Membranes
·
2020
·Vol. 10
·期 1
·12
·
IF 3.094
Xi Yang
The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize nanofiltration (NF) membranes. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies were applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer, and (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in situ Fourier transform infrared (FT-IR) spectroscopy was firstly used to monitor the IP reaction of PIP/TMC with hydrophilic interlayers or macromolecular additives in the aqueous solution of PIP. Moreover, the formed polyamide layer growth on the substrate was studied in a real-time manner. The in situ FT-IR experimental results confirmed that the IP reaction rates were effectively suppressed and that the formed polyamide thickness was reduced from 138 ± 24 nm to 46 ± 2 nm according to TEM observation. Furthermore, an optimized NF membrane with excellent performance was consequently obtained, which included boosted water permeation of about 141–238 (L/m2·h·MPa) and superior salt rejection of Na2SO4> 98.4%.Keywords:interfacial polymerization;in situ FT-IR spectroscopy;thin-film composite membrane;nanofiltration membrane
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Xingrui Yu,Chao Xiong,Yichao Liang,Xiantai Zhou,Can Xue
Epoxides are important bulk chemicals, playing irreplaceable role in the chemical industry, but facing serious pollution and low productivity in the production process. Therefore, the development of green and efficient epoxidation of olefins by stable catalysts with low prices is of great significance. In this study, a Mo-MATP catalyst was prepared by modifying Mo(CO)₆ on attapulgite through Si-O bonding. Mo-MATP exhibits excellent performance (99% yield of cyclooctane oxide, CYCO) and stability (80% selectivity of CYCO after 17 cycles), highly tert -butyl hydroperoxide (TBHP) utilization, and extensive substrate scalability. Furthermore, the in-situ Fourier Transform Infrared Spectroscopy (FT-IR), Electron Spin-resonance Spectroscopy (ESR) and High Resolution Mass Spectrometry (HRMS) spectra suggest that TBHP would be activated by Mo-MATP to generate peroxyl radicals, which then oxidize alkenes to their corresponding epoxides. In this study, the stable loading of Mo would largely solve the problem of Mo loss during the catalytic process, thus providing a stable and dispersed Mo active center, enabling the catalyst to possess high catalytic performance and recycling stability.
研究领域:
催化化学
·
绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CATALYSIS
·
2020
·
IF 7.888
Lei Liu,Xiao-Chao Chen,Shu-Qing Yang,Yin-Qing Yao,Yong Lu,Ye Liu
Formic acid (FA) is one kind of important bulk chemicals, which is recognized as a sustainable and eco-friendly energy carrier to transport H 2 via dehydrogenation or CO via decarbonylation. Expectantly, FA upon decomposition into H 2 and CO could be used as the syngas alternative for hydroformylation. In this paper, the behaviors of FA to release H 2 as well as CO following the distinct pathways were carefully investigated for the first time, and then established a new hydroformylation protocol free of syngas. It was found that the atmospheric hydroformylation of olefins with formic acid (FA) as syngas alternative was smoothly fulfilled over Xantphos ( L1 ) modified Rh-catalyst under mild conditions (80 °C, Rh concentration 1 mol %, 14 h), resulting in >90% conversion of the olefins along with the high selectivity to the target aldehydes (>93%). By using FA as syngas source, the side-reaction of olefin-hydrogenation was greatly depressed. The in situ FT-IR and the high-pressure 1 H NMR spectroscopic analyses were applied to reveal how FA behaves dually as CO surrogate and hydrogen source over L1 -Rh(acac)(CO) 2 catalytic system, based on which the deeply insight into the catalytic mechanism of hydroformylation of olefins with FA as syngas alternative was offered.
研究领域:
催化化学
·
绿色化学
·
能源化学
✓ 已验证
DOI
高影响因子
AICHE JOURNAL
·
2022
·Vol. 69
·期 5
·e17974
·
IF 4.167
Hao Yan,Delun Ren,Zhiqiang Li,Junshu Chen,Xinyang Zhang,Yanhao Wang,Gongzheng Duan,Xiang Feng,Xin Zhou,Yibin Liu,Xiaobo Chen,Chaohe Yang
Engineering acid site spatial location of zeolite catalyst harbors tremendous potential to boost catalytic performance but still remains a grand challenge for aromatization reaction. Herein, we successfully manipulate acid site spatial location inside the ZSM-5 channels to promote the hexane aromatization via the simple SiO 2 coating treatment. Multi-techniques demonstrated that the medium strong L acid in the channel originated from the Si(Al) O Zn structure is mainly retained in the Zn/ZSM-5-Si catalyst by covering the acid sites outside the channel. Surprisingly, there is a good linear relationship between BTEX yield and this medium strong L acid content. Based on the reaction kinetics, in situ FT-IR and theoretical calculations, it is found that the L acid with confinement effect served as the main active site could prominently enhance the cyclization of propene intermediate and the dehydrogenation of cycloalkane due to the strong affinity between the C/H and ZnOx, and control the desorption of BTEX (mainly benzene, toluene, ethylbenzene, and p-xylene) by weakening the binding of hydrogen proton to π electrons. Compared with the ordinary Zn/ZSM-5 catalyst, the yield of BTEX is increased by nearly 10%, and the Zn/ZSM-5-Si catalyst exhibits excellent anti coking deactivation ability. This strategy together with mechanistic results may pave the rational design of efficient Zn/ZSM-5 catalysts for aromatization reaction.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Chengming Wu,Ting Wu,Jifan Li,Chun-Ling Liu,Wen-Sheng Dong
A series of zirconium phosphates (ZrP- x ) with various P/Zr ratios were prepared. Among the catalysts, ZrP-2.5 with a high specific surface area of 410.9 m 2 ·g −1 and abundant mesopores exhibited outstanding catalytic performance in the synthesis of p -xylene (PX) from 2,5-dimethylfuran (DMF) and ethylene. A high PX yield of 89.2% and a productivity of 72.3 mmol PX ·g cat −1 ·h −1 were achieved at 250 °C using a small amount of catalyst. The excellent catalytic performance of ZrP-2.5 was attributed to the synergy between the large quantities of acidic sites with appropriate acid strength distribution, balanced Brønsted and Lewis acidity, and abundant mesopores . In addition, the catalyst had excellent recyclability and stability. In-situ FT-IR spectra of adsorbed DMF and ethylene revealed the crucial roles of P-OH and the coordinately unsaturated Zr(IV) in the adsorption and reaction process, which is beneficial to understanding the reaction mechanism and designing highly efficient catalysts.
