Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reac...Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.展开更多
The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bar...The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...展开更多
The phase and microstructure properties of laser cladding single phase NiAl coating at elevated temperature of 800 °C were investigated by means of XRD,SEM,and HRTEM.It was found that Ni3Al phase with a fine equi...The phase and microstructure properties of laser cladding single phase NiAl coating at elevated temperature of 800 °C were investigated by means of XRD,SEM,and HRTEM.It was found that Ni3Al phase with a fine equiaxial microstructure precipitated along NiAl grain boundaries via the solid-state diffusion of Ni atoms during heating process.NiAl and Ni3Al phases have a common<110>zone axis.The phase and microstructure evolutions of NiAl during heating process can acquire well understand the diffusion behavior of laser cladding NiAl intermetallic compound coating and provide better guidance on its production and practical use.展开更多
An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The...An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.展开更多
The title compounds 3a - 3n were prepared with high yields via the reaction of 4-methylphenoxyacetyl chloride with various substituted aromatic ammes under the condition of liquidliquid phase transfer catalysis using...The title compounds 3a - 3n were prepared with high yields via the reaction of 4-methylphenoxyacetyl chloride with various substituted aromatic ammes under the condition of liquidliquid phase transfer catalysis using polyethylene glycol-400 as catalyst.展开更多
Solid liquid extraction of copper ion (I) with 2, 9-dimethyl-1, 10-phenanthroline (neo-cuproine, DMP) into molten naphthalene followed by chloroform spectrophotometric determination has been studied experimentally. Th...Solid liquid extraction of copper ion (I) with 2, 9-dimethyl-1, 10-phenanthroline (neo-cuproine, DMP) into molten naphthalene followed by chloroform spectrophotometric determination has been studied experimentally. The ternary complex Cu(I)-DMP-ClO4 was extracted quantitatively into molten naphthalene in the range of pH from 5 to 6 at 85 C-. Absorbance was spectrophotometrically determined at 459 nm against the reagent blank after the solid naphthalene layer was anhydrously dissolved in chloroform. Beer's law is obeyed over a concentration range of 0.5-70 mug/mL. The molar absorptivity and Sandell's sensitivity are 1.0x10(4) L/(mol(.)cm) and 0.0099 mug(.)cm(2) respectively. In addition, the various conditions on determination and the interference of coexisted ions were discussed, and the method was applied to the determination of copper ion both in tea samples and cadmium sulfate reagents. The results are in good agreement with those obtained by ICP AES method.展开更多
The oxidation of hydroquinone(QH_2) was investigated for the first time at liquid/liquid(L/L) interface by scanning electrochemical microscopy(SECM).In this study,electron transfer(ET) from QH_2 in aqueous to ferrocen...The oxidation of hydroquinone(QH_2) was investigated for the first time at liquid/liquid(L/L) interface by scanning electrochemical microscopy(SECM).In this study,electron transfer(ET) from QH_2 in aqueous to ferrocene(Fc) in nitrobenzene (NB) was probed.The apparent heterogeneous rate constants for ET reactions were obtained by fitting the experimental approach curves to the theoretical values.The results showed that the rate constants for oxidation reaction of QH_2 were sensitive to the changes of the dri...展开更多
Comparison in electron transfer(ET) processes from decamethyferrocene(DMFe) in nitrobenzene(NB) to ferric ion in aqueous phase was investigated for the first time by the scanning electrochemical microscopy(SECM).As co...Comparison in electron transfer(ET) processes from decamethyferrocene(DMFe) in nitrobenzene(NB) to ferric ion in aqueous phase was investigated for the first time by the scanning electrochemical microscopy(SECM).As compared with the system of Fe(CN)_6^(3-)-DMFe,the ET rate obtained from Fe^(3+)-DMFe was lower in spite of larger driving force,which may arise from the effect of reorganization energy.Otherwise,the effect of common ion on rate constants was also probed and results suggested additional complexit...展开更多
