The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats.Due to the low reactivity of the carbonyl group in esters,a high reaction tempera...The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats.Due to the low reactivity of the carbonyl group in esters,a high reaction temperature(>250℃)is the prerequisite to ensure high conversion of esters.Here,we report a highly dispersed MoO_(x)-Ru/C bimetallic catalyst for the efficient hydrogenolysis of esters to alkanes under 150°C.The optimal catalyst exhibits>99%conversion of methyl stearate and 99%selectivity to diesel-range alkanes,reaching a high rate of up to 2.0 mmol gcat^(–1)h^(–1),5 times higher than that of Ru/C catalyst(MoO_(x)/C is inert).Integrated experimental and theoretical investigations attribute the high performance to the abundant MoO_(x)-Ru interfacial sites on the catalyst surface,which offers high activity for the C–O cleavage of esters.Furthermore,the dispersed MoO_(x)species significantly weaken the hydrocracking activity of the metallic Ru for C–C bonds,thus yielding alkane products without carbon loss.This study provides a facile and novel strategy for the design of high-performance heterogeneous catalysts for the hydrodeoxygenation of biomass-derived esters to alkane products.展开更多
Fifty agricultural soil samples collected from Fuzhou,southeast China,were first investigated for the occurrence,distribution,and potential risks of twelve organophosphate esters(OPEs).The total concentration of OPEs(...Fifty agricultural soil samples collected from Fuzhou,southeast China,were first investigated for the occurrence,distribution,and potential risks of twelve organophosphate esters(OPEs).The total concentration of OPEs(ΣOPEs)in soil ranged from 1.33 to 96.5 ng/g dry weight(dw),with an average value of 17.1 ng/g dw.Especially,halogenated-OPEs were the predominant group with amean level of 9.75 ng/g dw,and tris(1-chloro-2-propyl)phosphate(TCIPP)was the most abundant OPEs,accounting for 51.1%ofΣOPEs.The concentrations of TCIPP andΣOPEs were found to be significantly higher(P<0.05)in soils of urban areas than those in suburban areas.In addition,the use of agricultural plastic films and total organic carbon had a positive effect on the occurrence of OPE in this study.The positive matrix factorization model suggested complex sources of OPEs in agricultural soils from Fuzhou.The ecological risk assessment demonstrated that tricresyl phosphate presented a medium risk to land-based organisms(0.1≤risk quotient<1.0).Nevertheless,the carcinogenic and noncarcinogenic risks for human exposure to OPEs through soil ingestion and dermal absorption were negligible.These findings would facilitate further investigations into the pollution management and risk control of OPEs.展开更多
Phthalic acid esters(PAEs)are a group of compounds widespread in the environment.To investigate the occurrence and accumulation characteristics of PAEs,surface water samples were collected from the Three Gorges Reserv...Phthalic acid esters(PAEs)are a group of compounds widespread in the environment.To investigate the occurrence and accumulation characteristics of PAEs,surface water samples were collected from the Three Gorges Reservoir area,China.The total concentrations of∑_(11)analyzed PAEs(11PAEs)in the collected water samples ranging from 197.7 to 1,409.3 ng/L(mean±IQR:583.1±308.4 ng/L).While DEHP was the most frequently detected PAE,DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3%of the∑_(11)PAEs.The concentrations of the∑_(11)PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from themiddle reaches.To better understand the transport and fate of the PAEs,seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction(QWASI).The simulated and measured values were close for most PAEs,and differences are within one order of magnitude even for the worst one.For all simulated PAEs,water and particle inflow were main sources in the reservoir,whereas water outflow and degradation in water were important removal pathways.The contribution ratios of different sources/losses varied fromPAEs,depending on their properties.The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based onmonitoring or simulating results were all far exceeded the safety threshold value,implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area.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
A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is ver...A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is very simple.A number of diazo esters and gem-difluoroalkenes are suitable for this reaction(36 examples),providing the desired products in good yields with excellent diastereoselectivity(>20∶1).展开更多
