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2009 Volume 26 Issue 6
2009, 26(6): 625-628
Abstract:
The clean and effective oxidant,hydrogen peroxide,was used to degrade alginate in order to prepare its low molecular products,and the effects of pH,temperature,amount of H2O2 and metal ions on the degradation were investigated.The degradation rate increased with the decrease of solution pH,and the increases of reaction temperature and oxidant dosage.Low molecular alginate could be obtained effectively with pH of 5.3,temperature of 50 ℃ and H2O2 of 0.5% for 2 h reaction.The reaction could be also significantly accelerated by 4 mg/L Cu2+ or Fe2+.GPC analysis showed that the average molecular mass of alginate was decreased and the molecular mass distribution was broadened.It can be inferred from FTIR that the degradation was caused by OH radicals produced by hydrogen peroxide,which resulted in the breakage of the glycosidic C(1)—O—C(4) bond.
The clean and effective oxidant,hydrogen peroxide,was used to degrade alginate in order to prepare its low molecular products,and the effects of pH,temperature,amount of H2O2 and metal ions on the degradation were investigated.The degradation rate increased with the decrease of solution pH,and the increases of reaction temperature and oxidant dosage.Low molecular alginate could be obtained effectively with pH of 5.3,temperature of 50 ℃ and H2O2 of 0.5% for 2 h reaction.The reaction could be also significantly accelerated by 4 mg/L Cu2+ or Fe2+.GPC analysis showed that the average molecular mass of alginate was decreased and the molecular mass distribution was broadened.It can be inferred from FTIR that the degradation was caused by OH radicals produced by hydrogen peroxide,which resulted in the breakage of the glycosidic C(1)—O—C(4) bond.
2009, 26(6): 629-632
Abstract:
Low-molecular-mass CSM was prepared by degrading CSM,and it was used to modify silicon nitride nanoparticles(Si3N4).The structure and surface properties of modified nano-Si3N4 were systematically characterized by FTIR,TEM,TGA,dispersion stabilization and contact angle measurement.The result shows that chemical modification is primary,the chemical and physical usage efficiencies of the macromolecular coupling are 54% and 29% respectively.The surface free energy of modified nano-Si3N4 has been decreased from 142.6 J/M2 to 66.89 J/M2,resulting in a good dispersibility of nano-Si3N4 in chloroform.
Low-molecular-mass CSM was prepared by degrading CSM,and it was used to modify silicon nitride nanoparticles(Si3N4).The structure and surface properties of modified nano-Si3N4 were systematically characterized by FTIR,TEM,TGA,dispersion stabilization and contact angle measurement.The result shows that chemical modification is primary,the chemical and physical usage efficiencies of the macromolecular coupling are 54% and 29% respectively.The surface free energy of modified nano-Si3N4 has been decreased from 142.6 J/M2 to 66.89 J/M2,resulting in a good dispersibility of nano-Si3N4 in chloroform.
2009, 26(6): 633-636
Abstract:
We reported the biomimetic synthesis of hybrid silica nanoparticles mediated with linear cationic poly(acrylamide-co-dimethylaminoethylacrylate-methyl chloride)[poly(AM-co-DMC)].The hybrid silica nanoparticles were simply synthesized by stirring a mixture of the aqueous solution of poly(AM-co-DMC) with tetramethoxysilane(TMOS) at ambient temperature for typically 30 min.The hybrid nanoparticles were well characterized with FT-IR,TEM,TEM-EDX and TGA.The representative hybrid nanoparticles were roughly spherical,with an average diameter of around 15 nm and a good monodispersity.EDX analysis,FT-IR and TGA analyses have confirmed that the hybrid particle is composed of polyamines and inorganic silica.In addition,we also found that the formation of hybrid nanoparitlces depended on the mineralization reaction time for silica deposition.
We reported the biomimetic synthesis of hybrid silica nanoparticles mediated with linear cationic poly(acrylamide-co-dimethylaminoethylacrylate-methyl chloride)[poly(AM-co-DMC)].The hybrid silica nanoparticles were simply synthesized by stirring a mixture of the aqueous solution of poly(AM-co-DMC) with tetramethoxysilane(TMOS) at ambient temperature for typically 30 min.The hybrid nanoparticles were well characterized with FT-IR,TEM,TEM-EDX and TGA.The representative hybrid nanoparticles were roughly spherical,with an average diameter of around 15 nm and a good monodispersity.EDX analysis,FT-IR and TGA analyses have confirmed that the hybrid particle is composed of polyamines and inorganic silica.In addition,we also found that the formation of hybrid nanoparitlces depended on the mineralization reaction time for silica deposition.
2009, 26(6): 637-641
Abstract:
Carbonic anhydrase(CA) was immobilized onto the surface of hollow fiber membrane of polymethyl pentene(PMP) without any active functional groups via sulfosuccinimidyl [perfluoroazidobenzamido] ethyl-1,3-dithiopropionate(SFAD),a photoactivatable heterobifunctional crosslinker.Using p-nitrophenyl acetate(p-NPA) as a substrate,the activity,concentration,storage stability and re-usability of immobilized CA were studied by ultraviolet spectrophotometry.The preliminary data showed that CA could be successfully immobilized onto PMP surface;covalently immobilized CA(CACI) had catalysis activity.Its concentration on PMP surface increased with the increase of the SFAD concentration,and reached a maximum of 0.414 U/m2,which was 87.3% of the theoretical concentration of CA on PMP surface in monolayer,and the reusability was much better than physically adsorbed CA(CAPA): the activity of CAPA on PMP surface was 0 after washing once,but CACI retained around 59% of its activity after washing 9 times;CACI showed higher storage stability compared to free CA in solution at 37 ℃: the soluble enzyme lost about 90% activity,but CACI lost only 60% activity in 16 days.
