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Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1267-1279 doi: 10.1007/s11705-022-2291-7

摘要: The emergence of vitrimer, a new class of polymer materials can address the problem of recyclability, reprocess ability and recyclability of thermosetting plastics. Rosin, a natural product, is an ideal raw material for the preparation of polymers in a more sustainable way. Nevertheless, due to the huge steric hindrance caused by the hydrogenated phenanthrene ring structure, the cross-link density of materials is frequently lowered. In this study, hydrogenated rosin was adopted for preparing hydrogenated rosin side-chain type diacids, which were reacted with mixed epoxy to obtain rosin side-chain type vitrimers. It was completely characterized by differential scanning calorimetry test, thermogravimetric analysis, shape memory test and self-healing test. The prepared vitrimers exhibited good self-healing properties, excellent heat resistance (Td = 352 °C) as well as high mechanical properties (tensile strength of 46.75 MPa). The tricyclic diterpene structure of rosin was introduced into the side chain in order to avoid the reduction of cross-link density resulting from the huge steric hindrance of the rigid tricyclic hydrophenylene skeleton. Vitrimers can undergo dynamic transesterification reaction without external catalysts due to the autocatalytic effect of tertiary amines from epoxy. Moreover, our work expanded the application field of rosin, increased the added value of rosin, and provided a novel method for preparing rosin-based vitrimers with ideal properties.

关键词: vitrimers     rosin     catalyst-free     high mechanical properties     dynamic transesterification reaction    

Microwave-assisted catalyst-free hydrolysis of fibrous cellulose for deriving sugars and biochemicals

Songshan Jiang, Helen Daly, Huan Xiang, Ying Yan, Huiping Zhang, Christopher Hardacre, Xiaolei Fan

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 718-726 doi: 10.1007/s11705-019-1804-5

摘要: Microwave (MW) assisted catalyst-free hydrolysis of fibrous cellulose (FC, cellulolysis) at 200°C promoted a cellulose conversion of ca 37.2% and quantitative production of valuable C5/C6 sugars (e.g , glucose) and the according platform biochemicals (e.g , 5-hydroxymethylfurfural), corresponding to an overall selectivity of 96.5%. Conversely, conventional hydrothermal cellulolysis under similar conditions was not effective, even after 24 h, carbonising the FC. Based on the systematic study of MW-assisted cellulolysis, the specific interaction between water molecules and macroscopic FC under the MW irradiation was proposed, accounting for the interpretation of the experimental observation. The kinetic energy of water molecules under the MW irradiation facilitated the C C (in the non-hindered surface CH OH groups) and C O C bond breaking (inside the cellulose cavities) in FC, producing primary cellulolysis products of xylose, glucose and cellobiose.

关键词: microwave     fibrous cellulose     hydrolysis     sugars     mechanism    

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

《能源前沿(英文)》 2018年 第12卷 第2期   页码 233-238 doi: 10.1007/s11708-018-0529-3

摘要: Heteroatom-doping of pristine graphene is an effective route for tailoring new characteristics in terms of catalytic performance which opens up potentials for new applications in energy conversion and storage devices. Nitrogen-doped graphene (N-graphene), for instance, has shown excellent performance in many electrochemical systems involving oxygen reduction reaction (ORR), and more recently glucose oxidation. Owing to the excellent sensitivity of N-graphene, the development of highly sensitive and fast-response enzymatic biosensors is made possible. However, a question that needs to be addressed is whether or not improving the anodic response to glucose detection leads to a higher overall performance of enzymatic biofuel cell (eBFC). Thus, here we first synthesized N-graphene via a catalyst-free single-step thermal process, and made use of it as the biocatalyst support in a membraneless eBFC to identify its role in altering the performance characteristics. Our findings demonstrate that the electron accepting nitrogen sites in the graphene structure enhances the electron transfer efficiency between the mediator (redox polymer), redox active site of the enzymes, and electrode surface. Moreover, the best performance in terms of power output and current density of eBFCs was observed when the bioanode was modified with highly doped N-graphene.