研究领域:
催化
·
化学工程
·
材料科学
·
可持续化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Shiyao Lu,Jian Zhang,Hao Meng,Xiaoyuan Qin,Jianbin Huang,Yehao Liang,Feng-Shou Xiao
Dehydration of methyl lactate (ML) obtained from biomass is a sustainable route for the production of methyl acrylate (MA). Herein, we demonstrate that cesium-exchanged Al-rich Beta zeolite (Cs-Beta) is highly efficient for the dehydration of ML to MA, exhibiting full ML conversion with 87.4% MA yield at 340 °C. In situ FT-IR spectra and kinetic studies provide evidence that the ML dehydration on the Cs-Beta zeolite follows a forward ion-exchange/dehydration/reverse ion-exchange reaction pathway. Model experiments, DFT calculations, TG-DSC analysis, and FT-IR spectra showed that coke formation competes with the dehydration of ML to MA. Kinetic studies and theoretical simulations demonstrate that cesium cations in the micropores of Beta zeolite have a strong steric hindrance, suppressing the formation of oligomers and coke. These results offer new insights for developing highly selective and stable catalysts for the dehydration of ML to MA in the future.
研究领域:
化学工程
·
催化
·
材料科学
·
可持续化学
✓ 已验证
产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Xu Liu,Peide An,Yide Han,Hao Meng,Xia Zhang
Cu-based nanozyme shows good oxidase-like activities due to the changeable states of Cu(II) and Cu(I), which are proven to be effective in the electron transfer in the redox process. Herein, the self-made MOF-818 with more Cu(II) loading was synthesized through a modified two-steps hydrothermal routes, which was then used as a sacrificial precursor to construct copper/zirconium composite oxides nanozymes (CN-MOF-818). The pyrolysis temperature was varied to obtain the best enzyme-like activities of the resulting CN-MOF-818. The laccase-like and catecholase-like activities were evaluated by using the oxidation of the mixture of 4-aminoantipyrine (4-AAP) and 2,4-dichlorophenol (2,4-DP), and 3,5-Di- tert -butylcatechol (3,5-DTBC) respectively. The enzyme-like activities were optimized through altering the catalytic conditions, and the corresponding enzyme catalytic kinetics including K m and V max were also determined. The enzyme-like mechanism of the CN-MOF-818 were also discussed based on EPR technique and the in-situ FT-IR analyses. In comparison with the pristine MOF-818 and the other reported Cu-based mimics, the as-prepared CN-MOF-818 exhibits the higher oxidase mimetic activities. These CN-MOF-818 can also be employed to detect the epinephrine with a low detection limit of 1.63 μM.
研究领域:
纳米技术
·
催化
·
分析化学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Wei Sun,Shijie Shao,Jun Pan,Yangyang Wang,Hangqi Xia,Xiaohui Gao,Hao Zhang,Qiguang Dai,Li Wang,Xingyi Wang
Ce-Ti-Zr mixed oxide catalysts prepared by sol-gel method were used in catalytic combustion of CH 2 Cl 2 . The characterization reveals that the incorporation of Ce and Zr into TiO 2 anatase or Ti and Zr into CeO 2 fluorite promotes hydroxyl groups, Lewis acidity and surface oxygen through the formation of Ti-O-Zr, Ti-O-Ce and Ce-O-Zr species. Ce-Ti-Zr catalysts show high activity for CH 2 Cl 2 oxidation with the rate of 5.66 × 10 −3 –6.45 × 10 −3 μmol s −1 m −2 at 250 °C and high stability for 50 h. The substitution of surface oxygen for Cl maintains the availability of Ti-OH and thus promotes Cl removal as HCl, which is verified by a great increase in the stable activity of physically closely contacted mixture of separated CeO 2 and TiO 2 or Ti 9 Zr 1 particles. In situ FT-IR shows that CH 2 Cl 2 interacts with Ti-OH to form -O-CH 2 -O-, which is quickly rearranged into formate. Finally, formate is oxidized with surface oxygen into CO or CO 2 .
研究领域:
催化
·
环境科学
·
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）