In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)_5CH_3I and W(CO)_4I_2 produced from UV laser photolysis of W (CO)_6 in CH_3I, I_2—C_6H_...In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)_5CH_3I and W(CO)_4I_2 produced from UV laser photolysis of W (CO)_6 in CH_3I, I_2—C_6H_6 and CHI_3—C_6H_6 respectively was studied. The effects of laser energy, laser irradiation time and lifetime of catalyst on the polymerization of phenylacetylene were discussed. The photoproducts of W (CO)_6 in CH_3I, I2—C_6H_6 and CHI_3—C_6I_6 were determined by IR spectra. The structures of polyphenylacetylene obtained by W (CO)_5CH_3I and W (CO)_4I_2 catalysts were characterized by IR spectra and ~1H NMR spectra.展开更多
In the last years, biodiesel production has been on a steady increase due to it is renewable and biodegradable fuel. The process to obtain biodiesel can be carried out using different raw materials. It is conlmonly pe...In the last years, biodiesel production has been on a steady increase due to it is renewable and biodegradable fuel. The process to obtain biodiesel can be carried out using different raw materials. It is conlmonly performed by transesterification reaction of vegetable oils with methanol and using a homogeneous or heterogeneous catalyst. This work seeks to compare the results produced in transesterification of wasted cooking oil and chicken fat by homogeneous catalysis with NaOH. Due to in each case triglyceride comes from different raw materials, operation conditions differ slightly, which is more evident in the values used for the temperature. For chicken fat was used temperature variations between 35 ℃ and 55 ℃, varying catalyst in percentages between 0.3% and 0.7% with a molar ratio 6:1 in all cases and a reaction time of I h. Likewise, the conditions used in the tmnsesterification process of waste cooking oil were temperature between 50 ℃ and 60 ℃ with a molar ratio 6/1 and 9/1 for alcohol and oil, and catalyst percentage between 0.5% and 0.7% by weight. The yields obtained were between 78% and 94%, or 83% and 95%, for chicken fat and wasted cooking oil, respectively.展开更多
Microfluidics has received extensive attention due to its ability to rapidly prepare a large number of microdroplets with controlled sizes and defined morphologies.In addition to having large surface areas and control...Microfluidics has received extensive attention due to its ability to rapidly prepare a large number of microdroplets with controlled sizes and defined morphologies.In addition to having large surface areas and controllable confinement environments,these prepared microdroplets can be used as analytical detection devices to screen and optimize various kinetic parameters.This review summarizes recent advances in the microfluidic control of droplet-based catalytic reactions and discusses the role of these droplets in both homogeneous and heterogeneous catalyzes and in the catalysis of macromolecular biological enzymes in water-in-oil and oil-in-oil environments.Additionally,the existing problems and future development directions of droplets in catalysis are highlighted to promote the development of catalytic reactions in droplet media and provide guidance for the high-throughput screening of catalysts and the directed evolution of biological enzymes.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
As a follow-up to our previous study on the transesterification of Nigerian Jatropha curcas oil into Biodiesel using homogenous catalysis, kinetic study of the reaction is hereby presented. The kinetic study revealed ...As a follow-up to our previous study on the transesterification of Nigerian Jatropha curcas oil into Biodiesel using homogenous catalysis, kinetic study of the reaction is hereby presented. The kinetic study revealed that the rate of formation of biodiesel can be increased by increasing reaction temperature and oil to alcohol molar ratio. The optimum reaction condition was established to be 60°C (reaction temperature) and 1:6 (oil to alcohol ratio). Accordingly, the highest biodiesel yield obtained from homogeneously catalyzed transesterification of Nigerian Jatropha curcas (JC) oil into Biodiesel was 86.61% w/w at 60°C with oil to alcohol ratio of 1:6. Furthermore, kinetic study also revealed that conversion of triglyceride to diglyceride was the rate determining step (RDS) of the overall reaction because activation energy of its backward reaction is lower than that of the forward reaction, indicating unstable nature and higher potential energy of the diglyceride in comparison to the triglyceride.展开更多
