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2007 Volume 24 Issue 2
2007, 24(2): 117-123
Abstract:
The recent developments concerning the synthesis,properties and applications of functionalized ionic liquids in organic synthesis are reviewed.Various strategies are presented,including functionalization of cations or anions.Particular attention is given to the synthesis and application of chiral ionic liquids,acid ionic liquids and ILs-supported regents or catalysts in synthetical chemistry.
The recent developments concerning the synthesis,properties and applications of functionalized ionic liquids in organic synthesis are reviewed.Various strategies are presented,including functionalization of cations or anions.Particular attention is given to the synthesis and application of chiral ionic liquids,acid ionic liquids and ILs-supported regents or catalysts in synthetical chemistry.
2007, 24(2): 124-127
Abstract:
A series of segmented poly(L-lactide)-polyurethanes(PLA-PU) were synthesized via a two-step method,with oligo-poly(L-lactide)(PLA) as the soft segments and the reaction product of 2,4-toluene diiso-cyanate(TDI) and ethylene glycol(EG) as the hard segments.The molecular mass(Mn) of the PLA was 1500~9500,and the molar ratio of PLA/TDI/EG was from 1:2:1 to 1:7:6.The degree of phase separation in the PLA-PUs was examined as a function of their composition and thermal history with differential scanning calorimetry and wide-angle X-ray diffraction(WAXD).The results show that the thermal history has an impor-tant impact on the degree of phase separation in PLA-PUs,and the molecular mass of the PLA segments and the length of the TDI-EG segments have evident influence on the rate and perfection of the phase separation.
A series of segmented poly(L-lactide)-polyurethanes(PLA-PU) were synthesized via a two-step method,with oligo-poly(L-lactide)(PLA) as the soft segments and the reaction product of 2,4-toluene diiso-cyanate(TDI) and ethylene glycol(EG) as the hard segments.The molecular mass(Mn) of the PLA was 1500~9500,and the molar ratio of PLA/TDI/EG was from 1:2:1 to 1:7:6.The degree of phase separation in the PLA-PUs was examined as a function of their composition and thermal history with differential scanning calorimetry and wide-angle X-ray diffraction(WAXD).The results show that the thermal history has an impor-tant impact on the degree of phase separation in PLA-PUs,and the molecular mass of the PLA segments and the length of the TDI-EG segments have evident influence on the rate and perfection of the phase separation.
2007, 24(2): 128-133
Abstract:
The adsorption of bovine serum albumin(BSA) onto nanocrystalline hydroxyapatite and TiO2 was studied by electrochemical quartz crystal impedance and FTIR-ATR spectroscopy.The response parameters of piezoelectric quartz crystal(PQC) resonance,frequency and the changes in the double electric layer capaci-tance were obtained during BSA adsorption.The adsorption kinetics was analyzed with a scheme of two consec-utive reactions occurring at the interface.The adsorption rate of BSA on TiO2 surface was lower than that on HAP surface.The saturated surface coverages of BSA were respectively 1.09×10-6 and 1.12×10-6 g/cm2 on HAP and TiO2 calculated via the Sauerbrey's equation.FTIR-ATR spectroscopy was used to study the adsorption kinetics and the change of the BSA second order structure.The experimental results show that the structure of the biomaterial affects both the adsorption kinetics and the second order structure of the BSA and the effect of HAP on the BSA adsorption is more notably.
The adsorption of bovine serum albumin(BSA) onto nanocrystalline hydroxyapatite and TiO2 was studied by electrochemical quartz crystal impedance and FTIR-ATR spectroscopy.The response parameters of piezoelectric quartz crystal(PQC) resonance,frequency and the changes in the double electric layer capaci-tance were obtained during BSA adsorption.The adsorption kinetics was analyzed with a scheme of two consec-utive reactions occurring at the interface.The adsorption rate of BSA on TiO2 surface was lower than that on HAP surface.The saturated surface coverages of BSA were respectively 1.09×10-6 and 1.12×10-6 g/cm2 on HAP and TiO2 calculated via the Sauerbrey's equation.FTIR-ATR spectroscopy was used to study the adsorption kinetics and the change of the BSA second order structure.The experimental results show that the structure of the biomaterial affects both the adsorption kinetics and the second order structure of the BSA and the effect of HAP on the BSA adsorption is more notably.
2007, 24(2): 134-138
Abstract:
Photoresists made of hyperbranched polyesters modified with epoxy resin were prepared and used as glass etching mask.Photo-reactivity of the modified hyperbranched polyesters,resistance of the mask to the etching agents composed of HCl,HNO3 and HF,and the glass etching were studied.Adhesion of the mask film to glass is improved by the hyperbranched polyesters modified with epoxy resin.Sensitivity(T0,gel) and contrast(γgel) of the photoresists are 2.7 s and 2.8,respectively.The wet etching agents made of HF,HCl and HNO3 exhibit high etching rates(≥35μm/min).Photoresists made of the modified photo reactive hyper-branched polyesters were photo patterned and were used as the mask for glass etching.Clear etching patterns on the glass plates with line width of 50μm were prepared.Etching depth over 38μm was also realized.
Photoresists made of hyperbranched polyesters modified with epoxy resin were prepared and used as glass etching mask.Photo-reactivity of the modified hyperbranched polyesters,resistance of the mask to the etching agents composed of HCl,HNO3 and HF,and the glass etching were studied.Adhesion of the mask film to glass is improved by the hyperbranched polyesters modified with epoxy resin.Sensitivity(T0,gel) and contrast(γgel) of the photoresists are 2.7 s and 2.8,respectively.The wet etching agents made of HF,HCl and HNO3 exhibit high etching rates(≥35μm/min).Photoresists made of the modified photo reactive hyper-branched polyesters were photo patterned and were used as the mask for glass etching.Clear etching patterns on the glass plates with line width of 50μm were prepared.Etching depth over 38μm was also realized.
2007, 24(2): 139-143
Abstract:
The SnⅡ-substituted Keggin-type tungstophosphate and tungstosilicate were synthesized.The samples were characterized by means of IR,UV-Vis spectroscopy and 31P NMR measurement.It is shown that the synthesized compounds are pure SnⅡ-substituted polyoxometalates,and no SnⅣ-substituted species are included.No Sn2+ enters the central position of vacant octahedron in the lacunary structure,thus the symme-try of the polyoxoanion lies between the saturated and the lacunary structures.Furthermore,the photocatalytic activities of these polyoxometalates for the degradation of aqueous dye were also investigated.It is demons-trated that the SnⅡ-substituted compounds are of high photocatalytic activities,which are higher than those of often employed PW12 and SiW12 compounds.The SnⅡ-substituted tungstosilicate even showed a high photo-catalytic activity for methyl orange and methylene blue under the scattered sunlight.The degradation percen-tages of these dyes are over 90% after a reaction progress for 7 h.Study on photocatalytic mechanism shows that no high energy for O→W charge transfer is needed for SnⅡ-substituted polyoxometalates.The radiation of lower energy can excite the electrons at HOMO level and ignite the photocatalytic reaction.Therefore SnⅡ-substituted polyoxometalates can greatly increase the utilization of light energy.
