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2006 Volume 23 Issue 7
2006, 23(7): 697-703
Abstract:
Polybenzimidazole(PBI) composite membranes were prepared.The introduced components included inorganic proton conductor,Zr(HPO4)2·nH2O(ZrP) together with polysulfone(PSF) and the acid form of sulfonated polysulfone(SPSF(H)).Thermogravimetric analysis indicated that the composite membranes were thermal stable up to 400℃ for the PBI/ZrP/PSF system and 230℃ for the PBI/SPSF(H) system,respectively.Phosphoric acid doped PBI composite membranes exhibited a high conductivity at temperatures up to 200℃ under low humidity.(Single) cell tests with electrolytes of acid doped PBI composites were performed at 200℃ under atmospheric pressure and without humidification.The maximum power density of the cell with hydrogen or oxygen as the fuel gas is 0.34 W/cm2 for PBI/ZrP/PSF(mass ratio 80:15:5),and 0.38 W/cm2 for acid doped PBI/SPSF(0.43H),respectively.
Polybenzimidazole(PBI) composite membranes were prepared.The introduced components included inorganic proton conductor,Zr(HPO4)2·nH2O(ZrP) together with polysulfone(PSF) and the acid form of sulfonated polysulfone(SPSF(H)).Thermogravimetric analysis indicated that the composite membranes were thermal stable up to 400℃ for the PBI/ZrP/PSF system and 230℃ for the PBI/SPSF(H) system,respectively.Phosphoric acid doped PBI composite membranes exhibited a high conductivity at temperatures up to 200℃ under low humidity.(Single) cell tests with electrolytes of acid doped PBI composites were performed at 200℃ under atmospheric pressure and without humidification.The maximum power density of the cell with hydrogen or oxygen as the fuel gas is 0.34 W/cm2 for PBI/ZrP/PSF(mass ratio 80:15:5),and 0.38 W/cm2 for acid doped PBI/SPSF(0.43H),respectively.
2006, 23(7): 704-707
Abstract:
Teardrop-shaped and tetrapod-shaped CdS nanocrystals were prepared in aqueous solution under mild conditions through adjusting the concentration of reactants and the equilibrium reaction.Effects of the precursors on nanorods were further discussed.TEM images showed that nanocrystals had a narrow size distribution and a controllable aspect ratio(1~7) to some extent,and XRD measurement confirmed the wurtzite structure for the resulting CdS nanorods.
Teardrop-shaped and tetrapod-shaped CdS nanocrystals were prepared in aqueous solution under mild conditions through adjusting the concentration of reactants and the equilibrium reaction.Effects of the precursors on nanorods were further discussed.TEM images showed that nanocrystals had a narrow size distribution and a controllable aspect ratio(1~7) to some extent,and XRD measurement confirmed the wurtzite structure for the resulting CdS nanorods.
2006, 23(7): 708-712
Abstract:
The resonance Rayleigh scattering(RRS),second-order scattering(SOS) and frequency-double scattering(FDS) methods were used to study the interaction of NaCMC with nile blue sulphate in a pH 6.0 Britton-Robinson buffer solution.The results showed that the reaction could result in strong enhancement of RRS,SOS and FDS.The maximum peaks were located at 298 nm(RRS),500 nm(SOS) and 392 nm(FDS). Three scattering intensities were proportional to the concentration of NaCMC in the range of 5.0×10-8~3.0×10-6 g /mL(RRS),5.0×10-8~2.5×10-6 g/mL(SOS and FDS).The detect limit was 1.8×10-9 g/mL for RRS and SOS and 3.8×10-9 g/mL for FDS.The three methods were applied to the determination of the concentration of NaCMC in synthetic samples and tobacco extracts with satisfactory results.
The resonance Rayleigh scattering(RRS),second-order scattering(SOS) and frequency-double scattering(FDS) methods were used to study the interaction of NaCMC with nile blue sulphate in a pH 6.0 Britton-Robinson buffer solution.The results showed that the reaction could result in strong enhancement of RRS,SOS and FDS.The maximum peaks were located at 298 nm(RRS),500 nm(SOS) and 392 nm(FDS). Three scattering intensities were proportional to the concentration of NaCMC in the range of 5.0×10-8~3.0×10-6 g /mL(RRS),5.0×10-8~2.5×10-6 g/mL(SOS and FDS).The detect limit was 1.8×10-9 g/mL for RRS and SOS and 3.8×10-9 g/mL for FDS.The three methods were applied to the determination of the concentration of NaCMC in synthetic samples and tobacco extracts with satisfactory results.
2006, 23(7): 713-717
Abstract:
Carbon nanotubes supported NiB and Ni-M(x%)-B(M=Ag,Cu) amorphous alloy catalysts were prepared by the impregnation-chemical reductant method with the aid of ultrasonication.The experiments of acetylene) half-hydrogenation showed that an addition of 1% Ag to NiB/CNTs decreased considerably the hydrogenation) activity but enhanced the selectivity of ethylene.when doping Cu ranging from 3% to 5%,Ni-Cu-B/CNTs catalysts exhibited better catalytic activity and slightly higher ethylene selectivity.
Carbon nanotubes supported NiB and Ni-M(x%)-B(M=Ag,Cu) amorphous alloy catalysts were prepared by the impregnation-chemical reductant method with the aid of ultrasonication.The experiments of acetylene) half-hydrogenation showed that an addition of 1% Ag to NiB/CNTs decreased considerably the hydrogenation) activity but enhanced the selectivity of ethylene.when doping Cu ranging from 3% to 5%,Ni-Cu-B/CNTs catalysts exhibited better catalytic activity and slightly higher ethylene selectivity.
