DALTON TRANSACTIONS
·
2024
·
IF 3.5
Zhengyan Wang,Chenhao Yuan,Dong Yang,Mifen Cui,Jihai Tang,Zhuxiu Zhang,Xu Qiao
It is of great significance to develop catalysts for the degradation of hexachlorobenzene from the industrial thermal process. In this paper, formic acid was used as a modulator to generate defect sites in Ce/Zr-UiO-66 with intrinsic Brønsted acidity. The defective formate ligands were removed through methanol–water vapor treatment to expose additional open metal sites with Lewis acidity. The intrinsic Brønsted acid sites of the resulting Ce/Zr-UiO-66-FA-P achieved a hexachlorobenzene degradation efficiency of 99.5% at 250 °C. The generated Lewis acid sites facilitated the C–C cleavage of degradation intermediates. More than 95.0% of the final products were CO2/CO, coupled with chlorinated alkanes/alkenes, which outperformed other benchmark metal oxide catalysts. The Ce/Zr-UiO-66-FA-P catalyst maintained its catalytic activity in the model industrial flue gas and humid environment. The degradation pathway of hexachlorobenzene was tracked using in situ FT-IR spectra.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemSusChem
·
2019
·Vol. 12
·期 22
·4927-4935
·
IF 7.804
Xiao-ling Qu,Min Jiang,Bing Wang,Jin Deng,Rui Wang,Qiang Zhang,Guang-yuan Zhou,Jun Tang
Graphical Low loading : With a small catalyst loading of metal-free and selective ionic liquids (0.1 % based on 2,5-furandicarboxylic acid), bioderived poly(ethylene 2,5-furandicarboxylate) is efficiently prepared with high molecular weight by the electrophilic activation induced by hydrogen bonds, which are formed between the ionic liquid [C 2 MIM] + and the carbonyl oxygen. Green synthesis of bioderived high-molecular-weight poly(ethylene 2,5-furandicarboxylate) (PEF) over metal-free catalysts is a significant challenge. This study focuses on PEF prepared from ethylene glycol and 2,5-furandicarboxylic acid (FDCA) through a direct esterification method with ecofriendly metal-free ionic liquids (ILs) as catalysts. The catalytic activities of a series of imidazolium cations in the presence of various anions are systematically investigated and found to be mainly governed by the anions. Among the ILs studied, 1-ethyl-3-methylimidazolium tetrafluoroborate ([C 2 MIM]BF 4 ) is identified as the best catalyst, showing excellent catalytic activity, selectivity, and stability, even at low catalyst loadings (0.1 mol % w.r.t. FDCA). Optimization of the polymerization parameters enables [C 2 MIM]BF 4 -catalyzed production of PEF with a high number-average molecular weight ( M n =5.25×10 4 g mol −1 ). The relationship between Brønsted acidity and catalytic activity is also investigated and the results show that the trend in catalytic activity is in good agreement with that in Brønsted acidity, as determined by the Hammett method. Additionally, on the basis of experimental results and density functional theory calculations, an electrophilic activation mechanism induced by hydrogen bonds is proposed. This strategy of adjustable acidity and anion structure in ILs provides an opportunity to develop other ILs for bio-based polyesters through green synthesis pathways.
