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2008 Volume 25 Issue 11
2008, 25(11): 1249-1254
Abstract:
In a pH 4.4~5.1 Britton-Robinson(BR) buffer solution,ceftriaxone sodium(CTRX) reacts with Cu(Ⅱ) and Erythrosin(Ery) to form a 1:2:3 ion-association complex,which results in the change of absor-ption spectra,the quenching of fluorescence and the great enhancement of Resonance Rayleigh Scattering(RRS),and the new RRS spectra appear.The maximum RRS wavelength is located at 329 nm.The increment of absorption,the quenching of fluorescence and the enhancement of RRS are all proportional to the CTRX concentration in a certain range.The quantitative determination ranges and the detection limits of the three methods for CTRX are 4.4×10-7~4.0×10-6 g/mL and 1.3×10-7 g/mL(spectrophotometry),2.4×10-7~1.5×10-6 g/mL and 7.2×10-8 g/mL(fluorimetry),and 2.9×10-8~2.0×10-6 g/mL and 8.8×10-9 g/mL(RRS),respectively.The optimum condition of the experiment was investigated.The composition of ion-association complex and the mechanism of reaction were discussed.Besides,the effects of some co-existing substances on the determination of CTRX by RRS were investigated.The RRS method has not only high sensitivity,but also good selectivity.It can be applied to the determination of CTRX in serum and urine samples with satisfactory results.
In a pH 4.4~5.1 Britton-Robinson(BR) buffer solution,ceftriaxone sodium(CTRX) reacts with Cu(Ⅱ) and Erythrosin(Ery) to form a 1:2:3 ion-association complex,which results in the change of absor-ption spectra,the quenching of fluorescence and the great enhancement of Resonance Rayleigh Scattering(RRS),and the new RRS spectra appear.The maximum RRS wavelength is located at 329 nm.The increment of absorption,the quenching of fluorescence and the enhancement of RRS are all proportional to the CTRX concentration in a certain range.The quantitative determination ranges and the detection limits of the three methods for CTRX are 4.4×10-7~4.0×10-6 g/mL and 1.3×10-7 g/mL(spectrophotometry),2.4×10-7~1.5×10-6 g/mL and 7.2×10-8 g/mL(fluorimetry),and 2.9×10-8~2.0×10-6 g/mL and 8.8×10-9 g/mL(RRS),respectively.The optimum condition of the experiment was investigated.The composition of ion-association complex and the mechanism of reaction were discussed.Besides,the effects of some co-existing substances on the determination of CTRX by RRS were investigated.The RRS method has not only high sensitivity,but also good selectivity.It can be applied to the determination of CTRX in serum and urine samples with satisfactory results.
2008, 25(11): 1255-1258
Abstract:
Microporous hydroxyapatite crystals were synthesized from calcium nitrate and phosphorus oxide in water/ethanol solution by hydrothermal method,and the influence of water-ethanol ratio on the crystal morphology and microstructure was explored.The composition and microstructure of the grown crystals were analyzed by XRD,FTIR,DTA/TGA,and TEM.The results show that perfect hydroxyapatite crystals with hexagonal-dipyramidal phase(60×100 nm) and micropores were obtained in V(water):V(ethanol)=1:1,and the hole density was about 3×109/cm2.The presence of micropores(1~2 nm) in the crystal planes might be important for biomedical applications as they could enhance the adhesion between the natural and synthesized bone apatite.
Microporous hydroxyapatite crystals were synthesized from calcium nitrate and phosphorus oxide in water/ethanol solution by hydrothermal method,and the influence of water-ethanol ratio on the crystal morphology and microstructure was explored.The composition and microstructure of the grown crystals were analyzed by XRD,FTIR,DTA/TGA,and TEM.The results show that perfect hydroxyapatite crystals with hexagonal-dipyramidal phase(60×100 nm) and micropores were obtained in V(water):V(ethanol)=1:1,and the hole density was about 3×109/cm2.The presence of micropores(1~2 nm) in the crystal planes might be important for biomedical applications as they could enhance the adhesion between the natural and synthesized bone apatite.
2008, 25(11): 1259-1265
Abstract:
Chloroacetylated polystyrene resin was grafted with tetraethylenepentamine or polyethylene glycol which was used to immobilize α-amylase.The immobilization process and the influence of immobilization on the catalytic characteristics of the α-amylase was investigated.It was found that the adsorption of α-amylase by PS-TEPA reached 83%(enzyme activity) and 72%(protein),and the adsorption by PS-g-PEG was 60%(enzyme activity) and 56%(protein).The use of glutaraldehyde had no positive effect on the immobilization of α-amylase.Compared to the free enzyme,the immobilized enzyme exhibited a higher affinity for the substrates,the value of vmax/Km increased from 0.024(free enzyme) to 0.035(PS-TEPA) and 0.038(PS-g-PEG),the optimum temperature was raised from 40℃(free enzyme) to 50℃(PS-TEPA) and 60℃(PS-g-PEG).The optimum pH range was also widened,from pH 7~8(free enzyme) to pH 7~10(PS-TEPA) and pH 5~8(PS-g-PEG) respectively.After washing with deionized water for 43 h,the residual adsorption of the enzyme on PS-TEPA was 1.28 times higher than that on 717 type resin,1.69 times higher than that on PS.The half life of α-amylase,t1/2,was prolonged after the immobilization,from 1 h(free enzyme) to 4.5 h(PS-TEPA) and 7.5 h(PS-g-PEG) at 70℃.