Although the combination of electrochemistry and homogeneous catalysis has proven to be a powerful strategy for achieving a diverse array of novel transformations,some challenges such as controlling the diffusion of c...Although the combination of electrochemistry and homogeneous catalysis has proven to be a powerful strategy for achieving a diverse array of novel transformations,some challenges such as controlling the diffusion of catalyst-related species and the instability of catalysts at electrodes remain to be overcome.Herein,we review recent advances in electrochemical homogeneous catalysis,focusing on electrochemical noble-transition-metal catalysis,photoelectrochemical catalysis,and electrochemical enantioselective catalysis.The topics discussed include:(1)how the noblemetal catalystworks in the presence of cathodic hydrogen evolution,(2)how the photocatalyst gets enhanced redox property,and(3)how the enantioselectivity is regulated in a catalytic electrochemical reaction.展开更多
Asymmetric hydrogenation of all-carbon aromatics is still a long-standing challenge in the area of asymmetric catalysis.To date,asymmetric(transfer)hydrogenation of naphthols and phenols remains unexplored.Here,we des...Asymmetric hydrogenation of all-carbon aromatics is still a long-standing challenge in the area of asymmetric catalysis.To date,asymmetric(transfer)hydrogenation of naphthols and phenols remains unexplored.Here,we describe a new strategy for such asymmetric transformation via a bimetallic cooperative heterogeneous and homogeneous catalysis.By using HCOONa as the hydrogen source,various naphthols and phenols were partially hydrogenated in HFIP catalyzed by commercial Pd/C catalyst to give ketone intermediates.Further adding the second chiral Ru-tethered-TsDPEN catalyst and MeOH realized the asymmetric reduction of the resulting ketones in a one-pot manner,furnishing chiral alcohols with good to excellent enantioselectivity(up to 99%ee).The use of HFIP is crucial for suppressing ketone over-reduction via heterogeneous catalysis.More importantly,tandem asymmetric transfer hydrogenation of naphthols was also achieved by tuning the volume ratio of mixed HFIP/MeOH solvent,affording chiral 1,2,3,4-tetrahyronaphthols with excellent enantioselectivity but relatively low yield and limited substrate scope.展开更多
Cyclopalladated ferrocenylimines as a novel kind of highly efficient palladium catalyst precursors, which are air-stable and easy to handle, have been successfully applied in a wide variety of catalytic reactions rang...Cyclopalladated ferrocenylimines as a novel kind of highly efficient palladium catalyst precursors, which are air-stable and easy to handle, have been successfully applied in a wide variety of catalytic reactions ranging from classical reactions, such as Heck, Suzuki, Sonogashira and Buchwald-Hartwig couplings, to cyanation, addition reactions of arylboronic acids, and coupling reactions involving terminal alkynes. The preliminary achievements regarding their applications to homogeneous catalysis are concisely described herein.展开更多
Over the past two decades,homogeneous gold catalysis has experienced exponential development and contributed a plethora of highly valuable synthetic methods to the synthetic toolbox.Metal–ligand cooperative catalysis...Over the past two decades,homogeneous gold catalysis has experienced exponential development and contributed a plethora of highly valuable synthetic methods to the synthetic toolbox.Metal–ligand cooperative catalysis is a versatile strategy for achieving highly efficient and/or novel catalysis but has seldom been explored in gold chemistry.This minireview summarizes the progress we have made in developing remotely functionalized biaryl-2-ylphosphine ligands and employing them in cooperative gold catalysis that achieves excellent catalytic efficiency or realizes previously unknown reactivities.This approach also provides new venues for implementing asymmetric gold catalysis.展开更多
1 Results Significant progress has been made in recent years in developing efficient, atom economical catalytic reactions of potential applicability to the pharmaceutical, petrochemical, and commodity chemical busines...1 Results Significant progress has been made in recent years in developing efficient, atom economical catalytic reactions of potential applicability to the pharmaceutical, petrochemical, and commodity chemical business sectors. In some cases, homogeneous catalytic processes offer advantages, but in others the use of heterogenized homogeneous catalysis provides a competitive advantage concerning recyclability and catalyst recovery. This presentation will consider new approaches to cyclization reactions a...展开更多
