Removing H_(2)S and CO_(2)is of great significance for natural gas purification.With excellent gas affinity and tunable structure,ionic liquids(ILs) have been regarded as nontrivial candidates for fabricating polymer-...Removing H_(2)S and CO_(2)is of great significance for natural gas purification.With excellent gas affinity and tunable structure,ionic liquids(ILs) have been regarded as nontrivial candidates for fabricating polymer-based membranes.Herein,we firstly reported the incorporation of protic ILs (PILs) having ether-rich and carboxylate sites (ECPILs) into poly(ether-block-amide)(Pebax) matrix for efficient separation H_(2)S and CO_(2)from CH_(4).Notably,the optimal permeability of H_(2)S reaches up to 4310 Barrer (40C,0.50 bar) in Pebax/ECPIL membranes,along with H_(2)S/CH_(4)and (H_(2)StCO_(2))/CH_(4)selectivity of 97.7 and 112.3,respectively.These values are increased by 1125%,160.8%and 145.9%compared to those in neat Pebax membrane.Additionally,the solubility and diffusion coefficients of the gases were measured,demonstrating that ECPIL can simultaneously strengthen the dissolution and diffusion of H_(2)S and CO_(2),thus elevating the permeability and permselectivity.By using quantum chemical calculations and FT-IR spectroscopy,the highly reversible multi-site hydrogen bonding interaction between ECPILs and H_(2)S was revealed,which is responsible for the fast permeation of H_(2)S and good selectivity.Furthermore,H_(2)S/CO_(2)/CH_(4)(3/3/94 mol/mol) ternary mixed gas can be efficiently and stably separated by Pebax/ECPIL membrane for at least 100 h.Overall,this work not only illustrates that PILs with ether-rich and carboxylate hydrogen bonding sites are outstanding materials for simultaneous removal of H_(2)S and CO_(2),but may also provide a novel insight into the design of membrane materials for natural gas upgrading.展开更多
A protic ionic liquid is designed and implemented for the first time as a solvent for a high energy density vanadium redox flow battery.Despite being less conductive than standa rd aqueous electrolytes,it is thermally...A protic ionic liquid is designed and implemented for the first time as a solvent for a high energy density vanadium redox flow battery.Despite being less conductive than standa rd aqueous electrolytes,it is thermally stable on a 100 ℃ temperature window,chemically stable for at least 60 days,equally viscous and dense with typical aqueous solvents and most importantly able to solubilize to 6 mol L^(-1) vanadium sulfate,thus increasing the VRFB energy density by a factor of 2.5.Electrochemical measurements revealed quasi-reversible redox transitions for both catholyte and anolyte at 25 ℃ while a proof-of-concept redox flow cell with the proposed electrolyte was tested for a total of 150 cycles at 25 ℃,showing an open circuit potential of 1.39 V and energy and coulombic efficiencies of 65% and 93%,respectively.What’s more,the battery can be equally cycled at 45℃ showing good thermal stability.This study underlines a new route to improve the energy-to-volume ratio of energy storage system.展开更多
The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than i...The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than in the conventional organic solvent. Furthermore, in the Diels-Alder reactions of 2- and 2,5-alkylfurans with N-alkylma- leimide, the reactivity increases by extending the alkyl chain length of N-alkylmaleimide. In addition, it was demon- strated that endo-selectivity increases when 2,5-disubstituted furans are used. These results will be explained by comparing the stability of the Diels-Alder adduct with that of the products obtained from the reactions of 2-substituted furans and 2,5-disubstituted furans.展开更多
The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)se...The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)separation,while high permeability and selectivity of membranes is a great challenge.In this study,the influence of two protic ILs with different anion([TMGH][Im]and[TMGH][PhO])on the CO_(2)separation performance of the prepared ILs/Pebax blended membranes were systematically investigated at different temperature.The results showed the CO_(2)permeability exhibits the rising trend for ILs/Pebax blended membranes with the increment of IL content.Especially,the[TMGH][Im]with low viscosity and high CO_(2)absorption capacity leads to the blended membranes showing better CO_(2)permeability and ideal CO_(2)selectivity than that of membranes with[TMGH][PhO]at high IL content.Besides,with operating temperature increasing,the gas permeability of 20%(mass)[TMGH][Im]/Pebax blended membrane increases due to the decreasing viscosity of IL and the rising chain mobility of polymer.Inversely,the gas selectivity shows decreasing trend because CO_(2)absorption capacity obviously decreased at higher temperature.展开更多
