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2005 Volume 22 Issue 9
2005, 22(9): 929-932
Abstract:
The performance of formic acid used as the methanol-alternative fuel in the direct methanol fuel cell was studied.It was found that although the energy density of formic acid is lower than 1/3 of that of methanol,formic acid is still a good methanol-alternative fuel and could be hopeful to be used because the electrochemical oxidation of formic acid at the Pt-Ru/C electrode is much better than that of methanol.For example,the peak potential and onset potential of the oxidation peak of formic acid at the Pt-Ru/C electrode are 120 and 300 mV more negative than those of methanol,respectively.In addition,the permeability of formic acid through the Nafion membrane is only 1/5 that of methanol.
The performance of formic acid used as the methanol-alternative fuel in the direct methanol fuel cell was studied.It was found that although the energy density of formic acid is lower than 1/3 of that of methanol,formic acid is still a good methanol-alternative fuel and could be hopeful to be used because the electrochemical oxidation of formic acid at the Pt-Ru/C electrode is much better than that of methanol.For example,the peak potential and onset potential of the oxidation peak of formic acid at the Pt-Ru/C electrode are 120 and 300 mV more negative than those of methanol,respectively.In addition,the permeability of formic acid through the Nafion membrane is only 1/5 that of methanol.
2005, 22(9): 933-936
Abstract:
Fourteen new O-methyl-α-hydroxyalkyl phosphonate monosalts were synthesized and characterized by means of IR,1H NMR and elemental analysis.Their plant growth regulation activities for wheat and cucumber seedling were examined.The compound Ⅰk exhibits higher stimulating activity towards cucumber root growth at a dosage of 10 μg/g.
Fourteen new O-methyl-α-hydroxyalkyl phosphonate monosalts were synthesized and characterized by means of IR,1H NMR and elemental analysis.Their plant growth regulation activities for wheat and cucumber seedling were examined.The compound Ⅰk exhibits higher stimulating activity towards cucumber root growth at a dosage of 10 μg/g.
2005, 22(9): 937-941
Abstract:
A giant magnetic impedance(GMI) effect of complex wires produced by electrodepositing CoP amorphous alloy on cylindrical Cu substrates was studied.The conditions for fabricating CoP amorphous alloy deposits with excellent soft magnetic property were investigated in detail.The P content and soft magnetic property of the alloy deposite depend greatly on cathode deposition current density.When the cathode deposition current density is setting from 16.9×10-3 A/cm2 to 25.3×10-3 A/cm2,the magnetic property of the CoP alloy deposits is quite soft,the GMI effect of the complex wires is very great and all of GMI ratios are beyond 200%,the best of all the GMI ratios is 441%,the best magnetic field sensitive degree is 0.2%/(A·m-1).The measurement result of the dependence of GMI effect on AC frequency shows that its charicteristic frequency is 400 kHz.
A giant magnetic impedance(GMI) effect of complex wires produced by electrodepositing CoP amorphous alloy on cylindrical Cu substrates was studied.The conditions for fabricating CoP amorphous alloy deposits with excellent soft magnetic property were investigated in detail.The P content and soft magnetic property of the alloy deposite depend greatly on cathode deposition current density.When the cathode deposition current density is setting from 16.9×10-3 A/cm2 to 25.3×10-3 A/cm2,the magnetic property of the CoP alloy deposits is quite soft,the GMI effect of the complex wires is very great and all of GMI ratios are beyond 200%,the best of all the GMI ratios is 441%,the best magnetic field sensitive degree is 0.2%/(A·m-1).The measurement result of the dependence of GMI effect on AC frequency shows that its charicteristic frequency is 400 kHz.
2005, 22(9): 942-945
Abstract:
The effects of pH on the emulsion and prepolymer solution stability,morphologies and properties of the microcapsules were studied in the fabrication of microencapsulated n-octadecane by in-situ polymerization of melamine-formaldehyde.The pH value in the range of 6.5~9.0 does not significantly affect the stability of the emulsion.The prepolymer of melamine-formaldehyde is easy to polymerize in the acid solution,however,it is hard to polymerize in the alkaline solution.The separation time of the prepolymer solution is prolonged with the increase of pH value,and shortened with the increase of temperature.The residual formaldehyde exists in the melamine-formaldehyde polymer when the pH value is low.The microcapsules are perfect sphere and are dispersed well when the pH value of polymerization system is 4~5.Both the enthalpy and thermal stable temperature of the microcapsules increase with the rise of pH value;however,the pH value in the range of 4~5 is preferable due to the dispersity and reaction period of the microcapsules.
