检索结果-南通市图书馆

Redox-neutral ipso/ortho alkenylcyanation of(hetero)arylboronic acid enabled by 1,4-rhodium migration and fragmentation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2023年第8期66卷 2283-2291页

作者： Chenxia Guo Donghui Xing Huanfeng Jiang Liangbin Huang The state key laboratory of pulp and paper engineering School of Chemistry and Chemical EngineeringKey Laboratory of Functional Molecular Engineering of Guangdong ProvinceSouth China University of TechnologyGuangzhou510640China

A mild,chemoselective,redox-neutral ipso/ortho alkenylcyanation of arylboronic acids with homopropargylic malononitriles via 1,4-rhodium migration and fragmentation is reported.A variety of 2-vinyl arylnitriles are obtained in good yields(51examples,ava.69%yields)through this strategy,which is characterized by its broad substrate scope,great functional group tolerance,and mild conditions.Mechanism studies indicate that the fragmentation is temperature dependent.The primary asymmetric exploration for the non-fragmentation product already shows promising results.The separation of the two cyano groups of homopropargylic malononitriles results in the formation of aromatic nitrile and aliphatic nitrile in one molecule,which enables the further transformations of the products.

关键词： 1,4-rhodium migration alkenylcyanation cyano transfer malononitriles

Palladium-Catalyzed anti-Markovnikov Halosulfonamidation of Unactivated Alkene

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第5期42卷 464-470页

作者： Bowen Wang Jianxiao Li Wanqing Wu Huanfeng Jiang state key laboratory of pulp and paper engineering Key Laboratory of Functional Molecular Engineering of Guangdong ProvinceSchool of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhouGuangdong510641 China

Palladium-catalyzed regioselective amination of unactivated alkene remains a challenge and is of great interest.Herein,a three-component coupling of unactivated alkene,sulfonamide,and N-halo compounds accessing vicinal haloamine has been conceived.This aminohalogenation represents a modular and regioselective strategy.The electrophilic halogenating agent enables regioselective anti-Markovnikov aminopalladation and facilitates subsequent halogenation events.And this protocol is characterized by gram-scale syntheses and late-stage functionalizations.Of note,the recovered byproduct phthalimide allows for reusing by conversion to the starting material.

关键词： Unactivated alkene anti-Markovnikov aminopalladation Vicinal haloamine Palladium catalysis Halosulfonamidation Selectivity N-Halo compounds

Radical and(photo)electron transfer induced mechanisms for lignin photo-and electro-catalytic depolymerization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2023年第2期8卷 383-405页

作者： Kejia Wu Minglong Cao Qiang Zeng Xuehui Li School of Chemistry and Chemical engineering State Key Laboratory of Pulp&Paper EngineeringSouth China University of TechnologyGuangzhou510640China

As one of the three major components of woody biomass,lignin is a kind of natural organic polymer and the only abundant natural renewable resource with aromatic nucleus.Chemical catalysis induced depolymerization is an important and effective approach for lignin utilization.In particular,photocatalysis and electrocatalysis show great potential in accurately activating C-O/C-C bonds,which is a critical point of selective cleavage of lignin.In this contribution,we focus on radical and(photo)electron transfer induced reaction mechanisms of the photo(electro)catalytic depolymerization of lignin.Primarily,the general situation of Carbon-centered radicals and active oxygen species mediated lignin conversion has been discussed.Then the mechanisms for(photo)electron transfer mediated lignin depolymerization have been summarized.At the end of this review,the challenges and opportunities of photo(electro)catalysis in the applications of lignin valorization have been forecasted.

关键词： Lignin Photocatalysis Electrocatalysis Depolymerization Reaction mechanism

Quantitative Extraction of p-Coumaric Acid and Ferulic Acid in Different Gramineous Materials and Structural Changes of Residual Alkali Lignin

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2023年第2期11卷 555-566页

作者： Tanhao Zhang Shuo Zhang Wu Lan Fengxia Yue state key laboratory of pulp and paper engineering School of Light Industry and EngineeringSouth China University of TechnologyGuangzhou510640China