Four protic ionic liquids(ILs)were synthesized via a one-step method by using benzotriazole(BTA)and benzimidazole as cations,and benzenesulfonic acid and 2-naphthalenesulfonic acid(NSA)as anions.These ILs were used as...Four protic ionic liquids(ILs)were synthesized via a one-step method by using benzotriazole(BTA)and benzimidazole as cations,and benzenesulfonic acid and 2-naphthalenesulfonic acid(NSA)as anions.These ILs were used as green corrosion inhibitors for brass specimens in a nitric acid solution.The structure of the protic ILs was characterized by 1H-NMR,13C-NMR,and FT-IR spectroscopy.The effects of the IL structure,IL concentration,acid concentration,and corrosion time on the surface morphology of brass specimens and the inhibition efficiency(η%)of ILs were investigated by the weight loss method combined with SEM and EDS spectroscopy.Polarization curves and impedance spectroscopy were used to analyze the electrochemical corrosion inhibition mechanism of ILs.Results showed that IL synthesis was a proton transfer process,and the proton of the–SO3H group on NSA was deprived by BTA.IL[BTA][NSA],which had a high charge density and large conjugateπband,was the most effective inhibitor for brass corrosion.Theη%of[BTA][NSA]decreased with the increase in acid concentration and corrosion time,which showed an increment with the increase in[BTA][NSA]concentration.The higher theη%of[BTA][NSA]is,the smoother the surface of the brass specimens is,and the smaller the undistributed area of Cu element will be.Corrosion inhibiting mechanism from electrochemical analysis indicated that the addition of[BTA][NSA]increased the polarization resistance of the brass electrode significantly and suppressed both anodic and cathodic reactions.展开更多
Solvents are commonly added into protic ionic liquids(PILs)to reduce viscosity in practical applications.Understanding the relationship between the structure and properties of PILs mixed with solvents is also essentia...Solvents are commonly added into protic ionic liquids(PILs)to reduce viscosity in practical applications.Understanding the relationship between the structure and properties of PILs mixed with solvents is also essential for tailoring specific applications,however,such research is limited.In this study,we measured and compared the density,viscosity,and conductivity of three mixed systems:n-butylammonium butyrate ionic liquid(PIL)mixing with N-butyric acid(PrCOOH),PIL-N-butylamine(BuNH_(2)),and PIL-N-butanol(BuOH).Small-and wide-angle Xray scattering(S/WAXS),molecular dynamics(MD)simulation,and electron paramagnetic resonance(EPR)techniques were used to explore their inherent structural differences.The results indicate that the properties of the PIL-BuOH and PIL-PrCOOH systems exhibit more overall similarity in trends compared to the PIL-BuNH_(2)system.However,when the molar fraction of alcohol or acid exceeds 0.8,structural differences between the two systems lead to the differences in properties.The hydrogen bond network between the BuOH molecules outside the ion cluster leads to higher viscosity and conductivity than the PIL-PrCOOH system.However,the strong hydrogen bond between PrCOOH and anions will replace the position of cations and form spherical clusters.This research highlights how distinct structures influence diverse properties,providing deeper insights into the structure-property relationship.展开更多
The manipulation of hydrogen bonding within protic ionic liquids is conducive to conquering the robust hydrogen bonding interactions in cellulose for its effective dissolution,but it is a great challenge to establish ...The manipulation of hydrogen bonding within protic ionic liquids is conducive to conquering the robust hydrogen bonding interactions in cellulose for its effective dissolution,but it is a great challenge to establish the delicate bal-ance of hydrogen bonding network between solvent and cellulose.Herein,we proposed the concept of“hydrogen bond producers”for urea molecules in 1,1,3,3-tetramethylguanidinium methoxyacetate acid([TMGH][MAA])to enhance the dissolution of cellulose.The optimization of physicochemical properties for[TMGH][MAA]solvent as a function of urea concentration revealed a remark-able increase in cellulose solubility from 13%to 17%(w/w)by adding only 0.25 wt%urea,highlighting the efficiency of[TMGH][MAA]as