Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron d...Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron donor because it can be generated from renewable resources,including lignocellulosic biomass and protein wastes.Here,propanol was proven in detail to be an efficient electron donor,enhancing the production of odd medium-chain carboxylates during chain elongation.By exploring various electron acceptors,reactor conditions,and electron donor/electron acceptor mol ratios,our study highlights that acetate is the most suitable electron acceptor for the production of both odd-and even-chain carboxylates.The optimal conditions for propanol-based chain elongation were 30℃ and pH 6,achieving 82.8%selectivity for odd-chain carboxylates.Another critical insight from our work is that a propanol/acetate mol ratio of 1:1 can minimize the inhibitory effect of propanol and maximize the yield of medium-chain carboxylates,with the highest concentration of n-heptanoate reaching 124.5 mmol C/L.This was further illustrated by 16S rRNA amplicon sequencing,which elucidated that the community composition and keystone species in a propanol-based reactor closely resembled that of the ethanol one.The dominant phylum of the propanol-based reactor,Firmicutes showed a significant positive correlation with the concentrations of n-caproate and n-valerate.Additionally,the co-occurrence of Clostridium sensu stricto 12 and Oscillibacter,known as typical chain elongators,was identified within the propanol-based reactor.These findings enhance our understanding of propanolbased chain elongation,offer guiding principles for reactor microbiota assembly,and support efficient odd medium-chain carboxylate production.展开更多
On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient ...On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.展开更多
A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） w...A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） with di-n-butyltin oxide. Compound 1 and complex 2 were characterized by elemental analysis, FTIR spectroscopy, and ~H NMR spectroscopy. The crystal structure of complex 2 was determined by single crystal X-ray diffraction analysis. There are two crystallographic independent molecules in complex 2, and each molecule structure is centro-symmetric and features a central rhombus cyclic Bu4Sn2O2 unit with two exocyclic Sn atoms linked at the O atoms of the four-membered ring. In molecule A, the four Sn atoms are five-coordinated. However, in molecule B, the four Sn atoms have two different coordination geometries, the endocyclic Sn atoms are five-coordinated and the exocyclic Sn atoms are four-coordinated. The dicarboxylate ligands in molecules A and B bridge exocylic or endocyclic tin atoms, forming two macroheterocycles with 26 atoms. Pilot studies have indicated that complex 2 has good anti- bacterial and antitumour activities.展开更多
A simple, precise and rapid liquid chromatography-tandem mass spectrometry （LC-MS/MS） method has been developed and validated for the simultaneous determination of oseltamivir and oseltamivir carboxylate, a neuramin...A simple, precise and rapid liquid chromatography-tandem mass spectrometry （LC-MS/MS） method has been developed and validated for the simultaneous determination of oseltamivir and oseltamivir carboxylate, a neuraminidase inhibitor, using their deuterated analogs as internal standards （ISs）. The method involved solid phase extraction of the analytes and ISs from 200 μL human plasma with no reconstitution and drying steps. The chromatographic separation was achieved on a Symmetry C18 （100 mm × 4.6 mm, 5 μm） column using 10 mM ammonium formate and acetonitrile （30：70, v/v） as the mobile phase in a run time of 2.0 min. Quantitation of analytes and ISs were done by multiple reaction monitoring on a triple quadrupole mass spectrometer in the positive ionization mode. The linearity of the method was established in the concentration range of 0.5-200 ng/mL and 2.0-800 ng/mL for oseltamivir and oseltamivir carboxylate respectively. The mean extraction recovery for oseltamivir （94.4%） and oseltamivir carboxylate （92.7%） from spiked plasma samples was consistent and reproducible. The application of this method was demonstratedby a bioequivalence study in 42 healthy Indian subjects with 75 mg oseltamivir phosphate capsules. The assay reproducibility was established by reanalysis of 151 incurred subject samples.展开更多
Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic dens...Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic densities to investigate their influence on the rheological behavior of cement paste. Three typical rheological models were applied to analyze the rheological properties, including Power-law model, Bingham model as well as Herschel-Buikley model. In addition, the thixotropical performances of cement paste in the presence of PCE with different carboxylic densities were investigated. The results show that the carboxylic density of PCE greatly influences the dispersing performance of PCE superplasticizers. As carboxylic density increases, the dispersing capability of PCE improves, and P（PEG1-AA6） possesses the strongest dispersing capability, the initial fluidity and 1 h fluidity of cement paste are both the highest, and cement paste has the lowest viscosity and the smallest hysteresis loop.展开更多
Free radical co-polymerization was employed to synthesize co-poly carboxylate (PC) su-perplasticizers with different amount of carboxyl and methyl polyethylene glycol (MPEG) side chain. Dispersion ability and retentio...Free radical co-polymerization was employed to synthesize co-poly carboxylate (PC) su-perplasticizers with different amount of carboxyl and methyl polyethylene glycol (MPEG) side chain. Dispersion ability and retention of PC were compared with one another. The results show that increase of side chain is advantageous to dispersion, but it decreases when amount of MPEG is beyond a certain value which is different with the proportion of carboxyl. If the amount of carboxyl increases, the influence of side chain in copolymer on dispersion diminishes. Polyether side chain is advantageous to retention. And the author explained the mechanism of PC using the theory of steric repulsive force.展开更多
Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding sy...Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively.展开更多
Petroleum carboxylate that may be suitable for tertiary oil recovery have been produced inexpensively from the fractions of Daqing crude oil by a two step process.The feed stock was first oxidized in the vapor phase,f...Petroleum carboxylate that may be suitable for tertiary oil recovery have been produced inexpensively from the fractions of Daqing crude oil by a two step process.The feed stock was first oxidized in the vapor phase,followed by reaction of the oxidized products with sodium hydroxide.Dilute solutions of sodium carboxylates were produced and show ultralow(10^(-2)mN/m)interfacial tensions(IFTs)against a variety of hydrocarbons with a wide range of ACN(Alkane Carbon Number).Infrared spectroscopy was used to identify the functional groups in the oxidized and the saponified products.展开更多
Syngas to aromatics(STA)over bifunctional catalysts has attracted much attention in recent years,but the mechanism underlying the formation of aromatics remains controversial.The critical reaction intermediates,carbox...Syngas to aromatics(STA)over bifunctional catalysts has attracted much attention in recent years,but the mechanism underlying the formation of aromatics remains controversial.The critical reaction intermediates,carboxylates,were first identified and then confirmed to essentially promote aromatization in the syngas conversion over a ZnCrAlO_(x)&H-ZSM-5 composite catalyst.This study provides evidence that the carboxylates can be formed during the reactions of formate species and olefins.In addition,it is shown that the carboxylates favor the formation of aromatics over H-ZSM-5 even in the presence of H2.A novel mechanism for the formation of aromatics via the generation and transformation of carboxylate intermediates is proposed,and the transformation of carboxylates to aromatics via methyl-2-cyclopenten-1-one(MCPO)intermediates is indeed likely.A better understanding of the formation mechanism of aromatics would help optimize the composite catalyst.展开更多
A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies（PRWS） and in downstream recirculating cooling water systems（RCWS）using the reclaimed water as makeup. Hydr...A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies（PRWS） and in downstream recirculating cooling water systems（RCWS）using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors（e.g.,gluconate, citrate, tartrate） and zinc sulfate heptahydrate, which provided Zn^2＋ as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate（which could be utilized as a corrosion inhibitor） content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS.Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO4^3- and Zn^2＋ when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.展开更多
Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3＋ coordination centre in europium earboxylates with 1,10-phe...Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3＋ coordination centre in europium earboxylates with 1,10-phenanthroline Eu（RCOO）3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2＇-bipyridine Eu（RCOO）3·Bpy and europium salts Eu（RCOO）3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu（NO2C2H4COO）3·Phen was solved by X-my diffraction method. The predominant influence of steric hindrances on Eu^3＋ coordination centre was observed at increase of the size of aromatic flagment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.展开更多
The IFTs(Interfacial tension)of petroleum carboxylate/alkaline/HPAM(Hydrolyzed polyacrylamide)flooding system with Daing crude oil and the effects of petroleum carboxylate and alkaline on viscoaity of HPAM solution we...The IFTs(Interfacial tension)of petroleum carboxylate/alkaline/HPAM(Hydrolyzed polyacrylamide)flooding system with Daing crude oil and the effects of petroleum carboxylate and alkaline on viscoaity of HPAM solution were studied.There exists remarkable synergism between HPAM and petroleum carboxylate,and the introduction of HPAM into petroleum carboxylate/alka- line system leads the lowering of IFTs against Daqing crude oil,The introduction of petroleum carboxylate into solution of HPAM also leads the decreasing of viscosity,but the extent of viscosity decreasing is much lower than that caused by inorganic salts such as NaCl and CaCl_2.展开更多
Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off volt...Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off voltage of 0.8 V vs.Li＋/Li.potentially improving the safety of the batteries.In addition,good rate performance and long cycle life of these carboxylates make them promising candidates as anode materials for lithium-ion batteries.展开更多
Based on the quantum chemical descriptors and the activities for isoprene polymerization of 12 neodymium carboxylates obtained by authors’earlier work,statistical analysis of data was made and a QSAR model correlatin...Based on the quantum chemical descriptors and the activities for isoprene polymerization of 12 neodymium carboxylates obtained by authors’earlier work,statistical analysis of data was made and a QSAR model correlating the quantum chemical descriptors and the activity was built with the partial least square(PLS)approach.The model is:A=51602εHOMO+6σ+12546,which indicates that the catalytic activity A is positively correlated with the HOMO energyεHOMOand the ligand polarizabilityσ,with the contribution ofσbeing larger,εHOMO smaller.The model’s coefficient of determination r^2=0.96 and that of cross validation q^2=0.94,both being close to 1,which means that its quality is well and its predictive power is strong.Analysis of the modeling process and the resulted QSAR model,together with the interpretation of the model’s mechanism,also shows that the model obtained from this study is valid and reliable.According to the QSAR model,the mechanism of catalyst activity can be interpreted as that neodymium carboxylates with higher HOMO energy and larger ligand polarizability are easier to react with the co-catalysts so as to produce more active and stable centers of catalyst,resulting in a higher activity.展开更多
Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2（5H）-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient tem...Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2（5H）-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient temperature in Et OH. In addition, N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates were synthesised using mentioned catalyst at ambient temperature in Et OH from condensation between formaldehyde, amines, and dialkylacetylenedicarboxylates. This methodology has number of advantages such as： use of green and nonhazardous catalyst, clean work up, short reaction times,high yields and no need to column chromatography.展开更多
