In this work, esterification of acetic acid and methanol to synthesize methyl acetate in a batch stirred reactor is studied in the temperature range of 305.15–333.15 K. Sulfuric acid is used as the homogeneous cataly...In this work, esterification of acetic acid and methanol to synthesize methyl acetate in a batch stirred reactor is studied in the temperature range of 305.15–333.15 K. Sulfuric acid is used as the homogeneous catalyst with concentrations ranging from 0.0633 mol·L-1to 0.3268 mol·L-1. The feed molar ratio of acetic acid to methanol is varied from 1:1 to 1:4. The influences of temperature, catalyst concentration and reactant concentration on the reaction rate are investigated. A second order kinetic rate equation is used to correlate the experimental data. The forward and backward reaction rate constants and activation energies are determined from the Arrhenius plot.The developed kinetic model is compared with the models in literature. The developed kinetic equation is useful for the simulation of reactive distillation column for the synthesis of methyl acetate.展开更多
Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-elec...Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-electron,multi-step redox reaction associated with sluggish conversion kinetics,subsequently giving rise to a cascade of parasitic issues.In order to smooth reaction kinetics,catalysts are widely introduced to accelerate reaction rate via modulating the energy barrier.Over past decades,a large amount of research has been devoted to the catalyst design and catalytic mechanism exploration,and thus the great progress in electrochemical performance has been realized.Therefore,it is necessary to make a comprehensive review toward key progress in catalyst design and future development pathway.In this review,the basic mechanism of lithium metal batteries is provided along with corresponding advantages and existing challenges detailly described.The main catalysts employed to accelerate cathode reaction with emphasis on their catalytic mechanism are summarized as well.Finally,the rational design and innovative direction toward efficient catalysts are suggested for future application in metal-sulfur/gas battery and beyond.This review is expected to drive and benefit future research on rational catalyst design with multi-parameter synergistic impacts on the activity and stability of next-generation metal battery,thus opening new avenue for sustainable solution to climate change,energy and environmental issues,and the potential industrial economy.展开更多
Non-thermal plasma exhibits unique advan-tages in biomass conversion for the sustainable production of higher-value energy carriers.Different homogeneous catalysts are usually required for plasma-enabled biomass lique...Non-thermal plasma exhibits unique advan-tages in biomass conversion for the sustainable production of higher-value energy carriers.Different homogeneous catalysts are usually required for plasma-enabled biomass liquefaction to achieve time-and energy-efficient conver-sions.However,the effects of such catalysts on the plasma-assisted liquefaction process and of the plasma on those catalysts have not been thoroughly studied.In this study,an electrical discharge plasma is employed to promote the direct liquefaction of sawdust in a mixture of polyethylene glycol 200 and glycerol.Three commonly used chemicals,sulfuric acid,nitric acid and sodium p-toluene sulfate,were selected as catalysts.The effects of the type of catalyst and concentration on the liquefaction yield were examined;further,the roles of the catalysts in the plasma liquefaction process have been discussed.The results showed that the liquefaction yield attains a value of 90%within 5 min when 1%sulfuric acid was employed as the catalyst.Compared with the other catalysts,sulfuric acid presents the highest efficiency for the liquefaction of sawdust.It was observed that hydrogen ions from the catalyst were primarily responsible for the significant thermal effects on the liquefaction system and the generation of large quantities of active species;these effects directly con-tributed to a higher efficacy of the plasma-enabled liquefaction process.展开更多
The reaction mechanisms of diene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of ~1H-NMR, one-and two-dimensions ^(13)C-NMR. Based on the data of above NMR spectra, it is pro...The reaction mechanisms of diene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of ~1H-NMR, one-and two-dimensions ^(13)C-NMR. Based on the data of above NMR spectra, it is proposed that the polymerization reaction proceeds according to the following mechanism: η~4-diene (cis-trans-)and η~3-allyl (syn-anti-).展开更多
