The title compound, acetic acid-3,5-diacetoxy-2-acetoxymethyl-6-（4-quinoxalin- 2-yl-phenoxy）-tetrahydro-pyran-4-yl-ester 8 （C28H28N2O10, Mr = 552.54）, has been synthesized and its crystal structure was determined ...The title compound, acetic acid-3,5-diacetoxy-2-acetoxymethyl-6-（4-quinoxalin- 2-yl-phenoxy）-tetrahydro-pyran-4-yl-ester 8 （C28H28N2O10, Mr = 552.54）, has been synthesized and its crystal structure was determined by X-ray diffraction analysis. It crystallizes in monoclinic, space group P21, a = 10.060（8）, b = 5.648（4）, c = 24.11（2）A, β = 91.078（10）°, Z = 2, V= 1369.9（19）A^3, Dc = 1.339 g/cm^3,μ（MoKa） = 1.03 cm^-1, F（000） = 580.00, T =. 193.1 Kx-9 θmax = 25.03, （△/σ）max = 0.0000, Flack = -0.0（24）, the final R = 0.0680 and wR = 0.140 （w = 1/[0.0016Fo^2 ＋ 1.00000（Fo^2）]/（4Fo^2）） for 3126 observed reflections （1 〉 20（/））. The pyranoid ring adopts chair conformation in the sugar moiety, and all of the acetyl groups are in the e bond of the pyranoid ring, so the sugar moiety is very stable.展开更多
Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with differ...Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the product distributions in the integral and the differential reactors. The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4C12/C2H4 mole ratio=0.03) to the reactants.展开更多
A novel Zn（Ⅱ） complex, [ZnL2（H2O）4]·H2O（1, HL = 2-（nicotinoyloxy）acetic acid）, was synthesized using Zn（OAc）2·2H2O and 2-（nicotinoyloxy）acetic acid as raw materials. Its structure has been eluci...A novel Zn（Ⅱ） complex, [ZnL2（H2O）4]·H2O（1, HL = 2-（nicotinoyloxy）acetic acid）, was synthesized using Zn（OAc）2·2H2O and 2-（nicotinoyloxy）acetic acid as raw materials. Its structure has been elucidated by elemental analysis, IR and single-crystal X-ray diffraction. The structural analysis revealed that complex 1 crystallizes in triclinic, space group P1 and the Zn（Ⅱ） atom is six-coordinated with two N atoms from two different 2-（nicotinoyloxy）acetate anion ligands and four O atoms from coordinated water molecules. Complex 1 forms a 3D network structure by O–H···O hydrogen bonds. The antitumor activities of 2-（nicotinoyloxy）acetic acid ligand and its Zn（Ⅱ） complex were evaluated against human lung adenocarcinoma A549 cells, human hepatoma SMMC-7721 cells and human colon carcinoma Wi Dr cells.展开更多
A new binuclear Zn^Ⅱ coordination complex,Zn2（bta）（phen）2（Cl）3（1,Hbta = 2-（1Hbenzotriazol-1-yl）acetic acid and phen = 1,10-phenanthroline）,has been synthesized and characterized by single-crystal X-ray diff...A new binuclear Zn^Ⅱ coordination complex,Zn2（bta）（phen）2（Cl）3（1,Hbta = 2-（1Hbenzotriazol-1-yl）acetic acid and phen = 1,10-phenanthroline）,has been synthesized and characterized by single-crystal X-ray diffraction,IR spectroscopy,elemental,and photoluminescent analysis.Complex 1 crystallizes in triclinic system,space group P1 with a = 9.3040（19）,b = 10.694（2）,c =16.841（3） A°,α = 101.18（3）,β = 105.77（3）,γ = 91.72（3）°,V= 1575.8（5） A°3,C（32）H（22）Zn2Cl3N7O2,Mr =773.66,Dc = 1.631 g/cm^3,Z = 2,F（000） = 780,μ = 1.820 mm^-1,the final R = 0.1238 and wR =0.1131.X-ray diffraction analyses indicate that 1 displays two crystallographic independent Zn^Ⅱmetal centers with a distorted tetragonal pyramidal（ZnN4O） and a tetrahedral（ZnNCl3） geometries,respectively.The phen serves as a common N,N＇-bidentate ligand,and the bta^- as a unique N,O-bridged ligand in 1.In the crystal,1 forms a stable 3D supramolecular architecture by trifurcated hydrogen bonding C-H…C1 interactions and C-H…π,π…π stacking.1 showed photo-electric conversion properties.展开更多