A new triterpenoid glycoside, named decaisoside F. has been isolated from Decaisnea faresii. Its structure was determined on basis of chi mical method, FAB-MS. homonuclear and heteronuclear correlation esperiments. in...A new triterpenoid glycoside, named decaisoside F. has been isolated from Decaisnea faresii. Its structure was determined on basis of chi mical method, FAB-MS. homonuclear and heteronuclear correlation esperiments. including H-1--(HCOSY)-H-1. H-1--C-13 COSY, TOSCY, HMBC and NOESY techniques to be 3-O-beta-D- xylopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-Larabinopyranosyl) hederagenin 28-O-beta-D-xylopyranosyl (1-->4)-beta-D-glucopyrancrsyl (1-->6)-beta-D-glucopyranoside.展开更多
In this work,by a combination of controlled ring-opening polymerization(CROP) and click reaction,we reported a facile and useful method to synthesize linear poly(ε-caprolactone) at attapulgite nanocomposites with wel...In this work,by a combination of controlled ring-opening polymerization(CROP) and click reaction,we reported a facile and useful method to synthesize linear poly(ε-caprolactone) at attapulgite nanocomposites with well-defined structures.For this,first, the chlorine terminated attapulgite was prepared by the self-assembly of 3-chloropropyltrimethoxysiIane from the surfaces of attapulgite.And then,the terminal chlorines of modified attapulgite were substituted with azido groups.As the second step,linear propa...展开更多
Water-insoluble carboxyl-containing starch graft polymers were prepared. Residual metal ion concentrations in solutions treated with the insoluble starch graft polymers were measured in different pH. The mechanism of ...Water-insoluble carboxyl-containing starch graft polymers were prepared. Residual metal ion concentrations in solutions treated with the insoluble starch graft polymers were measured in different pH. The mechanism of removing heavy metals from aqueous solutions with the carboxylated starchs was described.展开更多
Three new diterpene alkaloids, transconitine A, B and C were isolated from the roots of Aconitum transsectum Diels, and their structures were elucidated by spectral means.
Hypersensitivity of the ternary complexes Ln(beta-dik)(4)HMQ(where Ln=Nd, Ho, Er, beta-dik=acetylacetonate(AA), dibenzoylmethanate(DBM) and MQ=4-methylquinoline) in acetone solution is studied based on the dynamic cou...Hypersensitivity of the ternary complexes Ln(beta-dik)(4)HMQ(where Ln=Nd, Ho, Er, beta-dik=acetylacetonate(AA), dibenzoylmethanate(DBM) and MQ=4-methylquinoline) in acetone solution is studied based on the dynamic coupling model. The structures of these complexes in solution are deduced. Their coordination polyhedrons are all distorted square antiprism. Neodymium complexes have D-2 symmetry, while holmium and erbium complexes have exact D-2d symmetry.展开更多
基金supported by the Natural Science Foundation of China(No.20272047,20572086)the Gansu Natural Science Foundation of China(No.0308RJZA-100)Key Laboratory of Eco-Environment-Related Polymer Material(Northwest Normal University),Ministry of the Education of China
文摘Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.
基金the Project of Natural Science Foundation of Gansu Province of their financial supports(No. 096RJZA117)
文摘The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...
基金National Natural Science Foundation of China(Grant Nos.50705094,51045004)Innovative Group Foundation from NSFC(Grant No 50421502)National 973 Project(2007 CB607601)
文摘The phase and microstructure properties of laser cladding single phase NiAl coating at elevated temperature of 800 °C were investigated by means of XRD,SEM,and HRTEM.It was found that Ni3Al phase with a fine equiaxial microstructure precipitated along NiAl grain boundaries via the solid-state diffusion of Ni atoms during heating process.NiAl and Ni3Al phases have a common<110>zone axis.The phase and microstructure evolutions of NiAl during heating process can acquire well understand the diffusion behavior of laser cladding NiAl intermetallic compound coating and provide better guidance on its production and practical use.
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061- A25-019)the Scientific Research fund of Gansu Provincial Education Department(No.0601-25)
文摘An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.
文摘The title compounds 3a - 3n were prepared with high yields via the reaction of 4-methylphenoxyacetyl chloride with various substituted aromatic ammes under the condition of liquidliquid phase transfer catalysis using polyethylene glycol-400 as catalyst.
基金This research was financially supported by the project KJCXGC-01 of Northwest Normal University, China.