Carbonic anhydrase(CA) was immobilized onto the surface of hollow fiber membrane of polymethyl pentene(PMP) without any active functional groups via sulfosuccinimidyl [perfluoroazidobenzamido] ethyl-1,3-dithiopropionate(SFAD),a photoactivatable heterobifunctional crosslinker.Using p-nitrophenyl acetate(p-NPA) as a substrate,the activity,concentration,storage stability and re-usability of immobilized CA were studied by ultraviolet spectrophotometry.The preliminary data showed that CA could be successfully immobilized onto PMP surface;covalently immobilized CA(CACI) had catalysis activity.Its concentration on PMP surface increased with the increase of the SFAD concentration,and reached a maximum of 0.414 U/m2,which was 87.3% of the theoretical concentration of CA on PMP surface in monolayer,and the reusability was much better than physically adsorbed CA(CAPA): the activity of CAPA on PMP surface was 0 after washing once,but CACI retained around 59% of its activity after washing 9 times;CACI showed higher storage stability compared to free CA in solution at 37 ℃: the soluble enzyme lost about 90% activity,but CACI lost only 60% activity in 16 days.
2009, 26(6): 642-645
Abstract:
Block copolymer surfactants of TETA-DGEPG-EPON828,TETA-DGEPG-EPON834,TETA-DGEPG-EPON1001 were synthesized and characterized.The hydrophile-lipophile balance(HLB) values were 16.6,15.8 and 13.0 respectively obtained by calculation.The cloud points were 91.0 ℃,89.0 ℃ and 81.0 ℃,respectively.The surface tensions of the obtained surfactants in aqueous solution at 25 ℃ were investigated.The results show that they could reduce the surface tension in aqueous solution from 74 mN/m to 36.4~39.4 mN/m.From the study on the physicochemical properties,it shows that TETA-DGEPG-EPON834 had a good water-solubility and favorable surface performance.TETA-DGEPG-EPON834 can be used as phase inversion emulsifiers to prepare stable aqueous amine dispersion of EPON828-TETA adduct terminated with CARDURA E10,and the average particle size is well below 1 μm.
Block copolymer surfactants of TETA-DGEPG-EPON828,TETA-DGEPG-EPON834,TETA-DGEPG-EPON1001 were synthesized and characterized.The hydrophile-lipophile balance(HLB) values were 16.6,15.8 and 13.0 respectively obtained by calculation.The cloud points were 91.0 ℃,89.0 ℃ and 81.0 ℃,respectively.The surface tensions of the obtained surfactants in aqueous solution at 25 ℃ were investigated.The results show that they could reduce the surface tension in aqueous solution from 74 mN/m to 36.4~39.4 mN/m.From the study on the physicochemical properties,it shows that TETA-DGEPG-EPON834 had a good water-solubility and favorable surface performance.TETA-DGEPG-EPON834 can be used as phase inversion emulsifiers to prepare stable aqueous amine dispersion of EPON828-TETA adduct terminated with CARDURA E10,and the average particle size is well below 1 μm.
2009, 26(6): 646-650
Abstract:
New europium complexes(C8H15O2)x(C12H23O2)yEu,which is soluble in MMA monomer,were synthesized with caprytlic acid(C8H15O2) and lauric acid(C12H23O2) as the first ligand by saponification method.Photoluminescent PMMA containing rare earth complexes AxByEu/PMMA(A=—C8H15O2,B=—C12H23O2,x,y was their mol ratio) were prepared by bulk polymerization.The effects of different second ligands(carbazole,dmbp,phen,HTTA) on the flourescent properties of the polymers were studied.Then AxByEu/HTTA/PMMA was prepared with ligand HTTA.The structures and fluorescence properties of the complexes and polymers containing europium were investigated by IR,UV and Fluorescence spectra.Results indicate that the polymers obtained emit strong characteristic luminescence of Eu3+ ions.Notably even if the mass fraction of HTTA was 0.02%,it could enhance the characteristic red luminescence of(C8H15O2)3Eu/HTTA/PMMA greatly,while the transparency of the polymer was not affected.
New europium complexes(C8H15O2)x(C12H23O2)yEu,which is soluble in MMA monomer,were synthesized with caprytlic acid(C8H15O2) and lauric acid(C12H23O2) as the first ligand by saponification method.Photoluminescent PMMA containing rare earth complexes AxByEu/PMMA(A=—C8H15O2,B=—C12H23O2,x,y was their mol ratio) were prepared by bulk polymerization.The effects of different second ligands(carbazole,dmbp,phen,HTTA) on the flourescent properties of the polymers were studied.Then AxByEu/HTTA/PMMA was prepared with ligand HTTA.The structures and fluorescence properties of the complexes and polymers containing europium were investigated by IR,UV and Fluorescence spectra.Results indicate that the polymers obtained emit strong characteristic luminescence of Eu3+ ions.Notably even if the mass fraction of HTTA was 0.02%,it could enhance the characteristic red luminescence of(C8H15O2)3Eu/HTTA/PMMA greatly,while the transparency of the polymer was not affected.
2009, 26(6): 651-656
Abstract:
Two mild,efficient and practical methods to synthesize O-chloro-benzoquinonyl C-glycopyranosides are reported.One is that,using NH4NO3 as a catalyst,aryl C-glycosides 1a and 1b were chlorinated by N-chlorosuccinimide to afford O-chlorinated compounds 2a and 2b in high regioselectivity.The corresponding benzoquinonyl C-glycosides 3a and 3b were obtained after oxidization with cerium ammonium nitrate(CAN) in an overall yield of 88% and 84%,respectively.The other is that,under the catalysis of BF3·Et2O,O-chloro-hydroquinonyl C-glycosides 5a and 5b can also be obtained through addition reaction and hydrolyzation involving benzoquinonyl C-glycosides and Me3SiCl in an overall yield of 82% and 76%,respectively.Additionally,corresponding hydroquinone and benzoquinone compounds can be transformed to each other through oxidation and reduction reactions.
