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2014 Volume 31 Issue 11
2014, 31(11): 1237-1247
doi: 10.3724/SP.J.1095.2014.40006
Abstract:
Gradient copolymers are a relatively new kind of polymer,which exhibit various properties similar to block copolymers.Due to the economical large scale synthesis allowed by one-pot preparation,gradient copolymers attract significant attentions.This review summaries the definition and structure of gradient copolymers,and current research on their synthesis,characterization,self-assembly behaviors as well as properties and applications.
Gradient copolymers are a relatively new kind of polymer,which exhibit various properties similar to block copolymers.Due to the economical large scale synthesis allowed by one-pot preparation,gradient copolymers attract significant attentions.This review summaries the definition and structure of gradient copolymers,and current research on their synthesis,characterization,self-assembly behaviors as well as properties and applications.
2014, 31(11): 1248-1254
doi: 10.3724/SP.J.1095.2014.40055
Abstract:
Polyvinyl chloride(PVC) foam cross-linked by isocyanate and epoxy resin was prepared.Both azobisisobutyronitrile(AIBN) and azodicarbonamide(AC) were used as foaming agents in the prefoam process.Morphologies of foams were characterized by SEM.The effects of particle size,proportion,loading of foaming agents were investigated.The particle size of AIBN has no effect on the cell structure,but the increase of AIBN loading leads to a lower density.The effect of AC particle size on the cell structure is obvious,and the optimal size is 8~20 μm.The cell size mainly depends on the loading of AC.Decomposition of foaming agent was studied by DSC.Both the decomposition behavior of mixed foaming agents and the nucleating effect of AC for the prefoam determine the cell morphology of the resultant foams.The strength increases with the increase of density,but the maximum shear strain appears in the foams with the density of 60~80 kg/m3.
Polyvinyl chloride(PVC) foam cross-linked by isocyanate and epoxy resin was prepared.Both azobisisobutyronitrile(AIBN) and azodicarbonamide(AC) were used as foaming agents in the prefoam process.Morphologies of foams were characterized by SEM.The effects of particle size,proportion,loading of foaming agents were investigated.The particle size of AIBN has no effect on the cell structure,but the increase of AIBN loading leads to a lower density.The effect of AC particle size on the cell structure is obvious,and the optimal size is 8~20 μm.The cell size mainly depends on the loading of AC.Decomposition of foaming agent was studied by DSC.Both the decomposition behavior of mixed foaming agents and the nucleating effect of AC for the prefoam determine the cell morphology of the resultant foams.The strength increases with the increase of density,but the maximum shear strain appears in the foams with the density of 60~80 kg/m3.
2014, 31(11): 1255-1260
doi: 10.3724/SP.J.1095.2014.30661
Abstract:
Novel asymmetric pentamethine cyanine(Cy5) dye with a branched ether chain(polyethylene glycol) was synthesized.The structure of the product was identified by 1H NMR and HRMS.The fluorescence properties and light stability of this Cy5 were investigated.Then albumin bovine serum(BSA) was labeled with this Cy5.The maximum absorption and emission wavelengths of the dye in water were 657 nm and 671 nm.The fluorescence quantum yield(Ф) was 0.24 in water.After irradiated for 8 h,the 4.4% of the aqueous soluble dye was photo-degradated.The dye-to-protein(D/P) value of fluorescent labeling reached 1.57 when the molar ratio of dye and BSA was 2:1.
Novel asymmetric pentamethine cyanine(Cy5) dye with a branched ether chain(polyethylene glycol) was synthesized.The structure of the product was identified by 1H NMR and HRMS.The fluorescence properties and light stability of this Cy5 were investigated.Then albumin bovine serum(BSA) was labeled with this Cy5.The maximum absorption and emission wavelengths of the dye in water were 657 nm and 671 nm.The fluorescence quantum yield(Ф) was 0.24 in water.After irradiated for 8 h,the 4.4% of the aqueous soluble dye was photo-degradated.The dye-to-protein(D/P) value of fluorescent labeling reached 1.57 when the molar ratio of dye and BSA was 2:1.