The effects of pH on the emulsion and prepolymer solution stability,morphologies and properties of the microcapsules were studied in the fabrication of microencapsulated n-octadecane by in-situ polymerization of melamine-formaldehyde.The pH value in the range of 6.5~9.0 does not significantly affect the stability of the emulsion.The prepolymer of melamine-formaldehyde is easy to polymerize in the acid solution,however,it is hard to polymerize in the alkaline solution.The separation time of the prepolymer solution is prolonged with the increase of pH value,and shortened with the increase of temperature.The residual formaldehyde exists in the melamine-formaldehyde polymer when the pH value is low.The microcapsules are perfect sphere and are dispersed well when the pH value of polymerization system is 4~5.Both the enthalpy and thermal stable temperature of the microcapsules increase with the rise of pH value;however,the pH value in the range of 4~5 is preferable due to the dispersity and reaction period of the microcapsules.
2005, 22(9): 946-949
Abstract:
Synthetic methods of tri-substituted aminobenzaldehyde hydrazones,used as hole transport materials (HTM),were studied.2-Methyl-4-dibenzylaminobenzaldehyde-1,1-diphenydrazone,2-methyl-4-(N-ethyl-N-benzyl)aminobenzaldehyde-1,1-diphenydrazone,4-(N-ethyl-N-benzyl)aminobenzaldehyde-1,1-diphenydrazone and 4-bis(p-methylphenyl)aminobenzaldehyde-1,1-diphenydrazone were prepared by the(reaction) of substituted aromatic aldehydes with 1,1-diphenylhydrazine,and their yields were from 82% to 98%.The compositions and structures of the products were characterized by means of UV,IR,MS and elemental analysis.The HPLC purity is higher than 99.4%.The double-layer organic photoconductors were fabricated with the above four compounds as HTM. The tested results of the photoconductors show that hydrazone a and hydrazone d have excellent photographic performance.
Synthetic methods of tri-substituted aminobenzaldehyde hydrazones,used as hole transport materials (HTM),were studied.2-Methyl-4-dibenzylaminobenzaldehyde-1,1-diphenydrazone,2-methyl-4-(N-ethyl-N-benzyl)aminobenzaldehyde-1,1-diphenydrazone,4-(N-ethyl-N-benzyl)aminobenzaldehyde-1,1-diphenydrazone and 4-bis(p-methylphenyl)aminobenzaldehyde-1,1-diphenydrazone were prepared by the(reaction) of substituted aromatic aldehydes with 1,1-diphenylhydrazine,and their yields were from 82% to 98%.The compositions and structures of the products were characterized by means of UV,IR,MS and elemental analysis.The HPLC purity is higher than 99.4%.The double-layer organic photoconductors were fabricated with the above four compounds as HTM. The tested results of the photoconductors show that hydrazone a and hydrazone d have excellent photographic performance.
2005, 22(9): 950-953
Abstract:
A stable Lysine monolayer was obtained on the surface of glassy carbon electrode(GCE) by means of electrochemical oxidation method.The electrostatic repulsion of the monolayer to Fe(CN)63- redox probe was investigated via cyclic voltammetry at different pH values and different concentrations of cations with different charges,respectively.The result show that the electrostatic repulsion of Lysine monolayer decreases with the increase of pH value from 1.5 to 9.7,and also decreases with the addition of Ca2+ or Al3+.Furthermore,the electrostatic repulsion decreases with the increase of the concentration of Ca2+.Thus,it is feasible to change the charged state of carbon surface by linking Lysine to carbon surface via electrochemical oxidation that then makes the carbon surfaces have the electrostatic repulsion to negatively charged matter.
