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2009 Volume 26 Issue 7
2009, 26(7): 749-752
Abstract:
This article reports a method for the synthesis of D-glucoheptulose by catalyzing carbon-skeleton rearrangement in the system of MoO3 aqueous solution.Firstly,2,3:5,6-Di-O-isopropylidene-D-mannose was prepared from D-mannose as starting material under the catalyst of iodine,with a yield of 90%.Secondly,hydroxymethylation on the C-2 of 2,3:5,6-Di-O-isopropylidene-D-mannose occurred with formaldehyde aqueous solution under base condition,with a yield of 40%.Thirdly,2-C-hydroxymethyl-D-mannose was prepared through the deprotection of isopropyaltion reaction under acid condition with a yield of 92%.And finally,D-glucoheptulose was synthesized by molybdic acid-catalyzed carbon-skeleton rearrangement with a yield of 56%(total yield 18%).In addition,the acetylated products of 2-C-hydroxymethyl-D-mannose and D-glucoheptulose were characterized by 1H NMR.The advantages of the method includ readily acquiring of materials,simplifying of the reaction procedures,and avoiding the application of expensive metal reagents with a good foreground of industrial application.
This article reports a method for the synthesis of D-glucoheptulose by catalyzing carbon-skeleton rearrangement in the system of MoO3 aqueous solution.Firstly,2,3:5,6-Di-O-isopropylidene-D-mannose was prepared from D-mannose as starting material under the catalyst of iodine,with a yield of 90%.Secondly,hydroxymethylation on the C-2 of 2,3:5,6-Di-O-isopropylidene-D-mannose occurred with formaldehyde aqueous solution under base condition,with a yield of 40%.Thirdly,2-C-hydroxymethyl-D-mannose was prepared through the deprotection of isopropyaltion reaction under acid condition with a yield of 92%.And finally,D-glucoheptulose was synthesized by molybdic acid-catalyzed carbon-skeleton rearrangement with a yield of 56%(total yield 18%).In addition,the acetylated products of 2-C-hydroxymethyl-D-mannose and D-glucoheptulose were characterized by 1H NMR.The advantages of the method includ readily acquiring of materials,simplifying of the reaction procedures,and avoiding the application of expensive metal reagents with a good foreground of industrial application.
2009, 26(7): 753-756
Abstract:
Hexa[p-(carboxyl) phenoxy]cyclotriphosphazene(HCPCP) was synthesized via two steps.Firstly,hexa[p-(aldehyde) phenoxy]cyclotriphosphazene(HAPCP) was obtained via a nucleophilic substitution of hexachlorocyclotriphosphazene with 4-hydroxybenzaldehyde.Then HCPCP was synthesized via potassium permanganate oxidation and characterized by infrared spectroscopy(IR),high performance liquid chromography(HPLC),nuclear magnetic resonance(NMR) and elemental analysis.Thermal properties of the macromolecule were investigated by thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC).With the addition of 30%HCPCP,the limiting oxygen index(LOI) of ABS was increased to 25%.
Hexa[p-(carboxyl) phenoxy]cyclotriphosphazene(HCPCP) was synthesized via two steps.Firstly,hexa[p-(aldehyde) phenoxy]cyclotriphosphazene(HAPCP) was obtained via a nucleophilic substitution of hexachlorocyclotriphosphazene with 4-hydroxybenzaldehyde.Then HCPCP was synthesized via potassium permanganate oxidation and characterized by infrared spectroscopy(IR),high performance liquid chromography(HPLC),nuclear magnetic resonance(NMR) and elemental analysis.Thermal properties of the macromolecule were investigated by thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC).With the addition of 30%HCPCP,the limiting oxygen index(LOI) of ABS was increased to 25%.
2009, 26(7): 757-761
Abstract:
Composites of rare-earth metal complexes supported on caprolactam-cation-based Bronsted acid ionic liquids(IL) were prepared,and used as solvents and catalysts in the nitration of toluene by equiv mole of 67% nitric acid.The structure of the ionic liquid was characterized by 1H NMR.The effects of reaction temperature,reaction time and the type and amount of catalyst on product yield and para-selectivity for the nitration of toluene were investigated.Nitrotoluene with a yield of 46.5% and an ortho-para isomer ratio of 1.1 was obtained under the optimal conditions.In addition,the mixture of IL and rare-earth complexes could be removed easily and recycled 4 times with the same ortho-para selectivity and only a small decrease in the yield,suggesting a possibility of a more economic and green process.
Composites of rare-earth metal complexes supported on caprolactam-cation-based Bronsted acid ionic liquids(IL) were prepared,and used as solvents and catalysts in the nitration of toluene by equiv mole of 67% nitric acid.The structure of the ionic liquid was characterized by 1H NMR.The effects of reaction temperature,reaction time and the type and amount of catalyst on product yield and para-selectivity for the nitration of toluene were investigated.Nitrotoluene with a yield of 46.5% and an ortho-para isomer ratio of 1.1 was obtained under the optimal conditions.In addition,the mixture of IL and rare-earth complexes could be removed easily and recycled 4 times with the same ortho-para selectivity and only a small decrease in the yield,suggesting a possibility of a more economic and green process.
2009, 26(7): 762-765
Abstract:
1-(6-Benzoyl-9-allyl-9.H.-carbazol-3-yl) -butane-1-one oxime O-ethyrate was synthesed by Friedel-Crafts acylation,oximation and esterification from N-allylcarbazole.As the key step of the synthesis,the optimal operation of Friedel-Crafts acylation was established by orthogonal experiment.For the 0.02 mol N-allylcarbazole,molar ratio of catalyst to reactants n(AlCl3)/n(N-allylcarbazole) was 1.10,molar ratio of reactants n(benzoic cloride)/n(N-allylcarbazole) was 1.15,and the reaction was carried out at 25 ℃ for 3 h.The average yield was 94.2%.The structure of the target compound was characterized by 1H NMR,UV,IR and elemental analysis.Photoinitiability of the compound was investigated comparing with the commercial product.