a power-ful solvent for the dissolution of cellulose.The experimental and simulation results verified that the significant improvement on dissolution of cellulose was attributed to the hydrogen bonding interaction of urea molecules with ion pairs and part of free ions,reducing the interference with the active ions bonded to cellulose.Furthermore,the considerable enhancement on compre-hensive properties of regenerated cellulose films demonstrated the effectiveness of[TMGH][MAA]/urea solvent.The concept of“hydrogen bond producers”presented here opens a new avenue for significantly enhancing the dissolu-tion of natural cellulose,promoting the sustainable development in large-scale processing of cellulose.展开更多
Porous ionic liquids have demonstrated excellent performance in the field of separation,attributed to their high specific surface area and efficient mass transfer.Herein,task-specific protic porous ionic liquids(PPILs...Porous ionic liquids have demonstrated excellent performance in the field of separation,attributed to their high specific surface area and efficient mass transfer.Herein,task-specific protic porous ionic liquids(PPILs)were prepared by employing a novel one-step coupling neutralization reaction strategy for extractive desulfurization.The single-extraction efficiency of PPILs reached 75.0%for dibenzothiophene.Moreover,adding aromatic hydrocarbon interferents resulted in a slight decrease in the extraction efficiency of PPILs(from 45.2%to 37.3%,37.9%,and 33.5%),indicating the excellent extraction selectivity of PPILs.The experimental measurements and density functional theory calculations reveal that the surface channels of porous structures can selectively capture dibenzothiophene by the stronger electrophilicity(Eint(HS surface channel/DBT)=-39.8 kcal mol^(-1)),and the multiple extraction sites of ion pairs can effectively enrich and transport dibenzothiophene from the oil phase into PPILs throughπ...π,C-H...πand hydrogen bonds interactions.Furthermore,this straightforward synthetic strategy can be employed in preparing porous liquids,offering new possibilities for synthesizing PPILs with tailored functionalities.展开更多
In this study, the tribological behavior of an ammonium-based protic ionic liquid(PIL) as an additive in a base mineral oil(MO) is investigated on a steel–steel contact at room temperature and 100℃. Tri-[bis(2-hydro...In this study, the tribological behavior of an ammonium-based protic ionic liquid(PIL) as an additive in a base mineral oil(MO) is investigated on a steel–steel contact at room temperature and 100℃. Tri-[bis(2-hydroxyethylammonium)] citrate(DCi) was synthesized in a simple and low-cost way, and the ionic structure of DCi was confirmed by proton nuclear magnetic resonance(^(1)H NMR). The stability measurement of 1 wt% DCi to a MO was investigated, and the lubricating ability and anti-wear properties of DCi as an additive in MO were also examined using a custom-designed reciprocating ball-on-flat tribometer. Optical microscope and profilometry were used to obtain the worn morphology of the steel disks. Scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS) were carried out to investigate the wear mechanism and to analyze the surface interactions between the rubbing components. When 1 wt% DCi is added into the base MO, frictional performance is improved at both temperatures studied with a friction reduction of 29.0% and 35.5%, respectively. Moreover, the addition of 1 wt% DCi to MO reduced the wear volume 59.4% compared to the use of MO. An oxygen-richened tribolayer is confirmed by EDS on the disk surface when DCi was used as additive under 100℃.展开更多
Obtaining long-term stable and robust perovskite colloids solution remains an important scientific challenge due to the limited interaction between solvent and perovskite solutes.Here,we unveil the formation mechanism...Obtaining long-term stable and robust perovskite colloids solution remains an important scientific challenge due to the limited interaction between solvent and perovskite solutes.Here,we unveil the formation mechanism of chemically robust perovskite precursor solutions under ambient conditions using methylammonium acetate(CH3NH3•CH3COO,MAAc)protic ionic liquid(PIL)solvent.Tens of nanometers colloids are assembled on the molecular level via regular oriented gel-like lamellae with a mean thickness of 34.69 nm,width of 56.81 nm,and distance of 91.05 nm.展开更多