A stable Lysine monolayer was obtained on the surface of glassy carbon electrode(GCE) by means of electrochemical oxidation method.The electrostatic repulsion of the monolayer to Fe(CN)63- redox probe was investigated via cyclic voltammetry at different pH values and different concentrations of cations with different charges,respectively.The result show that the electrostatic repulsion of Lysine monolayer decreases with the increase of pH value from 1.5 to 9.7,and also decreases with the addition of Ca2+ or Al3+.Furthermore,the electrostatic repulsion decreases with the increase of the concentration of Ca2+.Thus,it is feasible to change the charged state of carbon surface by linking Lysine to carbon surface via electrochemical oxidation that then makes the carbon surfaces have the electrostatic repulsion to negatively charged matter.
2005, 22(9): 954-957
Abstract:
Hyperbranched polyester-encapsulated silver nanocrystals with a particle size of 3~19 nm,(averaged) size being(7.7±0.5) nm,were prepared by ultraviolet irradiation of silver ions in the mixture of -OH and -COOH groups functionalized hyperbranched polyester and P-containing surfactant (MOA-3PK).The silver nanoparticles were characterized by means of transmission electron microscopy,selected area electron diffraction technique,UV-Vis spectrometry,X-ray diffraction,X-ray photoelectron spectrometry and Fourier Transform Infrared spectroscopy.Controlled experiments show that non-aggregated silver nanoarticles could not be prepared without either hyperbranched polyester or P-containing surfactant,indicating the important role of the combination of hyperbranched polyester with P-containing surfactant in stabilizing silver nanoparticles during the photoreduction.
Hyperbranched polyester-encapsulated silver nanocrystals with a particle size of 3~19 nm,(averaged) size being(7.7±0.5) nm,were prepared by ultraviolet irradiation of silver ions in the mixture of -OH and -COOH groups functionalized hyperbranched polyester and P-containing surfactant (MOA-3PK).The silver nanoparticles were characterized by means of transmission electron microscopy,selected area electron diffraction technique,UV-Vis spectrometry,X-ray diffraction,X-ray photoelectron spectrometry and Fourier Transform Infrared spectroscopy.Controlled experiments show that non-aggregated silver nanoarticles could not be prepared without either hyperbranched polyester or P-containing surfactant,indicating the important role of the combination of hyperbranched polyester with P-containing surfactant in stabilizing silver nanoparticles during the photoreduction.
2005, 22(9): 958-961
Abstract:
The O2·- and ·OH scavenging activities of DMW chitosans and sulfated chitosans of correspon-ding molecular weight were investigated.Colorimetric method was used,by which phenzine methosulphate(PMS)/dinucleotide-reduced(NADH) and Fe/H2O2 were used as producing reagent and Nitro blue tetrazo-lium(NBT) and Fanhonghua as detecting reagent for O2·- and ·OH.We obtained several satisfied results,as follows:Firstly,low molecular weight chitosans and their derivatives show stronger scavenging effects on O2·- and ·OH than high molecular weight chitosan and their derivatives.For example,when the mass concentration of samples is 1.6 g/L,the O2·- scavenging activity of low molecular weight chitosan(9×103) and high molecular weight chitosan(7.6×105) are 85.86% and 35.50% respectively.Secondly,compared with DMW chitosans,DMW sulfated chitosans show stronger inhibition effect on O2·-.At 0.05 g/L,the scavenging activity on O2·- reaches to 86.26% for low molecular weight chitosan sulfate(9×105),but that of low molecular) weight chitosan(9×103) is 85.86% when mass concentration of the sample is 1.6 g/L.Thirdly,scavenging activity of chitosan sulfates(9×103,89.82%,1.2×105,59.68%,3.2 g/L) on OH is between those of low molecular weight chitosan(9×103,91.22%,3.2 g/L) and high molecular weight chitosan(1.2×105,44.11%,7.6×105,16.77%,3.2 g/L).Fourthly,low molecular weight chitosan sulfates show more effective scavenging activities on O2·- and ·OH than high molecular weight chitosan sulfates.Finally,the scavenging activities of DMW chitosan and their sulfated derivatives increase with the increase in their mass concentration.However,sulfated chitosans show quite strong scavenging action on O2·-.At 0.2 g/L,the scavenging activities reach to 95.87% and 91.96% respectively,but their scavenging activities barely increase over 0.2 g/L.This result also shows sulfated chitosans are very effective antioxidant.