1-(6-Benzoyl-9-allyl-9.H.-carbazol-3-yl) -butane-1-one oxime O-ethyrate was synthesed by Friedel-Crafts acylation,oximation and esterification from N-allylcarbazole.As the key step of the synthesis,the optimal operation of Friedel-Crafts acylation was established by orthogonal experiment.For the 0.02 mol N-allylcarbazole,molar ratio of catalyst to reactants n(AlCl3)/n(N-allylcarbazole) was 1.10,molar ratio of reactants n(benzoic cloride)/n(N-allylcarbazole) was 1.15,and the reaction was carried out at 25 ℃ for 3 h.The average yield was 94.2%.The structure of the target compound was characterized by 1H NMR,UV,IR and elemental analysis.Photoinitiability of the compound was investigated comparing with the commercial product.
Preparation of Aliphatic/Aromatic Copolyesters Based on Cyclohexanedimethanol and Oligo(lactic acid)
2009, 26(7): 766-769
Abstract:
A new series of biodegradable copolyesters,PHCTL,were synthesized via polycondensation from dimethyl terephthalate(DMT),1,6-hexanediol(HDO),1,4-cyclohexanedimethanol(CHDM) and oligo(lactic acid) (OLA) in the presence of activator tetrabutyl titanate.The resulting copolyesters,PHCTL,were characterized by 1H NMR,differential scanning calorimetry(DSC),thermogravimetry(TG) and wide-angle X-ray scattering(WAXS).The melting temperature(Tm) and thermal decomposition temperature(Td) of the copolyesters increased obviously with increased of the CHDM content.In comparison with the copolyesters without CHDM involved,the Tm and Td of the copolyesters with a feeding ratio of 50/50 CHDM/HDO increased from 129 ℃ and 361 ℃ to 219 ℃ and 383 ℃,respectively.The molecular mass of the copolyesters varied in a range of 1.7×104~3.6×104 g/mol.The copolyesters were distinctly degraded in phosphate buffer solution at 37 ℃(10% mass loss after 10 days,7% for PHTL).The degradation rates of the copolyesters were dependent on their hydrophilicity.The Young module of PHCTL is 242 MPa.
A new series of biodegradable copolyesters,PHCTL,were synthesized via polycondensation from dimethyl terephthalate(DMT),1,6-hexanediol(HDO),1,4-cyclohexanedimethanol(CHDM) and oligo(lactic acid) (OLA) in the presence of activator tetrabutyl titanate.The resulting copolyesters,PHCTL,were characterized by 1H NMR,differential scanning calorimetry(DSC),thermogravimetry(TG) and wide-angle X-ray scattering(WAXS).The melting temperature(Tm) and thermal decomposition temperature(Td) of the copolyesters increased obviously with increased of the CHDM content.In comparison with the copolyesters without CHDM involved,the Tm and Td of the copolyesters with a feeding ratio of 50/50 CHDM/HDO increased from 129 ℃ and 361 ℃ to 219 ℃ and 383 ℃,respectively.The molecular mass of the copolyesters varied in a range of 1.7×104~3.6×104 g/mol.The copolyesters were distinctly degraded in phosphate buffer solution at 37 ℃(10% mass loss after 10 days,7% for PHTL).The degradation rates of the copolyesters were dependent on their hydrophilicity.The Young module of PHCTL is 242 MPa.
2009, 26(7): 770-774
Abstract:
Terpolymerization of glycidyl octanoate,carbon dioxide with propylene oxide was carried out using ternary rare-earth-metal coordination catalyst.IR,NMR and DSC results confirm the target polymer was a novel terpolymer.The glass transition temperature of the resoluting terpolymer decreased with increasing flexible glycidyl octanoate units,from 39.6 ℃ of carbon dioxide-propylene oxide copolymer to-12.30 ℃ of carbon dioxide-glycidyl octanoate copolymer,whereas the elongation at break at 20 ℃ increased from 31.0% to 983.9%.Introduction of 5.6% glycidyl octanoate unit into the terpolymer may raise the elongation at break to 481.1%,whereas the tensile strength maintains as high as 24.9 MPa.
Terpolymerization of glycidyl octanoate,carbon dioxide with propylene oxide was carried out using ternary rare-earth-metal coordination catalyst.IR,NMR and DSC results confirm the target polymer was a novel terpolymer.The glass transition temperature of the resoluting terpolymer decreased with increasing flexible glycidyl octanoate units,from 39.6 ℃ of carbon dioxide-propylene oxide copolymer to-12.30 ℃ of carbon dioxide-glycidyl octanoate copolymer,whereas the elongation at break at 20 ℃ increased from 31.0% to 983.9%.Introduction of 5.6% glycidyl octanoate unit into the terpolymer may raise the elongation at break to 481.1%,whereas the tensile strength maintains as high as 24.9 MPa.
2009, 26(7): 775-779
Abstract:
Nano-silica(SiO2) grafted poly(butyl acrylate) (PBA) (SiO2-g-PBA) via surface-initiated atom transfer radical polymerization(ATRP),and the modification of polyoxymethylene(POM) with SiO2-g-PBA nano composited particles were studied.The results of Fourier transform infrared(FT-IR) spectrometry,transmission electron microscopy(TEM),scanning electron microscopy(SEM),and thermogravimetic analysis(TGA) show that SiO2-g-PBA nano composited particles are more easily dispersed in the matrix than bare nano-SiO2.The impact property of POM/SiO2-g-PBA composites is improved.When the mass fraction of SiO2-g-PBA nano composited particles is 2%,the impact strength of the composited materials amounts to 71.2 kJ/m2,which is 7 times more than that of pure POM.Meantime,the tensile strength can also reach 68.1 MPa.
Nano-silica(SiO2) grafted poly(butyl acrylate) (PBA) (SiO2-g-PBA) via surface-initiated atom transfer radical polymerization(ATRP),and the modification of polyoxymethylene(POM) with SiO2-g-PBA nano composited particles were studied.The results of Fourier transform infrared(FT-IR) spectrometry,transmission electron microscopy(TEM),scanning electron microscopy(SEM),and thermogravimetic analysis(TGA) show that SiO2-g-PBA nano composited particles are more easily dispersed in the matrix than bare nano-SiO2.The impact property of POM/SiO2-g-PBA composites is improved.When the mass fraction of SiO2-g-PBA nano composited particles is 2%,the impact strength of the composited materials amounts to 71.2 kJ/m2,which is 7 times more than that of pure POM.Meantime,the tensile strength can also reach 68.1 MPa.