2014, 31(11): 1261-1267
doi: 10.3724/SP.J.1095.2014.40069
Abstract:
Liquid-crystal molecule with α-cyanostilbene as the core structure,(Z)-2-(4-(dodecylamino) phenyl)-3-(4-(dodecyloxy) phenyl) acrylonitrile(T3),was synthesized.Compound T3 and its analogue(Z)-2-(4-aminophenyl)-3-(4-(dodecyloxy) phenyl)-acrylonitrile(T2) exhibit strong fluorescence both in concentrated solutions and in solid state at blue-green bands.Thermogravimetric analysis for both compounds demonstrates the good thermal stability.Differential scanning calorimetry(DSC) and polarising optical microscope(POM) were used to study the liquid crystal property of compound T3.Molecular arrangement of compound T3 was studied by powder X-ray diffraction.The results indicate the formation of a smectic liquid crystal by compound T3.
Liquid-crystal molecule with α-cyanostilbene as the core structure,(Z)-2-(4-(dodecylamino) phenyl)-3-(4-(dodecyloxy) phenyl) acrylonitrile(T3),was synthesized.Compound T3 and its analogue(Z)-2-(4-aminophenyl)-3-(4-(dodecyloxy) phenyl)-acrylonitrile(T2) exhibit strong fluorescence both in concentrated solutions and in solid state at blue-green bands.Thermogravimetric analysis for both compounds demonstrates the good thermal stability.Differential scanning calorimetry(DSC) and polarising optical microscope(POM) were used to study the liquid crystal property of compound T3.Molecular arrangement of compound T3 was studied by powder X-ray diffraction.The results indicate the formation of a smectic liquid crystal by compound T3.
2014, 31(11): 1268-1272
doi: 10.3724/SP.J.1095.2014.30642
Abstract:
This paper reported the bromination of 2-methyl-1,8-naphthyridine derivatives.Monobrominated products,2-bromomethyl-1,8-naphthyridine derivatives,and dibrominated byproducts were obtained with N-bromosuccimide(NBS) as the bromination agent under infrared light.Two synthetic conditions were evaluated.The yield of monobrominated products is up to 54.6% under the optimized condition of 2-methyl-1,8-naphthyrdine derivatives and NBS in molar ratio of 1:1.2 under 500 W infrared light.
This paper reported the bromination of 2-methyl-1,8-naphthyridine derivatives.Monobrominated products,2-bromomethyl-1,8-naphthyridine derivatives,and dibrominated byproducts were obtained with N-bromosuccimide(NBS) as the bromination agent under infrared light.Two synthetic conditions were evaluated.The yield of monobrominated products is up to 54.6% under the optimized condition of 2-methyl-1,8-naphthyrdine derivatives and NBS in molar ratio of 1:1.2 under 500 W infrared light.
2014, 31(11): 1273-1279
doi: 10.3724/SP.J.1095.2014.40001
Abstract:
Starting from 4-amino nitrobenzene,3',5'-dibromo-3-methoxy-4-hydroxyazobenzene(6) was synthesized via sequential reactions of dibromination,diazotization deamination,nitro-reduction and diazo coupling.Polymethyl methacrylate(PMMA) films containing azobenzene 6 were obtained by a physical doping process.The structure of the title compound was characterized by elemental analysis,FT-IR,MS(ESI),1H NMR,13C NMR,MS,especially by the X-ray single crystal diffraction.The crystal crystallizes in the monoclinic space group C2/c,with a=1.6182(3) nm,b=0.81847(16) nm,c=2.1945(4) nm,β=102.819(2)°,V=2.8342(10) nm3,Z=8,Dc=1.809 g/cm3,μ=5.719 mm-1,F(000)=1504,R1=0.0366 and ωR2=0.0764.The title compound exists in the trans-form.The intermolecular hydrogen bonds and π-π stacking between benzene rings contributes to one-dimensional infinite chain structure along b axis.By UV-Vis spectroscopy method,the reaction rate constants for trans-cis photoisomerization and cis-trans thermal back-isomerization are at the range of 10-1~10-2min-1.