The O2·- and ·OH scavenging activities of DMW chitosans and sulfated chitosans of correspon-ding molecular weight were investigated.Colorimetric method was used,by which phenzine methosulphate(PMS)/dinucleotide-reduced(NADH) and Fe/H2O2 were used as producing reagent and Nitro blue tetrazo-lium(NBT) and Fanhonghua as detecting reagent for O2·- and ·OH.We obtained several satisfied results,as follows:Firstly,low molecular weight chitosans and their derivatives show stronger scavenging effects on O2·- and ·OH than high molecular weight chitosan and their derivatives.For example,when the mass concentration of samples is 1.6 g/L,the O2·- scavenging activity of low molecular weight chitosan(9×103) and high molecular weight chitosan(7.6×105) are 85.86% and 35.50% respectively.Secondly,compared with DMW chitosans,DMW sulfated chitosans show stronger inhibition effect on O2·-.At 0.05 g/L,the scavenging activity on O2·- reaches to 86.26% for low molecular weight chitosan sulfate(9×105),but that of low molecular) weight chitosan(9×103) is 85.86% when mass concentration of the sample is 1.6 g/L.Thirdly,scavenging activity of chitosan sulfates(9×103,89.82%,1.2×105,59.68%,3.2 g/L) on OH is between those of low molecular weight chitosan(9×103,91.22%,3.2 g/L) and high molecular weight chitosan(1.2×105,44.11%,7.6×105,16.77%,3.2 g/L).Fourthly,low molecular weight chitosan sulfates show more effective scavenging activities on O2·- and ·OH than high molecular weight chitosan sulfates.Finally,the scavenging activities of DMW chitosan and their sulfated derivatives increase with the increase in their mass concentration.However,sulfated chitosans show quite strong scavenging action on O2·-.At 0.2 g/L,the scavenging activities reach to 95.87% and 91.96% respectively,but their scavenging activities barely increase over 0.2 g/L.This result also shows sulfated chitosans are very effective antioxidant.
2005, 22(9): 962-966
Abstract:
The Sb2O3 nanoparticles prepared with SbCl3 via alcoholysis,hydrolysis and processing with the surfactants,were assembled onto mica substrates.The crystal phase,morphology and the assembling behavior of nano-Sb2O3 on mica were analyzed by means of XRD,TEM and SEM.The flame retardant properties and mechanisms of nano-Sb2O3 and nano-Sb2O3/mica complex were studied by combustion test and thermal analysis.The results show that the Sb2O3 nanoparticles prepared by this method are cubic crystal,which can be assembled uniformly onto the mica substrate.The nano-Sb2O3 particles are characteristic of small size,narrow size distribution,uniform crystal and monodispersed particles can be obtained.Compared with micron-Sb2O3,the nano-Sb2O3 shows more excellent flame retardant properties.The mass loss of nano-Sb2O3/mica complex is 13.5% higher than that of nano-Sb2O3.Compared with nano-Sb2O3,the plateau range of the mass loss temperature of nano-Sb2O3 coordinated with chlorinated paraffin is decreased by about 300℃,the mass loss is increased by about 63.2% and the Absorption peak area increases appreciably.Nano-Sb2O3/mica complexes show the same coordinating effect as chlorinated paraffin and possess excellent flame retardant properties.
The Sb2O3 nanoparticles prepared with SbCl3 via alcoholysis,hydrolysis and processing with the surfactants,were assembled onto mica substrates.The crystal phase,morphology and the assembling behavior of nano-Sb2O3 on mica were analyzed by means of XRD,TEM and SEM.The flame retardant properties and mechanisms of nano-Sb2O3 and nano-Sb2O3/mica complex were studied by combustion test and thermal analysis.The results show that the Sb2O3 nanoparticles prepared by this method are cubic crystal,which can be assembled uniformly onto the mica substrate.The nano-Sb2O3 particles are characteristic of small size,narrow size distribution,uniform crystal and monodispersed particles can be obtained.Compared with micron-Sb2O3,the nano-Sb2O3 shows more excellent flame retardant properties.The mass loss of nano-Sb2O3/mica complex is 13.5% higher than that of nano-Sb2O3.Compared with nano-Sb2O3,the plateau range of the mass loss temperature of nano-Sb2O3 coordinated with chlorinated paraffin is decreased by about 300℃,the mass loss is increased by about 63.2% and the Absorption peak area increases appreciably.Nano-Sb2O3/mica complexes show the same coordinating effect as chlorinated paraffin and possess excellent flame retardant properties.