Chloroacetylated polystyrene resin was grafted with tetraethylenepentamine or polyethylene glycol which was used to immobilize α-amylase.The immobilization process and the influence of immobilization on the catalytic characteristics of the α-amylase was investigated.It was found that the adsorption of α-amylase by PS-TEPA reached 83%(enzyme activity) and 72%(protein),and the adsorption by PS-g-PEG was 60%(enzyme activity) and 56%(protein).The use of glutaraldehyde had no positive effect on the immobilization of α-amylase.Compared to the free enzyme,the immobilized enzyme exhibited a higher affinity for the substrates,the value of vmax/Km increased from 0.024(free enzyme) to 0.035(PS-TEPA) and 0.038(PS-g-PEG),the optimum temperature was raised from 40℃(free enzyme) to 50℃(PS-TEPA) and 60℃(PS-g-PEG).The optimum pH range was also widened,from pH 7~8(free enzyme) to pH 7~10(PS-TEPA) and pH 5~8(PS-g-PEG) respectively.After washing with deionized water for 43 h,the residual adsorption of the enzyme on PS-TEPA was 1.28 times higher than that on 717 type resin,1.69 times higher than that on PS.The half life of α-amylase,t1/2,was prolonged after the immobilization,from 1 h(free enzyme) to 4.5 h(PS-TEPA) and 7.5 h(PS-g-PEG) at 70℃.
2008, 25(11): 1266-1270
Abstract:
In order to develop novel high activity and low toxicity agrochemicals,a series of title compounds were synthesized by the muti-step reaction with 2-chloro-5-(chloromethyl)pyridine and 2-chloro-5-(chloro-methyl)thiazole as the starting materials,followed by the cyclization with ethyl acetoacetate,hydrolysis,halogenation and condensation with aryloxyacetyl hydrazines.Their structures were confirmed by IR,1H NMR,EI-MS and elemental analyses.Preliminary bioassays indicate that most of the target compounds possess good herbicidal activity,but do not display strong insecticidal activity.
In order to develop novel high activity and low toxicity agrochemicals,a series of title compounds were synthesized by the muti-step reaction with 2-chloro-5-(chloromethyl)pyridine and 2-chloro-5-(chloro-methyl)thiazole as the starting materials,followed by the cyclization with ethyl acetoacetate,hydrolysis,halogenation and condensation with aryloxyacetyl hydrazines.Their structures were confirmed by IR,1H NMR,EI-MS and elemental analyses.Preliminary bioassays indicate that most of the target compounds possess good herbicidal activity,but do not display strong insecticidal activity.
2008, 25(11): 1271-1276
Abstract:
To explore the role of aggregation of solid particles in stabilizing Pickering emulsions,the emulsi-fying effect of positively charged magnesium aluminum hydroxide(MAH) on paraffin/water system,the influence of sodium citrate on the aggregation of MAH as well as on the formation of MAH stabilized paraffin/water emulsion were investigated.The results show that MAH may stabilize paraffin-in-water emulsion when the initial oil-to-water volume ratio was less than 3:1.The stability of the paraffin-in-water emulsion was improved with increasing paraffin volume fraction,which was accompanied by the increase of emulsion viscosity and droplet size.At the level of less than 10%(w/w based on MAH),sodium citrate induced the aggregation of MAH particles forming open aggregates with high viscosity,which improved the stability of MAH stabilized paraffin/water emulsion.However,the viscosity of the paraffin-in-water emulsion was also increased.When denser MAH aggregates were formed by the charge neutralization of citrate,e.g.,the addition level of sodium citrate was larger than 10%,the stability of MAH stabilized paraffin-in-water emulsion was lowered and the emulsion droplet size rapidly increased.
To explore the role of aggregation of solid particles in stabilizing Pickering emulsions,the emulsi-fying effect of positively charged magnesium aluminum hydroxide(MAH) on paraffin/water system,the influence of sodium citrate on the aggregation of MAH as well as on the formation of MAH stabilized paraffin/water emulsion were investigated.The results show that MAH may stabilize paraffin-in-water emulsion when the initial oil-to-water volume ratio was less than 3:1.The stability of the paraffin-in-water emulsion was improved with increasing paraffin volume fraction,which was accompanied by the increase of emulsion viscosity and droplet size.At the level of less than 10%(w/w based on MAH),sodium citrate induced the aggregation of MAH particles forming open aggregates with high viscosity,which improved the stability of MAH stabilized paraffin/water emulsion.However,the viscosity of the paraffin-in-water emulsion was also increased.When denser MAH aggregates were formed by the charge neutralization of citrate,e.g.,the addition level of sodium citrate was larger than 10%,the stability of MAH stabilized paraffin-in-water emulsion was lowered and the emulsion droplet size rapidly increased.
2008, 25(11): 1277-1280
Abstract:
Cu/CoNiP composite wires were prepared by chemical deposition on Cu wires of 90 μm diameter.The influence of pH on the properties of the composite wires and the GMI effect was studied.It was found that pH can influence the composition and magnetic structure of the deposited layer,which affects the GMI effect of the composite wires.With the increase of pH in a certain range,the content of Ni in the deposited layer increases,and the contents of Co and P decrease.Increasing pH also results in the transformation of the magnetic deposited layer from longitudinal structure to transverse structure.The sample prepared by such a method can exhibit a maximum ΔZ/Z of 240% at 60 kHz,and it has a low critical frequency and a wide application frequency range.
Cu/CoNiP composite wires were prepared by chemical deposition on Cu wires of 90 μm diameter.The influence of pH on the properties of the composite wires and the GMI effect was studied.It was found that pH can influence the composition and magnetic structure of the deposited layer,which affects the GMI effect of the composite wires.With the increase of pH in a certain range,the content of Ni in the deposited layer increases,and the contents of Co and P decrease.Increasing pH also results in the transformation of the magnetic deposited layer from longitudinal structure to transverse structure.The sample prepared by such a method can exhibit a maximum ΔZ/Z of 240% at 60 kHz,and it has a low critical frequency and a wide application frequency range.