Ferulic acid(FA)and p-coumaric acid(pCA)in bagasse,wheat straw,corn straw,and corncob were extracted by alkaline hydrolysis and characterized by gas chromatography(GC)and gas chromatography-mass spectrometry(GC-MS).It was found that the FA and most of the pCA in gramineous biomass could be dissociated and released after being treated with 1 M NaOH at 100℃for 4 h.The yields of pCA/FA in bagasse,wheat straw,corn straw,and corncob determined by GC-FID are 39.8/11.5,13.7/11.0,28.0/11.0,and 35.1/14.5 mg/g,respectively.The raw materials and the treated solid residues were characterized by gel-state 2D Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance(2D HSQC NMR).It was found that only a small amount of lignin was detected in the residue after alkali treatment,indicating that the alkali treatment conditions can effectively cleave the FA and pCA.Additionally,the lignin in the alkali solution was recovered and characterized by 2D HSQC NMR.The FA was not able to be detected by NMR,whereas a small amount of pCA remained in the alkali lignin.This study reveals the structural change of residual lignins during the quantitative isolation of FA and pCA,which is essential for the selective isolation of pCA/FA and valorization of residual alkali lignin.

关键词： Gramineae ferulic acid p-coumaric acid alkali lignin alkaline pretreatment

Flame Retardant Material Based on Cellulose Scaffold Mineralized by Calcium Carbonate

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2024年第1期12卷 89-102页

作者： Jinshuo Wang Lida Xing Fulong Zhang Chuanfu Liu state key laboratory of pulp and paper engineering School of Light Industry and EngineeringSouth China University of TechnologyGuangzhou510640China

Wood-based functional materials have developed rapidly.But the flammability significantly limits its further application.To improve the flame retardancy,the balsa wood was delignified by NaClO2 solution to create a cellulose scaffold,and then alternately immersed in CaCl2 ethanol solution and NaHCO3 aqueous solution under vacuum.The high porosity and wettability resulting from delignification benefited the following mineralization process,changing the thermal properties of balsa wood significantly.The organic-inorganic wood composite showed abundant CaCO3 spherical particles under scanning electron microscopy.The peak of the heat release rate of delignified balsa-CaCO3 was reduced by 33%compared to the native balsa,according to the cone calorimetric characterization.The flame test demonstrated that the mineralized wood was flame retardant and selfextinguish.Additionally,the mineralized wood also displayed lower thermal conductivity.This study developed a feasible way to fabricate a lightweight,fire-retardant,self-extinguishing,and heat-insulating wood composite,providing a promising route for the valuable application of cellulosic biomass.

关键词： Cellulose scaffold delignification CaCO3 mineralization fire retardancy

结构诱导富集氧空位的空心Co3O4催化CO高效氧化（英文）

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2020年第2期63卷 267-275页

作者：陈芝杰王亚晶梁倩楠陈立宇詹伟腾李映伟 state key laboratory of pulp and paper engineering School of Chemistry and Chemical Engineering South China University of Technology

四氧化三钴(Co3O4)被认为是一种具有应用前景的CO氧化催化剂.根据Mars-van Krevelen机理, Co3O4的氧空位对提高催化活性起到非常重要的作用.本文提出一种新颖的结构诱导策略以制备具有丰富氧空位的空心Co3O4,实现高效CO氧化.通过还原-... 详细信息

四氧化三钴(Co3O4)被认为是一种具有应用前景的CO氧化催化剂.根据Mars-van Krevelen机理, Co3O4的氧空位对提高催化活性起到非常重要的作用.本文提出一种新颖的结构诱导策略以制备具有丰富氧空位的空心Co3O4,实现高效CO氧化.通过还原-氧化热解过程,金属有机骨架前驱体(如ZIF-67)被转化成镶嵌有空心Co3O4颗粒的空心碳壳材料.空心Co3O4颗粒具有丰富的氧空位,在130°C时能催化CO完全氧化转化,远低于实心Co3O4材料的完全转化温度(220°C).此外,空心碳壳结构可以降低氧化过程中的分子扩散阻力.得益于其独特的中空结构, H-Co3O4@H-C在高达240,000 m L h^–1gcat.^–1的空速下显示出与贵金属催化剂相媲美的活性.此外, H-Co3O4@H-C催化剂也显示出良好的稳定性,反应24 h后活性才略微下降.