Eight rare earth metal （ Ⅲ ） complexes with 2- （ （（4,6-dimethyl）-2-pyrimidinyl） thio）-acetic acid, LnL3· n H2O [HL = 2-（（（4,6-dimethyl）-2-pyrimidinyl）thio）-acetic acid; Ln = La, Ce, Pr, Nd, Sm Eu, ...Eight rare earth metal （ Ⅲ ） complexes with 2- （ （（4,6-dimethyl）-2-pyrimidinyl） thio）-acetic acid, LnL3· n H2O [HL = 2-（（（4,6-dimethyl）-2-pyrimidinyl）thio）-acetic acid; Ln = La, Ce, Pr, Nd, Sm Eu, Gd, Tb; n = 4 or 5], were prepared and characterized by elemental analysis, complexometric titration, thermal analysis, conductivity, IR and ^1H- NMR. The results reveal that carboxyl group of the hgand coordinates with rare earth ions in bidentate mode after deprotonated. The water molecules exist as crystal water in the complexes. The anti-tumour activities of HL and some complexes were tested by both the MTT and SRB methods. The results show that the suppression ratios of some complexes against the tested tumour cells （HL-60 human leukemia cell lines, BGC-823 human gastric carcinoma cell lines, hela human cervix adenocarcinoma cell lines and Bel-7402 human hepatic carcinoma cell lines） are superior to HL.展开更多
A new series of compounds, 2-（benzodioxol-2-yl）acetic acids, have been synthesized. Their structures were confirmed by MS and 1H-NMR. The preliminary pharmacological screening showed that these compounds exhibited p...A new series of compounds, 2-（benzodioxol-2-yl）acetic acids, have been synthesized. Their structures were confirmed by MS and 1H-NMR. The preliminary pharmacological screening showed that these compounds exhibited potent human PPARδ agonist activities.展开更多
The reaction mechanism of o-aminophenol, acetic acid and phosphorus oxytrichloride in one-pot to form 2-methyl benzoxazole was studied by density functional theory. The geometries of the reactants, transition states, ...The reaction mechanism of o-aminophenol, acetic acid and phosphorus oxytrichloride in one-pot to form 2-methyl benzoxazole was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the GGA/PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Two possible reaction pathways were investigated in this study. The result indicates that the reaction Re→TS1→IM1→TSA2→IMA2→TSA3→IMA3→TSA4→IMA4→TSA5→P2 is the main pathway, the activation energy of which is the lowest. Re→TS1→IM1 is the rate-limiting step, with the activation energy being 221.54 kJ·mol;and the reaction heat being 10.06 kJ·mol;. The dominant product predicted theoretically is in agreement with the experiment results.展开更多
A new compound 2-（3,5-di-tert-butyl-2-hydroxyphenyl）-2-（3,4-dimethylphenyl） acetic acid dimethylamine salt （[NH2（CH3）2][C24H31O3]） was synthesized and structurally determined. It is of monoclinic system, space...A new compound 2-（3,5-di-tert-butyl-2-hydroxyphenyl）-2-（3,4-dimethylphenyl） acetic acid dimethylamine salt （[NH2（CH3）2][C24H31O3]） was synthesized and structurally determined. It is of monoclinic system, space group P21/c with a = 14.731（2）, b = 10.1185（10）, c = 17.065（2） A^°, β = 98.293（10）° ,Z = 4, V = 2517.0（6）A^°^3, Dc = 1.091 g/cm^3, F（000） = 904 and Mr= 413.58. The dihedral angle defined by two benzene rings is 98.23°.展开更多
The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional....The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern.展开更多
The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programm...The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.展开更多
Background:In recent years,nitrooxy compounds have been identified as promising inhibitors of methanogenesis in ruminants.However,when animals receive a nitrooxy compound,a high portion of the spared hydrogen is eruct...Background:In recent years,nitrooxy compounds have been identified as promising inhibitors of methanogenesis in ruminants.However,when animals receive a nitrooxy compound,a high portion of the spared hydrogen is eructated as gas,which partly offsets the energy savings of CH4mitigation.The objective of the present study was to evaluate the long-term and combined effects of supplementation with N-[2-(nitrooxy)ethyl]-3-pyridinecarboxamide(NPD),a methanogenesis inhibitor,and fumaric acid(FUM),a hydrogen sink,on enteric CH4production,rumen fermentation,bacterial populations,apparent nutrient digestibility,and lactation performance of dairy goats.Results:Twenty-four primiparous