2008, 25(11): 1281-1285
Abstract:
TiO2/SiO2 composite material was prepared with PEG2000 as template and tetraethyl orthosilicate and tetrabutyl titanate as precursors in supercritical carbon dioxide(SC-CO2).The effect of the pressure on the impregnating ratio was studied and the product was characterized by XRD,FT-IR,nitrogen adsorption-desorption experiment and SEM.The X-ray diffraction result shows that the product is a composite of anatase TiO2 and crystal SiO2.An absorption peak appears at 935.5 cm-1,this band is ascribed to the vibration of Ti-O-Si bonds,which indicates the interaction of TiO2 and SiO2.The BET surface area calculated from the nitrogen adsorption isotherms of the product was up to 97.19 m2/g and the average pore diameter was about 2 nm.The SEM photographs of TiO2/SiO2 composite illustrate that the PEG with different molecular mass has a certain influence on the morphology of the product.
TiO2/SiO2 composite material was prepared with PEG2000 as template and tetraethyl orthosilicate and tetrabutyl titanate as precursors in supercritical carbon dioxide(SC-CO2).The effect of the pressure on the impregnating ratio was studied and the product was characterized by XRD,FT-IR,nitrogen adsorption-desorption experiment and SEM.The X-ray diffraction result shows that the product is a composite of anatase TiO2 and crystal SiO2.An absorption peak appears at 935.5 cm-1,this band is ascribed to the vibration of Ti-O-Si bonds,which indicates the interaction of TiO2 and SiO2.The BET surface area calculated from the nitrogen adsorption isotherms of the product was up to 97.19 m2/g and the average pore diameter was about 2 nm.The SEM photographs of TiO2/SiO2 composite illustrate that the PEG with different molecular mass has a certain influence on the morphology of the product.
2008, 25(11): 1286-1290
Abstract:
Eleven new thiourea derivatives were synthesized by acylchlorination and then thioureation of cinnamic acid.The structures of the new compounds were confirmed by 1H NMR,13C NMR and IR spectra and elemental analysis.Preliminary results of biological activity test indicates that some of them have certain inhibitory activity against Gibberella zeae and Rhizoctonia solani.Compound 3b exhibited 53.5% inhibition of Gibberella zeae and compound 3f exhibited 54.0% inhibition of Rhizoctonia solani at 250 mg/L.
Eleven new thiourea derivatives were synthesized by acylchlorination and then thioureation of cinnamic acid.The structures of the new compounds were confirmed by 1H NMR,13C NMR and IR spectra and elemental analysis.Preliminary results of biological activity test indicates that some of them have certain inhibitory activity against Gibberella zeae and Rhizoctonia solani.Compound 3b exhibited 53.5% inhibition of Gibberella zeae and compound 3f exhibited 54.0% inhibition of Rhizoctonia solani at 250 mg/L.
2008, 25(11): 1291-1295
Abstract:
Polystyrene/alumina was synthesized in sodium dodecyl sulphate(SDS),styrene/divinyl benzene in water with an ethanol concentration of 0.5 mol/L.The admicellar polymerization was a free radical polymerization initiated by azobisisobutyronitrile(AIBN).Effects of insoluble initiator dosage of AIBN,admicellar polymerization time and styrene concentration on the hydrophobility of the treated alumina were studied.The admicellar polymerization conditions were determined.The sodium dodecyl sulphate concentration was below its critical micelle concentration(CMC);the medium was 0.5 mol/L ethanol solution;the initiator was water insoluble AIBN;the mixing time of 24 h was determined according to the adsorption curve of sodium dodecyl sulphate on alumina;the reaction was heated to 60~70℃ in a temperature controlled water bath;polymerization time was 4 h.The results showed that the treated alumna was much more hydrophobic than the untreated one.The composite was characterized by UV-Vis,TGA,SEM and NMR.The analysis results showed that the hypothetical 'sandwich' or bilayer structure by admicellar polymerization was formed on the surface of alumina instead of the solution.
Polystyrene/alumina was synthesized in sodium dodecyl sulphate(SDS),styrene/divinyl benzene in water with an ethanol concentration of 0.5 mol/L.The admicellar polymerization was a free radical polymerization initiated by azobisisobutyronitrile(AIBN).Effects of insoluble initiator dosage of AIBN,admicellar polymerization time and styrene concentration on the hydrophobility of the treated alumina were studied.The admicellar polymerization conditions were determined.The sodium dodecyl sulphate concentration was below its critical micelle concentration(CMC);the medium was 0.5 mol/L ethanol solution;the initiator was water insoluble AIBN;the mixing time of 24 h was determined according to the adsorption curve of sodium dodecyl sulphate on alumina;the reaction was heated to 60~70℃ in a temperature controlled water bath;polymerization time was 4 h.The results showed that the treated alumna was much more hydrophobic than the untreated one.The composite was characterized by UV-Vis,TGA,SEM and NMR.The analysis results showed that the hypothetical 'sandwich' or bilayer structure by admicellar polymerization was formed on the surface of alumina instead of the solution.
2008, 25(11): 1296-1300
Abstract:
Binary compounds nano-CaCO3/HDPE,organic montmorillonite(OMMT)/HDPE and ternary composites nano-CaCO3/OMMT/HDPE were prepared by means of a twin-screw extruder.Stearic acid(SA) was used to improve the properties of nano-CaCO3.The main mechanical properties of these composites were investigated.The results show that the impact strength of nano-CaCO3(SA)/HDPE can be increased by 29.08% via adding treated nano-CaCO3,while the tensile strength of OMMT/HDPE increased by 106.4% via adding OMMT than those of HDPE itself.Most of main mechanical properties of ternary composite(nano-CaCO3/OMMT/HDPE) have been improved greatly due to the synergistic effect of organic montmorillonite with nano-CaCO3 treated by SA.Its tensile strength,Young's modulus,flexural strength,elastic modulus and impact strength of the ternary composite were increased by 124.6%,302.7%,73.86%,58.97% and 27.25% over those of HDPE,respectively.
