The copolymer poly（3-（4-fluorophenyl）thiophene-co-3-methylthiophene） was successfully prepared from mixtures of 3-（4-fluorophenyl）thiophene （FPT） and 3-methylthiophene （MET） via electrochemical oxidation in ...The copolymer poly（3-（4-fluorophenyl）thiophene-co-3-methylthiophene） was successfully prepared from mixtures of 3-（4-fluorophenyl）thiophene （FPT） and 3-methylthiophene （MET） via electrochemical oxidation in boron trifluoride diethyl etherate （BFEE） and its mixed electrolytes with acetonitrile （ACN）. The influence of monomer concentration ratios on the copolymerization was investigated by using linear sweep voltammetry and cyclic voltammetry. The structure and morphology of these copolymer films were elucidated by UV-Vis, infrared spectroscopy, elemental analysis, thermal analysis and scanning electron microscopy （SEM）, respectively. The results showed that the molar ratio of FPT and MeT units, when copolymer was electrodeposited from feed ratio of FPT：MeT = 1：2, was about 1.08：1. In addition, the introduction of ACN into BFEE has little effect on the properties of as-formed copolymers.展开更多
The copolymerization of dibenzofuran(DBF)and 3-methylthiophene(MET)was successfully achieved electrochemically by direct anodic oxidation of the monomer mixtures in boron trifluoride diethyl etherate.The effects of ap...The copolymerization of dibenzofuran(DBF)and 3-methylthiophene(MET)was successfully achieved electrochemically by direct anodic oxidation of the monomer mixtures in boron trifluoride diethyl etherate.The effects of applied polymerization potential and the monomer concentration ratios on the copolymerization were investigated by linear sweep voltammetry and cyclic voltammetry(CV).The structure of copolymer films were investigated by UV-Vis,infrared spectroscopy,thermal analysis.As-formed novel copolymers own...展开更多
High quality poly（5-cyanoindole） （P5CI） films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate （BFEE） a...High quality poly（5-cyanoindole） （P5CI） films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate （BFEE） and diethyl ether （EE） （by volume 1：1） ＋ 0,05 mol L^-1 Bu4NBF4. The film formed can be peeled off the electrode into freestanding films, The addition of EE into BFEE can improve the solubility of monomer. P5CI films obtained from this medium showed excellent electrochemical behavior with conductivity of 10^-2 S cm^-1, Structural studies showed that the polymerization of 5-cyanoindole occurred at the 2,3 position. As-formed P5CI films were thoroughly soluble in strong polar organic solvent dimethyl sulfoxide （DMSO） while partly soluble in tetrahydrofuran （THF） or acetone. Fluorescence spectral studies indicated that P5CI was a good blue-ight emitter.展开更多
?-Phenyl－4－aroylfuran－3－carboxylic acids were reduced in aqueous alkaline solutions ofNaBH4 to afford hydroxy acids in excellent yields． Under the catalysis of boron trifluoride etherate，the hydroxy acids were c...?-Phenyl－4－aroylfuran－3－carboxylic acids were reduced in aqueous alkaline solutions ofNaBH4 to afford hydroxy acids in excellent yields． Under the catalysis of boron trifluoride etherate，the hydroxy acids were converted to lactones smoothly．展开更多
Regioselective addition reactions of silyl enolates to a, b-unsaturated aldehyde and its acetal catalyzed by MgI2 etherate give aldol adducts (1, 2-addition) preferentially over Michael adducts (1, 4-addition). This ...Regioselective addition reactions of silyl enolates to a, b-unsaturated aldehyde and its acetal catalyzed by MgI2 etherate give aldol adducts (1, 2-addition) preferentially over Michael adducts (1, 4-addition). This unique regioselectivity is distinctly different with other Lewis acidic promoters and may be attributed to the high oxyphilicity of IMg+.展开更多
Direct aldol condensation of various aromatic, heteroaromatic, α,β-unsaturated aldehydes and aliphatic aldehydes with acyldiazomethane was realized using Mgl2 etherate （Mgl2.（Et2O）n） as a promoter in the presenc...Direct aldol condensation of various aromatic, heteroaromatic, α,β-unsaturated aldehydes and aliphatic aldehydes with acyldiazomethane was realized using Mgl2 etherate （Mgl2.（Et2O）n） as a promoter in the presence of diisopropyl amine （DIPEA） in excellent yields in a short time under mild conditions with high chemoselectivity. Iodide counterion, and a non-coordinating less ploar reaction media （i.e., CH2C12） are among the critical factors for this unique reactivity.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