This paper represents the interaction of well characterized Lewis base [（Pyr）nCuX]4O2, n = 1 or 2, X = Cl, Br or I, Pyr = pyrrolidine with CO2 as a Lewis acid to produce new series of oxidative coupling and catechol...This paper represents the interaction of well characterized Lewis base [（Pyr）nCuX]4O2, n = 1 or 2, X = Cl, Br or I, Pyr = pyrrolidine with CO2 as a Lewis acid to produce new series of oxidative coupling and catechol oxidase initiators [（Pyr）nCuX]4（CO3）2. These carbonato derivatives are isolated as stable solids. They are easily soluble in aprotic solvents as CH2Cl2 or PhNO2. Cryoscopic measurements support tetranuclear core structure for all of them. Infrared spectra show differences from their oxo analogous in the carbonato domains but those differences did not distinguish between tridentate bridging carbonato and bidentate one. Rate of oxidation of 2,6-dimethylphenol （DMP） by [（Pyr）CuCl]4（CO3）2, supports coordination number six for Cu（Ⅱ） centers in [（Pyr）CuCl]4（CO3）2. In order to fulfill coordination number six, for n = 1, carbonate will act as tridentate while for n = 2, it will act as bidentate, as shown in Scheme 4. Near infrared spectra indicate a [（3 halo） Cu（Ⅱ） charge transfer] for [（Pyr）nCuX]4（CO3）2, n = 1 or 2, X = Cl or Br. Low molecular absorptivities of the maxima at 825 nm and 730 nm for [（Pyr）nCuI]4（CO3）2, n = 1 or 2 with a minimum of high molecular absorptivities at 600 nm, comparing to X= CI or Br analogous, support a step structure for [（Pyr）,Cul]4（CO3）2, as shown in Scheme 5. Cyclic voltammograms for [（Pyr）nCuX]4（CO3）2; n = 1 or 2, X = CI or Br, are irreversible in characters.展开更多
Acid-,base-free depolymerization of poly(ethylene terephthalate)(PET)with ethanol catalyzed by FeCl_(3),FeBr3(1.0–5.0 mol%)gave diethyl terephthalate(DET)and ethylene glycol(EG)exclusively(98–99%,160–180°C),an...Acid-,base-free depolymerization of poly(ethylene terephthalate)(PET)with ethanol catalyzed by FeCl_(3),FeBr3(1.0–5.0 mol%)gave diethyl terephthalate(DET)and ethylene glycol(EG)exclusively(98–99%,160–180°C),and FeCl_(3)showed better catalytic performance in terms of activity.The FeCl_(3)catalyst enabled exclusive,selective depolymerization of PET from textile waste to afford DET(and recovered cotton waste),strongly suggesting the possibility of chemical recycling of cloth waste by the transesterification in this catalysis.展开更多
An efficient green protocol is described for the preparation of highly functionalized piperidines via a one-pot five-component reaction between aromatic aldehydes,anilines andβ-ketoesters in the presence of oxalic ac...An efficient green protocol is described for the preparation of highly functionalized piperidines via a one-pot five-component reaction between aromatic aldehydes,anilines andβ-ketoesters in the presence of oxalic acid dihydrate as catalyst in ethanol at ambient temperature.The structure as well as the relative stereochemistry of these compounds was confirmed by single X-ray crystallographic analysis.展开更多
Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst ...Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCl_2(N=C Bu_2)exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp TiCl_2(X)(X=N=C Bu_2,O-2,6- Pr_2C_6H_3; Cp =Cp,C_5Me_5,indenyl)was related to the calculated coordination ene...展开更多
A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris（hydrogen sulfate） as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The...A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris（hydrogen sulfate） as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The significant features of the present protocol are simplicity, environmentally benign, high yields, no chromatographic separation, and recyclability of the catalyst.展开更多
Formic acid（FA） dehydrogenation has attracted a lot of attentions since it is a convenient method for H_2 production. In this work, we designed a self-supporting fuel cell system, in which H_2 from FA is supplied in...Formic acid（FA） dehydrogenation has attracted a lot of attentions since it is a convenient method for H_2 production. In this work, we designed a self-supporting fuel cell system, in which H_2 from FA is supplied into the fuel cell, and the exhaust heat from the fuel cell supported the FA dehydrogenation. In order to realize the system, we synthesized a highly active and selective homogeneous catalyst Ir Cp＊Cl_2 bpym for FA dehydrogenation. The turnover frequency（TOF） of the catalyst for FA dehydrogenation is as high as7150 h^（-1）at 50°C, and is up to 144,000 h^（-1）at 90°C. The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test. The conversion ratio of FA can achieve 93.2%, and no carbon monoxide is detected in the evolved gas. Therefore, the evolved gas could be applied in the proton exchange membrane fuel cell（PEMFC） directly. This is a potential technology for hydrogen storage and generation. The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.展开更多
Photoredox catalysis has made significant advances in stateof-the-art chemical synthesis,drawing energy from inexhaustible light and enabling various organic transformations to occur under mild reaction conditions.Ove...Photoredox catalysis has made significant advances in stateof-the-art chemical synthesis,drawing energy from inexhaustible light and enabling various organic transformations to occur under mild reaction conditions.Over the past few years,a variety of homogeneous and heterogeneous photocatalysts have been applied in the photoredox catalysis.Heterogeneous photoredox catalysis offers advantages such as easy separation and superior recyclability compared to homogeneous counterparts,although homogenous catalysts are usually associated with higher activities and selectivity.From a practical perspective,an optimal photoredox catalytic system would integrate the advantages of both homogeneous and heterogeneous cases.展开更多