2009, 26(7): 780-785
Abstract:
With glutaraldehyde as the crosslinker,chymotrypsin was immobilized onto chitosan-arginine resin which was porous and grafted with a flexible and hydrophilic amino acid.The optimal conditions of immobilization are that the ratio of enzyme loading/wet resin(mg/g) is 20:1,concentration of glutaraldehyde solution is 1.0%,the dose is 10 mL,pH is 5.20,the activity is 850 U/g,and the immobilizing time is 60 min.The enzymatic properties of immobilized chymotrypsin are that the maximum rate is obtained within 30 min,and the catalysis time curve is similar to that of free enzyme;its Km value is 1.83 mmol/L,33.6% higher than that of free enzyme,and 24.0% lower than that of enzyme immobilized by crossing chitosan;its optimal temperature is 70 ℃,10 ℃ higher than that of free enzyme;its optimal pH is 5.92,which deviates 2 units to acid side compared with the free enzyme.Moreover,the immobilized chymotrypsin has a high thermal stability and storage stability,with a half-life of 6 h at 75 ℃ or 49 days at 4 ℃.
With glutaraldehyde as the crosslinker,chymotrypsin was immobilized onto chitosan-arginine resin which was porous and grafted with a flexible and hydrophilic amino acid.The optimal conditions of immobilization are that the ratio of enzyme loading/wet resin(mg/g) is 20:1,concentration of glutaraldehyde solution is 1.0%,the dose is 10 mL,pH is 5.20,the activity is 850 U/g,and the immobilizing time is 60 min.The enzymatic properties of immobilized chymotrypsin are that the maximum rate is obtained within 30 min,and the catalysis time curve is similar to that of free enzyme;its Km value is 1.83 mmol/L,33.6% higher than that of free enzyme,and 24.0% lower than that of enzyme immobilized by crossing chitosan;its optimal temperature is 70 ℃,10 ℃ higher than that of free enzyme;its optimal pH is 5.92,which deviates 2 units to acid side compared with the free enzyme.Moreover,the immobilized chymotrypsin has a high thermal stability and storage stability,with a half-life of 6 h at 75 ℃ or 49 days at 4 ℃.
2009, 26(7): 786-790
Abstract:
Resveratrol(RES) imprinted composite membranes,with polyvinylidene fluoride microporous membrane as supporting membrane,were synthesized via in situ polymerization by thermal initiation,using acrylamide(AM) as the functional monomer and ethyleneglycol dimethacrylate(EDMA) as the cross-linking agent.Scanning electron microscope(SEM) was used to visualize the surface of membranes.The binding ability and permeation selectivity were studied for RES and its analogues,polydatin(POL),bisphel A(BPA) and 2-naphthol.The results indicate that the imprinted membranes demonstrate satisfactory recognition capacity and selectivity towards the template molecules.Rebinding of RES was much higher than those of structurally similar compounds.The saturated binding capacity of the imprinted composite membrane for RES is about 1.72 μmol/g,nearly 3 times that of non-imprinted polymer membrane.2-Naphthol,which is smaller than the template molecule in size,permeates through the imprinted composite membrane preferentially.The permeation amounts of BPA and POL are both less than that of RES whether the molecular size is the same as or bigger than RES.RES permeates quickly through the imprinted membrane probably due to its compleme-ntary functional groups and shaping with the imprinted sites on the imprinted composite membrane.The RES transfer rate is increased through the imprinted composite membranes probably due to the larger amount of binding sites,compared with that through the non-imprinted one.
Resveratrol(RES) imprinted composite membranes,with polyvinylidene fluoride microporous membrane as supporting membrane,were synthesized via in situ polymerization by thermal initiation,using acrylamide(AM) as the functional monomer and ethyleneglycol dimethacrylate(EDMA) as the cross-linking agent.Scanning electron microscope(SEM) was used to visualize the surface of membranes.The binding ability and permeation selectivity were studied for RES and its analogues,polydatin(POL),bisphel A(BPA) and 2-naphthol.The results indicate that the imprinted membranes demonstrate satisfactory recognition capacity and selectivity towards the template molecules.Rebinding of RES was much higher than those of structurally similar compounds.The saturated binding capacity of the imprinted composite membrane for RES is about 1.72 μmol/g,nearly 3 times that of non-imprinted polymer membrane.2-Naphthol,which is smaller than the template molecule in size,permeates through the imprinted composite membrane preferentially.The permeation amounts of BPA and POL are both less than that of RES whether the molecular size is the same as or bigger than RES.RES permeates quickly through the imprinted membrane probably due to its compleme-ntary functional groups and shaping with the imprinted sites on the imprinted composite membrane.The RES transfer rate is increased through the imprinted composite membranes probably due to the larger amount of binding sites,compared with that through the non-imprinted one.
2009, 26(7): 791-794
Abstract:
A new room-temperature spin crossover complex [Fe(dpp) (Mepy) 2(NCS) 2] was prepared.Elemental analysis,infrared spectroscopy,electrospray ionization mass spectrometry and ultraviolet spectro-scopy were used to study the structure of the complex.The temperature dependence of magnetic susceptibility shows that the temperature of spin transition is 330 K.By comparing the complex with the other resemblant structural complexes,it shows that the modification of ligand ha a great influence on the critical temperature and hysteresis loop of spin crossover.
A new room-temperature spin crossover complex [Fe(dpp) (Mepy) 2(NCS) 2] was prepared.Elemental analysis,infrared spectroscopy,electrospray ionization mass spectrometry and ultraviolet spectro-scopy were used to study the structure of the complex.The temperature dependence of magnetic susceptibility shows that the temperature of spin transition is 330 K.By comparing the complex with the other resemblant structural complexes,it shows that the modification of ligand ha a great influence on the critical temperature and hysteresis loop of spin crossover.
2009, 26(7): 795-800
Abstract:
Two tetrathiafulvalene-based D-π-A diad compounds(6a,7a) were prepared from starting compound(1) via Vilsmeier formylation and Wittig reaction or cross-coupling reaction.To study the effect of the N-methyl,two N-methylated D-π-A diad analogues(6b,7b) were also synthesized from the interme-diate(2) via the same process.Their electrochemical and photophysical properties were studied with cyclic voltammetry and UV-Vis spectrometry,and theoretical calculations were carried out for their third-order nonlinear optical properties.Experimental results showed that the maximum absorption wavelengths of the target compounds were 325~383 nm and the results calculated showed that compounds 7a and 7b with a longer conjugated structure possessed better third-order nonliner susceptibilities,and their γ values were 5×10-33 esu at λ=1 064 nm.
