Photoinduced[2+2]cycloaddition of biomass-derived cycloolefin is a promising approach to synthesize high-energy bio-fuels,however,the conversion efficiency and selectivity are still low.Herein,we provide an acid-promo...Photoinduced[2+2]cycloaddition of biomass-derived cycloolefin is a promising approach to synthesize high-energy bio-fuels,however,the conversion efficiency and selectivity are still low.Herein,we provide an acid-promoted photocycloaddition approach to synthesize a new kind of spiral fuel from biomass-derived cyclohexanone (CHOE) and camphene (CPE).BrΦnsted acids show higher catalytic activity than Lewis acids,and acetic acid (HOAc) possesses the best catalytic performance,with CHOE conversion up to 99.1%.Meanwhile,the HOAc-catalytic effect has been confirmed for[2+2]photocycloaddition of other biomass-derived ketenes and olefins.The catalytic mechanism and dynamics have been investigated,and show that HOAc can bond with C=O groups of CHOE to form H–CHOE complex,which leads to higher light adsorption and longer triplet lifetime.Meanwhile,H–CHOE complex reduces the energy gap between CHOE LUMO and CPE HOMO,shortens the distance of ring-forming atoms,and then decreases the energy barrier (from 103.3 kcal mol^(-1)to 95.8 kcal mol^(-1)) of rate-limiting step.After hydrodeoxygenation,the targeted bio-spiral fuel shows high density of 0.992 g cm^(-3),high neat heat of combustion of 41.89 MJ L^(-1),low kinetic viscosity of 5.69 mm^(2)s^(-1)at 20℃,which is very promising to serve as high-performance aerospace fuel.展开更多
Olefin oligomerization reaction catalyzed by new catalyst systems(a Bronsted‐acidic ionic liquid as the main catalyst and tricaprylylmethylammonium chloride as the co‐catalyst)has been investigat‐ed.The synthesized...Olefin oligomerization reaction catalyzed by new catalyst systems(a Bronsted‐acidic ionic liquid as the main catalyst and tricaprylylmethylammonium chloride as the co‐catalyst)has been investigat‐ed.The synthesized Bronsted acidic ionic liquids were characterized by Fourier transform infrared spectroscopy(FT‐IR),ultraviolet‐visible spectroscopy(UV),^(1)H nuclear magnetic resonance(NMR),and^13 C NMR to analyze their structures and acidities.The influence of different ionic liquids,ionic liquid loading,different co‐catalysts,catalyst ratios(mole ratio of ionic liquid to co‐catalyst),reac‐tion time,pressure,temperature,solvent,source of reactants,and the recycling of catalyst systems was studied.Among the synthesized ionic liquids,1‐(4‐sulfonic acid)butyl‐3‐hexylimidazolium hydrogen sulfate([HIMBs]HSO4)exhibited the best catalytic activity under the tested reaction con‐ditions.The conversion of isobutene and selectivity of trimers were 83.21%and 35.80%,respec‐tively,at the optimum reaction conditions.Furthermore,the catalyst system can be easily separated and reused;a feasible reaction mechanism is proposed on the basis of the distribution of experi‐mental products.展开更多
In this study,cyclohexene was used as a representative of olefin and catalyzed by CeY zeolites in a fixedbed reactor under mild conditions,and the influence of Ce species in hydride transfer reaction over CeY zeolites...In this study,cyclohexene was used as a representative of olefin and catalyzed by CeY zeolites in a fixedbed reactor under mild conditions,and the influence of Ce species in hydride transfer reaction over CeY zeolites was evaluated.CeY zeolites show more excellent hydride transfer properties than HY zeolite.Based on the results of almost identical Bronsted acid properties but not the product distributions for 0.075 CeY and 0.075 CeY(DC)samples,it should be suggested that the Bronsted acid strength and density are not the deciding factors to the hydride transfer reaction.A unique band at 1442 cm^-1 in situ FTIR spectroscopy spectra are assigned to pyridine complexes bonded to a class of active Ce species that could reversibly migrate from the core of SOD cages to its 6-rings mouth towards the supercages.These results provide valuable information that these active Ce species should play a synergistic role with the Bronsted acid sites in enhancing the hydride transfer reaction with a bimolecular mechanism over CeY zeolites.展开更多
