NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 10
·4761-4774
·
IF 3.3
Fen Liu,Wenxuan Bai,Zhiping Gu,Jingcong Zhang,Jinxiang Chen,Jiang Yu
The acidic structure in an iron-based ionic liquid (Fe-IL) is significantly affected by the valent variation and solvent effect during the catalytic reaction. However, the magnetic property of Fe-IL limits the utilization of commonly used characterization methods that require a magnetic field for the structural analysis of Fe-IL. Herein, a quantitative pyridine-IR spectrum method was developed by analyzing the slope of straight lines (Slope(X)) in IA(X) ∼ n(Py) relationship graph (IA(X): integrated area of νPyH+ or νPy-L (cm−1); n(Py): the mole of added pyridine (mol)) to determine the structural forms of Brønsted and Lewis acid in Fe-IL, as well as the Lewis activity according to the Beer's law. Different Fe-IL systems, such as Fe-ILaq (from FeCl3·6H2O), Fe-ILnon-aq (from non-aqueous FeCl3) and Fe-ILnon-aq + HCl, were designed and synthesized with similar cationic and anionic structures, in which the Lewis acidity and Lewis activity are significantly influenced by Brønsted acidity. The results showed that the Brønsted acidity in Fe-ILnon-aq is lower than that in Fe-ILaq, and Fe-ILnon-aq can be transferred into Fe-ILaq after protonation. The Slope(L) of FeCl4− has the value of 0.21–0.28 in Fe-ILnon-aq and Fe-ILaq before protonation, and protonation could significantly decrease the value of Slope(L) and Lewis activity, which is mainly caused by the steric hindrance of FeCl4− with the increased amount of the Brønsted acidic structure of Fe–Cl–HCl. In addition, the solvent effect of polyethylene glycol dimethyl ether (NHD), which is a commonly used organic solvent for the absorption of an acidic gas, on the acidic structure and Lewis activity of Fe-IL was also investigated. We found that relatively free HCl that is combined with the Fe–Cl bond in the Fe-ILaq/NHD complex can be predicted by analyzing the slope of IA(X) ∼ n(Py), and the Lewis activity of FeCl4− decreases with increasing volume ratio of NHD. It is confirmed by density functional theory (DFT) calculation that the decreased Lewis activity of Fe-IL caused by the protonation and solvent effect is mainly attributed to the decreased electron-withdrawing ability of FeCl4− and the bond length of the Fe–Cl bond. Furthermore, DFT calculation and CV characterization further demonstrate the reliability of the developed quantitative pyridine-IR method by analyzing the slope of IA(X) ∼ n(Py).
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Jingjing Wang,Xinjie Wei,Zhihui Wen,Junjie Liao,Liping Chang,Jiancheng Wang,Kechang Xie
Ultra-deep desulfurization for the generation of clean petrol, diesel, and benzene remains a significant and challenging goal globally. Cu-containing materials have emerged as a promising desulfurization strategy due to their high adsorption capabilities. However, existing reduction technologies often lead to over-reduction. In this study, we reveal an intriguing and unexpected property of Y zeolite following ammonium ion exchange. The in situ generation of ammonia from ammonia pools may alter the location of copper species and modify their acid characteristics. We encapsulated various amounts of Cu into CuY zeolite, labelled as H-Cu X -Y(APE), using a facile self-reduction strategy. Notably, H-Cu 5.71 -Y(APE) exhibits an exceptional breakthrough sulfur capacity for thiophene, achieving 4.17 mg/g, nearly double that of traditional Cu-HY(H 2 ). XPS analysis following APE reduction indicates a high proportion of Cu + species in H-Cu 5.71 -Y(APE). In situ calcination