Phthalic acid esters(PAEs)are widely released into the environment due to industrial and agricultural activities.This poses significant risks,not only to crops grown on contaminated soil but also to humans.PAEs enter ...Phthalic acid esters(PAEs)are widely released into the environment due to industrial and agricultural activities.This poses significant risks,not only to crops grown on contaminated soil but also to humans.PAEs enter the human body through the food chain,causing potential health hazards.Endophytic bacteria have demonstrated a significant potential as effective bioremediation agents,with specialized mechanisms of PAEs degradation.Endophytic bacteria such as Rhodococcus,Pseudomonas and Sphingomona recognize root exudates,adhere to and penetrate root surfaces,and ultimately colonize crops.They form symbiotic relationships with crops,obtaining nutrients and habitats from crops,meanwhile,promoting plant growth and health through hormone production,nutrient regulation,and the suppression of pathogenic microorganisms.Furthermore,endophytic bacteria efficiently degrade PAEs in soil-crop systems through synergistic interactions with indigenous rhizosphere microflora and regulatory effects on enzyme activity in crops.Here,we review the role of endophytic bacteria in the bioremediation of PAEs-contaminated crops and soils.In addition,we discuss the scarcity of endophytic bacterial strains with a confirmed ability to degrade PAEs,and underscore the lack of the research on the mechanisms of PAEs degradation by these bacteria.This review also points out that future study should investigate the molecular mechanisms underlying the interaction between endophytic bacteria and PAEs to offer novel insights and solutions for environmental protection and sustainable agricultural development.展开更多
An enantioselective catalytic method for the direct [4 + 1] annulation of yne–allylic acetates with pyrazolones has been realized by a copper-catalyzed remote strategy. A variety of enantioenriched spiropyrazolones a...An enantioselective catalytic method for the direct [4 + 1] annulation of yne–allylic acetates with pyrazolones has been realized by a copper-catalyzed remote strategy. A variety of enantioenriched spiropyrazolones are rapidly accessed in high yields with moderate to good enantiocontrol. The facile follow-up transformations highlight its potential utility in the synthesis of diverse spiropyrazolones building blocks.展开更多
Background:In today’s context,vegetable oils,commonly used in culinary practices such as frying and baking,are integral to numerous daily dietary choices.Palm oil,a frequently employed vegetable oil,raises concerns s...Background:In today’s context,vegetable oils,commonly used in culinary practices such as frying and baking,are integral to numerous daily dietary choices.Palm oil,a frequently employed vegetable oil,raises concerns surrounding food safety,thus presenting a significant challenge.Methods:This research aims to enhance consumer awareness regarding the potential health risks associated with 3-monochloropropane-1,2-diol(3-MCPD)and glycidyl fatty acid esters(GEs)commonly found in food and edible oil products.The study endeavours to apprise consumers of these health risks through a comprehensive survey.The survey enlisted the participation of 120 respondents within the age bracket of 18 years to those above 36 years(capped at 50 years).Results:Strikingly,a significant proportion,ranging from 88%to 89%,demonstrated a lack of awareness concerning the potential risks associated with 3-MCPD and GEs in food products.Conclusion:This study underscores the urgency of augmenting consumer's awareness levels regarding 3-MCPD and GEs.Furthermore,it promotes a more detailed examination of Malaysian edible oils and food products available in the market to establish an appropriate Tolerable Daily Intake for the Malaysian population.This research contributes to the broader discourse on food safety and public health by highlighting these crucial facets.展开更多
Caffeic acid phenethyl ester (CAPE) and sixteen substituted cinnamic acid phenethyl esters were prepared via conventional procedures in order to test their in vitro anticancer activities by either MTT assay or SRB...Caffeic acid phenethyl ester (CAPE) and sixteen substituted cinnamic acid phenethyl esters were prepared via conventional procedures in order to test their in vitro anticancer activities by either MTT assay or SRB assay on six different human cancer cell lines. The results indicated that in the concentration of 10 μmol·L -1 the lead compound CAPE possessed anticancer activities against human HL 60, Bel 7402, and Hela cell lines, and two other compounds possessed potent anticancer activities against Bel 7402 and Hela cell lines.展开更多
A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas...A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.展开更多
As one of the most essential components in photocuring system,photoinitiators(PIs)exert a crucial influence on the properties of the cured product.However,commercially available PIs encounter challenges in simultaneou...As one of the most essential components in photocuring system,photoinitiators(PIs)exert a crucial influence on the properties of the cured product.However,commercially available PIs encounter challenges in simultaneously achieving efficient photoinitiation performance and excellent light absorption properties,significantly limiting their applications in various fields.Here,two bis-chalcones and four corresponding oxime esters(OXEs)were designed and synthesized as highly efficient PIs.Featuring a structure comprising bis-chalcone and two diphenyl sulfides,the conjugated systems in these compounds enhance their light-absorption properties in near-ultraviolet and visible region,effectively.Both the frontier molecular orbital simulations and excited state calculations suggest the contribution of sulfur atoms to electron delocalization and the formation of conjugated structure.Due to the high reactivity of the N–O bond in OXE moiety,the four OXEs exhibit exceptional free radical photoinitiating ability in commercial acrylic monomers/oligomers with LED@365nm as light source.Notably,one of them demonstrates superior performance in the photoinitiation of multifunctional crosslinker,achieving more than 70%conversion within 3 s,coupled with outstanding absorption at 365 nm.These chalcone-based OXEs are considered to exert significant potential in the realm of free radical photocuring.展开更多
Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In ...Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.展开更多
Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polyme...Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polymers has become an attractive subject.Herein,a new monomer of thiosalicylic methyl glycolide(TSMG)was synthesized using one-pot method and high molecular weight poly(thiosalicylic methyl glycolide)(PTSMG,M_(n) up to 300 kDa)can be obtained via the ring-opening polymerization(ROP)of TSMG.PTSMG exhibits good closed-loop recyclability and hydrolytic degradability,where PTSMG can generate pristine monomers through sublimation thermal depolymerization conditions due to the presence of thiophenol ester bond in the polymer chains,and can be degraded rapidly in aqueous solution,which provides a potential solution to the current plastic pollution problem.展开更多
Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in ...Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor.The conversion achieved nearly 100%within 5 h under the reaction temperature,the mass ratio of catalyst to fatty acid methyl esters(FAMEs),and isobutanol to FAMEs total molar ratio of 180℃,0.4%(mass),and 5.4:1,respectively.In addition,kinetic model of the transesterification reaction was developed at 150–190℃.The calculated activation energy was 48.93 kJ·mol^(-1).Then,the epoxidation of obtained fatty acid isobutyl esters(FABEs)was conducted in the presence of formic acid and hydrogen peroxide.The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate(DOP)and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters(Ep-FAMEs).The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP.In addition,the extraction resistance and migration stability of Ep-FABEs were better than those of EpFAMEs.Overall,the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer.展开更多
An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of th...An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.展开更多
A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride ...A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)展开更多
To investigate the phytochemical constituents of aboveground parts of Croton tiglium L. （family Euphorbiaceae）, its ingredients were isolated by repeated chromatography on silica gel, Sephadex LH-20, ODS and prepara...To investigate the phytochemical constituents of aboveground parts of Croton tiglium L. （family Euphorbiaceae）, its ingredients were isolated by repeated chromatography on silica gel, Sephadex LH-20, ODS and preparative HPLC. Their structures were identified based on 1D, 2D NMR and mass spectral analysis. A total of 10 phorbol esters were obtained. Among them, compound 1 （12-O-（2-methyl）butyryl-4ct-deoxyphorbol-β-isobutyrate） and compound 10 （20-formyl-4a-deoxyphorbol- β-acetate） were two new compounds, and the other eight were known compounds.展开更多
The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples wer...The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples were collected in June 2010.Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry.Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L,respectively.Fluoranthene,naphthalene,pyrene,phenanthrene,di-2ethylhexyl phthalate,and di-n-butyl phthalate were the most abundant compounds in the samples.The water samples were moderately polluted with benzo[a]pyrene according to China＇s environmental quality standard for surface water.The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake,Wuxi City and the western section of Yangchenghu Lake.Potential sources of pollution at S7 were petroleum combustion and the plastics industry,and at Yangchenghu Lake were petroleum combustion and domestic waste.Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines.There were no obvious sources of pollution for the other water samples.These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs.展开更多
Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunli...Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.展开更多
文摘The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats.Due to the low reactivity of the carbonyl group in esters,a high reaction temperature(>250℃)is the prerequisite to ensure high conversion of esters.Here,we report a highly dispersed MoO_(x)-Ru/C bimetallic catalyst for the efficient hydrogenolysis of esters to alkanes under 150°C.The optimal catalyst exhibits>99%conversion of methyl stearate and 99%selectivity to diesel-range alkanes,reaching a high rate of up to 2.0 mmol gcat^(–1)h^(–1),5 times higher than that of Ru/C catalyst(MoO_(x)/C is inert).Integrated experimental and theoretical investigations attribute the high performance to the abundant MoO_(x)-Ru interfacial sites on the catalyst surface,which offers high activity for the C–O cleavage of esters.Furthermore,the dispersed MoO_(x)species significantly weaken the hydrocracking activity of the metallic Ru for C–C bonds,thus yielding alkane products without carbon loss.This study provides a facile and novel strategy for the design of high-performance heterogeneous catalysts for the hydrodeoxygenation of biomass-derived esters to alkane products.