2006, 23(7): 718-723
Abstract:
A series of L-histidine Schiff bases that include Sal-His (H2L1),Br-Sal-His (H2L2),NO2-Sal-His (H2L3) and their Cu(Ⅱ) complexes were synthesized,and the catalytic behavior of Schiff-base-Cu for the oxidation of β-ionone to 4-oxo-β-ionone as well as the effects of substitutents on these properties were examined.The effects of reaction temperature,reaction time,molar ratio of catalyst to β-ionone, the amount of pyridine additive and O2 pressure on the catalytic activity of the various catalysts were optimized and a probable catalytic mechanism was proposed.The results showed that the catalytic performances of Schiff-base-Cu(Ⅱ) complexes were affected by substituted groups and enhanced by additive pyridine.The main product was 4-oxo-β-(ionone) with a yield of 50.2% and a purity over 98.5% under O2 pressure(1 MPa) at 75℃ with additive pyridine over catalyst CuL2 in 10 h.The structures of L-histidine Schiff bases,their Cu(Ⅱ) complexes and oxidation product were characterized by IR,MS,1H NMR and EA.The excessive β-ionone and the catalysts can be reused via vacuum distillation and filtration.
A series of L-histidine Schiff bases that include Sal-His (H2L1),Br-Sal-His (H2L2),NO2-Sal-His (H2L3) and their Cu(Ⅱ) complexes were synthesized,and the catalytic behavior of Schiff-base-Cu for the oxidation of β-ionone to 4-oxo-β-ionone as well as the effects of substitutents on these properties were examined.The effects of reaction temperature,reaction time,molar ratio of catalyst to β-ionone, the amount of pyridine additive and O2 pressure on the catalytic activity of the various catalysts were optimized and a probable catalytic mechanism was proposed.The results showed that the catalytic performances of Schiff-base-Cu(Ⅱ) complexes were affected by substituted groups and enhanced by additive pyridine.The main product was 4-oxo-β-(ionone) with a yield of 50.2% and a purity over 98.5% under O2 pressure(1 MPa) at 75℃ with additive pyridine over catalyst CuL2 in 10 h.The structures of L-histidine Schiff bases,their Cu(Ⅱ) complexes and oxidation product were characterized by IR,MS,1H NMR and EA.The excessive β-ionone and the catalysts can be reused via vacuum distillation and filtration.
2006, 23(7): 724-728
Abstract:
A grafted copolymer(CPE-g-MMA),composed of poly(methyl methacrylate)(PMMA) as branched chains and chlorinated polyethylene(CPE) as backbone was synthesized by in-situ chlorinating graft copolymerization based on HDPE.It was characterized by FT-IR,GPC and DSC.The graft parameters and mechanical property of the polymer were measured.The graft chains are short and there are much more graft chains on the backbone chains.The results show that the graft copolymer obtained by in-situ chlorinating has good properties.
A grafted copolymer(CPE-g-MMA),composed of poly(methyl methacrylate)(PMMA) as branched chains and chlorinated polyethylene(CPE) as backbone was synthesized by in-situ chlorinating graft copolymerization based on HDPE.It was characterized by FT-IR,GPC and DSC.The graft parameters and mechanical property of the polymer were measured.The graft chains are short and there are much more graft chains on the backbone chains.The results show that the graft copolymer obtained by in-situ chlorinating has good properties.
2006, 23(7): 729-733
Abstract:
Complex of chitosan and Cu(Ⅱ)(CTS-Cu) was prepared through homogenous liquid coordination.IR,DTA,and XRD analysis were utilized to determine the structure of the complex.IR peaks of N-H,C-N,and C-O-C are red shifted.The exothermal peak of chitosan chain fragmentation decreased from 358℃ of chitosan to 285℃ of CTS-Cu.XRD peaks of chitosan located at 9.83°,10.58°,19.78°,22.45°,and 27.71° were absence in CTS-Cu's diffraction pattern.These results showed that there were coordinating bonds between chitosan and Cu(Ⅱ),and CTS-Cu contained more amorphous domains which allowed a better accessibility to reactants and thus a better reactivity.On the other hand there are some coordinating bonds within CTS-Cu that are easy to be broken.H2O2 was used to degrade CTS-Cu and chitosan. Under the same conditions,the degradative velocity of CTS-Cu was faster than that of chitosan,and the degraded molecular distribution of the former case was much narrower than that of the latter.After chitosan degrading for 2 h,the viscocity of CTS-Cu decreased 82.9%,while chitosan just decreased 16.6% in terms of viscosity. Dynamics of CTS-Cu degradation showed CTS-Cu could catalyze H2O2 decomposition.After elimination,the content of copper in low molecular weight chitosan could be less than 1.0 μmol/L.
Complex of chitosan and Cu(Ⅱ)(CTS-Cu) was prepared through homogenous liquid coordination.IR,DTA,and XRD analysis were utilized to determine the structure of the complex.IR peaks of N-H,C-N,and C-O-C are red shifted.The exothermal peak of chitosan chain fragmentation decreased from 358℃ of chitosan to 285℃ of CTS-Cu.XRD peaks of chitosan located at 9.83°,10.58°,19.78°,22.45°,and 27.71° were absence in CTS-Cu's diffraction pattern.These results showed that there were coordinating bonds between chitosan and Cu(Ⅱ),and CTS-Cu contained more amorphous domains which allowed a better accessibility to reactants and thus a better reactivity.On the other hand there are some coordinating bonds within CTS-Cu that are easy to be broken.H2O2 was used to degrade CTS-Cu and chitosan. Under the same conditions,the degradative velocity of CTS-Cu was faster than that of chitosan,and the degraded molecular distribution of the former case was much narrower than that of the latter.After chitosan degrading for 2 h,the viscocity of CTS-Cu decreased 82.9%,while chitosan just decreased 16.6% in terms of viscosity. Dynamics of CTS-Cu degradation showed CTS-Cu could catalyze H2O2 decomposition.After elimination,the content of copper in low molecular weight chitosan could be less than 1.0 μmol/L.