2005, 22(9): 967-970
Abstract:
The experimental results about the aliphatic amine modified bentonnites show that the hydrophobic interaction between the alkyl chains obviously increases the molar adsorption quantities q(org) of the aliphatic amine in the domain between the layers of bentonnite and effectively expands the distance d between the layers.The q(org) and d increase with increasing acid content in the solutions.When the molar ratio of sulfuric acid to aliphatic amine in solution is fixed to be 0.92,q(org)s of dodecylamine,hexadecylamine and octadecylamine are 0.572,1.50 and 1.69 mmol/g,and d's are 2.21,2.51 and 2.58 nm,respectively.The latter values are much larger than that of Na-bentonnite(d=0.250 nm).
The experimental results about the aliphatic amine modified bentonnites show that the hydrophobic interaction between the alkyl chains obviously increases the molar adsorption quantities q(org) of the aliphatic amine in the domain between the layers of bentonnite and effectively expands the distance d between the layers.The q(org) and d increase with increasing acid content in the solutions.When the molar ratio of sulfuric acid to aliphatic amine in solution is fixed to be 0.92,q(org)s of dodecylamine,hexadecylamine and octadecylamine are 0.572,1.50 and 1.69 mmol/g,and d's are 2.21,2.51 and 2.58 nm,respectively.The latter values are much larger than that of Na-bentonnite(d=0.250 nm).
2005, 22(9): 971-975
Abstract:
C60Pd(Ph2POCH2CH2OPPh2) complex was prepared in inert atmosphere via replacement reaction and characterized by mean of elemental analysis,IR,electronic spectra,XPS and XRD methods.The redox properties and thermostability of the title complex were studied,moreover the photovoltaic effect for C60Pd(Ph2POCH2CH2OPPh2) complex to form n+n heterojunction on a GaAs electrode in photoelectrochemical cell was investigated.The result shows that I3-/I- is the best redox couple in the photoelectrochemical cell.The photovoltaic property of C60Pd(Ph2POCH2CH2OPPh2)-GaAs electrode at 1 μm for thickness of C60Pd(Ph2POCH2CH2OPPh2) film is the best.
C60Pd(Ph2POCH2CH2OPPh2) complex was prepared in inert atmosphere via replacement reaction and characterized by mean of elemental analysis,IR,electronic spectra,XPS and XRD methods.The redox properties and thermostability of the title complex were studied,moreover the photovoltaic effect for C60Pd(Ph2POCH2CH2OPPh2) complex to form n+n heterojunction on a GaAs electrode in photoelectrochemical cell was investigated.The result shows that I3-/I- is the best redox couple in the photoelectrochemical cell.The photovoltaic property of C60Pd(Ph2POCH2CH2OPPh2)-GaAs electrode at 1 μm for thickness of C60Pd(Ph2POCH2CH2OPPh2) film is the best.
2005, 22(9): 976-979
Abstract:
N-Butyl alcohol was used as surface treatment agent to prepare columned nano-hydroxyapatite(HA)(L/D ratio is about 2.5/1) via azeotropic distillation based on chemical co-deposited method.The samples were characterized by XRD,TEM,DSC and FT-IR means.n-Butyl alcohol could dehydrate with the hydroxyl groups on the HA surface to form C-O-P bonds,so the -O-4H9 groups were grafted on HA particles.Compared with the untreated HA,the crystalline temperature of HA treated with n-butyl-alcohol was decreased by two hundred centigrade,the crystallite dimension of HA treated with nbutyl alcohol was reduced by two thirds,moreover,the particle aggregation phenomena was decreased obviously.
N-Butyl alcohol was used as surface treatment agent to prepare columned nano-hydroxyapatite(HA)(L/D ratio is about 2.5/1) via azeotropic distillation based on chemical co-deposited method.The samples were characterized by XRD,TEM,DSC and FT-IR means.n-Butyl alcohol could dehydrate with the hydroxyl groups on the HA surface to form C-O-P bonds,so the -O-4H9 groups were grafted on HA particles.Compared with the untreated HA,the crystalline temperature of HA treated with n-butyl-alcohol was decreased by two hundred centigrade,the crystallite dimension of HA treated with nbutyl alcohol was reduced by two thirds,moreover,the particle aggregation phenomena was decreased obviously.