Two mild,efficient and practical methods to synthesize O-chloro-benzoquinonyl C-glycopyranosides are reported.One is that,using NH4NO3 as a catalyst,aryl C-glycosides 1a and 1b were chlorinated by N-chlorosuccinimide to afford O-chlorinated compounds 2a and 2b in high regioselectivity.The corresponding benzoquinonyl C-glycosides 3a and 3b were obtained after oxidization with cerium ammonium nitrate(CAN) in an overall yield of 88% and 84%,respectively.The other is that,under the catalysis of BF3·Et2O,O-chloro-hydroquinonyl C-glycosides 5a and 5b can also be obtained through addition reaction and hydrolyzation involving benzoquinonyl C-glycosides and Me3SiCl in an overall yield of 82% and 76%,respectively.Additionally,corresponding hydroquinone and benzoquinone compounds can be transformed to each other through oxidation and reduction reactions.
2009, 26(6): 657-661
Abstract:
A new carbazole derivative,9-isooctyl-3,6-carbazole dicrylic acid,was synthesized and characte-rized by 1H NMR,13C NMR,IR and MS.UV,one-photon excited fluorescence spectra and solid fluorescence of the intermediate and title product in different polar solvents were investigated.The results show that the target product had good UV absorption characteristic and single-photon fluorescence effect at 300~500 nm with increasing polarity of the solvent.With the ethanol solution of Rhodamine B as a reference,we calculated the quantum yields of the target product in different solvents to be more than 0.19.So the compound could be a potential luminescent material.
A new carbazole derivative,9-isooctyl-3,6-carbazole dicrylic acid,was synthesized and characte-rized by 1H NMR,13C NMR,IR and MS.UV,one-photon excited fluorescence spectra and solid fluorescence of the intermediate and title product in different polar solvents were investigated.The results show that the target product had good UV absorption characteristic and single-photon fluorescence effect at 300~500 nm with increasing polarity of the solvent.With the ethanol solution of Rhodamine B as a reference,we calculated the quantum yields of the target product in different solvents to be more than 0.19.So the compound could be a potential luminescent material.
2009, 26(6): 662-666
Abstract:
Organotin compound {[(o-MeC6H4CH2)2Sn(O)]2(o-MeC6H4CH2NHO)}2 was synthesized by the reaction of di(o-methylbenzyl)tin dichloride with N-(o-methylbenzyl)hydroxylamine.Its structure was determined by X-ray single crystal diffraction.Crystallorgaphic for the compound: Triclinic,P-1,a=1.060 4(5) nm,b=1.307 8(7) nm,c=1.374 2(47) nm,α=105.174(12)°,β=90.229(7)°,γ=101.028(6)°,Z=1,V=1.802 5(15) nm3,Dc=1.522 Mg/m3,μ(MoKα)=1.423 mm-1,F(000)=834,R1=0.045 5,wR2=0.101 7.In the compound,the tin ions show five-coordination and exhibit distorted trigonal bipyramidal geometries.The complex has a ladder-like structure,which is composed of three Sn2O2 planes.The brief investigation shows that this tin compound has antitumour activity in vitro against WiDr and MCF-7 tumour cells.
Organotin compound {[(o-MeC6H4CH2)2Sn(O)]2(o-MeC6H4CH2NHO)}2 was synthesized by the reaction of di(o-methylbenzyl)tin dichloride with N-(o-methylbenzyl)hydroxylamine.Its structure was determined by X-ray single crystal diffraction.Crystallorgaphic for the compound: Triclinic,P-1,a=1.060 4(5) nm,b=1.307 8(7) nm,c=1.374 2(47) nm,α=105.174(12)°,β=90.229(7)°,γ=101.028(6)°,Z=1,V=1.802 5(15) nm3,Dc=1.522 Mg/m3,μ(MoKα)=1.423 mm-1,F(000)=834,R1=0.045 5,wR2=0.101 7.In the compound,the tin ions show five-coordination and exhibit distorted trigonal bipyramidal geometries.The complex has a ladder-like structure,which is composed of three Sn2O2 planes.The brief investigation shows that this tin compound has antitumour activity in vitro against WiDr and MCF-7 tumour cells.
2009, 26(6): 667-670
Abstract:
1-(1,3-Dithian-2-ylidene)propan-2-one(1f),an odorless and stable white crystal at room tempe-rature,was prepared readily in a yield of 86% via decarbonylation of 3-(1,3-dithian-2-ylidene)-pentane-2,4-dione(1b) under acidic condition.Thioacetalization reactions of the odorless 1f as an efficient 1,3-propandithiol equivalent with selected aldehydes and ketones were carried out at room temperature or under reflux in the presence of MeCOCl in MeOH,and 1,3-dithiane derivatives were obtained in high yields(86%~99%).Compared with reported 2-[2-chloro-1-(1-chlorovinyl)allylidene]-1,3-dithiane(1a),3-(1,3)-dithian-2-ylidenepentane-2,4-dione(1b),methyl 2-(1,3-dithian-2-ylidene)-3-oxobutanoate(1c),2-(1,3)dithian-2-ylidene-3-oxo-butanamide(1d) and 2-(1,3-dithian-2-ylidene)-3-oxobutanoic acid(1e),compound 1f has better activity as 1,3-propandithiol equivalent in thioacetalization reaction.