2006, 23(7): 734-738
Abstract:
The pure and La-doped TiO2/AC catalysts were prepared on the surface of active carbon(AC) via the sol-gel method with tetrabutylorthotitanat and lanthanum nitrate as source materials.The crystalline structures and morphologies were characterized by means of XRD,UV-Vis and SEM.The effects of calcining temperature and La content on the properties and the photocatalytic activity of TiO2/AC catalysts for the degradation of methylene blue have been carefully investigated.The results show that La dopant not only greatly inhibits TiO2 crystal phase transformation from anatase to rutile,but also makes the optic response range of TiO2 particle expand to visible light.It was found that the degradation rate of methylene blue reached 87% when the molar fraction of La in TiO2 was 0.30% and the irradiation time was 120 min.
The pure and La-doped TiO2/AC catalysts were prepared on the surface of active carbon(AC) via the sol-gel method with tetrabutylorthotitanat and lanthanum nitrate as source materials.The crystalline structures and morphologies were characterized by means of XRD,UV-Vis and SEM.The effects of calcining temperature and La content on the properties and the photocatalytic activity of TiO2/AC catalysts for the degradation of methylene blue have been carefully investigated.The results show that La dopant not only greatly inhibits TiO2 crystal phase transformation from anatase to rutile,but also makes the optic response range of TiO2 particle expand to visible light.It was found that the degradation rate of methylene blue reached 87% when the molar fraction of La in TiO2 was 0.30% and the irradiation time was 120 min.
2006, 23(7): 739-742
Abstract:
The formation of lead oxide,mono-oxide and dioxide,on Pb-Bi alloys in sulfuric solution was studied by means of linear sweeping voltammetry(LSV),scan electron spectroscopy(SEM),AC voltammetry and inductively coupled plasma atomic emission spectrum(ICP).The results obtained by LSV after applying a potential at 0.9 V for 20 min show that bismuth content lower than 0.103% in the alloys does not affect the formation of mono-oxide,but it will accelerate the formation of the mono-oxide when its content in the alloys is higher.Z' versus E curves indicate that the conductance increases with bismuth content increasing;similar behavior for the effect of bismuth on the formation of dioxide as that of mono-oxide can be found from the results obtained by LSV after applying a potential at 1.6 V for 20 min.It is shown by SEM that the oxides have more pores on the alloys with high bismuth content.It is found from ICP analysis that the stripping amount of bismuth in the alloys increases with bismuth content increasing.
The formation of lead oxide,mono-oxide and dioxide,on Pb-Bi alloys in sulfuric solution was studied by means of linear sweeping voltammetry(LSV),scan electron spectroscopy(SEM),AC voltammetry and inductively coupled plasma atomic emission spectrum(ICP).The results obtained by LSV after applying a potential at 0.9 V for 20 min show that bismuth content lower than 0.103% in the alloys does not affect the formation of mono-oxide,but it will accelerate the formation of the mono-oxide when its content in the alloys is higher.Z' versus E curves indicate that the conductance increases with bismuth content increasing;similar behavior for the effect of bismuth on the formation of dioxide as that of mono-oxide can be found from the results obtained by LSV after applying a potential at 1.6 V for 20 min.It is shown by SEM that the oxides have more pores on the alloys with high bismuth content.It is found from ICP analysis that the stripping amount of bismuth in the alloys increases with bismuth content increasing.
2006, 23(7): 743-746
Abstract:
The yield stress and shear-resistant properties of crosslinking polymer gel were studied by rheological measurement.It was found that when the concentration of polymer was 2 g/L,the system showed Newton's fluid;when the concentration of polymer was 3 or 4 g/L,the system showed plastic fluid,and the yield stress was 12 or 28 Pa,respectively.The retention value of viscosity of 4 g/L HPAM system was more than those of other systems.When the concentrations of the crosslinking agents were 0.25,0.5,1.0 and 1.5 mmol/L,respectively,the yield stresses were 6.0,20.0,12.0 and 2.0 Pa,respectively.When the pH value of the system was 4.86,the system showed Newton's fluid;when the pH values of the system were 5.60 and 6.46,the system showed Newton's fluid and the yield stresses were 12 and 7 Pa respectively.The strong gels exhibit higher viscosity retention,i.e.higher shear-resistant properties.
The yield stress and shear-resistant properties of crosslinking polymer gel were studied by rheological measurement.It was found that when the concentration of polymer was 2 g/L,the system showed Newton's fluid;when the concentration of polymer was 3 or 4 g/L,the system showed plastic fluid,and the yield stress was 12 or 28 Pa,respectively.The retention value of viscosity of 4 g/L HPAM system was more than those of other systems.When the concentrations of the crosslinking agents were 0.25,0.5,1.0 and 1.5 mmol/L,respectively,the yield stresses were 6.0,20.0,12.0 and 2.0 Pa,respectively.When the pH value of the system was 4.86,the system showed Newton's fluid;when the pH values of the system were 5.60 and 6.46,the system showed Newton's fluid and the yield stresses were 12 and 7 Pa respectively.The strong gels exhibit higher viscosity retention,i.e.higher shear-resistant properties.
2006, 23(7): 747-752
Abstract:
The inclusion interaction of perhydroxycucurbit[6] uril(HOCB6) with p-aminobenzene sulfonic acid(ABS) was studied by UV spectroscopic and fluorimetric methods.Several effect factors,such as the pH values,common organic solvents and surfactants on the fluorescent intensity and the stability of the complex were investigated.The results indicate that the hydrogen-bonding interaction between HOCB6 and ABS contributed to the formation of a 1:1 type exo-inclusion complex.The complex constant was determined to be 1.39×103 L/mol.The comparative studies of HOCB6 with other supramolecules,such as cucurbit[6] uril(CB6),β-cyclodextrin and p-(N,N-dimethylaminomethyl)-calix[8] arene,were also carried out by using ABS as guest probe.The spectral changes showed that the stable endo-inclusion complex was formed between cucurbit[6] uril and ABS through hydrophobic interaction,and the exo-inclusion complex was formed between p-(N,N-dimethylaminomethyl)-calix[8] arene and ABS through hydrogen-bonding and π-π interactions mainly.Their complex constants were determined to be 1.31×102 L/mol and 2.57×104 L/mol,respectively.While the interaction between β-cyclodextrin and ABS did not exit,which ascribed to the big cavity of β-cyclodextrin.It is noteworthy that the structure of HOCB6-ABS is different from that of its parent CB6-ABS due to the introduction of peripheral hydroxyl groups and hydrogen-bonding interaction.
