JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 95
·期 3
·798-805
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IF 2.659
Dan Luo,Shengnan Liu,Wang Yin,Shuqian Xia
BACKGROUND Fast pyrolysis of lignocellulosics has provided an abundant sugar source for production of value-added chemicals, and levoglucosan is the most representative sugar in pyrolysis liquid (bio oil). This paper explored the potential for producing methyl lactate from levoglucosan by employing the mixed catalysts of zeolite tin beta (Sn-Beta) and zeolite hydrogen beta (H-Beta). RESULTS Under the optimal conditions (at 200 °C and mixed catalysts with H-Beta:Sn-Beta ratio of 1:5), the yield of methyl lactate obtained from levoglucosan conversion was as high as 35%. And the yield was comparable to that of methyl lactate obtained from glucose conversion under the similar conditions (at 200 °C and pure Sn-Beta). In order to investigate the reason, a contrasting experiment with glucose as substrate also was carried out with the mixed catalysts. The results indicated that during the levoglucosan conversion process, ‘the methanolysis of levoglucosan’ was likely to compete with ‘the dehydration of glucose’ for the Brønsted acid sites of H-Beta. In addition, the catalytic functions of H-Beta and Sn-Beta, and the reaction pathway were deeply investigated through tracking and comparing the conversion of levoglucosan over mixed H-Beta/Sn-Beta and over pure Sn-Beta catalysts, respectively. CONCLUSION The appropriately lower ratio of H-Beta:Sn-Beta and relatively higher temperature were favorable for the reaction. H-Beta containing Brønsted acid could remarkably accelerate the conversion of levoglucosan and methyl-glucosides to glucose. Sn-Beta containing Lewis acid mainly promoted the retro-aldol condensation of glucose and formation of methyl lactate. © 2019 Society of Chemical Industry
研究领域:
化学工程
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生物质能
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催化化学
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DOI
高影响因子
Catalysts
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2022
·Vol. 12
·期 1
·104
·
IF 4.501
Ying Duan,Qianqian Luo,Renfeng Nie,Jianshe Wang,Yongsheng Zhang,Tianliang Lu,Chunbao Xu
The production of methyl lactate as a degradable polymer monomer from biomass was an important topic for a sustainable society. In this manuscript, glycerol was oxidated to methyl lactate catalyzed by the combination of Au-CuO and Sn-Beta. The influence of Sn content, Sn source, and the preparation conditions for Sn-β was studied. The Au content in Au/CuO was also investigated by varying the Au content in Au/CuO. The catalysts were characterized by XRD, FTIR spectroscopy of pyridine adsorption, and TEM to study the role of Sn and the influence of different parameters for catalyst preparation. After the optimization of reaction parameters, the yield of methyl lactate from glycerol reached 59% at 363 K after reacting in 1.6 MPa of O2for 6 h.Keywords:glycerol;oxidation;methyl lactate;Sn-Beta;Au/CuO
研究领域:
催化化学
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生物质转化
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可持续化学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2021
·Vol. 96
·期 8
·2238-2248
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IF 3.174
Xiao-Yang Yue,Hui-Fang Ren,Chengming Wu,Jun Xu,Jifan Li,Chun-Ling Liu,Wen-Sheng Dong
BACKGROUND Methyl lactate is widely applied in the chemical, food, cosmetics and pharmaceutical industries. The conversion of carbohydrates over heterogeneous catalysts to methyl lactate is a promising environmentally benign process. RESULTS Hierarchical Sn-Beta zeolite (Sn-Beta) and corresponding bimetal-doped Beta zeolites (M-Sn-Beta; M = Zn, In, La, Ga, Ni) were prepared via a novel modified hydrothermal synthesis method to convert carbohydrates into methyl lactate. The introduction of Zn into Sn-Beta considerably improved the yield of methyl lactate from glucose, while for the catalysts containing In, La, Ga and Ni, such improvements were not observed. CONCLUSIONS A methyl lactate yield reaching up to 66.7% was obtained over Zn-Sn-Beta at 220 °C for 6 h. The enhanced catalytic performance was attributed to high Lewis acid density and strength, together with synergistic effects between framework Sn 4+ and Zn 2+ ions of Zn-Sn-Beta. Additionally, Zn-Sn-Beta demonstrated fructose and sucrose conversion into methyl lactate with yields of 68.4% and 70.0%, respectively. The Zn-Sn-Beta catalyst could be re-used at least five times with only a slight loss of methyl lactate yield. © 2021 Society of Chemical Industry (SCI).