关键词： Co3O4 金属有机骨架贵金属催化剂氧空位四氧化三钴转化温度扩散阻力中空结构

Synergistic effects and kinetics analysis for co-pyrolysis of vacuum residue and plastics

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and engineering 2024年第5期18卷 71-81页

作者： Chao Wang Xiaogang Shi Aijun Duan Xingying Lan Jinsen Gao Qingang Xiong state key laboratory of Heavy Oil Processing China University of Petroleum-BeijingBeijing 102249China state key laboratory of pulp and paper engineering South China University of TechnologyGuangzhou 510640China

This study utilizedathermogravimetric analyzer to assess the thermal decomposition behaviors and kinetics properties of vacuum residue(VR)and low-density polyethylene(LDPE)polymers.The kinetic parameters were calculated using the Friedman technique.To demonstrate the interactive effects between LDPE and VR during the co-pyrolysis process,the disparity in mass loss and mass loss rate between the experimental and calculated values was computed.The co-pyrolysis curves obtained through estimation and experimentation exhibited significantdeviations,whichwerei influencedby temperature and mixing ratio.A negative synergistic interaction was observed between LDPE and VR,although this inhibitory effect could be mitigated or eliminated by reducing the LDPE ratio in the mixture and increasing the co-pyrolysistemperature.Theco-pyrolysisprocess resulted in a reduction in carbon residue,which could be attributed to the interaction between LDPE and the heavy fractions,particularly resin and asphaltene,present in VR.These findings align with the pyrolysis behaviors exhibited by the four VR fractions.Furthermore,it was observed that the co-pyrolysis process exhibited lower activation energy as the VR ratio increased,indicating a continuous enhancement in the reactivity of the mixed samples during co-pyrolysis.

关键词： co-pyrolysis heavy residual oil polyethylene thermogravimetric analysis synergistic effects

CoSe_(2) nanobelt coupled with CoMoO_(4) nanosheet as efficient electrocatalysts for hydrogen and oxygen evolution reaction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Environmental Science and Ecotechnology 2020年第1期1卷 21-27页

作者： Qiu-sheng Zhou Xin-wen Peng Lin-xin Zhong Run-cang Sun state key laboratory of pulp and paper engineering South China University of TechnologyGuangzhou510641China Center for Lignocellulose Science and engineering Liaoning Key Laboratory Pulp and Paper EngineeringDalian Polytechnic UniversityDalian116034LiaoningChina

Designing non-noble electrocatalysts with low-cost and efficient is crucial to the development of sustainable and clean energy resources.Here,we synthesized a novel S-CoSe_(2)/CoMoO_(4) and O-CoSe_(2)/CoMoO_(4) hybrid electrocatalysts for the HER and OER,respectively.Possibly due to the synergetic chemical coupling effects between CoSe_(2)/DETA and CoMoO_(4),and the introduction of S heteroatom and oxygen vacancy,this hybrid could expose enough active edges,and then promoted the constructed hybrid displayed superior hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalytic performance.The S-CoSe_(2)/CoMoO_(4) sample afforded a current density of 10 mAcm^(-2) at a small overpotential of 177 mV and a small Tafel slope of 54 mV dec^(-1).Moreover,the oxidized CoSe_(2)/CoMoO_(4)(O-CoSe_(2)/CoMoO_(4))also displayed a remarkable catalytic property for OER with a small Tafel slope of 43 mV dec^(-1),as well as excellent stability in 1.0 M KOH.Therefore,this noblemetal-free and highly efficient catalyst enables prospective applications for electrochemical applications.

关键词： Hydrogen evolution Hybrid Synergetic Oxygen evolution Stability

Production of Bamboo Fiber Reinforced Fibrillated Poly(Lactic Acid)(PLA) Material Obtained by a papermaking Process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2015年第2期30卷 429-432页

作者：王瑞彬 YANG Rendang YANG Fei state key laboratory of pulp & paper engineering South China University of Technology

A devised beating process was applied, which enabled the formation of slurry consisting of uniformly dispersed fibrillated polylactic acid（PLA） fibers with bamboo fiber, and the polymer material was obtained by a conventional papermaking process. Owing to the fast dewatering time, good repeatability and the facility to manufacture on a large scale, this process was used. It was revealed that the beaten PLA fiber was overall in machinery extrusion by the results of optical microscope and scanning electron microscope（SEM） observations. The improvement in the tensile index, burst index, tear index and other mechanical properties was considered as a key benefit as a result of adding bamboo fiber.

关键词： bamboo fiber polylactic acid reinforcement papermaking process