,Guangying Fu,Jiuxing Jiang
ZSM-5 zeolites are commonly used as a heterogeneous catalyst for reactions. Four ZSM-5 catalysts (with various crystallite sizes and a similar ratio of Si/Al) and their ball-milling/surface-poisoning derivates were used to convert L-lactic acid to L, L-lactide. The reaction products were analyzed by three independent analytical methods (i.e., Proton nuclear magnetic resonance (1H NMR), high-pressure liquid chromatography (HPLC), and chiral gas chromatography (GC)) for determining the L, L-lactide yield and L-lactic acid conversion. A clear size effect, i.e., smaller catalysts providing better performance, was observed. Further ball-milling/surface-poisoning experiments suggested that the size effect of the ZSM-5 catalysts originated from the diffusion-controlled nature of the reaction under the investigated conditions.Keywords:ZSM-5 zeolites;L,L-lactide;size effect;diffusion control
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Zheng Zhang,Ying Liu,Yunsheng Chen,Lexiang Li,Ping Lan,Dannong He,Jie Song,Yixin Zhang
5-Aminolevulinic acid (ALA)-loaded nanoethosome (ALA-ES) gels are successfully prepared to realize a transdermal delivery of ALA, and they provide a feasible approach for the photodynamic therapy (PDT) of hypertrophic scars (HS). Herein, the morphological and physicochemical features indicate that ALA-ES is stable in gel matrix. In vitro transdermal penetration studies suggest ALA-ES gels can overcome the compact dermal barrier and deliver more ALA into human HS tissue. In vivo delivery studies further reveal that ALA-ES gels can penetrate into rabbit HS tissue to facilitate ALA accumulating in hypertrophic scar fibroblast (HSF) and converting into protoporphyrin IX in the cytoplasm. Utilizing transmission electron microscopy, the visual in vivo penetration process indicates ALA-ES penetrate into HS tissue utilizing its deformable membrane, enters HSF by a pinocytotic-like mechanism, and then releases ALA in the cytoplasm. Subsequently, PDT efficacy is assessed using rabbit HS models. The morphological and histological analysis reveal that ALA-ES gels can improve HS by promoting HSF apoptosis, remodelling collagen fibers and increasing MMP3 expression. The results demonstrate that ALA-ES gels are suitable in clinical treatment of HS and make a substantial progress within the field.
研究领域:
药剂学
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医学
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生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
Biosensors-Basel
·
2022
·Vol. 12
·期 7
·544
·
IF 5.743
Jingyi Li,Ning Zhang,Xin Yang,Xinting Yang,Zengli Wang,Huan Liu
This study presents a novel composite thin film based on rhodamine B encapsulated into MOF-5 (Metal Organic Frameworks) as a fluorescence sensor for the real-time detection of the freshness of chilled pork. The composite film can adsorb and respond to the volatile amines produced by the quality deterioration of pork during storage at 4 °C, with the fluorescence intensity of RhB decreasing over time. The quantitative model used for predicting the freshness indicator (total volatile base nitrogen) of pork was built using the fluorescence spectra (excited at 340 nm) of the RhB@MOF-5 composite film combined with the partial least squares (PLS) algorithm, providing Rc2and Rp2values of 0.908 and 0.821 and RMSEC(root mean square error of calibration) and RMSEP (root mean square error of prediction) values of 3.435 mg/100 g and 3.647 mg/100 g, respectively. The qualitative model established by the partial least squares discriminant analysis (PLS-DA) algorithm was able to accurately classify pork samples as fresh, acceptable or spoiled, and the accuracy was 86.67%.
研究领域:
食品科学
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传感技术
·
生物化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2019
·
IF 4.191
Yazhen Chen,Hetong Lin,Yanjie Li,Mengshi Lin,Jicheng Chen
Non-enzymatic browning of vinegar soaked-soybean residual solution was investigated using a model solution. A glycine-fructose-gallic acid model system was proposed by analyzing reducing sugars, amino acids, total phenolics, and pH value of the vinegar soaked-soybean residual solution. Based on the proposed model, the kinetics of 5-hydroxymethylfurfural (5-HMF) formation was also studied. The results showed that Maillard reaction and sugar pyrolysis might be the accurate mechanisms of non-enzymatic browning in vinegar soaked-soybean residual solution. The formation of 5-HMF in the model solution exhibited characteristics of the first-order kinetic model at temperature from 60 to 140 °C. The frequency constant k f was 450.65 /h, and the apparent activation energy E a was 20.15 kJ/mol. Acetic acid, Fe 2+ , and Fe 3+ significantly enhanced the browning rate and 5-HMF formation; whereas Ca 2+ , Mg 2+ , Na + , glucose oxidase, and H 2 O 2 inhibited the browning rate.