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2015
·
IF 3.453
Tingting Lu,Ruren Xu,Wenfu Yan
The initial mixture containing fully hydrolysed tetraethyl orthosilicate (TEOS) and tetraethylammonium hydroxide (TEAOH) solution was treated either by heating at 80 °C or by freeze-drying. After adding an appropriate amount of concentrated hydrofluoric acid , the resulting mixture was crystallized at 150 °C. The heating treated mixture produced polymorph A-enriched zeolite beta while freeze-drying treated mixture gave only normal zeolite beta. The 13 C magic angle spinning nuclear magnetic resonance (MAS NMR) analysis and thermogravimetric analysis (TGA) indicated that a partial decomposition of TEAOH to generate triethylamine (TEA) occurred during the heating dehydration process, which was the only difference compared with the freeze-drying process. Together with the reduced TEAOH, different monoamines as a co-template directed the polymorph A-enriched zeolite beta with the freeze-drying process. Diamines as a co-template directed only the normal zeolite beta. The synthesis cost of polymorph A-enriched zeolite beta can be significantly reduced by lowering the usage of expensive TEAOH and using cheaper monoamines.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Ling Zhang,Yiquan Xie,Yiwen Jiang,Yaobin Li,Chunying Wang,Shichao Han,Huimin Luan,Xiangju Meng,Feng-Shou Xiao
Catalytic combustion at low temperature has been considered as an effective route for removal of indoor HCHO pollutant, and conventional catalysts are supported noble metal nanoparticles, which are costly for wide applications. Solution of this issue is to use relatively low metal catalysts. Herein, we report that Mn-promoted Ag catalyst supported on pure silica Beta zeolite with a good hydrophobicity is very active for catalytic combustion of HCHO. By optimizing the loadings of Ag and Mn, it is found that 10 wt% Ag with 8 wt% Mn (10 %Ag8 %Mn/Beta-Si) exhibits highest activity, giving the complete HCHO conversion at around 45 °C, which steadily outperform the temperatures (70–145 °C) for full oxidation of HCHO reported previously. The choice of Ag loading with 10 wt.% is due to the highest exposed surface of Ag sites, and the use of Mn loading with 8 wt% is assigned to the balance of density and mobility for active oxygen species in the catalysts. The strategy combining the hydrophobic supports with optimized active oxygen species might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of air pollutants in the future.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Kai Gao,Qing Wang,Xuexun Du,Qinglian Wei,Yongmin Huang
Dimethylamine (DMA), which is mostly generated in fine chemical industry, has enormously threatened the public health, therefore should be eliminated from water efficiently. Superior to any other methods to remove DMA, adsorbing it by sorbent could avoid the generation of secondary pollution. Among all the sorbents employed in this study, low Si/Al ratio Beta zeolite synthesized without organic template exhibits the highest performance of adsorbing DMA from water. When the transition-metal cations were introduced by ion-exchange, the adsorption of DMA was enhanced. Subsequently, the saturated adsorbent was heated in air condition, detection results of the off-gas indicated that nearly all of the DMA adsorbed was oxidized and negligible harmful by-product was produced. Beta zeolite adsorption coupled with catalytic oxidation could eliminate DMA efficiently and environmental friendly which has wide application prospects in waterworks.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Shuang Wang,Lipeng Zhou,Beibei Gao,Yunlai Su,Xiaomei Yang
Sn-Beta is a good solid Lewis acid catalyst. Seed-assisted hydrothermal synthesis is a popular method for its preparation. However, the mechanism of seeds in the crystallization process is not clear. Here, the role of seeds in the growth of crystal and the influence on the properties of the corresponding products were studied. The seeds and gel was characterized by XRD , SEM, FT-IR and TG. During the crystallization, it was observed that the seeds were partially dissolved and formed seed fragments in the initial stage. Then the seed fragments acted as the core of the crystals and promoted the crystallization process. Seeds greatly decreased the crystal size of the products as compared with the direct hydrothermal method in absence of seeds. The acidity and catalytic performance of Sn-Beta synthesized via seeds route are similar with those of none-seeds method.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2021
·
IF 5.706
Juan Ye,Chenyu Chen,Ying Zheng,Dan Zhou,Yunzhen Liu,Denglong Chen,Liufang Ni,Gang Xu,Fanan Wang
The selective one-pot synthesis of lactic acid (LA) from cellulose, and further the raw biomass, on heterogeneous catalysts is the key point for the development of biorefinery technology. Herein, we reported an yttrium (Y) modified siliceous Beta zeolites catalyst via two-step post-synthesis for highly efficient conversion of cellulose to LA. Under condition of 220 °C and 2 MPa N 2 , the cellulose could be transformed to LA with a yield of 49.2 % within 30 min, and the substrate can be extended to various raw biomass. It was demonstrated that the dealumination and modification of Y can efficiently modulate the acidity on the surface of zeolite. The dehydration products HMF and other derivatives were suppressed, and the yield of LA was correlated in line with the acid amount, which were attributed to the increased Lewis acidity originated by Y incorporation. These results contribute to the development of the green and efficient synthesis of bio-chemicals.