The SnⅡ-substituted Keggin-type tungstophosphate and tungstosilicate were synthesized.The samples were characterized by means of IR,UV-Vis spectroscopy and 31P NMR measurement.It is shown that the synthesized compounds are pure SnⅡ-substituted polyoxometalates,and no SnⅣ-substituted species are included.No Sn2+ enters the central position of vacant octahedron in the lacunary structure,thus the symme-try of the polyoxoanion lies between the saturated and the lacunary structures.Furthermore,the photocatalytic activities of these polyoxometalates for the degradation of aqueous dye were also investigated.It is demons-trated that the SnⅡ-substituted compounds are of high photocatalytic activities,which are higher than those of often employed PW12 and SiW12 compounds.The SnⅡ-substituted tungstosilicate even showed a high photo-catalytic activity for methyl orange and methylene blue under the scattered sunlight.The degradation percen-tages of these dyes are over 90% after a reaction progress for 7 h.Study on photocatalytic mechanism shows that no high energy for O→W charge transfer is needed for SnⅡ-substituted polyoxometalates.The radiation of lower energy can excite the electrons at HOMO level and ignite the photocatalytic reaction.Therefore SnⅡ-substituted polyoxometalates can greatly increase the utilization of light energy.
2007, 24(2): 144-147
Abstract:
A novel long path absorbance spectroscopy(LPAS) for the determination of trace formaldehyde was established.Trace formaldehyde was determined by the combination of liquid core waveguide(LCW,9 cm) and light intensity difference technique(△I),with an ultra bright red light emitting diode(LED) working as spectroscopic source and a photodiode as photodetector.It was analyzed following Chinese National Standard of determination for formaldehyde in public air,GB/Y18204.26-2000.The linear range and detection limit of the proposed method were 1.0×10-11~1.0×10-9g/mL,7×1012g/mL,respectively.The relative standard derivation(RSD) for 1×1010g/mL formaldehyde was less than 1.0%(n=11).The results shown that both the low limit of linear range and the detection limit of this method were over 1000-fold lower than that of usual UV-Vis method.
A novel long path absorbance spectroscopy(LPAS) for the determination of trace formaldehyde was established.Trace formaldehyde was determined by the combination of liquid core waveguide(LCW,9 cm) and light intensity difference technique(△I),with an ultra bright red light emitting diode(LED) working as spectroscopic source and a photodiode as photodetector.It was analyzed following Chinese National Standard of determination for formaldehyde in public air,GB/Y18204.26-2000.The linear range and detection limit of the proposed method were 1.0×10-11~1.0×10-9g/mL,7×1012g/mL,respectively.The relative standard derivation(RSD) for 1×1010g/mL formaldehyde was less than 1.0%(n=11).The results shown that both the low limit of linear range and the detection limit of this method were over 1000-fold lower than that of usual UV-Vis method.
2007, 24(2): 148-151
Abstract:
γ-Fe2O3 nanopowders were synthesized from the two microemulsion solutions,such as NaOH/DBS/C6H5CH3/H2O and NaOH/CTAB/CHCl3/CH3CH2CH2OH/H2O,and their gas sensing properties were studied.The products were characterized by means of FT-IR,XRD and TEM.The results indicate that spheri-cal γ-Fe2O3 nanoparticles with a particle size of about 4~5 nm can be obtained from the two microemulsion solutions,when DBS and CTAB were used as surfactant and the ratios of W/O were 10.77 and 10.56, respectively.The small particle size can be attributed to the remanant surfactants adsorbed on γ-Fe2O3 nano-particles which prevent the aggregation of γ-Fe2O3 nanoparticles.The sensors,made from γ-Fe2O3 nanopow-ders obtained from the two microemulsion solutions,have high sensitivities of 12.5 for DBS and 23.8 for CTAB to 0.1% ethanol,as well as show short response-recovery time to 0.1% ethanol,that is,20 and 30 s for DBS and 15 and 47 s for CTAB,respectively.Both of them can meet the requirements of practical applications and are promising ethanol sensors due to their sensitivities and good linear relations to the concentration.
γ-Fe2O3 nanopowders were synthesized from the two microemulsion solutions,such as NaOH/DBS/C6H5CH3/H2O and NaOH/CTAB/CHCl3/CH3CH2CH2OH/H2O,and their gas sensing properties were studied.The products were characterized by means of FT-IR,XRD and TEM.The results indicate that spheri-cal γ-Fe2O3 nanoparticles with a particle size of about 4~5 nm can be obtained from the two microemulsion solutions,when DBS and CTAB were used as surfactant and the ratios of W/O were 10.77 and 10.56, respectively.The small particle size can be attributed to the remanant surfactants adsorbed on γ-Fe2O3 nano-particles which prevent the aggregation of γ-Fe2O3 nanoparticles.The sensors,made from γ-Fe2O3 nanopow-ders obtained from the two microemulsion solutions,have high sensitivities of 12.5 for DBS and 23.8 for CTAB to 0.1% ethanol,as well as show short response-recovery time to 0.1% ethanol,that is,20 and 30 s for DBS and 15 and 47 s for CTAB,respectively.Both of them can meet the requirements of practical applications and are promising ethanol sensors due to their sensitivities and good linear relations to the concentration.
2007, 24(2): 152-156
Abstract:
Eleven ethyl α-[4-(substituedbenzylidene) iminophenoxy]propionates were synthesized through coupling of aromatic aldehydes with ethyl α-(4-aminophenoxyl) propionate.All compounds were characterized by means of 1H NMR,UV,IR and elemental analysis.The effects of substituents of aromatic aldehyde on reaction yields were studied.The results showed that the coupling reaction using 4-nitro-benzaldehyde with electron-withdrawing subtituents gave the highest yield in 93%,while the lowest reaction yield of 54% was obtained using 4-methylbenzaldehye,which has electron-donating substituents.The preliminary biological tests show that most of the compounds possess plant growth-regulating activities at a low concentration(10 ppm). Among those compounds,6b and 6f show the root growth-regulating activities of 52% and 55% for Cucumis Sativa L.,respectively;while compound 6j gives a inhibitory activity of 75% for root of Cucumis Sativa L.. Compound 6b also gives a cell-growing activity of 51% for Triticum aestivum L.and compound 6h gives a stalk growth-regulating activity of 53% for Cucumis Sativa L.