The title complex was prepared from self-assembly reaction of La（NO3）3(6H2O, Zn（NO3）2(6H2O, m-cyanobenzoic acid （m-CNC6H4COOH） and pyridine （Py） in refluxing ethanol and its structure was determined by single-...The title complex was prepared from self-assembly reaction of La（NO3）3(6H2O, Zn（NO3）2(6H2O, m-cyanobenzoic acid （m-CNC6H4COOH） and pyridine （Py） in refluxing ethanol and its structure was determined by single-crystal X-ray diffraction. Crystallographic data: C94H62N12La2O22Zn2, Mr = 2120.12, triclinic space group P, a = 13.2219（5）, b = 13.2713（5）, c = 14.1987（6） ?, (???69.156（1）, ( = 84.034（1）, ( = 89.400（1） (, V = 2314.9（2） ?3, Z = 1, Dc = 1.521 g/cm3, F（000） = 1060, ( (MoK（） = 14.94 cm－1, the final R = 0.043 and wR = 0.117 for 6381 unique reflections with I > 2(（I）. Crystal structure determination shows that the neighboring lanthanum（III） and zinc（II） ions are bridged by three bidentate m-cyanobenzonate ligands in the syn-syn fashion to form a pair of dinuclear [LaZn（m-CNC6H4COO）3（Py）（C2H5OH）] subunits, being linked together by two bidentate and two tridentate m-cyanobenzonate groups in the syn-syn and syn-anti modes, respectively, to construct a tetranuclear La-Zn complex [La2Zn2（m-CNC6H4COO）10（Py）2（C2H5OH）2].展开更多
A novel sodium holmium carboxylate compound,namely Na 4 Ho 4 （μ 3-OH） 4 （1,4BDC） 6 ·6.25H 2 O （1,1,4-BDC=1,4-benzenedicarboxylate）,has been solvothermally synthesized and structurally characterized.The str...A novel sodium holmium carboxylate compound,namely Na 4 Ho 4 （μ 3-OH） 4 （1,4BDC） 6 ·6.25H 2 O （1,1,4-BDC=1,4-benzenedicarboxylate）,has been solvothermally synthesized and structurally characterized.The structure features a two-fold interpenetrated three-dimensional open-framework constructed by the [Ho 4 （μ 3-OH） 4 ] 8＋ clusters bridged by 1,4-BDC ligands.The Na ＋ ions and lattice water molecules are located in the channels.The structure is further stabilized by hydrogen-bonding and π-π stacking interactions.The thermal stability of the compound has been investigated via thermogravimetric analysis.展开更多
Precluding the excessive lipoproteins from plasma rapidly and effectively is highly needed for biomedical detection and reducing plasma product scrap in blood donation stations.The current centrifugation procedure is ...Precluding the excessive lipoproteins from plasma rapidly and effectively is highly needed for biomedical detection and reducing plasma product scrap in blood donation stations.The current centrifugation procedure is high-cost and time-consuming.Herein,we fabricated an anionic microfiltration polyethersulfone(PES)membrane modified by interface swelling and implanting of acrylic acid(AA)for screening out large particle lipoprotein chylomicron(CM)and adsorbing cationic very low-density lipoproteins(VLDL).To improve the separation efficiency,a two-stage filtration through carboxylated polyethersulfone microfiltration membranes with the mean pore size of 0.45 and 0.22μm respectively were conducted.Attenuated total reflection Fourier transform infrared technique(ATR-FTIR),water contact angle(WCA),Zeta potential and scanning electron microscope(SEM)were employed to characterize the modified membrane.To test the effectiveness of this membrane,plasma flux and concentration variation of plasma components were examined to study the purification effectiveness.Furthermore,the hemocompatibility of modified membranes was tested to confirm its practicability on bloodcontacting materials.The carboxylated polyethersulfone microfiltration membrane shows its promising potential application to purify chylous plasma.展开更多
One new mixed-ligand coordination polymer,namely[Co2（btc）（bpdc）（0.5）（py）3]n（1）,was hydrothermally synthesized using biphenyl-2,4,4＇-tricarboxylic acid（H3btc） as a main building block,along with two auxili...One new mixed-ligand coordination polymer,namely[Co2（btc）（bpdc）（0.5）（py）3]n（1）,was hydrothermally synthesized using biphenyl-2,4,4＇-tricarboxylic acid（H3btc） as a main building block,along with two auxiliary ligands（H2bpdc = 2,2＇-bipyridine-5,5＇-dicarboxylic acid and py =pyridine）.The product 1 was characterized by IR spectroscopy,elemental,thermogravimetric,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction studies show that compound 1 possesses an intricate 3D metal-organic framework based on tetracobalt（Ⅱ） units.Magnetic susceptibility measurement indicates that compound 1 shows an antiferromagnetic coupling between the Co（Ⅱ） ions.展开更多
Eight tri(2-methyl-2-phznylpropyl) germylpropionates have been synthesized. and their structures were characterized by elemental analysis, IR, multinuclear NMR(H-1,C-13.Sn-119) and MS. The spectroscopic studies reveal...Eight tri(2-methyl-2-phznylpropyl) germylpropionates have been synthesized. and their structures were characterized by elemental analysis, IR, multinuclear NMR(H-1,C-13.Sn-119) and MS. The spectroscopic studies revealed that compounds of this type possess a tetrahedral geometry, which have been expected to have good biological activity.展开更多
基金supported by the National Key R&D Program of China(No.2022YFC2105301)the National Natural Science Foundation of China(No.52270096).