研究领域:
食品科学
·
化学动力学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2019
·
IF 2.938
Liqin Wang,Heqin Guo,Qiang Wang,Bo Hou,Litao Jia,Jinglei Cui,Debao Li
Furfural, generally achieved from hemicelluloses and its derived pentose, is a high value-added product. The formation of furfural from cellulose and hexose remains challenging. The acid sites in zeolites are the major active sites for preparing furfural from hexose. The catalytic performance of zeolites can be improved by increasing the number of active sites for the preparation of furfural. In this work, HZ-Na free-m and HZ-Na-m zeolites were prepared through without or with adding Na + ions in the mother gels, respectively. GHB (hydrolysate of GBL) was the active site for the formation of acyclic fructose precursor (Intermediate 2). Acyclic fructose production and the following dehydration for producing furfural were favored by the middle strong and strong Brønsted acids in the channels of HZSM-5. Meanwhile, middle strong and strong Brønsted acids were favored the production of HMF from fructose and furfural from xylose. The exterior weak Lewis acid of HZSM-5 could promote the formation of soluble oligomers. The soluble oligomers were composed by HMF and furfural through condensation, etherification, nucleophilic attack and electrophilic attack. HMF molecule was easy to participate in the production of soluble oligomers than furfural molecule over exterior weak Lewis acid of HZSM-5.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
TETRAHEDRON LETTERS
·
2018
·Vol. 60
·期 5
·402-406
·
IF 2.125
Xingquan Xiong,Chao Yi,Xu Liao,Shilin Lai
A series of 5-substituted-1 H -tetrazoles have been efficiently synthesized in moderate to excellent yields (68–90%) under mild reaction conditions by combining aryl aldehydes, hydroxylamine hydrochloride with sodium azide in the presence of catalytic amount of Cu(OAc) 2 in deep eutectic solvent (DES). The new synthetic method has many advantages, such as high conversion, green reaction medium, easy work-up, low cost, and environment friendly.
研究领域:
有机化学
·
药物化学
·
绿色化学
·
合成方法学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2020
·
IF 3.905
Chaoyue Shen,Xiying Jia,Yifei Chen,Licong Lu,Fangqi Wang,Yi Wei,Fengwen Yu
Molten carbonate pyrolysis is proposed to convert digestate (DE) into biobased monophenols coupled with a metal-modified HZSM-5 catalyst. The results indicated that Fe/HZSM-5 was the most suitable catalyst for this process. The optimum reaction conditions for the process were WHSV = 15 h −1 at a pyrolysis temperature of 430 °C and a catalytic cracking temperature of 475 °C, and 79.22 % of monophenol components were achieved in the bio-oil. A kinetic study on the digestate with carbonates indicated that the alkali metal ion in the molten carbonates attached to the β-O-4 bonds and branch methoxy group of lignin, which promoted the removal of these functional groups, resulting in a reduction in the activation energy during monophenol generation. The Fe/HZSM-5 catalyst reinforced the generation of monophenol compounds in both concentration and yield. Compared with molten carbonate pyrolysis, the Fe on the catalyst not only benefited the breaking of β-O-4 bonds and methoxy groups of lignin but also lowered the temperature during molten carbonate pyrolysis to minimize the secondary cracking of phenolic compounds.
研究领域:
生物化学
·
催化反应工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Xiaoxian Li,Yuanzhe Gong,Qi Lu,Min Lin,Jian Liu,Yulong Wu
In this work, the hierarchical pore HZSM-5 zeolite was synthesized by the method of alkali treatment, and the bimetallic loading of Mo and Cu was investigated for the hydrothermal aromatization of stearic acid. After alkali treatment, the pore size of HZSM-5 increased, but the acid sites decreased. The metal loading reintroduced the Lewis acid sites, greatly increasing the ratio to Brönsted acid sites. Therefore, the treated catalyst achieved higher hydrothermal stability while maintaining the high activity of hydrothermal aromatization of stearic acid. Mo0.02Cu0.01/Z-0.2M achieved excellent activity in the stearic acid hydrothermal aromatization with a high overall TEX (toluene, ethylbenzene, and xylenes) yield of 50.19 wt %, including 10.30 wt % toluene, 3.82 wt % ethylbenzene, and 36.07 wt % xylene. In addition, Mo0.02Cu0.01/Z-0.2M still showed excellent catalytic activity while applied in the system of the simulated microalgal bio-oil. As the reactant changed to the mixture of stearic acid and hexadecanamide, an overall TEX yield of 34.11 wt % was obtained at 450 °C. These results demonstrate the excellent hydrothermal aromatization ability of the MoCu-supported hierarchical pore ZSM-5 zeolite, which provides the potential to produce value-added chemicals from algal biomass.
研究领域:
催化化学
·
可再生资源转化
·
能源材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）