Asplactones A-E(1-5),five unique diphenyl ether hybrids,along with two rare spiro-diphenyl ethers,aspviolaceols A(6)and B(7),were isolated and characterized from Aspergillus sp.F1-8A,an endophytic fungus associated wi...Asplactones A-E(1-5),five unique diphenyl ether hybrids,along with two rare spiro-diphenyl ethers,aspviolaceols A(6)and B(7),were isolated and characterized from Aspergillus sp.F1-8A,an endophytic fungus associated with the parotoid glands of Bufo gargarizans Cantor.Compounds 1-5 represent the first examples of diphenyl ether hybrids fused with unusual moieties,including conjugatedγ-butyrolactone and cyclopentenone.Compounds 6 and 7 are the first known natural spiro-diphenyl ethers,with 6 featuring an uncommon 6/6/6/6-membered carbon skeleton,and 7 possessing a distinct 6/6/6/6/6/6-membered diphenyl ether spiro-heterodimer carbon framework.Structural elucidation was performed using a combination of spectroscopic techniques,X-ray crystallography,and quantum-chemical calculations,and plausible biosynthetic pathways were proposed.Biologically,compounds 1,2,4,6,and 7 exhibited antioxidant activity comparable to or surpassing that of vitamin C in 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)(ABTS),and ferric reducing power assays.They also significantly improved cell viability in H2O2-induced oxidative injury assays using A549 cells.展开更多
Although human milk fat substitute(HMFS)has been wildly applied in infant formula(IF),there are still some differences in fat composition between human milk and IF,which is extremely attributed to the phospholipid com...Although human milk fat substitute(HMFS)has been wildly applied in infant formula(IF),there are still some differences in fat composition between human milk and IF,which is extremely attributed to the phospholipid composition.We therefore designed a human milk phospholipid substitute(HMPS),and investigated its nutritional outcomes on brain development using C57BL/6J mice.Results showed that HMPS improved mice's cognitive behavior and dendritic development compared to soybean phospholipids and nophospholipid diets.Based on the lipidomics,we revealed that these beneficial outcomes were potentially associated with the increased biosynthesis of N-acylethanolamines,phosphatidylethanolamine(PE),and ether PE,and the decreased metabolism of diacylglycerol and hexosylceramide in brain.It was further found in Kyoto Encyclopedia of Genes and Genomes analysis that glycerophospholipid metabolic pathway participated in the improvement of HMPS on mice's neurodevelopment.In conclusion,this study demonstrated that HMPS improves mice's neurodevelopment,and the glycerophospholipid metabolic pathway plays a major role in this beneficial result,and provided evidence for future application of HMPS in commercial IF.展开更多
Polybrominated biphenyl ethers(PBDEs)and polycyclic aromatic hydrocarbons(PAHs)are commonly detected contaminants at e-waste recycling sites.Against the conventional wisdom that PBDEs and PAHs are highly immobile and ...Polybrominated biphenyl ethers(PBDEs)and polycyclic aromatic hydrocarbons(PAHs)are commonly detected contaminants at e-waste recycling sites.Against the conventional wisdom that PBDEs and PAHs are highly immobile and persist primarily in shallowsurface soils,increasing evidence shows that these compounds can leach into the groundwater.Herein,we compare the leachabilities of PBDEs vs.PAHs from contaminated soils collected at an e-waste recycling site in Tianjin,China.Considerable amounts of BDE-209(0.3–2 ng/L)and phenanthrene(42–106 ng/L),the most abundant PBDE and PAH at the site,are detected in the effluents of columns packed with contaminated soils,with the specific concentrations varying with hydrodynamic and solution chemistry conditions.Interestingly,the leaching potential of BDE-209 appears to be closely related to the release of colloidal mineral particles,whereas the leachability of phenanthrene correlates well with the concentration of dissolved organic carbon in the effluent,but showing essentially no correlation with the concentration of mineral particles.The surprisingly different trends of the leachability observed between BDE-209 and phenanthrene is counterintuitive,as PBDEs and PAHs often co-exist at e-waste recycling sites(particularly at the sites wherein incineration is being practiced)and share many similarities in terms of physicochemical properties.One possible explanation is that due to its extremely low solubility,BDE-209 predominantly exists in free-phase(i.e.,as solid(nano)particles),whereas the more soluble phenanthrene is mainly sorbed to soil organic matter.Findings in this study underscore the need to better understand the mobility of highly hydrophobic organic contaminants at contaminated sites for improved risk management.展开更多
Polybromodiphenyl ethers(PBDEs),the widely used flame retardants,are common contaminants in surface soils at e-waste recycling sites.The association of PBDEs with soil colloids has been observed,indicating the potenti...Polybromodiphenyl ethers(PBDEs),the widely used flame retardants,are common contaminants in surface soils at e-waste recycling sites.The association of PBDEs with soil colloids has been observed,indicating the potential risk to groundwater due to colloid-facilitated transport.However,the extent to which soil colloidsmay enhance the spreading of PBDEs in groundwater is largely unknown.Herein,we report the co-transport of decabromodiphenyl ester(BDE-209)and soil colloids in saturated porous media.The colloids released froma soil sample collected at an