基金supported by the Open Fund of the Laboratory for Earth Surface Processes,Ministry of Education,Peking University,Beijing,China,and the Cultivation Fund Program for Excellent Dissertation in Fujian Normal University,China(No.LWPYS202315)the Research Start-up Fund of Fujian Normal University,China(No.Y0720304X13).
文摘Fifty agricultural soil samples collected from Fuzhou,southeast China,were first investigated for the occurrence,distribution,and potential risks of twelve organophosphate esters(OPEs).The total concentration of OPEs(ΣOPEs)in soil ranged from 1.33 to 96.5 ng/g dry weight(dw),with an average value of 17.1 ng/g dw.Especially,halogenated-OPEs were the predominant group with amean level of 9.75 ng/g dw,and tris(1-chloro-2-propyl)phosphate(TCIPP)was the most abundant OPEs,accounting for 51.1%ofΣOPEs.The concentrations of TCIPP andΣOPEs were found to be significantly higher(P<0.05)in soils of urban areas than those in suburban areas.In addition,the use of agricultural plastic films and total organic carbon had a positive effect on the occurrence of OPE in this study.The positive matrix factorization model suggested complex sources of OPEs in agricultural soils from Fuzhou.The ecological risk assessment demonstrated that tricresyl phosphate presented a medium risk to land-based organisms(0.1≤risk quotient<1.0).Nevertheless,the carcinogenic and noncarcinogenic risks for human exposure to OPEs through soil ingestion and dermal absorption were negligible.These findings would facilitate further investigations into the pollution management and risk control of OPEs.
基金supported by the Innovation Fund of Nanjing Institute of Environmental Science,Ministry of Ecology and Environment,China(No.ZX2023QT003)the National Natural Science Foundation of China(No.22306130)+1 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB789)the Ecological Environment Research Project of Jiangsu Province,China(No.2022014).
文摘Phthalic acid esters(PAEs)are a group of compounds widespread in the environment.To investigate the occurrence and accumulation characteristics of PAEs,surface water samples were collected from the Three Gorges Reservoir area,China.The total concentrations of∑_(11)analyzed PAEs(11PAEs)in the collected water samples ranging from 197.7 to 1,409.3 ng/L(mean±IQR:583.1±308.4 ng/L).While DEHP was the most frequently detected PAE,DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3%of the∑_(11)PAEs.The concentrations of the∑_(11)PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from themiddle reaches.To better understand the transport and fate of the PAEs,seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction(QWASI).The simulated and measured values were close for most PAEs,and differences are within one order of magnitude even for the worst one.For all simulated PAEs,water and particle inflow were main sources in the reservoir,whereas water outflow and degradation in water were important removal pathways.The contribution ratios of different sources/losses varied fromPAEs,depending on their properties.The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based onmonitoring or simulating results were all far exceeded the safety threshold value,implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area.
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A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is very simple.A number of diazo esters and gem-difluoroalkenes are suitable for this reaction(36 examples),providing the desired products in good yields with excellent diastereoselectivity(>20∶1).
基金supported by the National Natural Science Foundation of China(No.22161132011)Jiangsu Provincial Special Fund for S&T Innovation in Carbon Emission Peak and Neutrality(No.20220013)+1 种基金the National Key Research and Development Program of China(Nos.2023YFE0110800 and 2023YFC3708100)the Fundamental Research Funds for the Central Universities(No.QTPY2024001).
