Catalysts
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2021
·Vol. 12
·期 1
·42
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IF 4.146
Longxin Ju,Gang Li,Hongxian Luo
Aldol condensation reactions are very important C–C coupling reactions in organic chemistry. In this study, the catalytic performance of layered double hydroxides (LDHs) in the aldol condensation reaction of formaldehyde (FA) and propionaldehyde (PA) was investigated. The MxAl-LDHs (denoted as re-MxAl–LDHs; M = Ca and Mg; X = 2–4), as heterogeneous basic catalysts toward the aldol condensation reaction, were prepared via a two-step procedure. The catalyst exhibited a high PA conversion (82.59%), but the methacrolein (MAL) selectivity was only 36.01% due to the limitation of the alkali-catalyzed mechanism. On this basis, the direct intercalation of L-proline into LDHs also has been investigated. The influences of several operating conditions, including the temperature, reaction time, and substrate content, on the reaction results were systematically studied, and the optimized reaction conditions were obtained. The optimized Mg3Al–Pro-LDHs catalyst exhibited a much higher MAL selectivity than those of re-MgxAl–LDHs.Keywords:layered double hydroxides;L-proline;aldol condensation reaction
研究领域:
有机化学
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催化材料科学
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DOI
高影响因子
KEY ENGINEERING MATERIALS
·
2019
·
IF 0
Yan Kai Huang,Qi Lin Mei,Zhi Xiong Huang,Yan Qin,Di Zhu
In this paper, the structure of the photosensitive diamines was designed and the method of synthesizing such diamines was investigated. The 1-(3-aminophenyl)-3-(4-aminophenyl)-2-propen-1-one analyzed by elemental analysis and infrared analysis was synthesized through two-step experiments with Aldol condensation and Nitroammoniation process. Through the experiment the optimum reaction conditions are raw material ratio of 1:1, anhydrous ethanol dosage of 60 ml, 10 % NaOH dosage of 10 ml and reaction temperature of 25°C for 4h. The yield was about 55.4 %.
研究领域:
有机化学
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材料科学
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产品关联
DOI
Polymers
·
2023
·Vol. 15
·期 4
·996
·
IF 5
Lizhen Huang,Wenchang Sun,Li Shuai,Xiaolin Luo,Jing Liu
Plywood is made of wood veneers that are bonded with adhesives such as urea-formaldehyde, phenol-formaldehyde and melamine-formaldehyde resins. The plywood made from formaldehyde-based adhesives not only releases formaldehyde but also relies on fossil resources. In this article, we synthesized furan-acetone adducts from lignocellulosic biomass in one pot. The furan-acetone adducts could be directly used as adhesives with the addition of phosphoric acid as a curing catalyst. Particularly, with the addition of 5 wt% diphenylmethane diisocyanate (MDI) as a crosslinking agent, both the wet and dry bonding strength of the plywood prepared from the adhesives could meet the minimum requirement of 0.7 MPa (Chinese National Standard GB/T 9846-2015). The possible adhesion mechanism is that the penetration of furan-acetone adhesives into vessels and cell lumens followed by crosslinking during hot-pressing forms mechanical interlocking at the interface of wood veneers, which provides the main bonding strength of plywood. The findings presented here could provide a new way for the efficient preparation of aldehyde-free green wood adhesives and the value-added utilization of woody biomass.Keywords:bio-based wood adhesives;aldol condensation;bonding strength;furan-acetone adducts;plywood
研究领域:
林业工程
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生物质化学与工程
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DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Yuxia Li,Tingting Ge,Yuchao Li,Yanxia Zheng,Xiaobin Wang,Hui Guo,Zehao Jing,Jian Song,Xinpeng Guo,Ming Wang,Haofei Huang,Cuncun Zuo,Liping Zhang
High-performance MOR zeolite membranes were prepared by loading hydrophilic metal oxides onto the surface of α-Al 2 O 3 support via secondary hydrothermal synthesis method. The effects on the surface morphology and hydrophilicity of MOR zeolite membranes were discussed by means of different metal oxides (TiO 2 , V 2 O 5 , CeO 2 , ZrO 2 , WO 3 ) and loadings in combination with SEM, XRD, Raman and Water Contact Angle (WCA) characterization. TiO 2 -MOR zeolite composite membranes were found that TiO 2 could increase interface hydrophilicity. The pervaporation performances of TiO 2 -MOR zeolite membranes at different temperatures and feed concentrations were investigated. The mass transfer model combining Maxwell-Stefan mechanism, Kundsen diffusion and viscous flow was used to describe the mass transfer process of water molecules through the zeolite layer, and within the α-Al 2 O 3 scaffolds, respectively. The permeation fluxes of water molecules of TiO 2 -MOR zeolite membranes with the loading of 2 wt% were 0.91 kg m −2 h −1 , 1.00 kg m −2 h −1 and the separation factors were up to 10000 at 348 K with 90 wt% AcOH/H 2 O and 90 wt% AA/H 2 O solutions. TiO 2 -MOR zeolite membranes with well acid resistance and high hydrophilicity had promising prospects in the reaction scene where carboxylic acid and water exist simultaneously, such as esterification, ester hydrolysis, acetic acid aldol condensation, etc.