e-waste recycling site in Tianjin,China,contain high concentration of PBDEs,with BDE-209 being the most abundant conger(320±30 mg/kg).The colloids exhibit relatively high mobility in saturated sand columns,under conditions commonly observed in groundwater environments.Notably,under all the tested conditions(i.e.,varying flow velocity,pH,ionic species and ionic strength),the mass of eluted BDE-209 correlates linearly with that of eluted soil colloids,even though the mobility of the colloids varies markedly depending on the specific hydrodynamic and solution chemistry conditions involved.Additionally,the mass of BDE-209 retained in the columns also correlates strongly with themass of retained colloids.Apparently,the PBDEs remain bound to soil colloids during transport in porous media.Findings in this study indicate that soil colloidsmay significantly promote the transport of PBDEs in groundwater by serving as an effective carrier.This might be the reason why the highly insoluble and adsorptive PBDEs are found in groundwater at some PBDE-contaminated sites.展开更多
A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones w...A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.展开更多
The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques inc...The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques including XRD,XPS,N2O titration,and 27Al MAS-NMR.The results showed that when the crystal configurations of Al_(2)O_(3) were the same,increasing the specific surface area could effectively refine the size of copper nanoparticles(Cu NPs),and ultimately improve the conversion of DEO.Meanwhile,the smaller size ofγ-Al_(2)O_(3)(HSAl and SBAl)loaded Cu NPs promotes the reaction towards the deep hydrogenation to produce ethanol(EtOH)and ethylene glycol(EG).Besides,the larger size of Cu NPs on the surface of amorphous Al_(2)O_(3)(HTAl and SolAl)resulted in a lower conversion rate,where ethyl glycolate(Egly)is the main product.Despite there are differences in Al^(3+)ionic coordination in Al_(2)O_(3) with different crystal structures,the experimental data showed that the differences in Al^(3+)ionic coordination did not significantly affect the catalytic performance in the hydrogenation reaction.The formation of alcohol-ether ester chemicals is critically dependent on the interactions between Cu sites and acidic sites.Among them,EG and EtOH were dehydrated to form 2-ethoxyethanol via the SN2 mechanism,while Egly and EtOH were reacted to form ethyl ethoxyacetate(EEA)via the SN2 mechanism.This study provides a theoretical basis for the optimization of the coal-based glycol processes to achieve a diversified product portfolio.展开更多
The ring has been a romantic fascination throughout the ages,embodying not only beauty and order but also harboring numerous undisclosed properties awaiting discovery.In the realm of supramolecular chemistry,macrocycl...The ring has been a romantic fascination throughout the ages,embodying not only beauty and order but also harboring numerous undisclosed properties awaiting discovery.In the realm of supramolecular chemistry,macrocycles,with a cyclic structure and a central cavity like a doughnut,captivate the attention of scientists[1].In 1967,Pedersen's groundbreaking revelation that alkali metal ions could"fall into"the cavities of a cyclic ether named crown ether,even in organic solvents,unveiled a novel universe of macrocycle chemistry.Since then,numerous macrocyclic structures in nature have been discovered,isolated,and scrutinized.Drawing inspiration from nature,chemists endeavor to explore the vast potential of macrocyclic compounds by designing and synthesizing artificial macrocycles with diverse structural features and recognition properties.展开更多
Trehalase hydrolyzes trehalose to glucose to provide energy for insects or building blocks for chitin synthesis.Because trehalase is critical to insects but not to humans,it has long been considered a promising target...Trehalase hydrolyzes trehalose to glucose to provide energy for insects or building blocks for chitin synthesis.Because trehalase is critical to insects but not to humans,it has long been considered a promising target for green insecticides.However,the known trehalase inhibitors are mainly sugar derivatives with poor druggability.In this study,the trehalase from Ostrinia furnacalis(OfTreh)was expressed and characterized.By integrative computational strategies,diphenyl ether herbicides were discovered as the first non-carbohydrate inhibitors of insect trehalases.Bifenox and its more stable derivative,chlomethoxyfen,inhibited Of Treh with Ki values of 56 and 43μM,respectively.The oral administration of bifenox or chlomethoxyfen to locusts resulted in the inhibition of trehalose hydrolysis in vivo,leading to a mortality rate of 66%and server locomotion disorder in the survivors.This study not only established a platform for the development of insecticides targeting trehalase but also discovered a new mechanism for diphenyl ethers to kill insects as trehalase inhibitors.展开更多