文摘Phthalic acid esters(PAEs)are widely released into the environment due to industrial and agricultural activities.This poses significant risks,not only to crops grown on contaminated soil but also to humans.PAEs enter the human body through the food chain,causing potential health hazards.Endophytic bacteria have demonstrated a significant potential as effective bioremediation agents,with specialized mechanisms of PAEs degradation.Endophytic bacteria such as Rhodococcus,Pseudomonas and Sphingomona recognize root exudates,adhere to and penetrate root surfaces,and ultimately colonize crops.They form symbiotic relationships with crops,obtaining nutrients and habitats from crops,meanwhile,promoting plant growth and health through hormone production,nutrient regulation,and the suppression of pathogenic microorganisms.Furthermore,endophytic bacteria efficiently degrade PAEs in soil-crop systems through synergistic interactions with indigenous rhizosphere microflora and regulatory effects on enzyme activity in crops.Here,we review the role of endophytic bacteria in the bioremediation of PAEs-contaminated crops and soils.In addition,we discuss the scarcity of endophytic bacterial strains with a confirmed ability to degrade PAEs,and underscore the lack of the research on the mechanisms of PAEs degradation by these bacteria.This review also points out that future study should investigate the molecular mechanisms underlying the interaction between endophytic bacteria and PAEs to offer novel insights and solutions for environmental protection and sustainable agricultural development.
基金financial support from the National Natural Science Foundation of China (Nos. 21801087 and 22201089)。
文摘An enantioselective catalytic method for the direct [4 + 1] annulation of yne–allylic acetates with pyrazolones has been realized by a copper-catalyzed remote strategy. A variety of enantioenriched spiropyrazolones are rapidly accessed in high yields with moderate to good enantiocontrol. The facile follow-up transformations highlight its potential utility in the synthesis of diverse spiropyrazolones building blocks.
文摘Background:In today’s context,vegetable oils,commonly used in culinary practices such as frying and baking,are integral to numerous daily dietary choices.Palm oil,a frequently employed vegetable oil,raises concerns surrounding food safety,thus presenting a significant challenge.Methods:This research aims to enhance consumer awareness regarding the potential health risks associated with 3-monochloropropane-1,2-diol(3-MCPD)and glycidyl fatty acid esters(GEs)commonly found in food and edible oil products.The study endeavours to apprise consumers of these health risks through a comprehensive survey.The survey enlisted the participation of 120 respondents within the age bracket of 18 years to those above 36 years(capped at 50 years).Results:Strikingly,a significant proportion,ranging from 88%to 89%,demonstrated a lack of awareness concerning the potential risks associated with 3-MCPD and GEs in food products.Conclusion:This study underscores the urgency of augmenting consumer's awareness levels regarding 3-MCPD and GEs.Furthermore,it promotes a more detailed examination of Malaysian edible oils and food products available in the market to establish an appropriate Tolerable Daily Intake for the Malaysian population.This research contributes to the broader discourse on food safety and public health by highlighting these crucial facets.
文摘Caffeic acid phenethyl ester (CAPE) and sixteen substituted cinnamic acid phenethyl esters were prepared via conventional procedures in order to test their in vitro anticancer activities by either MTT assay or SRB assay on six different human cancer cell lines. The results indicated that in the concentration of 10 μmol·L -1 the lead compound CAPE possessed anticancer activities against human HL 60, Bel 7402, and Hela cell lines, and two other compounds possessed potent anticancer activities against Bel 7402 and Hela cell lines.
基金The National Basic Research Program of China(973Program)(No.2012CB933302)the National Instrumental Research Program(No.2014YQ06077303)+1 种基金the National Natural Science Foundation of China(No.81172720,21307086)Suzhou Science and Technology Department Foundation(No.ZXG201441)
文摘A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.
基金National Nature Science Foundation of China(Nos.52025032,52103144 and 523B2026)for their financial supportsupported by the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(No.GZC20231544)。
文摘As one of the most essential components in photocuring system,photoinitiators(PIs)exert a crucial influence on the properties of the cured product.However,commercially available PIs encounter challenges in simultaneously achieving efficient photoinitiation performance and excellent light absorption properties,significantly limiting their applications in various fields.Here,two bis-chalcones and four corresponding oxime esters(OXEs)were designed and synthesized as highly efficient PIs.Featuring a structure comprising bis-chalcone and two diphenyl sulfides,the conjugated systems in these compounds enhance their light-absorption properties in near-ultraviolet and visible region,effectively.Both the frontier molecular orbital simulations and excited state calculations suggest the contribution of sulfur atoms to electron delocalization and the formation of conjugated structure.Due to the high reactivity of the N–O bond in OXE moiety,the four OXEs exhibit exceptional free radical photoinitiating ability in commercial acrylic monomers/oligomers with LED@365nm as light source.Notably,one of them demonstrates superior performance in the photoinitiation of multifunctional crosslinker,achieving more than 70%conversion within 3 s,coupled with outstanding absorption at 365 nm.These chalcone-based OXEs are considered to exert significant potential in the realm of free radical photocuring.