Ionic liquids(ILs)provide a promising way for efficient absorption and separation of ammonia(NH_(3))due to their extremely low vapor pressures and adjustable structures.However,the understanding of absorption mechanis...Ionic liquids(ILs)provide a promising way for efficient absorption and separation of ammonia(NH_(3))due to their extremely low vapor pressures and adjustable structures.However,the understanding of absorption mechanisms especially in terms of theoretical insights is still not very clear,which is crucial for designing targeted ILs.In this work,a universal method that integrates density functional theory and molecular dynamic simulations was proposed to study the mechanisms of NH_(3)absorption by protic ionic liquids(PILs).The results showed that the NH_(3)absorption performance of the imidazolium-based PILs([BIm][X],X=Tf_(2)N,SCN and NO_(3))is determined by not only the hydrogen bonding between the N atom in NH_(3)and the protic site(H–N_(3))on the cation but also the cation–anion interaction.With the increase in NH_(3)absorption capacity,the hydrogen bonding between[BIm][Tf_(2)N]and NH_(3)changed from orbital dominated to electrostatic dominated,so 3.0 mol NH_(3)per mol IL at 313.15 K and 0.10 MPa was further proved as a threshold for NH_(3)capacity of[BIm][Tf_(2)N]by the Gibbs free energy results,which agrees well with the experimental results.Furthermore,the anions of[BIm][X]could also compete with NH_(3)for interaction with H-N_(3)of the cation,which weakens the interaction between the cation and NH_(3)and then decreases the NH_(3)absorption ability of PILs.This study provides further understanding on NH_(3)absorption mechanisms with ILs,which will guide the design of novel functionalized ILs for NH_(3)separation and recovery.展开更多
Two protic pyrazolium ionic liquids(ILs)are synthesized and characterized by mass spectra(MS),1H NMR,13C NMR,and single-crystal X-ray diffraction.Then,their catalytic activity for the cycloaddition of PO and CO2 is in...Two protic pyrazolium ionic liquids(ILs)are synthesized and characterized by mass spectra(MS),1H NMR,13C NMR,and single-crystal X-ray diffraction.Then,their catalytic activity for the cycloaddition of PO and CO2 is investigated.Two protic pyrazolium ILs are the orthorhombic and triclinic systems of space groups Cmca and C2/c for HTMPzBr and HDMPzBr,respectively.They could catalyze the cycloaddition reaction of carbon dioxide(CO2)with epoxides(PO)to produce cyclic carbonate(PC)without any solvent and co-catalyst and show strong catalytic activity when the reaction temperature is over 110℃.展开更多
In the present study, new series of pyridinium carboxylate protic ionic liquids(PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C_1–C_3 forming pyridinium formate([C_5H_6N^+][HCOO^-]),...In the present study, new series of pyridinium carboxylate protic ionic liquids(PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C_1–C_3 forming pyridinium formate([C_5H_6N^+][HCOO^-]),pyridinium acetate([C_5H_6N^+][CH_3COO^-]) and pyridinium propionate([C_5H_6N^+][CH_3CH_2COO^-]) respectively.The physical properties namely, density, viscosity, surface tension(298.15–343.15) K, and refractive index(293.15–323.15) K were measured. Thermal properties namely, glass transition temperature, molar heat capacity, and thermal decomposition temperatures were also determined. The thermal expansivity was calculated using the experimental density data. The effect of increasing the alkyl chain length on the thermophysical properties of the pyridinium carboxylate PILs has been evaluated. As expected the physical properties i.e. density,viscosity, surface tension and refractive index of the investigated pyridinium carboxylates decreased with increasing temperature. In general pyridinium carboxylate PILs possessed low viscosity, high thermal stability and excellent hydrogen bonding capability, and these properties lead them to outperform conventional solvents employed for lignin dissolution.展开更多
基金sponsored by the National Natural Science Foundation of China (Nos. 22308145, 22208140, 22178159, 22078145)Natural Science Foundation of Jiangsu Province (BK20230791)Postgraduate Research Innovation Program of Jiangsu Province (KYCX24_0165)。