A series of Bronsted acidic ionic liquids（ILs） were prepared and used for Biginelli-type condensation reaction among aromatic aldehydes, urea or thiourea and cyclopentanone. Through this reaction, the synthesis of v...A series of Bronsted acidic ionic liquids（ILs） were prepared and used for Biginelli-type condensation reaction among aromatic aldehydes, urea or thiourea and cyclopentanone. Through this reaction, the synthesis of various pyrimidinones could be achieved. Of interest, it was found that the reaction was efficiently catalyzed by a novel, eco-friendly functionalized IL [C3SO3HDoim]HSO4, which could be reused for at least 7 times without significantly loss of catalytic activity. The reaction proceeded efficiently at 80℃ to afford the desired products in good yield（up to 96%）. In addition, a possible mechanism that accounted for the IL [C3SO3HDoim]HSO4-catalyzed reaction was proposed.展开更多
Five Br?nsted acidic ionic liquids(ILs) were prepared and characterized by FT-IR,~1H NMR and ^(13)C NMR. Their catalytic activities for the synthesis of 2-propanol(IPOH) via transesterification of isopropyl acetate(IP...Five Br?nsted acidic ionic liquids(ILs) were prepared and characterized by FT-IR,~1H NMR and ^(13)C NMR. Their catalytic activities for the synthesis of 2-propanol(IPOH) via transesterification of isopropyl acetate(IPAc) with methanol(Me OH) were investigated. Among all the tested ILs, [Ps-mim]HSO_4 performed best and was used as catalyst for further studies. The reaction kinetics were carried out to correlate the parameters in a homogeneous second order kinetic model. It has been found that there is close agreement between the calculated and experimental values. The high-pressure batch reactive distillation experimental apparatus was set up in order to enhance the conversion of IPAc. A high conversion of IPAc of 99.4% was obtained under the optimal reaction conditions. The catalyst [Ps-mim]HSO_4 can be recycled easily by a rotary evaporator and reused without any further treatment. The catalyst had been repeatedly used for four times and no obvious changes in the structure of catalyst could be observed.展开更多
A series of condensation reactions of unmodified ketones and aromatic aldehydes to prepare α,β-unsaturated carbonyl compounds by means of Aldol reactions in Bronsted acid ionic liquids（BAILs）was explored.1-Butyl-3...A series of condensation reactions of unmodified ketones and aromatic aldehydes to prepare α,β-unsaturated carbonyl compounds by means of Aldol reactions in Bronsted acid ionic liquids（BAILs）was explored.1-Butyl-3-methylimidazolium hydrogen sulphate（BMImHSO4）acting as an effective media and catalyst in aldol reactions was compared with other BAILs,with the advantages of high conversion and selectivity.The product was easily isolated and the left ionic liquid can be readily recovered and reused at least 3 times with almost the same efficiency.The scope and limitation of the present method were explored and the possible catalytic mechanism was speculated.展开更多
4-（Succinimido）-1-butane sulfonic acid as an efficient and reusable Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions.The catalyst can be prepared by mixing succin...4-（Succinimido）-1-butane sulfonic acid as an efficient and reusable Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions.The catalyst can be prepared by mixing succinimide and 1,4-butanesultone that is more simple and safer than the preparation of succinimide sulfonic acid.This method has the advantages of high yield,clean reaction,simple methodology and short reaction time.The catalyst could be recycled without significant loss of activity.展开更多
Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amoun...Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amount of undesirable byproducts under mild reaction conditions, a low environmental load process was developed. Beckmann rearrangements of cyclohexanone oxime and cyclooctanone oxime were achieved using a combination of a Bronsted acid and cobalt tetra-fluoroborate hexahydrate. Various Bronsted acid catalysts (10 - 20 mol%) were used to obtain the corresponding lactams in high yields at 80℃.展开更多
Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electro...Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.展开更多
Some oxindoles derivatives are synthesized from the condensation of indoles with isatins in the presence of green and recycable catalyst [（CH2）4SO3HMIM] [HSO4] in water at room temperature.