dairy goats were used in a randomized complete block design with a 2×2factorial arrangement of treatments:supplementation without or with FUM(32 g/d)or NPD(0.5 g/d).All samples were collected every 3 weeks during a 12-week feeding experiment.Both FUM and NPD supplementation persistently inhibited CH4yield(L/kg DMI,by 18.8%and 18.1%,respectively)without negative influence on DMI or apparent nutrient digestibility.When supplemented in combination,no additive CH4suppression was observed.FUM showed greater responses in increasing the molar proportion of propionate when supplemented with NPD than supplemented alone(by 10.2%vs.4.4%).The rumen microbiota structure in the animals receiving FUM was different from that of the other animals,particularly changed the structure of phylum Firmicutes.Daily milk production and serum total antioxidant capacity were improved by NPD,but the contents of milk fat and protein were decreased,probably due to the bioactivity of absorbed NPD on body metabolism.Conclusions:Supplementing NPD and FUM in combination is a promising way to persistently inhibit CH4emissions with a higher rumen propionate proportion.However,the side effects of this nitrooxy compound on animals and its residues in animal products need further evaluation before it can be used as an animal feed additive.展开更多
A novel copper（Ⅱ） complex with tert-butyl 2-[N-（tert-butyloxycarbonylmethyl）-2-picolyamino]acetate（ampy） was synthesized and structurally characterized by elemental analysis, FT-IR spectrum, electrospray ioniza...A novel copper（Ⅱ） complex with tert-butyl 2-[N-（tert-butyloxycarbonylmethyl）-2-picolyamino]acetate（ampy） was synthesized and structurally characterized by elemental analysis, FT-IR spectrum, electrospray ionization-mass spectrometry, UV-vis spectrum and single-crystal X-ray diffraction, respectively. A mononuclear copper（II） complex with ampy, [Cu（ampy）Cl2]（1）, was formed irrespective of the metal-to-ligand molar ratios（[Cu2＋]：[ampy] = 0.5：1, 1：1, and 2：1） as a single product. Complex 1 crystallizes in the orthorhombic system, space group Pbca with a = 12.343（2）, b = 18.928（3）, c = 20.058（4） A, V = 4686.1（14） A3, Z = 8, Dc = 1.3349（4） g/cm3, F（000） = 1920, S = 1.016, R = 0.0693 and w R = 0.1721 for 3151 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that the central copper（II） ion is bound by pyridyl N, tertiary amine N and carbonyl O atoms of the quadridentate ampy as well as two Cl anions, constructing a slightly distorted octahedral geometry. Complex 1 further constructs a stable 3D supramolecular architecture by intermolecular C–H…Cl hydrogen bonds. In addition, the molecular geometry was calculated by density functional theory（DFT/B3LYP） method with the basis sets（6-31＋G（d,p） for H, C, N, O and Cl atoms, and LANL2 DZ for Cu atom, respectively）. The calculated results show that the optimized geometrical parameters are in good agreement with the experimental data. Natural bond orbital（NBO） analysis and frontier molecular orbitals（FMOs） analysis were investigated at the same level.展开更多
Direct oxidation of ethene to acetic acid over Pd-SiW12/SiO2 catalysts prepared by several methods was studied. A better method for reducing palladium composition of the catalysts was found. Acetic acid was obtained w...Direct oxidation of ethene to acetic acid over Pd-SiW12/SiO2 catalysts prepared by several methods was studied. A better method for reducing palladium composition of the catalysts was found. Acetic acid was obtained with selectivity of 82.7% and once-through space time yield (STY) of 257.4 g/h .L.展开更多