Binary compounds nano-CaCO3/HDPE,organic montmorillonite(OMMT)/HDPE and ternary composites nano-CaCO3/OMMT/HDPE were prepared by means of a twin-screw extruder.Stearic acid(SA) was used to improve the properties of nano-CaCO3.The main mechanical properties of these composites were investigated.The results show that the impact strength of nano-CaCO3(SA)/HDPE can be increased by 29.08% via adding treated nano-CaCO3,while the tensile strength of OMMT/HDPE increased by 106.4% via adding OMMT than those of HDPE itself.Most of main mechanical properties of ternary composite(nano-CaCO3/OMMT/HDPE) have been improved greatly due to the synergistic effect of organic montmorillonite with nano-CaCO3 treated by SA.Its tensile strength,Young's modulus,flexural strength,elastic modulus and impact strength of the ternary composite were increased by 124.6%,302.7%,73.86%,58.97% and 27.25% over those of HDPE,respectively.
2008, 25(11): 1301-1305
Abstract:
After properly heat-activated treatment,a functional polymer PSB(polyschiff base) nanomaterial,PSB-1~PSB4,was successfully obtained and used as catalyst in water pollution treatment.The samples were determined by means of DTA-TG,TEM,FT-IR and UV-Vis.Results show that under natural light and air conditions,methylene blue(MB) could be almost fully degraded in the presence of PSB within a few minutes,the mineralizing efficiency reached to 65.7%.Furthermore,the catalyst has superior stability and it can be reused for nine runs.The existence of conjugation structure and polar groups such as C=N,C=O was found to be decisive factors for the catalytic property.
After properly heat-activated treatment,a functional polymer PSB(polyschiff base) nanomaterial,PSB-1~PSB4,was successfully obtained and used as catalyst in water pollution treatment.The samples were determined by means of DTA-TG,TEM,FT-IR and UV-Vis.Results show that under natural light and air conditions,methylene blue(MB) could be almost fully degraded in the presence of PSB within a few minutes,the mineralizing efficiency reached to 65.7%.Furthermore,the catalyst has superior stability and it can be reused for nine runs.The existence of conjugation structure and polar groups such as C=N,C=O was found to be decisive factors for the catalytic property.
2008, 25(11): 1306-1310
Abstract:
Sulfurized rapeseed oil was synthesized via the reaction of refined rapeseed oil and sulfur in the presence of natural mordenite as a catalyst.The chemical structures of the products were analyzed by FTIR.The tribological performance of the sulfurized rapeseed oil was examined on a four-ball tribometer,and the lubrication mechanism was discussed by means of micrographs of wear scars and XPS.It was shown that the unsaturation degree decreased with increasing sulfur content.The reaction yield could exceed 98% in the presence of natural mordenite.The tribological performance of the rapeseed oil was improved with the sulfur content increased from zero to 9.96%.The friction coefficient decreased from 0.085 to 0.025,the wear scar diameter decreased from 0.56 mm to 0.42 mm,the maximum non-seizure load(PB value) increased from 549 N to 745 N,and the welding load(PD value) increased from 1 960 N to 2 254 N.The lubrication mechanism was ascribed to a lubrication film formed by the adsorption of the polar chain molecules and the tribological chemistry reaction of active sulfur element on the friction surface.
Sulfurized rapeseed oil was synthesized via the reaction of refined rapeseed oil and sulfur in the presence of natural mordenite as a catalyst.The chemical structures of the products were analyzed by FTIR.The tribological performance of the sulfurized rapeseed oil was examined on a four-ball tribometer,and the lubrication mechanism was discussed by means of micrographs of wear scars and XPS.It was shown that the unsaturation degree decreased with increasing sulfur content.The reaction yield could exceed 98% in the presence of natural mordenite.The tribological performance of the rapeseed oil was improved with the sulfur content increased from zero to 9.96%.The friction coefficient decreased from 0.085 to 0.025,the wear scar diameter decreased from 0.56 mm to 0.42 mm,the maximum non-seizure load(PB value) increased from 549 N to 745 N,and the welding load(PD value) increased from 1 960 N to 2 254 N.The lubrication mechanism was ascribed to a lubrication film formed by the adsorption of the polar chain molecules and the tribological chemistry reaction of active sulfur element on the friction surface.
2008, 25(11): 1311-1314
Abstract:
A sol-gel process catalyzed by nickel nitrate was used for the preparation of SiC precursor from raw materials of tetraethyl orthosilicate(TEOS) and sucrose.Nano-silicon carbide(nano-SiC) was synthesized from SiC precursor by carbothermal reduction under dynamic vacuum condition at 1 000℃.The surface area of the obtained nano-SiC was 104 m2/g and the particle size was in the range from 40 to 60 nm.Pt/SiC for CO oxidation was then prepared by incipient wetness impregnation of nano-SiC.The result shows that the catalyst exhibits relatively high activity.The addition of Fe results in the improvement of catalytic performance for the oxidation of CO.Compared to Pt/SiC,the lowest temperature for the complete conversion of CO on Pt-Fe/SiC-2(195℃) is lowered by 45℃.
A sol-gel process catalyzed by nickel nitrate was used for the preparation of SiC precursor from raw materials of tetraethyl orthosilicate(TEOS) and sucrose.Nano-silicon carbide(nano-SiC) was synthesized from SiC precursor by carbothermal reduction under dynamic vacuum condition at 1 000℃.The surface area of the obtained nano-SiC was 104 m2/g and the particle size was in the range from 40 to 60 nm.Pt/SiC for CO oxidation was then prepared by incipient wetness impregnation of nano-SiC.The result shows that the catalyst exhibits relatively high activity.The addition of Fe results in the improvement of catalytic performance for the oxidation of CO.Compared to Pt/SiC,the lowest temperature for the complete conversion of CO on Pt-Fe/SiC-2(195℃) is lowered by 45℃.
2008, 25(11): 1315-1319
Abstract:
Nine derivatives of natural lignin diphyllin were synthesized.Five ether derivatives were synthesized via Williamson etherification with the yields of 76%~93%.Four arylacylester derivatives of diphyllin were synthesized in the presence of DCC with the yields of 81%~85%.These compounds were identified by 1H NMR,13C NMR,HRMS and elemental analysis.