关键词: enzymatic fuel cell     nitrogen-doped graphene     reduced graphene oxide     catalyst-free synthesis    

Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substitutedperovskite carrier on the catalyst activities

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 59-64 doi: 10.1007/s11705-007-0012-x

摘要: The perovskite-type compound LaMnO was substituted for the part of La in position A and for the part of Mn in position B by citrate method. The phases were detected by X-ray diffraction. Powder morphologies were scanned by scanning electron microscopy. The valence of atoms was determined by X-ray photoelectron spectroscopy. It was found that the perovskite can form crystal defect and increase the proportion of high valence B element by doping. Active component Pd was loaded on various perovskite supports for synthesis of diphenyl carbonate. The results showed that the activities of catalysts in which supports have crystal defect by substitution were higher. It can be concluded that perovskite with defect structure by doping could lead to the formation of oxygen vacancy where the lattice oxygen became exchangeable with the oxygen gas. Also, this improved the redox process of the carrier by transferring electrons and activities of catalysts.

关键词: photoelectron spectroscopy     diphenyl carbonate     proportion     diffraction     perovskite    

Fischer-Tropsch synthesis by reduced graphene oxide nanosheets supported cobalt catalysts: Role of supportand metal nanoparticle size on catalyst activity and products selectivity

Hasan Oliaei Torshizi, Ali Nakhaei Pour, Ali Mohammadi, Yahya Zamani, Seyed Mehdi Kamali Shahri

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 299-309 doi: 10.1007/s11705-020-1925-x

摘要: In this paper, a series of cobalt catalysts supported on reduced graphene oxide (rGO) nanosheets with the loading of 5, 15 and 30 wt-% were provided by the impregnation method. The activity of the prepared catalysts is evaluated in the Fischer-Tropsch synthesis (FTS). The prepared catalysts were carefully characterized by nitrogen adsorption-desorption, hydrogen chemisorption, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, temperature programmed reduction, transmission electron microscopy, and field emission scanning electron microscopy techniques to confirm that cobalt particles were greatly dispersed on the rGO nanosheets. The results showed that with increasing the cobalt loading on the rGO support, the carbon defects are increased and as a consequence, the reduction of cobalt is decreased. The FTS activity results showed that the cobalt-time yield and turnover frequency passed from a maximum for catalyst with the Co average particle size of 15 nm due to the synergetic effect of cobalt reducibility and particle size. The products selectivity results indicated that the methane selectivity decreases, whereas the C selectivity raises with the increasing of the cobalt particle size, which can be explained by chain propagation in the primary chain growth reactions.

关键词: cobalt catalyst     cobalt particle size     Fischer-Tropsch synthesis     reduced graphene oxide     supported catalyst    

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

《化学科学与工程前沿(英文)》 2023年 第17卷 第6期   页码 772-783 doi: 10.1007/s11705-022-2280-x

摘要: Development of a titanium silicalite-1 (TS-1) catalyst with good crystallinity and a four-coordinate Ti framework is critical for efficient catalytic oxidation reaction under mild conditions. Herein, a size-controlled TS-1 zeolite (TS-1#0.1ACh (acetylcholine)) was synthesized via steam-assisted crystallization by introducing acetylcholine as a crystal growth modifier in the preparation process, and TS-1#0.1ACh was also employed in epoxidations of different substrates containing C=C double bonds. The crystalline sizes of the as-synthesized TS-1#0.1ACh catalysts were controlled with the acetylcholine content, and characterization results showed that the particle sizes of highly crystalline TS-1#0.1ACh zeolite reached 3.0 μm with a good Ti framework. Throughout the synthetic process, the growth rate of the crystals was accelerated by electrostatic interactions between the connected hydroxyl groups of the acetylcholine modifier and the negatively charged skeleton of the pre-zeolites. Furthermore, the TS-1#0.1ACh catalyst demonstrated maximum catalytic activity, good selectivity and high stability during epoxidation of allyl chloride. Importantly, the TS-1#0.1ACh catalyst was also highly versatile and effective with different unsaturated substrates. These findings may provide novel, easily separable and large TS-1 catalysts for efficient and clean industrial epoxidations of C=C double bonds.