Eleven ethyl α-[4-(substituedbenzylidene) iminophenoxy]propionates were synthesized through coupling of aromatic aldehydes with ethyl α-(4-aminophenoxyl) propionate.All compounds were characterized by means of 1H NMR,UV,IR and elemental analysis.The effects of substituents of aromatic aldehyde on reaction yields were studied.The results showed that the coupling reaction using 4-nitro-benzaldehyde with electron-withdrawing subtituents gave the highest yield in 93%,while the lowest reaction yield of 54% was obtained using 4-methylbenzaldehye,which has electron-donating substituents.The preliminary biological tests show that most of the compounds possess plant growth-regulating activities at a low concentration(10 ppm). Among those compounds,6b and 6f show the root growth-regulating activities of 52% and 55% for Cucumis Sativa L.,respectively;while compound 6j gives a inhibitory activity of 75% for root of Cucumis Sativa L.. Compound 6b also gives a cell-growing activity of 51% for Triticum aestivum L.and compound 6h gives a stalk growth-regulating activity of 53% for Cucumis Sativa L.
2007, 24(2): 157-161
Abstract:
Pyrrolidine ring-fused fullerene derivative(C60Pyr) was prepared by photolysis via the reaction of C60 with CH3NHCH2COOMe in 67% yield(based on consumed C60).The product(PyrC60)-Pd(dppe) was obtained by the method of ligand substitution via the reaction of C60Pyr with Pd(dppe)2 in nitrogen atmosphere at room temperature in 51% yield(relative to C60Pyr).The products were characterized by means of elemental analysis,IR,UV-Vis,X-ray photoelectron spectroscopy and 31P NMR.The photovohaic effect(PVE) of the compound on GaAs electrode in electrochemical photovohaic cell were measured.Influences of various redox couples and the thickness of the complex film were observed.The results show that the values of △V and △I for (PyrC60)-Pd(dppe)-GaAs electrode are much greater than those for pure GaAs electrode.So that the photo-electric properities for the compound are excellent,especially in the O2/H2O redox couple,the greatest value of photovoltaic potential was 230 mV,and the greatest value of photovoltaic current was 8.7μA.The results showed that (PyrC60)-Pd(dppe)/GaAs electrode at 0.5~1μm for thinckness of(PyrC60)-Pd(dppe) film was the best.
Pyrrolidine ring-fused fullerene derivative(C60Pyr) was prepared by photolysis via the reaction of C60 with CH3NHCH2COOMe in 67% yield(based on consumed C60).The product(PyrC60)-Pd(dppe) was obtained by the method of ligand substitution via the reaction of C60Pyr with Pd(dppe)2 in nitrogen atmosphere at room temperature in 51% yield(relative to C60Pyr).The products were characterized by means of elemental analysis,IR,UV-Vis,X-ray photoelectron spectroscopy and 31P NMR.The photovohaic effect(PVE) of the compound on GaAs electrode in electrochemical photovohaic cell were measured.Influences of various redox couples and the thickness of the complex film were observed.The results show that the values of △V and △I for (PyrC60)-Pd(dppe)-GaAs electrode are much greater than those for pure GaAs electrode.So that the photo-electric properities for the compound are excellent,especially in the O2/H2O redox couple,the greatest value of photovoltaic potential was 230 mV,and the greatest value of photovoltaic current was 8.7μA.The results showed that (PyrC60)-Pd(dppe)/GaAs electrode at 0.5~1μm for thinckness of(PyrC60)-Pd(dppe) film was the best.
2007, 24(2): 162-167
Abstract:
Based on the structural feature of nonclassical antifolates,a series of 4(3H)-quinazolinone deriva-tives bearing aromatic amine side chains have been designed by incorporating trimethoxyphenyl,an antitumor pharmacophore,with 4(3H)-quinazolinone.N-alkylation of 3,4,5-trimethoxyphenylamine with appropriate a-mount of alkyl halides afforded 4 kinds of N-substituted 3,4,5-trimethoxyphenylamines in 30.3%~60.6% yields.The target compounds 8a~8m were obtained through the reactions of 6-bromo-2-methyl-4(3H)-quin-azolinone with 3,4,5-trimethoxyphenylamine,N-substituted 3,4,5-trimethoxyphenylamines or other aryl-amines at room temperature in 30.8%~71.9% yields,and their structures were confirmed by means of ESI-MS,1H NMR,elemental analysis or HRMS.The in vitro cytotoxicities against A-549(human non-small cell lung cancer),HCT-8(human colon cancer) and Bel-7402(human liver cancer) cell lines of the synthesized compounds 8a~8m were tested with colorimetric MTT assay,and the results indicated that the percent growth inhibition against A-549,HCT-8 and Bel-7402 cell lines at 5×10-6g/mL concentration of the compounds 8a~8m were all lower than 25%.
Based on the structural feature of nonclassical antifolates,a series of 4(3H)-quinazolinone deriva-tives bearing aromatic amine side chains have been designed by incorporating trimethoxyphenyl,an antitumor pharmacophore,with 4(3H)-quinazolinone.N-alkylation of 3,4,5-trimethoxyphenylamine with appropriate a-mount of alkyl halides afforded 4 kinds of N-substituted 3,4,5-trimethoxyphenylamines in 30.3%~60.6% yields.The target compounds 8a~8m were obtained through the reactions of 6-bromo-2-methyl-4(3H)-quin-azolinone with 3,4,5-trimethoxyphenylamine,N-substituted 3,4,5-trimethoxyphenylamines or other aryl-amines at room temperature in 30.8%~71.9% yields,and their structures were confirmed by means of ESI-MS,1H NMR,elemental analysis or HRMS.The in vitro cytotoxicities against A-549(human non-small cell lung cancer),HCT-8(human colon cancer) and Bel-7402(human liver cancer) cell lines of the synthesized compounds 8a~8m were tested with colorimetric MTT assay,and the results indicated that the percent growth inhibition against A-549,HCT-8 and Bel-7402 cell lines at 5×10-6g/mL concentration of the compounds 8a~8m were all lower than 25%.
2007, 24(2): 168-172
Abstract:
Four amphiphilic copolymers of 3-chloro-2-hydroxy-1-propanesulfonate sodium(NaCHPS) and 1-chloro-3-butoxy-2-propanol(CBP) were prepared via base-catalyzed polycondensation.The copolymers were characterized by means of FT-IR,1H and 13C NMR analysis.Vapor Pressure Osmometry(VPO) indicated the total number average molecular weights were in the range of 900~1600.The dynamic surface tension(DST) of sulfonated polyether aqueous solution with different mass concentrations and structures was measured via the plate method.The results show that when the mass concentration increases from 56.4 mg/L to 3 611 mg/L, the value of R1/2 increases from 11.04 mN/(m·min) to 7 662.5 mN/(m·min).Dynamic surface activity of sulfonated polyether increases with increasing sulfonated polyether concentration and 1-chloro-3-butoxy-2-propanol(CBP) unit.