2005, 22(9): 980-983
Abstract:
Three N,N-dimethylpropyl tert-butylcalix[n] aryl acetoamides 3a~3c(n=4,6,8) were synthesized in moderate yields by treating ethyl tert-butylcalix[n] aryl acetates with N,N-dimethyl-1,3-diaminopropane,which were prepared by the alkylation of tert-butyicalix[n] arenes with ethyl chloroacetate in a system of K2CO3/KI/acetone.The extraction properties of these polydentated amide derivatives with octopus shape for metal cations were tested.Compounds 3a and 3c show especially selective extraction for Na+ and K+ respectively.
Three N,N-dimethylpropyl tert-butylcalix[n] aryl acetoamides 3a~3c(n=4,6,8) were synthesized in moderate yields by treating ethyl tert-butylcalix[n] aryl acetates with N,N-dimethyl-1,3-diaminopropane,which were prepared by the alkylation of tert-butyicalix[n] arenes with ethyl chloroacetate in a system of K2CO3/KI/acetone.The extraction properties of these polydentated amide derivatives with octopus shape for metal cations were tested.Compounds 3a and 3c show especially selective extraction for Na+ and K+ respectively.
2005, 22(9): 984-988
Abstract:
Silica-titania binaries and poly(butyl methacrylate)/silica-titania hybrid materials were synthesizedviathe sol-gel method.The structures of both the materials were characterized,respectively.It was found thatamorphous TiO2was dispersed in the network of SiO2,forming a stable and chemical homogeneous silica-titania binary material.The results of RAMAN,XRD and FESEMall indicate that the diameters of the parti-cles of silica-titania inorganic phase are around 15 nm(nano level).Poly(butyl methacrylate)/silica-titaniahybrid material is continuous and homogeneous with the introduction of a silane coupling agent.Thermogravimetric analysis showed that compared with that of pure PBMA,Tmax of the hybrid material hasshifted obviously from(258±3)℃ to(271±3)℃,indicating that the connection of the organic moleculeswith the inorganic network by chemical bonds can improve the heat resistance of the hybrid material.
Silica-titania binaries and poly(butyl methacrylate)/silica-titania hybrid materials were synthesizedviathe sol-gel method.The structures of both the materials were characterized,respectively.It was found thatamorphous TiO2was dispersed in the network of SiO2,forming a stable and chemical homogeneous silica-titania binary material.The results of RAMAN,XRD and FESEMall indicate that the diameters of the parti-cles of silica-titania inorganic phase are around 15 nm(nano level).Poly(butyl methacrylate)/silica-titaniahybrid material is continuous and homogeneous with the introduction of a silane coupling agent.Thermogravimetric analysis showed that compared with that of pure PBMA,Tmax of the hybrid material hasshifted obviously from(258±3)℃ to(271±3)℃,indicating that the connection of the organic moleculeswith the inorganic network by chemical bonds can improve the heat resistance of the hybrid material.
2005, 22(9): 989-992
Abstract:
Nine tris(substituted silylmethylene) tin pridinecarboxylates were synthesized by the reactions of bis{tris[(trimethysilyl)methy]tin} oxides with pridinecarboxylic acids,and their structures were charac-(terized) by means of IR,1H NMR,13C NMR,MS and elemental analysis.The preliminary bioassay results show that tris[(trimethysilyl)methy]tin pridinecarboxylates and tris[(ethyldmethysilyl)methy]tin 3-pridinecarboxylate have better miticical activity,the miticical activity of tris[(butyldimethysilyl)methy]tin 3-pridinecarboxylate is poor.
Nine tris(substituted silylmethylene) tin pridinecarboxylates were synthesized by the reactions of bis{tris[(trimethysilyl)methy]tin} oxides with pridinecarboxylic acids,and their structures were charac-(terized) by means of IR,1H NMR,13C NMR,MS and elemental analysis.The preliminary bioassay results show that tris[(trimethysilyl)methy]tin pridinecarboxylates and tris[(ethyldmethysilyl)methy]tin 3-pridinecarboxylate have better miticical activity,the miticical activity of tris[(butyldimethysilyl)methy]tin 3-pridinecarboxylate is poor.