Photoelectrochemical(PEC)organic transformation at the anode coupled with cathodic H_(2) generation is a potentially rewarding strategy for efficient solar energy utilization.Nevertheless,achieving the full conversion ...Photoelectrochemical(PEC)organic transformation at the anode coupled with cathodic H_(2) generation is a potentially rewarding strategy for efficient solar energy utilization.Nevertheless,achieving the full conversion of organic substrates with exceptional product selectivity remains a formidable hurdle in the context of heterogeneous catalysis at the solid/liquid interface.Here,we put forward a quasi-homogeneous catalysis concept by using the reactive oxygen species(ROS),such as·OH,H_(2)O_(2) and SO_(4)^(2-),as a charge transfer mediator instead of direct heterogeneous catalysis at the solid/liquid interface.In the context of glycerol oxidation,all ROS exhibited a preference forfirst-order reaction kinetics.These ROS,however,showcased distinct oxidation mechanisms,offering a range of advantages such as100%conversion ratios and theflexibility to tune the resulting products.Glycerol oxidative formic acid with Faradaic efficiency(FE)of 81.2%was realized by the H_(2)O_(2) and·OH,while SO_(4)^(2-)was preferably for glycerol conversion to C3 products like glyceraldehyde and dihydroxyacetone with a total FE of about 80%.Strikingly,the oxidative coupling of methane to ethanol was successfully achieved in our quasi-homogeneous system,yielding a remarkable production rate of 12.27 lmol h^(-1) and an impressive selectivity of 92.7%.This study is anticipated to pave the way for novel approaches in steering solar-driven organic conversions by manipulating ROS to attain desired products and conversion ratios.展开更多
Photocatalytic water oxidation reaction by transition metal complexes remains a challenge because of their poor stability under irradiation,especially for earth-abundant metal catalysts.In this regard,ironbased water ...Photocatalytic water oxidation reaction by transition metal complexes remains a challenge because of their poor stability under irradiation,especially for earth-abundant metal catalysts.In this regard,ironbased water oxidation catalysts are prone to hydrolysis and/or dissociate the ligands to form nanoparticles under a real catalytic condition.Herein,we describe a unique hexa-coordinated catalyst 1[Fe^(II)(Py_(3)tacn)Cl_(2)]and its reference 2[Fe^(II)(PhPy_(2)tacn)Cl_(2)]with a dangling pyridyl ligand and a phenyl group,respectively.We anticipated that the dynamically open and close coordination behaviors of the pyridyl ligand enabled balance of the reactivity and stability of catalyst 1.To our delight,the“open form”of catalyst 1 provided a free coordination site,and the“close form”guaranteed its molecular integrity,resulting in a water oxidation reaction with high efficiency and robustness.The turnover number and turnover frequency values of 2332 and 60 s^(−1)are the highest known to date among iron-based homogeneous water oxidation systems under visible light irradiation.展开更多
文摘In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)_5CH_3I and W(CO)_4I_2 produced from UV laser photolysis of W (CO)_6 in CH_3I, I_2—C_6H_6 and CHI_3—C_6H_6 respectively was studied. The effects of laser energy, laser irradiation time and lifetime of catalyst on the polymerization of phenylacetylene were discussed. The photoproducts of W (CO)_6 in CH_3I, I2—C_6H_6 and CHI_3—C_6I_6 were determined by IR spectra. The structures of polyphenylacetylene obtained by W (CO)_5CH_3I and W (CO)_4I_2 catalysts were characterized by IR spectra and ~1H NMR spectra.
文摘In the last years, biodiesel production has been on a steady increase due to it is renewable and biodegradable fuel. The process to obtain biodiesel can be carried out using different raw materials. It is conlmonly performed by transesterification reaction of vegetable oils with methanol and using a homogeneous or heterogeneous catalyst. This work seeks to compare the results produced in transesterification of wasted cooking oil and chicken fat by homogeneous catalysis with NaOH. Due to in each case triglyceride comes from different raw materials, operation conditions differ slightly, which is more evident in the values used for the temperature. For chicken fat was used temperature variations between 35 ℃ and 55 ℃, varying catalyst in percentages between 0.3% and 0.7% with a molar ratio 6:1 in all cases and a reaction time of I h. Likewise, the conditions used in the tmnsesterification process of waste cooking oil were temperature between 50 ℃ and 60 ℃ with a molar ratio 6/1 and 9/1 for alcohol and oil, and catalyst percentage between 0.5% and 0.7% by weight. The yields obtained were between 78% and 94%, or 83% and 95%, for chicken fat and wasted cooking oil, respectively.
基金supported by the National Key R&D Program of China(2021YFA1501600)National Nature Science Foundation of China(Nos.22107028 and 22103062)+3 种基金Program of Shanghai Outstanding Academic Leaders(No.21XD1421200)Science and Technology Commission of Shanghai Municipality(22JC1403900)Shanghai Pujiang Program(No.22PJ1402800)the Fundamental Research Funds for the Central Universities.
