RSC Advances
·
2017
·Vol. 7
·期 81
·51142-51150
·
IF 3.108
Ruilian Li,Jian Zhao,Fengxia Yang,Yingchao Zhang,Daniele Ramella,Yu Peng,Yi Luan
A novel magnetic Fe3O4@P4VP(poly(4-vinylpyridine))@FeCl3 core–shell structure was successfully synthesized. Its Fe3O4@P4VP core was initially prepared via polymerization of 4-vinyl pyridine on the surface of Fe3O4 microspheres. The successful introduction of the FeCl3 moiety as a catalytic active site was achieved through coordination interaction between P4VP and FeCl3. The obtained Fe3O4@P4VP@FeCl3 catalyst was applied in the selective oxidation of alcohols using molecular oxygen as the oxidant. It was shown that a variety of alcohol substrates is tolerated under optimized reaction conditions. Additionally, benzylic oxidation of hydrocarbon compounds was also evaluated using Fe3O4@P4VP@FeCl3 as the catalyst and tBuOOH as the oxidant, achieving high yields and very good selectivities. The heterogeneity of the Fe3O4@P4VP@FeCl3 core–shell catalyst was tested and the initial activity was maintained after five reuses.
研究领域:
化学
·
催化科学
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DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Xiao Zhao,Xuan Shi,Zhongshun Chen,Long Xu,Chengyi Dai,Yazhou Zhang,Xinwen Guo,Dongyuan Yang,Xiaoxun Ma
A series of ZnO-ZrO 2 solid solutions with different Zn contents were synthesized by the urea co-precipitation method, which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts. As a new benzene alkylation reagent, syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene. A suitable ratio of ZnO-ZrO 2 led to the significant improvement in the catalytic performance, and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C 9 + aromatics. The highest benzene conversion of 89.2% and toluene/xylene selectivity of 88.7% were achieved over 10% ZnO-ZrO 2 &H-ZSM-5 (Si/Al = 23) at a pressure of 3 MPa and a temperature of 450 °C. In addition, the effect of the zeolite framework structure on product distribution was examined. Similar to the molecular dynamics of aromatic hydrocarbons , H-ZSM-5 zeolites comprise 10-membered-ring pores, which are beneficial to the activation of benzene; hence, the conversion of benzene is higher. H-ZSM-35 and H-MOR zeolites exhibited small eight-membered-ring channels, which were not conducive to the passage of benzene; hence, the by-product ethylbenzene exhibits a higher selectivity. The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance, and the powder mixing method was more conducive to the conversion of syngas and benzene.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2014
·
IF 3.916
Yuxia Lv,Yaliang Chen,Ziqiang Shao,Renxu Zhang,Libin Zhao
Homogeneous tritylation of cellulose in 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid with triphenylmethy chloride as regents, pyridine or 1-butylimidazole (BIM) as base was investigated, and subsequent acetylation of the 6- O -functionalized products was further studied. The structure of products was analyzed by FTIR and 13 C NMR spectroscopy and base influences on the structure were discussed as well. The solution with pyridine as base underwent heterogeneous–homogeneous–heterogeneous process and the obtained trityl cellulose (TC) had organized structure with trityl group located completely at C-6 position of cellulose with maximum DS trityl of nearly 1. In the case of BIM as base, the solution was homogeneous for the whole reaction, but the highest DS trityl was about 0.22, with trityl group located not only at position 6 but also partially at position 2. Subsequent acetylation of the TC led to products with a preferred functionalization of the unprotected secondary OH-groups.
研究领域:
化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2023
·Vol. 29
·期 40
·e202300667
·
IF 4.3
Peng Xu,Huang Ye,Yunpeng Yao,Tingting Zhu,Junhua Luo
Graphical Multifunctional material (benzylammonium) 4 AgBiBr 8 , which has a step-like dielectric phase transition at 383 K/387 K (cooling/heating) and excellent photoelectric properties, was obtained by using rigid benzylammonium cations as templates. Layered hybrid perovskites possess exceptional semiconductor features and structural versality, making them viable candidates for developing multifunctional dielectric phase-transition materials (PTMS). However, most PTMs based on layered hybrid perovskites still suffer from Pb toxicity and low operating temperature. The recently developed hybrid double perovskites provide a new routine to designed PTMs with desired working performance and environment-friendly chemical compositions. Herein, using rigid aromatic cations as templates, we have successfully synthesized a novel double perovskite (benzylammonium) 4 AgBiBr 8 ( 1 ), which consists of corner-sharing AgBr 6 and BiBr 6 layers and benzylammonium cations. Notably, 1 exhibits a high-temperature first-order reversible solid-state phase transition at 383/387 K (cooling/heating) and switchable dielectric performance around the temperature. Compared with the soft organic chain version of the compound, the phase transition temperature of 1 shows a large enhancement of 99 K, validating the correctness of the designing strategy. In addition, 1 also exhibits semiconductor characteristics with a calculated bandgap of 2.34 eV and an optical bandgap of 2.29 eV. Remarkably, the single crystal photodetector of 1 shows a low dark current (2.12×10 −13 A), a high on/off ratio (1.77×10 3 ), and a fast response ( τ rise =125 μs and τ decay =419 μs). Such a lead-free phase transition material combined with semiconductor properties provides a new strategy to develop environmentally friendly multifunctional materials.
