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
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
Furfuryl ethyl ether(FEE)is considered as one of the most important candidates for biofuels due to its high-octane number.However,it is still challenging to produce FEE via the biomass-based route under mild condition...Furfuryl ethyl ether(FEE)is considered as one of the most important candidates for biofuels due to its high-octane number.However,it is still challenging to produce FEE via the biomass-based route under mild conditions.Here,we developed a photoinduced catalytic transfer hydrogenation(CTH)process for the efficient production of FEE through the reduction etherification of furfural(FF)using Na_(4)W_(10)O_(32)(NaDT),Pd/C,and ethanol as the hydrogen atom transfer(HAT)catalyst,hydrogenation catalyst,and the H donor,respectively.Notably,the introduction of brominated benzene(PhBr)as an additive significantly promoted the yield of FEE to 92.7%.A series of experiments and characterization results indicated that the attachment and detachment of Br atoms on Pd/C catalyst surface effectively regulate the balance between H^(+)sites and Pd sites in the NaDT+Pd/C catalytic system.The balance facilitates the preferential acetalization of FF catalyzed by H^(+)sites,followed by hydrogenation to efficiently produce FEE catalyzed by Pd sites.This photoinduced CTH process exhibits good stability and recyclability as well as universality for the transformation of various organic substrates under mild conditions.展开更多
The poor oxidation stability of ether-based solvents has long been a major challenge limiting their practical application.To enhance the oxidative stability of ether-based electrolytes,the physicochemical properties o...The poor oxidation stability of ether-based solvents has long been a major challenge limiting their practical application.To enhance the oxidative stability of ether-based electrolytes,the physicochemical properties of various glycol dimethyl ethers are screened,and diglyme(G2)is selected as the sole solvent for the electrolyte.Lithium bis(fluorosulfonyl)imide(LiFSI),a highly dissociative salt,is used as the primary salt;while lithium nitrate(LiNO_(3))and lithium difluorophosphate(LiDFP),which have small ionic sizes and strong binding energies,are added as secondary salts.The resulting electrolyte can modulate the electric double layer structure by NO_(3)^(-) and DFP^(-) on the cathode side,leading to an increased Liþconcentration that is originally repelled by the cathode.Additionally,the oxidation stability of the electrolyte is improved and the formed electrode-electrolyte interphase is more uniform and stable,thereby enhancing the electrochemical performance of the cells.As a result,cells assembled with a total of 1 M ternary lithium salts in G2 solvent can operate at high voltage of 4.4 V.The LijjNCM811 cells maintain 80.2%capacity retention after 270 cycles at room temperature,with an average Coulombic efficiency of 99.5%,and exhibit 88.4%capacity retention after 200 cycles at -30℃.展开更多
Objective:To isolate and identify active constituents from Gracilaria chorda extract prepared under subcritical water conditions at 210℃(GCSW210)and evaluate their anti-obesity and anti-diabetic effects in 3T3-L1 adi...Objective:To isolate and identify active constituents from Gracilaria chorda extract prepared under subcritical water conditions at 210℃(GCSW210)and evaluate their anti-obesity and anti-diabetic effects in 3T3-L1 adipocytes and high-fat diet(HFD)-induced obese zebrafish larvae.Methods:GCSW210 was fractionated through solvent partitioning,ion-exchange chromatography,and silica gel medium-pressure liquid chromatography,followed by preparative high performance liquid chromatography.At each step,bioactivities were assessed in 3T3-L1 adipocytes by Oil Red O staining and 2-NBDG uptake assays.The most active fractions were further purified,and isolated compounds were tested in HFD-induced obese zebrafish larvae.Results:Liquid chromatography-hyphenated analysis with reference standards identified two major compounds in GCSW210:5-hydroxymethylfurfural and bis(5-formylfurfuryl)ether.Both compounds significantly inhibited lipid accumulation in 3T3-L1 adipocytes and modulated gene