Lithium-sulfur batteries(LSBs)have attracted significant attention due to their high theoretical energy density and low-cost raw materials.However,LSBs still face various challenges in practical applications,particula...Lithium-sulfur batteries(LSBs)have attracted significant attention due to their high theoretical energy density and low-cost raw materials.However,LSBs still face various challenges in practical applications,particularly the shuttle effect,electrode passivation,and slow kinetics.In recent years,trisulfur radicals(TRs),important intermediates in LSBs,have emerged as a promising and beyond-traditional solution to these problems,which serves as a mediated catalyst to improve the electrochemical performance of LSBs.As a system that is inconsistent with the catalytic conversion process discussed in the traditional LSBs,this review focuses on the generation,detection,promotion,and catalytic roles of TRs,especially emphasizing the formation of TRs in solid-state lapis lazuli analogs and discussing the pros and cons of high donor number solvents and/or their co-solvents in stabilizing TRs.Strategies involving homogeneous/heterogeneous catalysts are discussed for increment of TRs and enhancing catalytic reactions in LSBs.Ultimately,given TRs’significant potential as a key factor in enhancing the performance of LSBs,future perspectives and outlooks are provided to guide the further development of TRs in LSBs.This review provides valuable insights into the design of electrolytes and catalysts for increment of TRs,paving the new practical direction and way for advanced LSBs.展开更多
Single-atom catalysis,the catalysis by single-atom catalysts(SACs),has attracted considerable attention in recent years as a new frontier in the heterogeneous catalysis field.SACs have the advantages of both homogeneo...Single-atom catalysis,the catalysis by single-atom catalysts(SACs),has attracted considerable attention in recent years as a new frontier in the heterogeneous catalysis field.SACs have the advantages of both homogeneous catalysts(isolated active sites)and heterogeneous catalysts(stable and easy to separate),and are thus predicted to be able to bridge the homo-and heterogeneous catalysis.This prediction was first experimentally demonstrated in 2016.In this mini-review,we summarize the few homogeneous catalysis progresses reported recently where SACs have exhibited promising application:a)Rh/ZnO and Rh/CoO SAC have been used successfully in hydroformylation of olefin of which the activity are comparable to the homogeneous Wilkinson’s catalyst;b)a Pt/Al2O3 SAC has shown excellent performance in hydrosilylation reaction;and c)M-N-C SACs(M=Fe,Co etc.)have been applied in the activation of C–H bonds.All of these examples suggest that fabrication of suitable SACs could provide a new avenue for the heterogenization of homogeneous catalysts.These pioneering works shed new light on the recognition of single-atom catalysis in bridging the homo-and heterogeneous catalysis.展开更多
A homogeneous catalyst [Cp＊Rh（NH3）（H2O）2]-（3＋） has been found for the clean conversion of methanol and water to hydrogen and carbon dioxide. The simple and easily available reaction steps can circumvent the fo...A homogeneous catalyst [Cp＊Rh（NH3）（H2O）2]-（3＋） has been found for the clean conversion of methanol and water to hydrogen and carbon dioxide. The simple and easily available reaction steps can circumvent the formation of CO, therefore, making it possible to avoid inactivating catalysts and contaminating the hydrogen fuel. Different from conventional reforming method for hydrogen production, no additional alkaline or organic substances are required in this method. Valuable hydrogen can be obtained under ambient pressure at 70 C, corresponding TOF is 83.2 h 1. This is an unprecedented success in reforming methanol to hydrogen. Effects of reaction conditions, such as reaction temperature, initial methanol concentration and the initial p H value of buffer solution on the hydrogen evolution are all systematically investigated. In a certain range, higher reaction temperature will accelerate reaction rate. The slightly acidic condition is conducive to rapid hydrogen production. These findings are of great significance to the present establishment of the carbon-neutral methanol economy.展开更多
The phosphine-functionalized phosphonium-based ionic liquids(dppm-Q, dppe-Q, dppp-Q and dppb-Q) as the bi-functional ligands enable the efficient one-pot tandem hydroformylationeacetalization. It was found that, in dp...The phosphine-functionalized phosphonium-based ionic liquids(dppm-Q, dppe-Q, dppp-Q and dppb-Q) as the bi-functional ligands enable the efficient one-pot tandem hydroformylationeacetalization. It was found that, in dppm-Q, dppe-Q, dppp-Q and dppb-Q, the incorporated phosphino-fragments were responsible for Rh-catalyzed hydroformylation and the phosphoniums were in charge of the subsequent acetalization as the Lewis acid catalysts. Moreover, the diphosphonium-based ionic liquid of dppb-DQ could be applied as a co-solvent to immobilize the Rh/dppb-Q catalytic system with the advantages of the improved catalytic performance, the available catalyst recyclability, and the wide generality for the substrates.展开更多