Starting from 4-amino nitrobenzene,3',5'-dibromo-3-methoxy-4-hydroxyazobenzene(6) was synthesized via sequential reactions of dibromination,diazotization deamination,nitro-reduction and diazo coupling.Polymethyl methacrylate(PMMA) films containing azobenzene 6 were obtained by a physical doping process.The structure of the title compound was characterized by elemental analysis,FT-IR,MS(ESI),1H NMR,13C NMR,MS,especially by the X-ray single crystal diffraction.The crystal crystallizes in the monoclinic space group C2/c,with a=1.6182(3) nm,b=0.81847(16) nm,c=2.1945(4) nm,β=102.819(2)°,V=2.8342(10) nm3,Z=8,Dc=1.809 g/cm3,μ=5.719 mm-1,F(000)=1504,R1=0.0366 and ωR2=0.0764.The title compound exists in the trans-form.The intermolecular hydrogen bonds and π-π stacking between benzene rings contributes to one-dimensional infinite chain structure along b axis.By UV-Vis spectroscopy method,the reaction rate constants for trans-cis photoisomerization and cis-trans thermal back-isomerization are at the range of 10-1~10-2min-1.
2014, 31(11): 1280-1289
doi: 10.3724/SP.J.1095.2014.40064
Abstract:
The C-H arylation of various phosphinic acid derivatives was investigated.After a comprehensive screen of various reaction parameters,we found that direct C——H arylation of aryl phosphinamides could proceed effectively with Pd(OAc)2 as catalyst,Ag2CO3 as oxidant,and benzoquinone(BQ) as additive in DMF.Mechanistic study revealed that the reaction proceeded via a Pd(Ⅱ) to Pd(0) cycle.Further elaboration demonstrated that arylated phosphinamides could be converted into the corresponding aryl phosphinates and H-biaryl phosphines in high efficiency,with yields of 98% and 82%,respectively.Consequently,the results presented herein would offer a new method for the synthesis of polyaryl phosphorus compounds.
The C-H arylation of various phosphinic acid derivatives was investigated.After a comprehensive screen of various reaction parameters,we found that direct C——H arylation of aryl phosphinamides could proceed effectively with Pd(OAc)2 as catalyst,Ag2CO3 as oxidant,and benzoquinone(BQ) as additive in DMF.Mechanistic study revealed that the reaction proceeded via a Pd(Ⅱ) to Pd(0) cycle.Further elaboration demonstrated that arylated phosphinamides could be converted into the corresponding aryl phosphinates and H-biaryl phosphines in high efficiency,with yields of 98% and 82%,respectively.Consequently,the results presented herein would offer a new method for the synthesis of polyaryl phosphorus compounds.
2014, 31(11): 1290-1296
doi: 10.3724/SP.J.1095.2014.40035
Abstract:
Using 2,4-dichlorobenzoic acid and 2-amino-3-methylbenzoic acid as starting materials,eight novel anthranilic diamide derivatives containing 1,2,4-triazole Schiff base and 2,4-dichlorophenyl unit were synthesized.The structures were confirmed by 1H NMR,IR and elemental analysis.The preliminary bioassay showed that compound 9a has significant insecticidal activity with 100% inhibition of Leucania separata and Plutella xylostella at 600 mg/L.
Using 2,4-dichlorobenzoic acid and 2-amino-3-methylbenzoic acid as starting materials,eight novel anthranilic diamide derivatives containing 1,2,4-triazole Schiff base and 2,4-dichlorophenyl unit were synthesized.The structures were confirmed by 1H NMR,IR and elemental analysis.The preliminary bioassay showed that compound 9a has significant insecticidal activity with 100% inhibition of Leucania separata and Plutella xylostella at 600 mg/L.
2014, 31(11): 1297-1301
doi: 10.3724/SP.J.1095.2014.40024
Abstract:
The synthesis of irone was investigated by cyclization reaction from raw material 9,10-cyclomethylene pseudoionones.The cyclization mechanism was preliminarily studied.The optimal cyclization conditions for irone are to keep the reaction time within 45 min,the reaction temperature at-70℃,and the molar ratio of 9,10-cyclomethylene pseudoionones to chlorosulfonic acid at 1:4.The combined yield of irone isomers can reach 90.1%,and the content of α-irone,β-irone and γ-irone are 60.2%,29.0% and 8.0%,respectively,under the optimal cyclization conditions(determined by GC with area normalization method).The structures of irone isomers were also confirmed by 1H NMR and 13C NMR.Preliminary mechanism study indicates that the cyclization reaction for the synthesis of irone can finish rapidly at low temperature.
