Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, k...Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, ketyl and heterocyclic derivatives. Various thermal catalytic cyanation procedures have been devised and scaled up industrially while developing alternative methods are actively pursued. The access to these classes of molecules electrochemically offers greener alternatives to their preparation. The development of electrochemical synthesis of cyano-containing compounds under mild conditions with low energy consumption will imminently become indispensable approaches for industrial production of nitriles. The electrochemical cyanation presents many challenges from the toxicity of cyanide to the development of catalysts and the design of electrochemical cells. Electrochemical cyanation reaction offers promise to conveniently accessing nitriles but still requires efficient electro-catalysts, safe protocols and scale up considerations. This review discusses recent progress in the field of electrochemical synthesis of nitrile compounds placing emphasis on electro-synthetic and electro-catalytic mechanism aspects while making reference to original works to highlight the progress in this area.展开更多
Aminonitriles were prepared efficiently from anodic cyanation of ?amino ester. The effect of different solvents and electrolytes was studied. The other byproducts were analyzed.
A new catalytic decarboxylative cyanation and thiocyanation via a synergistic Na I/Cu catalysis is developed.The photoexcited electron donor-acceptor complex by assembly of Na I,R3P,and N-acyloxy-phthalimide ester(NHP...A new catalytic decarboxylative cyanation and thiocyanation via a synergistic Na I/Cu catalysis is developed.The photoexcited electron donor-acceptor complex by assembly of Na I,R3P,and N-acyloxy-phthalimide ester(NHPI ester)triggers the generation of alkyl radical species,which then engages in Cu-catalyzed radical coupling process.Key to success of this dual catalytic transformation is the reliable charge transfer between I·and Cu(I).This dual catalytic platform can eliminate the use of expensive iridium-based photocatalyst or synthetically elaborate organic dyes.A series of primary,secondary,and tertiary alkyl nitriles and thiocyanates are easily synthesized.Moreover,an asymmetric decarboxylative cyanation by applying a chiral Cu catalyst is also developed to afford chiral nitriles in high enantioselectivity.The mechanistic details and the origin of the high enantioselectivity are further investigated by the mechanistic experiments and the density functional theory calculations.展开更多
The transition-metal-catalyzed migratory functionalization has emerged as a robust protocol for the building of C–C bonds remote from the“initiation”position.However,a similar strategy for the construction of quate...The transition-metal-catalyzed migratory functionalization has emerged as a robust protocol for the building of C–C bonds remote from the“initiation”position.However,a similar strategy for the construction of quaternary carbon centers is still underdeveloped and only a limited number of reports exist.Herein,we report a nickel-catalyzed migratory hydrocyanation of unconjugated dienes to construct remote cyano-substituted quaternary carbon centers.This transformation features exceptional regioselectivity,mild reaction conditions,broad substrate scope and high yields.The synthetic utility of this method has been highlighted by a series of product derivatizations,and the potential of this transformation has been extended to synthesize TRPV1 antagonist and the key intermediate in the total synthesis of quebrachamine.Density functional theory(DFT)studies unveiled that the specific catalytic pocket assumed a significant role in the selective formation of cyano-substituted quaternary carbon centers.展开更多
Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-ec...Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-economic synthesis.Undoubtedly,selectively activating and transforming multiple inert chemical bonds is an even more intriguing and demanding task in synthetic chemistry.However,due to its inherent complexity and extreme challenges,this endeavour is rarely accomplished.We report a copper-mediated complete cleavage and selective transformation of multiple inert chemical bonds of three easily available feedstocks,i.e.,a sp^(2)C—H bond in indoles,three sp^(3)C—H bonds and one C—N bond in a methyl carbon atom in TMEDA,and the C≡N triple bond in CH_(3)CN.This reaction proceeds via tandem carbon and nitrogen atom transfer,and allows for the direct and efficient cyanation of indoles,presenting a simple and direct alternative for synthesizing 3-cyanoindoles.展开更多