关键词: size-controlled TS-1     crystal modifier     steam-assisted crystallization     epoxidation    

Polyethylene glycol-supported ionic liquid as a highly efficient catalyst for the synthesis of propylene

Rui YAO, Hua WANG, Jinyu HAN

《化学科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 239-245 doi: 10.1007/s11705-012-1297-y

摘要: The coupling reaction of propylene and CO to form propylene carbonate (PC) was promoted by an ionic liquid (IL) covalently bound to polyethylene glycol (PEG). The supported ionic liquid, which has both acidic and basic components, proved to be an active catalyst for PC synthesis under mild conditions. The effects of different cations and anions, reaction temperature, CO pressure, and reaction time were investigated. It was demonstrated that the acid group in the catalyst plays an important role in the reaction. With this system, a high PC yield (95%) was achieved under mild conditions (3.0 MPa, 120°C and 4 h) without a co-solvent. In addition, the catalyst was readily recovered and reused. Based on the experimental results, a plausible mechanism for the catalyst was proposed.

关键词: ionic liquid     PEG-supported ionic liquid     carbon dioxide     propylene carbonate    

Synthesis of methanol and ethanol over CuZnAl slurry catalyst prepared by complete liquid-phase technology

Wei HUANG, Linmei YU, Wenhui LI, Zhili MA

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 472-475 doi: 10.1007/s11705-010-0525-6

摘要: A new method, named the complete liquid-phase technology, has been applied to prepare catalysts for methanol synthesis. Its main innovative thought lies in preparing slurry catalysts directly from raw solution. Activity tests indicate that the CuZnAl slurry catalyst prepared by the new method can efficiently catalyze conversion of syngas to ethanol in a slurry reactor, while CO conversion reaches 35.9% and ethanol selectivity is more than 20%, with a total alcohol selectivity of more than 87%. No deactivation was found during the 192 h reaction .

关键词: methanol     slurry     ethanol     complete liquid-phase technology     CuZnAl catalyst    

洞察无有机模板合成沸石分子筛催化材料

王叶青,吴勤明,孟祥举,肖丰收

《工程(英文)》 2017年 第3卷 第4期   页码 567-574 doi: 10.1016/J.ENG.2017.03.029

摘要:

作为当前最重要的工业催化材料之一,沸石分子筛的合成一般是在有机模板存在的条件下水热合成的,但是该合成过程会产生大量的有害气体和废水,不仅污染环境,还增加了生产成本。本文旨在概述有机模板在沸石分子筛合成过程中的角色,并据此分别设计沸石晶种和导向剂溶液导向的无有机模板条件下合成沸石分子筛的路线。在此基础上,总结并揭示了在无有机模板的Na+ 体系中合成的沸石分子筛的微孔体积与Si/Al 比值的关系,即微孔体积越大,Si/Al 比值越小,这对于无有机模板条件下合成Si/Al 比值可调控的沸石分子筛和设计它们的合成路线具有重要意义。

关键词: 无有机模板合成     沸石分子筛     沸石晶种     沸石导向剂溶液     Si/Al 比值    

Light olefins synthesis from С

Anton SHALYGIN, Evgenii PAUKSHTIS, Evgenii KOVALYOV, Bair BAL’ZHINIMAEV

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 279-288 doi: 10.1007/s11705-013-1338-1

摘要: A two-step process was employed to convert methane or ethane to light olefins via the formation of an intermediate monoalkyl halide. A novel K RuOCl /TiO catalyst was tested for the oxidative chlorination of methane and ethane. The catalyst had high selectivity for methyl and ethyl chlorides, 80% and 90%, respectively. During the oxychlorination of ethane at ≥250°C, the formation of ethylene as a reaction product along with ethyl chloride was observed. In situ Fourier transform infrared studies showed that the key intermediate for monoalkyl chloride and ethylene formation is the alkoxy group. The reaction mechanism for the oxidative chlorination of methane and ethane over the Ru-oxychloride catalyst was proposed. The novel fiber glass catalyst was also tested for the dehydrochlorination of alkyl chlorides to ethylene and propylene. Very high selectivities (up to 94%–98%) for ethylene and propylene formation as well as high stability were demonstrated.