The synthesis of irone was investigated by cyclization reaction from raw material 9,10-cyclomethylene pseudoionones.The cyclization mechanism was preliminarily studied.The optimal cyclization conditions for irone are to keep the reaction time within 45 min,the reaction temperature at-70℃,and the molar ratio of 9,10-cyclomethylene pseudoionones to chlorosulfonic acid at 1:4.The combined yield of irone isomers can reach 90.1%,and the content of α-irone,β-irone and γ-irone are 60.2%,29.0% and 8.0%,respectively,under the optimal cyclization conditions(determined by GC with area normalization method).The structures of irone isomers were also confirmed by 1H NMR and 13C NMR.Preliminary mechanism study indicates that the cyclization reaction for the synthesis of irone can finish rapidly at low temperature.
2014, 31(11): 1302-1309
doi: 10.3724/SP.J.1095.2014.40029
Abstract:
Ti-Mn-β zeolite was hydrothermally synthesized in a SiO2-SiO2-MnO2-(TEA)2O-H2O-NH4F system.The structural characteristics of the products were determined by X-ray diffraction,infrared spectroscopy,UV-Vis diffuse reflectance spectroscopy,thermogravimetry-differential thermal analysis,scanning electron microscopy,and X-ray photoelectron spectroscopy.The factors affecting the synthesis of TiMn-β zeolite were investigated.The results show that the Ti-Mn-β zeolites have good catalytic activity in the hydroxylation of phenol with H2O2 as the oxidant.The phenol conversion is 29.8%,and the selectivities for catechnol and hydroquinone are 70.9% and 26%,respectively.
Ti-Mn-β zeolite was hydrothermally synthesized in a SiO2-SiO2-MnO2-(TEA)2O-H2O-NH4F system.The structural characteristics of the products were determined by X-ray diffraction,infrared spectroscopy,UV-Vis diffuse reflectance spectroscopy,thermogravimetry-differential thermal analysis,scanning electron microscopy,and X-ray photoelectron spectroscopy.The factors affecting the synthesis of TiMn-β zeolite were investigated.The results show that the Ti-Mn-β zeolites have good catalytic activity in the hydroxylation of phenol with H2O2 as the oxidant.The phenol conversion is 29.8%,and the selectivities for catechnol and hydroquinone are 70.9% and 26%,respectively.
2014, 31(11): 1310-1316
doi: 10.3724/SP.J.1095.2014.30653
Abstract:
A Keggin-type biimidazole tungstogermanate(H4biim)[H2GeW12O40]·18H2O(1b,H2biim=2,2'-biimidazole),as a catalyst for the synthesis of cyclohexanone ethylene ketal,was designed and synthesized.It was characterized by single crystal X-ray diffraction analysis,infrared spectroscopy(FT-IR),ultraviolet spectroscopy(UV),themogravimetry-differential thermal analysis(TG-DTA) and X-ray powder diffraction(XRD).Factors,such as the molar ratio of cyclohexanone to ethylene glycol,catalyst loading and reaction time,on the yield were investigated.The experimental results show that the product yield reaches 90% under the optimal conditions:n(cyclohexanone):n(1,2-ethanediol)=1:1.4,n(1b,based on W):n(cyclohexanone)=1:260,reaction time is 2 h.The catalyst can be reused and has good stability in the catalytic reaction.
A Keggin-type biimidazole tungstogermanate(H4biim)[H2GeW12O40]·18H2O(1b,H2biim=2,2'-biimidazole),as a catalyst for the synthesis of cyclohexanone ethylene ketal,was designed and synthesized.It was characterized by single crystal X-ray diffraction analysis,infrared spectroscopy(FT-IR),ultraviolet spectroscopy(UV),themogravimetry-differential thermal analysis(TG-DTA) and X-ray powder diffraction(XRD).Factors,such as the molar ratio of cyclohexanone to ethylene glycol,catalyst loading and reaction time,on the yield were investigated.The experimental results show that the product yield reaches 90% under the optimal conditions:n(cyclohexanone):n(1,2-ethanediol)=1:1.4,n(1b,based on W):n(cyclohexanone)=1:260,reaction time is 2 h.The catalyst can be reused and has good stability in the catalytic reaction.