Selective 3-cyanation of indoles was achieved under heterogeneous catalysis of Ru(III)-exchanged NaY zeolite (RuY) as a recyclable catalyst, in combination with K4[Fe(CN)6] as a nontoxic, slow cyanide releasing ...Selective 3-cyanation of indoles was achieved under heterogeneous catalysis of Ru(III)-exchanged NaY zeolite (RuY) as a recyclable catalyst, in combination with K4[Fe(CN)6] as a nontoxic, slow cyanide releasing agent. Under the aforementioned conditions, good yields of the desired products were obtained.展开更多
The transition-metal-catalyzed cyanations of aryl halides are among the most used methods for synthesizing aryl nitriles.Despite tremendous advances,cyanating an aryl halide in a facile and benign fashion has generall...The transition-metal-catalyzed cyanations of aryl halides are among the most used methods for synthesizing aryl nitriles.Despite tremendous advances,cyanating an aryl halide in a facile and benign fashion has generally been unsuccessful.The challenge in this significant transformation is the strong affinity of cyanide for metals,which hampers oxidative addition(OD)and reductive elimination(RE)making organometallic catalysis elusive.Herein,we demonstrate for the first time that photoredox-nickel-catalyzed cyanations of aryl halides are readily enabled by visible light,in which Ni(Ⅱ)species are transiently oxidized to Ni(Ⅲ)species,thereby facilitating subsequent cyanide transfer and RE.Using this dual catalysis strategy,we cyanated aryl and alkenyl halides at room temperature in a highly benign manner(30 examples,53-93% yield)by avoiding the use of air-sensitive ligands,Ni(0)precursors,and hypertoxic cyanation reagents,while also limiting excess metal waste.Computational studies were also used to help understand the present transformation.展开更多
With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Liu Guosheng(刘国生)at Shanghai Institute of Organic Chemistry,Chinese Academy of ...With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Liu Guosheng(刘国生)at Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,and Prof.Shannon Stahl at the University of Wisconsin-Madison,discovered a copper-catalyzed radical relay pathway for enantioselective conversion of benzylic C—H bonds展开更多
A ligand-accelerated, branch-selective oxidative cyanation of alkenes has been developed in the presence of catalytic Cu_2O.Both styrenes and aliphatic alkenes with directing groups are well tolerated in this inexpens...A ligand-accelerated, branch-selective oxidative cyanation of alkenes has been developed in the presence of catalytic Cu_2O.Both styrenes and aliphatic alkenes with directing groups are well tolerated in this inexpensive protocol.The mild condition allows for a good tolerance of functional groups, enabling facile access to a diverse array of simple and complex branched vinyl nitriles.The wide synthetic utility of this methodology has been further demonstrated via the efficient scaleup in both batch and continuous flow processes.展开更多
Current studies on the oxidative C--H functionalization of benzylic ethers for C--C forging process dominantly focus on primary ethers. The corresponding reaction of secondary ethers remains underdeveloped. Herein, a ...Current studies on the oxidative C--H functionalization of benzylic ethers for C--C forging process dominantly focus on primary ethers. The corresponding reaction of secondary ethers remains underdeveloped. Herein, a practical and efficient oxidative C--H cyanation of secondary benzylic ethers with TMSCN in the presence of DDQ is described. The metal-free process is well tolerated with a wide variety of electronically varied α-monosubstituted isochromans, facilely furnishing a library of isochromans bearing α-aryl α-cyano substituent patterns for further diversification and bioactive small molecule identification.展开更多
A method for the efficient and reliable synthesis of aryl nitriles via the Cu20-catalyed cross-coupling of aryl boronic acids or esters and TMSCN is presented. A broad range of substrates decorated by electron-rich an...A method for the efficient and reliable synthesis of aryl nitriles via the Cu20-catalyed cross-coupling of aryl boronic acids or esters and TMSCN is presented. A broad range of substrates decorated by electron-rich and defi- cient, sterically very congested, and labile functionalities were tolerated. Moreover, the reaction can proceed under mild conditions at room temperature. These advantages paired with the use of cheap, readily available, and halo- gen-free Cu20 as catalysts make the protocol an appealing option for aryl cyanations.展开更多
A new copper and silver-mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, provid- ing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles.