The reaction mechanisms of intermolecular cleavage reaction of N-（2-hydroxyphenyl）-phthalamic acid were studied via the density functional theory（DFT）. All geometries of the reactant, transition states, and produc...The reaction mechanisms of intermolecular cleavage reaction of N-（2-hydroxyphenyl）-phthalamic acid were studied via the density functional theory（DFT）. All geometries of the reactant, transition states, and products were optimized at the B3LYP/6-31G（d, p） level. Vibration analysis was carried out to confirm its identity as transitions＇ structure, and the intrinsic reaction coordinate method（IRC） was used to search the minimum energy path. Two possible reaction channels are reported in this article. The calculated results indicate that O-cyclization reaction channel has the lower activation barrier, and therefore, it occurs more easier than the other.展开更多
基金This project was supported by the Key Laboratory of Organic Synthesis of Jiangsu Province
文摘The title compound, acetic acid-3,5-diacetoxy-2-acetoxymethyl-6-（4-quinoxalin- 2-yl-phenoxy）-tetrahydro-pyran-4-yl-ester 8 （C28H28N2O10, Mr = 552.54）, has been synthesized and its crystal structure was determined by X-ray diffraction analysis. It crystallizes in monoclinic, space group P21, a = 10.060（8）, b = 5.648（4）, c = 24.11（2）A, β = 91.078（10）°, Z = 2, V= 1369.9（19）A^3, Dc = 1.339 g/cm^3,μ（MoKa） = 1.03 cm^-1, F（000） = 580.00, T =. 193.1 Kx-9 θmax = 25.03, （△/σ）max = 0.0000, Flack = -0.0（24）, the final R = 0.0680 and wR = 0.140 （w = 1/[0.0016Fo^2 ＋ 1.00000（Fo^2）]/（4Fo^2）） for 3126 observed reflections （1 〉 20（/））. The pyranoid ring adopts chair conformation in the sugar moiety, and all of the acetyl groups are in the e bond of the pyranoid ring, so the sugar moiety is very stable.
文摘Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the product distributions in the integral and the differential reactors. The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4C12/C2H4 mole ratio=0.03) to the reactants.
基金supported by the National Natural Science Foundation of China(No.21171132)the Project of Shandong Province Higher Educational Science and Technology Program(J14LC01)Science Foundation of Weifang
文摘A novel Zn（Ⅱ） complex, [ZnL2（H2O）4]·H2O（1, HL = 2-（nicotinoyloxy）acetic acid）, was synthesized using Zn（OAc）2·2H2O and 2-（nicotinoyloxy）acetic acid as raw materials. Its structure has been elucidated by elemental analysis, IR and single-crystal X-ray diffraction. The structural analysis revealed that complex 1 crystallizes in triclinic, space group P1 and the Zn（Ⅱ） atom is six-coordinated with two N atoms from two different 2-（nicotinoyloxy）acetate anion ligands and four O atoms from coordinated water molecules. Complex 1 forms a 3D network structure by O–H···O hydrogen bonds. The antitumor activities of 2-（nicotinoyloxy）acetic acid ligand and its Zn（Ⅱ） complex were evaluated against human lung adenocarcinoma A549 cells, human hepatoma SMMC-7721 cells and human colon carcinoma Wi Dr cells.
基金supported by Guangxi Provincial Department of Education(No.KY2015ZD130)the Natural Science Foundation of Guangxi Province(No.2013GXNSFBA019030)the financial support from the Natural Science Foundation of Qinzhou University(No.2014PY-GJ05)
文摘A new binuclear Zn^Ⅱ coordination complex,Zn2（bta）（phen）2（Cl）3（1,Hbta = 2-（1Hbenzotriazol-1-yl）acetic acid and phen = 1,10-phenanthroline）,has been synthesized and characterized by single-crystal X-ray diffraction,IR spectroscopy,elemental,and photoluminescent analysis.Complex 1 crystallizes in triclinic system,space group P1 with a = 9.3040（19）,b = 10.694（2）,c =16.841（3） A°,α = 101.18（3）,β = 105.77（3）,γ = 91.72（3）°,V= 1575.8（5） A°3,C（32）H（22）Zn2Cl3N7O2,Mr =773.66,Dc = 1.631 g/cm^3,Z = 2,F（000） = 780,μ = 1.820 mm^-1,the final R = 0.1238 and wR =0.1131.X-ray diffraction analyses indicate that 1 displays two crystallographic independent Zn^Ⅱmetal centers with a distorted tetragonal pyramidal（ZnN4O） and a tetrahedral（ZnNCl3） geometries,respectively.The phen serves as a common N,N＇-bidentate ligand,and the bta^- as a unique N,O-bridged ligand in 1.In the crystal,1 forms a stable 3D supramolecular architecture by trifurcated hydrogen bonding C-H…C1 interactions and C-H…π,π…π stacking.1 showed photo-electric conversion properties.