文摘Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron donor because it can be generated from renewable resources,including lignocellulosic biomass and protein wastes.Here,propanol was proven in detail to be an efficient electron donor,enhancing the production of odd medium-chain carboxylates during chain elongation.By exploring various electron acceptors,reactor conditions,and electron donor/electron acceptor mol ratios,our study highlights that acetate is the most suitable electron acceptor for the production of both odd-and even-chain carboxylates.The optimal conditions for propanol-based chain elongation were 30℃ and pH 6,achieving 82.8%selectivity for odd-chain carboxylates.Another critical insight from our work is that a propanol/acetate mol ratio of 1:1 can minimize the inhibitory effect of propanol and maximize the yield of medium-chain carboxylates,with the highest concentration of n-heptanoate reaching 124.5 mmol C/L.This was further illustrated by 16S rRNA amplicon sequencing,which elucidated that the community composition and keystone species in a propanol-based reactor closely resembled that of the ethanol one.The dominant phylum of the propanol-based reactor,Firmicutes showed a significant positive correlation with the concentrations of n-caproate and n-valerate.Additionally,the co-occurrence of Clostridium sensu stricto 12 and Oscillibacter,known as typical chain elongators,was identified within the propanol-based reactor.These findings enhance our understanding of propanolbased chain elongation,offer guiding principles for reactor microbiota assembly,and support efficient odd medium-chain carboxylate production.
基金Funded by the National Natural Science Foundation of China(No.51873167)the Fundamental Research Funds for the Central Universities(WUT:2022-CL-A1-04)。
文摘On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.
基金Supported by the National Natural Science Foundation of China(No.2005038561)Natural Science Foundation of Province,China(Nos.20060571 and 20070406)
文摘A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） with di-n-butyltin oxide. Compound 1 and complex 2 were characterized by elemental analysis, FTIR spectroscopy, and ~H NMR spectroscopy. The crystal structure of complex 2 was determined by single crystal X-ray diffraction analysis. There are two crystallographic independent molecules in complex 2, and each molecule structure is centro-symmetric and features a central rhombus cyclic Bu4Sn2O2 unit with two exocyclic Sn atoms linked at the O atoms of the four-membered ring. In molecule A, the four Sn atoms are five-coordinated. However, in molecule B, the four Sn atoms have two different coordination geometries, the endocyclic Sn atoms are five-coordinated and the exocyclic Sn atoms are four-coordinated. The dicarboxylate ligands in molecules A and B bridge exocylic or endocyclic tin atoms, forming two macroheterocycles with 26 atoms. Pilot studies have indicated that complex 2 has good anti- bacterial and antitumour activities.
文摘A simple, precise and rapid liquid chromatography-tandem mass spectrometry （LC-MS/MS） method has been developed and validated for the simultaneous determination of oseltamivir and oseltamivir carboxylate, a neuraminidase inhibitor, using their deuterated analogs as internal standards （ISs）. The method involved solid phase extraction of the analytes and ISs from 200 μL human plasma with no reconstitution and drying steps. The chromatographic separation was achieved on a Symmetry C18 （100 mm × 4.6 mm, 5 μm） column using 10 mM ammonium formate and acetonitrile （30：70, v/v） as the mobile phase in a run time of 2.0 min. Quantitation of analytes and ISs were done by multiple reaction monitoring on a triple quadrupole mass spectrometer in the positive ionization mode. The linearity of the method was established in the concentration range of 0.5-200 ng/mL and 2.0-800 ng/mL for oseltamivir and oseltamivir carboxylate respectively. The mean extraction recovery for oseltamivir （94.4%） and oseltamivir carboxylate （92.7%） from spiked plasma samples was consistent and reproducible. The application of this method was demonstratedby a bioequivalence study in 42 healthy Indian subjects with 75 mg oseltamivir phosphate capsules. The assay reproducibility was established by reanalysis of 151 incurred subject samples.