Four amphiphilic copolymers of 3-chloro-2-hydroxy-1-propanesulfonate sodium(NaCHPS) and 1-chloro-3-butoxy-2-propanol(CBP) were prepared via base-catalyzed polycondensation.The copolymers were characterized by means of FT-IR,1H and 13C NMR analysis.Vapor Pressure Osmometry(VPO) indicated the total number average molecular weights were in the range of 900~1600.The dynamic surface tension(DST) of sulfonated polyether aqueous solution with different mass concentrations and structures was measured via the plate method.The results show that when the mass concentration increases from 56.4 mg/L to 3 611 mg/L, the value of R1/2 increases from 11.04 mN/(m·min) to 7 662.5 mN/(m·min).Dynamic surface activity of sulfonated polyether increases with increasing sulfonated polyether concentration and 1-chloro-3-butoxy-2-propanol(CBP) unit.
2007, 24(2): 173-177
Abstract:
High reactive penta-coordinated organic silicon was prepared by the reaction of silica with ethylene glycol and potassium hydroxide.Double bond tetra-coordinated silicon was produced by the reaction of this penta-coordinated silicon with 4-vinylbenzyl chloride;then branch-silicon-containing co-polymer was prepared by the reaction of this tetra-coordinated silicon monomer with methyl acrylate via free radical polymerization. The tetra-coordinated silicon monomer and co-polymer were characterized by FTIR,EA,EDS,TG,DSC, GPC etc.The absorption band for C=C at 1630 cm-1 of the co-polymer disappeared,indicating that the co-polymerization was complete.The co-polymer began to decompose at 357℃;the glass transition temperature was 23.4℃between the PMA(Tg=8℃) and the homer-polymer of tetra-coordinated silicon(Tg=32.8℃);the molecular weight of the co-polymer was about 2.2×104,the dispersion coefficient was 1.76. The IR spectrum and the molecular weight of co-polymer were characterized after one year under moisture (RH=90%),and the results indicated no change,suggesting that the copolymer was stable.
High reactive penta-coordinated organic silicon was prepared by the reaction of silica with ethylene glycol and potassium hydroxide.Double bond tetra-coordinated silicon was produced by the reaction of this penta-coordinated silicon with 4-vinylbenzyl chloride;then branch-silicon-containing co-polymer was prepared by the reaction of this tetra-coordinated silicon monomer with methyl acrylate via free radical polymerization. The tetra-coordinated silicon monomer and co-polymer were characterized by FTIR,EA,EDS,TG,DSC, GPC etc.The absorption band for C=C at 1630 cm-1 of the co-polymer disappeared,indicating that the co-polymerization was complete.The co-polymer began to decompose at 357℃;the glass transition temperature was 23.4℃between the PMA(Tg=8℃) and the homer-polymer of tetra-coordinated silicon(Tg=32.8℃);the molecular weight of the co-polymer was about 2.2×104,the dispersion coefficient was 1.76. The IR spectrum and the molecular weight of co-polymer were characterized after one year under moisture (RH=90%),and the results indicated no change,suggesting that the copolymer was stable.
2007, 24(2): 178-182
Abstract:
A new complexing surfactant with the Schiff base structure was synthesized from p-Cresol,lauric acid and ethylenediamine by reactions of acylation,fries rearrangement,sulfonation and condensation.The total synthetic yield of the surfactant was 39.2%.The Cu2+ complex with this surfactant was also prepared in synthetic yield of 87.6%.The surface tension and foam height of the surfactant were tested at 20℃,CMC of the surfactant was 2.5×10-4mol/L,the lowest surface tension was 30 mN/m,which showed the surfactant has high surface activity.The stability constant of the complex was determined by spectrophotometric method to be 1.91×108 in borax buffer solution at 25℃.The experimental result revealed that the surfactant is easily coordinated with Cu2+ to form stable complex.Antibacterial test showed that the complex has a high antibacte-rial activity against E.coli,S.aureus and B.subtilis,especially against S.aureus with the minimum bacteri-cidal concentration at 96.1×10-6g/mL.
A new complexing surfactant with the Schiff base structure was synthesized from p-Cresol,lauric acid and ethylenediamine by reactions of acylation,fries rearrangement,sulfonation and condensation.The total synthetic yield of the surfactant was 39.2%.The Cu2+ complex with this surfactant was also prepared in synthetic yield of 87.6%.The surface tension and foam height of the surfactant were tested at 20℃,CMC of the surfactant was 2.5×10-4mol/L,the lowest surface tension was 30 mN/m,which showed the surfactant has high surface activity.The stability constant of the complex was determined by spectrophotometric method to be 1.91×108 in borax buffer solution at 25℃.The experimental result revealed that the surfactant is easily coordinated with Cu2+ to form stable complex.Antibacterial test showed that the complex has a high antibacte-rial activity against E.coli,S.aureus and B.subtilis,especially against S.aureus with the minimum bacteri-cidal concentration at 96.1×10-6g/mL.
2007, 24(2): 183-187
Abstract:
Ultrafine powder of spinel type ferrite Ni0.6Cu0.2 Zn0.2Fe2 O4 was prepared from Fe(NO3)3·9H2O, Ni(NO3)2·6H2O,Zn(NO3)2·6H2O,Cu(NO3)2·3H2O and citric acid via solid state reaction at low heating temperatures.The reaction mechanism and structure of the product were investigated by means of FT-IR,DTA-TG,XRD,TEM and SEM.The FT-IR results show that the metal ions could react with citric acid by grinding for 30 min,and the carboxyl groups of the citric acid were coordinated to the metal ions in a monodentate fashion.The XRD and FT-IR analyses for the samples sintered at different temperatures indicate that the spinel crystal structure integrates gradually with the increase of the calcination temperature.Accor-ding to the calculation via the Scherrer formula and the TEM analysis,the particle size of the ferrite was about 30~40 nm after the dried gel was decomposed at 350℃for 1 h,and the particle size increased to 200~300 nm when the decomposed dried gel sample was sintered at 900℃ for 2 h.
Ultrafine powder of spinel type ferrite Ni0.6Cu0.2 Zn0.2Fe2 O4 was prepared from Fe(NO3)3·9H2O, Ni(NO3)2·6H2O,Zn(NO3)2·6H2O,Cu(NO3)2·3H2O and citric acid via solid state reaction at low heating temperatures.The reaction mechanism and structure of the product were investigated by means of FT-IR,DTA-TG,XRD,TEM and SEM.The FT-IR results show that the metal ions could react with citric acid by grinding for 30 min,and the carboxyl groups of the citric acid were coordinated to the metal ions in a monodentate fashion.The XRD and FT-IR analyses for the samples sintered at different temperatures indicate that the spinel crystal structure integrates gradually with the increase of the calcination temperature.Accor-ding to the calculation via the Scherrer formula and the TEM analysis,the particle size of the ferrite was about 30~40 nm after the dried gel was decomposed at 350℃for 1 h,and the particle size increased to 200~300 nm when the decomposed dried gel sample was sintered at 900℃ for 2 h.