Nine derivatives of natural lignin diphyllin were synthesized.Five ether derivatives were synthesized via Williamson etherification with the yields of 76%~93%.Four arylacylester derivatives of diphyllin were synthesized in the presence of DCC with the yields of 81%~85%.These compounds were identified by 1H NMR,13C NMR,HRMS and elemental analysis.
2008, 25(11): 1320-1323
Abstract:
Porous silica surface was treated with hydrobromic acid in excess at a low temperature of-10~0℃,in a solution of silane coupling agent of pH 3.5~4.0 adjusted with acetic acid,and bromine-containing active film/silica composites were prepared.The surface structure was characterized with X-ray photoelectron spectroscopy and scanning electron microscopy.The bromine at the surface of the composite was characterized with infrared spectrum.The bromine contents were measured with fluorescent X-ray spectroscopy after cold water or boiling water treatment,respectively.An active film with stable structure was formed on the surface of the silica composite,onto which bromine was grafted with a mass concentration as high as 0.34%.The bromine content at the surface of the composite was found to decrease after washing with water and hot water was more effective than cold water.In addition,the samples treated by water and then bromine showed higher bromine contents than the ones treated by bromine and then water.After the composites were washed for 30 min by cold water or boiling water,the bromine content of the former decreased to 0.15% and 0.13%,respectively,and the bromine content of the latter decreased to 0.09% and 0.03%,respectively.
Porous silica surface was treated with hydrobromic acid in excess at a low temperature of-10~0℃,in a solution of silane coupling agent of pH 3.5~4.0 adjusted with acetic acid,and bromine-containing active film/silica composites were prepared.The surface structure was characterized with X-ray photoelectron spectroscopy and scanning electron microscopy.The bromine at the surface of the composite was characterized with infrared spectrum.The bromine contents were measured with fluorescent X-ray spectroscopy after cold water or boiling water treatment,respectively.An active film with stable structure was formed on the surface of the silica composite,onto which bromine was grafted with a mass concentration as high as 0.34%.The bromine content at the surface of the composite was found to decrease after washing with water and hot water was more effective than cold water.In addition,the samples treated by water and then bromine showed higher bromine contents than the ones treated by bromine and then water.After the composites were washed for 30 min by cold water or boiling water,the bromine content of the former decreased to 0.15% and 0.13%,respectively,and the bromine content of the latter decreased to 0.09% and 0.03%,respectively.
2008, 25(11): 1324-1329
Abstract:
Pb-Sb alloys were plated from methylsulfonic acid bath.The cyclic voltammetry experiments show that the initial co-deposition potential of the Pb-Sb alloy was about-0.924 V(vs.Hg-Hg2SO4,saturated K2SO4),and the reduction co-deposition was controlled by diffusion.The effect of the cathodic current density on the structure of the Pb-Sb deposit was studied by X-ray diffraction,scanning electron microscopy and energy dispersive X-ray,respectively.As a result,with the increase of the cathodic current density from 5×10-3 to 2.0×10-2 A/cm2,the Pb molar ratio in the deposit increased from 33.6% to 82.4%.Further increasing the cathodic current density reduced the Pb content.The coating was a Pb-Sb solid solution with face centered lattice structure(Fm3m).The electrochemical performance of the Pb-Sb deposit in sulphate acid was analyzed with electrochemical experiments.The results indicate that the Pb-Sb deposit is more suitable for lead-acid battery grid material than lead.
Pb-Sb alloys were plated from methylsulfonic acid bath.The cyclic voltammetry experiments show that the initial co-deposition potential of the Pb-Sb alloy was about-0.924 V(vs.Hg-Hg2SO4,saturated K2SO4),and the reduction co-deposition was controlled by diffusion.The effect of the cathodic current density on the structure of the Pb-Sb deposit was studied by X-ray diffraction,scanning electron microscopy and energy dispersive X-ray,respectively.As a result,with the increase of the cathodic current density from 5×10-3 to 2.0×10-2 A/cm2,the Pb molar ratio in the deposit increased from 33.6% to 82.4%.Further increasing the cathodic current density reduced the Pb content.The coating was a Pb-Sb solid solution with face centered lattice structure(Fm3m).The electrochemical performance of the Pb-Sb deposit in sulphate acid was analyzed with electrochemical experiments.The results indicate that the Pb-Sb deposit is more suitable for lead-acid battery grid material than lead.
2008, 25(11): 1330-1333
Abstract:
Mexiletine hydrochloride was determined by capillary electrophoresis with amperometric detection(CE-AD).The pH,type,concentration of buffer,applied voltage and sample injection time were selected as the investigation variables.Under the optimized conditions:a running buffer composed of 30 mmol/L Na2B4O7 at a pH value of 8.5,separation voltage 15 kV,injection time 10 seconds and detection potential at 0.6 V,a linearity exists between peak height(Y) and mass concentration of Mexiletine hydrochloride(c) in a range of 0.05~50 mg/L,r=0.999 4,and the determination limit is 0.01 mg/L.
Mexiletine hydrochloride was determined by capillary electrophoresis with amperometric detection(CE-AD).The pH,type,concentration of buffer,applied voltage and sample injection time were selected as the investigation variables.Under the optimized conditions:a running buffer composed of 30 mmol/L Na2B4O7 at a pH value of 8.5,separation voltage 15 kV,injection time 10 seconds and detection potential at 0.6 V,a linearity exists between peak height(Y) and mass concentration of Mexiletine hydrochloride(c) in a range of 0.05~50 mg/L,r=0.999 4,and the determination limit is 0.01 mg/L.
