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2003 Volume 20 Issue 5
2003, 20(5): 409-414
Abstract:
Recent progress of supercritical fluid extraction (SFE) technology in nuclear waste management is reviewed in four topics:A.synergistic extraction of lanthanide and actinide elements using a mixture of chelating agents,e.q.tributylphosphate and a fluorinated β-diketone,B.extraction of strontium and cesium elements,C.separation extraction of mixed nuclear waste samples and D.potentical applications.The first topic is discussed in more detail.
Recent progress of supercritical fluid extraction (SFE) technology in nuclear waste management is reviewed in four topics:A.synergistic extraction of lanthanide and actinide elements using a mixture of chelating agents,e.q.tributylphosphate and a fluorinated β-diketone,B.extraction of strontium and cesium elements,C.separation extraction of mixed nuclear waste samples and D.potentical applications.The first topic is discussed in more detail.
2003, 20(5): 415-419
Abstract:
Recent researches on chemical-mechanical polishing (CMP) technology are reviewed,which include the advancements of CMP experimental methods,the characterization of the polishing effectiveness,the developments of CMP equipments and expendables.The troubles occurred in CMP technology are analyzed and some suggestions are proposed.It is concluded that establishment of a quantitative CMP rate equation is one of the key points in carring out the in-situ terminal checkout.
Recent researches on chemical-mechanical polishing (CMP) technology are reviewed,which include the advancements of CMP experimental methods,the characterization of the polishing effectiveness,the developments of CMP equipments and expendables.The troubles occurred in CMP technology are analyzed and some suggestions are proposed.It is concluded that establishment of a quantitative CMP rate equation is one of the key points in carring out the in-situ terminal checkout.
2003, 20(5): 420-423
Abstract:
A photolysis catalyst consisted of nano-titania was prepared from TiOSO4 and TiOCl2.The contents of anatase and rutile in the nano-titania were about 85% and 15%,respectively.Doping of 0.5% (mass fraction) silver on the surface of the nano-titania potentiated the catalytic activity and prolonged the life of the catalyst.Its peculiar flocculation behavior was of great benefit to the separation of the catalyst for the repeated use.The nano-titania (doped or undoped) exibited activity for photocatalytical degradation of reactive black as simulated wastewater,anthraquinone dyes in the actual wastewater,and the organic pollutants in sugar-refinery waste water.The results indicated that the silver-doped catalysts have the advantages of high activity,long life,cheapness and repeated usage.
A photolysis catalyst consisted of nano-titania was prepared from TiOSO4 and TiOCl2.The contents of anatase and rutile in the nano-titania were about 85% and 15%,respectively.Doping of 0.5% (mass fraction) silver on the surface of the nano-titania potentiated the catalytic activity and prolonged the life of the catalyst.Its peculiar flocculation behavior was of great benefit to the separation of the catalyst for the repeated use.The nano-titania (doped or undoped) exibited activity for photocatalytical degradation of reactive black as simulated wastewater,anthraquinone dyes in the actual wastewater,and the organic pollutants in sugar-refinery waste water.The results indicated that the silver-doped catalysts have the advantages of high activity,long life,cheapness and repeated usage.
2003, 20(5): 424-428
Abstract:
The quasi-three-component phase diagrams of microemulsion system composed of AS/CTAB/alcohol/n-C7H16/H2O and SDS/CTAB/alcohol/n-C7H16/H2O have been used to investigate the formation of middle phase microemulsion as function of the kinds of salt and alcohols.It is found that alcohol plays a significant role in formation of microemulsion (ME) and middle phase microemulsion (MPME);and the alcohol mixture such as n-C3H7OH+n-C4H9OH and i-C3H7OH+n-C4H9OH are superior in microemulsion formation to the single ones;as to the effect of salts,the protosalt appears more favourable.
