Anion exchange membrane(AEM)fuel cells require membranes with a balance of high conductivity and durability.In this work,a novel bi-crown-ether modified piperidine structure was designed and synthesized,which was then...Anion exchange membrane(AEM)fuel cells require membranes with a balance of high conductivity and durability.In this work,a novel bi-crown-ether modified piperidine structure was designed and synthesized,which was then introduced into the side chain of poly(arylene piperidinium),making a unique bi-crown-ether modified bi-piperidinium side chain grafted polymer for AEM fabrication.The double crown ether units enhanced cation–water interactions and promoted microphase separation,thereby forming efficient hydroxide ion transport channels.The resulting membrane exhibited high water uptake,well-defined ion clusters,and a hydroxide conductivity of 123 mS cm^(-1) at 80℃ with an ion exchange capacity(IEC)of 1.56 mmol g^(-1).After alkaline treatment in 1 M NaOH at 80℃ for 960 h,the membrane retained~85%of its initial conductivity,demonstrating excellent chemical stability.In H2/O2 fuel cell tests at 60℃ ,the membrane achieved a peak power density of 558 mW cm-2 at 1040 mA cm-2.These findings highlight the potential of bi-crown-ether modified piperidinium side chain grafting as an effective strategy to enhance ion conduction properties of AEMs for fuel cell applications.展开更多
The separation of lithium isotopes (^(6)Li and ^(7)Li) is of great importance for the nuclear industry.The lithium amalgam method is the only lithium isotopes separation process in industry,and the extensive use of me...The separation of lithium isotopes (^(6)Li and ^(7)Li) is of great importance for the nuclear industry.The lithium amalgam method is the only lithium isotopes separation process in industry,and the extensive use of mercury has raised concerns about its potential environmental hazards,which have prompted the search for more efficient and environmentally friendly alternatives.Crown ethers can bind lithium ions highly selectively and separate lithium isotopes effectively.A chemical exchange-based lithium isotopes separation method using crown ether decorated materials could be a viable and cost-effective alternative to the lithium amalgam method.In this review,we provide a systematic summary of the recent advances in lithium isotopes separation using crown ethers decorated materials.展开更多
In recent years,with the rapid developme nt of the econo my and society,pollution of valuable metal ions in wastewater has become a major challenge to environmental sustainability.In order to solve the pollution cause...In recent years,with the rapid developme nt of the econo my and society,pollution of valuable metal ions in wastewater has become a major challenge to environmental sustainability.In order to solve the pollution caused by metal ions,researchers have conducted continuous re searches and explored various re mediation methods.Crown ether has attracted great attention because of its ionic radius and cavity size matching well with metal ions,which makes it have the ability to selectively complex metal ions.This unique property enables the directed removal and recovery of metal ions and makes crown ethers increasingly popular in extraction and separation processes.In this paper,the research progress of crown ethers in the extraction and separation of valuable metal ions was reviewed,with emphasis on the principles,extraction systems and the key factors affecting the extraction process.This study can provide some technical support for the application of separation and extraction of valuable metal ions by crown ether.展开更多
Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high...Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.展开更多
A new stable salen Schiff base cobalt and crown ether sodium complex （SalCo-NaB18C6） was prepared through copolymerization. This copolymer complex was applied to catalytic oxidation of hydrocarbon compound with mole...A new stable salen Schiff base cobalt and crown ether sodium complex （SalCo-NaB18C6） was prepared through copolymerization. This copolymer complex was applied to catalytic oxidation of hydrocarbon compound with molecular oxygen without reductant, which was shown the higher activity and selectivity for ketone, and reused effectively.展开更多
The cross-linking of crown ether-SE-54 in fused-silica capillary columns were initiated by dicumyl peroxide(DCUP),azo-bis-isobutyronitrile (AIBN)and ozone(O_3).Parameters of evaluation such as polarity,selectivity, ph...The cross-linking of crown ether-SE-54 in fused-silica capillary columns were initiated by dicumyl peroxide(DCUP),azo-bis-isobutyronitrile (AIBN)and ozone(O_3).Parameters of evaluation such as polarity,selectivity, phase transition temperature and thermal stability were studied and compared with those of poly(crown ether)stationary phase.展开更多