文摘Removing H_(2)S and CO_(2)is of great significance for natural gas purification.With excellent gas affinity and tunable structure,ionic liquids(ILs) have been regarded as nontrivial candidates for fabricating polymer-based membranes.Herein,we firstly reported the incorporation of protic ILs (PILs) having ether-rich and carboxylate sites (ECPILs) into poly(ether-block-amide)(Pebax) matrix for efficient separation H_(2)S and CO_(2)from CH_(4).Notably,the optimal permeability of H_(2)S reaches up to 4310 Barrer (40C,0.50 bar) in Pebax/ECPIL membranes,along with H_(2)S/CH_(4)and (H_(2)StCO_(2))/CH_(4)selectivity of 97.7 and 112.3,respectively.These values are increased by 1125%,160.8%and 145.9%compared to those in neat Pebax membrane.Additionally,the solubility and diffusion coefficients of the gases were measured,demonstrating that ECPIL can simultaneously strengthen the dissolution and diffusion of H_(2)S and CO_(2),thus elevating the permeability and permselectivity.By using quantum chemical calculations and FT-IR spectroscopy,the highly reversible multi-site hydrogen bonding interaction between ECPILs and H_(2)S was revealed,which is responsible for the fast permeation of H_(2)S and good selectivity.Furthermore,H_(2)S/CO_(2)/CH_(4)(3/3/94 mol/mol) ternary mixed gas can be efficiently and stably separated by Pebax/ECPIL membrane for at least 100 h.Overall,this work not only illustrates that PILs with ether-rich and carboxylate hydrogen bonding sites are outstanding materials for simultaneous removal of H_(2)S and CO_(2),but may also provide a novel insight into the design of membrane materials for natural gas upgrading.
基金"Le Studium Loire Valley Institute for Advanced Studies" and "Region Centre Val de Loire"through the "OBAMA" project under Lavoisier Ⅱ for financial support。
文摘A protic ionic liquid is designed and implemented for the first time as a solvent for a high energy density vanadium redox flow battery.Despite being less conductive than standa rd aqueous electrolytes,it is thermally stable on a 100 ℃ temperature window,chemically stable for at least 60 days,equally viscous and dense with typical aqueous solvents and most importantly able to solubilize to 6 mol L^(-1) vanadium sulfate,thus increasing the VRFB energy density by a factor of 2.5.Electrochemical measurements revealed quasi-reversible redox transitions for both catholyte and anolyte at 25 ℃ while a proof-of-concept redox flow cell with the proposed electrolyte was tested for a total of 150 cycles at 25 ℃,showing an open circuit potential of 1.39 V and energy and coulombic efficiencies of 65% and 93%,respectively.What’s more,the battery can be equally cycled at 45℃ showing good thermal stability.This study underlines a new route to improve the energy-to-volume ratio of energy storage system.
文摘The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than in the conventional organic solvent. Furthermore, in the Diels-Alder reactions of 2- and 2,5-alkylfurans with N-alkylma- leimide, the reactivity increases by extending the alkyl chain length of N-alkylmaleimide. In addition, it was demon- strated that endo-selectivity increases when 2,5-disubstituted furans are used. These results will be explained by comparing the stability of the Diels-Alder adduct with that of the products obtained from the reactions of 2-substituted furans and 2,5-disubstituted furans.
基金supported by the National Key R&D Program of China(2020YFA0710200)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(21921005)+2 种基金the Major Scientific and Technological Project of Shanxi Province of China(20201102005)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020047)the Innovation Academy for Green Manufacture,Chinese Academy of Sciences(IAGM2020C15)。
文摘The separation of carbon dioxide(CO_(2))is of great importance for environment protection and gas resource purification.The ionic liquids(ILs)-based gas separation membrane provides a new chance for efficient CO_(2)separation,while high permeability and selectivity of membranes is a great challenge.In this study,the influence of two protic ILs with different anion([TMGH][Im]and[TMGH][PhO])on the CO_(2)separation performance of the prepared ILs/Pebax blended membranes were systematically investigated at different temperature.The results showed the CO_(2)permeability exhibits the rising trend for ILs/Pebax blended membranes with the increment of IL content.Especially,the[TMGH][Im]with low viscosity and high CO_(2)absorption capacity leads to the blended membranes showing better CO_(2)permeability and ideal CO_(2)selectivity than that of membranes with[TMGH][PhO]at high IL content.Besides,with operating temperature increasing,the gas permeability of 20%(mass)[TMGH][Im]/Pebax blended membrane increases due to the decreasing viscosity of IL and the rising chain mobility of polymer.Inversely,the gas selectivity shows decreasing trend because CO_(2)absorption capacity obviously decreased at higher temperature.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(grant no.21802047)and the Scientific Research Funds of Huaqiao University(grant no.600005-Z17Y0073),Xiamen,China.
