Constructing catalysts featuring an ordered structure,stable performance,and uniformly dispersed catalytic sites is vital for the epoxidation of small-molecular olefins.Here,we design catalysts by tracing the oxidatio...Constructing catalysts featuring an ordered structure,stable performance,and uniformly dispersed catalytic sites is vital for the epoxidation of small-molecular olefins.Here,we design catalysts by tracing the oxidationprocess origin and synthesize a series of highly dispersed metal porphyrin-based covalent organic frameworks(COFs)materials.The aim is to efficiently oxidize the C-H bonds of cumene by air to in-situ generate organic peroxides at a safe concentration,and integrate the multi-step oxidation method of cumene in industry into a one-step method for olefins’epoxidation.The carbonyl-ruthenium COF(Ru-COF-1)exhibits excellent performance,with 98% epoxide selectivity,1221.77 h^(-1) productivity,and over 95% selectivity after 9 cycles for 1-hexene.Analysis of structure-properties-catalytic relationships of Ru-COF-1 shows that,compared with Ru-porphyrins and metal-free COFs,the enhanced reaction performance mainly results from Ru metal introduction,which promotes benzylic proton transfer in cumene.Besides,Ru-COF-1’s porous,ordered structure aids oxygen enrichment,forming active peroxy radicals with the cumene carboncentered radicals formed on the catalyst surface.Ru-H sites then accelerate active oxygen transfer from peroxy radicals,enabling olefin tandem epoxidation.Density functional theory(DFT)calculations verify the reaction mechanism,and this work offers a reference for the design of catalysts for the green,safe,and efficient oxidation of olefins.展开更多
近日,荷兰Blue Circle Olefins公司、英国废品回收公司(Renewi)与荷兰莫尔迪克运输公司等联合启动一项使用废弃物制可再生甲醇、可再生甲醇制烯烃(乙烯/丙烯)项目的可行性研究。该项目获得荷兰企业署TSE资助,旨在利用不适合机械回收的...近日,荷兰Blue Circle Olefins公司、英国废品回收公司(Renewi)与荷兰莫尔迪克运输公司等联合启动一项使用废弃物制可再生甲醇、可再生甲醇制烯烃(乙烯/丙烯)项目的可行性研究。该项目获得荷兰企业署TSE资助,旨在利用不适合机械回收的废塑料等物质。展开更多
Double bonds of internal olefins can be efficiently migrated to the terminal carbons and regioselectively hydroesterified with formates in the presence of Pd(OAc)_(2) and 1,2-DTBPMB under mild reaction conditions,prov...Double bonds of internal olefins can be efficiently migrated to the terminal carbons and regioselectively hydroesterified with formates in the presence of Pd(OAc)_(2) and 1,2-DTBPMB under mild reaction conditions,providing a wide variety of corresponding linear carboxylic esters bearing various functional groups in good yields and>20:1 linear/branch ratios.The reaction is optionally simple and does not need to use CO gas and acid co-catalysts.展开更多
Modifying the electronic density of states and the synergistic effect of the active centers by introducing a second metal present an efficient strategy to tune physi/chemi-sorption,probably lead to improving catalytic...Modifying the electronic density of states and the synergistic effect of the active centers by introducing a second metal present an efficient strategy to tune physi/chemi-sorption,probably lead to improving catalytic performances.Herein,bimetallic Ni_(3)Mo/Al_(2)O_(3)catalyst was demonstrated and exhibited over 5 times more active than Pt/Al_(2)O_(3)toward the ethane dehydrogenation(EDH)as well as 2-10 times activity enhancement compared with their monometallic Ni and Mo counterparts and other Ni-based bimetallic nanoparticles.Kinetic studies revealed that the activation energy over Ni_(3)Mo/Al_(2)O_(3)(111 kJ mol^(-1))was much lower than that of Ni(157 kJ mol^(-1))and Mo(171 kJ·mol^(-1)).DFT calculations showed ethane was adsorbed on the Ni or Mo surface in a more parallel configuration,whereas over Ni_(3)Mo it adopted an inclined configuration.This change promoted ethane adsorption and pre-activation of the C-H bond,thereby benefiting the ethane dehydrogenation process on the Ni_(3)Mo surface.展开更多
The fabrication of monolithic ZSM-5 catalysts via extrusion is pivotal for industrial catalytic processes;nevertheless,the addition of adhesives might affect their catalytic performance.Herein,the rice husk-derived bi...The fabrication of monolithic ZSM-5 catalysts via extrusion is pivotal for industrial catalytic processes;nevertheless,the addition of adhesives might affect their catalytic performance.Herein,the rice husk-derived bio-SiO_(2),serving as a silicon source and natural adhesive,was introduced in the synthesis and extrusion of ZSM-5 catalysts denoted as BioZSM-5,thereby enhancing their industrial viability and catalytic performance.The f-n-BioZSM-5(obtained by extrusion of n-BioZSM-5)showcased enhanced butene and pentene selectivity,exhibiting robust stability,achieving an impressive 84.8%olefin selectivity(over 10 cycles).The biomass template significantly improved porosity,acidity,and anti-coking properties.Moreover,the f-n-BioZSM-5 exhibited a compressive strength 4.3 times superior to that of f-n-ZSM-5 without using bio-template,achieving better abrasion resistance and enhanced mechanical properties even using 1/3 of the adhesive dosage.These results will provide valuable guidance for developing shaped zeolite catalysts for industrial catalytic pyrolysis applications,especially for the production of olefin from fatty acids.展开更多
The concept of liquid-solid hybrid catalyst that featuring a truly homogeneous liquid microenvironment together with insoluble solid characteristics has been established recently by our group,which enables us to conve...The concept of liquid-solid hybrid catalyst that featuring a truly homogeneous liquid microenvironment together with insoluble solid characteristics has been established recently by our group,which enables us to conveniently bridge the gap between homo-and heterogeneous catalysis.In this study,we extend this general concept to the confinement of molecular rhodium phosphine complexes,including Rh-TPPTS,Rh-TPPMS and Rh-SXP,for olefin hydroformylation reactions.A series of hybrid catalyst materials consisting a modulated liquid interior([BMIM]NTf_(2),[BMIM]PF_(6),[BMIM]BF_(4) or H_(2)O)and a permeable silica crust were fabricated through our developed Pickering emulsion-based method,showing 9.4–24.2-fold activity enhancement and significantly improved aldehyde selectivity(from 72.2%,61.8%to 86.6%)compared to their biphasic counterparts or traditional supported liquid phase system in the hydroformylation of 1-dodecene.Interestingly,the catalytic efficiency was demonstrated to be tunable by rationally engineering the thickness of porous crust and dimensions of the liquid pool.The thus-attained hybrid catalyst could also successfully catalyze the hydroformylation of a variety of olefin substrates and be recycled without a significant loss of activity for at least seven times.展开更多
Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,a...Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,and process optimization have significantly improved the efficiency,selectivity,and sustainability of these processes.This Account introduces the relevant research activities in the Research Center for Catalysis in Syngas Conversion and Fine Chemicals(DNL0805)of Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences.The reactions of interests include FTS,heterogeneous hydroformylation of olefins,alcohol dehydration and oxidation,andα-olefin polymerization,with the emphasis on developing innovative catalysts and processes to address the challenges of traditional processes.Exemplified by the discovery of robust Co-Co_(2)C/AC for FTS and Rh_(1)/POPs-PPh_(3) for heterogeneous hydroformylation of olefins,it demonstrates how lab-scale fundamental understandings on the active sites of catalysts leads to pilot-plant scale-up and finally commercial technologies.Perspectives on the challenges and directions for future developments in these exciting fields are provided.展开更多
Separation of ternary C_(4) olefins(n-butene,iso-butene and 1,3-butadiene)is very challenging but crucial in the petrol-chemical industry due to their similar molecular sizes and properties.Herein,to optimize the sepa...Separation of ternary C_(4) olefins(n-butene,iso-butene and 1,3-butadiene)is very challenging but crucial in the petrol-chemical industry due to their similar molecular sizes and properties.Herein,to optimize the separation efficiency for separation of C_(4) olefins,a new Hofmann-type MOF,[Ni(piz)Ni(CN)_(4)](piz=piperazine)-isostructural to the typical one[Ni(pyz)Ni(CN)_(4)](pyz=pyrazine),has been synthesized by a facile method from aqueous solution.The pore size reduction of[Ni(piz)Ni(CN)_(4)](3.62A,in contrast to 3.85A in[Ni(pyz)Ni(CN)_(4)])results in negligible iso-butene(i-C_(4)H_(8))uptake(from 2.92 to 0.04 mmol g^(-1))whereas retaining significant uptake for 1,3-butadiene(1,3-C_(4)H_(6),1.96 mmol g^(-1))and n-butene(n-C_(4)H_(8),1.47 mmol g^(-1)),showing much higher uptake ratios of 1,3-C_(4)H_(6)/i-C_(4)H_(8)(47)and n-C_(4)H_(8)/i-C_(4)H_(8)(35)that outperform most of the benchmark porous materials for separating C_(4) olefins.Breakthrough experiments demonstrate successful separation of high-purity(99.9999%)i-C_(4)H_(8) and 1,3-C_(4)H_(6) from equimolar 1,3-C_(4)H_(6)/i-C_(4)H_(8),n-C_(4)H_(8)/i-C_(4)H_(8) and 1,3-C_(4)H_(6)/n-C_(4)H_(8)/i-C_(4)H_(8) mixtures.展开更多
The development of human industry inevitably leads to excessive carbon dioxide(CO_(2))emissions.It can cause critical ecological consequences,primarily global warming and ocean acidification.In this regard,close atten...The development of human industry inevitably leads to excessive carbon dioxide(CO_(2))emissions.It can cause critical ecological consequences,primarily global warming and ocean acidification.In this regard,close attention is paid to the carbon capture,utilization,and storage concept.The key component of this concept is the catalytic conversion of CO_(2)into valuable chemical compounds and fuels.Light olefins are one of the most industrially important chemicals,and their sustainable production via CO_(2)hydrogenation could be a prospective way to reach carbon neutrality.Fe-based materials are widely recognized as effective thermocatalysts and photothermal catalysts for that process thanks to their low cost,high activity,and good stability.This review critically examines the most recent progress in the development and optimization of Fe-based catalysts for CO_(2)hydrogenation into light olefins.Particular attention is paid to understanding the roles of catalyst composition,structural properties,and promoters in enhancing catalytic activity,selectivity,and stability.展开更多
The design of low-cost and high-performance cyclic olefin copolymers remains challenging.Ethylene copolymers with dicyclopentadiene(DCPD)were prepared using Ph_(2)C(Cp)(Flu)ZrCl_(2)(Cat.1),rac-Et(Ind)_(2)ZrCl_(2)(Cat....The design of low-cost and high-performance cyclic olefin copolymers remains challenging.Ethylene copolymers with dicyclopentadiene(DCPD)were prepared using Ph_(2)C(Cp)(Flu)ZrCl_(2)(Cat.1),rac-Et(Ind)_(2)ZrCl_(2)(Cat.2),Me_(2)C(Cp)(Flu)ZrCl_(2)(Cat.3)andMe_(2)Si(Ind)_(2)ZrCl_(2)(Cat.4)combined with[Ph_(3)C][B(C_(6)F_(5))_(4)]/iBu_(3)Al.Ni(acac)_(2)/iBu_(3)Al was then used to catalyze the hydrogenation of the intracyclic double bonds of ethylene/DCPD copolymers.The results showed that compared to C_(2) symmetric catalysts(Cat.2 and Cat.4),Cs symmetric catalysts(Cat.1 and Cat.3)facilitated the incorporation of copolymers with higher DCPD.1H-and ^(13)C-NMR spectra indicated that ethylene/DCPD copolymerization occurred via enhancement of the norbornene ring.Additionally,measurement of the reactivity ratios provided further confirmation that the copolymers had random sequence distributions.All these samples demonstrated transmittance values above 90%in the visible wavelength range from 400 nm to 800 nm.By changing the fraction of monomers,the glass transition temperature,refractive index,Young's modulus,and tensile strength of the copolymer increased as the incorporation of DCPD increased,whereas the Abbe number and elongation at break decreased.Compared with ethylene/norbornene and ethylene/tetracyclicdodecene copolymers,ethylene/DCPD copolymers,with excellent optical and mechanical properties,are promising materials.展开更多