expression associated with adipogenesis,glucose metabolism,and inflammation in zebrafish.They also enhanced glucose uptake,reduced circulating glucose levels,and improved insulin sensitivity.Notably,the effects were comparable to those of the crude GCSW210 extract.In silico docking studies confirmed stable interactions of both compounds with key metabolic and inflammatory targets,with bis(5-formylfurfuryl)ether showing stronger binding affinities.Conclusions:These findings suggest that 5-hydroxymethylfurfural and bis(5-formylfurfuryl)ether are key contributors to the therapeutic activity of Gracilaria chorda,highlighting its potential as a functional food ingredient for the prevention or management of metabolic disorders.展开更多
Charge transfer at the liquid(electrolyte)-solid(metal)interfaces is of fundamental importance to metal electrochemical deposition that further determines the reversibility and kinetics of energy-dense rechargeable me...Charge transfer at the liquid(electrolyte)-solid(metal)interfaces is of fundamental importance to metal electrochemical deposition that further determines the reversibility and kinetics of energy-dense rechargeable metal batteries(RMBs).We demonstrate the fast charge transfer at the electrolyte-metal interfaces for lithium metal by designing and synthesizing electrolytes with chiral solvents:R(or S)-1,2-dimethoxy pro pane(R-DMP or S-DMP)and R(or S)-4-methyl-1,3-dioxolane(R-MDOL or S-MDOL).The chiral-induced spin selectivity is considered to produce spin-polarized metal surfaces,enabling the improvement in charge transfer rate and efficiency.The deposited Li metal in chiral electrolytes shows smooth and uniform morphologies,as well as high initial(>95%)and average(~99.2%)Coulombic efficiency for Li metal stripping/plating process,thus prolonging the life-span of batteries using thin lithium anode(50μm)to 400 cycles till 80%capacity retention.This work provides a distinct approach to regulate metal deposition beyond the limitation of ion de-solvation.展开更多
Reclaimed water for irrigation or hydroponic cultivation provides exposure pathways for per-and polyfluoroalkyl substances(PFAS)to enter the human food chain.This study employed hydroponic methods to investigate the b...Reclaimed water for irrigation or hydroponic cultivation provides exposure pathways for per-and polyfluoroalkyl substances(PFAS)to enter the human food chain.This study employed hydroponic methods to investigate the behavior of legacy PFAS and emerging chlorinated polyfluoroalkyl ether sulfonic acids(Cl-PFESAs)in lettuce grown under environment-related exposure levels and assessed the human exposure risks from consuming contaminated lettuce.Overall,PFAS in lettuce were concentration-dependent,with long-chain PFAS tending to accumulate in roots and short-chain PFAS accumulating more in shoots.The enrichment of PFAS in lettuce was jointly influenced by their chain length and polar functional groups.Specifically,the root concentration factors(RCFs)of PFAS generally increased with increasing chain length,and RCF values of most perfluoroalkanesulfonic acids(PFSAs)were significantly higher than those of perfluoroalkyl carboxylic acids(PFCAs)with the same chain length(p<0.01),while the translocation factors(TFs)exhibited opposite trends.RCF values of perfluorooctane sulfonate(PFOS)and its alternatives,Cl-PFESAs,were ranked as follows:8:2 Cl-PFESA(mean:139)>6:2 Cl-PFESA(28.6)>PFOS(25.7),which was attributed to the increased molecular size and hydrophobicity resulting from the insertion of ether bonds and additional CF2 in 8:2 Cl-PFESA.Notably,TF value of 8:2 Cl-PFESA(mean:0.007)was the smallest among all PFAS,indicating 8:2 Cl-PFESA was difficult to transfer to nutritional compartments.Adults and children would exceed the most conservative health-based reference dose(RfD)by consuming approximately 15.9–148 g and 7.92–74.0 g of contaminated lettuce per day,implying high health risks.展开更多