A new type of crown ether cross-linked chitosan was synthesized by the reaction of chitosan with 4,4′-dibromodibenzo-18-crown-6 (Br-DBC). Its token structure was analyzed with FT-IR and NMR and the adsorption behavio...A new type of crown ether cross-linked chitosan was synthesized by the reaction of chitosan with 4,4′-dibromodibenzo-18-crown-6 (Br-DBC). Its token structure was analyzed with FT-IR and NMR and the adsorption behaviors for lead and cadmium in environmental water samples by FAAS were studied. In addition the best analysis conditions were discussed and the adsorption mechanism was explained. As the enrichment factor is above 100, both recoveries are 94%–106%, the detection limits of lead and cadmium are 0.5μg·L?1 and 0.04 μg·L?1 and the relatively standard deviations of lead and cadmium are 3.1% and 2.8% respectively, this new method was successfully applied to the determination of environmental water samples. This method is fast and simple and it greatly enhances the determination ability of FAAS for lead and cadmium.展开更多
In this study, we prepared and applied polymeric porous microsphere adsorbents with selectivity for Li^+ extraction from aqueous solution. We synthesized the adsorbents by suspension polymerization using methacryloyox...In this study, we prepared and applied polymeric porous microsphere adsorbents with selectivity for Li^+ extraction from aqueous solution. We synthesized the adsorbents by suspension polymerization using methacryloyoxyme-12-crown-4(M12C4) as a functional monomer, which had been synthesized from 2-hyroxymethyl-12-crown-4 and methacryloyl chloride. We verified the chemical composition by solid nuclear magnetic resonance(13C-NMR) spectroscopy and observed the porous structure by scanning electron microscopy(SEM). We conducted adsorption isothermal and kinetic tests to determine the adsorption properties. It was found that the adsorbents showed high adsorption efficiency and an adsorption equilibrium time of 200 min. In addition, since the crown ether used in this work could form a stable complex with Li^+, we observed good selectivity for Li^+ in the prepared solution compared with other ions such as Na^+, K^+, Mg^(2+), and Ca^(2+). We reused the adsorbents five times with no significant decrease in adsorptive capacity.展开更多
Electrolyte engineering is considered as an effective strategy to establish stable solid electrolyte interface(SEI),and thus to suppress the growth of lithium dendrites.In a recent study reported in Advanced Functiona...Electrolyte engineering is considered as an effective strategy to establish stable solid electrolyte interface(SEI),and thus to suppress the growth of lithium dendrites.In a recent study reported in Advanced Functional Materials by Ma group,discovered that strong coordination force could be founded between 15-Crown-5 ether(15-C-5) and Li+,which facilitates the crown ether(15-C-1) to participate in the solvation structure of Li+ in the electrolyte for the same purpose.Such a novel strategy might impact the design of highperformance and safe lithium metal batteries(LMB s).展开更多
Five new aza-crown ethers have been prepared by the condensation of 2,6-bis[(2-formylphenyl)oxymethyl] pyridine with different diamino compounds in hot methanol, the bis-Schiff bases without isolation were reduced wit...Five new aza-crown ethers have been prepared by the condensation of 2,6-bis[(2-formylphenyl)oxymethyl] pyridine with different diamino compounds in hot methanol, the bis-Schiff bases without isolation were reduced with NaBH4 to afford the corresponding aza-crown ethers. The liquid membrane transport or alkali cations using the five new macrocycles as the ion-carriers was also studied.展开更多
A new crown ether appended Fe（Ⅲ） porphyrin complex was prepared by sulfuryl chloride appended benzo-15-crown-5 to the meso position of meso-5,10,15,20-tetra（4-hydrophenyl）porphyrin,and it was applied to catalytic...A new crown ether appended Fe（Ⅲ） porphyrin complex was prepared by sulfuryl chloride appended benzo-15-crown-5 to the meso position of meso-5,10,15,20-tetra（4-hydrophenyl）porphyrin,and it was applied to catalytic oxidation of cyclohexene with molecular oxygen without reductant,showing a remarkable catalytic activity（conversion is up to 94%） and selectivity for 2-cyclohexen-1-ol（73%）.展开更多
Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric ...Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.展开更多
13-Crown-4, 16-crown-5, dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields. Irradiation of diols and dichlorides in the presence of sodium hydroxide in ...13-Crown-4, 16-crown-5, dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields. Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect. ？2009 Hossein Eshghi. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.展开更多
A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described.Some of these aryl-incorporated ditosylates reac...A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described.Some of these aryl-incorporated ditosylates reacted with diphenols to produce crown ethers in pleasant yield.展开更多