The transformation of CO_(2)into high value-added product is a promising pathway for utilizing CO_(2).However,the process tends to require harsh reaction conditions owing to CO_(2)chemical inertness.Designing a high e...The transformation of CO_(2)into high value-added product is a promising pathway for utilizing CO_(2).However,the process tends to require harsh reaction conditions owing to CO_(2)chemical inertness.Designing a high efficiency catalytic system with environmentally benign characteristic are important determinants.In this work,protic ionic liquids[TMG][2-OPy]were prepared via one-step neutralization between 1,1,3,3-tetramethylguanidine and 2-hydroxypyridine,applying to the domain of synthesizing quinzoline-2,4(1 H,3H)-diones from CO_(2)and 2-aminobenzontiles without any solvent or metal,achieving the yield of 97%at 90℃for 8 h under atmospheric.A series of substrates with good to acceptable yield were detected,revealing the generality and universality of the catalyst.Furthermore,the system could be facilely reused for at least six runs,retaining the yield of 94%.A preliminary kinetic equation is calculated with the activation energy of 68 kJ·mol^(-1),and a plausible reaction mechanism was put forward.This study highlights that the[TMG][2-OPy]enables to activate CO_(2)carboxylation efficiently.展开更多
An efficient, convenient and environmentally benign one-pot multicomponent reaction for the preparation of pyrimido[4,5-b]quinoline derivatives as biologically, pharmacologically and antibacte- rially active products ...An efficient, convenient and environmentally benign one-pot multicomponent reaction for the preparation of pyrimido[4,5-b]quinoline derivatives as biologically, pharmacologically and antibacte- rially active products has been developed using RuC13.xH20 as a reusable homogenous catalyst. Use of water as a green solvent, purification of products by non-chromatographic methods, reusability of transition metal homogenous catalyst, saving energy by employing multicomponent reactions, short reaction times and high yields, are some of the advantages of this process.展开更多
A series of aromatic aldehydes are turned in to 3,3,6,6-tetramethy1-9-aryl-1,8-dioxooctahydroxanthene derivatives using trich/oroisocyanuric acid （TCCA） as the catalyst.
In this research,a lucunary Keggin structure,[PMo_2W_9O_（39）]^（7-） was selected as an efficient homogenous catalyst for degradation of an azo dye（direct blue 71） and a simple method was developed for degradation...In this research,a lucunary Keggin structure,[PMo_2W_9O_（39）]^（7-） was selected as an efficient homogenous catalyst for degradation of an azo dye（direct blue 71） and a simple method was developed for degradation of DB71.The method is based on the oxidation of azo dye in the presence of a lucunary Keggin form of polyoxometalates,K_7[PMo_2W_9O_（39）]？ 19H_2O,as a homogenous catalyst at room temperature.The reaction is monitored spectrophotometrically by measuring the absorbance of dye atλ=585 nm.Some parameters including concentration of catalyst,concentration of H_2O_2,pH and reaction time were investigated and optimized. Results show that K_7[PMo_2W_9O_（39）]？ 19H_2O is more efficient in the presence of hydrogen peroxide.Degradation of dye in the presence of the catalyst and H_2O_2 could lead to the disappearance approximately 65%of dye after 60 min.But degradation for the same experiment performed in the absence of catalyst or in the absence of H_2O_2 was 22%or 5%respectively.Approximately 87% azo dyes has been eliminated after 90 min in the presence of catalyst,H_2O_2 and optimize conditions（0.6 g/L of K_7[PMo_（2-） W_9O_（39）H_9H_2O,0.08 mol/L hydrogen peroxide and room temperature）.展开更多
Dinuclear metal synergistic catalysis(DMSC)has been evidenced to be effective in enhancing the catalytic activity for CO_(2)reduction.However,the reaction kinetics of CO_(2)reduction is still limited by the local CO_(...Dinuclear metal synergistic catalysis(DMSC)has been evidenced to be effective in enhancing the catalytic activity for CO_(2)reduction.However,the reaction kinetics of CO_(2)reduction is still limited by the local CO_(2)concentration around the dinuclear catalytic centers.Inspired by the structure of carbonic anhydrase,we have designed and synthesized a dinuclear cobalt(Ⅱ)complex with an-OH group.This complex not only exhibits DMSC for CO_(2)reduction but also possesses excellent capture capacity for CO_(2)molecules.Consequently,the complex demonstrates high efficiency for the photocatalytic reduction of CO_(2)to CO,with turnover number reaching as high as 43,400 and a selectivity of 97%.Even in 10%CO_(2),the complex still shows stateof-the-art catalytic activity.The results of experiments and theoretical calculations reveal that besides the DMSC contributing to the enhanced catalytic activity,the-OH group in the dinuclear cobalt(Ⅱ)complex facilitates the capture of CO_(2)by the formation of HCO_(3)^(-)intermediates,thereby enhancing the affinity towards CO_(2)and boosting the catalytic activity for CO_(2)-to-CO conversion.展开更多
文摘In this work, esterification of acetic acid and methanol to synthesize methyl acetate in a batch stirred reactor is studied in the temperature range of 305.15–333.15 K. Sulfuric acid is used as the homogeneous catalyst with concentrations ranging from 0.0633 mol·L-1to 0.3268 mol·L-1. The feed molar ratio of acetic acid to methanol is varied from 1:1 to 1:4. The influences of temperature, catalyst concentration and reactant concentration on the reaction rate are investigated. A second order kinetic rate equation is used to correlate the experimental data. The forward and backward reaction rate constants and activation energies are determined from the Arrhenius plot.The developed kinetic model is compared with the models in literature. The developed kinetic equation is useful for the simulation of reactive distillation column for the synthesis of methyl acetate.