Although solid-state polymer electrolytes(SPEs)are expected to solve the safety hazards and limited energy density in the energy storage systems,they still encounter an inferior electrode/electrolyte interface when pr...Although solid-state polymer electrolytes(SPEs)are expected to solve the safety hazards and limited energy density in the energy storage systems,they still encounter an inferior electrode/electrolyte interface when prepared in an ex situ manner.Recently,in situ polymerization of SPEs favor high interfacial infiltrability,improved interface contact,and reduced interface resistance,owing to the formation of a"superconformal"interface between electrode and electrolyte.Especially,in situ strategies employing ring-opening polymerization(ROP)are emerging as dazzling stars,further enabling moderate polymerization conditions,controllable molecular structure,and reduced interfacial side reaction.As the main monomers that can be in situ polymerized via the ROP strategy,cyclic ethers have been used to construct the CE-SPEs with many merits,including good battery electrochemical performances and a simple assembly process.Here,as a systematic summarization of the existing reports,this review focuses on the polymerization mechanism of ROP,the design principles of CE-SPEs electrolytes,and the recent application of in situ CE-SPEs.In particular,this review thoroughly discusses the selection of different cyclic monomers,initiators and various modification approaches in in situ fabricating CE-SPEs.Ending with offering future challenges and perspectives,this review envisions shedding light on the profound understanding and scientific guidance for further development of high-performance in situ CE-SPEs.展开更多
Background Insect meals have been identified as innovative and sustainable feedstuffs that could be used in ruminant nutrition.However,current research on the effects that their processing may have on rumen digestibil...Background Insect meals have been identified as innovative and sustainable feedstuffs that could be used in ruminant nutrition.However,current research on the effects that their processing may have on rumen digestibility and fatty acid(FA)biohydrogenation is scant.This trial aims to investigate the effects(i)of drying temperature of fullfat Hermetia illucens(HI)and Tenebrio molitor(TM)meals,and(ii)of residual ether extract(EE)content of defatted HI and TM meals,on their fermentation characteristics and FA of rumen digesta after 24-h in vitro rumen incubation.Methods The tested full-fat meals included four HI and four TM meals obtained applying drying temperatures ranging from 30℃ to 70℃,while the tested defatted meals consisted of five HI and two TM meals containing a residual EE content ranging from 4.7 to 19.7 g EE/100 g dry matter(DM).The applied statistical models(GLM ANOVA)tested the effects of insect species,drying temperature(full-fat meals)or EE content(defatted meals),and their interaction.Results Drying temperature had minor effects on in vitro ruminal digestibility and FA profile of rumen digesta.Irrespective of insect species,increasing the drying temperature led to a reduction of in vitro degradation of proteins from insect meals,as outlined by the significant decrease in ammonia production(-0.009 mmol/g DM and-0.126 g/100 g total N for each additional 1℃).Irrespective of insect species,defatting increased total gas,volatile fatty acids(VFA)and CH_(4) productions,and the proportions of total saturated and branched-chain FA in rumen digesta(+0.038 mmol/g DM,+0.063 mmol/g DM,+12.9μmol/g DM,+0.18 g/100 g FA,and+0.19 g/100 g FA for each reduced 1 g EE/100 g DM,respectively),and reduced the proportion of total PUFA(-0.12 g/100 g FA).Conclusions The applied drying temperatures of full-fat insect meals are too low to exert impactful effects on rumen digestibility and FA biohydrogenation.Fat lowered fermentation activity,probably because of an inhibitory effect on rumen microbiota.The increased ruminal digestibility of defatted insect meals suggests that they can be more suitable to be used in ruminant nutrition than full-fat ones.展开更多