FT-IR provided detailed insights into the chemical transformation of Cu 2+ species during APE reduction. Furthermore, CO-FTIR analysis shows that the Cu + content in the supercages of H-Cu 5.71 -Y(APE) reaches a maximum of 62.3 %. Py-FT-IR reveals the strong Brønsted acid content in H-Cu X -Y(APE) significantly increases. The desulfurization mechanism of H-Cu X -Y(APE) was thoroughly investigated using in situ FT-IR, demonstrating that the protonation and copolymerization of thiophene occurred on HCuY(APE) and could be effectively suppressed by adjusting the amount of copper. This work presents a promising solution for efficient ultra-deep desulfurization using an in situ NH 3 reduction method from ammonia pools.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 39
·31195-31204
·
IF 3.84
Wen Song,Zhiting Liu,Liping Liu,Anne Ladegaard Skov,Nan Song,Guang Xiong,Kake Zhu,Xinggui Zhou
A route to generate hierarchically porous zeolite ZSM-11 has been paved via solvent evaporation induced self-assembly assisted by hexadecyltrimethoxysilane to produce a preformed dry gel, followed by its subsequent transformation into zeolite via steam-assisted-crystallization. The crystallization in dry gel has been found to undergo an orientated attachment growth mechanism whereby hexadecyltrimethoxysilane directs the formation of auxiliary mesopores and inhibits the fusion of primary nucleates. Measurements such as XRD, SEM, TEM, N2-physisorption, and TEM for an inverse replica of Pt derived from hierarchical ZSM-11 have been conducted to characterize the textural properties of the material. Ammonia temperature-programmed-desorption (NH3-TPD) measurements and infrared spectra using probe molecules such as pyridine (Py-IR) and 2,4,6-collidine (Coll-IR) have been collected to investigate the acidic properties as well as the accessibility of the acid sites. The hierarchical ZSM-11 possesses more acid sites on the mesopore surfaces that are accessible towards large probe molecules such as 2,4,6-collidine. This improvement together with the enhanced pore-connectivity brings about an increase in 1,3,5-triisopropylbenzene cracking activity and benzene selectivity with respect to a conventional counterpart.
研究领域:
材料科学
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化学工程
·
催化
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Shiwei Feng,Chengping Zhang,Hengdao Quan
As an environmentally friendly cleaning agent, Z -1-chloro-3,3,3-trifluoropropene (HCFO-1233zd( Z )) can realize industrial production by the isomerization of HCFO-1233zd( E ). Herein, various isomerization catalysts with different structures, compositions and acid properties were prepared through the fluorination of γ-Al 2 O 3 with CHF 3 by controlling the activation conditions. For the first time, the catalysts for HCFO-1233zd( E ) isomerization were systematically studied by XRD, N 2 physisorption, XPS, SEM, MAS NMR spectroscopy, NH 3 -TPD and py-IR. The active site of this reaction was revealed and the catalyst deactivation mechanism was proposed. It turned out that HCFO-1233zd( E ) isomerization prefers to occur at Lewis acid sites with moderate density and strength. The amorphous particles composed of γ-Al 2 O 3 , Al 2 O 3 (F) and α-AlF 3 ( R 3 ¯ c ) at 450 °C exhibit highly catalytic activity for HCFO-1233zd( E ) isomerization. After 100 h evaluation, it was found that residual γ-Al 2 O 3 can be fluorinated by HCFO-1233zd( E ) to form needle-like structures which could induce the amorphous Al 2 O 3 (F) particles to reorganize and give cubic structures, where the Lewis acid properties were enhanced, leading to catalyst deactivation.