基金the State Key Laboratory of Silicate Materials for Architectures(SYSJJ2018-09)the Shaanxi Provincial High Performance Concrete Engineering Laboratory(SHPC201701)
文摘Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic densities to investigate their influence on the rheological behavior of cement paste. Three typical rheological models were applied to analyze the rheological properties, including Power-law model, Bingham model as well as Herschel-Buikley model. In addition, the thixotropical performances of cement paste in the presence of PCE with different carboxylic densities were investigated. The results show that the carboxylic density of PCE greatly influences the dispersing performance of PCE superplasticizers. As carboxylic density increases, the dispersing capability of PCE improves, and P（PEG1-AA6） possesses the strongest dispersing capability, the initial fluidity and 1 h fluidity of cement paste are both the highest, and cement paste has the lowest viscosity and the smallest hysteresis loop.
文摘Free radical co-polymerization was employed to synthesize co-poly carboxylate (PC) su-perplasticizers with different amount of carboxyl and methyl polyethylene glycol (MPEG) side chain. Dispersion ability and retention of PC were compared with one another. The results show that increase of side chain is advantageous to dispersion, but it decreases when amount of MPEG is beyond a certain value which is different with the proportion of carboxyl. If the amount of carboxyl increases, the influence of side chain in copolymer on dispersion diminishes. Polyether side chain is advantageous to retention. And the author explained the mechanism of PC using the theory of steric repulsive force.
文摘Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively.
文摘Petroleum carboxylate that may be suitable for tertiary oil recovery have been produced inexpensively from the fractions of Daqing crude oil by a two step process.The feed stock was first oxidized in the vapor phase,followed by reaction of the oxidized products with sodium hydroxide.Dilute solutions of sodium carboxylates were produced and show ultralow(10^(-2)mN/m)interfacial tensions(IFTs)against a variety of hydrocarbons with a wide range of ACN(Alkane Carbon Number).Infrared spectroscopy was used to identify the functional groups in the oxidized and the saponified products.
文摘Syngas to aromatics(STA)over bifunctional catalysts has attracted much attention in recent years,but the mechanism underlying the formation of aromatics remains controversial.The critical reaction intermediates,carboxylates,were first identified and then confirmed to essentially promote aromatization in the syngas conversion over a ZnCrAlO_(x)&H-ZSM-5 composite catalyst.This study provides evidence that the carboxylates can be formed during the reactions of formate species and olefins.In addition,it is shown that the carboxylates favor the formation of aromatics over H-ZSM-5 even in the presence of H2.A novel mechanism for the formation of aromatics via the generation and transformation of carboxylate intermediates is proposed,and the transformation of carboxylates to aromatics via methyl-2-cyclopenten-1-one(MCPO)intermediates is indeed likely.A better understanding of the formation mechanism of aromatics would help optimize the composite catalyst.
基金supported by the Key Laboratory of Drinking Water Science and Technology, Chinese Academy of Sciences (No. 15Z01KLDWST)the National Natural Science Foundation of China (Nos. 51378491 and 51578533)
文摘A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies（PRWS） and in downstream recirculating cooling water systems（RCWS）using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors（e.g.,gluconate, citrate, tartrate） and zinc sulfate heptahydrate, which provided Zn^2＋ as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate（which could be utilized as a corrosion inhibitor） content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS.Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO4^3- and Zn^2＋ when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.