The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of ...The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of dimethyl ether(DME),which is derived from fossil resources,represents a promising approach to producing high-concentration formaldehyde with low energy consumption.However,there is still a lack of catalysts achieving satisfactory conversion of DME with high selectivity for formaldehyde under mild conditions.In this work,an efficient iron-molybdate(FeMo)catalyst was developed for the selective oxidation of DME to formaldehyde.The DME conversion of 84% was achieved with a superior formaldehyde selectivity(77%)at 300℃,a performance that is superior to all previously reported results.In an approximately 550 h continuous reaction,the catalyst maintained a conversion of 64% and a formaldehyde selectivity of 79%.Combined X-ray diffraction(XRD),Transmission electron microscope(TEM),Ultraviolet-visible spectroscopy(UV-Vis),Hydrogen temperature-programmed reduction(H_(2)-TPR),Fourier transform infrared(FT-IR)analyses,along with density functional theory(DFT)calculations,demonstrated that the excellent FeMo catalyst was composed of active Fe_(2)(MoO_(4))_(3)and MoO_(3)phases,and there was an interaction between them,which contributed to the efficient DME dissociation and smooth hydrogen spillover,leading to a superior DME conversion.With the support of DME/O_(2)pulse experiments,in-situ Raman,in-situ Dimethyl ether infrared spectroscopy(DME-IR)and DFT calculation results,a Mars-van Krevelen(MvK)reaction mechanism was proposed:DME was dissociated on the interface between Fe_(2)(MoO_(4))_(3)and MoO_(3)phases to form active methoxy species firstly,and it dehydrogenated to give hydrogen species;the generated hydrogen species smoothly spilled over from Fe_(2)(MoO_(4))_(3)to MoO_(3)enhanced by the interaction between Fe_(2)(MoO_(4))_(3)and MoO_(3);then the hydrogen species was consumed by MoO_(3),leading to a reduction of MoO_(3),and finally,the reduced MoO_(3)was re-oxidized by O_(2),returning to the initial state.These findings offer valuable insights not only for the development of efficient FeMo catalysts but also for elucidating the reaction mechanism involved in the oxidation of DME to formaldehyde,contributing to the optimized utilization of DME derived from fossil resources.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
Hydrogel electrolytes based on natural polymers have attracted increasing attention in zinc-ion batteries(ZIBs)powering wearable and implantable electronics,but designing natural polymer hydrogels with high ionic cond...Hydrogel electrolytes based on natural polymers have attracted increasing attention in zinc-ion batteries(ZIBs)powering wearable and implantable electronics,but designing natural polymer hydrogels with high ionic conductivity,excellent transference performance,and inhibited Zn dendrites is still challenging.Herein,two natural biocompatible polymers(sodium alginate(SA)and agarose(AG))are used to prepare composite hydrogel electrolytes ensuring electrostatic interaction between–COO–groups in SA and Zn^(2+)and coordination between C–O–C groups in AG and Zn^(2+).The as-obtained hydrogels exhibit an elevated ionic conductivity(25.05 mS cm^(−1))with a high transference number(0.75),useful for facilitated efficient Zn^(2+)transport.The theoretical calculations combined with experimental results reveal C–O–C groups endowing the as-prepared hydrogels with improved desolvation kinetics and capture ability of Zn^(2+)for achieving dendrite-free Zn deposition.In this way,the assembled Zn symmetric cell shows a long cycle life reaching 700 h at 0.2 mA cm^(−2).The exceptional biocompatibility of the hydrogels also results in cell viability assay with a survival rate above 93.5%.Overall,the proposed hydrogel electrolytes endow solid-state ZIBs with high discharge capacity,outstanding rate performance,long cycle life,good antifreeze capability,and impressive flexibility,useful features for future design and development of advanced ZIBs.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No. 20564001)the Natural Science Foundation of Jiangxi Province (No. 050017)
文摘The copolymer poly（3-（4-fluorophenyl）thiophene-co-3-methylthiophene） was successfully prepared from mixtures of 3-（4-fluorophenyl）thiophene （FPT） and 3-methylthiophene （MET） via electrochemical oxidation in boron trifluoride diethyl etherate （BFEE） and its mixed electrolytes with acetonitrile （ACN）. The influence of monomer concentration ratios on the copolymerization was investigated by using linear sweep voltammetry and cyclic voltammetry. The structure and morphology of these copolymer films were elucidated by UV-Vis, infrared spectroscopy, elemental analysis, thermal analysis and scanning electron microscopy （SEM）, respectively. The results showed that the molar ratio of FPT and MeT units, when copolymer was electrodeposited from feed ratio of FPT：MeT = 1：2, was about 1.08：1. In addition, the introduction of ACN into BFEE has little effect on the properties of as-formed copolymers.