1-(1,3-Dithian-2-ylidene)propan-2-one(1f),an odorless and stable white crystal at room tempe-rature,was prepared readily in a yield of 86% via decarbonylation of 3-(1,3-dithian-2-ylidene)-pentane-2,4-dione(1b) under acidic condition.Thioacetalization reactions of the odorless 1f as an efficient 1,3-propandithiol equivalent with selected aldehydes and ketones were carried out at room temperature or under reflux in the presence of MeCOCl in MeOH,and 1,3-dithiane derivatives were obtained in high yields(86%~99%).Compared with reported 2-[2-chloro-1-(1-chlorovinyl)allylidene]-1,3-dithiane(1a),3-(1,3)-dithian-2-ylidenepentane-2,4-dione(1b),methyl 2-(1,3-dithian-2-ylidene)-3-oxobutanoate(1c),2-(1,3)dithian-2-ylidene-3-oxo-butanamide(1d) and 2-(1,3-dithian-2-ylidene)-3-oxobutanoic acid(1e),compound 1f has better activity as 1,3-propandithiol equivalent in thioacetalization reaction.
2009, 26(6): 671-675
Abstract:
A novel 1,4,7-triazacyclodecane and its 4 derivatives were synthesized.These compounds were characterized by elemental analysis,IR,1H NMR and MS techniques.The biological activities of these compounds were investigated against human cancer cells Hela and HCT26.The results showed that all the compounds possess,to some extent,antitumor activities which change in dose dependent manner.After treatment with compound 4,the degeneration and necrosis of HCT26 cells occurred,showing that compound 4 has significant apoptotic effect on HCT26 cells.
A novel 1,4,7-triazacyclodecane and its 4 derivatives were synthesized.These compounds were characterized by elemental analysis,IR,1H NMR and MS techniques.The biological activities of these compounds were investigated against human cancer cells Hela and HCT26.The results showed that all the compounds possess,to some extent,antitumor activities which change in dose dependent manner.After treatment with compound 4,the degeneration and necrosis of HCT26 cells occurred,showing that compound 4 has significant apoptotic effect on HCT26 cells.
2009, 26(6): 676-680
Abstract:
Chlorobenzene nitration was carried out with supported heteropoly acids as catalysts and N2O5 as nitrating agent.Many factors were investigated,such as kinds of heteropoly acids and carriers,loading of heteropoly acid,number of catalyst used,and so on.Results showed the nitration of chlorobenzene with N2O5 is an acid catalyzed reaction,and the supported heteropoly acids can highly enhance the nitration ability of N2O5;the catalyst can be directly reused after recycle,and its activity was not obviously decreased.Under the optimum conditions,the yield of the nitration was 26%,and the para-selectivity was up to 68.8%,which indicates that N2O5 is a prospective nitration agent,and it can replace the concentrated mineral acid as the catalyst which is one of the most environmentally harmful processes,and meets the requirement of green environmental protection.
Chlorobenzene nitration was carried out with supported heteropoly acids as catalysts and N2O5 as nitrating agent.Many factors were investigated,such as kinds of heteropoly acids and carriers,loading of heteropoly acid,number of catalyst used,and so on.Results showed the nitration of chlorobenzene with N2O5 is an acid catalyzed reaction,and the supported heteropoly acids can highly enhance the nitration ability of N2O5;the catalyst can be directly reused after recycle,and its activity was not obviously decreased.Under the optimum conditions,the yield of the nitration was 26%,and the para-selectivity was up to 68.8%,which indicates that N2O5 is a prospective nitration agent,and it can replace the concentrated mineral acid as the catalyst which is one of the most environmentally harmful processes,and meets the requirement of green environmental protection.
2009, 26(6): 681-685
Abstract:
A convenient synthetic method for the preparation of 3-carboxy-6,8-dichloro-7-hydroxy coumarin(DClC) and 3-carboxy-6-chloro-7-hydroxy coumarin(MClC) is provided,wherein DClC has not been reported in literature.The structures were confirmed by NMR,IR and MS spectra.At the same time,the effects of polarity of solvent,pH and surfactants on fluorescent and ultraviolet properties of the two coumarins were studied.The result indicates that the fluorescent intensity increased significantly with a pH=10.
A convenient synthetic method for the preparation of 3-carboxy-6,8-dichloro-7-hydroxy coumarin(DClC) and 3-carboxy-6-chloro-7-hydroxy coumarin(MClC) is provided,wherein DClC has not been reported in literature.The structures were confirmed by NMR,IR and MS spectra.At the same time,the effects of polarity of solvent,pH and surfactants on fluorescent and ultraviolet properties of the two coumarins were studied.The result indicates that the fluorescent intensity increased significantly with a pH=10.
2009, 26(6): 686-691
Abstract:
Two compounds,[Cu(im)4SO4]n(1) and [Cu(bpy)(H2O)2SO4]n(2)(im=imidazole,bpy=2,2'-bipyridine),were synthesized in ethanol/DMF systems with HNO3 in 67% and 82% yields,respectively.The relation between the crystal structure and acidity of the reaction system were investigated.As 0.35~0.6 mmol or 1.2~1.45 mmol HNO3 was added to the reaction system pure compound 1 or 2,respectively,was obtained.And they were further characterized by elemental analysis,IR,UV-Vis reflection spectra,inductively coupled plasma(ICP),TGA,X-ray powder diffraction and X-ray crystallography diffraction.The crystal structure analyses revealed that they all belong to the monoclinic system with space group C2/C,possessing chalcanthite-like configuration.Compound 1 exhibits a 1D zigzag chain structure,while 2 exhibits 1D linear chain,which is resulted from different ligands.UV-Vis reflection spectra of the two compounds indicated that the absorption bands in visible region are from the d-d transitions of copper(Ⅱ) ions and the absorption bands in ultraviolet region correspond to ligand→copper(Ⅱ) charge transfer and π→π* transition for compounds 1 and 2,respectively.