2005, 22(9): 993-996
Abstract:
The present paper covers the electrochemical behavior of the interaction of Vitamin B12 with DNA at pH 4.87.After adding DNA in the Vitamin B12 solution,the reduction current of Vitamin B12 decreases.From the determination of the electrochemical parameters(charge transfer coefficient α and standard electron transfer rate constant ks) in the absence and presence of DNA,it was found that an electrochemical inactive supermolecular complex DNA-VB12 was formed.A series of equations was deduced for this kind of system.The equilibrium constant of this complex was calculated to be 1.6×105) mol/L).The decrease in peak current of VB12 is proportional to DNA concentration and it can be used to determine DNA concentration.
The present paper covers the electrochemical behavior of the interaction of Vitamin B12 with DNA at pH 4.87.After adding DNA in the Vitamin B12 solution,the reduction current of Vitamin B12 decreases.From the determination of the electrochemical parameters(charge transfer coefficient α and standard electron transfer rate constant ks) in the absence and presence of DNA,it was found that an electrochemical inactive supermolecular complex DNA-VB12 was formed.A series of equations was deduced for this kind of system.The equilibrium constant of this complex was calculated to be 1.6×105) mol/L).The decrease in peak current of VB12 is proportional to DNA concentration and it can be used to determine DNA concentration.
2005, 22(9): 997-1001
Abstract:
The promotion effects of N-donor ligands for catalytic oxidative carbonylation of methanol were studied.It was found that the base strength of ligands,the size of conjugated systems,the rigidity of skeletons and the hydrogen bonds between the ligands had remarkable influences on the calalytic performance for the oxidative carbonylation.The ligands with larger conjugated systems and rigid skeletons give better catalytic activities,and intermolecular hydrogen bonds between ligands greatly decrease promoting activities.For monodentate ligands without intermolecular hydrogen bonds,those with pKa 7 exhibit the best promoting activity.The mechanism of steric and electronic effects for the oxidative carbonylation of methanol in homogeneous system was discussed in detail.
The promotion effects of N-donor ligands for catalytic oxidative carbonylation of methanol were studied.It was found that the base strength of ligands,the size of conjugated systems,the rigidity of skeletons and the hydrogen bonds between the ligands had remarkable influences on the calalytic performance for the oxidative carbonylation.The ligands with larger conjugated systems and rigid skeletons give better catalytic activities,and intermolecular hydrogen bonds between ligands greatly decrease promoting activities.For monodentate ligands without intermolecular hydrogen bonds,those with pKa 7 exhibit the best promoting activity.The mechanism of steric and electronic effects for the oxidative carbonylation of methanol in homogeneous system was discussed in detail.
2005, 22(9): 1002-1006
Abstract:
The acid property of zirconium oxychloride was characterized by means of DTA and FT-IR spectra of pyridine absorbed on the surface. Its acid strength was estimated with Hammett indictor. With ketalization between cyclohexanone and 2, 3-butanediol as a probe reaction, the optimum conditions were obtained. ZrOCl2 catalytic activity in other ketalization was investigated and its catalytic activity was compared with those of other catalysts in ketalization. The results show that the catalyst has Broensted acid centers that could change the color of Hammett indictor (p-nitrophenylamine). The yield of cyclohexanone 2, 3-butanediol ketal is 96. 5% under the optimum conditions, and it shows excellent catalytic activity in other ketal synthesis. The catalyst could be recovered easily and the post-treatment was simple. No waste acid was discharged. The drawback brought by using conventional liquid inorganic acid to catalyze ketalization could be avoided. It is an environmental friendly catalyst to ketalization.
The acid property of zirconium oxychloride was characterized by means of DTA and FT-IR spectra of pyridine absorbed on the surface. Its acid strength was estimated with Hammett indictor. With ketalization between cyclohexanone and 2, 3-butanediol as a probe reaction, the optimum conditions were obtained. ZrOCl2 catalytic activity in other ketalization was investigated and its catalytic activity was compared with those of other catalysts in ketalization. The results show that the catalyst has Broensted acid centers that could change the color of Hammett indictor (p-nitrophenylamine). The yield of cyclohexanone 2, 3-butanediol ketal is 96. 5% under the optimum conditions, and it shows excellent catalytic activity in other ketal synthesis. The catalyst could be recovered easily and the post-treatment was simple. No waste acid was discharged. The drawback brought by using conventional liquid inorganic acid to catalyze ketalization could be avoided. It is an environmental friendly catalyst to ketalization.