基金This work was financially supported by the Natural Science Foundation of China(Nos.50663001,20564001)Ministry of Education(No.2007-207058).
文摘The copolymerization of dibenzofuran(DBF)and 3-methylthiophene(MET)was successfully achieved electrochemically by direct anodic oxidation of the monomer mixtures in boron trifluoride diethyl etherate.The effects of applied polymerization potential and the monomer concentration ratios on the copolymerization were investigated by linear sweep voltammetry and cyclic voltammetry(CV).The structure of copolymer films were investigated by UV-Vis,infrared spectroscopy,thermal analysis.As-formed novel copolymers own...
基金This work was supported by the Jiangxi Research Center for Material Science & Engineering(No.ZX200401008)the Jiangxi Science and Technology Normal University.
文摘High quality poly（5-cyanoindole） （P5CI） films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate （BFEE） and diethyl ether （EE） （by volume 1：1） ＋ 0,05 mol L^-1 Bu4NBF4. The film formed can be peeled off the electrode into freestanding films, The addition of EE into BFEE can improve the solubility of monomer. P5CI films obtained from this medium showed excellent electrochemical behavior with conductivity of 10^-2 S cm^-1, Structural studies showed that the polymerization of 5-cyanoindole occurred at the 2,3 position. As-formed P5CI films were thoroughly soluble in strong polar organic solvent dimethyl sulfoxide （DMSO） while partly soluble in tetrahydrofuran （THF） or acetone. Fluorescence spectral studies indicated that P5CI was a good blue-ight emitter.
文摘?-Phenyl－4－aroylfuran－3－carboxylic acids were reduced in aqueous alkaline solutions ofNaBH4 to afford hydroxy acids in excellent yields． Under the catalysis of boron trifluoride etherate，the hydroxy acids were converted to lactones smoothly．
基金We are grateful for the financial supports from the National Outstanding Youth Fund No.29925204)the Foundation for University Key Teacher by the Ministry of Education of Chinaa Visiting Fund of the National Laboratory of Applied Organic Chemistry.
文摘Regioselective addition reactions of silyl enolates to a, b-unsaturated aldehyde and its acetal catalyzed by MgI2 etherate give aldol adducts (1, 2-addition) preferentially over Michael adducts (1, 4-addition). This unique regioselectivity is distinctly different with other Lewis acidic promoters and may be attributed to the high oxyphilicity of IMg+.
基金the National Natural Science Foundation of China (Nos. 21372203 and 21272076)for the financial support
文摘Direct aldol condensation of various aromatic, heteroaromatic, α,β-unsaturated aldehydes and aliphatic aldehydes with acyldiazomethane was realized using Mgl2 etherate （Mgl2.（Et2O）n） as a promoter in the presence of diisopropyl amine （DIPEA） in excellent yields in a short time under mild conditions with high chemoselectivity. Iodide counterion, and a non-coordinating less ploar reaction media （i.e., CH2C12） are among the critical factors for this unique reactivity.
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supported by the National Natural Science Foundation of China(No.82073721)Major Basic Research Project of the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.23KJA310003).
