FUEL
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2024
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IF 6.7
Zhenfeng Sun,Kaiqiang Zhao,Chen Wang,Jie Li,Haisheng Xu,Chao Yang
Presulfiding agents are widely used in oil refining and chemical industry, how to produce safe and efficient presulfiding agent by more environmentally friendly synthesis process are still problems to be solved. In this study, the organic polysulfide FSA-55 was synthesized by a practical one-pot process using isobutene and sulfur as raw materials and organic amine as a catalysts. The product components were analyzed and the possible catalytic reaction pathways in the thermal conversion of sulfides were elucidated. The amine catalysts showed a catalytic activities in inducing the ring opening of the cyclic molecular structure of sulfur at high temperature, thereby releasing the reactive sulfur radicals, which react with unsaturated double bonds through addition reactions. Different molecular structures of polysulfide were generated through molecular rearrangement and cyclization reactions. The suitability of the product as a presulfiding agent was investigated by analyzing the thermal properties and studying the presulfiding effect on hydrogenation catalysts. The polysulfide has a wide decomposition temperature range (100–260 °C), which can effectively avoid the occurrence of concentrated exothermic phenomena during presulfiding of hydrogenation catalysts. The presulfiding degree of the catalysts can reach 58.32%, which shows the great potential of oil processing as a presulfiding agent.
研究领域:
石油化工
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催化化学
✓ 已验证
DOI
高影响因子
Advanced Composites and Hybrid Materials
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2018
·Vol. 2
·期 1
·51-69
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IF 0
Shen Liang,Tian Lian,Zuo Jian,Zhang Xuan,Sun Shipeng,Wang Yan
A desirable membrane with high separation performance, excellent antifouling properties, and chemical stability is important to the advance of forward osmosis (FO) technology in the wastewater treatment and desalination processes. In this work, three different tertiary amines, i.e., tri-ethylamine (TEA), tris(2-aminoethyl) amine (TAEA), and hexamethylenetetramine (HMTA), are employed as catalysts to accelerate the interfacial polymerization (IP) reaction for constructing the PA layer with optimized properties and performance of the resulting membranes. For the first time, the effect of different tertiary amines on the microstructure, morphology, and surface properties of formed PA layers, as well as the separation performance, fouling, and chemical resistance of the resulting TFC membranes, are studied systematically with various characterization techniques. As compared with the control membrane, modified membranes exhibit obviously improved separation performance and greater potential in the desalination process. Furthermore, modified membranes also exhibit improved fouling resistance and chemical stability. Therefore, the tertiary amine modification of TFC membranes may shed a new light for their future applications in harsh conditions.
Graphical abstract
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
Journal of Chemical Information and Modeling
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2024
·
IF 5.6
Xu Li,Haoliang Zhong,Haoyu Yang,Lin Li,Qingji Wang
Nucleophilic index (NNu) as a significant parameter plays a crucial role in screening of amine catalysts. Indeed, the quantity and variety of amines are extensive. However, only limited amines exhibit an NNu value exceeding 4.0 eV, rendering them potential nucleophiles in chemical reactions. To address this issue, we proposed a computational method to quickly identify amines with high NNu values by using Machine Learning (ML) and high-throughput Density Functional Theory (DFT) calculations. Our approach commenced by training ML models and the exploration of Molecular Fingerprint methods as well as the development of quantitative structure–activity relationship (QSAR) models for the well-known amines based on NNu values derived from DFT calculations. Utilizing explainable Shapley Additive Explanation plots, we were able to determine the five critical substructures that significantly impact the NNu values of amine. The aforementioned conclusion can be applied to produce and cultivate 4920 novel hypothetical amines with high NNu values. The QSAR models were employed to predict the NNu values of 259 well-known and 4920 hypothetical amines, resulting in the identification of five novel hypothetical amines with exceptional NNu values (>4.55 eV). The enhanced NNu values of these novel amines were validated by DFT calculations. One novel hypothetical amine, H1, exhibits an unprecedentedly high NNu value of 5.36 eV, surpassing the maximum value (5.35 eV) observed in well-established amines. Our research strategy efficiently accelerates the discovery of the high nucleophilicity of amines using ML predictions, as well as the DFT calculations.