The quasi-three-component phase diagrams of microemulsion system composed of AS/CTAB/alcohol/n-C7H16/H2O and SDS/CTAB/alcohol/n-C7H16/H2O have been used to investigate the formation of middle phase microemulsion as function of the kinds of salt and alcohols.It is found that alcohol plays a significant role in formation of microemulsion (ME) and middle phase microemulsion (MPME);and the alcohol mixture such as n-C3H7OH+n-C4H9OH and i-C3H7OH+n-C4H9OH are superior in microemulsion formation to the single ones;as to the effect of salts,the protosalt appears more favourable.
2003, 20(5): 429-432
Abstract:
Effects of the organic solvents,concentration of the extractant and temperature on the formation of the third phase in Cyanex 923-H2SO4-H2O system have been investigated.For the linear alkane solvents,the more the carbon number of the alkane,the easier the third phase occurs.The greater the polarizability of the solvent,the more difficult the third phase appears,and it does not even appear.High extractant concentration and high temperature are helpless in the formation of the third phase.The formation of three-phase system could be a favourable opportunity for purification of the extractant.
Effects of the organic solvents,concentration of the extractant and temperature on the formation of the third phase in Cyanex 923-H2SO4-H2O system have been investigated.For the linear alkane solvents,the more the carbon number of the alkane,the easier the third phase occurs.The greater the polarizability of the solvent,the more difficult the third phase appears,and it does not even appear.High extractant concentration and high temperature are helpless in the formation of the third phase.The formation of three-phase system could be a favourable opportunity for purification of the extractant.
2003, 20(5): 433-436
Abstract:
Anatase TiO2 nanotubes were prepared from tetrabutyl titanate (Ti(OC4H9)4) using porous alumina as a template.The nanotubes exhibited uniform diameter,but rough walls and consisted of small crystals.They manifest high photocatalytic activity in the degradation of sodium dodecyl benzene sulfonate (SDBS) with bubbling air.About 30% SDBS was degraded under 20 min irradiation.UV-vis spectra and the structure identification revealed that the TiO2 nanotubes have greater energy gap,less possibility for the combination of electron-hole pairs,to give stronger redox ability and higher photocatalytic activity than TiO2 film.
Anatase TiO2 nanotubes were prepared from tetrabutyl titanate (Ti(OC4H9)4) using porous alumina as a template.The nanotubes exhibited uniform diameter,but rough walls and consisted of small crystals.They manifest high photocatalytic activity in the degradation of sodium dodecyl benzene sulfonate (SDBS) with bubbling air.About 30% SDBS was degraded under 20 min irradiation.UV-vis spectra and the structure identification revealed that the TiO2 nanotubes have greater energy gap,less possibility for the combination of electron-hole pairs,to give stronger redox ability and higher photocatalytic activity than TiO2 film.
2003, 20(5): 437-442
Abstract:
Layered sodium manganese oxide Na0.67[Mn0.90Mg0.10]MgO2 was prepared by solid state reaction,and the kinetics of ion exchange intercalation reaction of Li+ into layered sodium manganese oxide was studied.The reaction has been investigated in two systems:n-hexanol solution system and molten salt system.The apparent rate constant、reaction order and activation energy of the ion exchange reaction were calculated.An intercalation kinetic model has been used in the study on ion exchange intercalation reaction.The concentration changes of the precursor and product were monitored according to 2θ angle of [002] peak in powder XRD patterns.The rate constants in molten salt were calculated to be 0.127~0.208 s-1(260~300℃),much greater than those in n-hexanol solution system,5.93×10-4~3.94×10-3 s-1(40~80℃).The reaction orders for the two systems are all about 1.The calculated values of the apparent activation energy are 31.2 kJ/mol (for molten salt) and 43.7 kJ/mol (for n-hexanol solution),respectively.