Aromatic nitriles were synthesized through copper-catalyzed cyanations of aromatic bromides using benzoyl cyanide as the cyanide source.A series of functional groups were tolerated under the reaction conditions to pro...Aromatic nitriles were synthesized through copper-catalyzed cyanations of aromatic bromides using benzoyl cyanide as the cyanide source.A series of functional groups were tolerated under the reaction conditions to provide the products in good yields.Moreover,this protocol avoids using of highly toxic alkali cyanides and expensive palladium catalysts.展开更多
The cyanation-esterification reaction of a-keto esters catalysed by N-heterocyclic carbenes (NHCs) is developed Under the catalysis of 10 tool% 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, aromatic and alipha...The cyanation-esterification reaction of a-keto esters catalysed by N-heterocyclic carbenes (NHCs) is developed Under the catalysis of 10 tool% 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, aromatic and aliphatic a-keto esters reacted with ethyl cyanoformate or acetyl cyanide to produce the corresponding cyano esters with a tetra- substituted carbon center in high yields.展开更多
Covalent triazine-based frameworks(CTFs) are important microporous materials with a wide range of applications.Here,we demonstrate an environmentally benign and economic synthetic pathway to CTFs.The monomers used f...Covalent triazine-based frameworks(CTFs) are important microporous materials with a wide range of applications.Here,we demonstrate an environmentally benign and economic synthetic pathway to CTFs.The monomers used for CTFs,aromatic nitriles,were obtained by cyanation using nontoxic potassium hexacyanoferrate(Ⅱ) in place of commonly used toxic cyanides.Then,the CTFs were synthesized by trimerization of the corresponding cyano monomers in molten zinc chloride.A series of CTFs was synthesized,and the highest Brunauer-Emmett-Teller surface area measured in this series was 2404 m^2/g.Among the synthesized CTFs,CTF_(DCP) exhibited excellent CO_2 adsorption properties,with a CO_2 uptake of 225 mg/g at 0℃.展开更多
In this paper, we described an improved electrochemical method for synthesis of some 1-aryl-2-pyrrolidinecarbonitrile derivatives bearing an electron-withdrawing group (NO2). The electrochemical synthesis of titile ...In this paper, we described an improved electrochemical method for synthesis of some 1-aryl-2-pyrrolidinecarbonitrile derivatives bearing an electron-withdrawing group (NO2). The electrochemical synthesis of titile compounds has been successfully performed in an undivided cell in reasonable yields.展开更多
An efficient heterogeneous Pd catalytic system has been developed, based on immobilization of Pd nanoparticles (PNPs) on a silica-bonded N-propylpiperazine (SBNPP) substrate. The SBNPP substrate effectively stabilizes...An efficient heterogeneous Pd catalytic system has been developed, based on immobilization of Pd nanoparticles (PNPs) on a silica-bonded N-propylpiperazine (SBNPP) substrate. The SBNPP substrate effectively stabilizes the PNPs and improves their stability against aggregation. The catalytic activity of this catalyst was investigated in the cyanation of aryl halides with K4[Fe(CN)6 ] as the cyanide source. The catalyst could be recycled several times without appreciable loss of catalytic activity.展开更多
Aromatics have a broad application in our everyday life ranging from plastics, coatings and fibres, to food and pharmaceuticals. To date the bulk of these aromatics is derived from naphtha-based pet-rochemistry. Howev...Aromatics have a broad application in our everyday life ranging from plastics, coatings and fibres, to food and pharmaceuticals. To date the bulk of these aromatics is derived from naphtha-based pet-rochemistry. However, recent progress in the fermentative production of metabolites using renew-able resources and engineered microbes has enabled the production of bio-precursors, such as 4-amino benzoic acid (pABA) and 2-amino benzoic acid (oABA). In this work we explored the feasibility of Sandmeyer reactions for the conversion of pABA to terephthalic and oABA salicylic acid, providing two very important platform chemicals for the chemical and pharmaceutical industries. We could demonstrate that both acids can be obtained from the amino benzoic acids derived from the shikimate pathway in microbes and plants. Good conversions could be achieved using Sandmeyer reactions at mild conditions with biodegradable reagents and without organic solvents.展开更多