2007, 24(2): 188-191
Abstract:
NiCoCr-Al2O3 foam alloy was electrodeposited,the effects of the composition of solution on the properties of foam alloy were studied.The contents of Cr and Al2O3 in the alloy increase with the increases of concentrations of CrCl3·6H2O and Al2O3 in bath,the alloy surface changes to black when Cr in the alloy is over 6.8%;the alloy becomes fragile when Al2O3 in the alloy is over 8.1%.It is foudn that only when the temperature was higher than 852.37℃did the phase which is propitious to antioxidation at high temperatures appear.The effects of treatment temperature on the antioxidation of the alloy at high temperatures were investi-gated,the mass gain was the lowest after the alloy was treated at 1200℃.The effects of chromium and aluminium contents on the antioxidation of the alloy at high temperatures were also studied,the antioxidation of the alloy was improved with increasing the amount of Cr and Al2O3 in the alloy.It is found that Al2O3 promo-ted the antioxidation of the alloy.
NiCoCr-Al2O3 foam alloy was electrodeposited,the effects of the composition of solution on the properties of foam alloy were studied.The contents of Cr and Al2O3 in the alloy increase with the increases of concentrations of CrCl3·6H2O and Al2O3 in bath,the alloy surface changes to black when Cr in the alloy is over 6.8%;the alloy becomes fragile when Al2O3 in the alloy is over 8.1%.It is foudn that only when the temperature was higher than 852.37℃did the phase which is propitious to antioxidation at high temperatures appear.The effects of treatment temperature on the antioxidation of the alloy at high temperatures were investi-gated,the mass gain was the lowest after the alloy was treated at 1200℃.The effects of chromium and aluminium contents on the antioxidation of the alloy at high temperatures were also studied,the antioxidation of the alloy was improved with increasing the amount of Cr and Al2O3 in the alloy.It is found that Al2O3 promo-ted the antioxidation of the alloy.
2007, 24(2): 192-195
Abstract:
A novel glucose sensor without enzyme was prepared based on the electrochemical oxidation of glucose at a nickel electrode.The mechanism of electrochemical oxidation and response of the sensor to glucose was investigated.In the alkaline solution,the Ni(Ⅲ) species of nickel electrode surface acts as a oxidant for the oxidation of glucose,the glucose is quickly oxidized to glucolactone by the Ni(Ⅲ) species, resulting to the increase of current,which can quantify the concentrations of glucose.The sensor was composed of a nickel rod working electrode,a platinum counter electrode and an Ag/AgCl reference elec-trode.The wave potential of the electrochemical oxidation at 570 mV was employed as the working potential of the sensor.The response time of the sensor is less than 60 seconds and the time of monitoring a sample is 3 minutes.The current response of the sensor is proportional to the concentration of glucose,the detecting range is from 1.96×10-5 to 1.80×10-4mol/L,with a detection limit of 9.80×10-6mol/L.Because the sensor does not contain enzyme,the effect of temperature is less and oxygen in sample does not affect the determination of glucose.Dopamine,ascorbic acid and urea acid do not interfere with the determination of glucose due to their inactivation at nickel electrode.The sensor has been applied to the determination of prac-tical samples,the relative standard deviation(RSD) is less than 4.3%(n=5) for the determination of glucose in human blood serum and the result is consistent with that from the hexokinase method.The preparation of the sensor is simple and has a lower cost,as well as it can be repeatedly used after simple treatment.
A novel glucose sensor without enzyme was prepared based on the electrochemical oxidation of glucose at a nickel electrode.The mechanism of electrochemical oxidation and response of the sensor to glucose was investigated.In the alkaline solution,the Ni(Ⅲ) species of nickel electrode surface acts as a oxidant for the oxidation of glucose,the glucose is quickly oxidized to glucolactone by the Ni(Ⅲ) species, resulting to the increase of current,which can quantify the concentrations of glucose.The sensor was composed of a nickel rod working electrode,a platinum counter electrode and an Ag/AgCl reference elec-trode.The wave potential of the electrochemical oxidation at 570 mV was employed as the working potential of the sensor.The response time of the sensor is less than 60 seconds and the time of monitoring a sample is 3 minutes.The current response of the sensor is proportional to the concentration of glucose,the detecting range is from 1.96×10-5 to 1.80×10-4mol/L,with a detection limit of 9.80×10-6mol/L.Because the sensor does not contain enzyme,the effect of temperature is less and oxygen in sample does not affect the determination of glucose.Dopamine,ascorbic acid and urea acid do not interfere with the determination of glucose due to their inactivation at nickel electrode.The sensor has been applied to the determination of prac-tical samples,the relative standard deviation(RSD) is less than 4.3%(n=5) for the determination of glucose in human blood serum and the result is consistent with that from the hexokinase method.The preparation of the sensor is simple and has a lower cost,as well as it can be repeatedly used after simple treatment.
2007, 24(2): 196-199
Abstract:
The radical copolymerizations of diethyldiallylammonium chloride(DEDAAC) with acrylamide (AM),acrylic acid(AA) or sodium acrylic acid(AANa) were carried out in aqueous solutions using persul-fate ammonium(APS) as initiator.The compositions of these copolymers at various monomer molar ratios and with low conversion were determined by elemental analysis and the corresponding composition curves were plotted.The reactivity ratios of monomers in copolymerization were also obtained by Kelen-Tudos method.The results show that the values of reactivity ratios r and r are 0.31 and 5.27 for DEDAAC with AM,0.28 and 5.15 for DEDAAC with AA,and 0.40 and 3.97 for DEDAAC with AANa.The molar fractions of the unit of DEDAAC in copolymers are lower than those in monomer mixtures and the reactivity of DEDAAC is far lower than those of AM,AA and AANa,and this is probably due to the strong chain transfer,self inhibition,and the large steric hindrance of DEDAAC,as well as the large end effect and penultimate effect between the growing chains and DEDAAC.For each system above,the product of the reactivity ratios of the two monomers is above 1,therefore,the copolymerization for DEDAAC with AM,AA or AANa is non-ideal copolymerization and the products are approximately random copolymers.
The radical copolymerizations of diethyldiallylammonium chloride(DEDAAC) with acrylamide (AM),acrylic acid(AA) or sodium acrylic acid(AANa) were carried out in aqueous solutions using persul-fate ammonium(APS) as initiator.The compositions of these copolymers at various monomer molar ratios and with low conversion were determined by elemental analysis and the corresponding composition curves were plotted.The reactivity ratios of monomers in copolymerization were also obtained by Kelen-Tudos method.The results show that the values of reactivity ratios r and r are 0.31 and 5.27 for DEDAAC with AM,0.28 and 5.15 for DEDAAC with AA,and 0.40 and 3.97 for DEDAAC with AANa.The molar fractions of the unit of DEDAAC in copolymers are lower than those in monomer mixtures and the reactivity of DEDAAC is far lower than those of AM,AA and AANa,and this is probably due to the strong chain transfer,self inhibition,and the large steric hindrance of DEDAAC,as well as the large end effect and penultimate effect between the growing chains and DEDAAC.For each system above,the product of the reactivity ratios of the two monomers is above 1,therefore,the copolymerization for DEDAAC with AM,AA or AANa is non-ideal copolymerization and the products are approximately random copolymers.