关键词: oxychlorination     methane     ethane     light olefins     ruthenium catalyst    

Recent advances on metal-free graphene-based catalysts for the production of industrial chemicals

Zhiyong Wang, Yuan Pu, Dan Wang, Jie-Xin Wang, Jian-Feng Chen

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 855-866 doi: 10.1007/s11705-018-1722-y

摘要: With the development of carbon catalysts, graphene-based metal-free catalysts have drawn increasing attention in both scientific research and in industrial chemical production processes. In recent years, the catalytic activities of metal-free catalysts have significantly improved and they have become promising alternatives to traditional metal-based catalysts. The use of metal-free catalysts greatly improves the sustainability of chemical processes. In view of this, the recent progress in the preparation of graphene-based metal-free catalysts along with their applications in catalytic oxidation, reduction and coupling reactions are summarized in this review. The future trends and challenges for the design of graphene-based materials for industrial organic catalytic reactions with good stabilities and high catalytic performance are also discussed.

关键词: graphene-based materials     metal-free catalyst     industrial chemical productions     catalytic reaction    

A facile synthesis of high activity cube-like Pt/carbon composites for fuel cell application

Reza B. MOGHADDAM, Samaneh SHAHGALDI, Xianguo LI

《能源前沿(英文)》 2017年 第11卷 第3期   页码 245-253 doi: 10.1007/s11708-017-0492-4

摘要: High activity catalyst with simple low-cost synthesis is essential for fuel cell commercialization. In this study, a facile procedure for the synthesis of cube-like Pt nanoparticle (Pt ) composites with high surface area carbon supports is developed by mixing precursor of Pt with carbon supports in organic batches, hence, one pot synthesis. The Pt grow with Vulcan XC-72 or Ketjen black, respectively, and then treated for 5.5 h at 185ºC (i.e., Pt /V and Pt /K). The resulting particle sizes and shapes are similar; however, Pt /K has a larger electrochemical active surface area (EASA) and a remarkably better formic acid (FA) oxidation performance. Optimization of the Pt /K composites leads to Pt /K that has been treated for 10 h at 185ºC. With a larger EASA, Pt /K is also more active in FA oxidation than the other Pt /K composites. Impedance spectroscopy analysis of the temperature treated and as-prepared (i.e., untreated) Pt /K composites indicates that Pt /K is less resistive, and has the highest limiting capacitance among the Pt /K electrodes. Consistently, the voltammetric EASA is the largest for Pt /K. Furthermore, Pt /K is compared with two commercial Pt/C catalysts, Tanaka Kikinzoku Kogyo (TKK), and Johnson Matthey (JM)Pt/C catalysts. The TKK Pt/C has a higher EASA than Pt /K, as expected from their relative particles sizes (3–4 nm vs. 6–7 nm for Pt /K), however, Pt /K has a significantly better FA oxidation activity.

关键词: synthesis     cube-like Pt     Pt/C composite     catalyst     impedance    

A new method for the synthesis of molybdovanadophosphoric heteropoly acids and their catalytic activities

ZHANG Fumin, GUO Maiping, GE Hanqing, WANG Jun

《化学科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 296-299 doi: 10.1007/s11705-007-0054-0

摘要: An environmentally benign method for the synthesis of heteropoly acids HPMoVO·HO (PMoV, = 1−3) was developed by the reaction of an aqueous slurry which contained stoichiometric amounts of MoO, VO and HPO. Characterization of the as-synthesized catalysts with inductively coupled plasma (ICP) elemental analysis, thermogravimetry (TG), X-ray diffraction (XRD) and infrared (IR) spectroscopy indicated that V ions substituted for Mo ions in Keggin-type phosphomolybdic acid. The as-synthesized samples were found to be an efficient catalyst for the hydroxylation of benzene which was carried out in a mixed solvent of acetonitrile and acetic acid with aqueous hydrogen peroxide as oxidant. PMoV exhibi ted the highest benzene conversion of 34.5% with phenol selectivity of 100%.