文摘Eight rare earth metal （ Ⅲ ） complexes with 2- （ （（4,6-dimethyl）-2-pyrimidinyl） thio）-acetic acid, LnL3· n H2O [HL = 2-（（（4,6-dimethyl）-2-pyrimidinyl）thio）-acetic acid; Ln = La, Ce, Pr, Nd, Sm Eu, Gd, Tb; n = 4 or 5], were prepared and characterized by elemental analysis, complexometric titration, thermal analysis, conductivity, IR and ^1H- NMR. The results reveal that carboxyl group of the hgand coordinates with rare earth ions in bidentate mode after deprotonated. The water molecules exist as crystal water in the complexes. The anti-tumour activities of HL and some complexes were tested by both the MTT and SRB methods. The results show that the suppression ratios of some complexes against the tested tumour cells （HL-60 human leukemia cell lines, BGC-823 human gastric carcinoma cell lines, hela human cervix adenocarcinoma cell lines and Bel-7402 human hepatic carcinoma cell lines） are superior to HL.
基金supported by the National High Technology Research and Development Program of China(863 project:2003AA235010)the National Natural Science Foundation of China(No.30472092).
文摘A new series of compounds, 2-（benzodioxol-2-yl）acetic acids, have been synthesized. Their structures were confirmed by MS and 1H-NMR. The preliminary pharmacological screening showed that these compounds exhibited potent human PPARδ agonist activities.
基金Supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJ1601215)the Ministry of Education "Chunhui Plan"(Z2016177)
文摘The reaction mechanism of o-aminophenol, acetic acid and phosphorus oxytrichloride in one-pot to form 2-methyl benzoxazole was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the GGA/PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Two possible reaction pathways were investigated in this study. The result indicates that the reaction Re→TS1→IM1→TSA2→IMA2→TSA3→IMA3→TSA4→IMA4→TSA5→P2 is the main pathway, the activation energy of which is the lowest. Re→TS1→IM1 is the rate-limiting step, with the activation energy being 221.54 kJ·mol;and the reaction heat being 10.06 kJ·mol;. The dominant product predicted theoretically is in agreement with the experiment results.
基金supported by the Technology Risk Innovation Fund of PetroChina Company Ltd.
文摘A new compound 2-（3,5-di-tert-butyl-2-hydroxyphenyl）-2-（3,4-dimethylphenyl） acetic acid dimethylamine salt （[NH2（CH3）2][C24H31O3]） was synthesized and structurally determined. It is of monoclinic system, space group P21/c with a = 14.731（2）, b = 10.1185（10）, c = 17.065（2） A^°, β = 98.293（10）° ,Z = 4, V = 2517.0（6）A^°^3, Dc = 1.091 g/cm^3, F（000） = 904 and Mr= 413.58. The dihedral angle defined by two benzene rings is 98.23°.
文摘The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern.
文摘The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.