2007, 24(2): 200-205
Abstract:
Nine compounds of lateral single fluorine substituted 4,4'-bis(trans-4-n-alkylcyclohexyl) biphenyl liquid crystals were synthesized via Suzuki coupling reactions with 2-fluoro-4-(trans-4-alkylcyclohexyl) phenyl boric acid and(trans-4-n-alkylcyclohexyl)-bromo benzene as reactants.The purity of the products was more than 99.9%,and the yields were 28.0%~88.9%.Their structures were confirmed by means of~1H NMR, IR and MS.The phase transition behavior was studied through differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).The results show that all the compounds possess a wide temperature range of mesophases,the narrowest temperature range of mesophases is 138℃and the widest is 201℃.The smectic phase temperature range was dramatically reduced or disappeared,and the nematic phase temperature range was enlarged because of the introduction of lateral single fluorine.
Nine compounds of lateral single fluorine substituted 4,4'-bis(trans-4-n-alkylcyclohexyl) biphenyl liquid crystals were synthesized via Suzuki coupling reactions with 2-fluoro-4-(trans-4-alkylcyclohexyl) phenyl boric acid and(trans-4-n-alkylcyclohexyl)-bromo benzene as reactants.The purity of the products was more than 99.9%,and the yields were 28.0%~88.9%.Their structures were confirmed by means of~1H NMR, IR and MS.The phase transition behavior was studied through differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).The results show that all the compounds possess a wide temperature range of mesophases,the narrowest temperature range of mesophases is 138℃and the widest is 201℃.The smectic phase temperature range was dramatically reduced or disappeared,and the nematic phase temperature range was enlarged because of the introduction of lateral single fluorine.
2007, 24(2): 206-209
Abstract:
Bi38ZnO58,a photocatalyst responsive to the sunlight,was successfully synthesized by means of solid state reaction method at 700℃,and Bi(NO3)3·5H2O and ZnCl2 were used as the reactants.The cubic crystal structure of the photocatalyst was determined by means of XRD.SEM and TEM indicated that Bi38ZnO58 were spherical particles with good dispersity and the average diameter was ca.100 nm.The photo-absorption property and band gap of the photoeatalyst were determined by UV-Vis diffuse reflectance spectrum, from which it could be seen that the band energy of the photocatalyst was ca.2.13 eV,and that Bi38ZnO58 possessed much strong photo-absorption property both in the ultraviolet and visible light regions.The edge position of the VB of the photocatalyst was calculated roughly as ca.2.6 eV,which demonstrated that the photocatalyst had a much strong oxidative activity.The photocatalytie activity of Bi38ZnO58 was tested on 12 mg/L methylene blue solution under sunlight illumination.The test results showed that methylene blue was nearly completely degraded after 4 h,which confirmed the high photocatalytic activity of the photocatalyst. Moreover,the crystal structure of Bi38ZnO58 was still the same and its photocatalytic efficiency of Bi38ZnO58 was still above 98% even after being reused for five times.
Bi38ZnO58,a photocatalyst responsive to the sunlight,was successfully synthesized by means of solid state reaction method at 700℃,and Bi(NO3)3·5H2O and ZnCl2 were used as the reactants.The cubic crystal structure of the photocatalyst was determined by means of XRD.SEM and TEM indicated that Bi38ZnO58 were spherical particles with good dispersity and the average diameter was ca.100 nm.The photo-absorption property and band gap of the photoeatalyst were determined by UV-Vis diffuse reflectance spectrum, from which it could be seen that the band energy of the photocatalyst was ca.2.13 eV,and that Bi38ZnO58 possessed much strong photo-absorption property both in the ultraviolet and visible light regions.The edge position of the VB of the photocatalyst was calculated roughly as ca.2.6 eV,which demonstrated that the photocatalyst had a much strong oxidative activity.The photocatalytie activity of Bi38ZnO58 was tested on 12 mg/L methylene blue solution under sunlight illumination.The test results showed that methylene blue was nearly completely degraded after 4 h,which confirmed the high photocatalytic activity of the photocatalyst. Moreover,the crystal structure of Bi38ZnO58 was still the same and its photocatalytic efficiency of Bi38ZnO58 was still above 98% even after being reused for five times.
2007, 24(2): 210-214
Abstract:
The solid-phase extraction and capillary gas chromatography(SPE-CGC) was introduced for the determination of 19 kinds of organochlorine pesticide residues including 4 isomers of hexachlorocyclohexane (BHC)(α-BHC,β-BHC,γ-BHC,δ-BHC);5 isomers of 4,4'-dichl-orodiphenyhhrichloroethane,(DDT)(pp'-DDE,pp'-DDD,op'-DDT,op'-DDE and pp'-DDT);tetra,penta-chloroaniline;heXachlorobenzene; heptachlor;quintozene;chlor-othalonil;heptachlor epoxide;aldrin;dieldrin and endlrin in preserved ginseng,ginseng honey plate and ginseng tea.The organochlorine pesticides were extracted form the samples with the solvents of the mixture of petrolic-aether acetone,followed by the purification with SPEC10 solid-phase extraction column.Then the extract was separated by using gas chromatography and OV-1701 flexible quartz capillary(25 m×0.25 mm×0.5μm) chromatographic column.Sample was detected by 63Ni electron capture detector(ECD) with N2(99.99%) as the carrier gas.The temperatures of the injector and detector were both at 300℃and increased automatically.The good linearity were obtained for the 19 kinds of organi-chlorine pesticides with the average relative coefficient larger than 0.992.The minim detectable sample wasl.5×1013~2.5×1012g,and the average recoveries range was from 73.7% to 96.6%.
The solid-phase extraction and capillary gas chromatography(SPE-CGC) was introduced for the determination of 19 kinds of organochlorine pesticide residues including 4 isomers of hexachlorocyclohexane (BHC)(α-BHC,β-BHC,γ-BHC,δ-BHC);5 isomers of 4,4'-dichl-orodiphenyhhrichloroethane,(DDT)(pp'-DDE,pp'-DDD,op'-DDT,op'-DDE and pp'-DDT);tetra,penta-chloroaniline;heXachlorobenzene; heptachlor;quintozene;chlor-othalonil;heptachlor epoxide;aldrin;dieldrin and endlrin in preserved ginseng,ginseng honey plate and ginseng tea.The organochlorine pesticides were extracted form the samples with the solvents of the mixture of petrolic-aether acetone,followed by the purification with SPEC10 solid-phase extraction column.Then the extract was separated by using gas chromatography and OV-1701 flexible quartz capillary(25 m×0.25 mm×0.5μm) chromatographic column.Sample was detected by 63Ni electron capture detector(ECD) with N2(99.99%) as the carrier gas.The temperatures of the injector and detector were both at 300℃and increased automatically.The good linearity were obtained for the 19 kinds of organi-chlorine pesticides with the average relative coefficient larger than 0.992.The minim detectable sample wasl.5×1013~2.5×1012g,and the average recoveries range was from 73.7% to 96.6%.