Heterogeneous precious metal catalysts are prone to agglomeration during preparation,requiring high usage with consequently high costs.Maximizing the efficiency of precious-metal utilization is of great significance i...Heterogeneous precious metal catalysts are prone to agglomeration during preparation,requiring high usage with consequently high costs.Maximizing the efficiency of precious-metal utilization is of great significance in the design of supported precious metal catalysts.Herein,2,2'-bipyridyl-5,5'-dicarboxylic acid was used as the ligand in constructing the UiO-67-Ce-BPyDC framework with Ce^(4+)coordination.This framework enables precise adsorption and coordination of Pd2+at the nitrogen sites of pyridine,promoting high dispersion of the Pd species at a single site,thereby facilitating controlled palladium loading.This precursor was used to fabricate supported Pd-based catalysts on CeO_(2)(Pd-N/CeO_(2)-P)via pyrolysis.Notably,because the Pd species are homogeneously distributed on CeO_(2)with strong interactions,Pd-N/CeO_(2)-P exhibits remarkable efficiency in cleaving the C-O bonds of diphenyl ether(DPE)to produce cyclohexanol,with a selectivity of 72.1%.The origin of the high selectivity of cyclohexanol is further elucidated using theoretical calculations;that is,DPE undergoes not only hydrogenolysis on Pd-N/CeO_(2)-P,but also hydrolysis to produce more cyclohexanol.This study not only demonstrates a successful strategy for designing highly dispersed metal catalysts,but also underscores the importance of such tailored catalysts in the advancement of sustainable lignin depolymerization technologies.展开更多
Chiral aryl cyclohex-3-en ether scaffold is widely present in bioactive natural products and drugs.The exploitation of efficient and enantioselective methods for the construction of aryl cyclohex-3-en ether scaffold i...Chiral aryl cyclohex-3-en ether scaffold is widely present in bioactive natural products and drugs.The exploitation of efficient and enantioselective methods for the construction of aryl cyclohex-3-en ether scaffold is significant.Herein we disclose a chiral N,N’-dioxide/Lewis acid complex-catalyzed asymmetric inverse-electron-demand Diels-Alder(IEDDA)reaction using electron-deficient 3-carboalkoxyl-2-pyrones and less electron-enriched aryl enol ethers as reactants.A wide range of non-and 1,2-disubstituted acyclic aryl enol ethers are applicable to deliver diverse chiral bridged bicyclic lactones in high yields and stereoselectivities(up to 96%yield,>20:1 dr,97:3 er).The bridged bicyclic lactone core can be easily converted into chiral aryl cyclohex-3-en ether scaffold.Notably,DFT calculations revealed a stepwise and endo mechanism to explain the high enantioselectivity controlled by the cooperative effect of the steric factors and the dispersion interactions between ligands and enol ethers.展开更多
Background:Fruits of Indian gooseberry or Amla or Aonla(Phyllanthus emblica)are important ingredients in many Ayurvedic medicines,but little is known about its leaves.Methods:Different extracts and crude alkaloids of ...Background:Fruits of Indian gooseberry or Amla or Aonla(Phyllanthus emblica)are important ingredients in many Ayurvedic medicines,but little is known about its leaves.Methods:Different extracts and crude alkaloids of P.emblica leaves were evaluated for their antimicrobial activity against clinically important microbes using agar well diffusion assay.The antimicrobial activity of methanolic extract(ME)of P.emblica leaves was also compared with similarly prepared methanolic extracts from leaves of Yellow Kaner(Cascabela peruviana),Parijaat or Harsingar(Nyctanthes arbor-tristis),Custard apple(Annona squamosa),Garlic vine(Mansoa alliacea),Shami plant(Prosopis cineraria),Madar(Calotropis gigantea),and Bael(Aegle marmelos).Results:The ME of leaves of P.emblica was the most potent preparation against bacteria and yeast.Of the 338 strains of microbes belonging to 100 species(96 bacteria and four Candida species),the ME of P.emblica inhibited the growth of 300 strains.A total of 84.62%,96.39%,and 100%of 221 G−bacteria,111 G+bacteria,and 6 Candida species strains,respectively,were inhibited by ME of P.emblica leaves at≤36 mg/well.The aqueous extract of P.emblica leaves also inhibited a similar number of bacterial strains,but at higher concentrations,while the ether extract could inhibit only staphylococci.The alkaloid from P.emblica leaves and the ME from leaves of other plants had insignificant antimicrobial activity at similar≤36 mg/well concentration.Conclusion:The study concluded that the ME of P.emblica leaves may be a useful source of a potent,wide-spectrum antimicrobial substance(s).展开更多
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.