研究领域:
材料科学
·
物理学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2020
·
IF 4.748
Da Zou,Lijun Jin,Mei Zhong,Haoquan Hu,Fengyun Ma
A serials of modified kaolinites were prepared by calcination and further acid treatment and characterized by in-situ XRD, N 2 adsorption, NH 3 -TPD, Py-IR and 27 Al MAS-NMR. And their catalytic performance in pyrolysis of methanol/benzyl phenyl ether (MeOH-BPE), a model compound of low-rank coal, were investigated at 400 °C in a fixed-bed reactor to explore the correlation between the structure of modified samples and their catalytic performances. The results show that calcination temperature above 500 °C causes the collapse of kaolinite structure. Further acid leaching facilitates the formation of micropores and mesopores. The calcination of kaolinite leads to the transformation of six-coordinate Al atoms (Al VI ) into four and five coordinate species (Al IV and Al V ), while the subsequent acid treatment increases the contents of Al IV and Al VI and removes Al V . Total acid sites exhibit a first increase and then decrease tendency with the raising calcination temperature. In the presence of the modified kaolinites, BPE conversion significantly enhances and reaches the highest value of 91.41% over K-A-700 prepared by calcination at 700 °C of kaolinite and further acid leaching. Besides, the maximum content of phenol and toluene is also achieved due to the highest acid sites and Al IV content of K-A-700, which favors the generation of ·H, thus resulting in an obvious inhibition of bibenzyl formation but a significant increase of 2-benzylphenol. In-situ pyrolysis by time-of-flight mass spectrometry suggests that the cleavage of C al -O bond of BPE to form phenol radicals and benzyl radicals is the primary way, while insufficient ·H results in the formation of dominant product of 2-benzylphenol.
研究领域:
化学工程
·
材料科学
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DOI
高影响因子
TETRAHEDRON LETTERS
·
2020
·
IF 2.275
Haibo Zhu,Yingying Zhang,Yishuai Liu,Liu Yang,Zongbo Xie,Guofang Jiang,Zhang-Gao Le
A practical and efficient approach adopting transition-metal-free cross-coupling of sulfonyl hydrazides with benzyl ammonium salts has been developed to synthesize benzyl sulfones using Cs 2 CO 3 as base under mild conditions. The protocol employs stable and easy to handle coupling partners, and is endowed with good substrate compatibility, leading to functional benzyl sulfones in good yields.
研究领域:
有机化学
·
合成化学
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产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 55
·43972-43977
·
IF 3.84
Jun Hu,Dekui Shen,Shiliang Wu,Huiyan Zhang,Rui Xiao
The microwave-assisted cleavage of C–O linkages in benzyl phenyl ether was investigated at 200 °C in the presence of ZrP or SBA-15 doped with or without metal catalyst (Pd/C or Ru/C). The total yield of phenol and benzyl alcohol from benzyl phenyl ether depolymerization with ZrP was 26.91%, while the yield of phenol reached 26.11% for that with Pd/C. Hybrid catalysts performed effectively for promoting the formation of phenol. A conversion of 85.70% was achieved with ZrP–Pd/C catalyst, and the selectivity to phenol reached 47.32%. The highest yield of phenol was obtained at 1 h, and repolymerization was remarkable at longer reaction time. Based on the reaction using phenol and benzyl alcohol as the reactants, benzyl phenyl ether might be decomposed into phenol and benzyl alcohol following with the repolymerization producing thermally stable polymers in the presence of Pd.
研究领域:
化学工程
·
催化化学
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产品关联
DOI
高影响因子
ORGANIC & BIOMOLECULAR CHEMISTRY
·
2020
·Vol. 18
·期 6
·1073-1077
·
IF 3.412
Lingchun Zhang,Yanle Chu,Peizhi Ma,Shujuan Zhao,Qiaoyan Li,Boya Chen,Xuejiao Hong,Jun Sun
In this report, we describe a simple visible light-triggered Barbier-type reaction by employing acetenyl ketones with benzyl trifluoroborates. Through a radical–radical cross-coupling process, this photocatalytic protocol furnished a wide range of tertiary propargyl alcohols. Mechanistic investigation indicated that proton-coupled electron transfer (PCET) might be involved in the photochemical transformations.