文摘Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.
基金supported by the National Key R&D Program of China(No.2023YFA1506804)the National Natural Science Foundation of China(Nos.22471110,22171111,22131007 and 22071093)+1 种基金the Science Foundation of Gansu Province of China(No.22JR5RA406)the Fundamental Research Funds for the Central Universities(No.lzujbky-2023-15)。
文摘Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polymers has become an attractive subject.Herein,a new monomer of thiosalicylic methyl glycolide(TSMG)was synthesized using one-pot method and high molecular weight poly(thiosalicylic methyl glycolide)(PTSMG,M_(n) up to 300 kDa)can be obtained via the ring-opening polymerization(ROP)of TSMG.PTSMG exhibits good closed-loop recyclability and hydrolytic degradability,where PTSMG can generate pristine monomers through sublimation thermal depolymerization conditions due to the presence of thiophenol ester bond in the polymer chains,and can be degraded rapidly in aqueous solution,which provides a potential solution to the current plastic pollution problem.
基金Financial support provided by the National High-tech Research and Development Program of China(2014AA022103)。
文摘Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor.The conversion achieved nearly 100%within 5 h under the reaction temperature,the mass ratio of catalyst to fatty acid methyl esters(FAMEs),and isobutanol to FAMEs total molar ratio of 180℃,0.4%(mass),and 5.4:1,respectively.In addition,kinetic model of the transesterification reaction was developed at 150–190℃.The calculated activation energy was 48.93 kJ·mol^(-1).Then,the epoxidation of obtained fatty acid isobutyl esters(FABEs)was conducted in the presence of formic acid and hydrogen peroxide.The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate(DOP)and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters(Ep-FAMEs).The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP.In addition,the extraction resistance and migration stability of Ep-FABEs were better than those of EpFAMEs.Overall,the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer.
基金supported by the National Natural Science Foundation of China (Nos. 21871074 and 21971051)the National Key R&D Program of China (No. 2018YFB1501604)+1 种基金the Fundamental Research Funds for the Central Universities (No. PA2020GDKC0021)the Key Research and Development Program Projects in Anhui Province (No. 201904a07020069)。
文摘An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.
文摘A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)
基金National Natural Science Foundation of China(Grant No.81172943)
文摘To investigate the phytochemical constituents of aboveground parts of Croton tiglium L. （family Euphorbiaceae）, its ingredients were isolated by repeated chromatography on silica gel, Sephadex LH-20, ODS and preparative HPLC. Their structures were identified based on 1D, 2D NMR and mass spectral analysis. A total of 10 phorbol esters were obtained. Among them, compound 1 （12-O-（2-methyl）butyryl-4ct-deoxyphorbol-β-isobutyrate） and compound 10 （20-formyl-4a-deoxyphorbol- β-acetate） were two new compounds, and the other eight were known compounds.
基金supported by the National Basic Research Program of China (No. 2009CB421602)the Water Pollution Control and Treatment Special Project (No.2009ZX07527-001)+1 种基金the State Key Laboratory of Environmental Chemistry and Ecotoxicology (No. KF2010-20)the Special Fund for Public Welfare Industry on Environmental Protection (No. 2009467109)
文摘The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples were collected in June 2010.Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry.Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L,respectively.Fluoranthene,naphthalene,pyrene,phenanthrene,di-2ethylhexyl phthalate,and di-n-butyl phthalate were the most abundant compounds in the samples.The water samples were moderately polluted with benzo[a]pyrene according to China＇s environmental quality standard for surface water.The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake,Wuxi City and the western section of Yangchenghu Lake.Potential sources of pollution at S7 were petroleum combustion and the plastics industry,and at Yangchenghu Lake were petroleum combustion and domestic waste.Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines.There were no obvious sources of pollution for the other water samples.These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs.
文摘Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.