2008, 25(11): 1334-1338
Abstract:
Single-phase perovskite oxide Sm1-xSrxCrO3(0 ≤ x ≤ 0.1) was synthesized by Glycine-Nitrate Process(GNP) and characterized by X-ray diffraction(XRD),SEM,DC conductivity and EIS measurement,respectively.Results indicate that Sm1-xSrxCrO3 was p-type semiconductor.The conductivity increased with the increase of Sr doping concentration.Sm1-xSrxCrO3 showed a good chemical stability under both broad oxygen partial pressure and water vapor pressure at high temperatures.Sm0.9Sr0.1CrO3/YSZ(SSCO1/YSZ) composite anodes exhibited good performance for the methane oxidation reaction in CH4 and O2 mixed atmospheres.The best electrode performance was achieved for the composite with a YSZ content ω(YSZ) of 23%,which gave the lowest polarization resistance of 3.24 Ω·cm2 at 800℃ in a mixed atmosphere of CH4 and O2.
Single-phase perovskite oxide Sm1-xSrxCrO3(0 ≤ x ≤ 0.1) was synthesized by Glycine-Nitrate Process(GNP) and characterized by X-ray diffraction(XRD),SEM,DC conductivity and EIS measurement,respectively.Results indicate that Sm1-xSrxCrO3 was p-type semiconductor.The conductivity increased with the increase of Sr doping concentration.Sm1-xSrxCrO3 showed a good chemical stability under both broad oxygen partial pressure and water vapor pressure at high temperatures.Sm0.9Sr0.1CrO3/YSZ(SSCO1/YSZ) composite anodes exhibited good performance for the methane oxidation reaction in CH4 and O2 mixed atmospheres.The best electrode performance was achieved for the composite with a YSZ content ω(YSZ) of 23%,which gave the lowest polarization resistance of 3.24 Ω·cm2 at 800℃ in a mixed atmosphere of CH4 and O2.
2008, 25(11): 1339-1344
Abstract:
A double self-crosslinked polyurethane-acrylate(PUA) hybrid emulsion crosslinked not only by ketone and hydrazide groups but also by epoxy and carboxyl groups was synthesized by emulsion polymerization in situ with toluene diisocyanate(TDI-80),polyether binary alcohol(Diol-1000),butanediol(BDO),dimethylol propionic acid(DMPA),methyl methacrylate(MMA),Glycidyl methacrylate(GMA),adipic dihydrazide(ADH) and diacetone acrylamide(DAAM) as reactants.The influence of the ratio of hydrazide group to isocyanate group,the ratio of ketone group to hydrazide group to the dosage of epoxy group on the preparation and performance of the emulsion and its film was studied.When the mass fractions of ADH,DAAM,COOH in DMPA and GMA in PUA were respectively 4.1%,2.2%,1.6%,and 4.0%,the emulsion and film both exhibited good properties.The pencil hardness of the double self-crosslinked PUA hybrid emulsion was 3H.The results obtained by particle size analyzer show that the average particle size of the PUA was about 100 nm and the particle size distribution was uniform.
A double self-crosslinked polyurethane-acrylate(PUA) hybrid emulsion crosslinked not only by ketone and hydrazide groups but also by epoxy and carboxyl groups was synthesized by emulsion polymerization in situ with toluene diisocyanate(TDI-80),polyether binary alcohol(Diol-1000),butanediol(BDO),dimethylol propionic acid(DMPA),methyl methacrylate(MMA),Glycidyl methacrylate(GMA),adipic dihydrazide(ADH) and diacetone acrylamide(DAAM) as reactants.The influence of the ratio of hydrazide group to isocyanate group,the ratio of ketone group to hydrazide group to the dosage of epoxy group on the preparation and performance of the emulsion and its film was studied.When the mass fractions of ADH,DAAM,COOH in DMPA and GMA in PUA were respectively 4.1%,2.2%,1.6%,and 4.0%,the emulsion and film both exhibited good properties.The pencil hardness of the double self-crosslinked PUA hybrid emulsion was 3H.The results obtained by particle size analyzer show that the average particle size of the PUA was about 100 nm and the particle size distribution was uniform.
2008, 25(11): 1345-1350
Abstract:
A series of cleavable aryl sulfonate anionic surfactants with different carbon chains were synthesized from cyanuric chloride,aliphatic amine,and H acid mono sodium salt.Their structures were identified by 1H NMR,IR,and elemental analysis.Their critical micell concentrations(CMC) in aqueous solutions at 25℃ were determined by steady-state fluorescence probe method and surface-tension method,respectively.With increased length of the carbon chain,the values of their CMC and surface tensions under CMC(γCMC) first decreased and reached minima(1.5×10-5 mol/L and 28.29 mN/m respectively) when the carbon number was 10.Then the CMC and γCMC increased when the carbon number was 12.Compared with sodium dodecyl benzene sulfonate(SDBS),such kinds of surfactants have much lower surface adsorption amounts and greater molecular areas on the aqueous surface.Stability test results demonstrate that these surfactants are cleavable.
A series of cleavable aryl sulfonate anionic surfactants with different carbon chains were synthesized from cyanuric chloride,aliphatic amine,and H acid mono sodium salt.Their structures were identified by 1H NMR,IR,and elemental analysis.Their critical micell concentrations(CMC) in aqueous solutions at 25℃ were determined by steady-state fluorescence probe method and surface-tension method,respectively.With increased length of the carbon chain,the values of their CMC and surface tensions under CMC(γCMC) first decreased and reached minima(1.5×10-5 mol/L and 28.29 mN/m respectively) when the carbon number was 10.Then the CMC and γCMC increased when the carbon number was 12.Compared with sodium dodecyl benzene sulfonate(SDBS),such kinds of surfactants have much lower surface adsorption amounts and greater molecular areas on the aqueous surface.Stability test results demonstrate that these surfactants are cleavable.