Two compounds,[Cu(im)4SO4]n(1) and [Cu(bpy)(H2O)2SO4]n(2)(im=imidazole,bpy=2,2'-bipyridine),were synthesized in ethanol/DMF systems with HNO3 in 67% and 82% yields,respectively.The relation between the crystal structure and acidity of the reaction system were investigated.As 0.35~0.6 mmol or 1.2~1.45 mmol HNO3 was added to the reaction system pure compound 1 or 2,respectively,was obtained.And they were further characterized by elemental analysis,IR,UV-Vis reflection spectra,inductively coupled plasma(ICP),TGA,X-ray powder diffraction and X-ray crystallography diffraction.The crystal structure analyses revealed that they all belong to the monoclinic system with space group C2/C,possessing chalcanthite-like configuration.Compound 1 exhibits a 1D zigzag chain structure,while 2 exhibits 1D linear chain,which is resulted from different ligands.UV-Vis reflection spectra of the two compounds indicated that the absorption bands in visible region are from the d-d transitions of copper(Ⅱ) ions and the absorption bands in ultraviolet region correspond to ligand→copper(Ⅱ) charge transfer and π→π* transition for compounds 1 and 2,respectively.
2009, 26(6): 692-696
Abstract:
In a solution containing 8 g/L sodium hexametaphosphate and 5 g/L sodium silicate,the influences of current density,duty cycle,sample dimension and solution temperature on the growing rate of MAO coatings on 6061 aluminum alloy were investigated.The results indicate that under high current density and voltage on sample surface,the growing rate of the coating increases linearly at a rate of 1.425 0×10-9 m3/(min·A) with the increasing of current density due the ability of high voltage to break down the MAO coatings that are continuously oxidized.Duty cycle has no impact on the growing rate of the coating,and the growing rates of different duty cycles are approximately 0.50 μm/min,but the voltage rises slightly with decreasing duty cycle.Growing rates of different dimension samples are 0.31 μm/min,while voltage increases with the increase of the sample size.The rising of solution temperature enhances the dissociation degree of HSiO3- and H2PO32-,improving the conductions of solution and ion diffusivity,which increases the growing rate of coating,and the growing rates under 10 ℃,20 ℃and 30 ℃ are 0.35 μm/min,0.38 μm/min,0.41 μm/min,respectively.
In a solution containing 8 g/L sodium hexametaphosphate and 5 g/L sodium silicate,the influences of current density,duty cycle,sample dimension and solution temperature on the growing rate of MAO coatings on 6061 aluminum alloy were investigated.The results indicate that under high current density and voltage on sample surface,the growing rate of the coating increases linearly at a rate of 1.425 0×10-9 m3/(min·A) with the increasing of current density due the ability of high voltage to break down the MAO coatings that are continuously oxidized.Duty cycle has no impact on the growing rate of the coating,and the growing rates of different duty cycles are approximately 0.50 μm/min,but the voltage rises slightly with decreasing duty cycle.Growing rates of different dimension samples are 0.31 μm/min,while voltage increases with the increase of the sample size.The rising of solution temperature enhances the dissociation degree of HSiO3- and H2PO32-,improving the conductions of solution and ion diffusivity,which increases the growing rate of coating,and the growing rates under 10 ℃,20 ℃and 30 ℃ are 0.35 μm/min,0.38 μm/min,0.41 μm/min,respectively.
2009, 26(6): 697-701
Abstract:
Flaky hydrated strontium borate(SrB6O10·5H2O) was synthesized by liquid-phase precipitation method with strontium chloride and ammonium hydrogen borate as the raw materials.The product was characterized by XRD,FT-IR and SEM.The thermal decomposition Kinetics of SrB6O10·5H2O was studied by thermogravimetric analysis.The data of TG-DTA was analyzed by isoconversional non-linear and Coats-Redfern methods.The four-stage dehydration process and mechanism of the thermal decomposition of SrB6O10·5H2O were established elementarily.The apparent activation energy and pre-exponential factor were also acquired.
Flaky hydrated strontium borate(SrB6O10·5H2O) was synthesized by liquid-phase precipitation method with strontium chloride and ammonium hydrogen borate as the raw materials.The product was characterized by XRD,FT-IR and SEM.The thermal decomposition Kinetics of SrB6O10·5H2O was studied by thermogravimetric analysis.The data of TG-DTA was analyzed by isoconversional non-linear and Coats-Redfern methods.The four-stage dehydration process and mechanism of the thermal decomposition of SrB6O10·5H2O were established elementarily.The apparent activation energy and pre-exponential factor were also acquired.
2009, 26(6): 702-706
Abstract:
MnO2 thin film was electrodeposited onto aligned carbon nanotubes(ACNTs) electrode in the electrolyte containing 0.2 mol/L Mn(CH3COO)2 and 0.1 mol/L Na2SO4 at pH=6.0.As observed by means of scanning electron microscopy,the resulting MnO2 film on those nanotubes exhibited hole-like microstru-cture.Such-prepared MnO2-modified ACNTs nanocomposite was then characterized by cyclic voltammograms,charge-discharge curve and electrochemical impedance measurements etc.,and it showed excellent capacitive behavior between 0~0.6 V(vs.Ag/AgCl) in 1 mol/L KCl aqueous solution.The specific capacitance of the ACNT electrode was calculated to be 16 F/g before the MnO2 film modification,and increased to 330 F/g after the MnO2 film deposition due to the special Faradic capacitance of MnO2.After scaning for 200 cycles,there was a little change for its cyclic voltammogram curve,indicating good reversible and capacitive property of the MnO2-ACNTs composite.
MnO2 thin film was electrodeposited onto aligned carbon nanotubes(ACNTs) electrode in the electrolyte containing 0.2 mol/L Mn(CH3COO)2 and 0.1 mol/L Na2SO4 at pH=6.0.As observed by means of scanning electron microscopy,the resulting MnO2 film on those nanotubes exhibited hole-like microstru-cture.Such-prepared MnO2-modified ACNTs nanocomposite was then characterized by cyclic voltammograms,charge-discharge curve and electrochemical impedance measurements etc.,and it showed excellent capacitive behavior between 0~0.6 V(vs.Ag/AgCl) in 1 mol/L KCl aqueous solution.The specific capacitance of the ACNT electrode was calculated to be 16 F/g before the MnO2 film modification,and increased to 330 F/g after the MnO2 film deposition due to the special Faradic capacitance of MnO2.After scaning for 200 cycles,there was a little change for its cyclic voltammogram curve,indicating good reversible and capacitive property of the MnO2-ACNTs composite.