基金supported by the Russian Foundation for Basic Research (N 08-02-00424-a, N 06-03-32557-a)
文摘Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3＋ coordination centre in europium earboxylates with 1,10-phenanthroline Eu（RCOO）3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2＇-bipyridine Eu（RCOO）3·Bpy and europium salts Eu（RCOO）3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu（NO2C2H4COO）3·Phen was solved by X-my diffraction method. The predominant influence of steric hindrances on Eu^3＋ coordination centre was observed at increase of the size of aromatic flagment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.
文摘The IFTs(Interfacial tension)of petroleum carboxylate/alkaline/HPAM(Hydrolyzed polyacrylamide)flooding system with Daing crude oil and the effects of petroleum carboxylate and alkaline on viscoaity of HPAM solution were studied.There exists remarkable synergism between HPAM and petroleum carboxylate,and the introduction of HPAM into petroleum carboxylate/alka- line system leads the lowering of IFTs against Daqing crude oil,The introduction of petroleum carboxylate into solution of HPAM also leads the decreasing of viscosity,but the extent of viscosity decreasing is much lower than that caused by inorganic salts such as NaCl and CaCl_2.
基金supported by the funding from"863"Project(2011AA11A235)"973"Projects(2010CB833102 and 2012CB932900)+1 种基金NSFC(No.51222210 and 11234013)the 100 Talent Project of the Chinese Academy of Sciences
文摘Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off voltage of 0.8 V vs.Li＋/Li.potentially improving the safety of the batteries.In addition,good rate performance and long cycle life of these carboxylates make them promising candidates as anode materials for lithium-ion batteries.
基金Finacial support from the National Natural Science Foundation of China(21676139)。
文摘Based on the quantum chemical descriptors and the activities for isoprene polymerization of 12 neodymium carboxylates obtained by authors’earlier work,statistical analysis of data was made and a QSAR model correlating the quantum chemical descriptors and the activity was built with the partial least square(PLS)approach.The model is:A=51602εHOMO+6σ+12546,which indicates that the catalytic activity A is positively correlated with the HOMO energyεHOMOand the ligand polarizabilityσ,with the contribution ofσbeing larger,εHOMO smaller.The model’s coefficient of determination r^2=0.96 and that of cross validation q^2=0.94,both being close to 1,which means that its quality is well and its predictive power is strong.Analysis of the modeling process and the resulted QSAR model,together with the interpretation of the model’s mechanism,also shows that the model obtained from this study is valid and reliable.According to the QSAR model,the mechanism of catalyst activity can be interpreted as that neodymium carboxylates with higher HOMO energy and larger ligand polarizability are easier to react with the co-catalysts so as to produce more active and stable centers of catalyst,resulting in a higher activity.
基金financial support from the Research Council of the University of Sistan and Baluchestan,Zahedan, Iran
文摘Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2（5H）-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient temperature in Et OH. In addition, N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates were synthesised using mentioned catalyst at ambient temperature in Et OH from condensation between formaldehyde, amines, and dialkylacetylenedicarboxylates. This methodology has number of advantages such as： use of green and nonhazardous catalyst, clean work up, short reaction times,high yields and no need to column chromatography.
基金the Natural Science Foundation of China, Fujian Province and Chinese Academy of Sciences.
文摘The title complex was prepared from self-assembly reaction of La（NO3）3(6H2O, Zn（NO3）2(6H2O, m-cyanobenzoic acid （m-CNC6H4COOH） and pyridine （Py） in refluxing ethanol and its structure was determined by single-crystal X-ray diffraction. Crystallographic data: C94H62N12La2O22Zn2, Mr = 2120.12, triclinic space group P, a = 13.2219（5）, b = 13.2713（5）, c = 14.1987（6） ?, (???69.156（1）, ( = 84.034（1）, ( = 89.400（1） (, V = 2314.9（2） ?3, Z = 1, Dc = 1.521 g/cm3, F（000） = 1060, ( (MoK（） = 14.94 cm－1, the final R = 0.043 and wR = 0.117 for 6381 unique reflections with I > 2(（I）. Crystal structure determination shows that the neighboring lanthanum（III） and zinc（II） ions are bridged by three bidentate m-cyanobenzonate ligands in the syn-syn fashion to form a pair of dinuclear [LaZn（m-CNC6H4COO）3（Py）（C2H5OH）] subunits, being linked together by two bidentate and two tridentate m-cyanobenzonate groups in the syn-syn and syn-anti modes, respectively, to construct a tetranuclear La-Zn complex [La2Zn2（m-CNC6H4COO）10（Py）2（C2H5OH）2].