Layered sodium manganese oxide Na0.67[Mn0.90Mg0.10]MgO2 was prepared by solid state reaction,and the kinetics of ion exchange intercalation reaction of Li+ into layered sodium manganese oxide was studied.The reaction has been investigated in two systems:n-hexanol solution system and molten salt system.The apparent rate constant、reaction order and activation energy of the ion exchange reaction were calculated.An intercalation kinetic model has been used in the study on ion exchange intercalation reaction.The concentration changes of the precursor and product were monitored according to 2θ angle of [002] peak in powder XRD patterns.The rate constants in molten salt were calculated to be 0.127~0.208 s-1(260~300℃),much greater than those in n-hexanol solution system,5.93×10-4~3.94×10-3 s-1(40~80℃).The reaction orders for the two systems are all about 1.The calculated values of the apparent activation energy are 31.2 kJ/mol (for molten salt) and 43.7 kJ/mol (for n-hexanol solution),respectively.
2003, 20(5): 443-446
Abstract:
Copolymer nanoparticles was prepared from 2,5-dimercapto-1,3,4-thiadiazole and toluene-2,4-di-iso-cyanate and characterized by HRTEM、FTIR、TG and DTA techniques.The tribological properties of the nanoparticles as an additive in water were evaluated in a four-ball tester.The morphologies on the worn surfaces of the lubricated GCr15 steel were investigated by means of SEM.Experiment results revealed that tribological performance is highly improved when the copolymer is used as lubricant additive in water.
Copolymer nanoparticles was prepared from 2,5-dimercapto-1,3,4-thiadiazole and toluene-2,4-di-iso-cyanate and characterized by HRTEM、FTIR、TG and DTA techniques.The tribological properties of the nanoparticles as an additive in water were evaluated in a four-ball tester.The morphologies on the worn surfaces of the lubricated GCr15 steel were investigated by means of SEM.Experiment results revealed that tribological performance is highly improved when the copolymer is used as lubricant additive in water.
2003, 20(5): 447-451
Abstract:
The solution polymerization and bulk precipitation polymerization of isoprene with supported titanium catalyst TiCl4/MgCl2-Al(i-Bu)3 using hydrogen as relative molecular mass modifier have been carried out in order to synthesis low relative molecular mass trans-1,4-polyisoprene wax (LMTPIW).The effects of hydrogen pressure,n(Al)/n(Ti),n(Ti)/n(Ip),and polymerization time and temperature on the relative molecular mass,catalyst efficiency and structure of polymer were studied.Increasing the hydrogen pressure results in the decrease of intrinsic viscosity of the polymer [η].The [η],viscosity average relative molecular mass and number average relative molecular mass were found to be decreased to 0.23 dL/g,3800 and 1000,respectively,when H2 pressure was increased to 2.4 MPa.The x(trans-1,4-unit) in the polymer was over 92%.The crystallinity of the polymer was ca.30% with Tm being 50~55℃.The relative molecular mass distribution index (ID) was 50~80.
The solution polymerization and bulk precipitation polymerization of isoprene with supported titanium catalyst TiCl4/MgCl2-Al(i-Bu)3 using hydrogen as relative molecular mass modifier have been carried out in order to synthesis low relative molecular mass trans-1,4-polyisoprene wax (LMTPIW).The effects of hydrogen pressure,n(Al)/n(Ti),n(Ti)/n(Ip),and polymerization time and temperature on the relative molecular mass,catalyst efficiency and structure of polymer were studied.Increasing the hydrogen pressure results in the decrease of intrinsic viscosity of the polymer [η].The [η],viscosity average relative molecular mass and number average relative molecular mass were found to be decreased to 0.23 dL/g,3800 and 1000,respectively,when H2 pressure was increased to 2.4 MPa.The x(trans-1,4-unit) in the polymer was over 92%.The crystallinity of the polymer was ca.30% with Tm being 50~55℃.The relative molecular mass distribution index (ID) was 50~80.