The design and synthesis of a novel π-conjugated fiuorescent framework by external ligand-assisted C-H olefination of heterocycles with excellent regioselectivity and broad substrate scope are reported herein.These n...The design and synthesis of a novel π-conjugated fiuorescent framework by external ligand-assisted C-H olefination of heterocycles with excellent regioselectivity and broad substrate scope are reported herein.These novel fiuorescent materials could present full-color-tunable emissions with large Stokes shifts. Furthermore, the protocol provides an opportunity to rapidly screen novel organic single-molecule whitelight materials with high fiuorescence quantum yields. The robust organic and low-cost white lightemitting diodes could rapidly be fabricated using the white-light-emitting material. Experimental data and theoretical calculations indicate that in the white-light dual emission the relatively short wavelength from high-lying singlet state emission and the relatively long wavelength from low-lying singlet state emission. The anti-Kasha dual-emission systems will provide a foundation for the development and application of organic single-molecule white light materials, effectively promoting the development and innovation of luminescent materials. In addition, this method demonstrated its potential application in the synthesis of new near-infrared(NIR) fiuorescence materials with large Stokes shifts based on the olefination of heterocycles.展开更多
With the rapid development of economy,the consumption of fossil fuels and excessive emissions of carbon dioxide(CO_(2))have led to many environmental issues.The thermocatalytic conversion of CO_(2) to high value‐adde...With the rapid development of economy,the consumption of fossil fuels and excessive emissions of carbon dioxide(CO_(2))have led to many environmental issues.The thermocatalytic conversion of CO_(2) to high value‐added chemicals is an effective strategy to meet the need of carbon neutralization.Among them,CO_(2) hydrogenation to light olefins has been well researched so that the selectivity of desired products can exceed the Anderson–Schulz–Flory(ASF)distribution to acquire an extremely high yield.However,although huge progress has been made in CO_(2) hydrogenation to produce long‐chainα‐olefins based on Fe catalysts as well,designing efficient catalysts with promoted C‐O dissociation and C‐C coupling remains challenging.In addition,ASF distribution restrains the selectivity of desired long‐chain products,whereas the approaches to breaking it still face issues.In this review,we focus on the design of Fe‐based catalysts for the synthesis of long‐chainα‐olefins through CO_(2) hydrogenation.We have summarized and analyzed the reaction mechanism,design of catalysts,structure–activity relationship,interaction between Fe and promoters,and strategies to break the ASF distribution.At the same time,the issues faced by CO_(2) hydrogenation to long‐chainα‐olefins are proposed and the possible future solutions are prospected.This review aims to provide a recent development on the design of Fe‐based catalysts for CO_(2) hydrogenation to long‐chainα‐olefins while considering the ASF distribution.展开更多
Direct conversion of syngas to light olefins(STO)on bifunctional catalysts has garnered significant attention,yet a comprehensive understanding of the reaction pathway and reaction kinetics remains elusive.Herein,we t...Direct conversion of syngas to light olefins(STO)on bifunctional catalysts has garnered significant attention,yet a comprehensive understanding of the reaction pathway and reaction kinetics remains elusive.Herein,we theoretically addressed the kinetics of the direct STO reaction on typical ZnAl_(2)O_(4)/zeolite catalysts by establishing a complete reaction network,consisting of methanol synthesis and conversion,water gas shift(WGS)reaction,olefin hydrogenation,and other relevant steps.The WGS reaction occurs very readily on ZnAl_(2)O_(4) surface whereas which is less active towards alkane formation via olefin hydrogenation,and the latter can be attributed to the characteristics of the H_(2) heterolytic activation and the weak polarity of olefins.The driving effect of zeolite component towards CO conversion was demonstrated by microkinetic simulations,which is sensitive to reaction conditions like space velocity and reaction temperature.Under a fixed ratio of active sites between oxide and zeolite components,the concept of the“impossible trinity”of high CO conversion,high olefin selectivity,and high space velocity can thus be manifested.This work thus provides a comprehensive kinetic picture on the direct STO conversion,offering valuable insights for the design of each component of bifunctional catalysts and the optimization of reaction conditions.展开更多
Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we...Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we find that the addition of moderate amounts of Ti forms a strong interaction with Fe compositions,modulating the Fe_(3)O_(4)and Fe_(5)C_(2)contents.Enhanced interaction leads to an increased Fe_(5)C_(2)/Fe_(3)O_(4)ratio,which in turn enhances the adsorption of reactants and intermediates,promoting CO hydrogenation to unsaturated alkyl groups and facilitating C–C coupling.Furthermore,the strong Fe-Ti interaction induces the preferential growth of Fe_(5)C_(2)into prismatic structures that expose the(020),(–112),and(311)facets,forming compact active interfacial sites with Fe_(3)O_(4)nanoparticles.These facet and interfacial effects significantly promote the synergistic coupling of the reverse water gas shift and Fischer-Tropsch reactions.The optimized 3K/FeTi catalyst with the highest Fe_(5)C_(2)/Fe_(3)O_(4)ratio of 3.6 achieves a 52.2%CO_(2)conversion rate,with 44.5%selectivity for C2–4=and 9.5%for CO,and the highest space-time yield of 412.0 mg gcat^(–1)h^(–1)for C_(2–4)=.展开更多
