EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
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2021
·Vol. 2021
·期 29
·3013-3018
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IF 2.524
Yi Wang,Jialu Shen,Yu Huang,Xiang Liu,Qiuxia Zhao,Didier Astruc
Graphical Metal-free H 2 or D 2 evolution is obtained in a few minutes from acid- or base-catalyzed hydrolysis of diboronic acid, respectively, under ambient conditions and is coupled to hydrogenation reactions. Kinetic studies allow proposing mechanisms by considering primary kinetic isotope effects observed for both acid- and based-catalyzed reactions with D 2 O. The efficient production of H 2 from hydrogen-rich sources, particularly from water, is a crucial task and a great challenge, both as a sustainable energy source and on the laboratory scale for hydrogenation reactions. Herein, a facile and effective synthesis of H 2 and D 2 from only acid- or base-catalyzed metal-free hydrolysis of B 2 (OH) 4 , a current borylation reagent, has been developed without any transition metal or ligand. Acid-catalyzed H 2 evolution was completed in 4 min, whereas the base-catalyzed process needed 6 min. The large kinetic isotopic effects for this reaction with D 2 O, deuteration experiments and mechanistic studies have confirmed that both H atoms of H 2 originate from water using either of these reactions. This new, metal-free catalytic system holds several advantages, such as high efficiency, simplicity of operation, sustainability, economy, and potential further use.
研究领域:
化学
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能源科学
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DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 10
·9480-9489
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IF 2.914
Dai Shijin,Zheng Yilin,Zhao Youcai,Li Qiang,Niu Dongjie
Chlorine-containing organic waste (COWs) is a big threat for the waste incineration because of the dioxin generation and equipment corrosion. Recently, dechlorination and detoxification of COWs is emergent in order to lower the environmental risk and treatment costs. In this study, base-catalyzed decomposition processes with different hydroxides, hydrogen donors, and catalysts were conducted for pre-treatment of COWs to reduce organic chlorine content, with the TCB as a model compound and industrial rectification residues for verification. Results showed that maximum chlorine retention efficiency (CRE) of four alkalis followed the order of KOH > NaOH–KOH > NaOH > Mg(OH) 2 , which were 98.3%, 93.4%, 97.2%, and 1.5%, respectively, and could be expressed as an apparent first-order reaction. The differences were resulted from the varying ionic potentials of the metal cations. Hydrogen donors (glycol, glycerol, paraffin oil, and PEG 200) acted as effective dechlorination regents follow the order of PEG > glycol > paraffin oil > glycerol. In addition, Fe, Ni, Cu, and activated carbon catalysts increased the CRE by 68.9% to 92.4%, 91.9%, 89.2%, and 73.3%, respectively. Residue analysis through X-ray diffraction and Fourier transform infrared spectroscopy revealed that KCl, sodium oxalate, and phenol were the main products and a plausible stepwise dechlorination pathway was proposed. The effectiveness of three optimized combinations including NaOH/PEG, KOH/PEG, and NaOH–KOH/PEG (with the Fe catalyst) was confirmed by using them for dechlorinating rectification residues, and they restrained 98.2%, 91.2%, and 94.6% of the chlorine, respectively. The organochlorine content decreased from 19.2 to 1.8% within 180 min, while inorganic chorine content increased from 1.5 to 18.9%, indicating the potential for COWs dechlorination.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Waste and Biomass Valorization
·
2016
·Vol. 8
·期 1
·95-102
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IF 0.915
Zhang Peng,Chang Zhidong,Wang Dongyu,Blamo Benjamin John,Li Wenjun
Biodiesel is an environmentally friendly fuel which can be economically produced by the use of waste culinary oil as raw material and NaOH as catalyst. However, the moisture in waste culinary oil or solid NaOH can affect the distribution of final products. In this paper, the water content of solid NaOH and waste culinary oil were determined to be 4.7 and 1.0 % respectively. A simulated transesterification system of methyl butyrate and n-butanol was catalyzed by anhydrous NaOH which was sintered at 800 °C for 2 h. The moistures in reaction system were imitated by contrived addition of water. Experimental results show that when the water content is 0.25 %, the yield of transesterification achieves the highest, simultaneously, saponification remains at the minimum level. The soybean oil and methanol were investigated as exemplary biodiesel system. The results show that when the water content is 1 %, the yield of biodiesel reaches 98.81 %, which is the highest.