Two tetrathiafulvalene-based D-π-A diad compounds(6a,7a) were prepared from starting compound(1) via Vilsmeier formylation and Wittig reaction or cross-coupling reaction.To study the effect of the N-methyl,two N-methylated D-π-A diad analogues(6b,7b) were also synthesized from the interme-diate(2) via the same process.Their electrochemical and photophysical properties were studied with cyclic voltammetry and UV-Vis spectrometry,and theoretical calculations were carried out for their third-order nonlinear optical properties.Experimental results showed that the maximum absorption wavelengths of the target compounds were 325~383 nm and the results calculated showed that compounds 7a and 7b with a longer conjugated structure possessed better third-order nonliner susceptibilities,and their γ values were 5×10-33 esu at λ=1 064 nm.
2009, 26(7): 801-806
Abstract:
The major chemical constituents of glycyrrhiza(glycyrrhizic acid,liquiritin) and ephedra(ephedrine and methephedrine) in the decoction of ephedra-glycyrrhiza were analyzed by high performance liquid chromatography(HPLC) and gas chromatography(GC),respectively.The influences of different parts of ephedra-glycyrrhiza on the auricular swelling of mice caused by dimethylbenzene were studied.This method can sensitively detect the difference between the single decoction of glycyrrhiza,ephedra and combined decoction of ephedra-glycyrrhiza.Compared to that of single decoction,the abundances of glycyrrhizic acid,liquiritin,ephedrine and methephedrine in the combined decoction of ephedra-glycyrrhiza were increased by 13.50%,-19.38%,14.52% and 64.0%,respectively.The anti-inflammatory ability of the combined decoction of ephedra-glycyrrhiza was higher than that of the single decoctions.
The major chemical constituents of glycyrrhiza(glycyrrhizic acid,liquiritin) and ephedra(ephedrine and methephedrine) in the decoction of ephedra-glycyrrhiza were analyzed by high performance liquid chromatography(HPLC) and gas chromatography(GC),respectively.The influences of different parts of ephedra-glycyrrhiza on the auricular swelling of mice caused by dimethylbenzene were studied.This method can sensitively detect the difference between the single decoction of glycyrrhiza,ephedra and combined decoction of ephedra-glycyrrhiza.Compared to that of single decoction,the abundances of glycyrrhizic acid,liquiritin,ephedrine and methephedrine in the combined decoction of ephedra-glycyrrhiza were increased by 13.50%,-19.38%,14.52% and 64.0%,respectively.The anti-inflammatory ability of the combined decoction of ephedra-glycyrrhiza was higher than that of the single decoctions.
2009, 26(7): 807-810
Abstract:
The adsorption of Cu2+ from aqueous solution by home-made carbonate hydroxylapatite(CHAP) synthesized from abandoned eggshell with urea as the addititive was characterized by FT-IR,SEM and EDS.Factors that might influence the adsorption performance were investigated,including pH values,temperature and adsorption period in aqueous solution.The results show that the molar ratio of Ca/P in CHAP and the specific surface area increased with the amount of urea,and the absorption capacity became greater because Ca/P ratio of CHAP was higher.Absorption capacity of CHAP(Ca/P ratio,1.80) for Cu2+ from aqueous solution reached 37.66 mg/g when pH was 7,the temperature was 40 ℃,the reaction time was 60 min.The distribution coefficient between solid phase and water increased with the increase of Ca/P ratio of CHAP,which improves the absorption capacity..
The adsorption of Cu2+ from aqueous solution by home-made carbonate hydroxylapatite(CHAP) synthesized from abandoned eggshell with urea as the addititive was characterized by FT-IR,SEM and EDS.Factors that might influence the adsorption performance were investigated,including pH values,temperature and adsorption period in aqueous solution.The results show that the molar ratio of Ca/P in CHAP and the specific surface area increased with the amount of urea,and the absorption capacity became greater because Ca/P ratio of CHAP was higher.Absorption capacity of CHAP(Ca/P ratio,1.80) for Cu2+ from aqueous solution reached 37.66 mg/g when pH was 7,the temperature was 40 ℃,the reaction time was 60 min.The distribution coefficient between solid phase and water increased with the increase of Ca/P ratio of CHAP,which improves the absorption capacity..
2009, 26(7): 811-815
Abstract:
A synchronous fluorescence spectrometry combined with first order derivative treatment was deve-loped for the simultaneous determination of methylene blue(MB) and azure A(AA).The method is based upon the formation of ion-association complexes of AuCl4- with MB and AA,and the solvent extraction of two complexes by 1,2-dichloroethane in an aciditive medium.When [MB][AuCl4]3 and [AA][AuCl4]2 complexes were synchronously scanned at Δλ=20 nm and treated with first order derivative techniques in organic phase,the derivative-synchronous fluorescence peaks appeared at 683 nm for [MB][AuCl4]3 and at 608 nm for [AA][AuCl4]2,respectively.The fluorescence intensities were directly proportional to the concentrations of MB at 683 nm and AA at 608 nm within a certain range.So,a simple,sensitive method has been developed for the simultaneous determination of MB and AA.The detection limit(3σ) and linear range were 7.90×10-9 g/mL and 3.0×10-8~4.80×10-6 g/mL for MB,1.78×10-8 g/mL and 6.0×10-8~5.80×10-6 g/mL for AA,respectively.In this work,the spectral characteristics and compostion of ion-association complexes,the optimum conditions and the influences on the reaction system were investigated.The method can be applied to the simultaneous determination of AA and MB in urine samples and in Azure II with satisfactory results.