Fe‐based catalysts for the production of light olefins via the Fischer‐Tropsch synthesis were modi‐fied by adding a Zn promoter using both microwave‐hydrothermal and impregnation methods. The physicochemical prope...Fe‐based catalysts for the production of light olefins via the Fischer‐Tropsch synthesis were modi‐fied by adding a Zn promoter using both microwave‐hydrothermal and impregnation methods. The physicochemical properties of the resulting catalysts were determined by scanning electron mi‐croscopy, the Brunauer‐Emmett‐Teller method, X‐ray diffraction, H2 temperature‐programed re‐duction and X‐ray photoelectron spectroscopy. The results demonstrate that the addition of a Zn promoter improves both the light olefin selectivity over the catalyst and the catalyst stability. The catalysts prepared via the impregnation method, which contain greater quantities of surface ZnO, exhibit severe carbon deposition following activity trials. In contrast, those materials synthesized using the microwave‐hydrothermal approach show improved dispersion of Zn and Fe phases and decreased carbon deposition, and so exhibit better CO conversion and stability.展开更多
The ZSM-5 zeolite with an unusual snowflake-shaped morphology was hydrothermally synthesized for the first time,and compared with common ellipsoidal and boat-like shaped samples.These samples were characterized by N2 ...The ZSM-5 zeolite with an unusual snowflake-shaped morphology was hydrothermally synthesized for the first time,and compared with common ellipsoidal and boat-like shaped samples.These samples were characterized by N2 adsorption-desorption,X-ray fluorescence spectroscopy,scanning electron microscopy,X-ray diffraction,magic angle spinning nuclear magnetic resonance,temperature-programmed desorption of ammonia,and infrared spectroscopy of pyridine adsorption.The results suggest that the BET surface area and SiO2/Al2O3 ratio of these samples are similar,while the snowflake-shaped ZSM-5 zeolite possesses more of the（101） face,and distortion,dislocation,and asymmetry in the framework,resulting in a larger number of acid sites than the conventional samples.Catalysts for the methanol to olefin（MTO） reaction were prepared by loading Ca on the samples.The snowflake-shaped Ca/ZSM-5 zeolite exhibited excellent selectivity for total light olefin（72%） and propene（39%） in MTO.The catalytic performance influenced by the morphology can be mainly attributed to the snowflake-shaped ZSM-5 zeolite possessing distortion,dislocation,and asymmetry in the framework,and lower diffusion limitation than the conventional samples.展开更多
The catalytic performance of solid catalysts depends on the properties of the catalytically active sites and their accessibility to reactants, which are significantly affected by the microstructure（morphology, shape,...The catalytic performance of solid catalysts depends on the properties of the catalytically active sites and their accessibility to reactants, which are significantly affected by the microstructure（morphology, shape, size, texture, and surface structure） and surface chemistry（elemental components and chemical states）. The development of facile and efficient methods for tailoring the microstructure and surface chemistry is a hot topic in catalysis. This contribution reviews the state of the art in modulating the microstructure and surface chemistry of carbocatalysts by both bottom‐up and top‐down strategies and their use in the oxidative dehydrogenation（ODH） and direct dehydrogenation（DDH） of hydrocarbons including light alkanes and ethylbenzene to their corresponding olefins, important building blocks and chemicals like oxygenates. A concept of microstructure and surface chemistry tuning of the carbocatalyst for optimized catalytic performance and also for the fundamental understanding of the structure‐performance relationship is discussed. We also highlight the importance and challenges in modulating the microstructure and surface chemistry of carbocatalysts in ODH and DDH reactions of hydrocarbons for the highly‐efficient, energy‐saving,and clean production of their corresponding olefins.展开更多
The density functional theory on the level of B3LYP/6-31G was empolyed to study the chain growth mechanism in polymerization process of α-linear olefin in TiCl3/AlEt2Cl catalytic system to synthesize drag reduction a...The density functional theory on the level of B3LYP/6-31G was empolyed to study the chain growth mechanism in polymerization process of α-linear olefin in TiCl3/AlEt2Cl catalytic system to synthesize drag reduction agent. Full parameter optimization without symmetry restrictions for reactants, products, the possible transition states, and intermediates was calculated. Vibration frequency was analyzed for all of stagnation points on the potential energy surface at the same theoretical level. The internal reaction coordinate was calculated from the transition states to reactants and products respectively. The results showed as flloes： （i） Coordination compounds were formed on the optimum configuration of TiCl3/AlEt2Cl.（ii） The transition states were formed. The energy di？erence between transition states and the coordination compounds was 40.687 kJ/mol. （iii） Double bond opened and Ti-C（4） bond fractured, and the polymerization was completed. The calculation results also showed that the chain growth mechanism did not essentially change with the increase of carbon atom number of α-linear olefin. From the relationship between polymerization activation energy and carbon atom number of the α-linear olefin, it can be seen that the α-linear olefin monomers with 6-10 carbon atoms had low activation energy and wide range. It was optimum to synthesize drag reduction agent by polymerization.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22508360)Zhejiang Provincial Natural Science Foundation of China(No.QN26B060028)+1 种基金the National Key Research and Development Program Nanotechnology Specific Project(No.2020YFA0210900)Innovative Team Project of Guang-dong Ordinary University(No.2019KCXTD002).