研究领域:
化学工程
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材料科学
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绿色化学
✓ 已验证
DOI
高影响因子
TETRAHEDRON LETTERS
·
2022
·
IF 2.032
Xiangshan Li,Shihao Liu,Yao Chen,Guangxu Zhang
A novel Brønsted acidic heteropolyanion-based ionic liquid (IL) ([MIMPS] 3 PW 12 O 40 ) was synthesized and employed to catalyze the Baeyer-Villiger (BV) reaction to produce ε-Caprolactone (ε-CL). Noteblely, the prepared IL catalyst exhibited higher catalytic activity compared to solid acid catalysts duo to its behavior of reaction-induced self-separation. It meaned that the IL catalyst could switch from solid to liquid, then back to solid state during the reaction, which broke the limit of the constant heterogeneous state of the catalyst in the reaction system. The characterization results of FT-IR, 1 H NMR, XRD, and XPS indicated that the phosphotungstic anion (PW 12 O 40 3- ) was successfully modified by the organic precursor MIMPS . And TG-DTA and Py-IR results illustrated that the catalyst possessed good thermal stability and Brønsted acidity. Furthermore, the activity evaluation experiment of the catalyst confirmed that the introduced SO 3 H group of the cation part and the active component tungsten of the anion part were the key to the activity of the IL catalyst. More importantly, the synergistic effect between SO 3 H group and the active component tungstencatalyst leading to a superior catalytic performance such as cyclohexanone conversion attained 93.51 % and the yield and selectivity of ε-CL that were up to 93.26 % and 99.73 % under the optimum conditions. Finally, the kinetic process of the BV reaction was appropriately described by the second-order reversible reaction kinetics model and the calculated results were also in good agreement with the experimental datas.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
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2014
·Vol. 4
·期 43
·22520-22525
·
IF 3.708
Yong Liu,Yi-Tao Wang,Tao Liu,Duan-Jian Tao
SO3H-functionalized Brønsted acidic ionic liquids (BAILs) were synthesized and utilized as highly efficient catalysts for the production of fructone via the acetalization reaction of ethyl acetoacetate with ethylene glycol. In comparison with conventional H2SO4 and cation exchange resins, the BAILs N-(4-sulfonic acid) butyl triethylammonium hydrogensulfate ([BSEt3N][HSO4]) of strong acidities exhibited excellent catalytic activities. The effects of various parameters such as different BAILs, reaction temperature, catalyst dosage, and molar ratio of the reactants on the conversion of ethyl acetoacetate were investigated in detail. The experimental results indicated that the catalytic performance of BAILs were closely related to their Hammett acidities. Moreover, it was found that [BSEt3N][HSO4] could be also recovered easily and used repetitively six times without obvious decline in activity and quantity, showing great potential application in industry.
研究领域:
化学工程
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2022
·
IF 5.876
Yanghuan Huang,Haocheng Zhang,Lou Gao,Tianlan Yan,Yueer Yan,Yahong Zhang,Yi Tang
A series of Zr–Al-MWW zeolites with different Zr state and layer-stacking structure are successfully synthesized via direct grafting zirconocene dichloride onto the external silanols of three kinds of MWW zeolites, i.e. MCM-22 with multilayered structure, ITQ-2 (through layer delaminated route) and OL-MWW (by direct hydrothermal synthesis) with oligolayered structure. The structure, porosity and state of grafted Zr species are distinctly different among the three Zr–Al-MWW zeolites. Zr-OL-MWW possesses the highest content of single Zr atoms with an ideal micro-meso-macro pore system, while Zr-MCM-22 and Zr-ITQ-2 contain two kinds of Zr species (ZrO 2 clusters and single Zr atoms) coexisting in various proportions. The high dispersion of single Zr atoms on OL-MWW can be assigned to the large amount of external silanols of OL-MWW. The as-prepared three bi-functional Zr–Al-MWW zeolites are used for the cascade Meerwein-Ponndorf-Verley (MPV) reduction and etherification (ETH) reaction. Among them, Zr-OL-MWW shows dramatically higher conversion of cinnamaldehyde and yield of 1-cinnamyl 2-propyl ether than Zr-MCM-22 and Zr-ITQ-2, owing to the higher catalytic activity of Lewis acid centers from single Zr atoms, as well as more integrated framework Al sites as Brønsted acid centers with good accessibility. This study offers a simple and efficient strategy to construct Lewis-Brønsted acidic zeolites with exposed heteroatom sites and integrated framework structure, which will provide especial potential in the catalytic conversion of macromolecules.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2015
·
IF 4.642
Yunlei Zhang,Jianming Pan,Yating Shen,Weidong Shi,Chunbo Liu,Longbao Yu
Employing renewable and widely available feedstock of cellulose as a raw material for 5-hydroxymethylfurfural (HMF) production opens up the possibility of sustainable biorefinery schemes that do not compete with the food supply. In this work, novel and efficient Brønsted acidic polymer nanotubes were successfully prepared by chemical conjugating grafting −SO3H groups onto the surface of polydivinylbenzene (PDVB) nanotubes, which were derived from cationic polymerization of divinylbenzene. By simply adjusting the grafting amounts of hydrophilic −SO3H groups, catalysts with varied hydrophobic and hydrophilic surface wettability (i.e., catalyst-110° and catalyst-10°) could be obtained. It was demonstrated that as-prepared catalyst-10° possessed the higher strong (143 μmol g–1), very strong (614 μmol g–1), and total acidity (786 μmol g–1) than those of catalyst-110°. Besides, the catalytic performance of the synthesized catalyst-110° and catalyst-10° were investigated and compared for the conversion of cellulose to HMF in an ionic liquid (i.e., 1-ethyl-3-methyl-imidazolium chloride, [EMIM]-Cl) system. Particularly, catalyst-110° exhibited the highest HMF yield of 34.6% on a molar basis, which was comparable with that of catalyst-10° (i.e., 37.1%), indicating that its hydrophobic nature was beneficial for decreasing side-reaction of HMF which tend to convert to some other byproducts during the very one-pot reaction. Furthermore, both catalysts can be easily recovered and reused for at least four times without significant loss of their catalytic activities. This work was the continue efforts for fabrication and application solid catalyst for excellent conversion of one-pot cellulose to HMF.