The influence of crown ether on behaviors of arsenic at different temperatures and residence time was investigated during the pyrolysis of Tuanbo （TB） coal. The modes of occurrence of arsenic were determined by sequ...The influence of crown ether on behaviors of arsenic at different temperatures and residence time was investigated during the pyrolysis of Tuanbo （TB） coal. The modes of occurrence of arsenic were determined by sequential chemical extraction, density fractionation and demineralization. The results indicated that at the same temperature and residence time, the arsenic removal adding dibenzo-18-crown-6 was higher than that adding 18-crown-6, and were all higher than that of TB coal during pyrolysis. When temperature was 850 ℃ and residence time was 30 min, the arsenic removal of TB coal was 30.63%; at the same condition, the arsenic removal while adding 18-crown-6 was 33.21%, higher than that of TB coal; and the arsenic removal while adding dibenzo-18-crown-6 was 67.41%, significantly higher than that of TB coal. From the results, we can see that adding crown ether can improve the arsenic removal during coal pyrolysis, and especially be conducive to the arsenic which is mainly associated with sulfates ＆ monosulfides and that in stable forms.展开更多
Organically modified montmorillonite(OMMT) was incorporated into the complex of 18-crown-6(CE) and polyimide-croum ether(PI[CE]), and its effect on the properties of the complex was evaluated in terms of thermal behav...Organically modified montmorillonite(OMMT) was incorporated into the complex of 18-crown-6(CE) and polyimide-croum ether(PI[CE]), and its effect on the properties of the complex was evaluated in terms of thermal behaviors, coefficient of thermal expansion, mechanical properties, dynamic mechanical properties and water absorption. The results indicate that the overall properties of PI[CE] complex are obviously enhanced. A very low coefficient of thermal expansion of 17.9 ppm/K, a high tensile strength of 124.5 MPa, and toughness of 30.8 MJ/m3 can be achieved for the OMMT/PI[CE] nanocomposite with 3 wt% OMMT. Meanwhile, the thermal stability of the PI[CE] complex is improved, and its 5% weight loss(T_(d5%)) and Tg increase by 10.6 and 23.0 ℃, respectively, and the water absorption rate decreases from 1.73% to 1.13%. The homogeneous dispersion and strong interactions of OMMT with PI[CE] matrix are responsible for the superior properties of the nanocomposites according to SEM and XRD results.展开更多
Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching e...Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching effect between the cavities of crown ethers and Li+,crown ethers can selectively adsorb Li^(+).Herein,1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 was synthesized and used to extract lithium from a Li^(+)/Na^(+)mixed solution.Density functional theory(DFT)was used to explore the properties of complexes with M062X.The results show that the interactions between crown ethers and metal ions are due to electrostatic attraction.Hydroxyl functional groups can synergistically extract Li^(+)/Na^(+)from solutions with the oxygen atom in the crown ether ring.The stability of the complex is also enhanced by van der Waals interactions between the butyrate acid root and crown ether.1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 has a stronger interaction with lithium butyrate than with sodium butyrate for most conformations.The adsorption selectivity for Li+is proportional to the number of ether oxygen atoms that interact with Li^(+).The Li^(+)extraction efficiency increases from 3.93%to 20.93%in lithium hydroxide solution with the presence of butyrate acid root.When the butyrate acid root is added to the mixed Li^(+)/Na^(+)solution,the Li^(+)extraction efficiency increases from 6.54%to 31.20%,while the Li^(+)/Na^(+)separation coefficient decreases from33.25 to 1.32.展开更多
Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous ...Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.展开更多
It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for ...It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.展开更多
The synthesis, characterization of five ditopic or tritopic crown compounds were reported in this paper together with the preparation of the corresponding hetero-dinuclear and hetero-trinuclear complexes with differen...The synthesis, characterization of five ditopic or tritopic crown compounds were reported in this paper together with the preparation of the corresponding hetero-dinuclear and hetero-trinuclear complexes with different metal cations.展开更多
基金supported by the following research grant.The Creative Group Fund of National Natural Science Foundation of China(Grant no.22021005)the Fund of National Natural Science Foundation of China(Grant no.22075037)HEC for National Research Program for Universities(NRPU)Project no.14840.