This present study deals with the reinforcement of thermosetting resin blends composed of cyanate ester(CE) and benzoxazine(BOZ) resins with natural hemp fibers(NHFs). These NHFs were initially treated by using a sila...This present study deals with the reinforcement of thermosetting resin blends composed of cyanate ester(CE) and benzoxazine(BOZ) resins with natural hemp fibers(NHFs). These NHFs were initially treated by using a silane coupling agent(SCA) in order to chiefly enhance their distributions as well as adhesions within the CE/BOZ resin matrix,then incorporated with various weight amounts ranging from 5 wt% to 20 wt% with a regular interval of 5 wt%. The obtained results showed that at the maximum treated fiber loading(20 wt%), distinctive enhancements in the mechanical properties in terms of flexural strength and microhardness were obtained. Besides, the thermal stability and glass transition temperature(Tg) were appreciably enhanced and were higher than those of the pure CE/BOZ resin properties. With respect to the astonishing properties of the NHFs, these enhancements could be possibly due to the good dispersion and adhesion of the treated NHFs inside the CE/BOZ resin achieved upon using the SCA. Therefore,we believe herein that these renewable and cheap NHFs have considerable potential to be used as reinfocer materials for CE/BOZ resin composites to be used in various industrial sectors.展开更多
The properties of resin transfer molding(RTM)cyanate ester and its T800 grade carbon fiber composites were studied with the rheometer,differential scanning calorimetry(DSC),FT-IR,dynamic mechanical analyzer(DMA),therm...The properties of resin transfer molding(RTM)cyanate ester and its T800 grade carbon fiber composites were studied with the rheometer,differential scanning calorimetry(DSC),FT-IR,dynamic mechanical analyzer(DMA),thermal gravimetric analysis(TGA),mechanical property testing,and scanning electron microscopy(SEM).The results showed that the temperature of cyanate ester suitable for RTM process was 70℃.Curing process of the resin was 130℃/2 h+160℃/2 h+200℃/2 h+220℃/4 h.Glass transition temperature and heat decomposition temperature of the cured resin are 289℃and 415℃,respectively.Mechanical properties of T800/RTM cyanate composites are 13.5%higher than that of T700/RTM cyanate composites and equal to that of T800/Prepreg cyanate composites.Tg of T800/RTM cyanate composites was proved to be 291℃.Fracture pattern of the composites was flat,which proved excellent interface properties between fiber and resin in this composite.展开更多
基金supports from the National Natural Science Foundation of China(22022204,21633013)the Natural Science Foundation of Jiangsu Province(BK20180248).
文摘Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, ketyl and heterocyclic derivatives. Various thermal catalytic cyanation procedures have been devised and scaled up industrially while developing alternative methods are actively pursued. The access to these classes of molecules electrochemically offers greener alternatives to their preparation. The development of electrochemical synthesis of cyano-containing compounds under mild conditions with low energy consumption will imminently become indispensable approaches for industrial production of nitriles. The electrochemical cyanation presents many challenges from the toxicity of cyanide to the development of catalysts and the design of electrochemical cells. Electrochemical cyanation reaction offers promise to conveniently accessing nitriles but still requires efficient electro-catalysts, safe protocols and scale up considerations. This review discusses recent progress in the field of electrochemical synthesis of nitrile compounds placing emphasis on electro-synthetic and electro-catalytic mechanism aspects while making reference to original works to highlight the progress in this area.
文摘Aminonitriles were prepared efficiently from anodic cyanation of ?amino ester. The effect of different solvents and electrolytes was studied. The other byproducts were analyzed.