A synchronous fluorescence spectrometry combined with first order derivative treatment was deve-loped for the simultaneous determination of methylene blue(MB) and azure A(AA).The method is based upon the formation of ion-association complexes of AuCl4- with MB and AA,and the solvent extraction of two complexes by 1,2-dichloroethane in an aciditive medium.When [MB][AuCl4]3 and [AA][AuCl4]2 complexes were synchronously scanned at Δλ=20 nm and treated with first order derivative techniques in organic phase,the derivative-synchronous fluorescence peaks appeared at 683 nm for [MB][AuCl4]3 and at 608 nm for [AA][AuCl4]2,respectively.The fluorescence intensities were directly proportional to the concentrations of MB at 683 nm and AA at 608 nm within a certain range.So,a simple,sensitive method has been developed for the simultaneous determination of MB and AA.The detection limit(3σ) and linear range were 7.90×10-9 g/mL and 3.0×10-8~4.80×10-6 g/mL for MB,1.78×10-8 g/mL and 6.0×10-8~5.80×10-6 g/mL for AA,respectively.In this work,the spectral characteristics and compostion of ion-association complexes,the optimum conditions and the influences on the reaction system were investigated.The method can be applied to the simultaneous determination of AA and MB in urine samples and in Azure II with satisfactory results.
2009, 26(7): 816-821
Abstract:
Hexadecyltrimethylammonium bromide(CTAB) modified clay(CTAB-NaMM) electrode was made.The electrochemical behavior of paraquat(PQ) was studied by cyclic voltammetry and the process was controlled by diffusion.The important electrochemical parameters including the effective area of CTAB-NaMM-CMC/GCE Aeff=2.108 mm2,and the diffusion coefficient D=5.73×10-4 cm2/s was calculated.The correlation between the peak current and concentration was studied by square wave stripping voltammetry(SWSV).From the results we can find a good linearity between the peak current and concentration of PQ in a range of 9.660×10-7~3.865×10-4 mol/L,and its detect limitation was 3.297×10-7 mol/L.The content of PQ in real water was detected by means of SWSV with a spiked recovery rate of between 94.55% and 108.25% for ipa1.
Hexadecyltrimethylammonium bromide(CTAB) modified clay(CTAB-NaMM) electrode was made.The electrochemical behavior of paraquat(PQ) was studied by cyclic voltammetry and the process was controlled by diffusion.The important electrochemical parameters including the effective area of CTAB-NaMM-CMC/GCE Aeff=2.108 mm2,and the diffusion coefficient D=5.73×10-4 cm2/s was calculated.The correlation between the peak current and concentration was studied by square wave stripping voltammetry(SWSV).From the results we can find a good linearity between the peak current and concentration of PQ in a range of 9.660×10-7~3.865×10-4 mol/L,and its detect limitation was 3.297×10-7 mol/L.The content of PQ in real water was detected by means of SWSV with a spiked recovery rate of between 94.55% and 108.25% for ipa1.
2009, 26(7): 822-825
Abstract:
L-Phenylalanine modified electrode was prapared and used to detect uric acid(UA) in urine via cyclic voltammetry.In phosphate buffer solution(pH=5.6),UA displayed a sensitive oxidation peak at 0.43 V on L-phenylalanine modified electrode.The peak current was well proportional to the concentration of UA in a range of 2.0×10-6~3.0×10-4 mol/L with a detection limit of 1×10-6 mol/L.The relative standard deviation was estimated to be 3.0% from the parallel determinations of 1.0×10-5 mol/L uric acid in quintuplicate.The modified electrode is easy to prepare with good reproducibility and has been applied to the determination of UA in urine with satisfactory results.
L-Phenylalanine modified electrode was prapared and used to detect uric acid(UA) in urine via cyclic voltammetry.In phosphate buffer solution(pH=5.6),UA displayed a sensitive oxidation peak at 0.43 V on L-phenylalanine modified electrode.The peak current was well proportional to the concentration of UA in a range of 2.0×10-6~3.0×10-4 mol/L with a detection limit of 1×10-6 mol/L.The relative standard deviation was estimated to be 3.0% from the parallel determinations of 1.0×10-5 mol/L uric acid in quintuplicate.The modified electrode is easy to prepare with good reproducibility and has been applied to the determination of UA in urine with satisfactory results.
2009, 26(7): 826-830
Abstract:
Electrochemical behavior and kinetic parameters of vitamin B6(VB6) were investigated at poly-L-tryptophan modified glassy carbon electrode(PTRP/GCE) by cyclic voltammetry(CV),linear sweep voltammetry(LSV) and chronocoulometry(CC).Electrochemical results show that VB6 electrochemical behavior exhibits an irreversible oxidation at 1.085 V(vs.SCE) with one electron transfer and one proton.The peak currents are linearly related to the square root of scan rates in a scan rate range of 20～400 mV/s.The effective area of PTRP/GCE Aeff and the diffusion coefficient D are 0.29 cm2 and 1.961 2×10-4 cm2/s,respectively.In a HAc-NaAc buffer solution of pH=3.0,the oxidation peak current of VB6 versus its conce-ntration exhibits a good linear relationship in a concentration range of 1×10-4～5×10-6 mol/L with a correlation coefficient of 0.993 1 and a detection limit of 1×10-6 mol/L.The linear regression equation is ipa(μA) =7.740+408.813c(mmol/L) and the recovery is 100.15%.
Electrochemical behavior and kinetic parameters of vitamin B6(VB6) were investigated at poly-L-tryptophan modified glassy carbon electrode(PTRP/GCE) by cyclic voltammetry(CV),linear sweep voltammetry(LSV) and chronocoulometry(CC).Electrochemical results show that VB6 electrochemical behavior exhibits an irreversible oxidation at 1.085 V(vs.SCE) with one electron transfer and one proton.The peak currents are linearly related to the square root of scan rates in a scan rate range of 20～400 mV/s.The effective area of PTRP/GCE Aeff and the diffusion coefficient D are 0.29 cm2 and 1.961 2×10-4 cm2/s,respectively.In a HAc-NaAc buffer solution of pH=3.0,the oxidation peak current of VB6 versus its conce-ntration exhibits a good linear relationship in a concentration range of 1×10-4～5×10-6 mol/L with a correlation coefficient of 0.993 1 and a detection limit of 1×10-6 mol/L.The linear regression equation is ipa(μA) =7.740+408.813c(mmol/L) and the recovery is 100.15%.
