CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Kui Jin,Meiyun Zhang,Penghua Che,Dongru Sun,Yong Wang,Hong Ma,Qiaohong Zhang,Chen Chen,Jie Xu
ABSTRACT Hydrogen bonding is a fascinating interaction that controls the outcomes of chemical reactions. However, overcoming the strong deactivation arising from alterations in the polarity and electronic properties of the reactants and intermediates remains a challenge. Herein, we proposed a “solvent-scissors” strategy for overcoming the inert hydrogen bonding, enabling the efficient aerobic oxidation of methyl aromatics into aromatic acids under atmospheric oxygen at 25–45 °C. The hydrogen bonds between the key intermediate, benzaldehyde (PhCHO), and hexafluoroisopropanol (HFIP) were reconstructed using solvent-scissors (acetic acid (HOAc), ethyl acetate, ethyl chloroacetate , and methyl chloroacetate), which promoted the release of free PhCHO from its inert hydrogen-bonded state and enabled the one-step oxidation of toluene to benzoic acid under mild conditions. The standard Gibbs free energy changes (Δ G 0 ) representing the proton acceptance capability of the solvent were of the same order of magnitude as the turnover number (TON) (capacity for promoting benzaldehyde oxidation). This approach affords remarkable benzoic acid selectivity (98.7%) with high toluene conversion (96.8%) at 45 °C within 4 h under 0.1 MPa O 2 using NHPI/metal acetate/HFIP-HOAc. This strategy opens up a new avenue for regulating hydrogen bonding in a wider range of applications for the planning and development of synthesis protocols.
研究领域:
有机化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Da Sheng,Qing He,Zhong-Hua Cao,Lun-Bo Chen,Song-Hai Wu,Yong Liu,Hai-Tao Ren,Xu Han
Although photooxidation of benzyl alcohol to benzaldehyde in aqueous solution is an important chemical process, its selectivity cannot be readily controlled due to the overoxidation of benzaldehyde. In this study, a series of Bi–Mo/CN photocatalysts are synthesized, and their reactivity in photooxidation of benzyl alcohol under visible light is compared. Bi–Mo/CN-2 exhibits high photocatalytic reactivity in the conversion of benzyl alcohol (51%) with a high selectivity toward benzaldehyde of 99.9%. In this process, the formed ≡Bi–OO• and ≡Bi–OOH selectively oxidize benzyl alcohol to benzaldehyde via the H-abstraction pathway after O2 is photoreduced on Bi–Mo/CN, accompanied by the formation of H2O2. Meanwhile, the doped Mo utilizes the produced H2O2 or ≡Bi–OOH to produce ≡Mo–O2 peroxo, which not only contributes to the selective oxidation of benzyl alcohol to benzaldehyde but also effectively prevents overoxidation of benzaldehyde. This work provides new insight into designing novel photocatalysts for selective oxidation of organic substrates.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2017
·
IF 1.174
Jianhua Chen,Xue Sun,Lijing Lin,Xinfei Dong,Yasan He
In the present paper, a metal–organic framework Cr-BDC was prepared and used as adsorbent for adsorption of o -nitrophenol (ONP) and p -nitrophenol (PNP) from aqueous solutions. Cr-BDC was characterized by scanning electron microscopy, transmission electron microscope, X-ray diffraction and BET methods. The results indicate that Cr-BDC gets a very large specific surface area of 4128 m 2 ·g − 1 and pore sizes are concentrated in 1 nm, which is a benefit for using for wastewater treatment . The influences of the adsorption conditions, such as temperature, solution concentration, adsorption time and reusability on adsorption performance were investigated. Cr-BDC exhibited an encouraging uptake capacity of 310.0 mg·g − 1 for ONP, and adsorption capacity of Cr-BDC for ONP is significantly higher than that for PNP under suitable adsorption conditions. The characterizations of adsorption process were examined with the Lagergren pseudo-first-order, the pseudo-second-order kinetic model, and the intra-particular diffusion model. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. The results indicate that the as-prepared Cr-BDC is promising for use as an effective and economical adsorbent for ONP removal.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2018