基金supported by the National Natural Science Foundation of China(22201087)the National Key R&D Program of China(2022YFA1503200)Guangdong Basic and Applied Basic Research Foundation(2022A1515012507)。
文摘A new catalytic decarboxylative cyanation and thiocyanation via a synergistic Na I/Cu catalysis is developed.The photoexcited electron donor-acceptor complex by assembly of Na I,R3P,and N-acyloxy-phthalimide ester(NHPI ester)triggers the generation of alkyl radical species,which then engages in Cu-catalyzed radical coupling process.Key to success of this dual catalytic transformation is the reliable charge transfer between I·and Cu(I).This dual catalytic platform can eliminate the use of expensive iridium-based photocatalyst or synthetically elaborate organic dyes.A series of primary,secondary,and tertiary alkyl nitriles and thiocyanates are easily synthesized.Moreover,an asymmetric decarboxylative cyanation by applying a chiral Cu catalyst is also developed to afford chiral nitriles in high enantioselectivity.The mechanistic details and the origin of the high enantioselectivity are further investigated by the mechanistic experiments and the density functional theory calculations.
基金the National Natural Science Foundation of China(22278265,U22B20137 and 22203069)the Zhejiang Provincial Natural Science Foundation of China(LR24B020002)+1 种基金the start-up funding from Hangzhou Normal University(4095C50222204165 and 4095C50223204074)the Interdisciplinary Research Project of Hangzhou Normal University(2024JCXK04)for financial support of this research。
文摘The transition-metal-catalyzed migratory functionalization has emerged as a robust protocol for the building of C–C bonds remote from the“initiation”position.However,a similar strategy for the construction of quaternary carbon centers is still underdeveloped and only a limited number of reports exist.Herein,we report a nickel-catalyzed migratory hydrocyanation of unconjugated dienes to construct remote cyano-substituted quaternary carbon centers.This transformation features exceptional regioselectivity,mild reaction conditions,broad substrate scope and high yields.The synthetic utility of this method has been highlighted by a series of product derivatizations,and the potential of this transformation has been extended to synthesize TRPV1 antagonist and the key intermediate in the total synthesis of quebrachamine.Density functional theory(DFT)studies unveiled that the specific catalytic pocket assumed a significant role in the selective formation of cyano-substituted quaternary carbon centers.
基金support from the National Natural Science Foundation of China(Grant Nos.22378106,21878072,21706058,and 22002169)the Natural Science Foundation of Hunan Province(Grant No.2020JJ2011)the China Postdoctoral Science Foundation(No.2019M662774).
文摘Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-economic synthesis.Undoubtedly,selectively activating and transforming multiple inert chemical bonds is an even more intriguing and demanding task in synthetic chemistry.However,due to its inherent complexity and extreme challenges,this endeavour is rarely accomplished.We report a copper-mediated complete cleavage and selective transformation of multiple inert chemical bonds of three easily available feedstocks,i.e.,a sp^(2)C—H bond in indoles,three sp^(3)C—H bonds and one C—N bond in a methyl carbon atom in TMEDA,and the C≡N triple bond in CH_(3)CN.This reaction proceeds via tandem carbon and nitrogen atom transfer,and allows for the direct and efficient cyanation of indoles,presenting a simple and direct alternative for synthesizing 3-cyanoindoles.
文摘Selective 3-cyanation of indoles was achieved under heterogeneous catalysis of Ru(III)-exchanged NaY zeolite (RuY) as a recyclable catalyst, in combination with K4[Fe(CN)6] as a nontoxic, slow cyanide releasing agent. Under the aforementioned conditions, good yields of the desired products were obtained.
基金the National Science Foundation of China(nos.21822103,21820102003,21822303,21772052,21772053,and 91956201)the Program of Introducing Talents of Discipline to Universities of China(111 Program,B17019)the Natural Science Foundation of Hubei Province(no.2017AHB047).
文摘The transition-metal-catalyzed cyanations of aryl halides are among the most used methods for synthesizing aryl nitriles.Despite tremendous advances,cyanating an aryl halide in a facile and benign fashion has generally been unsuccessful.The challenge in this significant transformation is the strong affinity of cyanide for metals,which hampers oxidative addition(OD)and reductive elimination(RE)making organometallic catalysis elusive.Herein,we demonstrate for the first time that photoredox-nickel-catalyzed cyanations of aryl halides are readily enabled by visible light,in which Ni(Ⅱ)species are transiently oxidized to Ni(Ⅲ)species,thereby facilitating subsequent cyanide transfer and RE.Using this dual catalysis strategy,we cyanated aryl and alkenyl halides at room temperature in a highly benign manner(30 examples,53-93% yield)by avoiding the use of air-sensitive ligands,Ni(0)precursors,and hypertoxic cyanation reagents,while also limiting excess metal waste.Computational studies were also used to help understand the present transformation.