文摘Furfuryl ethyl ether(FEE)is considered as one of the most important candidates for biofuels due to its high-octane number.However,it is still challenging to produce FEE via the biomass-based route under mild conditions.Here,we developed a photoinduced catalytic transfer hydrogenation(CTH)process for the efficient production of FEE through the reduction etherification of furfural(FF)using Na_(4)W_(10)O_(32)(NaDT),Pd/C,and ethanol as the hydrogen atom transfer(HAT)catalyst,hydrogenation catalyst,and the H donor,respectively.Notably,the introduction of brominated benzene(PhBr)as an additive significantly promoted the yield of FEE to 92.7%.A series of experiments and characterization results indicated that the attachment and detachment of Br atoms on Pd/C catalyst surface effectively regulate the balance between H^(+)sites and Pd sites in the NaDT+Pd/C catalytic system.The balance facilitates the preferential acetalization of FF catalyzed by H^(+)sites,followed by hydrogenation to efficiently produce FEE catalyzed by Pd sites.This photoinduced CTH process exhibits good stability and recyclability as well as universality for the transformation of various organic substrates under mild conditions.
文摘The poor oxidation stability of ether-based solvents has long been a major challenge limiting their practical application.To enhance the oxidative stability of ether-based electrolytes,the physicochemical properties of various glycol dimethyl ethers are screened,and diglyme(G2)is selected as the sole solvent for the electrolyte.Lithium bis(fluorosulfonyl)imide(LiFSI),a highly dissociative salt,is used as the primary salt;while lithium nitrate(LiNO_(3))and lithium difluorophosphate(LiDFP),which have small ionic sizes and strong binding energies,are added as secondary salts.The resulting electrolyte can modulate the electric double layer structure by NO_(3)^(-) and DFP^(-) on the cathode side,leading to an increased Liþconcentration that is originally repelled by the cathode.Additionally,the oxidation stability of the electrolyte is improved and the formed electrode-electrolyte interphase is more uniform and stable,thereby enhancing the electrochemical performance of the cells.As a result,cells assembled with a total of 1 M ternary lithium salts in G2 solvent can operate at high voltage of 4.4 V.The LijjNCM811 cells maintain 80.2%capacity retention after 270 cycles at room temperature,with an average Coulombic efficiency of 99.5%,and exhibit 88.4%capacity retention after 200 cycles at -30℃.
文摘Objective:To isolate and identify active constituents from Gracilaria chorda extract prepared under subcritical water conditions at 210℃(GCSW210)and evaluate their anti-obesity and anti-diabetic effects in 3T3-L1 adipocytes and high-fat diet(HFD)-induced obese zebrafish larvae.Methods:GCSW210 was fractionated through solvent partitioning,ion-exchange chromatography,and silica gel medium-pressure liquid chromatography,followed by preparative high performance liquid chromatography.At each step,bioactivities were assessed in 3T3-L1 adipocytes by Oil Red O staining and 2-NBDG uptake assays.The most active fractions were further purified,and isolated compounds were tested in HFD-induced obese zebrafish larvae.Results:Liquid chromatography-hyphenated analysis with reference standards identified two major compounds in GCSW210:5-hydroxymethylfurfural and bis(5-formylfurfuryl)ether.Both compounds significantly inhibited lipid accumulation in 3T3-L1 adipocytes and modulated gene expression associated with adipogenesis,glucose metabolism,and inflammation in zebrafish.They also enhanced glucose uptake,reduced circulating glucose levels,and improved insulin sensitivity.Notably,the effects were comparable to those of the crude GCSW210 extract.In silico docking studies confirmed stable interactions of both compounds with key metabolic and inflammatory targets,with bis(5-formylfurfuryl)ether showing stronger binding affinities.Conclusions:These findings suggest that 5-hydroxymethylfurfural and bis(5-formylfurfuryl)ether are key contributors to the therapeutic activity of Gracilaria chorda,highlighting its potential as a functional food ingredient for the prevention or management of metabolic disorders.