文摘Anion exchange membrane(AEM)fuel cells require membranes with a balance of high conductivity and durability.In this work,a novel bi-crown-ether modified piperidine structure was designed and synthesized,which was then introduced into the side chain of poly(arylene piperidinium),making a unique bi-crown-ether modified bi-piperidinium side chain grafted polymer for AEM fabrication.The double crown ether units enhanced cation–water interactions and promoted microphase separation,thereby forming efficient hydroxide ion transport channels.The resulting membrane exhibited high water uptake,well-defined ion clusters,and a hydroxide conductivity of 123 mS cm^(-1) at 80℃ with an ion exchange capacity(IEC)of 1.56 mmol g^(-1).After alkaline treatment in 1 M NaOH at 80℃ for 960 h,the membrane retained~85%of its initial conductivity,demonstrating excellent chemical stability.In H2/O2 fuel cell tests at 60℃ ,the membrane achieved a peak power density of 558 mW cm-2 at 1040 mA cm-2.These findings highlight the potential of bi-crown-ether modified piperidinium side chain grafting as an effective strategy to enhance ion conduction properties of AEMs for fuel cell applications.
基金support from the National Natural Science Foundation of China (Grant No.U21B2094 and Grant No.U2067212)。
文摘The separation of lithium isotopes (^(6)Li and ^(7)Li) is of great importance for the nuclear industry.The lithium amalgam method is the only lithium isotopes separation process in industry,and the extensive use of mercury has raised concerns about its potential environmental hazards,which have prompted the search for more efficient and environmentally friendly alternatives.Crown ethers can bind lithium ions highly selectively and separate lithium isotopes effectively.A chemical exchange-based lithium isotopes separation method using crown ether decorated materials could be a viable and cost-effective alternative to the lithium amalgam method.In this review,we provide a systematic summary of the recent advances in lithium isotopes separation using crown ethers decorated materials.
基金financially supported by the National Natural Science Foundation of China (52174336)the Natural Science Foundation of Shandong Province (ZR2021MB051)。
文摘In recent years,with the rapid developme nt of the econo my and society,pollution of valuable metal ions in wastewater has become a major challenge to environmental sustainability.In order to solve the pollution caused by metal ions,researchers have conducted continuous re searches and explored various re mediation methods.Crown ether has attracted great attention because of its ionic radius and cavity size matching well with metal ions,which makes it have the ability to selectively complex metal ions.This unique property enables the directed removal and recovery of metal ions and makes crown ethers increasingly popular in extraction and separation processes.In this paper,the research progress of crown ethers in the extraction and separation of valuable metal ions was reviewed,with emphasis on the principles,extraction systems and the key factors affecting the extraction process.This study can provide some technical support for the application of separation and extraction of valuable metal ions by crown ether.
文摘Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.
基金the National Natural Science Foundation of China （No.20274034）.
文摘A new stable salen Schiff base cobalt and crown ether sodium complex （SalCo-NaB18C6） was prepared through copolymerization. This copolymer complex was applied to catalytic oxidation of hydrocarbon compound with molecular oxygen without reductant, which was shown the higher activity and selectivity for ketone, and reused effectively.
文摘The cross-linking of crown ether-SE-54 in fused-silica capillary columns were initiated by dicumyl peroxide(DCUP),azo-bis-isobutyronitrile (AIBN)and ozone(O_3).Parameters of evaluation such as polarity,selectivity, phase transition temperature and thermal stability were studied and compared with those of poly(crown ether)stationary phase.