2009, 26(7): 831-834
Abstract:
The electrocatalytic performance of Pd/TiC-C catalysts for the oxidation of formic acid was investigated.It was found that the electrocatalytic performance of Pd/TiC-C catalysts for the oxidation of formic acid in the direct formic acid fuel cell(DFAFC) is better than that of Pd/C catalyst.Furthermore,the electrocatalytic performance of Pd/TiC-C catalysts is related to the mass ratio of C and TiC.When the mass ratio of C and TiC is 2:1,the electrocatalytic activity and stability of Pd/TiC-C catalyst is the best.The peak potential of the oxidation of formic acid at Pd/TiC-C catalyst with a mass ratio of 2:1 is located at 0.164 V,which is 12 mV more negative than that at Pd/C catalyst electrode.The peak current density is 23.08×10-3 A/cm2,which is 42% larger than that at Pd/C catalyst electrode.
The electrocatalytic performance of Pd/TiC-C catalysts for the oxidation of formic acid was investigated.It was found that the electrocatalytic performance of Pd/TiC-C catalysts for the oxidation of formic acid in the direct formic acid fuel cell(DFAFC) is better than that of Pd/C catalyst.Furthermore,the electrocatalytic performance of Pd/TiC-C catalysts is related to the mass ratio of C and TiC.When the mass ratio of C and TiC is 2:1,the electrocatalytic activity and stability of Pd/TiC-C catalyst is the best.The peak potential of the oxidation of formic acid at Pd/TiC-C catalyst with a mass ratio of 2:1 is located at 0.164 V,which is 12 mV more negative than that at Pd/C catalyst electrode.The peak current density is 23.08×10-3 A/cm2,which is 42% larger than that at Pd/C catalyst electrode.
2009, 26(7): 835-839
Abstract:
This paper deals with the differences of physical properties and electrochemical performances of two Li4Ti5O12-C composites synthesized under different reaction atmospheres.The composites were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),BET,electric conductivity and electrochemical tests.Results show that the size,BET and electric conductivity of the sample sintered under N2 were all higher than those of sample sintered under air.The rate property of the sample sintered under N2 is better than that of the sample sintered under air.The initial specific capacity of the sample sintered under N2 is 166.8 mA·h/g at 0.1 C.Cycle efficiency of the two samples are similar after cycled 50 s at 1 C.
This paper deals with the differences of physical properties and electrochemical performances of two Li4Ti5O12-C composites synthesized under different reaction atmospheres.The composites were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),BET,electric conductivity and electrochemical tests.Results show that the size,BET and electric conductivity of the sample sintered under N2 were all higher than those of sample sintered under air.The rate property of the sample sintered under N2 is better than that of the sample sintered under air.The initial specific capacity of the sample sintered under N2 is 166.8 mA·h/g at 0.1 C.Cycle efficiency of the two samples are similar after cycled 50 s at 1 C.
2009, 26(7): 840-844
Abstract:
A novel inlaid super-thin microcrystalline cellulose modified carbon paste film electrode(ISM/CPE) was fabricated by direct inlaying microcrystalline cellulose modified carbon paste film on the surface of nichrome substrate.The characteristics of ISM/CPE were investigated by scanning electron microscopy(SEM) and cyclic voltammetry.The electrochemical behavior of the electrode was examined with ascorbic acid(AA) as an object.The oxidation peak potential(Epa) of AA was observed at 0.38 V,which was shifted by 0.05 V negatively compared to the Epa at the conventional carbon paste electrode.The oxidation peak current was linearly proportional to the concentration of AA in a range of 1.0×10-6～1.0×10-3 mol/L with a correlation coefficient of 0.999 3 and a detection limit(S/N=3) of 7.5×10-7 mol/L,showing that the electrochemical properties of the substrate electrode were changed after super-thin microcrystalline cellulose modified carbon paste film was inlaid and it could be applied to the determination of AA in real samples.
A novel inlaid super-thin microcrystalline cellulose modified carbon paste film electrode(ISM/CPE) was fabricated by direct inlaying microcrystalline cellulose modified carbon paste film on the surface of nichrome substrate.The characteristics of ISM/CPE were investigated by scanning electron microscopy(SEM) and cyclic voltammetry.The electrochemical behavior of the electrode was examined with ascorbic acid(AA) as an object.The oxidation peak potential(Epa) of AA was observed at 0.38 V,which was shifted by 0.05 V negatively compared to the Epa at the conventional carbon paste electrode.The oxidation peak current was linearly proportional to the concentration of AA in a range of 1.0×10-6～1.0×10-3 mol/L with a correlation coefficient of 0.999 3 and a detection limit(S/N=3) of 7.5×10-7 mol/L,showing that the electrochemical properties of the substrate electrode were changed after super-thin microcrystalline cellulose modified carbon paste film was inlaid and it could be applied to the determination of AA in real samples.
2009, 26(7): 845-847
Abstract:
6,7-Diacetoxylbaicalein was synthesized in a yield of 67.6% by direct acetylation of baicalin,the main active component of a traditional Chinese herb Scutellaria baicalensis Georgi,with acetic anhydride catalyzd using CH3COOK/Py under reflux.The monoacetylated derivative 6-acetoxyl baicalein or mono-O-methylated derivative 6-acetoxy-7-methoxylbaicalein was prepared in an excellent yield from 6,7-diacetoxylbaicalein via a high selective hydrolysis reaction in the presence of K2CO3/acetone-H2O or a methoxylation reaction at the C-7 position with Me2SO4,respectively.
6,7-Diacetoxylbaicalein was synthesized in a yield of 67.6% by direct acetylation of baicalin,the main active component of a traditional Chinese herb Scutellaria baicalensis Georgi,with acetic anhydride catalyzd using CH3COOK/Py under reflux.The monoacetylated derivative 6-acetoxyl baicalein or mono-O-methylated derivative 6-acetoxy-7-methoxylbaicalein was prepared in an excellent yield from 6,7-diacetoxylbaicalein via a high selective hydrolysis reaction in the presence of K2CO3/acetone-H2O or a methoxylation reaction at the C-7 position with Me2SO4,respectively.
2009, 26(7): 848-850
Abstract:
The thiacalixarene was synthesized from p-tert-butycalix[4]arene,following a series of reactions by decorating thiacrown ethers on the bottom edge and two aminos on the top edges.The target product could be used as the polymer monomer and the structure was characterized by 1H NMR,MS,IR,elemental analysis and mealting point measurement.
The thiacalixarene was synthesized from p-tert-butycalix[4]arene,following a series of reactions by decorating thiacrown ethers on the bottom edge and two aminos on the top edges.The target product could be used as the polymer monomer and the structure was characterized by 1H NMR,MS,IR,elemental analysis and mealting point measurement.