Over the past two decades, research on transforming lignocellulosic biomass into small molecule chemicals byusing catalytic liquefaction has made great progress. Notably, in recent years it has been found the producti...Over the past two decades, research on transforming lignocellulosic biomass into small molecule chemicals byusing catalytic liquefaction has made great progress. Notably, in recent years it has been found the production of smallmolecule chemicals through directional liquefaction of lignocellulosic biomass. Understanding the liquefactionmechanism of lignocellulosic biomass is highly important. In this review, the liquefaction mechanism of lignocellulosicbiomass and model compounds of cellulose are described, and some problems and suggestions to address them aredescribed.展开更多
基金the support from National Key R&D Program of China (2021YFC2103704)the National Natural Science Foundation of China (22222808)+4 种基金the Natural Science Foundation of Shandong Province (ZR2023QB152)the Youth Innovation Team Plan of Shandong Province (2022KJ270)the China National Postdoctoral Program for Innovative Talents (BX20240251)the Aeronautical Science Foundation of China (2023Z073048003)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘Photoinduced[2+2]cycloaddition of biomass-derived cycloolefin is a promising approach to synthesize high-energy bio-fuels,however,the conversion efficiency and selectivity are still low.Herein,we provide an acid-promoted photocycloaddition approach to synthesize a new kind of spiral fuel from biomass-derived cyclohexanone (CHOE) and camphene (CPE).BrΦnsted acids show higher catalytic activity than Lewis acids,and acetic acid (HOAc) possesses the best catalytic performance,with CHOE conversion up to 99.1%.Meanwhile,the HOAc-catalytic effect has been confirmed for[2+2]photocycloaddition of other biomass-derived ketenes and olefins.The catalytic mechanism and dynamics have been investigated,and show that HOAc can bond with C=O groups of CHOE to form H–CHOE complex,which leads to higher light adsorption and longer triplet lifetime.Meanwhile,H–CHOE complex reduces the energy gap between CHOE LUMO and CPE HOMO,shortens the distance of ring-forming atoms,and then decreases the energy barrier (from 103.3 kcal mol^(-1)to 95.8 kcal mol^(-1)) of rate-limiting step.After hydrodeoxygenation,the targeted bio-spiral fuel shows high density of 0.992 g cm^(-3),high neat heat of combustion of 41.89 MJ L^(-1),low kinetic viscosity of 5.69 mm^(2)s^(-1)at 20℃,which is very promising to serve as high-performance aerospace fuel.
文摘Olefin oligomerization reaction catalyzed by new catalyst systems(a Bronsted‐acidic ionic liquid as the main catalyst and tricaprylylmethylammonium chloride as the co‐catalyst)has been investigat‐ed.The synthesized Bronsted acidic ionic liquids were characterized by Fourier transform infrared spectroscopy(FT‐IR),ultraviolet‐visible spectroscopy(UV),^(1)H nuclear magnetic resonance(NMR),and^13 C NMR to analyze their structures and acidities.The influence of different ionic liquids,ionic liquid loading,different co‐catalysts,catalyst ratios(mole ratio of ionic liquid to co‐catalyst),reac‐tion time,pressure,temperature,solvent,source of reactants,and the recycling of catalyst systems was studied.Among the synthesized ionic liquids,1‐(4‐sulfonic acid)butyl‐3‐hexylimidazolium hydrogen sulfate([HIMBs]HSO4)exhibited the best catalytic activity under the tested reaction con‐ditions.The conversion of isobutene and selectivity of trimers were 83.21%and 35.80%,respec‐tively,at the optimum reaction conditions.Furthermore,the catalyst system can be easily separated and reused;a feasible reaction mechanism is proposed on the basis of the distribution of experi‐mental products.
基金Project supported by the National Natural Science Foundation of China(21902068,U1662135)PetroChina Company Limited(KYWX-18-011)Scientific Research Project of Education Department of Liaoning Province(L2019035)。
文摘In this study,cyclohexene was used as a representative of olefin and catalyzed by CeY zeolites in a fixedbed reactor under mild conditions,and the influence of Ce species in hydride transfer reaction over CeY zeolites was evaluated.CeY zeolites show more excellent hydride transfer properties than HY zeolite.Based on the results of almost identical Bronsted acid properties but not the product distributions for 0.075 CeY and 0.075 CeY(DC)samples,it should be suggested that the Bronsted acid strength and density are not the deciding factors to the hydride transfer reaction.A unique band at 1442 cm^-1 in situ FTIR spectroscopy spectra are assigned to pyridine complexes bonded to a class of active Ce species that could reversibly migrate from the core of SOD cages to its 6-rings mouth towards the supercages.These results provide valuable information that these active Ce species should play a synergistic role with the Bronsted acid sites in enhancing the hydride transfer reaction with a bimolecular mechanism over CeY zeolites.