基金supported by the National Natural Science Foundation of China(52272194)Liaoning Revitalization Talents Program(XLYC2007155)。
文摘Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-electron,multi-step redox reaction associated with sluggish conversion kinetics,subsequently giving rise to a cascade of parasitic issues.In order to smooth reaction kinetics,catalysts are widely introduced to accelerate reaction rate via modulating the energy barrier.Over past decades,a large amount of research has been devoted to the catalyst design and catalytic mechanism exploration,and thus the great progress in electrochemical performance has been realized.Therefore,it is necessary to make a comprehensive review toward key progress in catalyst design and future development pathway.In this review,the basic mechanism of lithium metal batteries is provided along with corresponding advantages and existing challenges detailly described.The main catalysts employed to accelerate cathode reaction with emphasis on their catalytic mechanism are summarized as well.Finally,the rational design and innovative direction toward efficient catalysts are suggested for future application in metal-sulfur/gas battery and beyond.This review is expected to drive and benefit future research on rational catalyst design with multi-parameter synergistic impacts on the activity and stability of next-generation metal battery,thus opening new avenue for sustainable solution to climate change,energy and environmental issues,and the potential industrial economy.
基金This work was supported by the Foundation of Key Laboratory of Biomass Chemical Engineering of Ministry of Education,China(Zhejiang University,No.2018BCE006)We are also grateful to the Australian Research Council for their partial support.
文摘Non-thermal plasma exhibits unique advan-tages in biomass conversion for the sustainable production of higher-value energy carriers.Different homogeneous catalysts are usually required for plasma-enabled biomass liquefaction to achieve time-and energy-efficient conver-sions.However,the effects of such catalysts on the plasma-assisted liquefaction process and of the plasma on those catalysts have not been thoroughly studied.In this study,an electrical discharge plasma is employed to promote the direct liquefaction of sawdust in a mixture of polyethylene glycol 200 and glycerol.Three commonly used chemicals,sulfuric acid,nitric acid and sodium p-toluene sulfate,were selected as catalysts.The effects of the type of catalyst and concentration on the liquefaction yield were examined;further,the roles of the catalysts in the plasma liquefaction process have been discussed.The results showed that the liquefaction yield attains a value of 90%within 5 min when 1%sulfuric acid was employed as the catalyst.Compared with the other catalysts,sulfuric acid presents the highest efficiency for the liquefaction of sawdust.It was observed that hydrogen ions from the catalyst were primarily responsible for the significant thermal effects on the liquefaction system and the generation of large quantities of active species;these effects directly con-tributed to a higher efficacy of the plasma-enabled liquefaction process.
基金The Project is supported by "Laboratory of Physics & Chemistry, Academia Sinica" and "National Natural Science Foundation of China"
文摘The reaction mechanisms of diene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of ~1H-NMR, one-and two-dimensions ^(13)C-NMR. Based on the data of above NMR spectra, it is proposed that the polymerization reaction proceeds according to the following mechanism: η~4-diene (cis-trans-)and η~3-allyl (syn-anti-).