文摘Constructing catalysts featuring an ordered structure,stable performance,and uniformly dispersed catalytic sites is vital for the epoxidation of small-molecular olefins.Here,we design catalysts by tracing the oxidationprocess origin and synthesize a series of highly dispersed metal porphyrin-based covalent organic frameworks(COFs)materials.The aim is to efficiently oxidize the C-H bonds of cumene by air to in-situ generate organic peroxides at a safe concentration,and integrate the multi-step oxidation method of cumene in industry into a one-step method for olefins’epoxidation.The carbonyl-ruthenium COF(Ru-COF-1)exhibits excellent performance,with 98% epoxide selectivity,1221.77 h^(-1) productivity,and over 95% selectivity after 9 cycles for 1-hexene.Analysis of structure-properties-catalytic relationships of Ru-COF-1 shows that,compared with Ru-porphyrins and metal-free COFs,the enhanced reaction performance mainly results from Ru metal introduction,which promotes benzylic proton transfer in cumene.Besides,Ru-COF-1’s porous,ordered structure aids oxygen enrichment,forming active peroxy radicals with the cumene carboncentered radicals formed on the catalyst surface.Ru-H sites then accelerate active oxygen transfer from peroxy radicals,enabling olefin tandem epoxidation.Density functional theory(DFT)calculations verify the reaction mechanism,and this work offers a reference for the design of catalysts for the green,safe,and efficient oxidation of olefins.
基金financial support from the National Natural Science Foundation of China(Nos.22271024,21632005)Changzhou University.
文摘Double bonds of internal olefins can be efficiently migrated to the terminal carbons and regioselectively hydroesterified with formates in the presence of Pd(OAc)_(2) and 1,2-DTBPMB under mild reaction conditions,providing a wide variety of corresponding linear carboxylic esters bearing various functional groups in good yields and>20:1 linear/branch ratios.The reaction is optionally simple and does not need to use CO gas and acid co-catalysts.
文摘Modifying the electronic density of states and the synergistic effect of the active centers by introducing a second metal present an efficient strategy to tune physi/chemi-sorption,probably lead to improving catalytic performances.Herein,bimetallic Ni_(3)Mo/Al_(2)O_(3)catalyst was demonstrated and exhibited over 5 times more active than Pt/Al_(2)O_(3)toward the ethane dehydrogenation(EDH)as well as 2-10 times activity enhancement compared with their monometallic Ni and Mo counterparts and other Ni-based bimetallic nanoparticles.Kinetic studies revealed that the activation energy over Ni_(3)Mo/Al_(2)O_(3)(111 kJ mol^(-1))was much lower than that of Ni(157 kJ mol^(-1))and Mo(171 kJ·mol^(-1)).DFT calculations showed ethane was adsorbed on the Ni or Mo surface in a more parallel configuration,whereas over Ni_(3)Mo it adopted an inclined configuration.This change promoted ethane adsorption and pre-activation of the C-H bond,thereby benefiting the ethane dehydrogenation process on the Ni_(3)Mo surface.
基金financially supported by the National Natural Science Foundation of China(U21A20324,22278167,22350410389 and 22322806)the Fujian Provincial Natural Science Foundation of China(2024J01100)。
文摘The fabrication of monolithic ZSM-5 catalysts via extrusion is pivotal for industrial catalytic processes;nevertheless,the addition of adhesives might affect their catalytic performance.Herein,the rice husk-derived bio-SiO_(2),serving as a silicon source and natural adhesive,was introduced in the synthesis and extrusion of ZSM-5 catalysts denoted as BioZSM-5,thereby enhancing their industrial viability and catalytic performance.The f-n-BioZSM-5(obtained by extrusion of n-BioZSM-5)showcased enhanced butene and pentene selectivity,exhibiting robust stability,achieving an impressive 84.8%olefin selectivity(over 10 cycles).The biomass template significantly improved porosity,acidity,and anti-coking properties.Moreover,the f-n-BioZSM-5 exhibited a compressive strength 4.3 times superior to that of f-n-ZSM-5 without using bio-template,achieving better abrasion resistance and enhanced mechanical properties even using 1/3 of the adhesive dosage.These results will provide valuable guidance for developing shaped zeolite catalysts for industrial catalytic pyrolysis applications,especially for the production of olefin from fatty acids.