2009, 26(7): 851-853
Abstract:
The uncatalyzed epoxidation of cyclooctene with molecular oxygen as oxidant under solvent-free and no-inducement conditions has been studied.The effects of reaction conditions sush as temperature,time and pressure on the epoxidation of cyclooctene were investigated.The 44.5% of cyclooctene conversion and 64.4% of cyclooctane epoxide selectivity were obtained when the reaction was carried out at 140 ℃ and initial O2 pressure 0.60 MPa for 2.0 h.
The uncatalyzed epoxidation of cyclooctene with molecular oxygen as oxidant under solvent-free and no-inducement conditions has been studied.The effects of reaction conditions sush as temperature,time and pressure on the epoxidation of cyclooctene were investigated.The 44.5% of cyclooctene conversion and 64.4% of cyclooctane epoxide selectivity were obtained when the reaction was carried out at 140 ℃ and initial O2 pressure 0.60 MPa for 2.0 h.
2009, 26(7): 854-856
Abstract:
The effects of EuCl3,LaCl3,CeCl3 and PrCl3 as catalyst on the yields of capsinoids derivatives were studied.The results show that LaCl3 is the best catalyst among them.When the molar ratio of vanillyl alcohol,acyl chloride and LaCl3 was 1:1:0.005,the yields of vanillyl caprylate,vanillyl deaconate and vanillyl dilaurate would be up to 87%,85% and 71%,respectively.
The effects of EuCl3,LaCl3,CeCl3 and PrCl3 as catalyst on the yields of capsinoids derivatives were studied.The results show that LaCl3 is the best catalyst among them.When the molar ratio of vanillyl alcohol,acyl chloride and LaCl3 was 1:1:0.005,the yields of vanillyl caprylate,vanillyl deaconate and vanillyl dilaurate would be up to 87%,85% and 71%,respectively.
2009, 26(7): 857-859
Abstract:
In the presence of titanium(Ⅳ) ethoxide,chiral menthyl phenylglyoxylate was prepared via transesterification of ethyl phenylglyoxylate and the abundant natural chiral menthol,and the yield of the transesterification was 68%.In the auxiliaries of asymmetric factor,the menthyl R-2-hydroxy-2-phenyl-3-nitropropionate was synthesized by the Henry reaction with menthyl phenylglyoxylate and nitromethane,and the yield was 86%.Their structures were confirmed by IR,1H NMR,13C NMR spectroscopy and elemental analysis.The enantioselectivity was analyzed by HPLC,and the enantiomeric excess(e.e) was 52.8%.
In the presence of titanium(Ⅳ) ethoxide,chiral menthyl phenylglyoxylate was prepared via transesterification of ethyl phenylglyoxylate and the abundant natural chiral menthol,and the yield of the transesterification was 68%.In the auxiliaries of asymmetric factor,the menthyl R-2-hydroxy-2-phenyl-3-nitropropionate was synthesized by the Henry reaction with menthyl phenylglyoxylate and nitromethane,and the yield was 86%.Their structures were confirmed by IR,1H NMR,13C NMR spectroscopy and elemental analysis.The enantioselectivity was analyzed by HPLC,and the enantiomeric excess(e.e) was 52.8%.
2009, 26(7): 860-862
Abstract:
This paper presents an experimental investigation on the crystallization thermodynamics of coba-lamine by means of laser.The influences of temperature and different solvents on the solubility and supersolubility are studied.The metastable zone is also measured.It shows that the metastable zone width becomes wider with decreasing the proportion of acetone.The influences of four typical ionic impurities(Na+,Mg2+,Ca2+ and Fe3+) on cobalamine crystallization are studied.Some of crystallization products become fragmentation and agglomeration with ionic impurities existence.The surface configuration has been characterized by SEM.As a result,it shows that Fe3+ and Mg2+ have more significant effects than Na+ and Ca2+.
This paper presents an experimental investigation on the crystallization thermodynamics of coba-lamine by means of laser.The influences of temperature and different solvents on the solubility and supersolubility are studied.The metastable zone is also measured.It shows that the metastable zone width becomes wider with decreasing the proportion of acetone.The influences of four typical ionic impurities(Na+,Mg2+,Ca2+ and Fe3+) on cobalamine crystallization are studied.Some of crystallization products become fragmentation and agglomeration with ionic impurities existence.The surface configuration has been characterized by SEM.As a result,it shows that Fe3+ and Mg2+ have more significant effects than Na+ and Ca2+.
2009, 26(7): 863-865
Abstract:
Microwave-assisted synthesis of a novel cyclometalated iridium(Ⅲ) quinoxaline complex with the formula Ir(DPQ)3(DPQ=2,3-diphenylquinoxaline) was performed via the reaction of DPQ and iridium trichloride hydrate.The complex was characterized by elemental analysis,1H NMR and mass spectrometry.The complex shows strong 1MLCT(singlet metal to ligand charge-transfer) absorption at 387 and 3MLCT(triplet metal to ligand charge-transfer) absorption at 458 nm,respectively.The complex also shows strong photoluminescence at 634 nm at room temperature.These results suggest that the complex is a promising phosphorescent material.
Microwave-assisted synthesis of a novel cyclometalated iridium(Ⅲ) quinoxaline complex with the formula Ir(DPQ)3(DPQ=2,3-diphenylquinoxaline) was performed via the reaction of DPQ and iridium trichloride hydrate.The complex was characterized by elemental analysis,1H NMR and mass spectrometry.The complex shows strong 1MLCT(singlet metal to ligand charge-transfer) absorption at 387 and 3MLCT(triplet metal to ligand charge-transfer) absorption at 458 nm,respectively.The complex also shows strong photoluminescence at 634 nm at room temperature.These results suggest that the complex is a promising phosphorescent material.
2009, 26(7): 866-868
Abstract:
AMPS(2-acrylamido-2-methylpropanesulfonicacid)/MMA(methyl methacrylate) copolymer microspheres were prepared without initiator or emulsifier by ultrasonic irradiation emulsifier-free emulsion polymerization.The samples were characterized and tested by FTIR,TGA-DSC,TEM and Zeta-sizer,and the reaction mechanism of the copolymerization was studied as well.The results show that the monomer conversion was 83% in 75 minutes at a power output of 200 W and 45 ℃.The microspheres possess a good dispersity,a uniform size with a diameter of 0.77 μm and a Tg of 120 ℃.