基金supported by the NNSFC (Nos. 20771102 and 20873149)NSF of Fujian Province(No. 2008J0174 )973 Program (No. 2006CB932904)
文摘A novel sodium holmium carboxylate compound,namely Na 4 Ho 4 （μ 3-OH） 4 （1,4BDC） 6 ·6.25H 2 O （1,1,4-BDC=1,4-benzenedicarboxylate）,has been solvothermally synthesized and structurally characterized.The structure features a two-fold interpenetrated three-dimensional open-framework constructed by the [Ho 4 （μ 3-OH） 4 ] 8＋ clusters bridged by 1,4-BDC ligands.The Na ＋ ions and lattice water molecules are located in the channels.The structure is further stabilized by hydrogen-bonding and π-π stacking interactions.The thermal stability of the compound has been investigated via thermogravimetric analysis.
基金financially supported by Natural Science Foundation of Ningbo City(2018A610026)Zhejiang Provincial Natural Science Foundation of China for Distinguished Young Scholars(LR20E030002)+1 种基金Ten thousand plan-high level talents special support plan of Zhejiang province,China(ZJWR0108020)Youth Innovation Promotion Association of Chinese Academy of Science(2014258)。
文摘Precluding the excessive lipoproteins from plasma rapidly and effectively is highly needed for biomedical detection and reducing plasma product scrap in blood donation stations.The current centrifugation procedure is high-cost and time-consuming.Herein,we fabricated an anionic microfiltration polyethersulfone(PES)membrane modified by interface swelling and implanting of acrylic acid(AA)for screening out large particle lipoprotein chylomicron(CM)and adsorbing cationic very low-density lipoproteins(VLDL).To improve the separation efficiency,a two-stage filtration through carboxylated polyethersulfone microfiltration membranes with the mean pore size of 0.45 and 0.22μm respectively were conducted.Attenuated total reflection Fourier transform infrared technique(ATR-FTIR),water contact angle(WCA),Zeta potential and scanning electron microscope(SEM)were employed to characterize the modified membrane.To test the effectiveness of this membrane,plasma flux and concentration variation of plasma components were examined to study the purification effectiveness.Furthermore,the hemocompatibility of modified membranes was tested to confirm its practicability on bloodcontacting materials.The carboxylated polyethersulfone microfiltration membrane shows its promising potential application to purify chylous plasma.
基金supported by the Natural Science Foundation of Shanxi Province(No.2013011011-6)the Subject Team of Taiyuan University of Science and Technology
文摘One new mixed-ligand coordination polymer,namely[Co2（btc）（bpdc）（0.5）（py）3]n（1）,was hydrothermally synthesized using biphenyl-2,4,4＇-tricarboxylic acid（H3btc） as a main building block,along with two auxiliary ligands（H2bpdc = 2,2＇-bipyridine-5,5＇-dicarboxylic acid and py =pyridine）.The product 1 was characterized by IR spectroscopy,elemental,thermogravimetric,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction studies show that compound 1 possesses an intricate 3D metal-organic framework based on tetracobalt（Ⅱ） units.Magnetic susceptibility measurement indicates that compound 1 shows an antiferromagnetic coupling between the Co（Ⅱ） ions.
文摘Eight tri(2-methyl-2-phznylpropyl) germylpropionates have been synthesized. and their structures were characterized by elemental analysis, IR, multinuclear NMR(H-1,C-13.Sn-119) and MS. The spectroscopic studies revealed that compounds of this type possess a tetrahedral geometry, which have been expected to have good biological activity.