Iufluence of the Structure of Supported Fe-based Perovskite-type Oxide Catalyst on the SO2 Reduction
2003, 20(5): 452-457
Abstract:
The structure and property of γ-Al2O3 supported Fe-based perovskite-type oxide catalysts were studied.Doping with Cu2+、Co3+ in B-site could improve the redox property of catalysts,but the catalytic activity in SO2 reduction was decreased due to the strong adsorption of SO2,meanwhile,the oxidation of CO was hindered.Substitution of La with Sr decreases the catalyst redox property and SO2 reduction activity,as the defects change to ordered sequence.XRD result revealed that the ABO3 framework could be maintained in the reaction,so the ABO3 structure was regard as the active phase.XPS results also indicated that different kind of metal sulfide species shows different effect on the reaction.
The structure and property of γ-Al2O3 supported Fe-based perovskite-type oxide catalysts were studied.Doping with Cu2+、Co3+ in B-site could improve the redox property of catalysts,but the catalytic activity in SO2 reduction was decreased due to the strong adsorption of SO2,meanwhile,the oxidation of CO was hindered.Substitution of La with Sr decreases the catalyst redox property and SO2 reduction activity,as the defects change to ordered sequence.XRD result revealed that the ABO3 framework could be maintained in the reaction,so the ABO3 structure was regard as the active phase.XPS results also indicated that different kind of metal sulfide species shows different effect on the reaction.
2003, 20(5): 458-461
Abstract:
FeTPP-Pt/C co-catalysts were prepared by a balance-adsorption method.The activity for oxygen reduction reaction (ORR) and methanol-tolerant ability of heat-treated FeTPP-Pt/C and Pt/C were compared.The results showed the methanol-tolerant ability of Pt/C was improved by heat-treatment.Heat-treated FeTPP-Pt/C co-catalysts owned higher activity for ORR and better methanol-tolerant ability,especially FeTPP-Pt/C heat-treated at 700℃ has the highest activity for ORR.
FeTPP-Pt/C co-catalysts were prepared by a balance-adsorption method.The activity for oxygen reduction reaction (ORR) and methanol-tolerant ability of heat-treated FeTPP-Pt/C and Pt/C were compared.The results showed the methanol-tolerant ability of Pt/C was improved by heat-treatment.Heat-treated FeTPP-Pt/C co-catalysts owned higher activity for ORR and better methanol-tolerant ability,especially FeTPP-Pt/C heat-treated at 700℃ has the highest activity for ORR.
2003, 20(5): 462-465
Abstract:
Polyimide/TiO2 nano-composite membranes for gas separation were prepared by a sol-gel method.The structure of the composite was characterized by FT-IR,SEM,TEM and UV-Vis measurements.Its chemical resistance and permeability towards H2,N2 and CH4 were examined.The results showed the existence of chemical bindings between TiO2 and the polyimide.The size of TiO2 was about 10 nm in the composite with TiO2 content of 22.3% (mass fraction) and the composite was still transparent when TiO2 amounted to 27.2% (mass fraction).The quantum size effect occurred in UV-Vis spectra of the composites.The chemical resistance and the gas permeability of the composites were greatly improved as compared with that of the pure polyimide.The H2 permeability of the composite membrane containing 27.2% of TiO2 increased to 1.061×10-14 m3·m/(m2·s·Pa) (the initial value was 2.857×10-15 m3·m/(m2·s·Pa)) and the ideal selectivity coefficients of H2/N2 and H2/CH4 were 187.5 and 143.2,respectively.
Polyimide/TiO2 nano-composite membranes for gas separation were prepared by a sol-gel method.The structure of the composite was characterized by FT-IR,SEM,TEM and UV-Vis measurements.Its chemical resistance and permeability towards H2,N2 and CH4 were examined.The results showed the existence of chemical bindings between TiO2 and the polyimide.The size of TiO2 was about 10 nm in the composite with TiO2 content of 22.3% (mass fraction) and the composite was still transparent when TiO2 amounted to 27.2% (mass fraction).The quantum size effect occurred in UV-Vis spectra of the composites.The chemical resistance and the gas permeability of the composites were greatly improved as compared with that of the pure polyimide.The H2 permeability of the composite membrane containing 27.2% of TiO2 increased to 1.061×10-14 m3·m/(m2·s·Pa) (the initial value was 2.857×10-15 m3·m/(m2·s·Pa)) and the ideal selectivity coefficients of H2/N2 and H2/CH4 were 187.5 and 143.2,respectively.