文摘With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Liu Guosheng(刘国生)at Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,and Prof.Shannon Stahl at the University of Wisconsin-Madison,discovered a copper-catalyzed radical relay pathway for enantioselective conversion of benzylic C—H bonds
基金supported by the National Natural Science Foundation of China (21702029)the ‘‘Thousand Plan" Youth programthe Shanghai Sailing Program (17YF1400100)
文摘A ligand-accelerated, branch-selective oxidative cyanation of alkenes has been developed in the presence of catalytic Cu_2O.Both styrenes and aliphatic alkenes with directing groups are well tolerated in this inexpensive protocol.The mild condition allows for a good tolerance of functional groups, enabling facile access to a diverse array of simple and complex branched vinyl nitriles.The wide synthetic utility of this methodology has been further demonstrated via the efficient scaleup in both batch and continuous flow processes.
基金financial supported by the National Natural Science Foundation of China(No. 21722204)Fok Ying Tung Education Foundation(No. 151035)the Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University) (No. CHEMR2016-B09)
文摘Current studies on the oxidative C--H functionalization of benzylic ethers for C--C forging process dominantly focus on primary ethers. The corresponding reaction of secondary ethers remains underdeveloped. Herein, a practical and efficient oxidative C--H cyanation of secondary benzylic ethers with TMSCN in the presence of DDQ is described. The metal-free process is well tolerated with a wide variety of electronically varied α-monosubstituted isochromans, facilely furnishing a library of isochromans bearing α-aryl α-cyano substituent patterns for further diversification and bioactive small molecule identification.
文摘A method for the efficient and reliable synthesis of aryl nitriles via the Cu20-catalyed cross-coupling of aryl boronic acids or esters and TMSCN is presented. A broad range of substrates decorated by electron-rich and defi- cient, sterically very congested, and labile functionalities were tolerated. Moreover, the reaction can proceed under mild conditions at room temperature. These advantages paired with the use of cheap, readily available, and halo- gen-free Cu20 as catalysts make the protocol an appealing option for aryl cyanations.
基金We thank the National Natural Science Foundation of China (No. 21272178), the Natural Science Founda- tion of Zhejiang Province (Nos. R4110294 and LY12B02010).
文摘A new copper and silver-mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, provid- ing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles.
基金This project was financially supported by the National Natural Science Foundation of China(No.21302014)the Natural Science Foundation for Colleges and Universities of Jiangsu Province(13KJB150002)the Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology(grant No.BM2012110).
文摘Aromatic nitriles were synthesized through copper-catalyzed cyanations of aromatic bromides using benzoyl cyanide as the cyanide source.A series of functional groups were tolerated under the reaction conditions to provide the products in good yields.Moreover,this protocol avoids using of highly toxic alkali cyanides and expensive palladium catalysts.
文摘The cyanation-esterification reaction of a-keto esters catalysed by N-heterocyclic carbenes (NHCs) is developed Under the catalysis of 10 tool% 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, aromatic and aliphatic a-keto esters reacted with ethyl cyanoformate or acetyl cyanide to produce the corresponding cyano esters with a tetra- substituted carbon center in high yields.
基金supported by the National Natural Science Foundation of China(21373202,21525315)~~
文摘Covalent triazine-based frameworks(CTFs) are important microporous materials with a wide range of applications.Here,we demonstrate an environmentally benign and economic synthetic pathway to CTFs.The monomers used for CTFs,aromatic nitriles,were obtained by cyanation using nontoxic potassium hexacyanoferrate(Ⅱ) in place of commonly used toxic cyanides.Then,the CTFs were synthesized by trimerization of the corresponding cyano monomers in molten zinc chloride.A series of CTFs was synthesized,and the highest Brunauer-Emmett-Teller surface area measured in this series was 2404 m^2/g.Among the synthesized CTFs,CTF_(DCP) exhibited excellent CO_2 adsorption properties,with a CO_2 uptake of 225 mg/g at 0℃.