文摘A series of Bronsted acidic ionic liquids（ILs） were prepared and used for Biginelli-type condensation reaction among aromatic aldehydes, urea or thiourea and cyclopentanone. Through this reaction, the synthesis of various pyrimidinones could be achieved. Of interest, it was found that the reaction was efficiently catalyzed by a novel, eco-friendly functionalized IL [C3SO3HDoim]HSO4, which could be reused for at least 7 times without significantly loss of catalytic activity. The reaction proceeded efficiently at 80℃ to afford the desired products in good yield（up to 96%）. In addition, a possible mechanism that accounted for the IL [C3SO3HDoim]HSO4-catalyzed reaction was proposed.
基金Supported by the National Natural Science Foundation of China(21576053,91534106,21306025)the International S&T Cooperation Program of China(2013DFR90540)+3 种基金the Science Foundation of Distinguished Young Scholars of Fujian(2014J06004)the New Century Excellent Talents in Fujian Province University(JA12014)the Natural Science Foundation of Fujian Province(2016J01689)the Key Project of Fujian Provincial Department of Science and Technology(2014Y0066)
文摘Five Br?nsted acidic ionic liquids(ILs) were prepared and characterized by FT-IR,~1H NMR and ^(13)C NMR. Their catalytic activities for the synthesis of 2-propanol(IPOH) via transesterification of isopropyl acetate(IPAc) with methanol(Me OH) were investigated. Among all the tested ILs, [Ps-mim]HSO_4 performed best and was used as catalyst for further studies. The reaction kinetics were carried out to correlate the parameters in a homogeneous second order kinetic model. It has been found that there is close agreement between the calculated and experimental values. The high-pressure batch reactive distillation experimental apparatus was set up in order to enhance the conversion of IPAc. A high conversion of IPAc of 99.4% was obtained under the optimal reaction conditions. The catalyst [Ps-mim]HSO_4 can be recycled easily by a rotary evaporator and reused without any further treatment. The catalyst had been repeatedly used for four times and no obvious changes in the structure of catalyst could be observed.
基金Supported by National Natural Science Foundation of China(No.20576026)Environmental Engineering Key Subject of He-bei Province,China.
文摘A series of condensation reactions of unmodified ketones and aromatic aldehydes to prepare α,β-unsaturated carbonyl compounds by means of Aldol reactions in Bronsted acid ionic liquids（BAILs）was explored.1-Butyl-3-methylimidazolium hydrogen sulphate（BMImHSO4）acting as an effective media and catalyst in aldol reactions was compared with other BAILs,with the advantages of high conversion and selectivity.The product was easily isolated and the left ionic liquid can be readily recovered and reused at least 3 times with almost the same efficiency.The scope and limitation of the present method were explored and the possible catalytic mechanism was speculated.
文摘4-（Succinimido）-1-butane sulfonic acid as an efficient and reusable Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions.The catalyst can be prepared by mixing succinimide and 1,4-butanesultone that is more simple and safer than the preparation of succinimide sulfonic acid.This method has the advantages of high yield,clean reaction,simple methodology and short reaction time.The catalyst could be recycled without significant loss of activity.
文摘Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amount of undesirable byproducts under mild reaction conditions, a low environmental load process was developed. Beckmann rearrangements of cyclohexanone oxime and cyclooctanone oxime were achieved using a combination of a Bronsted acid and cobalt tetra-fluoroborate hexahydrate. Various Bronsted acid catalysts (10 - 20 mol%) were used to obtain the corresponding lactams in high yields at 80℃.
基金the financial support from the National Natural Science Foundation of China(52172110,52472231,52311530113)Shanghai"Science and Technology Innovation Action Plan"intergovernmental international science and technology cooperation project(23520710600)+1 种基金Science and Technology Commission of Shanghai Municipality(22DZ1205600)the Central Guidance on Science and Technology Development Fund of Zhejiang Province(2024ZY01011)。
文摘Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.
文摘Some oxindoles derivatives are synthesized from the condensation of indoles with isatins in the presence of green and recycable catalyst [（CH2）4SO3HMIM] [HSO4] in water at room temperature.
文摘Over the past two decades, research on transforming lignocellulosic biomass into small molecule chemicals byusing catalytic liquefaction has made great progress. Notably, in recent years it has been found the production of smallmolecule chemicals through directional liquefaction of lignocellulosic biomass. Understanding the liquefactionmechanism of lignocellulosic biomass is highly important. In this review, the liquefaction mechanism of lignocellulosicbiomass and model compounds of cellulose are described, and some problems and suggestions to address them aredescribed.