文摘Solid liquid extraction of copper ion (I) with 2, 9-dimethyl-1, 10-phenanthroline (neo-cuproine, DMP) into molten naphthalene followed by chloroform spectrophotometric determination has been studied experimentally. The ternary complex Cu(I)-DMP-ClO4 was extracted quantitatively into molten naphthalene in the range of pH from 5 to 6 at 85 C-. Absorbance was spectrophotometrically determined at 459 nm against the reagent blank after the solid naphthalene layer was anhydrously dissolved in chloroform. Beer's law is obeyed over a concentration range of 0.5-70 mug/mL. The molar absorptivity and Sandell's sensitivity are 1.0x10(4) L/(mol(.)cm) and 0.0099 mug(.)cm(2) respectively. In addition, the various conditions on determination and the interference of coexisted ions were discussed, and the method was applied to the determination of copper ion both in tea samples and cadmium sulfate reagents. The results are in good agreement with those obtained by ICP AES method.
基金supported by the Natural Science Foundation of China(No.20775060,No.20875077 and No. 20927004)the Natural Science Foundation of Gansu(No.0701RJZA109 and No.0803RJZA105)Key Projects of Scientific Research Base of Department of Education,Gansu Province(No.08zx-07)
文摘The oxidation of hydroquinone(QH_2) was investigated for the first time at liquid/liquid(L/L) interface by scanning electrochemical microscopy(SECM).In this study,electron transfer(ET) from QH_2 in aqueous to ferrocene(Fc) in nitrobenzene (NB) was probed.The apparent heterogeneous rate constants for ET reactions were obtained by fitting the experimental approach curves to the theoretical values.The results showed that the rate constants for oxidation reaction of QH_2 were sensitive to the changes of the dri...
基金supported by the National Natural Science Foundation of China(No.20875077,No.20775060 and No.20927004)the Natural Science Foundation of Gansu(No.0701RJZA109 and No.0803RJZA105)Key Projects of Scientific Research Base of Department of Education,Gansu Province(No.08zx-07).
文摘Comparison in electron transfer(ET) processes from decamethyferrocene(DMFe) in nitrobenzene(NB) to ferric ion in aqueous phase was investigated for the first time by the scanning electrochemical microscopy(SECM).As compared with the system of Fe(CN)_6^(3-)-DMFe,the ET rate obtained from Fe^(3+)-DMFe was lower in spite of larger driving force,which may arise from the effect of reorganization energy.Otherwise,the effect of common ion on rate constants was also probed and results suggested additional complexit...
文摘A new triterpenoid glycoside, named decaisoside F. has been isolated from Decaisnea faresii. Its structure was determined on basis of chi mical method, FAB-MS. homonuclear and heteronuclear correlation esperiments. including H-1--(HCOSY)-H-1. H-1--C-13 COSY, TOSCY, HMBC and NOESY techniques to be 3-O-beta-D- xylopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-Larabinopyranosyl) hederagenin 28-O-beta-D-xylopyranosyl (1-->4)-beta-D-glucopyrancrsyl (1-->6)-beta-D-glucopyranoside.
文摘In this work,by a combination of controlled ring-opening polymerization(CROP) and click reaction,we reported a facile and useful method to synthesize linear poly(ε-caprolactone) at attapulgite nanocomposites with well-defined structures.For this,first, the chlorine terminated attapulgite was prepared by the self-assembly of 3-chloropropyltrimethoxysiIane from the surfaces of attapulgite.And then,the terminal chlorines of modified attapulgite were substituted with azido groups.As the second step,linear propa...
文摘Water-insoluble carboxyl-containing starch graft polymers were prepared. Residual metal ion concentrations in solutions treated with the insoluble starch graft polymers were measured in different pH. The mechanism of removing heavy metals from aqueous solutions with the carboxylated starchs was described.
文摘Three new diterpene alkaloids, transconitine A, B and C were isolated from the roots of Aconitum transsectum Diels, and their structures were elucidated by spectral means.
基金Project supported by the Gansu Province Education Commission and Gansu Province Youth Science.
文摘Hypersensitivity of the ternary complexes Ln(beta-dik)(4)HMQ(where Ln=Nd, Ho, Er, beta-dik=acetylacetonate(AA), dibenzoylmethanate(DBM) and MQ=4-methylquinoline) in acetone solution is studied based on the dynamic coupling model. The structures of these complexes in solution are deduced. Their coordination polyhedrons are all distorted square antiprism. Neodymium complexes have D-2 symmetry, while holmium and erbium complexes have exact D-2d symmetry.