研究领域:
化学工程
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可再生能源
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Chaofeng Huang,Yingshuang Zhang,Hongru Jiang,Chongqing Wang,Hui Wang,Wanyuan Li,Fei Nie,He Lin
Polyester plastics, constituting a substantial segment of the global plastic market, offer considerable potential market for the polyesters recycling. This study proposed an efficient separation technology for waste polyesters through flotation assisted by alkaline-catalyzed alcoholysis modification. The alkaline-catalyzed alcoholysis modification facilitates the selective hydrophilization of waste polyesters, regulating their float-sink behavior in flotation. According to the polyester floatability, the hydrophilicity of the modified polyesters is in order of PA6 > PET ≈ PU > PC > PMMA. Due to the different C–O and C–N bond strength, the modification selectively induced alcoholysis on the polyesters surface, enhancing their hydrophilicity by increasing the number of rough structure and hydrophilic functional groups on surfaces rather than introducing heteroatoms. The sinking products in flotation, including polyamide 6 (PA6), polyethylene terephthalate (PET), and polyurethane (PU), could be separated from the floating products, such as polycarbonate (PC), and polymethyl methacrylate (PMMA). The binary separation was achieved under optimum conditions. The recovery and purity of PA6, PET, and PU could reach 100.0 % and 100.0 %, 100.0 % and 85.7 %, 79.9 % and 83.1 %, respectively. Consequently, the heterogeneous alcoholysis reactivity contributes to the selective hydrophilization of waste polyesters. This study established a hydrophilicity order of modified polyesters, and promoted flotation separation of waste polyesters.
研究领域:
材料科学
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环境工程
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化学工程
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产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 7
·3661-3668
·
IF 3.049
Lei Ao,Wei Zhao,Yin-shuang Guan,Ding-kai Wang,Kai-shuai Liu,Tian-tian Guo,Xing Fan,Xian-yong Wei
The aldol-condensation reaction of biomass-derived furfural and cyclopentanone coupled with hydrogenation/hydrodeoxygenation is a promising route for the production of renewable high-quality diesel or jet fuel. In this paper, we focus on the heterogeneously catalyzed aldol condensation of furfural with cyclopentanone, in order to maximize the yield of 2,5-bis(2-furylmethylidene)cyclopentan-1-one (F2C, a C15 fuel precursor). Experiments were conducted over a series of solid-base catalysts and it was found that potassium fluoride impregnated alumina shown the highest catalytic efficiency. We further investigated the effect of different parameters on the performance of KF/γ-Al2O3, including KF loading amount, solvent, reaction time and temperature. Over KF/γ-Al2O3 with a 33% KF loading amount, the aldol reaction achieved an F2C molar yield up to 95.4% at 333 K within 2 h. Under the nearly optimal condition, the separated solid product is almost F2C with a purity of 100%, providing a high-quality biofuel precursor for the next processing step.