2003, 20(5): 466-469
Abstract:
The formation and the structure of the unique piled lamellae rows in hard elastic polypropylene have been studied by WAXD and SAXS techniques.The results show that lamellae rows are parallel to each other and perpendicular to the extrusion direction when polypropylene melt crystallized under stress field.And the higher the melting temperature of polypropylene sample,the higher melt draft-ratio is required for piling up.The results also show that lam ellar thickness in polypropylene is increased under higher melt draft ratio,and decreased with increase of melt temperature.The lamellar thickness is increased drastically when annealing temperature is between 110℃ to 120℃.
The formation and the structure of the unique piled lamellae rows in hard elastic polypropylene have been studied by WAXD and SAXS techniques.The results show that lamellae rows are parallel to each other and perpendicular to the extrusion direction when polypropylene melt crystallized under stress field.And the higher the melting temperature of polypropylene sample,the higher melt draft-ratio is required for piling up.The results also show that lam ellar thickness in polypropylene is increased under higher melt draft ratio,and decreased with increase of melt temperature.The lamellar thickness is increased drastically when annealing temperature is between 110℃ to 120℃.
2003, 20(5): 470-473
Abstract:
Ni(acac)2·2H2O was encapsulated in SiO2 by a Sol-gel method and used in epoxidation of cyclohexene.The catalysts were characterized by FT-IR spectroscopy and BET.The best encapsulation conditions were pH=3,n(H2O)/n(Si)=6,drying temperature 80℃.The activity of the encapsulated Ni(acac)2 catalyst decreased not much after 3 experiments.The prepared encapsulated catalyst has the advantages of avoiding corrosion of apparatus,regeneration and high yield of epoxide of cyclohexene (ECH) as compared with encapsulated Fe(acac)3 and Co(acac)2·2H2O.
Ni(acac)2·2H2O was encapsulated in SiO2 by a Sol-gel method and used in epoxidation of cyclohexene.The catalysts were characterized by FT-IR spectroscopy and BET.The best encapsulation conditions were pH=3,n(H2O)/n(Si)=6,drying temperature 80℃.The activity of the encapsulated Ni(acac)2 catalyst decreased not much after 3 experiments.The prepared encapsulated catalyst has the advantages of avoiding corrosion of apparatus,regeneration and high yield of epoxide of cyclohexene (ECH) as compared with encapsulated Fe(acac)3 and Co(acac)2·2H2O.
2003, 20(5): 474-478
Abstract:
Superoxide dismutase (SOD) separated and extracted from ryegrass leaves (Lolium perenneperennial) was purified by fraction precipitation by ammonium sulfate and column chromatography.The purified enzyme is found to be a copper/zinc superoxide dismutase as assayed by its sensitivity to KCN and H2O2.Electrophoretic analysis indicated that the enzyme contains two homogenous subunits with molecular weight of 15900 with N-terminal being alanine and maximum ultraviolet absorption at 254 nm.The SOD from ryegrass leaves is thermal stable with activity loss of 27% at 65℃ for an hour.Quantitative analysis of amino acids revealed that this protein was composed of 212 amino acids and lack of tryptophan.