基金supported by the National Key R&D Program of China(2021YFB2500300)the National Natural Science Foundation of China(22372083,52201259)+1 种基金the Natural Science Foundation of Tianjin(22JCZDJC00380)Young Elite Scientist Sponsorship Program by CAST。
文摘Charge transfer at the liquid(electrolyte)-solid(metal)interfaces is of fundamental importance to metal electrochemical deposition that further determines the reversibility and kinetics of energy-dense rechargeable metal batteries(RMBs).We demonstrate the fast charge transfer at the electrolyte-metal interfaces for lithium metal by designing and synthesizing electrolytes with chiral solvents:R(or S)-1,2-dimethoxy pro pane(R-DMP or S-DMP)and R(or S)-4-methyl-1,3-dioxolane(R-MDOL or S-MDOL).The chiral-induced spin selectivity is considered to produce spin-polarized metal surfaces,enabling the improvement in charge transfer rate and efficiency.The deposited Li metal in chiral electrolytes shows smooth and uniform morphologies,as well as high initial(>95%)and average(~99.2%)Coulombic efficiency for Li metal stripping/plating process,thus prolonging the life-span of batteries using thin lithium anode(50μm)to 400 cycles till 80%capacity retention.This work provides a distinct approach to regulate metal deposition beyond the limitation of ion de-solvation.
基金supported by the Fundamental Research Funds for Central Non-profit Scientific Institution(No.1610132022015)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0750200)the National Natural Science Foundation of China(No.22176198).
文摘Reclaimed water for irrigation or hydroponic cultivation provides exposure pathways for per-and polyfluoroalkyl substances(PFAS)to enter the human food chain.This study employed hydroponic methods to investigate the behavior of legacy PFAS and emerging chlorinated polyfluoroalkyl ether sulfonic acids(Cl-PFESAs)in lettuce grown under environment-related exposure levels and assessed the human exposure risks from consuming contaminated lettuce.Overall,PFAS in lettuce were concentration-dependent,with long-chain PFAS tending to accumulate in roots and short-chain PFAS accumulating more in shoots.The enrichment of PFAS in lettuce was jointly influenced by their chain length and polar functional groups.Specifically,the root concentration factors(RCFs)of PFAS generally increased with increasing chain length,and RCF values of most perfluoroalkanesulfonic acids(PFSAs)were significantly higher than those of perfluoroalkyl carboxylic acids(PFCAs)with the same chain length(p<0.01),while the translocation factors(TFs)exhibited opposite trends.RCF values of perfluorooctane sulfonate(PFOS)and its alternatives,Cl-PFESAs,were ranked as follows:8:2 Cl-PFESA(mean:139)>6:2 Cl-PFESA(28.6)>PFOS(25.7),which was attributed to the increased molecular size and hydrophobicity resulting from the insertion of ether bonds and additional CF2 in 8:2 Cl-PFESA.Notably,TF value of 8:2 Cl-PFESA(mean:0.007)was the smallest among all PFAS,indicating 8:2 Cl-PFESA was difficult to transfer to nutritional compartments.Adults and children would exceed the most conservative health-based reference dose(RfD)by consuming approximately 15.9–148 g and 7.92–74.0 g of contaminated lettuce per day,implying high health risks.
基金supported by the National Natural Science Foundation of China(22022813)the Zhejiang Provincial Natural Science Foundation of China(LQ24B030002)the China Postdoctoral Science Foundation(2022M722729,2023T160571).