文摘A new type of crown ether cross-linked chitosan was synthesized by the reaction of chitosan with 4,4′-dibromodibenzo-18-crown-6 (Br-DBC). Its token structure was analyzed with FT-IR and NMR and the adsorption behaviors for lead and cadmium in environmental water samples by FAAS were studied. In addition the best analysis conditions were discussed and the adsorption mechanism was explained. As the enrichment factor is above 100, both recoveries are 94%–106%, the detection limits of lead and cadmium are 0.5μg·L?1 and 0.04 μg·L?1 and the relatively standard deviations of lead and cadmium are 3.1% and 2.8% respectively, this new method was successfully applied to the determination of environmental water samples. This method is fast and simple and it greatly enhances the determination ability of FAAS for lead and cadmium.
基金supported by Tianjin University-Qinghai Nationalities University Joint Innovation Fund(no.2016XZC-0034)
文摘In this study, we prepared and applied polymeric porous microsphere adsorbents with selectivity for Li^+ extraction from aqueous solution. We synthesized the adsorbents by suspension polymerization using methacryloyoxyme-12-crown-4(M12C4) as a functional monomer, which had been synthesized from 2-hyroxymethyl-12-crown-4 and methacryloyl chloride. We verified the chemical composition by solid nuclear magnetic resonance(13C-NMR) spectroscopy and observed the porous structure by scanning electron microscopy(SEM). We conducted adsorption isothermal and kinetic tests to determine the adsorption properties. It was found that the adsorbents showed high adsorption efficiency and an adsorption equilibrium time of 200 min. In addition, since the crown ether used in this work could form a stable complex with Li^+, we observed good selectivity for Li^+ in the prepared solution compared with other ions such as Na^+, K^+, Mg^(2+), and Ca^(2+). We reused the adsorbents five times with no significant decrease in adsorptive capacity.
文摘Electrolyte engineering is considered as an effective strategy to establish stable solid electrolyte interface(SEI),and thus to suppress the growth of lithium dendrites.In a recent study reported in Advanced Functional Materials by Ma group,discovered that strong coordination force could be founded between 15-Crown-5 ether(15-C-5) and Li+,which facilitates the crown ether(15-C-1) to participate in the solvation structure of Li+ in the electrolyte for the same purpose.Such a novel strategy might impact the design of highperformance and safe lithium metal batteries(LMB s).
基金We are gr ateful to the Natural Sc ience Foundation of Shandong Province for financial support ofthiswork (Q97B03123).
文摘Five new aza-crown ethers have been prepared by the condensation of 2,6-bis[(2-formylphenyl)oxymethyl] pyridine with different diamino compounds in hot methanol, the bis-Schiff bases without isolation were reduced with NaBH4 to afford the corresponding aza-crown ethers. The liquid membrane transport or alkali cations using the five new macrocycles as the ion-carriers was also studied.
基金the National Natural Science Foundation of China(No51063006)the Key Subject Foundation of Tianshui Normal University(NoTSA0818)for providing financial support for this project
文摘A new crown ether appended Fe（Ⅲ） porphyrin complex was prepared by sulfuryl chloride appended benzo-15-crown-5 to the meso position of meso-5,10,15,20-tetra（4-hydrophenyl）porphyrin,and it was applied to catalytic oxidation of cyclohexene with molecular oxygen without reductant,showing a remarkable catalytic activity（conversion is up to 94%） and selectivity for 2-cyclohexen-1-ol（73%）.
基金This project was financially supported by the National Natural Science Foundation of China(Approved No.29775006)
文摘Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.
文摘13-Crown-4, 16-crown-5, dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields. Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect. ？2009 Hossein Eshghi. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.
基金the National Science Foundation(No.DMR0097126)Thanks for good advice from Professor Feihe Huang.
文摘A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described.Some of these aryl-incorporated ditosylates reacted with diphenols to produce crown ethers in pleasant yield.