2009, 26(6): 707-710
Abstract:
A series of 3-alkylthiophene copolymers,poly[(2,4-bisvinyl-3-hexylthiophene-co-2,5-bisphenyl-1,3,4-oxadiazole](P3HT-OXD),poly[(2,4-bisvinyl-3-octylthiophene)-co-2,5-bisphenyl-1,3,4-Oxa-diazole)](P3OT-OXD),poly[(2,4-bisvinyl-3-hexylthiophene)-co-2,6-pyridine](P3HT-Py),and poly[(2,4-bisvinyl-3-octylthiophene)-co-2,6-pyridine](P3OT-Py) were synthesized by Heck Coupling approach.Their structures were characterized by NMR and gel permeation chromatography(GPC).The photoelectric properties were investigated using cyclic voltammetry and UV-Vis spectroscopy.The results indicated that the ionization potential(Ip) and band gap(Eg) of the copolymers were reduced with an increase of the length of the alkyl chain.The band gap of P3OT-OXD was 0.11 eV lower than that of P3HT-OXD,and the band gap of P3OT-Py was 0.19 eV lower than that of P3HT-Py.Electron affinity(Ea) of polythiophene containing 1,3,4-oxadiazole in main chain was comparatively high,which will be avail to enhance electron-transpo-rting effect and improve the balanced rates for electron and hole injection.
A series of 3-alkylthiophene copolymers,poly[(2,4-bisvinyl-3-hexylthiophene-co-2,5-bisphenyl-1,3,4-oxadiazole](P3HT-OXD),poly[(2,4-bisvinyl-3-octylthiophene)-co-2,5-bisphenyl-1,3,4-Oxa-diazole)](P3OT-OXD),poly[(2,4-bisvinyl-3-hexylthiophene)-co-2,6-pyridine](P3HT-Py),and poly[(2,4-bisvinyl-3-octylthiophene)-co-2,6-pyridine](P3OT-Py) were synthesized by Heck Coupling approach.Their structures were characterized by NMR and gel permeation chromatography(GPC).The photoelectric properties were investigated using cyclic voltammetry and UV-Vis spectroscopy.The results indicated that the ionization potential(Ip) and band gap(Eg) of the copolymers were reduced with an increase of the length of the alkyl chain.The band gap of P3OT-OXD was 0.11 eV lower than that of P3HT-OXD,and the band gap of P3OT-Py was 0.19 eV lower than that of P3HT-Py.Electron affinity(Ea) of polythiophene containing 1,3,4-oxadiazole in main chain was comparatively high,which will be avail to enhance electron-transpo-rting effect and improve the balanced rates for electron and hole injection.
2009, 26(6): 711-715
Abstract:
Nano-scale nickel hydroxide was synthesized by micro-emulsion and its structure,surface morpho-logy and electrochemical performance were tested and analyzed by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),galvanostatic charge/discharge,cyclic voltammetry and electrochemical impedance spectroscopy.The results show that nano-scale nickel hydroxide turned to different morphologies after hydrothermal and micro-emulsion/hydrothermal modification.Though the results of the activation performance of unsettled and treated nano-scale nickel hydroxide were uniform,the discharging specific capacity of nano-scale nickel hydroxide was different.The discharging specific capacity of nano-scale nickel hydroxide,which underwent hydrothermal treatment at 140 ℃,was increased by 24.6 mA·h/g,while the nano-scale nickel hydroxide,which underwent micro-emulsion/hydrothermal treatment,was increased by 74.8 mA·h/g.The peak current of cyclic voltammetry also increased and the charge-transfer resistances decreased from 2.633 Ω to 2.464 Ω and 1.679 Ω respectively.
Nano-scale nickel hydroxide was synthesized by micro-emulsion and its structure,surface morpho-logy and electrochemical performance were tested and analyzed by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),galvanostatic charge/discharge,cyclic voltammetry and electrochemical impedance spectroscopy.The results show that nano-scale nickel hydroxide turned to different morphologies after hydrothermal and micro-emulsion/hydrothermal modification.Though the results of the activation performance of unsettled and treated nano-scale nickel hydroxide were uniform,the discharging specific capacity of nano-scale nickel hydroxide was different.The discharging specific capacity of nano-scale nickel hydroxide,which underwent hydrothermal treatment at 140 ℃,was increased by 24.6 mA·h/g,while the nano-scale nickel hydroxide,which underwent micro-emulsion/hydrothermal treatment,was increased by 74.8 mA·h/g.The peak current of cyclic voltammetry also increased and the charge-transfer resistances decreased from 2.633 Ω to 2.464 Ω and 1.679 Ω respectively.
2009, 26(6): 716-720
Abstract:
A novel amperometric penicillin immunosensor was prepared by co-immobilizing new methylene blue(NMB) and horseradish peroxidase(HRP)-labeled penicillin polyclonal antibody(Ab*) on a glassy carbon electrode(GCE) pretreated by electrochemical oxidation and tailored with glutaraldehyde(GA) as the cross-linker through covalent bonding.The quantitative determination of residual penicillin in chicken muscle was investigated through cyclic voltammetry.The experiment results showed that the dependence of current on the concentration of residual penicillin was linear in a range of 5～45 ng/g,and the correlation coefficient was 0.974 7,and the detection limit 1.90 ng/g.The test of the effect of precipitation showed that saturated ammonium sulfate was the best one among the three precipitators.Sample recovery rate was up to 74.5%.At the same time,interference experiment showed that the chicken cross-interference and interference from other components were small.Modified electrode had a good stability and can be used for the determination of penicillin in actual chicken samples.