文摘The concept of liquid-solid hybrid catalyst that featuring a truly homogeneous liquid microenvironment together with insoluble solid characteristics has been established recently by our group,which enables us to conveniently bridge the gap between homo-and heterogeneous catalysis.In this study,we extend this general concept to the confinement of molecular rhodium phosphine complexes,including Rh-TPPTS,Rh-TPPMS and Rh-SXP,for olefin hydroformylation reactions.A series of hybrid catalyst materials consisting a modulated liquid interior([BMIM]NTf_(2),[BMIM]PF_(6),[BMIM]BF_(4) or H_(2)O)and a permeable silica crust were fabricated through our developed Pickering emulsion-based method,showing 9.4–24.2-fold activity enhancement and significantly improved aldehyde selectivity(from 72.2%,61.8%to 86.6%)compared to their biphasic counterparts or traditional supported liquid phase system in the hydroformylation of 1-dodecene.Interestingly,the catalytic efficiency was demonstrated to be tunable by rationally engineering the thickness of porous crust and dimensions of the liquid pool.The thus-attained hybrid catalyst could also successfully catalyze the hydroformylation of a variety of olefin substrates and be recycled without a significant loss of activity for at least seven times.
文摘Fischer-Tropsch synthesis(FTS)and hydroformylation are pivotal chemical processes for converting syngas and olefins into valuable hydrocarbons and chemicals.Recent advancements in catalyst design,reaction mechanisms,and process optimization have significantly improved the efficiency,selectivity,and sustainability of these processes.This Account introduces the relevant research activities in the Research Center for Catalysis in Syngas Conversion and Fine Chemicals(DNL0805)of Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences.The reactions of interests include FTS,heterogeneous hydroformylation of olefins,alcohol dehydration and oxidation,andα-olefin polymerization,with the emphasis on developing innovative catalysts and processes to address the challenges of traditional processes.Exemplified by the discovery of robust Co-Co_(2)C/AC for FTS and Rh_(1)/POPs-PPh_(3) for heterogeneous hydroformylation of olefins,it demonstrates how lab-scale fundamental understandings on the active sites of catalysts leads to pilot-plant scale-up and finally commercial technologies.Perspectives on the challenges and directions for future developments in these exciting fields are provided.
基金supported by National Natural Science Foundation of China(22090061,22375221)Fundamental Research Program of Shanxi Province(No.202203021223004)+1 种基金Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2017ZT07C069)Hundred Talents Program of Sun Yat-Sen University.
文摘Separation of ternary C_(4) olefins(n-butene,iso-butene and 1,3-butadiene)is very challenging but crucial in the petrol-chemical industry due to their similar molecular sizes and properties.Herein,to optimize the separation efficiency for separation of C_(4) olefins,a new Hofmann-type MOF,[Ni(piz)Ni(CN)_(4)](piz=piperazine)-isostructural to the typical one[Ni(pyz)Ni(CN)_(4)](pyz=pyrazine),has been synthesized by a facile method from aqueous solution.The pore size reduction of[Ni(piz)Ni(CN)_(4)](3.62A,in contrast to 3.85A in[Ni(pyz)Ni(CN)_(4)])results in negligible iso-butene(i-C_(4)H_(8))uptake(from 2.92 to 0.04 mmol g^(-1))whereas retaining significant uptake for 1,3-butadiene(1,3-C_(4)H_(6),1.96 mmol g^(-1))and n-butene(n-C_(4)H_(8),1.47 mmol g^(-1)),showing much higher uptake ratios of 1,3-C_(4)H_(6)/i-C_(4)H_(8)(47)and n-C_(4)H_(8)/i-C_(4)H_(8)(35)that outperform most of the benchmark porous materials for separating C_(4) olefins.Breakthrough experiments demonstrate successful separation of high-purity(99.9999%)i-C_(4)H_(8) and 1,3-C_(4)H_(6) from equimolar 1,3-C_(4)H_(6)/i-C_(4)H_(8),n-C_(4)H_(8)/i-C_(4)H_(8) and 1,3-C_(4)H_(6)/n-C_(4)H_(8)/i-C_(4)H_(8) mixtures.
基金supported by the Ministry of Higher Education,Science and Innovation,and the Slovenian Research Agency(ARIS)throughresearch grants J7-4638 and J2-4441.
文摘The development of human industry inevitably leads to excessive carbon dioxide(CO_(2))emissions.It can cause critical ecological consequences,primarily global warming and ocean acidification.In this regard,close attention is paid to the carbon capture,utilization,and storage concept.The key component of this concept is the catalytic conversion of CO_(2)into valuable chemical compounds and fuels.Light olefins are one of the most industrially important chemicals,and their sustainable production via CO_(2)hydrogenation could be a prospective way to reach carbon neutrality.Fe-based materials are widely recognized as effective thermocatalysts and photothermal catalysts for that process thanks to their low cost,high activity,and good stability.This review critically examines the most recent progress in the development and optimization of Fe-based catalysts for CO_(2)hydrogenation into light olefins.Particular attention is paid to understanding the roles of catalyst composition,structural properties,and promoters in enhancing catalytic activity,selectivity,and stability.
基金supported by the National Natural Science Foundation of China(Nos.52130307 and 5240031453).