文摘This paper represents the interaction of well characterized Lewis base [（Pyr）nCuX]4O2, n = 1 or 2, X = Cl, Br or I, Pyr = pyrrolidine with CO2 as a Lewis acid to produce new series of oxidative coupling and catechol oxidase initiators [（Pyr）nCuX]4（CO3）2. These carbonato derivatives are isolated as stable solids. They are easily soluble in aprotic solvents as CH2Cl2 or PhNO2. Cryoscopic measurements support tetranuclear core structure for all of them. Infrared spectra show differences from their oxo analogous in the carbonato domains but those differences did not distinguish between tridentate bridging carbonato and bidentate one. Rate of oxidation of 2,6-dimethylphenol （DMP） by [（Pyr）CuCl]4（CO3）2, supports coordination number six for Cu（Ⅱ） centers in [（Pyr）CuCl]4（CO3）2. In order to fulfill coordination number six, for n = 1, carbonate will act as tridentate while for n = 2, it will act as bidentate, as shown in Scheme 4. Near infrared spectra indicate a [（3 halo） Cu（Ⅱ） charge transfer] for [（Pyr）nCuX]4（CO3）2, n = 1 or 2, X = Cl or Br. Low molecular absorptivities of the maxima at 825 nm and 730 nm for [（Pyr）nCuI]4（CO3）2, n = 1 or 2 with a minimum of high molecular absorptivities at 600 nm, comparing to X= CI or Br analogous, support a step structure for [（Pyr）,Cul]4（CO3）2, as shown in Scheme 5. Cyclic voltammograms for [（Pyr）nCuX]4（CO3）2; n = 1 or 2, X = CI or Br, are irreversible in characters.
基金supported by JST-CREST(grant number JPMJCR21L5)the authors express their thanks to Ms.Yuriko Ohki and Mr.Asahi Tanaka(Tokyo Metropolitan University)for some technical support。
文摘Acid-,base-free depolymerization of poly(ethylene terephthalate)(PET)with ethanol catalyzed by FeCl_(3),FeBr3(1.0–5.0 mol%)gave diethyl terephthalate(DET)and ethylene glycol(EG)exclusively(98–99%,160–180°C),and FeCl_(3)showed better catalytic performance in terms of activity.The FeCl_(3)catalyst enabled exclusive,selective depolymerization of PET from textile waste to afford DET(and recovered cotton waste),strongly suggesting the possibility of chemical recycling of cloth waste by the transesterification in this catalysis.
基金support from the Research Council of the University of Sistan and Baluchestanthe Australian National University
文摘An efficient green protocol is described for the preparation of highly functionalized piperidines via a one-pot five-component reaction between aromatic aldehydes,anilines andβ-ketoesters in the presence of oxalic acid dihydrate as catalyst in ethanol at ambient temperature.The structure as well as the relative stereochemistry of these compounds was confirmed by single X-ray crystallographic analysis.
基金Grant-in-Aid for Scientific Research(B)from the Japan Society for the Promotion of Science(JSPS,No.18350055).
文摘Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCl_2(N=C Bu_2)exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp TiCl_2(X)(X=N=C Bu_2,O-2,6- Pr_2C_6H_3; Cp =Cp,C_5Me_5,indenyl)was related to the calculated coordination ene...
基金Firoozabad University Research Council for the partialfinancial support
文摘A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris（hydrogen sulfate） as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The significant features of the present protocol are simplicity, environmentally benign, high yields, no chromatographic separation, and recyclability of the catalyst.
基金financial support granted by Ministry of Science and Technology of China(Nos.2016YFE0105700,2016YFA0200700)the National Natural Science Foundation of China(Nos.21373264,21573275)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20150362)Suzhou Institute of Nano-tech and Nano-bionics(No.Y3AAA11004)Thousand Youth Talents Plan(No.Y3BQA11001)
文摘Formic acid（FA） dehydrogenation has attracted a lot of attentions since it is a convenient method for H_2 production. In this work, we designed a self-supporting fuel cell system, in which H_2 from FA is supplied into the fuel cell, and the exhaust heat from the fuel cell supported the FA dehydrogenation. In order to realize the system, we synthesized a highly active and selective homogeneous catalyst Ir Cp＊Cl_2 bpym for FA dehydrogenation. The turnover frequency（TOF） of the catalyst for FA dehydrogenation is as high as7150 h^（-1）at 50°C, and is up to 144,000 h^（-1）at 90°C. The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test. The conversion ratio of FA can achieve 93.2%, and no carbon monoxide is detected in the evolved gas. Therefore, the evolved gas could be applied in the proton exchange membrane fuel cell（PEMFC） directly. This is a potential technology for hydrogen storage and generation. The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.
基金the National Natural Science Foundation of China(No.22271060),The Department of Chemistry at Fudan University and College of Chemistry and Chemical Engineering at Ningxia University is gratefully acknowledged.
文摘Photoredox catalysis has made significant advances in stateof-the-art chemical synthesis,drawing energy from inexhaustible light and enabling various organic transformations to occur under mild reaction conditions.Over the past few years,a variety of homogeneous and heterogeneous photocatalysts have been applied in the photoredox catalysis.Heterogeneous photoredox catalysis offers advantages such as easy separation and superior recyclability compared to homogeneous counterparts,although homogenous catalysts are usually associated with higher activities and selectivity.From a practical perspective,an optimal photoredox catalytic system would integrate the advantages of both homogeneous and heterogeneous cases.