文摘Four protic ionic liquids(ILs)were synthesized via a one-step method by using benzotriazole(BTA)and benzimidazole as cations,and benzenesulfonic acid and 2-naphthalenesulfonic acid(NSA)as anions.These ILs were used as green corrosion inhibitors for brass specimens in a nitric acid solution.The structure of the protic ILs was characterized by 1H-NMR,13C-NMR,and FT-IR spectroscopy.The effects of the IL structure,IL concentration,acid concentration,and corrosion time on the surface morphology of brass specimens and the inhibition efficiency(η%)of ILs were investigated by the weight loss method combined with SEM and EDS spectroscopy.Polarization curves and impedance spectroscopy were used to analyze the electrochemical corrosion inhibition mechanism of ILs.Results showed that IL synthesis was a proton transfer process,and the proton of the–SO3H group on NSA was deprived by BTA.IL[BTA][NSA],which had a high charge density and large conjugateπband,was the most effective inhibitor for brass corrosion.Theη%of[BTA][NSA]decreased with the increase in acid concentration and corrosion time,which showed an increment with the increase in[BTA][NSA]concentration.The higher theη%of[BTA][NSA]is,the smoother the surface of the brass specimens is,and the smaller the undistributed area of Cu element will be.Corrosion inhibiting mechanism from electrochemical analysis indicated that the addition of[BTA][NSA]increased the polarization resistance of the brass electrode significantly and suppressed both anodic and cathodic reactions.
基金supported by the National Natural Science Foundation of China(No.22073081)the Fundamental Research Funds for the Central Universities。
文摘Solvents are commonly added into protic ionic liquids(PILs)to reduce viscosity in practical applications.Understanding the relationship between the structure and properties of PILs mixed with solvents is also essential for tailoring specific applications,however,such research is limited.In this study,we measured and compared the density,viscosity,and conductivity of three mixed systems:n-butylammonium butyrate ionic liquid(PIL)mixing with N-butyric acid(PrCOOH),PIL-N-butylamine(BuNH_(2)),and PIL-N-butanol(BuOH).Small-and wide-angle Xray scattering(S/WAXS),molecular dynamics(MD)simulation,and electron paramagnetic resonance(EPR)techniques were used to explore their inherent structural differences.The results indicate that the properties of the PIL-BuOH and PIL-PrCOOH systems exhibit more overall similarity in trends compared to the PIL-BuNH_(2)system.However,when the molar fraction of alcohol or acid exceeds 0.8,structural differences between the two systems lead to the differences in properties.The hydrogen bond network between the BuOH molecules outside the ion cluster leads to higher viscosity and conductivity than the PIL-PrCOOH system.However,the strong hydrogen bond between PrCOOH and anions will replace the position of cations and form spherical clusters.This research highlights how distinct structures influence diverse properties,providing deeper insights into the structure-property relationship.