2008, 25(11): 1351-1355
Abstract:
With a tricyclic antidepressant amitriptyline hydrochloride(AH) as the model drug,Alginate as the inside layer,and chitosan as the outside layer,amitriptyline hydrochloride-Alginate-chitosan microspheres were prepared by emulsion cross-linking technique with ethylene glycol diglycidyl ether(EGDE) as the cross-linking agent.The physicochemical properties and the drug-release performance of the microspheres were investigated.The microspheres had a spherical shape and were white in color,and the averaged diameter was about 18.70 μm.The drug content was 9.5%(mass fraction) and the drug loading efficiency could reach 53.25%.XRD analysis indicated that the AH in the microspheres were amorphous.The microspheres had a satisfactory performance of slowly releasing the AH.With the increase of the concentration of Alginate,the releasing rate of amitriptyline hydrochloride decreased;with the increase of pH,the releasing rate of amitriptyline hydrochloride increased;with the increase of the ratio of amitriptyline hydrochloride to Alginate by weight,the releasing rate of AH increased.The release rate of AH in acidic buffer was faster than that of AH in alkaline buffer.
With a tricyclic antidepressant amitriptyline hydrochloride(AH) as the model drug,Alginate as the inside layer,and chitosan as the outside layer,amitriptyline hydrochloride-Alginate-chitosan microspheres were prepared by emulsion cross-linking technique with ethylene glycol diglycidyl ether(EGDE) as the cross-linking agent.The physicochemical properties and the drug-release performance of the microspheres were investigated.The microspheres had a spherical shape and were white in color,and the averaged diameter was about 18.70 μm.The drug content was 9.5%(mass fraction) and the drug loading efficiency could reach 53.25%.XRD analysis indicated that the AH in the microspheres were amorphous.The microspheres had a satisfactory performance of slowly releasing the AH.With the increase of the concentration of Alginate,the releasing rate of amitriptyline hydrochloride decreased;with the increase of pH,the releasing rate of amitriptyline hydrochloride increased;with the increase of the ratio of amitriptyline hydrochloride to Alginate by weight,the releasing rate of AH increased.The release rate of AH in acidic buffer was faster than that of AH in alkaline buffer.
2008, 25(11): 1356-1360
Abstract:
Fluorodenitration is one of the efficient methods for preparation of fluoronitrobenzenes with the advantages of raw material availability,simple process,and high product yields.In this paper,fluorodenitration of dinitrobenzenes was studied.The effects of fluorinating agent,solvent,reaction time,and catalyst,etc on the fluorodenitration were studied.The results show the optimum reaction conditions were 2.1 g(12.5 mmol) of dinitrobenzene,2.9 g(50 mmol) of SD-KF,0.53 g(1.25 mmol) of Ph4PBr,0.13 mL(2.5 mmol) of tetraethylene glycol dimethyl ether in the presence of 1.8 mL(12.5 mmol) of PDC as a trapping agent of NO2-,and the mixture was stirred at 210℃ for 1~5 h in nitrobenzene,resulting in 94.1%~98.5% conversions and 81.6%~87.4% yields.
Fluorodenitration is one of the efficient methods for preparation of fluoronitrobenzenes with the advantages of raw material availability,simple process,and high product yields.In this paper,fluorodenitration of dinitrobenzenes was studied.The effects of fluorinating agent,solvent,reaction time,and catalyst,etc on the fluorodenitration were studied.The results show the optimum reaction conditions were 2.1 g(12.5 mmol) of dinitrobenzene,2.9 g(50 mmol) of SD-KF,0.53 g(1.25 mmol) of Ph4PBr,0.13 mL(2.5 mmol) of tetraethylene glycol dimethyl ether in the presence of 1.8 mL(12.5 mmol) of PDC as a trapping agent of NO2-,and the mixture was stirred at 210℃ for 1~5 h in nitrobenzene,resulting in 94.1%~98.5% conversions and 81.6%~87.4% yields.
2008, 25(11): 1361-1365
Abstract:
CNTs were first oxidized in a mixture of c(K2Cr2O7)=0.25 mol/L and an acid with c(H+)=1 mol/L to obtain CNTs with hydroxyl groups on their surfaces,then the oxidized CNTs were grafted with hyperbranched poly(amin-ester) through one-step polycondensation between A2B monomer and active hydroxyl on CNTs surface in the presence of catalyst.The reaction conditions were studied and optimized with respect to the amount of HPAE coupled with CNTs.Under the conditions:n(CNTs-OH):n(A2B monomer)=1:6,reaction time=10 h,reaction temperature 120℃,the amount of HPAE coupled with CNTs reached to 0.255.From the results of FTIR,XPS and TEM,it can be found that hyperbranched poly(amin-ester) is successfully grafted onto the surface of CNTs.The results indicate that CNTs grafted with hyperbranched poly(amin-ester) exhibit better dispersion in acetone,ethanol or water than unmodified CNTs.
CNTs were first oxidized in a mixture of c(K2Cr2O7)=0.25 mol/L and an acid with c(H+)=1 mol/L to obtain CNTs with hydroxyl groups on their surfaces,then the oxidized CNTs were grafted with hyperbranched poly(amin-ester) through one-step polycondensation between A2B monomer and active hydroxyl on CNTs surface in the presence of catalyst.The reaction conditions were studied and optimized with respect to the amount of HPAE coupled with CNTs.Under the conditions:n(CNTs-OH):n(A2B monomer)=1:6,reaction time=10 h,reaction temperature 120℃,the amount of HPAE coupled with CNTs reached to 0.255.From the results of FTIR,XPS and TEM,it can be found that hyperbranched poly(amin-ester) is successfully grafted onto the surface of CNTs.The results indicate that CNTs grafted with hyperbranched poly(amin-ester) exhibit better dispersion in acetone,ethanol or water than unmodified CNTs.
2008, 25(11): 1366-1368
Abstract:
An isocratic chiral HPLC method was developed for the separation of Norepinephrine Bitartrate enantiomers.The enantioseperation was carried out on a Chiralpak AD-H column with V(n-hexane):V(ethanol):V(ethanolamine)=80:20:0.2 as the mobile phase at UV 280 nm.The method is precise,linear,sensitive and accurate for quantification or ee(%) determination.The relationship between specific rotation and enantiomeric excess purity was studied for Norepinephrine Bitartrate products.