研究领域:
化学信息学
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计算化学
✓ 已验证
DOI
PubMed
高影响因子
Catalysts
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2023
·Vol. 13
·期 5
·799
·
IF 3.9
Tao Wang,Jie Li,Hanwen Yan,Guoliang Zhang,Shifeng Li
Methacrolein (MAL) is an important intermediate extensively used in the manufacture of methyl methacrylate and other materials (polymers and resins). In this study, a series of secondary amines/acids were explored as catalysts for the condensation of formaldehyde and propionaldehyde to prepare MAL. It was found that the structure of the amines and acids directly affected the yield of MAL. The effect of the catalyst was closely related to the nucleophilicity of the amines as well as the steric hindrance effect, while acids also played a role as co-catalysts. Dibutylamine acetate was selected as the catalyst after investigation. The catalytic performance of the system was systematically studied by a series of single-factor experiments, including stirring rate, temperature, reaction time, acid/amine ratio, and the solvent, and the optimized reaction conditions were obtained. In the optimum condition, the yield of MAL was up to 97.3%. Kinetic experiments were performed for the condensation of formaldehyde and propionaldehyde to MAL, and the activation energies, reaction orders, and rate-limiting step of the reaction were determined. The results indicate that the decomposition of the Mannich base is a rate-limiting step.Keywords:methacrolein;aldol condensation;Mannich reaction;kinetics
研究领域:
有机化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
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2015
·Vol. 31
·期 5
·787-791
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IF 0.875
Tang Cen,Jin Yanxia,Wang Xiaoxia,Hu Gengshen,Xie Guanqun,Li Xiaonian,Luo Mengfei
The manufacture of 1,1-dichloroethylene(1,1-DCE) usually employs liquid phase method to perform the dehydrochlorination of 1,1,2-trichloroethane(TCE), where large amounts of high-concentration salty wastewater is produced inevitably. It has been a long-term goal to achieve the gas phase synthesis of 1,1-DCE via supported catalysts. In this work, the gas-phase synthesis of 1,1-DCE from TCE was studied in the presence of pentaethylenehexamine( PEHA) supported on silica. High and stable selectivity to 1,1-DCE(up to 98%) was obtained, which could be ascribed to the relatively strong basicity of PEHA according to a proposed E2 mechanism. The formation of PEHA chloride from the HCl generated in situ was detected and was considered to be the main reason for the deactivation of PEHA catalyst.
研究领域:
化学工程
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催化化学
✓ 已验证
DOI
高影响因子
International Journal of Polymer Science
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2019
·
IF 1.892
Weiping Du,Guiming Zhang,Song Wang,Lianjiang Tan,Huifang Chen
An optical polythiourethane based on m-xylylene diisocyanate (XDI) and 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol (BES) has been studied. Triethylamine was adopted as a catalyst, and the solid-state isothermal cure reaction was carried out using FTIR spectroscopy, in the temperature range of 75°C-105°C. The -NCO absorption band of XDI was used to monitor the conversion of diisocyanate into polythiourethane. The reaction rate enhanced with an increase in the content of the catalyst, and the gel time determined by swelling test was shorter for the system with higher catalyst content. Kinetic parameters were calculated from the infrared spectrum data, and the results showed that the curing reaction of polythiourethane accords with first-order kinetic characteristics. The activation parameters obtained from the evaluation of kinetic data were , , and . The observed negative entropy of activation value supported the formation of a transition state in the cure reaction.
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
Journal of CO2 Utilization
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2023
·
IF 7.7
Qin Wen,Xuexin Yuan,Qiqi Zhou,Hai-Jian Yang,Qingqing Jiang,Juncheng Hu,Cun-Yue Guo
The catalytic fixation of greenhouse gas CO 2 has been a hot topic of research, in which the reduction and functionalization of CO 2 is important for application. In present work, cheap and readily available alkanolamines were used as efficient catalysts with phenylsilanes as reducing agents to achieve the N-formylation reaction by constructing C-N bonds via the reaction between CO 2 and amines (aliphatic or aromatic amines) under mild conditions (40℃and 0.1 MPa). Further studies showed that present catalytic system has wide substrates application. Mono-N-formylated compounds were obtained as main products with good to high yields for all amines. It is worthy noted that for p-aminobenzylamine containing two amino groups as substrate, both amino groups are formylated and N-formylation reaction occurs mainly in aliphatic amine with high electron cloud density. Scale-up research has been performed effectively with high conversion of amine (80%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO 2 is proposed via control experiments and spectra verification. Systematic mechanism studies have revealed that after polarization by polar solvent DMSO, N-methyldiethanolamine activates CO 2 by forming internal salts, which are subsequently reduced by phenylsilanes to formoxysilane intermediates and finally to form N-formylated products.
研究领域:
化学
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环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Haoliang Zhong,Ying Wu,Xu Li,Tongfei Shi
Recently, using well-known data to drive the chemical feature of catalysts for the specified reaction has emerged as a prevalent approach in catalysis science. Amines as essential compounds play crucial roles in living organisms, pharmaceutical, agricultural applications, and various chemical reactions. However, developing a systematic strategy for the screening of amine as an organic catalyst in ring-opening polymerization (ROP) remains a significant challenge. In predicting the catalytic performance of ROP reactions, the proton affinity (PA) of amines as a significant indicator, which reflects the basicity of the catalyst and the activity of the ROP reaction. Herein, we conducted a systematical analysis on a dataset of 259 unique amine compounds, involving the application of seven classical machine learning models and 23 molecular descriptors. The predictive model was constructed with molecular descriptors and DFT-calculated PA values. Among the regression results, the Support Vector Machine (SV) model exhibited the optimal performance, with R 2 , average mean absolute error (MAE) and root mean square error (RMSE) achieving 0.84, 8.38 kJ/mol and 13.77 kJ/mol, respectively. We further employed SHAP (SHapley Additive exPlanations) to evaluate feature significance and provide insights into screening amine catalysts for ROP reaction. The top 10 amines with high PA values are enumerated and discussed. This workflow of coupling machine learning and the DFT approach is an effective way for screening amine catalysts in ROP reaction.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）