文摘Although solid-state polymer electrolytes(SPEs)are expected to solve the safety hazards and limited energy density in the energy storage systems,they still encounter an inferior electrode/electrolyte interface when prepared in an ex situ manner.Recently,in situ polymerization of SPEs favor high interfacial infiltrability,improved interface contact,and reduced interface resistance,owing to the formation of a"superconformal"interface between electrode and electrolyte.Especially,in situ strategies employing ring-opening polymerization(ROP)are emerging as dazzling stars,further enabling moderate polymerization conditions,controllable molecular structure,and reduced interfacial side reaction.As the main monomers that can be in situ polymerized via the ROP strategy,cyclic ethers have been used to construct the CE-SPEs with many merits,including good battery electrochemical performances and a simple assembly process.Here,as a systematic summarization of the existing reports,this review focuses on the polymerization mechanism of ROP,the design principles of CE-SPEs electrolytes,and the recent application of in situ CE-SPEs.In particular,this review thoroughly discusses the selection of different cyclic monomers,initiators and various modification approaches in in situ fabricating CE-SPEs.Ending with offering future challenges and perspectives,this review envisions shedding light on the profound understanding and scientific guidance for further development of high-performance in situ CE-SPEs.
基金partially granted by the Hi-Ga project,which is part of the programme of the Green ERA-Hub that has received funding from the European Union’s Horizon Europe research and innovation programme under Grant Agreement No.101056828self-financed by the DINAMIC team of the UMR Herbivores(INRAE,VetAgro Sup,Saint-Genès-Champanelle,France)。
文摘Background Insect meals have been identified as innovative and sustainable feedstuffs that could be used in ruminant nutrition.However,current research on the effects that their processing may have on rumen digestibility and fatty acid(FA)biohydrogenation is scant.This trial aims to investigate the effects(i)of drying temperature of fullfat Hermetia illucens(HI)and Tenebrio molitor(TM)meals,and(ii)of residual ether extract(EE)content of defatted HI and TM meals,on their fermentation characteristics and FA of rumen digesta after 24-h in vitro rumen incubation.Methods The tested full-fat meals included four HI and four TM meals obtained applying drying temperatures ranging from 30℃ to 70℃,while the tested defatted meals consisted of five HI and two TM meals containing a residual EE content ranging from 4.7 to 19.7 g EE/100 g dry matter(DM).The applied statistical models(GLM ANOVA)tested the effects of insect species,drying temperature(full-fat meals)or EE content(defatted meals),and their interaction.Results Drying temperature had minor effects on in vitro ruminal digestibility and FA profile of rumen digesta.Irrespective of insect species,increasing the drying temperature led to a reduction of in vitro degradation of proteins from insect meals,as outlined by the significant decrease in ammonia production(-0.009 mmol/g DM and-0.126 g/100 g total N for each additional 1℃).Irrespective of insect species,defatting increased total gas,volatile fatty acids(VFA)and CH_(4) productions,and the proportions of total saturated and branched-chain FA in rumen digesta(+0.038 mmol/g DM,+0.063 mmol/g DM,+12.9μmol/g DM,+0.18 g/100 g FA,and+0.19 g/100 g FA for each reduced 1 g EE/100 g DM,respectively),and reduced the proportion of total PUFA(-0.12 g/100 g FA).Conclusions The applied drying temperatures of full-fat insect meals are too low to exert impactful effects on rumen digestibility and FA biohydrogenation.Fat lowered fermentation activity,probably because of an inhibitory effect on rumen microbiota.The increased ruminal digestibility of defatted insect meals suggests that they can be more suitable to be used in ruminant nutrition than full-fat ones.
基金Project supported by the National Natural Science Foundation of China(22221001,22131007,22102193)the National Key R&D Program of China(2021YFA1501101,2022YFA1504601)+1 种基金the 111 Project(B20027)a Startup Program of the State Key Laboratory for Oxo Synthesis and Selective Oxidation of LICP(EOSX0184)。
文摘Heterogeneous precious metal catalysts are prone to agglomeration during preparation,requiring high usage with consequently high costs.Maximizing the efficiency of precious-metal utilization is of great significance in the design of supported precious metal catalysts.Herein,2,2'-bipyridyl-5,5'-dicarboxylic acid was used as the ligand in constructing the UiO-67-Ce-BPyDC framework with Ce^(4+)coordination.This framework enables precise adsorption and coordination of Pd2+at the nitrogen sites of pyridine,promoting high dispersion of the Pd species at a single site,thereby facilitating controlled palladium loading.This precursor was used to fabricate supported Pd-based catalysts on CeO_(2)(Pd-N/CeO_(2)-P)via pyrolysis.Notably,because the Pd species are homogeneously distributed on CeO_(2)with strong interactions,Pd-N/CeO_(2)-P exhibits remarkable efficiency in cleaving the C-O bonds of diphenyl ether(DPE)to produce cyclohexanol,with a selectivity of 72.1%.The origin of the high selectivity of cyclohexanol is further elucidated using theoretical calculations;that is,DPE undergoes not only hydrogenolysis on Pd-N/CeO_(2)-P,but also hydrolysis to produce more cyclohexanol.This study not only demonstrates a successful strategy for designing highly dispersed metal catalysts,but also underscores the importance of such tailored catalysts in the advancement of sustainable lignin depolymerization technologies.