2007, 24(2): 215-219
Abstract:
The total synthesis of(s)-(+)-tylophorine,an anti-tumor active compound,was completed via eight-step reactions using veratraldehyde(1),3,4-dimethoxyphenylacetic acid(2) and(S)-L-proline(6),as raw materials.In the procedure,3,4-dimethoxy-trans-α-(3',4'-dimethoxyphenyl) phenylcinnamic acid(3) was synthesized by the reaction of veratraldehyde and 3,4-dimethoxyphenylacetic acid in the presence of acetic anhydride/Et3N and then oxidative coupling reaction using VOF3 to form 2,3,6,7-tetramethoxyphenanthrene-9-carboxylic acid(4) at 0℃.The intermediate(4) in quinoline derived 2,3,6,7-tetramethoxyphenanthrene (5) via decarboxylation catalyzed by anhydrous CuSO4 at 230℃.The Friedel-Crafts reaction of the intermedi-ate(5) with(S)-N-(trifluoroacetyl) prolyl chloride(6b) formed(S)-N-(trifluoroacetyl) 2,3,6,7-tetrame-thoxy-9-prolyl-phenanthrene(7).After purification on a silica gel column,the carbonyl group of the interme-diate(7) was reduced by triethylsilane in presence of BF3·Et2O at room temperature,and then the detriflu-oroacetylation was followed.Finally,a ring-closing reaction with formaldehyde gave the target compound(10) in the presence of hydrochloric acid.The intermediates and target compounds were characterized by NMR and MS spectra.The synthetic conditions were mild,the total yield and the purity of the target compounds were 3.5% and 98.5%(HPLC),respectively.
The total synthesis of(s)-(+)-tylophorine,an anti-tumor active compound,was completed via eight-step reactions using veratraldehyde(1),3,4-dimethoxyphenylacetic acid(2) and(S)-L-proline(6),as raw materials.In the procedure,3,4-dimethoxy-trans-α-(3',4'-dimethoxyphenyl) phenylcinnamic acid(3) was synthesized by the reaction of veratraldehyde and 3,4-dimethoxyphenylacetic acid in the presence of acetic anhydride/Et3N and then oxidative coupling reaction using VOF3 to form 2,3,6,7-tetramethoxyphenanthrene-9-carboxylic acid(4) at 0℃.The intermediate(4) in quinoline derived 2,3,6,7-tetramethoxyphenanthrene (5) via decarboxylation catalyzed by anhydrous CuSO4 at 230℃.The Friedel-Crafts reaction of the intermedi-ate(5) with(S)-N-(trifluoroacetyl) prolyl chloride(6b) formed(S)-N-(trifluoroacetyl) 2,3,6,7-tetrame-thoxy-9-prolyl-phenanthrene(7).After purification on a silica gel column,the carbonyl group of the interme-diate(7) was reduced by triethylsilane in presence of BF3·Et2O at room temperature,and then the detriflu-oroacetylation was followed.Finally,a ring-closing reaction with formaldehyde gave the target compound(10) in the presence of hydrochloric acid.The intermediates and target compounds were characterized by NMR and MS spectra.The synthetic conditions were mild,the total yield and the purity of the target compounds were 3.5% and 98.5%(HPLC),respectively.
2007, 24(2): 220-222
Abstract:
Eight compounds were isolated from the mangrove endophytie fungus Cephalosporium sp.from the South China Sea.Their structures were elucidated by spectral data.It is the first time for 6,8-dihydroxy-4-[(1S)-1-hydroxyethyl]-isocoumarin and(3R,6R)-4-methyl-6-(1-methylethyl)-3-phenylmethyl-1,4-per-hydrooxazine-2,5-dione to be isolated from the fungus Cephalosporium sp.
Eight compounds were isolated from the mangrove endophytie fungus Cephalosporium sp.from the South China Sea.Their structures were elucidated by spectral data.It is the first time for 6,8-dihydroxy-4-[(1S)-1-hydroxyethyl]-isocoumarin and(3R,6R)-4-methyl-6-(1-methylethyl)-3-phenylmethyl-1,4-per-hydrooxazine-2,5-dione to be isolated from the fungus Cephalosporium sp.
2007, 24(2): 223-225
Abstract:
(3S,4S)-N-benzyl-3,4-dihydroxy pyrrolidine was synthesized using NaBH4/I2 as the reducing agent in THF.The effect of the molar ratio of the starting materials,the reaction time,and the type of reducting agents were explored.Under the optimum condition,i.e.,the molar ratio of substrate to NaBH4 and I2 was 1:5:1.67,and the refluxing reaction time was 6 h,the yield was up to 70%.The product was charac-terized by 1H and 13C NMR spectroscopy,and all the results were consistent with the compounds synthesized. Compared with the conventional synthetic method,the method has such advantages as inexpensive reagents, simple operation,and easy scaling up.
(3S,4S)-N-benzyl-3,4-dihydroxy pyrrolidine was synthesized using NaBH4/I2 as the reducing agent in THF.The effect of the molar ratio of the starting materials,the reaction time,and the type of reducting agents were explored.Under the optimum condition,i.e.,the molar ratio of substrate to NaBH4 and I2 was 1:5:1.67,and the refluxing reaction time was 6 h,the yield was up to 70%.The product was charac-terized by 1H and 13C NMR spectroscopy,and all the results were consistent with the compounds synthesized. Compared with the conventional synthetic method,the method has such advantages as inexpensive reagents, simple operation,and easy scaling up.
2007, 24(2): 226-228
Abstract:
The antimony oxychloride was synthesized by means of electrochemical method.The anode comprised of sacrificial metal Sb;the cathode was an indifferent conducting material;the electrolyte could be a chloride salt soluble in the hydrochloric acid.Uhrafine metal Sb(10nm) was directly prepared by elec-trosynthesis,and antimony oxychloride was synthesized through hydrolyzing antimony chloride solution which was formed by the reaction of ultrafine Sb and hydrochloric acid.The synthetic condition was discussed and the structure and morphology of the product were characterized by virtue of titration,XRD,SEM and TEM.The synthetic process is simple without contamination.