关键词: conversion     heteropoly     Characterization     efficient catalyst     Keggin-type phosphomolybdic    

Review of SO42-/MxOy solid superacid catalysts

Yanni WU, Shijun LIAO

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 330-343 doi: 10.1007/s11705-009-0208-3

摘要: Some metal oxides modified with sulfate ions form highly acidic or superacidic catalysts. solid superacid catalysts, play a vital role in more and more fields such as organic synthesis, fine chemicals, pharmaceuticals, and means for strengthening environmental safeguards. This review highlights the recent development of solid superacid catalysts based on , including synthesis method, characterization of acid sites and acid strength, and applications.

关键词: solid superacid catalyst     synthesis method     characterization     applications    

Template-free synthesis of hierarchically macro-mesoporous Mn-TiO

Zhao Peng, Li-Hua Chen, Ming-Hui Sun, Pan Wu, Chang Cai, Zhao Deng, Yu Li, Wei-Hong Zheng, Bao-Lian Su

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 43-49 doi: 10.1007/s11705-017-1679-2

摘要: This study described a template-free method for the synthesis of hierarchically macro-mesoporous Mn-TiO catalysts. The promoting effect of Mn doping and the hierarchically macro-mesoporous architecture on TiO based catalysts was also investigated for the selective reduction of NO with NH . The results show that the catalytic performance of TiO based catalysts was improved greatly after Mn doping. Meanwhile, the Mn-TiO catalyst with the hierarchically macro-mesoporous architecture has a better catalytic activity than that without such an architecture.

关键词: titania     hierarchically macro-mesoporous structure     Mn-doping     selective catalytic reduction    

标题 作者 时间 类型 操作

Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and

期刊论文

Microwave-assisted catalyst-free hydrolysis of fibrous cellulose for deriving sugars and biochemicals

Songshan Jiang, Helen Daly, Huan Xiang, Ying Yan, Huiping Zhang, Christopher Hardacre, Xiaolei Fan

期刊论文

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

期刊论文

Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substitutedperovskite carrier on the catalyst activities

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

期刊论文

Fischer-Tropsch synthesis by reduced graphene oxide nanosheets supported cobalt catalysts: Role of supportand metal nanoparticle size on catalyst activity and products selectivity

Hasan Oliaei Torshizi, Ali Nakhaei Pour, Ali Mohammadi, Yahya Zamani, Seyed Mehdi Kamali Shahri

期刊论文

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

期刊论文

Polyethylene glycol-supported ionic liquid as a highly efficient catalyst for the synthesis of propylene

Rui YAO, Hua WANG, Jinyu HAN

期刊论文

Synthesis of methanol and ethanol over CuZnAl slurry catalyst prepared by complete liquid-phase technology

Wei HUANG, Linmei YU, Wenhui LI, Zhili MA

期刊论文

洞察无有机模板合成沸石分子筛催化材料

王叶青,吴勤明,孟祥举,肖丰收

期刊论文

Light olefins synthesis from С

Anton SHALYGIN, Evgenii PAUKSHTIS, Evgenii KOVALYOV, Bair BAL’ZHINIMAEV

期刊论文

Recent advances on metal-free graphene-based catalysts for the production of industrial chemicals

Zhiyong Wang, Yuan Pu, Dan Wang, Jie-Xin Wang, Jian-Feng Chen

期刊论文

A facile synthesis of high activity cube-like Pt/carbon composites for fuel cell application

Reza B. MOGHADDAM, Samaneh SHAHGALDI, Xianguo LI

期刊论文

A new method for the synthesis of molybdovanadophosphoric heteropoly acids and their catalytic activities

ZHANG Fumin, GUO Maiping, GE Hanqing, WANG Jun

期刊论文

Review of SO42-/MxOy solid superacid catalysts

Yanni WU, Shijun LIAO

期刊论文

Template-free synthesis of hierarchically macro-mesoporous Mn-TiO

Zhao Peng, Li-Hua Chen, Ming-Hui Sun, Pan Wu, Chang Cai, Zhao Deng, Yu Li, Wei-Hong Zheng, Bao-Lian Su

期刊论文