Superoxide dismutase (SOD) separated and extracted from ryegrass leaves (Lolium perenneperennial) was purified by fraction precipitation by ammonium sulfate and column chromatography.The purified enzyme is found to be a copper/zinc superoxide dismutase as assayed by its sensitivity to KCN and H2O2.Electrophoretic analysis indicated that the enzyme contains two homogenous subunits with molecular weight of 15900 with N-terminal being alanine and maximum ultraviolet absorption at 254 nm.The SOD from ryegrass leaves is thermal stable with activity loss of 27% at 65℃ for an hour.Quantitative analysis of amino acids revealed that this protein was composed of 212 amino acids and lack of tryptophan.
2003, 20(5): 479-482
Abstract:
The molybdovanadophosphate nanoparticles with Dawson structure (NH4)8P2Mo16V2O62·7H2O were synthesized by solid-state reaction at room temperature and characterized by elemental analysis,IR,XRD,TEM,TG-DTA and BET techniques.The nanoparticles are found still to exhibite Dawson structure with average size being 22 nm and BET area 167 m2/g.They are stable at temperature<441℃.
The molybdovanadophosphate nanoparticles with Dawson structure (NH4)8P2Mo16V2O62·7H2O were synthesized by solid-state reaction at room temperature and characterized by elemental analysis,IR,XRD,TEM,TG-DTA and BET techniques.The nanoparticles are found still to exhibite Dawson structure with average size being 22 nm and BET area 167 m2/g.They are stable at temperature<441℃.
2003, 20(5): 483-486
Abstract:
The active phases of electrodes were characterized by XRD,SEM and surface area measurement.It was found that the active phase of PbO2/Ti electrode contains more β-PbO2 and possesses larger specific surface area than that of PbO2/Pb electrode.The electrochemical parameters in the oxidation process of Cr2(SO4)3 were determined by steady-state polarization curve.The current efficiency of PbO2/Pb and PbO2/Ti electrodes in the preparation of dichromic acid by electrooxidation chromium sulfate and stability of the electrodes were investigated.The results showed that the PbO2/Ti electrode exhibited better electrocatalytic activity and electrochemical stability than PbO2/Pb electrode in the course of 800 h test.
The active phases of electrodes were characterized by XRD,SEM and surface area measurement.It was found that the active phase of PbO2/Ti electrode contains more β-PbO2 and possesses larger specific surface area than that of PbO2/Pb electrode.The electrochemical parameters in the oxidation process of Cr2(SO4)3 were determined by steady-state polarization curve.The current efficiency of PbO2/Pb and PbO2/Ti electrodes in the preparation of dichromic acid by electrooxidation chromium sulfate and stability of the electrodes were investigated.The results showed that the PbO2/Ti electrode exhibited better electrocatalytic activity and electrochemical stability than PbO2/Pb electrode in the course of 800 h test.
2003, 20(5): 487-490
Abstract:
Ehyl N-imidazolyl acetate (IEA) was synthesized from imidazole and ethyl chloro acetate and characterized by IR spectrum.The corrosion-inhibition function of IEA towards copper in Na2SO4 and NaHCO3 solutions were examined by polarization curves and AC impedance measurements.The results revealed that in 5 mg/L solution of 3% (mass fraction) NaHCO3 or Na2SO4 at 15℃ IEA showed an inhibition efficiency of 86.8% and 92.7%,respectively,towards copper electrode.IEA had lower use level and better corrosion-inhibition efficiency than imidazole.
Ehyl N-imidazolyl acetate (IEA) was synthesized from imidazole and ethyl chloro acetate and characterized by IR spectrum.The corrosion-inhibition function of IEA towards copper in Na2SO4 and NaHCO3 solutions were examined by polarization curves and AC impedance measurements.The results revealed that in 5 mg/L solution of 3% (mass fraction) NaHCO3 or Na2SO4 at 15℃ IEA showed an inhibition efficiency of 86.8% and 92.7%,respectively,towards copper electrode.IEA had lower use level and better corrosion-inhibition efficiency than imidazole.