基金National Natural Science Foundation of China(Nos.22001177,22203023)Guangdong Pearl River Talent Program(no.2021QN020268)+3 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515012381,2022A1515011859)Shenzhen Bay Laboratory Startup Fund(No.S201100003)Major Program of Shenzhen Bay Laboratory(No.S211101001-4)Shenzhen Bay Qihang Fellow Program(No.QH23001)for generous financial support.
文摘Chiral aryl cyclohex-3-en ether scaffold is widely present in bioactive natural products and drugs.The exploitation of efficient and enantioselective methods for the construction of aryl cyclohex-3-en ether scaffold is significant.Herein we disclose a chiral N,N’-dioxide/Lewis acid complex-catalyzed asymmetric inverse-electron-demand Diels-Alder(IEDDA)reaction using electron-deficient 3-carboalkoxyl-2-pyrones and less electron-enriched aryl enol ethers as reactants.A wide range of non-and 1,2-disubstituted acyclic aryl enol ethers are applicable to deliver diverse chiral bridged bicyclic lactones in high yields and stereoselectivities(up to 96%yield,>20:1 dr,97:3 er).The bridged bicyclic lactone core can be easily converted into chiral aryl cyclohex-3-en ether scaffold.Notably,DFT calculations revealed a stepwise and endo mechanism to explain the high enantioselectivity controlled by the cooperative effect of the steric factors and the dispersion interactions between ligands and enol ethers.
基金supported by grants from CAAST-ACLH(NAHEP/CAAST/2018-19)of the ICAR-World Bank-funded National Agricultural Higher Education Project(NAHEP).
文摘Background:Fruits of Indian gooseberry or Amla or Aonla(Phyllanthus emblica)are important ingredients in many Ayurvedic medicines,but little is known about its leaves.Methods:Different extracts and crude alkaloids of P.emblica leaves were evaluated for their antimicrobial activity against clinically important microbes using agar well diffusion assay.The antimicrobial activity of methanolic extract(ME)of P.emblica leaves was also compared with similarly prepared methanolic extracts from leaves of Yellow Kaner(Cascabela peruviana),Parijaat or Harsingar(Nyctanthes arbor-tristis),Custard apple(Annona squamosa),Garlic vine(Mansoa alliacea),Shami plant(Prosopis cineraria),Madar(Calotropis gigantea),and Bael(Aegle marmelos).Results:The ME of leaves of P.emblica was the most potent preparation against bacteria and yeast.Of the 338 strains of microbes belonging to 100 species(96 bacteria and four Candida species),the ME of P.emblica inhibited the growth of 300 strains.A total of 84.62%,96.39%,and 100%of 221 G−bacteria,111 G+bacteria,and 6 Candida species strains,respectively,were inhibited by ME of P.emblica leaves at≤36 mg/well.The aqueous extract of P.emblica leaves also inhibited a similar number of bacterial strains,but at higher concentrations,while the ether extract could inhibit only staphylococci.The alkaloid from P.emblica leaves and the ME from leaves of other plants had insignificant antimicrobial activity at similar≤36 mg/well concentration.Conclusion:The study concluded that the ME of P.emblica leaves may be a useful source of a potent,wide-spectrum antimicrobial substance(s).