The inclusion interaction of perhydroxycucurbit[6] uril(HOCB6) with p-aminobenzene sulfonic acid(ABS) was studied by UV spectroscopic and fluorimetric methods.Several effect factors,such as the pH values,common organic solvents and surfactants on the fluorescent intensity and the stability of the complex were investigated.The results indicate that the hydrogen-bonding interaction between HOCB6 and ABS contributed to the formation of a 1:1 type exo-inclusion complex.The complex constant was determined to be 1.39×103 L/mol.The comparative studies of HOCB6 with other supramolecules,such as cucurbit[6] uril(CB6),β-cyclodextrin and p-(N,N-dimethylaminomethyl)-calix[8] arene,were also carried out by using ABS as guest probe.The spectral changes showed that the stable endo-inclusion complex was formed between cucurbit[6] uril and ABS through hydrophobic interaction,and the exo-inclusion complex was formed between p-(N,N-dimethylaminomethyl)-calix[8] arene and ABS through hydrogen-bonding and π-π interactions mainly.Their complex constants were determined to be 1.31×102 L/mol and 2.57×104 L/mol,respectively.While the interaction between β-cyclodextrin and ABS did not exit,which ascribed to the big cavity of β-cyclodextrin.It is noteworthy that the structure of HOCB6-ABS is different from that of its parent CB6-ABS due to the introduction of peripheral hydroxyl groups and hydrogen-bonding interaction.
2006, 23(7): 753-756
Abstract:
With 2-phenoxyethanol as initial material,a novel pseudo-cryptand ether polymer with crosslinking phenolic chain and nitrogen atom at the end of bridge was synthesized by a combined method of first polymerization,then cyclization and functionalization.Static adsorption properties of the polymeric cryptand ether for metallic ions were tested.The results show that the polymer has a good preferential adsorption property for Fe3+ and the adsorption capacity is 1.22 mmol/g(start concentration of Fe3+:0.053 mol/L,25℃).Within the limits,the quantity of adsorption for Fe3+ increases along with the rising of Fe3+ concentration and the increase of adsorptive time,the adsorption reaches equilibrium after three hour.The polymer has a good reprocess property and it can be fully reused.The adsorption capacities were over 1.16 mmol/g after it was used more than four times.
With 2-phenoxyethanol as initial material,a novel pseudo-cryptand ether polymer with crosslinking phenolic chain and nitrogen atom at the end of bridge was synthesized by a combined method of first polymerization,then cyclization and functionalization.Static adsorption properties of the polymeric cryptand ether for metallic ions were tested.The results show that the polymer has a good preferential adsorption property for Fe3+ and the adsorption capacity is 1.22 mmol/g(start concentration of Fe3+:0.053 mol/L,25℃).Within the limits,the quantity of adsorption for Fe3+ increases along with the rising of Fe3+ concentration and the increase of adsorptive time,the adsorption reaches equilibrium after three hour.The polymer has a good reprocess property and it can be fully reused.The adsorption capacities were over 1.16 mmol/g after it was used more than four times.
2006, 23(7): 757-761
Abstract:
The UV-Vis absorption spectra of 2-[2-(5-bromo-pyridyl)azo]-5-(diethylamino) phenol(5-Br-PADAP) in various solvents were studied.It was found that both the spectra shape and peak wavelength of 5-Br-PADAP are remarkably sensitive to the nature of the solvent in which it is measured and the concentration of the dye itself.In methanol,1×10-5 mol/L of 5-Br-PADAP exhibited a dramatic red-shift in comparison with that in "normal" solvents(alcohols,water,etc.).The absorption spectra also changed with the concentration of 5-Br-PADAP,and the change trend is identical with that of resonance light scattering.The concentration where the main absorption peak changed to minor one was in accord with that where the peak of resonance light scattering appeared.The 1H NMR spectra of 5-Br-PADAP in different solvents were also quite different.The mechanism of the spectra change of 5-Br-PADAP was discussed.
The UV-Vis absorption spectra of 2-[2-(5-bromo-pyridyl)azo]-5-(diethylamino) phenol(5-Br-PADAP) in various solvents were studied.It was found that both the spectra shape and peak wavelength of 5-Br-PADAP are remarkably sensitive to the nature of the solvent in which it is measured and the concentration of the dye itself.In methanol,1×10-5 mol/L of 5-Br-PADAP exhibited a dramatic red-shift in comparison with that in "normal" solvents(alcohols,water,etc.).The absorption spectra also changed with the concentration of 5-Br-PADAP,and the change trend is identical with that of resonance light scattering.The concentration where the main absorption peak changed to minor one was in accord with that where the peak of resonance light scattering appeared.The 1H NMR spectra of 5-Br-PADAP in different solvents were also quite different.The mechanism of the spectra change of 5-Br-PADAP was discussed.
2006, 23(7): 762-765
Abstract:
Three-component photoresists were prepared from hyperbranched polyester,multifunctional acrylate monomer and photoinitiator.The hyperbranched resin had -COOH,-OH and methacryloxy groups at their chain ends.The dried resist on glass substrate showed an H~HB pencil hardness.A high sensitivity with E0~5.5×10-3 J/cm2 and a high contrast with γ~8 were obtained for the resist exposed with a mixed UV light and developed with TMAH aqueous solution.Sensitivity and contrast upon UV exposure were tunable by development solution and the amount of photoinitiator.The resist exhibited a unique linear relationship between exposure energy and etching depth.This property provides a controlling of surface profile of micro optical elements fabricated with photoresists.Microlens arrays(200 μm×200 μm) were prepared from these photoresists with a moving-mask.