文摘The design of low-cost and high-performance cyclic olefin copolymers remains challenging.Ethylene copolymers with dicyclopentadiene(DCPD)were prepared using Ph_(2)C(Cp)(Flu)ZrCl_(2)(Cat.1),rac-Et(Ind)_(2)ZrCl_(2)(Cat.2),Me_(2)C(Cp)(Flu)ZrCl_(2)(Cat.3)andMe_(2)Si(Ind)_(2)ZrCl_(2)(Cat.4)combined with[Ph_(3)C][B(C_(6)F_(5))_(4)]/iBu_(3)Al.Ni(acac)_(2)/iBu_(3)Al was then used to catalyze the hydrogenation of the intracyclic double bonds of ethylene/DCPD copolymers.The results showed that compared to C_(2) symmetric catalysts(Cat.2 and Cat.4),Cs symmetric catalysts(Cat.1 and Cat.3)facilitated the incorporation of copolymers with higher DCPD.1H-and ^(13)C-NMR spectra indicated that ethylene/DCPD copolymerization occurred via enhancement of the norbornene ring.Additionally,measurement of the reactivity ratios provided further confirmation that the copolymers had random sequence distributions.All these samples demonstrated transmittance values above 90%in the visible wavelength range from 400 nm to 800 nm.By changing the fraction of monomers,the glass transition temperature,refractive index,Young's modulus,and tensile strength of the copolymer increased as the incorporation of DCPD increased,whereas the Abbe number and elongation at break decreased.Compared with ethylene/norbornene and ethylene/tetracyclicdodecene copolymers,ethylene/DCPD copolymers,with excellent optical and mechanical properties,are promising materials.
基金the Fundamental Research Funds for the Central Universities (Nos. 2024CDJXY0022023CDJYGRH-YB17+4 种基金2022CDJXY-025)the Venture & Innovation Support Program for Chongqing Overseas Returnees (No. cx2022061)the Natural Science Foundation of Chongqing (No. CSTB2022NSCQ-MSX1123)the Chongqing Talents: Exceptional Young Talents Project (No. cstc2021ycjh-bgzxm0067)the Hongshen Young Scholars Program from Chongqing University (No. 0247001104426) for financial support。
文摘The design and synthesis of a novel π-conjugated fiuorescent framework by external ligand-assisted C-H olefination of heterocycles with excellent regioselectivity and broad substrate scope are reported herein.These novel fiuorescent materials could present full-color-tunable emissions with large Stokes shifts. Furthermore, the protocol provides an opportunity to rapidly screen novel organic single-molecule whitelight materials with high fiuorescence quantum yields. The robust organic and low-cost white lightemitting diodes could rapidly be fabricated using the white-light-emitting material. Experimental data and theoretical calculations indicate that in the white-light dual emission the relatively short wavelength from high-lying singlet state emission and the relatively long wavelength from low-lying singlet state emission. The anti-Kasha dual-emission systems will provide a foundation for the development and application of organic single-molecule white light materials, effectively promoting the development and innovation of luminescent materials. In addition, this method demonstrated its potential application in the synthesis of new near-infrared(NIR) fiuorescence materials with large Stokes shifts based on the olefination of heterocycles.
基金supported by the CNPC Innovation Found(2021DQ02‐0702).
文摘With the rapid development of economy,the consumption of fossil fuels and excessive emissions of carbon dioxide(CO_(2))have led to many environmental issues.The thermocatalytic conversion of CO_(2) to high value‐added chemicals is an effective strategy to meet the need of carbon neutralization.Among them,CO_(2) hydrogenation to light olefins has been well researched so that the selectivity of desired products can exceed the Anderson–Schulz–Flory(ASF)distribution to acquire an extremely high yield.However,although huge progress has been made in CO_(2) hydrogenation to produce long‐chainα‐olefins based on Fe catalysts as well,designing efficient catalysts with promoted C‐O dissociation and C‐C coupling remains challenging.In addition,ASF distribution restrains the selectivity of desired long‐chain products,whereas the approaches to breaking it still face issues.In this review,we focus on the design of Fe‐based catalysts for the synthesis of long‐chainα‐olefins through CO_(2) hydrogenation.We have summarized and analyzed the reaction mechanism,design of catalysts,structure–activity relationship,interaction between Fe and promoters,and strategies to break the ASF distribution.At the same time,the issues faced by CO_(2) hydrogenation to long‐chainα‐olefins are proposed and the possible future solutions are prospected.This review aims to provide a recent development on the design of Fe‐based catalysts for CO_(2) hydrogenation to long‐chainα‐olefins while considering the ASF distribution.
文摘Direct conversion of syngas to light olefins(STO)on bifunctional catalysts has garnered significant attention,yet a comprehensive understanding of the reaction pathway and reaction kinetics remains elusive.Herein,we theoretically addressed the kinetics of the direct STO reaction on typical ZnAl_(2)O_(4)/zeolite catalysts by establishing a complete reaction network,consisting of methanol synthesis and conversion,water gas shift(WGS)reaction,olefin hydrogenation,and other relevant steps.The WGS reaction occurs very readily on ZnAl_(2)O_(4) surface whereas which is less active towards alkane formation via olefin hydrogenation,and the latter can be attributed to the characteristics of the H_(2) heterolytic activation and the weak polarity of olefins.The driving effect of zeolite component towards CO conversion was demonstrated by microkinetic simulations,which is sensitive to reaction conditions like space velocity and reaction temperature.Under a fixed ratio of active sites between oxide and zeolite components,the concept of the“impossible trinity”of high CO conversion,high olefin selectivity,and high space velocity can thus be manifested.This work thus provides a comprehensive kinetic picture on the direct STO conversion,offering valuable insights for the design of each component of bifunctional catalysts and the optimization of reaction conditions.