基金The authors would like to thank the financial support of Beijing TH-UNIS-Insight Co.Ltd.and the National Natural Science Foundation of China (No.20132020) the Ministry of Science and Technology, the Chinese Ministry of Education and Tsinghua University.
文摘In this paper, we described an improved electrochemical method for synthesis of some 1-aryl-2-pyrrolidinecarbonitrile derivatives bearing an electron-withdrawing group (NO2). The electrochemical synthesis of titile compounds has been successfully performed in an undivided cell in reasonable yields.
文摘An efficient heterogeneous Pd catalytic system has been developed, based on immobilization of Pd nanoparticles (PNPs) on a silica-bonded N-propylpiperazine (SBNPP) substrate. The SBNPP substrate effectively stabilizes the PNPs and improves their stability against aggregation. The catalytic activity of this catalyst was investigated in the cyanation of aryl halides with K4[Fe(CN)6 ] as the cyanide source. The catalyst could be recycled several times without appreciable loss of catalytic activity.
文摘Aromatics have a broad application in our everyday life ranging from plastics, coatings and fibres, to food and pharmaceuticals. To date the bulk of these aromatics is derived from naphtha-based pet-rochemistry. However, recent progress in the fermentative production of metabolites using renew-able resources and engineered microbes has enabled the production of bio-precursors, such as 4-amino benzoic acid (pABA) and 2-amino benzoic acid (oABA). In this work we explored the feasibility of Sandmeyer reactions for the conversion of pABA to terephthalic and oABA salicylic acid, providing two very important platform chemicals for the chemical and pharmaceutical industries. We could demonstrate that both acids can be obtained from the amino benzoic acids derived from the shikimate pathway in microbes and plants. Good conversions could be achieved using Sandmeyer reactions at mild conditions with biodegradable reagents and without organic solvents.
基金Supported by the National Natural Science Foundation of China(51773048)the Natural Science Foundation of Heilongjiang Province(E2016025)Fundamental Research Funds for the Central Universities(HEUCFP201724,HEUCFP201791)
文摘This present study deals with the reinforcement of thermosetting resin blends composed of cyanate ester(CE) and benzoxazine(BOZ) resins with natural hemp fibers(NHFs). These NHFs were initially treated by using a silane coupling agent(SCA) in order to chiefly enhance their distributions as well as adhesions within the CE/BOZ resin matrix,then incorporated with various weight amounts ranging from 5 wt% to 20 wt% with a regular interval of 5 wt%. The obtained results showed that at the maximum treated fiber loading(20 wt%), distinctive enhancements in the mechanical properties in terms of flexural strength and microhardness were obtained. Besides, the thermal stability and glass transition temperature(Tg) were appreciably enhanced and were higher than those of the pure CE/BOZ resin properties. With respect to the astonishing properties of the NHFs, these enhancements could be possibly due to the good dispersion and adhesion of the treated NHFs inside the CE/BOZ resin achieved upon using the SCA. Therefore,we believe herein that these renewable and cheap NHFs have considerable potential to be used as reinfocer materials for CE/BOZ resin composites to be used in various industrial sectors.
文摘The properties of resin transfer molding(RTM)cyanate ester and its T800 grade carbon fiber composites were studied with the rheometer,differential scanning calorimetry(DSC),FT-IR,dynamic mechanical analyzer(DMA),thermal gravimetric analysis(TGA),mechanical property testing,and scanning electron microscopy(SEM).The results showed that the temperature of cyanate ester suitable for RTM process was 70℃.Curing process of the resin was 130℃/2 h+160℃/2 h+200℃/2 h+220℃/4 h.Glass transition temperature and heat decomposition temperature of the cured resin are 289℃and 415℃,respectively.Mechanical properties of T800/RTM cyanate composites are 13.5%higher than that of T700/RTM cyanate composites and equal to that of T800/Prepreg cyanate composites.Tg of T800/RTM cyanate composites was proved to be 291℃.Fracture pattern of the composites was flat,which proved excellent interface properties between fiber and resin in this composite.