研究领域:
化学工程
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可再生能源
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催化化学
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产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 25
·12318-12323
·
IF 3.925
Wei Xiao,Zihao Wang,Jinxiang Yang,Tianyou Chen,Changfeng Yi,Zushun Xu
Aldol reaction in water can effectively limit the formation of Schiff bases that deactivate active amine sites. To date, regulation of cooperative behaviors and morphologies of polymer-supported acid–base catalysts remains a challenge. Here, we develop a controllable strategy for engineering polystyrene-supported acid–base catalysts by using nanoprecipitation in water. Benzylamine-containing copolymers and catechol-containing copolymers were synthesized and used for nanoprecipitation. Because of the hydrophobic nature of the polystyrene chains, coil-globule collapse not only constructs hydrophobic environments but also brings catechol groups and benzylamine groups in close proximity to enable the synergistic effect. The influence of polymer compositions and effective constituent ratios on catalytic performance was investigated to understand the structure-activity relationships. A postulated catalytic mechanism for polystyrene-supported acid–base catalysts was proposed. Our results demonstrate that this strategy provides access to more efficient polymer-supported acid–base catalysts and has the potential for the construction of other bifunctional catalytic systems in aqueous media.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
ChemCatChem
·
2025
·
IF 3.9
Dancheng Zhu,Yuchen Cao,Yuchen Qian,Weijie Yu,Yuxuan Xu,Hao Xu,Jun Qiao,Chao Shen,Jiabin Shen
Graphical This study develops amino-modified Ti 3 C 2 /Mg 3 Al-LDH composites as solid base catalysts for aldol reactions. The composite reduces surface agglomeration, enhances active site exposure, and increases basicity, achieving 99% product yield under optimized conditions (60 °C, 30 min). It retains > 91% efficiency over five cycles, demonstrating superior stability and catalytic performance compared to non-modified LDHs. Aldol reaction is an important class of industrially catalyzed reactions for synthesizing high-value fine chemicals. Traditionally conducted under alkaline conditions, these reactions often utilize liquid alkali catalysts, which present challenges such as difficult separation and recovery and undesirable side reactions promoted by the catalyst. Solid base catalysts have received much attention and research in recent years to address these issues. In this study, magnesium–aluminum layered double hydroxides (MgAl-LDHs) were synthesized using magnesium chloride hexahydrate, aluminum chloride hexahydrate, and anhydrous sodium carbonate. These were subsequently combined with amino-modified Ti 3 C 2 to form composite materials. Characterization of the prepared Mg 3 Al-LDH/Ti 3 C 2 -NH 2 composites was conducted using X-ray diffractometer (XRD), scanning electron microscope (SEM), infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) confirming the successful preparation of the composite material. The prepared Mg 3 Al-LDH/Ti 3 C 2 -NH 2 was applied as a catalyst in the aldol condensation reaction. Key factors such as catalyst dosage, reaction time, acetone amount, and temperature were investigated to optimize catalytic efficiency. Under optimal conditions—100 mg Mg 3 Al-LDH/Ti 3 C 2 -NH 2 , a reaction time of 0.5 h, 200 mg of p -nitrobenzaldehyde, 1 mL of acetone, and a reaction temperature of 60 °C—a yield of 99% was achieved. The result demonstrates that Mg 3 Al-LDH/Ti 3 C 2 -NH 2 exhibits excellent catalytic activity and holds promising potential for application in solid base catalysis.
研究领域:
材料科学
·
催化化学
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产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2024
·
IF 2.3
Shang Zhihang,Li Zhiqiang,Zhou Xiang,Zhanwang Xingzhou,Nie Lifang,Liu Juncheng
High-hardness hydrophobic anti-reflection thin films were prepared by a mixture of acid-catalyzed and alkali-catalyzed sols using tetraethyl silicate (TEOS) and methyltriethoxysilane (MTES) bisilicon sources as precursors. The alkali-catalyzed SiO 2 sol and the acid-catalyzed SiO 2 sol modified with aliphatic alcohol ethoxylated ether (AEO) were synthesized firstly, and then the acid-catalyzed SiO 2 sol was doped into the alkali-catalyzed SiO 2 sol in a certain ratio to prepare the anti-reflection thin films. The effects of the doping ratio of acid-catalyzed SiO 2 sol on the microstructures and properties of thin films were investigated. The experimental results show that both the transmittance and the contact angle increase and then decrease with the increasing of the doping ratio of acid-catalyzed SiO 2 sol, and the surface hardness and adhesion are gradually enhanced. When the doping ratio of acid-catalyzed SiO 2 sol is 30%, the average transmittance of the reflectance-reducing film is 92.51% in the wavelength range of 400–1100 nm, which is 5.17% higher than that of the blank glass. The water contact angle of the reflectance-reducing film is up to 92°, and the adhesion of the film is the highest level 0. After 100 h of UV exposure, the transmittance of the film was reduced by 1.1%. Graphical
研究领域:
材料科学
·
表面工程
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产品关联
DOI
高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2018
·
IF 6.377
Xing-Xia Yang,Yi-Tong Wang,Ya-Ting Yang,Er-Zhong Feng,Jia Luo,Fan Zhang,Wen-Jing Yang,Gui-Rong Bao
The transesterification activity of several solid base catalysts in biodiesel production was systematically studied and evaluated at room temperature. Commercialized calcined silicates showed stronger transesterification ability than other commonly-used oxides, and provided considerable biodiesel yields. Biodiesel yield of >96% was obtained for Na 2 SiO 3 catalyst (calcined at 400 °C) at 28 °C within 12 h with methanol/oil molar ratio of 12/1 and catalyst dosage of 5 wt%, and for CaSiO 3 catalyst (calcined at 550 °C) at 28 °C within 24 h with methanol/oil molar ratio of 27/1 and catalyst dosage of 23 wt%. The high activity of Na 2 SiO 3 came from low activation energy of 104.6 kJ/mol and considerable higher pre-exponential factor of 3.73 × 10 15 min −1 , which produced high turnover frequency of 0.234 min −1 at 28 °C. The introduction of CA-O-Si structure in CaSiO 3 resulted in high surface basicity of 0.70 mmol/g and high pre-exponential factor of 3.79 × 10 19 min −1 but high activation energy of 136.4 kJ/mol. The loss of catalyst activity was mainly due to the variation of surface silicate structure during transesterification.