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 6
·1797-1806
·
IF 2.936
Wang Yajuan,Liu Wenqiang,Zhang Juan,Shan Qingwen
A novel ionic porous organic polymers catalysts were prepared and characterized by scanning electron microscopy, Brunner − Emmet − Teller measurements, fourier transform infrared spectroscopy and thermogravimetric analysis The characterization results showed that the synthesized catalyst was a porous polymer and had good heat stability. The catalytic performance of the catalyst was evaluated by synthesis of methacrolein from formaldehyde and propionaldehyde. The optimal reaction conditions were: the catalyst amount was 10%(wt%)of propionic aldehyde mass, the reaction temperature was 85 ℃, the reaction time was 1.5 h, the ratio of propionaldehyde and formaldehyde was 1:1.2. Under optimal condition, the conversion rate of propionaldehyde was up to 99.57% and the selectivity of methacrolein was 98.77%. The catalytic activity did not reduced obviously after being reused for 5 times. The reaction kinetics of synthesis of methacrolein was further studied. The results showed that the reaction order was 1.6, the activation energy was 50.28 kJ/mol and the pre-exponential factor was 4.17 × 10 7 (mol/L) −1.456 /s. Graphical Abstract
研究领域:
材料化学
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催化化学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
·
IF 7.632
Yunyun Liu,Yanyan Wang,Yunqi Cao,Xiaoyan Chen,Qiang Yu,Zhongming Wang,Zhenhong Yuan
The incompatibility of the aldol condensation reaction of furfural (FF) and upstream FF conversion limits the direct production of cyclic biofuel intermediates (C10, C15) from lignocellulosic biomass. Herein, an efficient catalytic system comprised of choline chloride–formic acid–SnCl4·5H2O (ChCl-Fa-SnCl4) has been developed, which gives high intermediate yields of 92.03, 88.24, and 56.78%, respectively, from the one-pot conversion of FF xylose and corncob with cyclopentanone (CPO). These data are higher than the reported intermediate recovery of 61.55% observed using FF/CPO and a solid acid catalyst (Nafion resin) under solvent-free conditions and 44% using xylose/acetone and CrCl3/VCl3/[BMIM]Cl. Moreover, Sn(IV) and H+ ions in ChCl-Fa-SnCl4 contribute toward catalyzing the aldol condensation reaction, and far-infrared spectroscopy indicated that deep eutectic solvents may strengthen the coordination of Sn(IV) to the carbonyl group.
研究领域:
化学工程
·
生物化学
·
可再生能源
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Mingxin Lv,Qianghua Xin,Defu Yin,Zhen Jia,Chunyan Yu,Teng Wang,Shitao Yu,Shiwei Liu,Lu Li,Yue Liu
The use of cellulose instead of oil to produce 1,2-propylene glycol (1,2-PG) is of great significance for building a sustainable world. Herein, we synthesize Fe3O4@SiO2/Ru-WOx core–shell magnetically recoverable catalysts containing both Lewis acid and metal active sites using well-shaped Fe3O4@SiO2 core–shell magnetic nanospheres as the substrate. We investigated the catalytic performances of the bimetallic catalysts with various metals as well as different metal contents and WOx loadings for the conversion of cellulose to 1,2-PG. The results showed that Fe3O4@SiO2/10%Ru-20%WOx was more favorable for 1,2-PG production, with a 1,2-PG selectivity of 32.4% and a cellulose conversion of 96.8%. Our characterization and activity tests suggested that WOx on the Fe3O4@SiO2 nanospheres produced abundant Lewis acid sites to effectively promote glucose isomerization to fructose before glucose undergoes the retro-aldol condensation reaction. Moreover, the Ru further hydrogenated the C3 intermediate to 1,2-PG. It was notable that the catalyst can be separated through a simple magnetic separation after the end of the reaction, and it still maintained high catalytic activity after 5 uses.
研究领域:
化学工程
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催化
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可持续化学
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材料科学
✓ 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）