A novel amperometric penicillin immunosensor was prepared by co-immobilizing new methylene blue(NMB) and horseradish peroxidase(HRP)-labeled penicillin polyclonal antibody(Ab*) on a glassy carbon electrode(GCE) pretreated by electrochemical oxidation and tailored with glutaraldehyde(GA) as the cross-linker through covalent bonding.The quantitative determination of residual penicillin in chicken muscle was investigated through cyclic voltammetry.The experiment results showed that the dependence of current on the concentration of residual penicillin was linear in a range of 5～45 ng/g,and the correlation coefficient was 0.974 7,and the detection limit 1.90 ng/g.The test of the effect of precipitation showed that saturated ammonium sulfate was the best one among the three precipitators.Sample recovery rate was up to 74.5%.At the same time,interference experiment showed that the chicken cross-interference and interference from other components were small.Modified electrode had a good stability and can be used for the determination of penicillin in actual chicken samples.
2009, 26(6): 721-725
Abstract:
With lead ion(Ⅱ) as the template,sodium vinylbenzoic-acid as the functional monomer and divinyl benzene as the cross-linking agent,lead molecularly imprinted polymers(Pb-MIPs) were synthesized with preassembling and surface-imprinting technology.The structure of Pb-MIPs was characterized with FT-IR spectroscopy and specific surface area determination,and the adsorption properties and selective recognition of Pb-MIPs for lead ions were also studied.The results show that Pb-MIPs has a high adsorption capacity and good selective recognition for lead ions,and the maximum adsorption capacity of Pb-MIPs is 725 μg/g.Pb-MIPs was applied to the determination of trace lead in water samples by graphite furnace atomic absorption spectrometry,where if showed a significant improvement on the detection.
With lead ion(Ⅱ) as the template,sodium vinylbenzoic-acid as the functional monomer and divinyl benzene as the cross-linking agent,lead molecularly imprinted polymers(Pb-MIPs) were synthesized with preassembling and surface-imprinting technology.The structure of Pb-MIPs was characterized with FT-IR spectroscopy and specific surface area determination,and the adsorption properties and selective recognition of Pb-MIPs for lead ions were also studied.The results show that Pb-MIPs has a high adsorption capacity and good selective recognition for lead ions,and the maximum adsorption capacity of Pb-MIPs is 725 μg/g.Pb-MIPs was applied to the determination of trace lead in water samples by graphite furnace atomic absorption spectrometry,where if showed a significant improvement on the detection.
2009, 26(6): 726-729
Abstract:
An o-phenanthroline-substituted ruthenium complex,[Rubis(bipyridyl)(3,4,7,8-tetrachrolo-1,10-phenanthroline)](PF6)2,was synthesized and the structure of the complex was characterized by elemental analysis,IR spectroscopy and 1H NMR spectroscopy.The complex displayed absorption in the UV and visible regions,with a visible maximum absorption at 440 nm,a typical metal-to-ligand charge transfer(MLCT) transition.Photoluminescence emission also had the characteristics of MLCT transitions with the maxima wavelengths ranged from 630 to 649 nm depending on the solvent.The electrochemiluminescence(ECL) of the complex was found to be less dependant on pH,which was distinctly different from that of the well known ruthenium tris(bipyridine) complex.Furthermore the background ECL signal of the complex did not increase even under a strong alkaline condition.
An o-phenanthroline-substituted ruthenium complex,[Rubis(bipyridyl)(3,4,7,8-tetrachrolo-1,10-phenanthroline)](PF6)2,was synthesized and the structure of the complex was characterized by elemental analysis,IR spectroscopy and 1H NMR spectroscopy.The complex displayed absorption in the UV and visible regions,with a visible maximum absorption at 440 nm,a typical metal-to-ligand charge transfer(MLCT) transition.Photoluminescence emission also had the characteristics of MLCT transitions with the maxima wavelengths ranged from 630 to 649 nm depending on the solvent.The electrochemiluminescence(ECL) of the complex was found to be less dependant on pH,which was distinctly different from that of the well known ruthenium tris(bipyridine) complex.Furthermore the background ECL signal of the complex did not increase even under a strong alkaline condition.
2009, 26(6): 730-733
Abstract:
5-Nitrosalicylic acid can react with human serum albumin(HSA) to form a complex.Based on this,a new method for the determination of proteins by synchronous fluorescence spectra under simulated physiological conditions was established with 5-nitrosalicylic acid as a fluorescence probe.The spectral chara-cterization and the intensity of synchronous fluorescence were related to the value of Δλ,reaction medium and reaction temperature is.Experimental results show that under the optimum conditions,the synchronous fluorescence intensity of the system is in proportion to the concentration of HSA in a range of 3.2×10-8~6.4×10-6 mg/L.The detection limit is 1.17×10-8 mol/L(n=11).The determination of proteins in human serum,urine and saliva samples is performed with satisfactory results,the recovery is within a range of 99.96%~100.04%.
5-Nitrosalicylic acid can react with human serum albumin(HSA) to form a complex.Based on this,a new method for the determination of proteins by synchronous fluorescence spectra under simulated physiological conditions was established with 5-nitrosalicylic acid as a fluorescence probe.The spectral chara-cterization and the intensity of synchronous fluorescence were related to the value of Δλ,reaction medium and reaction temperature is.Experimental results show that under the optimum conditions,the synchronous fluorescence intensity of the system is in proportion to the concentration of HSA in a range of 3.2×10-8~6.4×10-6 mg/L.The detection limit is 1.17×10-8 mol/L(n=11).The determination of proteins in human serum,urine and saliva samples is performed with satisfactory results,the recovery is within a range of 99.96%~100.04%.