研究领域:
化学工程
·
可再生能源
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2021
·
IF 5.161
Yue Zhao,Jun-Bo Xu,Ji-Ming Hu
In this work, a porous silica film pretreatment layer with a thickness up to 8 μm was prepared on the surface of mild steels with the aid of alkaline catalysis. This was achieved by pre-depositing an alkaline film on the substrate before deposition of silica layer. Polymeric resin was then painted on silica film pretreatment layer for long-term protection. Active protection performance was further achieved by loading corrosion inhibitors in the pretreatment layer. Electrochemical impedance spectroscopy and scanning vibrating electrode technique both demonstrate the excellent corrosion performance of the painting system constructed on such a pretreatment layer.
研究领域:
材料科学
·
电化学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SURFACTANTS AND DETERGENTS
·
2019
·Vol. 22
·期 6
·1515-1520
·
IF 1.672
Jiazhi Chen,Yuan Li,Xiaotian Chen,Yuliang Mai,Minjie Gao,Junjie Zhang,Xi Wang
A general and efficient method, involving sand-milling pretreatment and base-catalyzed transesterification of sucrose and fatty acid methyl ester (FAME), was presented for the solvent-free synthesis of sucrose esters. A metastable homogeneous paste with a solid particle size of 13 μm ( D 50 ) was obtained by milling at 1000 rpm for 1 h. This reaction mixture generated a total SE yield of 88.2% with a methyl stearate (MS) conversion of 91.4% using K 2 CO 3 as a catalyst at 135 °C for 3 h at a stirring rate of 500 rpm, while those without milling ( D 50 , 153 μm) yielded a total sucrose fatty acid esters (SE) of 49.3% with a MS conversion of 83.1% under the same reaction conditions. The reaction kinetics revealed that the reaction mixture with milling pretreatment displays a shorter induction time and a faster reaction rate for the formation of SE. The promotion of the solvent-free synthesis of SE in the current study could be attributed to the reduction of solid particle sizes and the increased compatibility of solid–liquid phases. We believe that this strategy could be used as a general way for strengthening other heterogeneous reactions in the organic synthesis.
研究领域:
有机化学
·
食品科学与工程
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产品关联
DOI
高影响因子
APPLIED ENERGY
·
2014
·
IF 5.261
Jinxing Long,Ying Xu,Tiejun Wang,Zhengqiu Yuan,Riyang Shu,Qi Zhang,Longlong Ma
Serious char formation caused by the repolymerization of unsaturated decomposition products is a considerable challenge for current lignin utilization. Here, a novel and efficient base-catalyzed depolymerization and in situ hydrogenolysis process for lignin decomposition and char elimination was proposed using the synergic catalyst of NaOH coordinated with Ru/C. In which, lignin was first depolymerized to phenolic monomer and its oligomer, and then the oligomer was further converted to more stable aliphatic alcohols simultaneously. The results showed that more than 92.5% of lignin was converted, giving 12.69% phenolic monomer, 6.12% aliphatic alcohol and less than 14.03% residual solid. This residual solid selectivity was far lower than it from the single catalyst condition. Furthermore, the products were analyzed using GC–MS, GPC, HPLC–MS and 1 H NMR. The synergistic effect between depolymerization and hydrogenolysis was also investigated through comparative analysis of the feedstock, products, and the recovered lignin.
研究领域:
化学工程
·
生物质能
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）