An isocratic chiral HPLC method was developed for the separation of Norepinephrine Bitartrate enantiomers.The enantioseperation was carried out on a Chiralpak AD-H column with V(n-hexane):V(ethanol):V(ethanolamine)=80:20:0.2 as the mobile phase at UV 280 nm.The method is precise,linear,sensitive and accurate for quantification or ee(%) determination.The relationship between specific rotation and enantiomeric excess purity was studied for Norepinephrine Bitartrate products.
2008, 25(11): 1369-1371
Abstract:
A new method to synthesize chlorophenyl isocyanates from corredponding chloroanilines and triphosgene was studied.The optimal reaction conditions were found via investigating the effects of solvent,reaction time and mole ratio of reactants on the yield.The results show that the optimal sovent is 1,2-dichlo-roethane,the optimal reaction time to prepare o-chlorophenyl isocyanates,m-chlorophenyl isocyanates and p-chlorophenyl isocyanates is respectively 5 h,4.5 h and 4.5 h,the optimal mole ratio of corredponding chloroanilines and triphosgene is respectively 2.2:1,2:1 and 2:1.Under those conditions,the highest yields of o-chlorophenyl isocyanates m-chlorophenyl isocyanates and p-chlorophenyl isocyanates are respectively 84.7%,86.2% and 89.0%,and the purities of the products are respectively 96.18%,97.83% and 99.55%.
A new method to synthesize chlorophenyl isocyanates from corredponding chloroanilines and triphosgene was studied.The optimal reaction conditions were found via investigating the effects of solvent,reaction time and mole ratio of reactants on the yield.The results show that the optimal sovent is 1,2-dichlo-roethane,the optimal reaction time to prepare o-chlorophenyl isocyanates,m-chlorophenyl isocyanates and p-chlorophenyl isocyanates is respectively 5 h,4.5 h and 4.5 h,the optimal mole ratio of corredponding chloroanilines and triphosgene is respectively 2.2:1,2:1 and 2:1.Under those conditions,the highest yields of o-chlorophenyl isocyanates m-chlorophenyl isocyanates and p-chlorophenyl isocyanates are respectively 84.7%,86.2% and 89.0%,and the purities of the products are respectively 96.18%,97.83% and 99.55%.
2008, 25(11): 1372-1374
Abstract:
The oxidation of NH3 in DMF with LiClO4 as the electrolyte was investigated.It was found for the first time that when NH3 is oxidized in this electrolyte,DMF is also oxidized in the similar potential range.This would interfere with the detection of NH3.However,if an ionic liquid,BF4,is added into DMF,the oxidation of DMF would be inhibited and the oxidation peak of NH3 would shift negatively from 1.15 V to 0.90 V,suppressing the interference by DMF to the detection of NH3.This result suggests a new idea for developing a new electrolyte for potential-fixed electrochemical NH3 sensors.
The oxidation of NH3 in DMF with LiClO4 as the electrolyte was investigated.It was found for the first time that when NH3 is oxidized in this electrolyte,DMF is also oxidized in the similar potential range.This would interfere with the detection of NH3.However,if an ionic liquid,BF4,is added into DMF,the oxidation of DMF would be inhibited and the oxidation peak of NH3 would shift negatively from 1.15 V to 0.90 V,suppressing the interference by DMF to the detection of NH3.This result suggests a new idea for developing a new electrolyte for potential-fixed electrochemical NH3 sensors.
2008, 25(11): 1375-1377
Abstract:
A novel efficient method for preparing L-and D-fork glycerinol is described.Highly enantioenriched(S)-epichlorohydrin and(R)-3-chloro-1,2-propanediol were prepared from the reaction of dynamic hydrolysis resolution of racemic epichlorohydrin by chiral Salen-CoⅢ complex.(S)-epichlorohydrin was used to afford L-fork glycerinol by hydrolysis,condensation,displacement,and alcoholysis.The overall yield was 59.4%.D-fork glycerinol was prepared from(R)-3-chloro-1,2-propanediol,and the overall yield was 62.5%.The chemical structures of the target compounds were confirmed by IR,1H NMR and MS.
A novel efficient method for preparing L-and D-fork glycerinol is described.Highly enantioenriched(S)-epichlorohydrin and(R)-3-chloro-1,2-propanediol were prepared from the reaction of dynamic hydrolysis resolution of racemic epichlorohydrin by chiral Salen-CoⅢ complex.(S)-epichlorohydrin was used to afford L-fork glycerinol by hydrolysis,condensation,displacement,and alcoholysis.The overall yield was 59.4%.D-fork glycerinol was prepared from(R)-3-chloro-1,2-propanediol,and the overall yield was 62.5%.The chemical structures of the target compounds were confirmed by IR,1H NMR and MS.
2008, 25(11): 1378-1380
Abstract:
A high performance liquid chromatographic method was developed for determination of dibenz-1,4-oxazepine and its impurities.The stability of dibenz-1,4-oxazepine was investigated utilizing a Luna C18 column with a mobile phase consisted of the mixture of acetonitrile,methanol and acetic acid solution at a concentration of 0.2%(36:13:51,volume ratio).Content of the impurity product present in the sample was found to increase from below 0.1% to 0.67%,after accelerated testing,and it was identified as N-formyl-phenoxazine by high performance liquid chromatography coupled with electrospray ion-trap mass spectrometry.
A high performance liquid chromatographic method was developed for determination of dibenz-1,4-oxazepine and its impurities.The stability of dibenz-1,4-oxazepine was investigated utilizing a Luna C18 column with a mobile phase consisted of the mixture of acetonitrile,methanol and acetic acid solution at a concentration of 0.2%(36:13:51,volume ratio).Content of the impurity product present in the sample was found to increase from below 0.1% to 0.67%,after accelerated testing,and it was identified as N-formyl-phenoxazine by high performance liquid chromatography coupled with electrospray ion-trap mass spectrometry.