2009, 26(6): 734-737
Abstract:
It has been observed that pyrocatechol and m-phenylenediamin can sensitively inhibit the discoloration of neutral red oxidation by H2O2 in the presence of catalyst Fe(Ⅲ) in dilute sulfuric acid solution.The inhibitory effects of the two organic compounds do not show additive properties.Based on this result,the advantages of artificial neural network were adopted to handle the experimental data and a new inhibitory kinetic spectrophotometry assisted with artificial neural networks for the simultaneous determination of pyro-catechol and m-phenylenediamin was established.The method has been applied to simultaneously determine 5 groups of pyrocatechol and m-phenylenediamin with results of recoveries from 96.8% to 104.4%,respectively.
It has been observed that pyrocatechol and m-phenylenediamin can sensitively inhibit the discoloration of neutral red oxidation by H2O2 in the presence of catalyst Fe(Ⅲ) in dilute sulfuric acid solution.The inhibitory effects of the two organic compounds do not show additive properties.Based on this result,the advantages of artificial neural network were adopted to handle the experimental data and a new inhibitory kinetic spectrophotometry assisted with artificial neural networks for the simultaneous determination of pyro-catechol and m-phenylenediamin was established.The method has been applied to simultaneously determine 5 groups of pyrocatechol and m-phenylenediamin with results of recoveries from 96.8% to 104.4%,respectively.
2009, 26(6): 738-741
Abstract:
A novel sample introduction system for the determination of Sb by electrochemical hydride generation in a phosphate buffer solution(PBS) was developed.It was found that using neutral PBS as electrolytic solution could markedly increase the fluorescence intensity of Sb(Ⅲ) and suppress totally the signal of Sb(Ⅴ).The valence analysis of Sb could be carried out in buffer solution.Moreover,it has some merits like reducing self-erodible effect of the cathode material,prolonging the lifetime of the cell and increasing the signal stability.The traditional thin-type cell was improved and a new cell with screw-thread was developed.Assembly time of the disk cell was only about 1 min,shortened largely compared with that for the traditional cells of about 20 min.Furthermore,sealing performance of this cell was better than that of the traditional electrolytic.The detection limit(3σ) and the precisions(n=11) for 20 μg/L Sb(Ⅲ) were 0.038 μg/L Sb(Ⅲ) and 3.9%,respectively.This system has been applied satisfactorily to the determination of Sb in soil samples.
A novel sample introduction system for the determination of Sb by electrochemical hydride generation in a phosphate buffer solution(PBS) was developed.It was found that using neutral PBS as electrolytic solution could markedly increase the fluorescence intensity of Sb(Ⅲ) and suppress totally the signal of Sb(Ⅴ).The valence analysis of Sb could be carried out in buffer solution.Moreover,it has some merits like reducing self-erodible effect of the cathode material,prolonging the lifetime of the cell and increasing the signal stability.The traditional thin-type cell was improved and a new cell with screw-thread was developed.Assembly time of the disk cell was only about 1 min,shortened largely compared with that for the traditional cells of about 20 min.Furthermore,sealing performance of this cell was better than that of the traditional electrolytic.The detection limit(3σ) and the precisions(n=11) for 20 μg/L Sb(Ⅲ) were 0.038 μg/L Sb(Ⅲ) and 3.9%,respectively.This system has been applied satisfactorily to the determination of Sb in soil samples.
2009, 26(6): 742-745
Abstract:
A new method was proposed for the determination of carbocisteine(S-CMC) with 1,2-naphthoquinone-4-sulfonate(NQS) by spectrophotometry.It was indicated that the molar ratio of the russety product formed by S-CMC,Zeph and NQS was 1:1:1 at pH=11.00.The linear regression equation was A=0.223 02+0.011 98c(mg/L),with a correlation coefficient of 0.999 2,and ε was 2.2×103 L/(mol·cm) at 466 nm.Beer's law was well obeyed in a S-CMC concentration range of 0.72～28.67 mg/L.The limit of detection(3σ/κ) was 0.70 mg/L,and the RSD was 0.52%,and the average recovery rate was in a range of 98.7%～102.6%.The method was used for the determination of S-CMC in pharmaceutical samples with satisfactory results.
A new method was proposed for the determination of carbocisteine(S-CMC) with 1,2-naphthoquinone-4-sulfonate(NQS) by spectrophotometry.It was indicated that the molar ratio of the russety product formed by S-CMC,Zeph and NQS was 1:1:1 at pH=11.00.The linear regression equation was A=0.223 02+0.011 98c(mg/L),with a correlation coefficient of 0.999 2,and ε was 2.2×103 L/(mol·cm) at 466 nm.Beer's law was well obeyed in a S-CMC concentration range of 0.72～28.67 mg/L.The limit of detection(3σ/κ) was 0.70 mg/L,and the RSD was 0.52%,and the average recovery rate was in a range of 98.7%～102.6%.The method was used for the determination of S-CMC in pharmaceutical samples with satisfactory results.
2009, 26(6): 746-748
Abstract:
The second-generation 1,4-dihydropyridine calcium antagonist nitrendipine was synthesized through the cyclocondensation process of ethyl 2-(3-nitrobenzylidene) acetoacetate and methyl 3-aminocrotonate in an ionic liquid,n-butyl pyridinium tetrafluoroborate,at 100~110 ℃ for 3 h in a yield of 95%.The ionic liquid can be recycled at 90% recovery,and can be reused at least 5 times without loss in activity.
The second-generation 1,4-dihydropyridine calcium antagonist nitrendipine was synthesized through the cyclocondensation process of ethyl 2-(3-nitrobenzylidene) acetoacetate and methyl 3-aminocrotonate in an ionic liquid,n-butyl pyridinium tetrafluoroborate,at 100~110 ℃ for 3 h in a yield of 95%.The ionic liquid can be recycled at 90% recovery,and can be reused at least 5 times without loss in activity.