研究领域:
催化
·
化学工程
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2015
·
IF 3.52
Haimei Xu,Zhichao Miao,Huahua Zhao,Jian Yang,Jun Zhao,Huanling Song,Ning Liang,Lingjun Chou
In this paper, a series of ordered mesoporous zirconium oxophosphate with different P/Zr molar ratios (M-ZrPO- x ) were prepared via one-pot evaporation induced self-assembly strategy (EISA). The catalytic performance of M-ZrPO- x for the dehydration reaction of fructose to produce 5-hydroxymethylfurfural (5-HMF) was also studied. With high concentration of Brönsted and Lewis acid sites measured through NH 3 -TPD and pyridine-IR, M-ZrPO-0.75 performed high catalytic activity (up to 97.4%) and selectivity (79.6%) of 5-HMF under relatively mild conditions. Furthermore, M-ZrPO-0.75 performed excellent catalytic stability. Based on detailed analyses of XRD, SEM, TEM, BET and XRF, the structural, surface and textural properties of M-ZrPO-0.75 after reaction were investigated. Obtained results demonstrated that the mesostructure still retained even after twelve cycles, which may be ascribed to the “ordered” mesoporous properties and high thermal stability. In addition, a lower activation energy was obtained in this M-ZrPO catalytic system using dimethyl sulfoxide as solvent.
研究领域:
化学工程
·
催化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2025
·
IF 4.7
Zhang Yanting,Ding Yunlong,Guo Yunya,Wang Wenfeng,Li Xiaofeng,Dou Tao
The development of mesoporogen-free synthetic routes for hierarchical ZSM-5 zeolites is critical to advancing their application in diffusion-constrained catalytic processes such as heavy oil cracking. Here, we develop a mesoporogen-free strategy through synergistic control of seed solution temperature (70-170 °C) and addition amount (0.8-50 wt%). The synthesized zeolites were characterized using techniques such as X-ray Diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), N 2 adsorption-desorption, ammonia temperature-programmed desorption (NH 3 -TPD), and pyridine-infrared (Py-IR). The results show that the sample is rich in mesopores and has well-preserved microporosity. Control experiments under TPAOH conditions equivalent to the seed solution addition amounts and with room-temperature-dried seed solids equivalent to the seed solution were conducted to highlight the critical role of seed solutions. Notably, seed solutions stored for three months retained their effectiveness in synthesizing phase-pure ZSM-5 zeolites, demonstrating exceptional stability. In tetralin (heavy oil model) cracking tests, the optimized zeolite (HZ-T100-A50) achieved 90 % conversion within 2 hours, which is 20 % higher than HZ-T100-A0.8, attributed to enhanced reactant accessibility. This study not only provides an eco-friendly method for synthesizing hierarchical ZSM-5 zeolites without mesoporous templates but also deepens the understanding of seed solution impacts, offering an important basis for optimizing zeolites synthesis and application.
研究领域:
材料科学
·
催化化学
·
化学工程
·
多孔材料
·
石油炼制
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2019
·
IF 4.914
Yaxuan Jing,Yu Xin,Yong Guo,Xiaohui Liu,Yanqin Wang
Aldol condensation is of significant importance for the production of fuel precursors from biomass-derived chemicals and has received increasing attention. Here we report a Nb 2 O 5 catalyst with excellent activity and stability in the aldol condensation of biomass-derived carbonyl molecules. It is found that in the aldol condensation of furfural with 4-heptanone, Nb 2 O 5 has obviously superior activity, which is not only better than that of other common solid acid catalysts (ZrO 2 and Al 2 O 3 ), more importantly, but also better than that of solid base catalysts (MgO, CaO, and magnesium-aluminum hydrotalcite). The detailed characterizations by N 2 sorption/desorption, NH 3 -TPD, Py-FTIR and DRIFTS study of acetone adsorption reveal that Nb 2 O 5 has a strong ability to activate the C=O bond in carbonyl molecules, which helps to generate a metal enolate intermediate and undergo the nucleophilic addition to form a new C–C bond. Furthermore, the applicability of Nb 2 O 5 to aldol condensation is extended to other biomass-derived carbonyl molecules and high yields of target fuel precursors are obtained. Finally, a multifunctional Pd/Nb 2 O 5 catalyst is prepared and successfully used in the one-pot synthesis of liquid alkanes from biomass-derived carbonyl molecules by combining the aldol condensation with the sequential hydrodeoxygenation .
研究领域:
催化
·
化学工程
·
可再生能源
·
有机化学
✓ 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）