2014, 31(11): 1317-1322
doi: 10.3724/SP.J.1095.2014.40022
Abstract:
The nano-scale pure ZrO2 and the Y2O3-doped ZrO2(ZrO2-Y) were prepared by the hydrothermal synthesis method,and investigated as supports of Ru-La-B/ZrO2 catalysts.It was confirmed that both of them have similar crystallite size,texture property and particle size distribution.ZrO2 only has a monoclinic phase.ZrO2-Y not only has a monoclinic phase,but also some of the tetragonal phase.Y2O3 doping can affect the composition and the phase structure of ZrO2.The Y2O3 doping can cover some of the active sites which are unsuitable for the formation of cyclohexene.Thus the activity of the catalyst supported on ZrO2-Y is lower than that of catalyst supported on ZrO2,and the selectivity to cyclohexene of the former is higher than that of the latter at low benzene conversion.The Ru-La-B catalysts supported on ZrO2-Y has a poorer hydrophilicity than that supported on ZrO2 due to the lower content of the surface hydroxyl groups on the tetragonal phase of ZrO2-Y.It is difficult for cyclohexne to be desorbed from the surface of the catalyst with ZrO2-Y as supports.Thus the selectivity to cyclohexene of the catalyst supported on ZrO2-Y is lower than that supported on ZrO2 when the benzene conversion exceeds 52.0%.A cyclohexene yield of 52.1% is achieved on the Ru-La-B catalysts supported on ZrO2 at 20 min,however,only 45.2% is obtained on that supported on ZrO2-Y.Therefore,the nano-scale monoclinic ZrO2 is more suitable support of the catalyst for the selective hydrogenation of benzene to cyclohexene.
The nano-scale pure ZrO2 and the Y2O3-doped ZrO2(ZrO2-Y) were prepared by the hydrothermal synthesis method,and investigated as supports of Ru-La-B/ZrO2 catalysts.It was confirmed that both of them have similar crystallite size,texture property and particle size distribution.ZrO2 only has a monoclinic phase.ZrO2-Y not only has a monoclinic phase,but also some of the tetragonal phase.Y2O3 doping can affect the composition and the phase structure of ZrO2.The Y2O3 doping can cover some of the active sites which are unsuitable for the formation of cyclohexene.Thus the activity of the catalyst supported on ZrO2-Y is lower than that of catalyst supported on ZrO2,and the selectivity to cyclohexene of the former is higher than that of the latter at low benzene conversion.The Ru-La-B catalysts supported on ZrO2-Y has a poorer hydrophilicity than that supported on ZrO2 due to the lower content of the surface hydroxyl groups on the tetragonal phase of ZrO2-Y.It is difficult for cyclohexne to be desorbed from the surface of the catalyst with ZrO2-Y as supports.Thus the selectivity to cyclohexene of the catalyst supported on ZrO2-Y is lower than that supported on ZrO2 when the benzene conversion exceeds 52.0%.A cyclohexene yield of 52.1% is achieved on the Ru-La-B catalysts supported on ZrO2 at 20 min,however,only 45.2% is obtained on that supported on ZrO2-Y.Therefore,the nano-scale monoclinic ZrO2 is more suitable support of the catalyst for the selective hydrogenation of benzene to cyclohexene.
2014, 31(11): 1323-1329
doi: 10.3724/SP.J.1095.2014.40030
Abstract:
A series of La2O3/ZrO2 solid base catalysts has been prepared via templated pathway.The solid base catalysts were characterized by BET,XRD,XPS,and SEM.Compared with samples prepared by impregnation and co-precipitation method,the as-prepared mixed oxides catalysts replicated the biomorphic of birch and possessed high specific surface area,low grain size and high pore volume.The transesterification of jatropha oil with methanol was studied by using these mixed oxides catalysts.Alkaline and catalytic performance are optimal when the mass ratio of La2O3 is 10%.Under the condition of alcohol/oil molar ratio 72:1,catalyst/oil mass ratio 8%,reaction temperature 373 K and reaction time 6 h,jatropha oil conversion reaches 93.6%.This optimal catalyst exhibits significant degree of acid and water resistance.At the same reaction conditions,biodiesel production can still remain about 83% after three times recycle of the catalysis.