2003, 20(5): 491-492
Abstract:
A new process of electroless plating of nickel on glass substrate without using conventional palladium choride solution activator has been developed.The activation solution consists of nickel acetate,citric acid,and methanol.Heat treatment process of activation solution has been monitored by DTA-TGA and XRD.The results show that the activation solution was completely decomposed into hexagonal Ni and cubic NiO at 310℃.The amorphous electroless deposits was determined by XRD and it contains Ni 88.4% and P 11.6% (mass fraction) by chemical analysis.
A new process of electroless plating of nickel on glass substrate without using conventional palladium choride solution activator has been developed.The activation solution consists of nickel acetate,citric acid,and methanol.Heat treatment process of activation solution has been monitored by DTA-TGA and XRD.The results show that the activation solution was completely decomposed into hexagonal Ni and cubic NiO at 310℃.The amorphous electroless deposits was determined by XRD and it contains Ni 88.4% and P 11.6% (mass fraction) by chemical analysis.
2003, 20(5): 493-495
Abstract:
The relation of the electrochemiluminescence (ECL) intensity with the shape of perforated and imperforated platinum electrodes has been investigated.ICCD (Intensified charge-coupled device) was used to get the images of ECL of Ru(bpy)3Cl2·6H2O and tripropylamine (TPA) on the electrodes.The results showed that the ECL was concentrated on the edge of the electrode.For the perforated platinum electrode,the ECL intensity was found to be dependent both on the electrode edge and the edge of the holes on the disk electrode.The ECL intensity of Ru(bpy)3Cl2·6H2O measured on the four-hole disk electrode was double higher than that measured on the simple disk electrode and the detection limit was increased approximately by three orders of magnitude from 1 fmol/L to 1 amol/L.
The relation of the electrochemiluminescence (ECL) intensity with the shape of perforated and imperforated platinum electrodes has been investigated.ICCD (Intensified charge-coupled device) was used to get the images of ECL of Ru(bpy)3Cl2·6H2O and tripropylamine (TPA) on the electrodes.The results showed that the ECL was concentrated on the edge of the electrode.For the perforated platinum electrode,the ECL intensity was found to be dependent both on the electrode edge and the edge of the holes on the disk electrode.The ECL intensity of Ru(bpy)3Cl2·6H2O measured on the four-hole disk electrode was double higher than that measured on the simple disk electrode and the detection limit was increased approximately by three orders of magnitude from 1 fmol/L to 1 amol/L.
2003, 20(5): 496-498
Abstract:
The technological process of preparation of colloid Sb2O5 by oxidation of Sb2O3 with hydrogen peroxide using borax as a stabilizer has been investigated.The optimum preparation conditions selected by orthogonal factorization method as follows m(H2O):m(Sb2O3)=7.5:1,n(H2O2):n(Sb2O3)=3:1,m(Na2B4O7·10H2O):m(Sb2O3)=11:0,95℃,1.5 h.The conversion of Sb2O3>95%,light transmittance of colloid >85% and the average diameter of Sb2O5 particles was 50 nm.The colloid Sb2O5 prepared was storage stable without coagulation for more than one year.
The technological process of preparation of colloid Sb2O5 by oxidation of Sb2O3 with hydrogen peroxide using borax as a stabilizer has been investigated.The optimum preparation conditions selected by orthogonal factorization method as follows m(H2O):m(Sb2O3)=7.5:1,n(H2O2):n(Sb2O3)=3:1,m(Na2B4O7·10H2O):m(Sb2O3)=11:0,95℃,1.5 h.The conversion of Sb2O3>95%,light transmittance of colloid >85% and the average diameter of Sb2O5 particles was 50 nm.The colloid Sb2O5 prepared was storage stable without coagulation for more than one year.
2003, 20(5): 499-501
Abstract:
A new method on fabrication of cobalt hexacyanoferrate modified glassy carbon (CoHCF/GC) electrode is described.The method is easy to manipulate and control the coverage of CoHCF on the surface of the GC electrode.The CoHCF/GC electrode shows electrocatalytic activity towards the redox reaction of dopamine (DA) in the phosphate buffer solution with a decreasing of the overpotential of 140 mV.The reaction rate constant of the dopamine oxidation at the CoHCF/GC electrode is determined with rotating disk electrode measurements.