Three-component photoresists were prepared from hyperbranched polyester,multifunctional acrylate monomer and photoinitiator.The hyperbranched resin had -COOH,-OH and methacryloxy groups at their chain ends.The dried resist on glass substrate showed an H~HB pencil hardness.A high sensitivity with E0~5.5×10-3 J/cm2 and a high contrast with γ~8 were obtained for the resist exposed with a mixed UV light and developed with TMAH aqueous solution.Sensitivity and contrast upon UV exposure were tunable by development solution and the amount of photoinitiator.The resist exhibited a unique linear relationship between exposure energy and etching depth.This property provides a controlling of surface profile of micro optical elements fabricated with photoresists.Microlens arrays(200 μm×200 μm) were prepared from these photoresists with a moving-mask.
2006, 23(7): 766-769
Abstract:
A novel liquid membrane system,denoted as strip dispersion hybrid liquid membrane(SDHLM),containing N902 in kerosene as carrier,was studied as the function of dodecanol concentration,pH in feed phase,volume ratio between stripping solution and organic phase,and circulating flux of feed phase or strip dispersion phase.Solvent extraction verified that 1 mol of Cu2+ ions reacted with 2 mol of carrier and formed 1 mol of the Cu(Ⅱ)-carrier complex.The experiments showed that Cu(Ⅱ) could be efficiently transported into the stripping solution by SDHLM.When pH=2 in the feed phase,the recovery of copper(Ⅱ) in the stripping phase was 93.6%,while iron(Ⅲ) was 1.83% for Cu2+/Fe3+=1.The recovery of copper(Ⅱ) in the stripping) phase was 89.8%,while zinc(Ⅱ) was 1.38% for Cu2+/Zn2+=1 after transport for 4 h.When the concentrations of Cu2+,Fe3+,Co2+,Ni2+ and Zn2+ in the feed phase(pH=1.5) were 4.52,5.07,0.442,35.7 and 1.24 g/L,respectively,the recovery of Cu2+ in the stripping phase was 81.5%,while other metal ions were below 2.10% after the transport for 6 h.Separation experiments indicated that N902 was an excellent extractant for Cu(Ⅱ).SDHLM has several advantages over SLM and ELM:increased membrane stability,improved flux,improved recovery of target species concentration,no usage of high active surfactant and demulsification) device,and reduced cost.
A novel liquid membrane system,denoted as strip dispersion hybrid liquid membrane(SDHLM),containing N902 in kerosene as carrier,was studied as the function of dodecanol concentration,pH in feed phase,volume ratio between stripping solution and organic phase,and circulating flux of feed phase or strip dispersion phase.Solvent extraction verified that 1 mol of Cu2+ ions reacted with 2 mol of carrier and formed 1 mol of the Cu(Ⅱ)-carrier complex.The experiments showed that Cu(Ⅱ) could be efficiently transported into the stripping solution by SDHLM.When pH=2 in the feed phase,the recovery of copper(Ⅱ) in the stripping phase was 93.6%,while iron(Ⅲ) was 1.83% for Cu2+/Fe3+=1.The recovery of copper(Ⅱ) in the stripping) phase was 89.8%,while zinc(Ⅱ) was 1.38% for Cu2+/Zn2+=1 after transport for 4 h.When the concentrations of Cu2+,Fe3+,Co2+,Ni2+ and Zn2+ in the feed phase(pH=1.5) were 4.52,5.07,0.442,35.7 and 1.24 g/L,respectively,the recovery of Cu2+ in the stripping phase was 81.5%,while other metal ions were below 2.10% after the transport for 6 h.Separation experiments indicated that N902 was an excellent extractant for Cu(Ⅱ).SDHLM has several advantages over SLM and ELM:increased membrane stability,improved flux,improved recovery of target species concentration,no usage of high active surfactant and demulsification) device,and reduced cost.
2006, 23(7): 770-775
Abstract:
By the reaction of chitosan with vanillin,Schiff's base was firstly obtained,followed by the eaction of NaBH4 with Schiff's base to yield water-soluble N-(4-hydroxy-3-mehtoxybenzyl) chitosan (VCS).The chemical structure of the modified chitosan VCS was characterized by FTIR,1H NMR and UV spectroscopies.Degree of substitution of N-4-hydroxy-3-mehtoxybenzyl determined with colloid titration was 2.37 mmol/g.The swelling characteristics of hydrogels(VCSG) prepared by cross-linking of glutaraldehyde with VCS were studied.The results showed that the swelling ratio(SR) of VCSG was decreased with the increasing of the dosage of glutaraldehyde.The swelling ratios of VCSG with different cross-linking degrees were decreased with the increasing of the pH value of the buffer solution between 1.2 to 7.4.The swelling ratios of VCSG were increased with the increasing of the pH value of the buffer solution between 9.0 to 11.0.The VCSG with a lower cross-linking degree swelled more significantly in a pH=1.2 buffer solution than in other medium,the VCSG with a high cross-linking degree swelled similarly and lower SR in buffer solution with different pH values.VCSG showed pH-sensitive in buffer solutions.The release behavior of famotidine entrapped in the hydrogel showed different speeds with the change of the pH value of medium in vitro.The release speeds of famotidine in VCSG in the media of pH=1.2 and 3.0 were much faster than those in the media of pH=5.0 and 7.4,both showed slow release effect.VCSG is pH sensitive and the swelling behavior of VCSG can be regulated by changing the dosage of the cross-linking agent,and has the potential as being the carrier for controlling drug release.