基金Supported by the Research Fund for the Doctoral Program of Higher Education of China for New Teachers （20091404120002） the Shanxi Provincial Science Foundation for Youths of China （2011021008-1）
文摘The influence of crown ether on behaviors of arsenic at different temperatures and residence time was investigated during the pyrolysis of Tuanbo （TB） coal. The modes of occurrence of arsenic were determined by sequential chemical extraction, density fractionation and demineralization. The results indicated that at the same temperature and residence time, the arsenic removal adding dibenzo-18-crown-6 was higher than that adding 18-crown-6, and were all higher than that of TB coal during pyrolysis. When temperature was 850 ℃ and residence time was 30 min, the arsenic removal of TB coal was 30.63%; at the same condition, the arsenic removal while adding 18-crown-6 was 33.21%, higher than that of TB coal; and the arsenic removal while adding dibenzo-18-crown-6 was 67.41%, significantly higher than that of TB coal. From the results, we can see that adding crown ether can improve the arsenic removal during coal pyrolysis, and especially be conducive to the arsenic which is mainly associated with sulfates ＆ monosulfides and that in stable forms.
基金Funded by the National Natural Science Foundation of China(51573054)the Project for Science and Technology of Guangdong Province(2014B090916001)
文摘Organically modified montmorillonite(OMMT) was incorporated into the complex of 18-crown-6(CE) and polyimide-croum ether(PI[CE]), and its effect on the properties of the complex was evaluated in terms of thermal behaviors, coefficient of thermal expansion, mechanical properties, dynamic mechanical properties and water absorption. The results indicate that the overall properties of PI[CE] complex are obviously enhanced. A very low coefficient of thermal expansion of 17.9 ppm/K, a high tensile strength of 124.5 MPa, and toughness of 30.8 MJ/m3 can be achieved for the OMMT/PI[CE] nanocomposite with 3 wt% OMMT. Meanwhile, the thermal stability of the PI[CE] complex is improved, and its 5% weight loss(T_(d5%)) and Tg increase by 10.6 and 23.0 ℃, respectively, and the water absorption rate decreases from 1.73% to 1.13%. The homogeneous dispersion and strong interactions of OMMT with PI[CE] matrix are responsible for the superior properties of the nanocomposites according to SEM and XRD results.
基金financially supported by the National Natural Science Foundation of China(Nos.51704011,U1703130 and 51904003)。
文摘Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching effect between the cavities of crown ethers and Li+,crown ethers can selectively adsorb Li^(+).Herein,1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 was synthesized and used to extract lithium from a Li^(+)/Na^(+)mixed solution.Density functional theory(DFT)was used to explore the properties of complexes with M062X.The results show that the interactions between crown ethers and metal ions are due to electrostatic attraction.Hydroxyl functional groups can synergistically extract Li^(+)/Na^(+)from solutions with the oxygen atom in the crown ether ring.The stability of the complex is also enhanced by van der Waals interactions between the butyrate acid root and crown ether.1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 has a stronger interaction with lithium butyrate than with sodium butyrate for most conformations.The adsorption selectivity for Li+is proportional to the number of ether oxygen atoms that interact with Li^(+).The Li^(+)extraction efficiency increases from 3.93%to 20.93%in lithium hydroxide solution with the presence of butyrate acid root.When the butyrate acid root is added to the mixed Li^(+)/Na^(+)solution,the Li^(+)extraction efficiency increases from 6.54%to 31.20%,while the Li^(+)/Na^(+)separation coefficient decreases from33.25 to 1.32.
基金supported by the National Natural Science Foundation of China(U21A20332,52103226,52202275,52203314,and 12204253)the Distinguished Young Scholars Fund of Jiangsu Province(BK20220061)the Fellowship of China Postdoctoral Science Foundation(2021M702382)。
文摘Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.
基金supported by the National Natural Science Foundation of China(No.51604005,No.U1703130,and No.51574003)
文摘It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.
基金the National Natural Science Foundation of China (29872034) and the Natural Science Foundation of Henan Province for the financi
文摘The synthesis, characterization of five ditopic or tritopic crown compounds were reported in this paper together with the preparation of the corresponding hetero-dinuclear and hetero-trinuclear complexes with different metal cations.