AMPS(2-acrylamido-2-methylpropanesulfonicacid)/MMA(methyl methacrylate) copolymer microspheres were prepared without initiator or emulsifier by ultrasonic irradiation emulsifier-free emulsion polymerization.The samples were characterized and tested by FTIR,TGA-DSC,TEM and Zeta-sizer,and the reaction mechanism of the copolymerization was studied as well.The results show that the monomer conversion was 83% in 75 minutes at a power output of 200 W and 45 ℃.The microspheres possess a good dispersity,a uniform size with a diameter of 0.77 μm and a Tg of 120 ℃.
2009, 26(7): 869-871
Abstract:
A post chemiluminescence(PCL) reaction was observed when isoniazid was injected into the reaction mixture of potassium ferricyanide-calcein chemiluminescence(CL) reaction system.The experimental conditions of the CL reactions were optimized.A new chemiluminesence method coupled with flow injection technique for the determination of isoniazid was developed.The detection limit was 6×10-8 g/mL,and the relative standard deviation was 1.8%(2.0×10-6 g/mL isoniazid,n=11),and the liner range was 2.0×10-7~1.0×10-5 g/mL.The method has been successfully applied to the determination of isoniazid in the isoniazid tablets and the results were consistent with that determined by means of the method in the Chinese pharmacopoeia.
A post chemiluminescence(PCL) reaction was observed when isoniazid was injected into the reaction mixture of potassium ferricyanide-calcein chemiluminescence(CL) reaction system.The experimental conditions of the CL reactions were optimized.A new chemiluminesence method coupled with flow injection technique for the determination of isoniazid was developed.The detection limit was 6×10-8 g/mL,and the relative standard deviation was 1.8%(2.0×10-6 g/mL isoniazid,n=11),and the liner range was 2.0×10-7~1.0×10-5 g/mL.The method has been successfully applied to the determination of isoniazid in the isoniazid tablets and the results were consistent with that determined by means of the method in the Chinese pharmacopoeia.
2009, 26(7): 872-874
Abstract:
Scoparone was separated and concentrated from artemisia capillaris thunb by solvent sublation and determined with high-performance liquid chromatography(HPLC).The experimental conditions such as solution pH,type of solvent,nitrogen flow rate and sublation time were optimized for efficient sublation.The recoveries ranged from 92.31% to 99.97% under the optimal conditions;the RSD value for 5 replicate measurements of the sample was 3.20%.
Scoparone was separated and concentrated from artemisia capillaris thunb by solvent sublation and determined with high-performance liquid chromatography(HPLC).The experimental conditions such as solution pH,type of solvent,nitrogen flow rate and sublation time were optimized for efficient sublation.The recoveries ranged from 92.31% to 99.97% under the optimal conditions;the RSD value for 5 replicate measurements of the sample was 3.20%.
2009, 26(7): 875-877
Abstract:
A multi-wall carbon nanotubes modified acetylene black electrode was prepared and the voltamme-tric characteristics of iodine ions on the modified electrode was studied.The effects of the type and acidity of electrolytes on the oxidation peak current of iodine ions were also studied to acquire optimum conditions.In 0.4 mol/L KH2PO4 solution(pH=4.0),when scanning linearly from 200 mV to 1 200 mV at a scan rate of 200 mV/s,a sensitive oxidation peak appeared at 570 mV(vs.SCE).The peak current of the modified electrode raised around three fold than that of the unmodified electrode.By means of the second derivative linear sweep technique,good linearity was obtained between the oxidation peak current and the concentration of iodine ions in a range of 2.0×10-6～1.0×10-3 mol/L,and the detection limit reached 8.0×10-7 mol/L.This method was successfully applied to the determination of iodine in edible salt.The relative standard deviation was between 1.2%~1.6%,and the relative error was between 97.4%~103%.
A multi-wall carbon nanotubes modified acetylene black electrode was prepared and the voltamme-tric characteristics of iodine ions on the modified electrode was studied.The effects of the type and acidity of electrolytes on the oxidation peak current of iodine ions were also studied to acquire optimum conditions.In 0.4 mol/L KH2PO4 solution(pH=4.0),when scanning linearly from 200 mV to 1 200 mV at a scan rate of 200 mV/s,a sensitive oxidation peak appeared at 570 mV(vs.SCE).The peak current of the modified electrode raised around three fold than that of the unmodified electrode.By means of the second derivative linear sweep technique,good linearity was obtained between the oxidation peak current and the concentration of iodine ions in a range of 2.0×10-6～1.0×10-3 mol/L,and the detection limit reached 8.0×10-7 mol/L.This method was successfully applied to the determination of iodine in edible salt.The relative standard deviation was between 1.2%~1.6%,and the relative error was between 97.4%~103%.
2009, 26(7): 878-880
Abstract:
Two new polyaluminum compounds,AlCl3·4Al(OH)3·7.5H2O and 2AlCl3·7Al(OH)3·18H2O,were prepared from aluminum powder,aluminum chloride and distilled water by adjusting the reaction temperature,raw material ratio and degree of basification,and evaporation and crystallization.The polyaluminum chlorides were characterized by XRD,chemical analysis and IR.We discovered that the change of reaction with the change of temperature was a reversible process.The optimal formation temperature for AlCl3·4Al(OH)3·7.5H2O and 2AlCl3·7Al(OH)3·18H2O was 75 ℃.The products crystallized very well,and their purities were 99.57% and 88.68% respeatively.
Two new polyaluminum compounds,AlCl3·4Al(OH)3·7.5H2O and 2AlCl3·7Al(OH)3·18H2O,were prepared from aluminum powder,aluminum chloride and distilled water by adjusting the reaction temperature,raw material ratio and degree of basification,and evaporation and crystallization.The polyaluminum chlorides were characterized by XRD,chemical analysis and IR.We discovered that the change of reaction with the change of temperature was a reversible process.The optimal formation temperature for AlCl3·4Al(OH)3·7.5H2O and 2AlCl3·7Al(OH)3·18H2O was 75 ℃.The products crystallized very well,and their purities were 99.57% and 88.68% respeatively.