基金supported by the National Key Research and Development Program of China(No.2021YFF0500600)National Natural Science Foundation of China(No.22309165),Natural Science Foundation of Henan Province(No.232300420296)Key Scientific Research Project Plan of Henan Provincial Higher Education Institutions(No.25B430006).
文摘Lithium-sulfur batteries(LSBs)have attracted significant attention due to their high theoretical energy density and low-cost raw materials.However,LSBs still face various challenges in practical applications,particularly the shuttle effect,electrode passivation,and slow kinetics.In recent years,trisulfur radicals(TRs),important intermediates in LSBs,have emerged as a promising and beyond-traditional solution to these problems,which serves as a mediated catalyst to improve the electrochemical performance of LSBs.As a system that is inconsistent with the catalytic conversion process discussed in the traditional LSBs,this review focuses on the generation,detection,promotion,and catalytic roles of TRs,especially emphasizing the formation of TRs in solid-state lapis lazuli analogs and discussing the pros and cons of high donor number solvents and/or their co-solvents in stabilizing TRs.Strategies involving homogeneous/heterogeneous catalysts are discussed for increment of TRs and enhancing catalytic reactions in LSBs.Ultimately,given TRs’significant potential as a key factor in enhancing the performance of LSBs,future perspectives and outlooks are provided to guide the further development of TRs in LSBs.This review provides valuable insights into the design of electrolytes and catalysts for increment of TRs,paving the new practical direction and way for advanced LSBs.
基金supported by National Natural Science Foundation of China(21606222,21776270)Postdoctoral Science Foundation(2017M621170,2016M601350)~~
文摘Single-atom catalysis,the catalysis by single-atom catalysts(SACs),has attracted considerable attention in recent years as a new frontier in the heterogeneous catalysis field.SACs have the advantages of both homogeneous catalysts(isolated active sites)and heterogeneous catalysts(stable and easy to separate),and are thus predicted to be able to bridge the homo-and heterogeneous catalysis.This prediction was first experimentally demonstrated in 2016.In this mini-review,we summarize the few homogeneous catalysis progresses reported recently where SACs have exhibited promising application:a)Rh/ZnO and Rh/CoO SAC have been used successfully in hydroformylation of olefin of which the activity are comparable to the homogeneous Wilkinson’s catalyst;b)a Pt/Al2O3 SAC has shown excellent performance in hydrosilylation reaction;and c)M-N-C SACs(M=Fe,Co etc.)have been applied in the activation of C–H bonds.All of these examples suggest that fabrication of suitable SACs could provide a new avenue for the heterogenization of homogeneous catalysts.These pioneering works shed new light on the recognition of single-atom catalysis in bridging the homo-and heterogeneous catalysis.
基金financial support granted by Ministry of Science and Technology of the People's Republic of China(Nos.2016YFA0200700 and 2016YFE0105700)the National Natural Science Foundation of China(Nos.21373264 and 21573275)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20150362)Suzhou Institute of Nano-tech and Nanobionics(No.Y3AAA11004)Thousand Youth Talents Plan(No.Y3BQA11001)
文摘A homogeneous catalyst [Cp＊Rh（NH3）（H2O）2]-（3＋） has been found for the clean conversion of methanol and water to hydrogen and carbon dioxide. The simple and easily available reaction steps can circumvent the formation of CO, therefore, making it possible to avoid inactivating catalysts and contaminating the hydrogen fuel. Different from conventional reforming method for hydrogen production, no additional alkaline or organic substances are required in this method. Valuable hydrogen can be obtained under ambient pressure at 70 C, corresponding TOF is 83.2 h 1. This is an unprecedented success in reforming methanol to hydrogen. Effects of reaction conditions, such as reaction temperature, initial methanol concentration and the initial p H value of buffer solution on the hydrogen evolution are all systematically investigated. In a certain range, higher reaction temperature will accelerate reaction rate. The slightly acidic condition is conducive to rapid hydrogen production. These findings are of great significance to the present establishment of the carbon-neutral methanol economy.
基金financially supported by the National Natural Science Foundation of China(Nos.21673077,21473058,and 21273077)
文摘The phosphine-functionalized phosphonium-based ionic liquids(dppm-Q, dppe-Q, dppp-Q and dppb-Q) as the bi-functional ligands enable the efficient one-pot tandem hydroformylationeacetalization. It was found that, in dppm-Q, dppe-Q, dppp-Q and dppb-Q, the incorporated phosphino-fragments were responsible for Rh-catalyzed hydroformylation and the phosphoniums were in charge of the subsequent acetalization as the Lewis acid catalysts. Moreover, the diphosphonium-based ionic liquid of dppb-DQ could be applied as a co-solvent to immobilize the Rh/dppb-Q catalytic system with the advantages of the improved catalytic performance, the available catalyst recyclability, and the wide generality for the substrates.