·Vol. 96
·期 11
·2443-2449
·
IF 1.265
Jiaming Xue,Zuoxiang Zeng,Weilan Xue,Huayu Yang
The kinetics of the esterification between benzoic acid and isoamyl alcohol has been studied using p -toluenesulphonic acid as a catalyst. The conversion of the benzoic acid was determined by following the concentration of water measured with a Karl Fischer titrator. The effects of the reaction temperature, catalyst concentration, and initial acid to alcohol molar ratio on reaction kinetics have been examined. A five-step assumption was proposed to describe the reaction mechanism for the formation of isoamyl benzoate. And the kinetic model derived from the proposed mechanism can fit well with experimental kinetic data of the esterification, which indicates that the proposed mechanism is reasonable. The nonideality of the liquid reaction mixture has been considered and the activity coefficients of all components were estimated by the UNIFAC model. The reaction rate constants from 353.15 K to 383.15 K have been determined through the least square method. Meanwhile the activation energy and the standard enthalpy change of reaction in the presence of p -toluenesulphonic acid were calculated to be 50.45 kJ/mol and −3.75 kJ/mol respectively.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2017
·
IF 0
Shenghui Zhou,Kuiyi You,Hongxu Gao,Renjie Deng,Fangfang Zhao,Pingle Liu,Qiuhong Ai,He’an Luo
Mesoporous silica-immobilized FeCl 3 (FeCl 3 -SiO 2 ) as a highly efficient and reusable catalyst for the nitration of benzene with NO 2 has been successfully prepared in this work. The physical-chemical properties of samples were characterized by BET, XRD, TG-DTG, NH 3 -TPD, FT-IR, UV–vis DRS, Raman spectra and SEM. The characterization results indicated that FeCl 3 could be immobilized on the silica surface by bonding of FeCl 3 and silicon hydroxyl groups (Si OH) in forming the new Lewis acid sites of Si O Fe Cl 2 . The results showed the immobilized 15%FeCl 3 -SiO 2 catalyst exhibited excellent catalytic performance (99% of benzene conversion with 99% of selectivity to nitrobenzene) under the optimized reaction conditions. Furthermore, the durability of catalyst was remarkably improved by immobilizing. The present immobilized FeCl 3 -SiO 2 catalyst as a solid heterogeneous and stable catalyst could be conveniently recycled from the reaction media by filtering and remained highly catalytic performance even after five runs of recycling. The possible reaction pathway for the nitration of benzene with NO 2 over FeCl 3 -SiO 2 catalyst was suggested. This method provides a promising strategy for highly efficient preparation of nitro aromatic compounds by using NO 2 as nitration reagent, with the potential industrial applications.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
SEPARATION AND PURIFICATION TECHNOLOGY
·
2016
·
IF 3.299
Xiaodan Zhao,Jun Ma,Jin Jiang,Yuhuan Bao,Huiling Liu
Synergistic enhancement of phenols and anilines removal was investigated in permanganate oxidation in the presence of multi-walled carbon nanotubes (CNTs). Then the attendant dehalogenation was explored for bromophenols and bromoanilines from the perspective of dehalogenation number (DN). Permanganate decay and total manganese concentration decrease in the presence of CNTs indicates considerable formation of manganese dioxide (MnO 2 ) on carbon surface. The CNTs-enhanced phenol degradation is more favorable under lower pH, confirming that the generation of MnO 2 induced by the reaction between permanganate and CNTs enhances the phenol oxidation by permanganate. The first order rate constants of respective bromophenols and bromoanilines suggest the synergistic enhancement of CNTs and permanganate in removing these micropollutants. Bromide release experiments clearly demonstrate that the subsequent dehalogenation accompanying the oxidation of bromophenols and bromoanilines is significant for permanganate oxidation in the absence/presence of CNTs. Dehalogenation by permanganate follows the order of 4-bromophenol > 2-bromophenol > 3-bromophenol and 4-bromoaniline > 2-bromoaniline > 3-bromoaniline, respectively. Higher DN values in the presence of CNTs indicate a reduced dehalogenation. In real water application, permanganate in the presence of CNTs could effectively remove 4-bromoaniline with a maximum removal efficiency of ∼95% and a bromide release of 2 μM.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