基金Science and Technology Department of Sichuan Province,Grant/Award Number:2022YFH0094National Natural Science Foundation of China,Grant/Award Numbers:51973141,52033005,U21A2090。
文摘The manipulation of hydrogen bonding within protic ionic liquids is conducive to conquering the robust hydrogen bonding interactions in cellulose for its effective dissolution,but it is a great challenge to establish the delicate bal-ance of hydrogen bonding network between solvent and cellulose.Herein,we proposed the concept of“hydrogen bond producers”for urea molecules in 1,1,3,3-tetramethylguanidinium methoxyacetate acid([TMGH][MAA])to enhance the dissolution of cellulose.The optimization of physicochemical properties for[TMGH][MAA]solvent as a function of urea concentration revealed a remark-able increase in cellulose solubility from 13%to 17%(w/w)by adding only 0.25 wt%urea,highlighting the efficiency of[TMGH][MAA]as a power-ful solvent for the dissolution of cellulose.The experimental and simulation results verified that the significant improvement on dissolution of cellulose was attributed to the hydrogen bonding interaction of urea molecules with ion pairs and part of free ions,reducing the interference with the active ions bonded to cellulose.Furthermore,the considerable enhancement on compre-hensive properties of regenerated cellulose films demonstrated the effectiveness of[TMGH][MAA]/urea solvent.The concept of“hydrogen bond producers”presented here opens a new avenue for significantly enhancing the dissolu-tion of natural cellulose,promoting the sustainable development in large-scale processing of cellulose.
基金financially supported by the National Natural Science Foundation of China (Nos.22078135,21808092,21978119,22202088)。
文摘Porous ionic liquids have demonstrated excellent performance in the field of separation,attributed to their high specific surface area and efficient mass transfer.Herein,task-specific protic porous ionic liquids(PPILs)were prepared by employing a novel one-step coupling neutralization reaction strategy for extractive desulfurization.The single-extraction efficiency of PPILs reached 75.0%for dibenzothiophene.Moreover,adding aromatic hydrocarbon interferents resulted in a slight decrease in the extraction efficiency of PPILs(from 45.2%to 37.3%,37.9%,and 33.5%),indicating the excellent extraction selectivity of PPILs.The experimental measurements and density functional theory calculations reveal that the surface channels of porous structures can selectively capture dibenzothiophene by the stronger electrophilicity(Eint(HS surface channel/DBT)=-39.8 kcal mol^(-1)),and the multiple extraction sites of ion pairs can effectively enrich and transport dibenzothiophene from the oil phase into PPILs throughπ...π,C-H...πand hydrogen bonds interactions.Furthermore,this straightforward synthetic strategy can be employed in preparing porous liquids,offering new possibilities for synthesizing PPILs with tailored functionalities.
文摘In this study, the tribological behavior of an ammonium-based protic ionic liquid(PIL) as an additive in a base mineral oil(MO) is investigated on a steel–steel contact at room temperature and 100℃. Tri-[bis(2-hydroxyethylammonium)] citrate(DCi) was synthesized in a simple and low-cost way, and the ionic structure of DCi was confirmed by proton nuclear magnetic resonance(^(1)H NMR). The stability measurement of 1 wt% DCi to a MO was investigated, and the lubricating ability and anti-wear properties of DCi as an additive in MO were also examined using a custom-designed reciprocating ball-on-flat tribometer. Optical microscope and profilometry were used to obtain the worn morphology of the steel disks. Scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS) were carried out to investigate the wear mechanism and to analyze the surface interactions between the rubbing components. When 1 wt% DCi is added into the base MO, frictional performance is improved at both temperatures studied with a friction reduction of 29.0% and 35.5%, respectively. Moreover, the addition of 1 wt% DCi to MO reduced the wear volume 59.4% compared to the use of MO. An oxygen-richened tribolayer is confirmed by EDS on the disk surface when DCi was used as additive under 100℃.
基金supported by the Natural Science Foundation of China(grant nos.51602149,61705102,61605073,61935017,62175268,and 22022309)the Macao Science and Technology Development Fund(grant no.FDCT-0044/2020/A1)+3 种基金research grants(grant nos.MYRG2018-00148-IAPME and MYRG2020-00151-IAPME)from the University of Macao and Natural Science Foundation of Guangdong Province,China(grant no.2019A1515012186)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(grant no.2019B121205002)Shenzhen-Hong Kong-Macao Science and Technology Innovation Project(Category C)(grant no.SGDX2020110309360100)and the Young 1000 Talents Global Recruitment Program of China.