文摘Asplactones A-E(1-5),five unique diphenyl ether hybrids,along with two rare spiro-diphenyl ethers,aspviolaceols A(6)and B(7),were isolated and characterized from Aspergillus sp.F1-8A,an endophytic fungus associated with the parotoid glands of Bufo gargarizans Cantor.Compounds 1-5 represent the first examples of diphenyl ether hybrids fused with unusual moieties,including conjugatedγ-butyrolactone and cyclopentenone.Compounds 6 and 7 are the first known natural spiro-diphenyl ethers,with 6 featuring an uncommon 6/6/6/6-membered carbon skeleton,and 7 possessing a distinct 6/6/6/6/6/6-membered diphenyl ether spiro-heterodimer carbon framework.Structural elucidation was performed using a combination of spectroscopic techniques,X-ray crystallography,and quantum-chemical calculations,and plausible biosynthetic pathways were proposed.Biologically,compounds 1,2,4,6,and 7 exhibited antioxidant activity comparable to or surpassing that of vitamin C in 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)(ABTS),and ferric reducing power assays.They also significantly improved cell viability in H2O2-induced oxidative injury assays using A549 cells.
基金supported by Huhhot Science&Technology Plan(2021-National Center of Technology innovation for Dairy-4)Innovation Consortium Project(2023RC Consortium-7)+3 种基金National Key Research and Development Program(2023YFF1104502)Ganpo Juncai supports the plan(20232BCJ22046)Nanchang University Jiangxi Financial Science and Technology Special Project(ZBG20230418011)Free Exploration Project of State Key Laboratory(SKLF-ZZB-202317).
文摘Although human milk fat substitute(HMFS)has been wildly applied in infant formula(IF),there are still some differences in fat composition between human milk and IF,which is extremely attributed to the phospholipid composition.We therefore designed a human milk phospholipid substitute(HMPS),and investigated its nutritional outcomes on brain development using C57BL/6J mice.Results showed that HMPS improved mice's cognitive behavior and dendritic development compared to soybean phospholipids and nophospholipid diets.Based on the lipidomics,we revealed that these beneficial outcomes were potentially associated with the increased biosynthesis of N-acylethanolamines,phosphatidylethanolamine(PE),and ether PE,and the decreased metabolism of diacylglycerol and hexosylceramide in brain.It was further found in Kyoto Encyclopedia of Genes and Genomes analysis that glycerophospholipid metabolic pathway participated in the improvement of HMPS on mice's neurodevelopment.In conclusion,this study demonstrated that HMPS improves mice's neurodevelopment,and the glycerophospholipid metabolic pathway plays a major role in this beneficial result,and provided evidence for future application of HMPS in commercial IF.
基金supported by the National Key Research and Development Program of China(No.2019YFC1804202)the National Natural Science Foundation of China(Nos.22020102004 and 22125603)+1 种基金Tianjin Municipal Science and Technology Bureau(No.21JCZDJC00280)the Fundamental Research Funds for the Central Universities,and the Ministry of Education of China(No.T2017002).
文摘Polybrominated biphenyl ethers(PBDEs)and polycyclic aromatic hydrocarbons(PAHs)are commonly detected contaminants at e-waste recycling sites.Against the conventional wisdom that PBDEs and PAHs are highly immobile and persist primarily in shallowsurface soils,increasing evidence shows that these compounds can leach into the groundwater.Herein,we compare the leachabilities of PBDEs vs.PAHs from contaminated soils collected at an e-waste recycling site in Tianjin,China.Considerable amounts of BDE-209(0.3–2 ng/L)and phenanthrene(42–106 ng/L),the most abundant PBDE and PAH at the site,are detected in the effluents of columns packed with contaminated soils,with the specific concentrations varying with hydrodynamic and solution chemistry conditions.Interestingly,the leaching potential of BDE-209 appears to be closely related to the release of colloidal mineral particles,whereas the leachability of phenanthrene correlates well with the concentration of dissolved organic carbon in the effluent,but showing essentially no correlation with the concentration of mineral particles.The surprisingly different trends of the leachability observed between BDE-209 and phenanthrene is counterintuitive,as PBDEs and PAHs often co-exist at e-waste recycling sites(particularly at the sites wherein incineration is being practiced)and share many similarities in terms of physicochemical properties.One possible explanation is that due to its extremely low solubility,BDE-209 predominantly exists in free-phase(i.e.,as solid(nano)particles),whereas the more soluble phenanthrene is mainly sorbed to soil organic matter.Findings in this study underscore the need to better understand the mobility of highly hydrophobic organic contaminants at contaminated sites for improved risk management.
基金supported by the National Key Research and Development Program of China(No.2019YFC1804202)the National Natural Science Foundation of China(No.22020102004)+1 种基金the Tianjin Municipal Science and Technology Bureau(No.21JCZDJC00280)the Fundamental Research Funds for the Central Universities by the Ministry of Education of China(No.T2017002).