·
2015
·
IF 2.131
Yuancai Lv,Lianghao Li,Yuancai Chen,Zhenghua Tang,Yongyou Hu
Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a tremendous challenge owing to their extreme persistence and recalcitrance. In this study, Pseudomonas putida was employed for bioremediation of four PBDE congeners (BDE47, 15, 3 and diphenyl ether (DE)) with an initial concentration of 2 mg/L and the cometabolism of PBDEs was illustrated via kinetics analysis and metabolic mechanism. The biodegradation kinetics analysis suggested that PBDEs was inversely proportional to the number of bromine substituted on diphenyl ether. Both glucose (24 mg/L) and biphenyl (10 mg/L) played a positive role in promoting the biodegradation of PBDEs. The growth kinetics analysis indicated that glucose had uncompetitive inhibition on PBDEs consumption while both competitive and uncompetitive inhibition existed in biphenyl-PBDEs binary substrate system. Furthermore, the intermediates were identified by GC–MS and the main tentative degradation pathways were proposed. The angular dioxygenation was the main pathway for PBDEs degradation, while lateral dioxygenation could be induced when biphenyl was added.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
Solar RRL
·
2022
·Vol. 6
·期 8
·2200279
·
IF 9.173
Jie Deng,Wanying Lei,Junwei Fu,Huile Jin,Quanlong Xu,Shun Wang
Herein, photocatalytic selective oxidation of hydrocarbons through O 2 represents a promising way for fine chemical industry on account of its mild reaction condition. In this work, Co 3 O 4 -modified BiOBr/AgBr S-scheme heterojunction can effectively oxidize sp 3 C H bonds at benzylic position to its corresponding aldehydes, with a toluene to benzaldehyde selectivity of 94%, which is much higher than that of pure BiOBr (21.7%) and AgBr (58.9%). A unique S-scheme charge-transfer mode is confirmed for the ternary composites by the X-ray photoelectron spectroscopy and reactive species quenching measurement. The remaining photogenerated electrons in AgBr with powerful reduction ability can react with O 2 to generate •O 2 − species, which can further oxidize the benzyl radical formed on the Co 3 O 4 surface to peroxyl radicals and then thermodynamically decompose to benzaldehyde. Herein, this work has important guiding significance for the structure regulation of photocatalysts and application in selective oxidation of sp 3 C H bond of hydrocarbons.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2021
·
IF 6.953
Kongyou Wu,Kungang Chai,Liqin Zhou,Zhiliang Duan,Haibo Wu,Zhenghui Huang,Dongli Li,Zhongwei Tan,Fang Shen,Zongwu Wei,Hongbing Ji
Herein, a TEMPO-oxidized cellulose-grafted-polystyrene hypercrosslinked polymer (TOC-PS-HCP) was synthesized facilely by TEMPO oxidation , grafting copolymerization and post crosslinking route. Based on the structural characterization, it was confirmed that TOC-PS-HCP mainly consisted of polystyrene chain on cellulose and rigid crosslinked bridge. Additionally, the as-prepared TOC-PS-HCP displayed appropriate hydrophobicity (water contact angle = 102.44°) and high specific surface area (S BET = 601.20 m 2 ·g ‐ −1 ), which could efficiently recover ethylbenzene and styrene from PO/SM wastewater. The adsorption experiment was conducted to study the recovery performance for ethylbenzene and styrene in the aqueous phase. The results showed that TOC-PS-HCP could recover ethylbenzene and styrene quickly by adsorption process, and maintain a stable recovery rate both in different aqueous conditions and recycle experiments. The adsorption experiment in the simulated wastewater solution showed that TOC-PS-HCP exhibited the greater affinity for ethylbenzene and styrene than other substrates. Furthermore, a possible mechanism for the efficient recovery of ethylbenzene and styrene was suggested on the basis of experimental and theoretical results, which may be associated with van der Waals force and π-π stacking.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS LETTERS