研究领域:
化学工程
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材料科学
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可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2014
·Vol. 16
·期 4
·2234-2241
·
IF 6.852
Qiaohong Peng,Khalid Mahmood,Ying Wu,Leli Wang,Yanyan Liang,Jianan Shen,Zhengping Liu
Biodegradable copolymers of L-lactic acid and ε-caprolactone [P(LLA-CL)s] were prepared in sulfonic acid-functionalized Brønsted acidic ionic liquids (SFBAILs) with very different anions and cations. SFBAILs work as both solvents and catalysts. The copolymerization process was proved to be a combination of polycondensation and simultaneous transesterification after a fast ring-opening polymerization of ε-caprolactone through a kinetic study. Copolymers with different monomer ratios were obtained. We found that the anions rather than the cations of SFBAILs have a great impact on the polymerizations. In addition, SFBAILs can be simply recovered by phase separation and recycled without decreasing the efficiency.
研究领域:
高分子化学
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材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
BIOMASS & BIOENERGY
·
2017
·
IF 3.219
Haian Xia,Hong Hu,Siquan Xu,Kehao Xiao,Songlin Zuo
A series of Fe/β zeolite catalysts with various Fe/Al ratios were prepared by liquid ion-exchanged method and were characterized by N 2 adsorption, XRD , UV–Vis DRS, EPR , NH 3 -TPD, and FTIR of pyridine adsorption techniques. The catalysts were used to catalyze the transformation of glucose into 5-hydorxymethyfural (HMF) in a biphasic reaction system under mild reaction conditions. The Fe/β catalysts with Lewis acidic Fe sites is able to effectively improve the HMF yield compared to H-β zeolite under identical reaction conditions, which is ascribed to the enhanced isomerization activity of glucose-to-fructose by Lewis acidic Fe species. Moreover, the Fe/Al ratio had a remarkable impact on the conversion of glucose and the yield of HMF, indicating that the synergetic effect of Lewis and Brønsted acid sites is critical to achieving high HMF yield. Under optimal reaction conditions, Fe/β-0.06 catalyst afforded 61% HMF yield at glucose conversion of 95% after the reaction of 90 min at 120 °C, which is one of the most effective catalysts for the conversion of glucose into HMF in a biphasic medium up to now. Furthermore, extra-framework isolated Fe species bound to the framework Al sites, are most likely the active sites for the isomerization of glucose-to-fructose in the conversion of glucose. The catalysts were very stable and could be reused at least five runs without significant loss in the catalytic activity .
研究领域:
催化化学
·
生物质转化
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2025
·Vol. 30
·期 16
·3319
·
IF 4.6
Tong Chang,Renhui Deng,Jiaxin Xie,Jianyu Tang,Wenyao Gu,Zimin Peng,Suyao Liu
The abundant Si-OH groups serving as the defect sites in the ZSM-22 zeolite framework are not only closely associated with physicochemical properties and catalytic performance but are also the primary sites for attack by water molecules, thereby restricting applications involving or producing water. In the present study, a liquid-mediated healing process was used to convert the Si-OH groups in ZSM-22 zeolite into Si-O-Si bonds. The systematic investigation of the treatment solution’s composition and the hydrothermal conditions revealed that the crystallinity of ZSM-22 zeolite can be effectively enhanced following optimal healing treatment. Furthermore, the healed ZSM-22 zeolite exhibited enhanced ordering degree and pore connectivity without significant changes to the Si/Al and morphology. Moreover, the decline in Si-OH groups reduced the Lewis acid sites without altering the Brønsted acidity, which led to a slight decrease in the dispersion of Pt particles. In n-decane hydroisomerization, compared to the parent ZSM-22 zeolite catalyst, the healed catalyst demonstrates higher reactant conversion and increased isomer yield, attributing to its enhanced confinement within the micropore voids, which leads to a reduced yield of multi-branched isomers susceptible to cracking. This study presents a potential application of ZSM-22 zeolite in hydroisomerization for complex and challenging feedstocks.
研究领域:
催化化学
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材料科学
·
化学工程
·
石油化工
·
沸石化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）