The antimony oxychloride was synthesized by means of electrochemical method.The anode comprised of sacrificial metal Sb;the cathode was an indifferent conducting material;the electrolyte could be a chloride salt soluble in the hydrochloric acid.Uhrafine metal Sb(10nm) was directly prepared by elec-trosynthesis,and antimony oxychloride was synthesized through hydrolyzing antimony chloride solution which was formed by the reaction of ultrafine Sb and hydrochloric acid.The synthetic condition was discussed and the structure and morphology of the product were characterized by virtue of titration,XRD,SEM and TEM.The synthetic process is simple without contamination.
2007, 24(2): 229-231
Abstract:
A method for the enantioseparation of Hexythiazox via capillary electrophoresis with conductive detection was developed.The enantiomers of Hexythiazox were baseline separated within 10 min under the following separation conditions:uncoated fused silica capillary(45 cm×75μm,i.d.),5 mmol/L NaAc+ 2 mmol/L HAc+5 mmol/L β-CD(pH=4.0)+V(methanol):V(N,N-Dimethylformamide) =8:2 as running buffer,15 kV separation voltage.The effect of running buffer,pH,the concentration of chiral selector,sepa-ration voltage and inject time were discussed in detail.A linearity was found between peak height(y) and mass concentration of Hexythiazox(x) in a range of 8.0~160 mg/L with a regression equation of y=9.4+36.8x,and the correlation coefficient was 0.996 3,and the determination limit was 1.6 mg/L.
A method for the enantioseparation of Hexythiazox via capillary electrophoresis with conductive detection was developed.The enantiomers of Hexythiazox were baseline separated within 10 min under the following separation conditions:uncoated fused silica capillary(45 cm×75μm,i.d.),5 mmol/L NaAc+ 2 mmol/L HAc+5 mmol/L β-CD(pH=4.0)+V(methanol):V(N,N-Dimethylformamide) =8:2 as running buffer,15 kV separation voltage.The effect of running buffer,pH,the concentration of chiral selector,sepa-ration voltage and inject time were discussed in detail.A linearity was found between peak height(y) and mass concentration of Hexythiazox(x) in a range of 8.0~160 mg/L with a regression equation of y=9.4+36.8x,and the correlation coefficient was 0.996 3,and the determination limit was 1.6 mg/L.
2007, 24(2): 232-234
Abstract:
2,4,6-Trimethylbenzaldehyde(4) was synthesized from mesitylene via nitration,reduction,diazo-tization and treatment with formaldoxime in an overall yield of about 37.82% with a purity of 98%.Reaction of 1,3,5-mesitylene with a mixed acid of fuming nitric acid and glacial acetic acid in acetic anhydride at 5℃gave 2,4,6-trimethylnitrobenzene(1) with a yield of 90.6%,which was reduced by Fe and hydrochloric acid in a mixed solvent of water and ethanol to give 2,4,6-trimethylaniline(2) with a yield of 80.27%.Diazo reaction of compound 2 gave diazonium salt(3),which was then dropped into a solution of fresh formaldo-xime,CuSO4 and Na2SO3.The product was distilled,giving 2,4,6-trimethylbenzaldehyde(4) in a yield of 52%.The structure of the target compound was confirmed by means of MS and 1H NMR.
2,4,6-Trimethylbenzaldehyde(4) was synthesized from mesitylene via nitration,reduction,diazo-tization and treatment with formaldoxime in an overall yield of about 37.82% with a purity of 98%.Reaction of 1,3,5-mesitylene with a mixed acid of fuming nitric acid and glacial acetic acid in acetic anhydride at 5℃gave 2,4,6-trimethylnitrobenzene(1) with a yield of 90.6%,which was reduced by Fe and hydrochloric acid in a mixed solvent of water and ethanol to give 2,4,6-trimethylaniline(2) with a yield of 80.27%.Diazo reaction of compound 2 gave diazonium salt(3),which was then dropped into a solution of fresh formaldo-xime,CuSO4 and Na2SO3.The product was distilled,giving 2,4,6-trimethylbenzaldehyde(4) in a yield of 52%.The structure of the target compound was confirmed by means of MS and 1H NMR.
2007, 24(2): 235-237
Abstract:
Optically active(R)-and(S)-α-methyl-p-methoxy-phenylalanine were synthesized by electro-philic alkylation of Ni(Ⅱ) complexes of alanine Schiff base with p-methoxybenzyl chloride.The effect of base on the stereoselectivity of the reaction was investigated.The optimal reaction conditions were that the molar ratio of Ni(Ⅱ) complexes of alanine Schiff base to p-methoxybeznyl chloride was 1:1.1,and reaction time was 2 h.The yields of(R)-and(S)-α-methyl-p-methoxy-phenylalanines were 71.3% and 70.9%,respec-tively,and the e.e.was up to 97.5%.Chiral auxiliary 2-[N-(N'-benzylprolyl)]-aminobenzophenone was recovered in a 90% to 95% yield without any loss of the optical purity.The products were characterized by NMR and optical rotation.
Optically active(R)-and(S)-α-methyl-p-methoxy-phenylalanine were synthesized by electro-philic alkylation of Ni(Ⅱ) complexes of alanine Schiff base with p-methoxybenzyl chloride.The effect of base on the stereoselectivity of the reaction was investigated.The optimal reaction conditions were that the molar ratio of Ni(Ⅱ) complexes of alanine Schiff base to p-methoxybeznyl chloride was 1:1.1,and reaction time was 2 h.The yields of(R)-and(S)-α-methyl-p-methoxy-phenylalanines were 71.3% and 70.9%,respec-tively,and the e.e.was up to 97.5%.Chiral auxiliary 2-[N-(N'-benzylprolyl)]-aminobenzophenone was recovered in a 90% to 95% yield without any loss of the optical purity.The products were characterized by NMR and optical rotation.
2007, 24(2): 238-240
Abstract:
LiFePO4 composites obtained with sucrose or acetylene black coating processing were prepared via high temperature solid-state reaction.The crystalline structures,morphologies of the particles,and electro-chemical performance of the samples were investigated by X-ray diffraction,scanning electron microscopy,and charge-discharge test.The results show that LiFePO4 composites were simple olive-type phase.Electrochemi-cal tests showed that LiFePO4 composites obtained with sucrose coating processing possessed excellent electro-chemical performance,the first specific discharge capacity of which was 148.6 mA·h/g during charge and discharge at 0.2C,and even after 20 times cycling,the discharge capacity was 140.3 mA·h/g.
LiFePO4 composites obtained with sucrose or acetylene black coating processing were prepared via high temperature solid-state reaction.The crystalline structures,morphologies of the particles,and electro-chemical performance of the samples were investigated by X-ray diffraction,scanning electron microscopy,and charge-discharge test.The results show that LiFePO4 composites were simple olive-type phase.Electrochemi-cal tests showed that LiFePO4 composites obtained with sucrose coating processing possessed excellent electro-chemical performance,the first specific discharge capacity of which was 148.6 mA·h/g during charge and discharge at 0.2C,and even after 20 times cycling,the discharge capacity was 140.3 mA·h/g.
