CATALYSIS SURVEYS FROM ASIA
·
2021
·Vol. 26
·期 1
·35-45
·
IF 3.106
Shan Shufeng,Tian Yiting,Chen Feifei,Wu Shikui,Zhou Rujin,Xie Ying,Li Ning,Zeng Xingye,Lin Cunhui,Yu Wei
NiMoS supported on ZSM-5 with different Si/Al ratio, crystallite size and pore structure was prepared by incipient impregnation method and applied in 1, 3, 5-trimethylbenzene (1, 3, 5-TMB) hydrodealkylation (HDAK). The physicochemical properties of samples were characterized by XRD, FTIR, SEM, N 2 adsorption–desorption, NH 3 -TPD, Py-FTIR, H 2 -TPR, HRTEM and TGA. It is demonstrated that for microporous NiMoS/ZSM-5, acid amount and crystallite size of HZSM-5 are key factors affecting HDAK performance. The larger acid amount and smaller crystallite size can promote the conversion of 1, 3, 5-TMB, especially the dealkylation reaction, resulting in higher BTX yield. Compared to NiMoZ-3, mesopores in micro-mesoporous NiMoAKZ-3 are beneficial to accessibility of 1, 3, 5-TMB to NiMoS and acid sites in close proximity, and the diffusion of reactant and product molecules inside pores, thus resulting in superior HDAK performance of NiMoAKZ-3. Moreover, the reaction network of 1, 3, 5-TMB HDAK was revealed according to product distribution. Graphic Abstract NiMoS supported on ZSM-5 was developed for heavy aromatic hydrodealkylation (HDAK). Acid amount and crystallite size of microporous ZSM-5 are key factors affecting 1,3,5-trimethylbenzene (1,3,5-TMB) HDAK. Mesopores inside ZSM-5 facilitate accessibility of 1,3,5-TMB to NiMoS and acid sites in close proximity and improve HDAK performance.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
TETRAHEDRON
·
2018
·
IF 2.377
Lingxian Liu,Zengguang Li,Changjun Chen,Huanrong Li,Lijin Xu,Zhiyong Yu
An efficient protocol for dealkylation of aryl alkyl ethers under the catalysis of inexpensive and easily reusable Cu 2 O has been described. The phenol products were obtained in high yields, and a range of functional groups were well tolerated. The choice of solvent is critical to the catalysis, and CH 3 OH proved to be the optimal choice. Mechanistic investigations showed that this reaction possibly proceeds via a single-electron transfer (SET) process.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 21
·9847-9859
·
IF 4.197
Jisheng Zhang,Yujuan Wang,Nengchao Luo,Zhuqi Chen,Kangbing Wu,Guochuan Yin
Utilization of dioxygen as the terminal oxidant at ambient temperature is always a challenge in redox chemistry, because it is hard to oxidize a stable redox metal ion like iron(III) to its high oxidation state to initialize the catalytic cycle. Inspired by the dioxygenation and co-oxidase activity of lipoxygenases, herein, we introduce an alternative protocol to activate the sluggish iron(III) species with non-redox metal ions, which can promote its oxidizing power to facilitate substrate oxidation with dioxygen, thus initializing the catalytic cycle. In oxidations of N,N-dimethylaniline and its analogues, adding Zn(OTf)2 to the [Fe(TPA)Cl2]Cl catalyst can trigger the amine oxidation with dioxygen, whereas [Fe(TPA)Cl2]Cl alone is very sluggish. In stoichiometric oxidations, it has also been confirmed that the presence of Zn(OTf)2 can apparently improve the electron transfer capability of the [Fe(TPA)Cl2]Cl complex. Experiments using different types of substrates as trapping reagents disclosed that the iron(IV) species does not occur in the catalytic cycle, suggesting that oxidation of amines is initialized by electron transfer rather than hydrogen abstraction. Combined experiments from UV-Vis, high resolution mass spectrometry, electrochemistry, EPR and oxidation kinetics support that the improved electron transfer ability of iron(III) species originates from its interaction with added Lewis acids like Zn2+ through a plausible chloride or OTf− bridge, which has promoted the redox potential of iron(III) species. The amine oxidation mechanism was also discussed based on the available data, which resembles the co-oxidase activity of lipoxygenases in oxidative dealkylation of xenobiotic metabolisms where an external electron donor is not essential for dioxygen activation.