文摘Polybromodiphenyl ethers(PBDEs),the widely used flame retardants,are common contaminants in surface soils at e-waste recycling sites.The association of PBDEs with soil colloids has been observed,indicating the potential risk to groundwater due to colloid-facilitated transport.However,the extent to which soil colloidsmay enhance the spreading of PBDEs in groundwater is largely unknown.Herein,we report the co-transport of decabromodiphenyl ester(BDE-209)and soil colloids in saturated porous media.The colloids released froma soil sample collected at an e-waste recycling site in Tianjin,China,contain high concentration of PBDEs,with BDE-209 being the most abundant conger(320±30 mg/kg).The colloids exhibit relatively high mobility in saturated sand columns,under conditions commonly observed in groundwater environments.Notably,under all the tested conditions(i.e.,varying flow velocity,pH,ionic species and ionic strength),the mass of eluted BDE-209 correlates linearly with that of eluted soil colloids,even though the mobility of the colloids varies markedly depending on the specific hydrodynamic and solution chemistry conditions involved.Additionally,the mass of BDE-209 retained in the columns also correlates strongly with themass of retained colloids.Apparently,the PBDEs remain bound to soil colloids during transport in porous media.Findings in this study indicate that soil colloidsmay significantly promote the transport of PBDEs in groundwater by serving as an effective carrier.This might be the reason why the highly insoluble and adsorptive PBDEs are found in groundwater at some PBDE-contaminated sites.
文摘A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.
文摘The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques including XRD,XPS,N2O titration,and 27Al MAS-NMR.The results showed that when the crystal configurations of Al_(2)O_(3) were the same,increasing the specific surface area could effectively refine the size of copper nanoparticles(Cu NPs),and ultimately improve the conversion of DEO.Meanwhile,the smaller size ofγ-Al_(2)O_(3)(HSAl and SBAl)loaded Cu NPs promotes the reaction towards the deep hydrogenation to produce ethanol(EtOH)and ethylene glycol(EG).Besides,the larger size of Cu NPs on the surface of amorphous Al_(2)O_(3)(HTAl and SolAl)resulted in a lower conversion rate,where ethyl glycolate(Egly)is the main product.Despite there are differences in Al^(3+)ionic coordination in Al_(2)O_(3) with different crystal structures,the experimental data showed that the differences in Al^(3+)ionic coordination did not significantly affect the catalytic performance in the hydrogenation reaction.The formation of alcohol-ether ester chemicals is critically dependent on the interactions between Cu sites and acidic sites.Among them,EG and EtOH were dehydrated to form 2-ethoxyethanol via the SN2 mechanism,while Egly and EtOH were reacted to form ethyl ethoxyacetate(EEA)via the SN2 mechanism.This study provides a theoretical basis for the optimization of the coal-based glycol processes to achieve a diversified product portfolio.
文摘The ring has been a romantic fascination throughout the ages,embodying not only beauty and order but also harboring numerous undisclosed properties awaiting discovery.In the realm of supramolecular chemistry,macrocycles,with a cyclic structure and a central cavity like a doughnut,captivate the attention of scientists[1].In 1967,Pedersen's groundbreaking revelation that alkali metal ions could"fall into"the cavities of a cyclic ether named crown ether,even in organic solvents,unveiled a novel universe of macrocycle chemistry.Since then,numerous macrocyclic structures in nature have been discovered,isolated,and scrutinized.Drawing inspiration from nature,chemists endeavor to explore the vast potential of macrocyclic compounds by designing and synthesizing artificial macrocycles with diverse structural features and recognition properties.
基金the staff of the BL18U/BL19U1 Beamline of the National Facility for Protein Science,Shanghai,at the Shanghai Synchrotron Radiation Facility for assistance during data collectionthe National Key Research and Development Program of China(Grant No.2023YFD1700500,2022YFD1700200)the Project of Natural Science Foundation of Liaoning Province(2022-KF-15-02).
文摘Trehalase hydrolyzes trehalose to glucose to provide energy for insects or building blocks for chitin synthesis.Because trehalase is critical to insects but not to humans,it has long been considered a promising target for green insecticides.However,the known trehalase inhibitors are mainly sugar derivatives with poor druggability.In this study,the trehalase from Ostrinia furnacalis(OfTreh)was expressed and characterized.By integrative computational strategies,diphenyl ether herbicides were discovered as the first non-carbohydrate inhibitors of insect trehalases.Bifenox and its more stable derivative,chlomethoxyfen,inhibited Of Treh with Ki values of 56 and 43μM,respectively.The oral administration of bifenox or chlomethoxyfen to locusts resulted in the inhibition of trehalose hydrolysis in vivo,leading to a mortality rate of 66%and server locomotion disorder in the survivors.This study not only established a platform for the development of insecticides targeting trehalase but also discovered a new mechanism for diphenyl ethers to kill insects as trehalase inhibitors.