A new method on fabrication of cobalt hexacyanoferrate modified glassy carbon (CoHCF/GC) electrode is described.The method is easy to manipulate and control the coverage of CoHCF on the surface of the GC electrode.The CoHCF/GC electrode shows electrocatalytic activity towards the redox reaction of dopamine (DA) in the phosphate buffer solution with a decreasing of the overpotential of 140 mV.The reaction rate constant of the dopamine oxidation at the CoHCF/GC electrode is determined with rotating disk electrode measurements.
2003, 20(5): 502-504
Abstract:
Amphithatic polymeric microparticles were prepared from copolymers of poly (alkyl cyanoacrylate) (PACA) and poly (ethylene glycol) (PEG) (PACA-co-PEG) by evaporation method.And drug-loaded copolymeric microparticles were formed by mixing polymeric microparticles with paracetamol (PCTM) as a simulated drug.The polymeric microparticles are round shaped with outer diameter <200 nm as determined by dynamic light scattering and transmission electron microscopy.The degradation rate of PECA-co-PEG was less than that of homopolymer PECA;while degradation rate of PECA was larger than that of PBCA (PECA:polyethyl cyanoacrylate;PBCA:polybutyl cyanoacrylate).
Amphithatic polymeric microparticles were prepared from copolymers of poly (alkyl cyanoacrylate) (PACA) and poly (ethylene glycol) (PEG) (PACA-co-PEG) by evaporation method.And drug-loaded copolymeric microparticles were formed by mixing polymeric microparticles with paracetamol (PCTM) as a simulated drug.The polymeric microparticles are round shaped with outer diameter <200 nm as determined by dynamic light scattering and transmission electron microscopy.The degradation rate of PECA-co-PEG was less than that of homopolymer PECA;while degradation rate of PECA was larger than that of PBCA (PECA:polyethyl cyanoacrylate;PBCA:polybutyl cyanoacrylate).
2003, 20(5): 505-507
Abstract:
Cellulose-tris (3,5-dimethylphenylcarbamate)(CDMPC) was prepared and coated onto an aminopropylated mesopore spherical silica gel.The final product was used as the chiral stationary phase in high performance liquid chromatography for enantioseparation.The enantiomers of Flamprop-methyl were resoluted directly on this kind of chiral stationary phase (CSP) with a mixture of hexane and 2-propanol as a mobile phase.The effects of concentration of 2-propanol in the mobile phase on the retention and resolution were investigated.The structural features of the solutes that influence chiral separation and the chiral recognition mechanism and the eluted sequence were discussed.
Cellulose-tris (3,5-dimethylphenylcarbamate)(CDMPC) was prepared and coated onto an aminopropylated mesopore spherical silica gel.The final product was used as the chiral stationary phase in high performance liquid chromatography for enantioseparation.The enantiomers of Flamprop-methyl were resoluted directly on this kind of chiral stationary phase (CSP) with a mixture of hexane and 2-propanol as a mobile phase.The effects of concentration of 2-propanol in the mobile phase on the retention and resolution were investigated.The structural features of the solutes that influence chiral separation and the chiral recognition mechanism and the eluted sequence were discussed.
2003, 20(5): 508-510
Abstract:
Three 4-alkylcyclohexanyl acetic acids were synthesized by hydrogenation of corresponding phenyl derivatives in dioxane in yields over 93% under mild conditions.IR,H NMR and MS were used in characterization of the structure of the compounds.
Three 4-alkylcyclohexanyl acetic acids were synthesized by hydrogenation of corresponding phenyl derivatives in dioxane in yields over 93% under mild conditions.IR,H NMR and MS were used in characterization of the structure of the compounds.