文摘Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we find that the addition of moderate amounts of Ti forms a strong interaction with Fe compositions,modulating the Fe_(3)O_(4)and Fe_(5)C_(2)contents.Enhanced interaction leads to an increased Fe_(5)C_(2)/Fe_(3)O_(4)ratio,which in turn enhances the adsorption of reactants and intermediates,promoting CO hydrogenation to unsaturated alkyl groups and facilitating C–C coupling.Furthermore,the strong Fe-Ti interaction induces the preferential growth of Fe_(5)C_(2)into prismatic structures that expose the(020),(–112),and(311)facets,forming compact active interfacial sites with Fe_(3)O_(4)nanoparticles.These facet and interfacial effects significantly promote the synergistic coupling of the reverse water gas shift and Fischer-Tropsch reactions.The optimized 3K/FeTi catalyst with the highest Fe_(5)C_(2)/Fe_(3)O_(4)ratio of 3.6 achieves a 52.2%CO_(2)conversion rate,with 44.5%selectivity for C2–4=and 9.5%for CO,and the highest space-time yield of 412.0 mg gcat^(–1)h^(–1)for C_(2–4)=.
基金supported by the Key Project of Natural Science Foundation of Ningxia(NZ13010)the National Natural Science Foundation of China(21366025)~~
文摘Fe‐based catalysts for the production of light olefins via the Fischer‐Tropsch synthesis were modi‐fied by adding a Zn promoter using both microwave‐hydrothermal and impregnation methods. The physicochemical properties of the resulting catalysts were determined by scanning electron mi‐croscopy, the Brunauer‐Emmett‐Teller method, X‐ray diffraction, H2 temperature‐programed re‐duction and X‐ray photoelectron spectroscopy. The results demonstrate that the addition of a Zn promoter improves both the light olefin selectivity over the catalyst and the catalyst stability. The catalysts prepared via the impregnation method, which contain greater quantities of surface ZnO, exhibit severe carbon deposition following activity trials. In contrast, those materials synthesized using the microwave‐hydrothermal approach show improved dispersion of Zn and Fe phases and decreased carbon deposition, and so exhibit better CO conversion and stability.
基金Synfuels China Co.Ltd.for the financial and equipments support
文摘The ZSM-5 zeolite with an unusual snowflake-shaped morphology was hydrothermally synthesized for the first time,and compared with common ellipsoidal and boat-like shaped samples.These samples were characterized by N2 adsorption-desorption,X-ray fluorescence spectroscopy,scanning electron microscopy,X-ray diffraction,magic angle spinning nuclear magnetic resonance,temperature-programmed desorption of ammonia,and infrared spectroscopy of pyridine adsorption.The results suggest that the BET surface area and SiO2/Al2O3 ratio of these samples are similar,while the snowflake-shaped ZSM-5 zeolite possesses more of the（101） face,and distortion,dislocation,and asymmetry in the framework,resulting in a larger number of acid sites than the conventional samples.Catalysts for the methanol to olefin（MTO） reaction were prepared by loading Ca on the samples.The snowflake-shaped Ca/ZSM-5 zeolite exhibited excellent selectivity for total light olefin（72%） and propene（39%） in MTO.The catalytic performance influenced by the morphology can be mainly attributed to the snowflake-shaped ZSM-5 zeolite possessing distortion,dislocation,and asymmetry in the framework,and lower diffusion limitation than the conventional samples.
基金supported by the National Natural Science Foundation of China(21276041)the Program for New Century Excellent Talents in University of Ministry of Education of China(NCET-12-0079)+1 种基金the Natural Science Foundation of Liaoning Province(2015020200)the Fundamental Research Funds for the Central Universities(DUT15LK41)~~
文摘The catalytic performance of solid catalysts depends on the properties of the catalytically active sites and their accessibility to reactants, which are significantly affected by the microstructure（morphology, shape, size, texture, and surface structure） and surface chemistry（elemental components and chemical states）. The development of facile and efficient methods for tailoring the microstructure and surface chemistry is a hot topic in catalysis. This contribution reviews the state of the art in modulating the microstructure and surface chemistry of carbocatalysts by both bottom‐up and top‐down strategies and their use in the oxidative dehydrogenation（ODH） and direct dehydrogenation（DDH） of hydrocarbons including light alkanes and ethylbenzene to their corresponding olefins, important building blocks and chemicals like oxygenates. A concept of microstructure and surface chemistry tuning of the carbocatalyst for optimized catalytic performance and also for the fundamental understanding of the structure‐performance relationship is discussed. We also highlight the importance and challenges in modulating the microstructure and surface chemistry of carbocatalysts in ODH and DDH reactions of hydrocarbons for the highly‐efficient, energy‐saving,and clean production of their corresponding olefins.
文摘The density functional theory on the level of B3LYP/6-31G was empolyed to study the chain growth mechanism in polymerization process of α-linear olefin in TiCl3/AlEt2Cl catalytic system to synthesize drag reduction agent. Full parameter optimization without symmetry restrictions for reactants, products, the possible transition states, and intermediates was calculated. Vibration frequency was analyzed for all of stagnation points on the potential energy surface at the same theoretical level. The internal reaction coordinate was calculated from the transition states to reactants and products respectively. The results showed as flloes： （i） Coordination compounds were formed on the optimum configuration of TiCl3/AlEt2Cl.（ii） The transition states were formed. The energy di？erence between transition states and the coordination compounds was 40.687 kJ/mol. （iii） Double bond opened and Ti-C（4） bond fractured, and the polymerization was completed. The calculation results also showed that the chain growth mechanism did not essentially change with the increase of carbon atom number of α-linear olefin. From the relationship between polymerization activation energy and carbon atom number of the α-linear olefin, it can be seen that the α-linear olefin monomers with 6-10 carbon atoms had low activation energy and wide range. It was optimum to synthesize drag reduction agent by polymerization.