基金supported by the National Natural Science Foundation of China(U23A2088,22025206)the Dalian Innovation Support Plan for High Level Talents(2022RG13)+2 种基金DICP(Grant:DICP I202453,DICP I202234)the Fundamental Research Funds for the Central Universities(20720220008)support of the Liaoning Key Laboratory of Biomass Conversion for Energy and Material。
文摘The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of dimethyl ether(DME),which is derived from fossil resources,represents a promising approach to producing high-concentration formaldehyde with low energy consumption.However,there is still a lack of catalysts achieving satisfactory conversion of DME with high selectivity for formaldehyde under mild conditions.In this work,an efficient iron-molybdate(FeMo)catalyst was developed for the selective oxidation of DME to formaldehyde.The DME conversion of 84% was achieved with a superior formaldehyde selectivity(77%)at 300℃,a performance that is superior to all previously reported results.In an approximately 550 h continuous reaction,the catalyst maintained a conversion of 64% and a formaldehyde selectivity of 79%.Combined X-ray diffraction(XRD),Transmission electron microscope(TEM),Ultraviolet-visible spectroscopy(UV-Vis),Hydrogen temperature-programmed reduction(H_(2)-TPR),Fourier transform infrared(FT-IR)analyses,along with density functional theory(DFT)calculations,demonstrated that the excellent FeMo catalyst was composed of active Fe_(2)(MoO_(4))_(3)and MoO_(3)phases,and there was an interaction between them,which contributed to the efficient DME dissociation and smooth hydrogen spillover,leading to a superior DME conversion.With the support of DME/O_(2)pulse experiments,in-situ Raman,in-situ Dimethyl ether infrared spectroscopy(DME-IR)and DFT calculation results,a Mars-van Krevelen(MvK)reaction mechanism was proposed:DME was dissociated on the interface between Fe_(2)(MoO_(4))_(3)and MoO_(3)phases to form active methoxy species firstly,and it dehydrogenated to give hydrogen species;the generated hydrogen species smoothly spilled over from Fe_(2)(MoO_(4))_(3)to MoO_(3)enhanced by the interaction between Fe_(2)(MoO_(4))_(3)and MoO_(3);then the hydrogen species was consumed by MoO_(3),leading to a reduction of MoO_(3),and finally,the reduced MoO_(3)was re-oxidized by O_(2),returning to the initial state.These findings offer valuable insights not only for the development of efficient FeMo catalysts but also for elucidating the reaction mechanism involved in the oxidation of DME to formaldehyde,contributing to the optimized utilization of DME derived from fossil resources.
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(no.62101605)the Zhuhai Fundamental and Application Research(no.2220004002896)+2 种基金the Guangdong Introducing Innovative and Entrepreneurial Teams Program(no.2019ZT08Z656)the Shenzhen Science and Technology Program(no.KQTD20190929172522248)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(no.24qnpy160).
文摘Hydrogel electrolytes based on natural polymers have attracted increasing attention in zinc-ion batteries(ZIBs)powering wearable and implantable electronics,but designing natural polymer hydrogels with high ionic conductivity,excellent transference performance,and inhibited Zn dendrites is still challenging.Herein,two natural biocompatible polymers(sodium alginate(SA)and agarose(AG))are used to prepare composite hydrogel electrolytes ensuring electrostatic interaction between–COO–groups in SA and Zn^(2+)and coordination between C–O–C groups in AG and Zn^(2+).The as-obtained hydrogels exhibit an elevated ionic conductivity(25.05 mS cm^(−1))with a high transference number(0.75),useful for facilitated efficient Zn^(2+)transport.The theoretical calculations combined with experimental results reveal C–O–C groups endowing the as-prepared hydrogels with improved desolvation kinetics and capture ability of Zn^(2+)for achieving dendrite-free Zn deposition.In this way,the assembled Zn symmetric cell shows a long cycle life reaching 700 h at 0.2 mA cm^(−2).The exceptional biocompatibility of the hydrogels also results in cell viability assay with a survival rate above 93.5%.Overall,the proposed hydrogel electrolytes endow solid-state ZIBs with high discharge capacity,outstanding rate performance,long cycle life,good antifreeze capability,and impressive flexibility,useful features for future design and development of advanced ZIBs.