研究领域:
有机化学
·
光化学
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DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Yong Huang,Shasha Liu,Muhammad Asif Akhtar,Bin Li,Jianbin Zhou,Shu Zhang,Hong Zhang
To understand the potential origin of char activity responsible for volatile evolution during biomass pyrolysis, the interactions between benzyl phenyl ether (BPE, a typical lignin dimer) and pinewood chars prepared under a series of thermal, acidy, and steamy conditions were investigated. The results showed the activity of low-temperature char on BPE conversion was mainly attributed to the surface O-containing functional groups. The BPE conversion decreased as the temperature for char preparation raised, resulting from the elimination of char surface functional groups to a large degree at high temperature. The low activity of high-temperature char on BPE conversion could be recovered by acid-washing to release metal-occupied carbon based active sites (e.g., small aromatic rings), and further promoted by steam activation to modify the surface property and porous structure, finally achieving a full conversion of BPE and high selectivity to the products of phenol and toluene.
研究领域:
能源科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2021
·
IF 7.514
Yi-Ping Cao,Gao-Ying Zhi,Li Han,Queting Chen,Dong-Hao Zhang
To improve the performance of lipase in biosynthesis of benzyl cinnamate, a new immobilized lipase by entrapping enzyme into nano-molecular cages was designed. Consequently, the entrapped lipase showed a robust immobilization, which diminished the leakage of lipase notably in use. Moreover, the entrapped lipase exhibited higher activity (57.1 U/mg) than free lipase (50.0 U/mg), demonstrating that the native conformation of lipase was not destroyed during immobilization. Compared with the adsorbed lipase (half-life 40.7 min) and free lipase (half-life 29.8 min), the entrapped lipase (half-life 85.3 min) increased the stability by about 2–3 times. Furthermore, the entrapped lipase was applied in biosynthesis of benzyl cinnamate, where it showed excellent activity and re-usability. After 7 cycles, the yield of benzyl cinnamate catalyzed by the entrapped lipase remained 70.2%, while the yield catalyzed by the adsorbed lipase was only about 10%. These results indicated that the nano-molecular cages could inhibit denaturation of lipase and maintain its activity well.
研究领域:
生物化学
·
酶工程
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产品关联
DOI
PubMed
高影响因子
AUSTRALIAN JOURNAL OF CHEMISTRY
·
2015
·Vol. 69
·期 1
·112-118
·
IF 1.558
Yu Yang,Yan Wu,Ruirui Li,Ying Ling,Haoyu Tang
A series of random copolypeptides, i.e. poly(γ-propyl-l-glutamate)-graft-(oligo-ethylene-glycol)-random-poly(γ-benzyl-l-glutamate)s (PPLG-g-OEG3-ran-PBLG) with similar main chain lengths and various compositions of OEG and benzyl pendants were synthesized in three steps, including ring-opening polymerization of γ-chloropropyl-l-glutamic acid-based N-carboxyanhydride (CPLG-NCA) and γ-benzyl-l-glutamic acid-based N-carboxyanhydride (BLG-NCA), nucleophilic substitution in the presence of NaN3, and copper-mediated alkyne–azide 1,3-dipolar cycloaddition. 1H NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography results confirmed the molecular structures of the resulting copolypeptides and characterized their molar masses, molar mass distributions, and the OEG/benzyl compositions. Fourier transform infrared spectroscopy and circular dichroism analysis revealed that PPLG-g-OEG3-ran-PBLG samples adopted α-helical conformations both in aqueous solution and solid state. Variable-temperature UV-visible spectroscopy revealed that PPLG-g-OEG3-ran-PBLG samples with high OEG molar content (x ≥ 0.57) possessed lower critical solution temperature-type phase transitions in water. The cloud point temperature, in the range of 22–53°C, can be readily obtained by controlling the OEG/benzyl composition.
研究领域:
高分子化学
·
材料科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES
·
2021
·
IF 3.189
Cheng Fang,Fuxiang Zhou,Xiaolong Zhu
The cyclic methacrylate monomer benzyl methacrylate (BzMA) was evaluated as an alternative to traditional methyl methacrylate (MMA) as a hard monomer in the application of an acrylate latex pressure sensitive adhesive (PSA). The influences of BzMA on the resultant latex and PSA properties were comprehensively investigated. Both FTIR and 1 H NMR analysis indicated that BzMA could be successfully introduced into the latex PSA copolymer through emulsion polymerization . TEM images illustrated that the synthesized latex particles are spherical and uniform. DSC and TGA results showed that the T g of the copolymer was elevated, while thermal stability was first increased and then decreased with the introduction of BzMA. Besides, it was also found that the water resistance of the latex PSA was improved by the presence of BzMA, which was confirmed by water contact angle measurements . Furthermore, as the BzMA content increased, the gel content slightly decreased, while sol molecular weight (M w , M n ) of the polymer increased. Finally, with respect to the adhesive properties of the PSA, it was observed that loop tack decreased, while shear strength increased with the incorporation of BzMA. 180° peel strength initially increased and then decreased with the addition of BzMA from 0 to 30 wt%, with a maximum value at 5 wt%.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
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