By the reaction of chitosan with vanillin,Schiff's base was firstly obtained,followed by the eaction of NaBH4 with Schiff's base to yield water-soluble N-(4-hydroxy-3-mehtoxybenzyl) chitosan (VCS).The chemical structure of the modified chitosan VCS was characterized by FTIR,1H NMR and UV spectroscopies.Degree of substitution of N-4-hydroxy-3-mehtoxybenzyl determined with colloid titration was 2.37 mmol/g.The swelling characteristics of hydrogels(VCSG) prepared by cross-linking of glutaraldehyde with VCS were studied.The results showed that the swelling ratio(SR) of VCSG was decreased with the increasing of the dosage of glutaraldehyde.The swelling ratios of VCSG with different cross-linking degrees were decreased with the increasing of the pH value of the buffer solution between 1.2 to 7.4.The swelling ratios of VCSG were increased with the increasing of the pH value of the buffer solution between 9.0 to 11.0.The VCSG with a lower cross-linking degree swelled more significantly in a pH=1.2 buffer solution than in other medium,the VCSG with a high cross-linking degree swelled similarly and lower SR in buffer solution with different pH values.VCSG showed pH-sensitive in buffer solutions.The release behavior of famotidine entrapped in the hydrogel showed different speeds with the change of the pH value of medium in vitro.The release speeds of famotidine in VCSG in the media of pH=1.2 and 3.0 were much faster than those in the media of pH=5.0 and 7.4,both showed slow release effect.VCSG is pH sensitive and the swelling behavior of VCSG can be regulated by changing the dosage of the cross-linking agent,and has the potential as being the carrier for controlling drug release.
2006, 23(7): 776-781
Abstract:
Via the solid-phase synthesizing method,a series of fluorine ion doped lithium vanadium oxides with the fluorine contents of 0.059%,0.19%,0.35% and 0.56%(mass fraction) was synthesized at 400℃, respectively.The experimental results show that the oxidation state of the vanadium of the fluorine ion doped lithium vanadium oxides is decreased with the increase of fluorine content in the samples and the doped lithium vanadium oxide with a fluorine content of 0.19%(mass fraction) shows a monoclinic structure of Li1.2V3O8 and exhibits a max capacity of 272 mA·h/g and has a capacity fading rate of 16% in 40 cycles.Thermal analysis,XRD and Raman analysis showed that the fluorine dopant can stabilize the crystal structure of lithium vanadium oxides.
Via the solid-phase synthesizing method,a series of fluorine ion doped lithium vanadium oxides with the fluorine contents of 0.059%,0.19%,0.35% and 0.56%(mass fraction) was synthesized at 400℃, respectively.The experimental results show that the oxidation state of the vanadium of the fluorine ion doped lithium vanadium oxides is decreased with the increase of fluorine content in the samples and the doped lithium vanadium oxide with a fluorine content of 0.19%(mass fraction) shows a monoclinic structure of Li1.2V3O8 and exhibits a max capacity of 272 mA·h/g and has a capacity fading rate of 16% in 40 cycles.Thermal analysis,XRD and Raman analysis showed that the fluorine dopant can stabilize the crystal structure of lithium vanadium oxides.
2006, 23(7): 782-785
Abstract:
The silicate oxyapatites Ca2+xLa8-x(SiO4)6O2-0.5x(x=0,0.5,1.0 and 2.0) were synthesized via a sol-gel method.The apatite phases were characterised by means of X-ray diffraction(XRD). Cell parameters a and c decreased with increasing composition parameter x.Conducting mechanism was studied via electrochemistry impedance spectroscopy(EIS),it indicated that oxygen ion migration in Ca2+xLa8-x(SiO4)6O2-0.5x was via a vacancy conduct mechanism.With increasing the amount of O2-,the conductivity is consi-derably enhanced,and activation energy is lowered;however,when the amount of O2- is 2,the conductivity is reduced,and activation energy is increased.The conductivity is almost independent of the oxygen partial pressure,this suggests that the silicate apatites are pure oxygen ionic conductors.
The silicate oxyapatites Ca2+xLa8-x(SiO4)6O2-0.5x(x=0,0.5,1.0 and 2.0) were synthesized via a sol-gel method.The apatite phases were characterised by means of X-ray diffraction(XRD). Cell parameters a and c decreased with increasing composition parameter x.Conducting mechanism was studied via electrochemistry impedance spectroscopy(EIS),it indicated that oxygen ion migration in Ca2+xLa8-x(SiO4)6O2-0.5x was via a vacancy conduct mechanism.With increasing the amount of O2-,the conductivity is consi-derably enhanced,and activation energy is lowered;however,when the amount of O2- is 2,the conductivity is reduced,and activation energy is increased.The conductivity is almost independent of the oxygen partial pressure,this suggests that the silicate apatites are pure oxygen ionic conductors.
2006, 23(7): 786-789
Abstract:
Ultra-fine WS2 powders were synthesized via an improved solid reaction method from mixed tungsten and sulfur powders with different excessive sulfur coefficients(ESC),followed by the reactions in N2 or Ar atmosphere at different temperatures.Phase composition,morphology and particle size of the resulting powders were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM) and laser diffraction method.Effects of the reaction temperature and the excessive sulfur coefficient(ESC) on the phase composition and the morphology of the resulting powders were also investigated.Furthermore,W-S powders were mixed by high energy ball milling to investigate the effects of raw materials on the performance of the synthesized WS2 powders.XRD results show that pure and hexagonal tungsten disulfides are obtained at a temperature of 650℃ and an ESC of 2.0 for the ordinary blended W-S powder mixes, but only an ESC of 1.5 is needed for the high energy ball milled W-S powder mixes at the same reaction temperature.The WS2 powder synthesized have an ultrafine particle size of 0.1~0.4 μm with a granular particle shape.It was also shown that the atmosphere has an important influence on the synthesis reaction.
Ultra-fine WS2 powders were synthesized via an improved solid reaction method from mixed tungsten and sulfur powders with different excessive sulfur coefficients(ESC),followed by the reactions in N2 or Ar atmosphere at different temperatures.Phase composition,morphology and particle size of the resulting powders were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM) and laser diffraction method.Effects of the reaction temperature and the excessive sulfur coefficient(ESC) on the phase composition and the morphology of the resulting powders were also investigated.Furthermore,W-S powders were mixed by high energy ball milling to investigate the effects of raw materials on the performance of the synthesized WS2 powders.XRD results show that pure and hexagonal tungsten disulfides are obtained at a temperature of 650℃ and an ESC of 2.0 for the ordinary blended W-S powder mixes, but only an ESC of 1.5 is needed for the high energy ball milled W-S powder mixes at the same reaction temperature.The WS2 powder synthesized have an ultrafine particle size of 0.1~0.4 μm with a granular particle shape.It was also shown that the atmosphere has an important influence on the synthesis reaction.