文摘Obtaining long-term stable and robust perovskite colloids solution remains an important scientific challenge due to the limited interaction between solvent and perovskite solutes.Here,we unveil the formation mechanism of chemically robust perovskite precursor solutions under ambient conditions using methylammonium acetate(CH3NH3•CH3COO,MAAc)protic ionic liquid(PIL)solvent.Tens of nanometers colloids are assembled on the molecular level via regular oriented gel-like lamellae with a mean thickness of 34.69 nm,width of 56.81 nm,and distance of 91.05 nm.
基金financially supported by the National Key R&D Program of China(2020YFA0710200)the National Natural Science Foundation of China(22122814,21890764 and 21838010)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2018064)the Major Scientific and Technological Innovation Project of Shandong Province of China(2019JZZY010518).
文摘Ionic liquids(ILs)provide a promising way for efficient absorption and separation of ammonia(NH_(3))due to their extremely low vapor pressures and adjustable structures.However,the understanding of absorption mechanisms especially in terms of theoretical insights is still not very clear,which is crucial for designing targeted ILs.In this work,a universal method that integrates density functional theory and molecular dynamic simulations was proposed to study the mechanisms of NH_(3)absorption by protic ionic liquids(PILs).The results showed that the NH_(3)absorption performance of the imidazolium-based PILs([BIm][X],X=Tf_(2)N,SCN and NO_(3))is determined by not only the hydrogen bonding between the N atom in NH_(3)and the protic site(H–N_(3))on the cation but also the cation–anion interaction.With the increase in NH_(3)absorption capacity,the hydrogen bonding between[BIm][Tf_(2)N]and NH_(3)changed from orbital dominated to electrostatic dominated,so 3.0 mol NH_(3)per mol IL at 313.15 K and 0.10 MPa was further proved as a threshold for NH_(3)capacity of[BIm][Tf_(2)N]by the Gibbs free energy results,which agrees well with the experimental results.Furthermore,the anions of[BIm][X]could also compete with NH_(3)for interaction with H-N_(3)of the cation,which weakens the interaction between the cation and NH_(3)and then decreases the NH_(3)absorption ability of PILs.This study provides further understanding on NH_(3)absorption mechanisms with ILs,which will guide the design of novel functionalized ILs for NH_(3)separation and recovery.
基金Supported by the Key Scientific Research Plan Projects of Henan Province(No.18A150024)Innovation and entrepreneurship support program for college students of Minsheng College,Henan University(No.MSCXCY2018006)。
文摘Two protic pyrazolium ionic liquids(ILs)are synthesized and characterized by mass spectra(MS),1H NMR,13C NMR,and single-crystal X-ray diffraction.Then,their catalytic activity for the cycloaddition of PO and CO2 is investigated.Two protic pyrazolium ILs are the orthorhombic and triclinic systems of space groups Cmca and C2/c for HTMPzBr and HDMPzBr,respectively.They could catalyze the cycloaddition reaction of carbon dioxide(CO2)with epoxides(PO)to produce cyclic carbonate(PC)without any solvent and co-catalyst and show strong catalytic activity when the reaction temperature is over 110℃.
基金the National Natural Science Foundation of China(21176033,21006007,21203193,21273029)Research Foundation for the Doctoral Program of Higher Education of China(20120042110024)~~
文摘In the present study, new series of pyridinium carboxylate protic ionic liquids(PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C_1–C_3 forming pyridinium formate([C_5H_6N^+][HCOO^-]),pyridinium acetate([C_5H_6N^+][CH_3COO^-]) and pyridinium propionate([C_5H_6N^+][CH_3CH_2COO^-]) respectively.The physical properties namely, density, viscosity, surface tension(298.15–343.15) K, and refractive index(293.15–323.15) K were measured. Thermal properties namely, glass transition temperature, molar heat capacity, and thermal decomposition temperatures were also determined. The thermal expansivity was calculated using the experimental density data. The effect of increasing the alkyl chain length on the thermophysical properties of the pyridinium carboxylate PILs has been evaluated. As expected the physical properties i.e. density,viscosity, surface tension and refractive index of the investigated pyridinium carboxylates decreased with increasing temperature. In general pyridinium carboxylate PILs possessed low viscosity, high thermal stability and excellent hydrogen bonding capability, and these properties lead them to outperform conventional solvents employed for lignin dissolution.