基金supported by the National Natural Science Foundation of China(award number:31902126)the Science&Technological Project of Shaanxi Province,China(award number:2017TSCXL-NY-04-01)。
文摘Background:In recent years,nitrooxy compounds have been identified as promising inhibitors of methanogenesis in ruminants.However,when animals receive a nitrooxy compound,a high portion of the spared hydrogen is eructated as gas,which partly offsets the energy savings of CH4mitigation.The objective of the present study was to evaluate the long-term and combined effects of supplementation with N-[2-(nitrooxy)ethyl]-3-pyridinecarboxamide(NPD),a methanogenesis inhibitor,and fumaric acid(FUM),a hydrogen sink,on enteric CH4production,rumen fermentation,bacterial populations,apparent nutrient digestibility,and lactation performance of dairy goats.Results:Twenty-four primiparous dairy goats were used in a randomized complete block design with a 2×2factorial arrangement of treatments:supplementation without or with FUM(32 g/d)or NPD(0.5 g/d).All samples were collected every 3 weeks during a 12-week feeding experiment.Both FUM and NPD supplementation persistently inhibited CH4yield(L/kg DMI,by 18.8%and 18.1%,respectively)without negative influence on DMI or apparent nutrient digestibility.When supplemented in combination,no additive CH4suppression was observed.FUM showed greater responses in increasing the molar proportion of propionate when supplemented with NPD than supplemented alone(by 10.2%vs.4.4%).The rumen microbiota structure in the animals receiving FUM was different from that of the other animals,particularly changed the structure of phylum Firmicutes.Daily milk production and serum total antioxidant capacity were improved by NPD,but the contents of milk fat and protein were decreased,probably due to the bioactivity of absorbed NPD on body metabolism.Conclusions:Supplementing NPD and FUM in combination is a promising way to persistently inhibit CH4emissions with a higher rumen propionate proportion.However,the side effects of this nitrooxy compound on animals and its residues in animal products need further evaluation before it can be used as an animal feed additive.
基金supported by the National Basic Research Program of China(No.2014CB643401)the National Natural Science Foundation of China(Nos.51134007 and 51474256)
文摘A novel copper（Ⅱ） complex with tert-butyl 2-[N-（tert-butyloxycarbonylmethyl）-2-picolyamino]acetate（ampy） was synthesized and structurally characterized by elemental analysis, FT-IR spectrum, electrospray ionization-mass spectrometry, UV-vis spectrum and single-crystal X-ray diffraction, respectively. A mononuclear copper（II） complex with ampy, [Cu（ampy）Cl2]（1）, was formed irrespective of the metal-to-ligand molar ratios（[Cu2＋]：[ampy] = 0.5：1, 1：1, and 2：1） as a single product. Complex 1 crystallizes in the orthorhombic system, space group Pbca with a = 12.343（2）, b = 18.928（3）, c = 20.058（4） A, V = 4686.1（14） A3, Z = 8, Dc = 1.3349（4） g/cm3, F（000） = 1920, S = 1.016, R = 0.0693 and w R = 0.1721 for 3151 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that the central copper（II） ion is bound by pyridyl N, tertiary amine N and carbonyl O atoms of the quadridentate ampy as well as two Cl anions, constructing a slightly distorted octahedral geometry. Complex 1 further constructs a stable 3D supramolecular architecture by intermolecular C–H…Cl hydrogen bonds. In addition, the molecular geometry was calculated by density functional theory（DFT/B3LYP） method with the basis sets（6-31＋G（d,p） for H, C, N, O and Cl atoms, and LANL2 DZ for Cu atom, respectively）. The calculated results show that the optimized geometrical parameters are in good agreement with the experimental data. Natural bond orbital（NBO） analysis and frontier molecular orbitals（FMOs） analysis were investigated at the same level.
文摘Direct oxidation of ethene to acetic acid over Pd-SiW12/SiO2 catalysts prepared by several methods was studied. A better method for reducing palladium composition of the catalysts was found. Acetic acid was obtained with selectivity of 82.7% and once-through space time yield (STY) of 257.4 g/h .L.
基金Supported by the National Natural Science Foundation of China(No.20672104)
文摘The reaction mechanisms of intermolecular cleavage reaction of N-（2-hydroxyphenyl）-phthalamic acid were studied via the density functional theory（DFT）. All geometries of the reactant, transition states, and products were optimized at the B3LYP/6-31G（d, p） level. Vibration analysis was carried out to confirm its identity as transitions＇ structure, and the intrinsic reaction coordinate method（IRC） was used to search the minimum energy path. Two possible reaction channels are reported in this article. The calculated results indicate that O-cyclization reaction channel has the lower activation barrier, and therefore, it occurs more easier than the other.