2006, 23(7): 790-793
Abstract:
With ammonium persulfate as initiator,mixture of sodium dodecyl benzene sulfonate(SDBS) and nonionic emulsifier alkyl ethyleue oxide as compound emulsifier,an acrylic film material modified by hydroxyl silicon oil was synthesized by seeding emulsion polymerization technique.Effects of soft to hard monomers ratio,temperature,amounts of emulsifier and polysilicone on the properties of polymerization emulsion were studied.Experimental results show that the stability of polymerization emulsion was higher than others when the optimal mass ratio of soft to hard monomers was set as 13:12,and 3% emulsifiers and 12% polysilicone reacted at 75~80℃.Glass transition temperature(Tg) and water absorption of the film of modified resin are decreased dramatically and the tensile strength is increased.
With ammonium persulfate as initiator,mixture of sodium dodecyl benzene sulfonate(SDBS) and nonionic emulsifier alkyl ethyleue oxide as compound emulsifier,an acrylic film material modified by hydroxyl silicon oil was synthesized by seeding emulsion polymerization technique.Effects of soft to hard monomers ratio,temperature,amounts of emulsifier and polysilicone on the properties of polymerization emulsion were studied.Experimental results show that the stability of polymerization emulsion was higher than others when the optimal mass ratio of soft to hard monomers was set as 13:12,and 3% emulsifiers and 12% polysilicone reacted at 75~80℃.Glass transition temperature(Tg) and water absorption of the film of modified resin are decreased dramatically and the tensile strength is increased.
2006, 23(7): 794-797
Abstract:
One dimensional chain cobalt coordination polymer with α-Furoic acid,4,4'-bipyridine and cobalt carbonate was synthesized and characterized in the solvent mixture of water and methanol.It crystallized in a triclinic space group P1 with a=1.138 4(4) nm,b=1.138 4(4) nm,c=1.302 9(9) nm,γ=120.0°,V=1.462 3(12) nm3),Dc=1.612 g/cm3,Z=3,F(000)=729.R1=0.049 0,wR2=0.143 6. The crystal structure shows that the cobalt(Ⅲ) atom was coordinated with two nitrogen atoms from the two 4,4-bipys,two oxygen atoms from two α-Furoic acid molecules and two oxygen atoms from two water molecules,forming a distorted octahedral geometry.The cyclic voltametric behavior of the complex was also studied.The results showed that it was a stable complex,and there was a quasi-reversible redox process for the complex and the complex was stabilized.
One dimensional chain cobalt coordination polymer with α-Furoic acid,4,4'-bipyridine and cobalt carbonate was synthesized and characterized in the solvent mixture of water and methanol.It crystallized in a triclinic space group P1 with a=1.138 4(4) nm,b=1.138 4(4) nm,c=1.302 9(9) nm,γ=120.0°,V=1.462 3(12) nm3),Dc=1.612 g/cm3,Z=3,F(000)=729.R1=0.049 0,wR2=0.143 6. The crystal structure shows that the cobalt(Ⅲ) atom was coordinated with two nitrogen atoms from the two 4,4-bipys,two oxygen atoms from two α-Furoic acid molecules and two oxygen atoms from two water molecules,forming a distorted octahedral geometry.The cyclic voltametric behavior of the complex was also studied.The results showed that it was a stable complex,and there was a quasi-reversible redox process for the complex and the complex was stabilized.
2006, 23(7): 798-802
Abstract:
2-Ethoxycarbonyl-4,5-dimethyl-pyrrole(7) was prepared from ethylacetoacetate,ethyl formate and methyl ethyl ketone via oximination,Claisen condensation,and reductive condensation.The bromization of compound 7 gave 2-ethoxycarbonyl-3-bromo-4,5-dimethyl-pyrrole(8),which could be transferred to 2-ethoxycarbonyl-3-brome-4-methyl-5-formyl-pyrrole(9) by the formolation.In the synthesis reaction of compound 7,its yield was maximum when pH,the mole ratio of zinc to compound 1 and reaction temperature were set as 3.8,2.8:1 and 90~95℃, respectively.The effects of solvent on the bromization reaction and oxidant on the formolation reaction of the target product were studied.The results show that the optimum solvent for the bromization reaction and the optimum oxidant for the formolation reaction of the target product were carbon tetrachloride and ceric ammonium nitrate,and their yields were 86.7% and 89.3% respectively.The structures of the compounds were characterized by elemental analysis,accurate mass,1H NMR,IR and GC-MS.
2-Ethoxycarbonyl-4,5-dimethyl-pyrrole(7) was prepared from ethylacetoacetate,ethyl formate and methyl ethyl ketone via oximination,Claisen condensation,and reductive condensation.The bromization of compound 7 gave 2-ethoxycarbonyl-3-bromo-4,5-dimethyl-pyrrole(8),which could be transferred to 2-ethoxycarbonyl-3-brome-4-methyl-5-formyl-pyrrole(9) by the formolation.In the synthesis reaction of compound 7,its yield was maximum when pH,the mole ratio of zinc to compound 1 and reaction temperature were set as 3.8,2.8:1 and 90~95℃, respectively.The effects of solvent on the bromization reaction and oxidant on the formolation reaction of the target product were studied.The results show that the optimum solvent for the bromization reaction and the optimum oxidant for the formolation reaction of the target product were carbon tetrachloride and ceric ammonium nitrate,and their yields were 86.7% and 89.3% respectively.The structures of the compounds were characterized by elemental analysis,accurate mass,1H NMR,IR and GC-MS.