文摘Microfluidics has received extensive attention due to its ability to rapidly prepare a large number of microdroplets with controlled sizes and defined morphologies.In addition to having large surface areas and controllable confinement environments,these prepared microdroplets can be used as analytical detection devices to screen and optimize various kinetic parameters.This review summarizes recent advances in the microfluidic control of droplet-based catalytic reactions and discusses the role of these droplets in both homogeneous and heterogeneous catalyzes and in the catalysis of macromolecular biological enzymes in water-in-oil and oil-in-oil environments.Additionally,the existing problems and future development directions of droplets in catalysis are highlighted to promote the development of catalytic reactions in droplet media and provide guidance for the high-throughput screening of catalysts and the directed evolution of biological enzymes.
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.
文摘As a follow-up to our previous study on the transesterification of Nigerian Jatropha curcas oil into Biodiesel using homogenous catalysis, kinetic study of the reaction is hereby presented. The kinetic study revealed that the rate of formation of biodiesel can be increased by increasing reaction temperature and oil to alcohol molar ratio. The optimum reaction condition was established to be 60°C (reaction temperature) and 1:6 (oil to alcohol ratio). Accordingly, the highest biodiesel yield obtained from homogeneously catalyzed transesterification of Nigerian Jatropha curcas (JC) oil into Biodiesel was 86.61% w/w at 60°C with oil to alcohol ratio of 1:6. Furthermore, kinetic study also revealed that conversion of triglyceride to diglyceride was the rate determining step (RDS) of the overall reaction because activation energy of its backward reaction is lower than that of the forward reaction, indicating unstable nature and higher potential energy of the diglyceride in comparison to the triglyceride.
基金supported by the National Science Foundation of China(nos.22071105 and 22031008)the Qinglan Project of Jiangsu Education Department.
文摘Although the combination of electrochemistry and homogeneous catalysis has proven to be a powerful strategy for achieving a diverse array of novel transformations,some challenges such as controlling the diffusion of catalyst-related species and the instability of catalysts at electrodes remain to be overcome.Herein,we review recent advances in electrochemical homogeneous catalysis,focusing on electrochemical noble-transition-metal catalysis,photoelectrochemical catalysis,and electrochemical enantioselective catalysis.The topics discussed include:(1)how the noblemetal catalystworks in the presence of cathodic hydrogen evolution,(2)how the photocatalyst gets enhanced redox property,and(3)how the enantioselectivity is regulated in a catalytic electrochemical reaction.
基金the National Key R&D Program of China(grant no.2021YFA1500200)the National Natural Science Foundation of China(grant nos.92256303 and 92056108)for financial support.
文摘Asymmetric hydrogenation of all-carbon aromatics is still a long-standing challenge in the area of asymmetric catalysis.To date,asymmetric(transfer)hydrogenation of naphthols and phenols remains unexplored.Here,we describe a new strategy for such asymmetric transformation via a bimetallic cooperative heterogeneous and homogeneous catalysis.By using HCOONa as the hydrogen source,various naphthols and phenols were partially hydrogenated in HFIP catalyzed by commercial Pd/C catalyst to give ketone intermediates.Further adding the second chiral Ru-tethered-TsDPEN catalyst and MeOH realized the asymmetric reduction of the resulting ketones in a one-pot manner,furnishing chiral alcohols with good to excellent enantioselectivity(up to 99%ee).The use of HFIP is crucial for suppressing ketone over-reduction via heterogeneous catalysis.More importantly,tandem asymmetric transfer hydrogenation of naphthols was also achieved by tuning the volume ratio of mixed HFIP/MeOH solvent,affording chiral 1,2,3,4-tetrahyronaphthols with excellent enantioselectivity but relatively low yield and limited substrate scope.
基金supported by the National Natural Science Foundation of China (20772114)the Innovation Fund for Outstanding Scholar of Henan Province (0621001100)
文摘Cyclopalladated ferrocenylimines as a novel kind of highly efficient palladium catalyst precursors, which are air-stable and easy to handle, have been successfully applied in a wide variety of catalytic reactions ranging from classical reactions, such as Heck, Suzuki, Sonogashira and Buchwald-Hartwig couplings, to cyanation, addition reactions of arylboronic acids, and coupling reactions involving terminal alkynes. The preliminary achievements regarding their applications to homogeneous catalysis are concisely described herein.