·
2023
·
IF 2.8
Zhang Yakun,Xu Lin,Wang Wen,Wu Qing,Zhang Yi
The efficient conversion of ethane has attracted more and more attention because of the shale gas revolution. The coupling of ethane dehydrogenation (EDH) and benzene alkylation over the 1.5Pt/HZSM-5 realize high activity close to the thermodynamic equilibrium of EDH at 500 ℃ and 0.9 bar ethane partial pressure. Meanwhile, the coupled reaction shows long-term stability during 22 h with a slightly decreased ethane conversion of 0.03% per hour and as high as 42% selectivity of ethylbenzene. Based on various characterization, including XRD, HR-TEM, NH 3 -TPD, Py-IR, TGA, it is confirmed that the coupling reaction could convert ethylene, formed by EDH over Pt sites, to ethylbenzene via benzene alkylation over Brönsted acidic sites (BAS) subsequently, and suppressing the sintering of Pt species and coke deposition induced by aromatization and deep dehydrogenation, resulting in high activity and long-time steady state. Graphical Abstract
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2023
·
IF 3.4
Shichun Weng,Wei Feng,Wenqian Wu,Zichao Guo,Liping Chen,Wanghua Chen
Nitrophenols and corresponding sodium nitrophenolates are the main side products in the production of mononitrobenzene (MNB). These side products are hazardous due to their thermal instability nature. In this article, the thermal decomposition behaviors of nitrophenols and sodium nitrophenolates were first characterized by differential scanning calorimeter and accelerating rate calorimetry techniques. Then, the influence of phenol and sodium phenolate on the thermal decomposition of MNB was studied to clarify the effect of phenolic hydroxyl groups on the thermal stability of nitrophenols. It was found that compared to nitrophenols, the exothermic peaks of sodium nitrophenolates were more intense and presented strongly autocatalytic features. Sodium phenolate could significantly decrease the decomposition temperature of MNB. Aniline was detected as the unique product in the decomposition processes of pure MNB and MNB/sodium phenolate mixtures, and the nitrosobenzene was verified as the intermediate product. It was experimentally proven that sodium phenolate could catalyze the decomposition of nitrosobenzene (the decomposition intermediate of MNB). The violent decomposition of sodium nitrophenols was caused by the intermolecular catalysis effect of phenoxy groups.
研究领域:
化学工程
·
安全科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Gang Chen,Zhichao Zhou,Xiaodan Shi,Xiaolong Zhang,Sanbao Dong,Jie Zhang
Small molecule flow improver for heavy oil recovery has attracted great attention in oilfield chemistry . In this study, 24 alkylbenzenesulfonates were synthesized and evaluated as crude oil flow improvers. The results show that all of the alkylbenzenesulfonates were effective, the chromium alkylbenzenesulfonate (CrDBS) and zinc alkylbenzenesulfonate (ZnDBS) were found to have the best performance with the viscosity reduction rate of higher than 90%. Besides, the CrDBS and ZnDBS can depress the pour point of the crude oil sample by 21.0 °C and 16.0 °C, respectively. The co-crystallization of alkylbenzenesulfonate with the saturated hydrocarbons in the crude oil could disorder the wax crystals and depress the pour point. In addition, DSC was used to reveal the mechanism of viscosity reduction and pour point depressing by alkylbenzenesulfonates. The flow improver can disturb the formation of hydrogen bonds and the π-π interaction bonds among the polycyclic aromatic hydrocarbons and the resin macromolecules . Besides, the field test using ZnDBS confirmed its good performance and promising application potential in enhancing the heavy oil recovery.
研究领域:
石油化学
·
油田开发
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）