2006, 23(7): 803-807
Abstract:
A two-stage process was developed to synthesize the silica-based macromonomer through the surface-modification of silica with polymerizable vinyl groups. The silica surface was first treated with excess toluene-2,4-diisocynate(TDI),after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction of the above mixture with hydroxypropylacrylate(HPA).The main effecting factors on the reaction of silica with TDI were studied by determining the reaction extent of hydroxyl groups at the surface of silica particles.FTIR spectroscopy and TG were employed to characterize the macromonomer.TEM images showed that the silica particles remained unaggregated after surface modification.
A two-stage process was developed to synthesize the silica-based macromonomer through the surface-modification of silica with polymerizable vinyl groups. The silica surface was first treated with excess toluene-2,4-diisocynate(TDI),after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction of the above mixture with hydroxypropylacrylate(HPA).The main effecting factors on the reaction of silica with TDI were studied by determining the reaction extent of hydroxyl groups at the surface of silica particles.FTIR spectroscopy and TG were employed to characterize the macromonomer.TEM images showed that the silica particles remained unaggregated after surface modification.
2006, 23(7): 808-811
Abstract:
The electrochemical reduction of 2-nitropropane to N-iso-propylhydroxylamine in sulfuric acid was investigated by linear scanning and cyclic voltammogram measurements.The results show that the Cu,Ni,Pb,graphite and Cu-Hg electrodes exhibit good electrochemical activities for 2-nitropropane reduction and the peak potentials are at -0.54,-0.56,-0.55,-0.64 and-0.9 V(vs.SCE), respectively.When the preparative electrolyses were conducted at a current density of 1 000 A/cm2,the product yields and current efficiency obtained were higher than 85% and 67%,respectively.The Pb electrode was found to be the most suitable cathode material,which presented a yield of about 90% and a current efficiency of over 80%.The electrochemical reduction of 2-nitropropane on the Pb electrode is controlled by the diffusion process.
The electrochemical reduction of 2-nitropropane to N-iso-propylhydroxylamine in sulfuric acid was investigated by linear scanning and cyclic voltammogram measurements.The results show that the Cu,Ni,Pb,graphite and Cu-Hg electrodes exhibit good electrochemical activities for 2-nitropropane reduction and the peak potentials are at -0.54,-0.56,-0.55,-0.64 and-0.9 V(vs.SCE), respectively.When the preparative electrolyses were conducted at a current density of 1 000 A/cm2,the product yields and current efficiency obtained were higher than 85% and 67%,respectively.The Pb electrode was found to be the most suitable cathode material,which presented a yield of about 90% and a current efficiency of over 80%.The electrochemical reduction of 2-nitropropane on the Pb electrode is controlled by the diffusion process.
2006, 23(7): 812-814
Abstract:
The dehydration of 2-(4'-ethylbenzoyl) benzoic acid(BE acid) into 2-ethylanthraquinone(2-EAQ) was investigated over H-Beta catalyst modified by citric acid.Different feed-in methods and the reaction conditions were studied in detail.Under optimized conditions,the conversion of BE acid could reach 99.5%,and the selectivity to 2-EAQ was up to 99.0%.The results show that the H-Beta zeolite can be considered as an efficient catalyst for the substitute of concentrate H2SO4 or oleum catalyst for the dehydration of BE acid to 2-ethylanthraquinone.
The dehydration of 2-(4'-ethylbenzoyl) benzoic acid(BE acid) into 2-ethylanthraquinone(2-EAQ) was investigated over H-Beta catalyst modified by citric acid.Different feed-in methods and the reaction conditions were studied in detail.Under optimized conditions,the conversion of BE acid could reach 99.5%,and the selectivity to 2-EAQ was up to 99.0%.The results show that the H-Beta zeolite can be considered as an efficient catalyst for the substitute of concentrate H2SO4 or oleum catalyst for the dehydration of BE acid to 2-ethylanthraquinone.
2006, 23(7): 815-817
Abstract:
Polyvinyl chloride triethylene tetraamine palladium complex(PVC-TETA-Pd) was prepared,and its catalytic property for Suzuki reaction under different conditions was discussed.The results showed that this complex could catalyze the Suzuki reaction of sodium tetraphenylborate with iodobenzene to form biphenyl in air.The reaction conditions were optimized,i.e.,NaHCO3was used as base and a mixture with a ratio of V(DMF):)V(H2O) being 2:1 was used as solvent.This complex can be reused for several times.
Polyvinyl chloride triethylene tetraamine palladium complex(PVC-TETA-Pd) was prepared,and its catalytic property for Suzuki reaction under different conditions was discussed.The results showed that this complex could catalyze the Suzuki reaction of sodium tetraphenylborate with iodobenzene to form biphenyl in air.The reaction conditions were optimized,i.e.,NaHCO3was used as base and a mixture with a ratio of V(DMF):)V(H2O) being 2:1 was used as solvent.This complex can be reused for several times.
2006, 23(7): 818-820
Abstract:
The binding among Co(phen)32+,prulifloxacin and calf thymus DNA in Tris buffer solution(pH=7.4) were investigated by means of cyclic voltammetry and UV spectroscopy.The UV results showed prulifloxacin and Co(phen)32+ formed a binary complex with a binding constant of 2.0×104 L/mol.After adding DNA,the binary complex continued to combine with DNA.The electrochemical results indicated that the peak current decreased in the presence of DNA;the peak potential difference was increased by 17 mV;formal potential shifted 3.5 mV negatively.The results show that the binding mode of Co(phen)32+-prulifloxacin binary complex and DNA was mainly electrostatic interaction.
The binding among Co(phen)32+,prulifloxacin and calf thymus DNA in Tris buffer solution(pH=7.4) were investigated by means of cyclic voltammetry and UV spectroscopy.The UV results showed prulifloxacin and Co(phen)32+ formed a binary complex with a binding constant of 2.0×104 L/mol.After adding DNA,the binary complex continued to combine with DNA.The electrochemical results indicated that the peak current decreased in the presence of DNA;the peak potential difference was increased by 17 mV;formal potential shifted 3.5 mV negatively.The results show that the binding mode of Co(phen)32+-prulifloxacin binary complex and DNA was mainly electrostatic interaction.