研究领域:
化学
·
生物学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2024
·
IF 6.7
Qiuxiang Yao,Lei He,Duo Ma,Yong Zhang,Dan Zhang,Ming Sun
The naphthalene derivatives in coal tar naphthalene and anthracene oil fractions mostly contain short-chain alkyl groups. The enrichment of PAHs (polycyclic aromatic hydrocarbons, mainly including naphthalene, anthracene, and pyrene) by the dealkylation of PAHs-rich fraction in coal tar was assumed to obtain high-purity PAHs by distillation. Based on this strategy, using 2-methylnaphthalene as the model compound, and the influences of catalysts with different supports (SiO 2 , Al 2 O 3 , ZSM-5, Beta, and HY) and different active metal components (Ni, Co, Mo, and W) prepared by the equivalent-volume impregnation method on the hydro-dealkylation performance of 2-methylnaphthalene under different technological conditions (temperature, H 2 initial pressure and reaction time) were systematically investigated in a pressurized batch reactor. The experimental results show that the conversion rate of 2-methylnaphthalene is 81.23 % and the selectivity of naphthalene is 64.22 % under conditions of 480 °C, 2 MPa, 4 h, and 6 W-HY. Loading 0.8 wt% La on the 6 W-HY catalyst can improve the dispersion of active metal component W on the support, but it does not change the skeleton structure of the support. In addition, one-dimensional diffusion is the most probable reaction mechanism for 2-methylnaphthalene, and the evolution profiles of naphthalene can be reflected by the reaction mechanism with a reaction order of n = 4 using the model fitting method.
研究领域:
化学工程
·
催化
·
石油化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Bei Ye,Ziye Liu,Xiaoqin Zhu,Hanjing Wu,Zifan Liang,Wenlong Wang,Qianyuan Wu,Hongying Hu,Xinhao Zhang
Chlorination is widely used for disinfection of water and wastewater. Ammonia/chlorine co-exposure can be easily achieved when ammonia is present in water. In this study, ammonia and chlorine showed synergistic effect on atrazine (ATZ) degradation. A degradation efficiency of 50.2% was obtained in 10 min with a Cl/N molar ratio of 1.6. By contrast, free chlorine and chloramines barely degraded ATZ. The synergistic effect involved formation of hydroxyl radicals ( OH) and reactive chlorine species. The radical concentrations followed the order of ClO (4.8 × 10 −13 M) > OH (4.1 × 10 −13 M) > Cl (3.0 × 10 −15 M). The dominant radical was OH (>80% contribution), followed by ClO (less than18% contribution), which had relatively lower reactivity with ATZ. The synergism was pH dependent, with OH largely suppressed by 98% when the pH was acidic or basic rather than neutral, resulting in a decrease in ATZ degradation. The transformation products detected indicated that ATZ degradation involved dealkylation and dechlorination–hydroxylation, and lower yields of oxidation byproducts were obtained by ammonia/chlorine synergistic oxidation process compared to direct chlorination.
研究领域:
环境科学
·
水处理
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMBIOCHEM
·
2014
·Vol. 15
·期 16
·2443-2449
·
IF 3.06
Yue-Cai Yin,Hui-Lei Yu,Zheng-Jiao Luan,Ren-Jie Li,Peng-Fei Ouyang,Jing Liu,Jian-He Xu
Graphical Catalytic versatility of P450 La MO : A new redox-self-sufficient P450 of the CYP116B subfamily was discovered by data mining. A substrate spectrum study showed that it was a catalytic versatile monooxygenase, mediating oxidation reactions as diverse as hydroxylation, alkene epoxidation, O -dealkyl- ation, sulfoxidation, and even hydration. A new member of the CYP116B subfamily—P450 La MO —was discovered in Labrenzia aggregata by genomic data mining. It was successfully overexpressed in Escherichia coli , purified, and subsequently characterized spectroscopically, and its catalytic properties were assessed. Substrate profiling of the P450 La MO revealed that it was a versatile catalyst, exhibiting hydroxylation and epoxidation activities as well as O -dealkylation and asymmetric sulfoxidation activities. Diverse compounds, including alkylbenzenes, aromatic bicyclic molecules, and terpenoids, were shown to be hydroxylated by P450 La MO . Such diverse catalytic activities are uncommon for the bacterial P450s, and the P450 La MO -mediated stereoselective hydroxylation of inactivated C H bonds—ubiquitous and relatively unreactive in organic molecules—is particularly unusual. The self-sufficient nature of P450 La MO , coupled with its broad substrate range, highlights it as an ideal template for directed evolution towards various applications.
研究领域:
生物化学
·
酶学
·
微生物学
·
分子生物学
✓ 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）