A series of La2O3/ZrO2 solid base catalysts has been prepared via templated pathway.The solid base catalysts were characterized by BET,XRD,XPS,and SEM.Compared with samples prepared by impregnation and co-precipitation method,the as-prepared mixed oxides catalysts replicated the biomorphic of birch and possessed high specific surface area,low grain size and high pore volume.The transesterification of jatropha oil with methanol was studied by using these mixed oxides catalysts.Alkaline and catalytic performance are optimal when the mass ratio of La2O3 is 10%.Under the condition of alcohol/oil molar ratio 72:1,catalyst/oil mass ratio 8%,reaction temperature 373 K and reaction time 6 h,jatropha oil conversion reaches 93.6%.This optimal catalyst exhibits significant degree of acid and water resistance.At the same reaction conditions,biodiesel production can still remain about 83% after three times recycle of the catalysis.
2014, 31(11): 1330-1335
doi: 10.3724/SP.J.1095.2014.40040
Abstract:
Pt is the best electrocatalyst for the oxygen reduction reactions(ORR).However,there are several major drawbacks,such as high cost and intolerance to the presence of intermediate species.In this paper,we use ethylene diamine tetramethylene phosphonic acid(EDTMP) as complexing-reducing agent to synthesize Ag nanoparticles.The silver nanoparticles obtained after 6 h of reduction reaction and characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM),show uniform dispersion with the particle size about 6 nm.The electrochemical tests indicated that the Ag nanoparticles exhibit superior ORR activity under alkaline conditions than that of Ag nanoparticles prepared by the conventional NaBH4 reduction.The half-wave potential(E1/2) of ORR for previous catalysis has a positive shift of 60 mV.
Pt is the best electrocatalyst for the oxygen reduction reactions(ORR).However,there are several major drawbacks,such as high cost and intolerance to the presence of intermediate species.In this paper,we use ethylene diamine tetramethylene phosphonic acid(EDTMP) as complexing-reducing agent to synthesize Ag nanoparticles.The silver nanoparticles obtained after 6 h of reduction reaction and characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM),show uniform dispersion with the particle size about 6 nm.The electrochemical tests indicated that the Ag nanoparticles exhibit superior ORR activity under alkaline conditions than that of Ag nanoparticles prepared by the conventional NaBH4 reduction.The half-wave potential(E1/2) of ORR for previous catalysis has a positive shift of 60 mV.
2014, 31(11): 1336-1344
doi: 10.3724/SP.J.1095.2014.40045
Abstract:
A copper-iron dual metal hexacyanoferrates(CuFeHCF),multi-walled carbon nanotube(MWCNT) modified composite ceramic carbon electrode(CCE)(CuFeHCF/MWCNT/CCE) was fabricated by using cyclic voltammetry.The electrochemical behavior and the electroctalytic activity of this modified electrode were also investigated carefully.The results show that the resulting modified electrode exhibits strongly electrocatalytic activity for the oxidation of nitrite.Based on this electrocatalytic property,an amperometry for the determination of nitrite was established.Under the optimum condition,the liner relationship between the catalytic current and the nitrite concentration is in the range of 2.0×10-7~1.4×10-3 mol/L.The sensitivity and the detection limit are 104.1 μA/(mmol·L-1) and 5.0×10-8 mol/L,respectively.The proposed method was applied to detect nitrite in real samples with satisfactory results.
A copper-iron dual metal hexacyanoferrates(CuFeHCF),multi-walled carbon nanotube(MWCNT) modified composite ceramic carbon electrode(CCE)(CuFeHCF/MWCNT/CCE) was fabricated by using cyclic voltammetry.The electrochemical behavior and the electroctalytic activity of this modified electrode were also investigated carefully.The results show that the resulting modified electrode exhibits strongly electrocatalytic activity for the oxidation of nitrite.Based on this electrocatalytic property,an amperometry for the determination of nitrite was established.Under the optimum condition,the liner relationship between the catalytic current and the nitrite concentration is in the range of 2.0×10-7~1.4×10-3 mol/L.The sensitivity and the detection limit are 104.1 μA/(mmol·L-1) and 5.0×10-8 mol/L,respectively.The proposed method was applied to detect nitrite in real samples with satisfactory results.