基金supported by the National Science Foundation,Division of Chemistry(NSF CHE 1800525).
文摘Over the past two decades,homogeneous gold catalysis has experienced exponential development and contributed a plethora of highly valuable synthetic methods to the synthetic toolbox.Metal–ligand cooperative catalysis is a versatile strategy for achieving highly efficient and/or novel catalysis but has seldom been explored in gold chemistry.This minireview summarizes the progress we have made in developing remotely functionalized biaryl-2-ylphosphine ligands and employing them in cooperative gold catalysis that achieves excellent catalytic efficiency or realizes previously unknown reactivities.This approach also provides new venues for implementing asymmetric gold catalysis.
文摘1 Results Significant progress has been made in recent years in developing efficient, atom economical catalytic reactions of potential applicability to the pharmaceutical, petrochemical, and commodity chemical business sectors. In some cases, homogeneous catalytic processes offer advantages, but in others the use of heterogenized homogeneous catalysis provides a competitive advantage concerning recyclability and catalyst recovery. This presentation will consider new approaches to cyclization reactions a...
基金supported by the National Natural Science Foundation of China(T2322013,22172077)the Natural Science Foundation of Jiangsu Province of China(BK 20211573)+3 种基金the Fundamental Research Funds for the Central Universities(30921011216)C.L was supported by China Scholarship Council(CSC)(202206840088)supported by the Ministry of Science and ICT through the National Research Foundation of Korea(2022H1D3A3A01077254,2021M3H4A1A03049662)the support from Yonsei-KIST Convergence Research Program and the Yonsei Fellow Program,funded by Lee Youn Jae.
文摘Photoelectrochemical(PEC)organic transformation at the anode coupled with cathodic H_(2) generation is a potentially rewarding strategy for efficient solar energy utilization.Nevertheless,achieving the full conversion of organic substrates with exceptional product selectivity remains a formidable hurdle in the context of heterogeneous catalysis at the solid/liquid interface.Here,we put forward a quasi-homogeneous catalysis concept by using the reactive oxygen species(ROS),such as·OH,H_(2)O_(2) and SO_(4)^(2-),as a charge transfer mediator instead of direct heterogeneous catalysis at the solid/liquid interface.In the context of glycerol oxidation,all ROS exhibited a preference forfirst-order reaction kinetics.These ROS,however,showcased distinct oxidation mechanisms,offering a range of advantages such as100%conversion ratios and theflexibility to tune the resulting products.Glycerol oxidative formic acid with Faradaic efficiency(FE)of 81.2%was realized by the H_(2)O_(2) and·OH,while SO_(4)^(2-)was preferably for glycerol conversion to C3 products like glyceraldehyde and dihydroxyacetone with a total FE of about 80%.Strikingly,the oxidative coupling of methane to ethanol was successfully achieved in our quasi-homogeneous system,yielding a remarkable production rate of 12.27 lmol h^(-1) and an impressive selectivity of 92.7%.This study is anticipated to pave the way for novel approaches in steering solar-driven organic conversions by manipulating ROS to attain desired products and conversion ratios.
基金support from the National Key Research and Development Program of China(grant nos.2022YFA1502900,2022YFA0911900,2021YFA1500800,and 2022YFB3803600)the National Natural Science Foundation of China(grant nos.20231001,22201288,21933007,22193013,and 22088102)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Science(grant no.XDB17000000)the New Cornerstone Science Foundation.
文摘Photocatalytic water oxidation reaction by transition metal complexes remains a challenge because of their poor stability under irradiation,especially for earth-abundant metal catalysts.In this regard,ironbased water oxidation catalysts are prone to hydrolysis and/or dissociate the ligands to form nanoparticles under a real catalytic condition.Herein,we describe a unique hexa-coordinated catalyst 1[Fe^(II)(Py_(3)tacn)Cl_(2)]and its reference 2[Fe^(II)(PhPy_(2)tacn)Cl_(2)]with a dangling pyridyl ligand and a phenyl group,respectively.We anticipated that the dynamically open and close coordination behaviors of the pyridyl ligand enabled balance of the reactivity and stability of catalyst 1.To our delight,the“open form”of catalyst 1 provided a free coordination site,and the“close form”guaranteed its molecular integrity,resulting in a water oxidation reaction with high efficiency and robustness.The turnover number and turnover frequency values of 2332 and 60 s^(−1)are the highest known to date among iron-based homogeneous water oxidation systems under visible light irradiation.