研究领域:
生物化学
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催化化学
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可再生资源
✓ 已验证
DOI
高影响因子
FUEL
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2023
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IF 7.4
Xin Guo,Zhiyong Ding,Na Kang,Liu Yang,Yuanjiang Wang,Cheng Zhang,Zhaoqiang Li,Tiantian Zhang,Yan Wang,Yu Wang,Hao Qu
The zeolite-based catalyst is a promising option for the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) due to its low toxicity. However, the challenge lies in its low-temperature activity. This study developed a multi-component catalytic system consisting of Ce/Mn/Cu-loaded Beta zeolite to reduce NO x . With fixed contents of Cu and Mn, we investigated the NH 3 -SCR process and the mechanism of action of the rare-earth species (i.e., Ce) in the system. Upon optimization of the content of Ce, the Ce/Mn/Cu-loaded Beta zeolite demonstrated enhanced low-temperature activity compared to samples loaded with Cu or Cu/Mn in the temperature range of 150–250 °C. When Ce was loaded in an appropriate proportion, it regulated the oxidation state of Cu, optimizing active adsorption species for NO and strengthening the strength of Brønsted acid sites in the catalyst. These synergetic effects led to improved NH 3 -SCR catalytic performance. This study can contribute to a better understanding of multiple metal-loaded zeolites in the NH 3 -SCR process and inform future design of Beta-type catalysts.
研究领域:
催化化学
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环境科学
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产品关联
DOI
高影响因子
RSC Advances
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2019
·Vol. 9
·期 7
·3653-3660
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IF 3.049
Guang Xiong,Miaomiao Feng,Jiaxu Liu,Qingrun Meng,Liping Liu,Hongchen Guo
An aerosol-assisted hydrothermal method has been applied to synthesizing hierarchical beta zeolites with SiO2/Al2O3 ratios ranging from 44 to 392 in NaF media. Two different morphologies, including nano-aggregates with interparticle mesopores and plate-like zeolites with intracrystalline mesopores, can be formed depending on the SiO2/Al2O3 ratios of the synthesis gels. A possible mechanism for the formation of the beta zeolites has been proposed. The obtained beta zeolites show hierarchical pores, good Al species distribution and less internal defect sites. Evaluation, by the cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), is consistent with the acidic properties and the pore structure of beta zeolites with different ratios of SiO2/Al2O3.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Wenfeng Hao,Peng Lu,Xiaosheng Wang,Yuxiang Liu
A simple and facile co-calcination strategy of Beta molecular sieves and cerous nitrate is proposed. Based on the results of XRD , UV–Vis, in-situ FTIR, and 29 Si MAS NMR techniques, open-site configurations of Ce(III)O 4 and Ce(IV)O 4 tetrahedrons are observed due to a large ionic radius of Ce 3+ and Ce 4+ ions. Open-site configurations result in a low ratio of BrØnsted and Lewis acid sites in HBeta-Ce-6. In the isomerization of α- pinene, a higher amount of Lewis acid sites increases the yield for camphene . BrØnsted acids are accessible for α- pinene to form limonene due to a high surface area and low coke deposition. Isomorphous incorporation of Ce 3+ occurs and a decreasing selectivity for limonene are observed using regenerated catalysts. These results indicate that co-calcination strategy protects Beta molecular sieves from thermal destruction, endows Beta molecular sieves with a higher relative crystallinity and porosity during calcination .
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2017
·
IF 3.154
Xueke Liu,Peng Wang,Chang Liu,Yiran Liang,Zhiqiang Zhou,Donghui Liu
Beta-cypermethrin (beta-CP), an important pyrethroid insecticide, and its main acid metabolites are frequently detected in human samples. Because beta-CP may pose some risk to human health, we studied dynamics and residues of beta-CP and its metabolites in hen egg, droppings, blood, and 15 other tissues after continuous exposure. A digestive model was then used to study beta-CP’s digestive fate. Beta-CP and its metabolites significantly accumulated in tissues with high lipid contents and were readily transferred to eggs. Beta-CP was mainly metabolized into acid metabolites that accumulated in egg and edible tissues of laying hens, suggesting that humans may be exposed to beta-CP acid metabolites through food.
研究领域:
毒理学
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食品科学
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动物科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）