Molecular Dynamics Simulation of Tip Functionalized Carbon Nanotube Membrane for Li+/Mg2+ Separation
2014, 31(11): 1345-1351
doi: 10.3724/SP.J.1095.2014.30622
Abstract:
Using molecular dynamics simulations,we studied the transport of Li+ and Mg2+ through membrane formed from armchair type(10,10) carbon nanotubes whose top rims were modified with a range of different charged functional groups including COO- and NH3+ under 80 MPa hydrostatic pressure,and investigated the potential of mean force,conductance and density distributions of ions in the carbon nanotubes.The results show that appropriately modified(10,10) carbon nanotubes can effectively extract Li+.The bound and rejection effects produced by electrostatic interaction between charged groups and ions reduce the conductance of ions in the tubes.Mg2+ can permeate the functionalized carbon nanotubes and Li+ are also completely blocked with the addition of 8COO- and 4NH3+.The maximum conductance of Li+ are found in carbon nanotubes modified with 1COO- and 1NH3+ functional groups which can most effectively separate Li+ and Mg2+.Therefore,through addition of specific charged modified groups,the separation performance of large diameter carbon nanotube to Li+ and Mg2+ can be effectively improved.Charge properties and the quantity of modification groups greatly affect the separation effects.
Using molecular dynamics simulations,we studied the transport of Li+ and Mg2+ through membrane formed from armchair type(10,10) carbon nanotubes whose top rims were modified with a range of different charged functional groups including COO- and NH3+ under 80 MPa hydrostatic pressure,and investigated the potential of mean force,conductance and density distributions of ions in the carbon nanotubes.The results show that appropriately modified(10,10) carbon nanotubes can effectively extract Li+.The bound and rejection effects produced by electrostatic interaction between charged groups and ions reduce the conductance of ions in the tubes.Mg2+ can permeate the functionalized carbon nanotubes and Li+ are also completely blocked with the addition of 8COO- and 4NH3+.The maximum conductance of Li+ are found in carbon nanotubes modified with 1COO- and 1NH3+ functional groups which can most effectively separate Li+ and Mg2+.Therefore,through addition of specific charged modified groups,the separation performance of large diameter carbon nanotube to Li+ and Mg2+ can be effectively improved.Charge properties and the quantity of modification groups greatly affect the separation effects.
2014, 31(11): 1352-1355
doi: 10.3724/SP.J.1095.2014.40003
Abstract:
A method for the determination of banned additive,methenamine,in dried beancurd stick and bean vermicelli by ion chromatography was established.The extraction conditions and extraction solvents were optimized.Results showed a good linearity in the range of 0.10~4.0 μg/g for methenamine with the related coefficient of 0.99937.The detection limit of the proposed method for dried beancurd stick and bean vermicelli was 0.079 μg/g.Spiked recoveries were in the range of 86%~96% and the relative standard deviation was 1.9%.The proposed method is simple and rapid and can be applied to the analysis of methenamine in dried beancurd stick and bean vermicelli.
A method for the determination of banned additive,methenamine,in dried beancurd stick and bean vermicelli by ion chromatography was established.The extraction conditions and extraction solvents were optimized.Results showed a good linearity in the range of 0.10~4.0 μg/g for methenamine with the related coefficient of 0.99937.The detection limit of the proposed method for dried beancurd stick and bean vermicelli was 0.079 μg/g.Spiked recoveries were in the range of 86%~96% and the relative standard deviation was 1.9%.The proposed method is simple and rapid and can be applied to the analysis of methenamine in dried beancurd stick and bean vermicelli.
2014, 31(11): 1356-1358
doi: 10.3724/SP.J.1095.2014.40054
Abstract:
Rhodium-catalyzed asymmetric hydrogenation of 2-phenylprop-2-en-1-ol was investigated for the first time.Enantioselective synthesis of chiral 2-phenylpropanol with up to 70% ee was achieved through screen on a series of monodentate ligands and bidentate ligands.
Rhodium-catalyzed asymmetric hydrogenation of 2-phenylprop-2-en-1-ol was investigated for the first time.Enantioselective synthesis of chiral 2-phenylpropanol with up to 70% ee was achieved through screen on a series of monodentate ligands and bidentate ligands.