基金supported by the National Natural Science Foundation of China(22278202)the Natural Science Foundation of Jiangsu Province(BM2018007.BK20210185).
文摘The transformation of CO_(2)into high value-added product is a promising pathway for utilizing CO_(2).However,the process tends to require harsh reaction conditions owing to CO_(2)chemical inertness.Designing a high efficiency catalytic system with environmentally benign characteristic are important determinants.In this work,protic ionic liquids[TMG][2-OPy]were prepared via one-step neutralization between 1,1,3,3-tetramethylguanidine and 2-hydroxypyridine,applying to the domain of synthesizing quinzoline-2,4(1 H,3H)-diones from CO_(2)and 2-aminobenzontiles without any solvent or metal,achieving the yield of 97%at 90℃for 8 h under atmospheric.A series of substrates with good to acceptable yield were detected,revealing the generality and universality of the catalyst.Furthermore,the system could be facilely reused for at least six runs,retaining the yield of 94%.A preliminary kinetic equation is calculated with the activation energy of 68 kJ·mol^(-1),and a plausible reaction mechanism was put forward.This study highlights that the[TMG][2-OPy]enables to activate CO_(2)carboxylation efficiently.
基金the Research Council of University of Guilan for partial support
文摘An efficient, convenient and environmentally benign one-pot multicomponent reaction for the preparation of pyrimido[4,5-b]quinoline derivatives as biologically, pharmacologically and antibacte- rially active products has been developed using RuC13.xH20 as a reusable homogenous catalyst. Use of water as a green solvent, purification of products by non-chromatographic methods, reusability of transition metal homogenous catalyst, saving energy by employing multicomponent reactions, short reaction times and high yields, are some of the advantages of this process.
基金the faculty of chemistry of Tarbiat Moallem University for supporting this work
文摘A series of aromatic aldehydes are turned in to 3,3,6,6-tetramethy1-9-aryl-1,8-dioxooctahydroxanthene derivatives using trich/oroisocyanuric acid （TCCA） as the catalyst.
基金Supported by the Islamic Azad University Yazd Branch
文摘In this research,a lucunary Keggin structure,[PMo_2W_9O_（39）]^（7-） was selected as an efficient homogenous catalyst for degradation of an azo dye（direct blue 71） and a simple method was developed for degradation of DB71.The method is based on the oxidation of azo dye in the presence of a lucunary Keggin form of polyoxometalates,K_7[PMo_2W_9O_（39）]？ 19H_2O,as a homogenous catalyst at room temperature.The reaction is monitored spectrophotometrically by measuring the absorbance of dye atλ=585 nm.Some parameters including concentration of catalyst,concentration of H_2O_2,pH and reaction time were investigated and optimized. Results show that K_7[PMo_2W_9O_（39）]？ 19H_2O is more efficient in the presence of hydrogen peroxide.Degradation of dye in the presence of the catalyst and H_2O_2 could lead to the disappearance approximately 65%of dye after 60 min.But degradation for the same experiment performed in the absence of catalyst or in the absence of H_2O_2 was 22%or 5%respectively.Approximately 87% azo dyes has been eliminated after 90 min in the presence of catalyst,H_2O_2 and optimize conditions（0.6 g/L of K_7[PMo_（2-） W_9O_（39）H_9H_2O,0.08 mol/L hydrogen peroxide and room temperature）.
基金supported by the National Key R&D Program of China (2022YFA1502902)the National Natural Science Foundation of China (22271218,22071182,22201209,and 21931007)。
文摘Dinuclear metal synergistic catalysis(DMSC)has been evidenced to be effective in enhancing the catalytic activity for CO_(2)reduction.However,the reaction kinetics of CO_(2)reduction is still limited by the local CO_(2)concentration around the dinuclear catalytic centers.Inspired by the structure of carbonic anhydrase,we have designed and synthesized a dinuclear cobalt(Ⅱ)complex with an-OH group.This complex not only exhibits DMSC for CO_(2)reduction but also possesses excellent capture capacity for CO_(2)molecules.Consequently,the complex demonstrates high efficiency for the photocatalytic reduction of CO_(2)to CO,with turnover number reaching as high as 43,400 and a selectivity of 97%.Even in 10%CO_(2),the complex still shows stateof-the-art catalytic activity.The results of experiments and theoretical calculations reveal that besides the DMSC contributing to the enhanced catalytic activity,the-OH group in the dinuclear cobalt(Ⅱ)complex facilitates the capture of CO_(2)by the formation of HCO_(3)^(-)intermediates,thereby enhancing the affinity towards CO_(2)and boosting the catalytic activity for CO_(2)-to-CO conversion.