2005, 22(9): 1007-1011
Abstract:
Sodium alginate has been widely used in a variety of biomedical applications.However,alginate itself has a very slow degradation rate,and its gels degrade in an uncontrollable manner,releasing high molecular weight strands that are difficult to drain from the body.In order to improve the biodegradability of alginate,commercially available high molecular weight alginate was oxidized with sodium periodate.The IR analysis confirmed the characteristic peak of aldehyde group in the oxidized alginate.Oxidized alginate fully degraded at physiological condition(37℃,pH=7.4 PBS) after 100 h incubation and the molecular weight reduced from 11.2×1044 g/mol.When small amounts of uronate groups were oxidized,the aqueous solution of the oxidized alginates still formed hydrogels in the presence of calcium ions in a manner similar to that of native sodium alginate.However,the compressive strengths of these hydrogels were lower than those of unmodified alginate and decreased quickly with incubation time.
Sodium alginate has been widely used in a variety of biomedical applications.However,alginate itself has a very slow degradation rate,and its gels degrade in an uncontrollable manner,releasing high molecular weight strands that are difficult to drain from the body.In order to improve the biodegradability of alginate,commercially available high molecular weight alginate was oxidized with sodium periodate.The IR analysis confirmed the characteristic peak of aldehyde group in the oxidized alginate.Oxidized alginate fully degraded at physiological condition(37℃,pH=7.4 PBS) after 100 h incubation and the molecular weight reduced from 11.2×1044 g/mol.When small amounts of uronate groups were oxidized,the aqueous solution of the oxidized alginates still formed hydrogels in the presence of calcium ions in a manner similar to that of native sodium alginate.However,the compressive strengths of these hydrogels were lower than those of unmodified alginate and decreased quickly with incubation time.
2005, 22(9): 1012-1016
Abstract:
The Adsorption capability of a novel amino-novolac copper templated resin(F44-34-M) for water-soluble dyes such as Acid Orange Ⅱ,Reactive Red Y-3B and Directed Sky Blue 5B were studied.The effects of pH value,temperature,time and the concentration of the dyes on the adsorption of the resin for the dyes were also studied.The results show that the adsorption capacities of the templated resin for the dyes are stronger than those of the non-templated resin.The adsorption fits the theory of liquid membrane diffusion by Boyd.The adsorption velocity of the resin for the dyes is fast and the apparent velocity constants should be between 0.012~0.042 min-1.The adsorption can be described by the Langmuir and Freundlich equations and the adsorption processes for the dyes are exothermic.Decolorization rate of the resin for simulated waste-water dyes exceeds 92%.
The Adsorption capability of a novel amino-novolac copper templated resin(F44-34-M) for water-soluble dyes such as Acid Orange Ⅱ,Reactive Red Y-3B and Directed Sky Blue 5B were studied.The effects of pH value,temperature,time and the concentration of the dyes on the adsorption of the resin for the dyes were also studied.The results show that the adsorption capacities of the templated resin for the dyes are stronger than those of the non-templated resin.The adsorption fits the theory of liquid membrane diffusion by Boyd.The adsorption velocity of the resin for the dyes is fast and the apparent velocity constants should be between 0.012~0.042 min-1.The adsorption can be described by the Langmuir and Freundlich equations and the adsorption processes for the dyes are exothermic.Decolorization rate of the resin for simulated waste-water dyes exceeds 92%.
2005, 22(9): 1017-1020
Abstract:
The rate-accelerating additives for living free radical polymerization of styrene in the presence of sodium nitrite and iron(Ⅱ) sulfate were studied.It was found that the styrene polymerization mediated with AIBN/NaNO2/FeSO4·7H2O was distinctly accelerated by the additive,such as diethylmalonate(DEM),acetylacetone(AAT),ethyl acetoacetic ester(AAE),or malonoitrile(MN).Among those additives,(malonoitrile)(MN) showed the best effect of rate enhancement and maintained the character of living free-radical polymerization while accelerating the rate of the polymerization.The conversion reached 80.0% within 5 h at 120℃ when n(MN):n(NaNO2):n(FeSO4·7H2O)=4:1:1 and [MN] equaled 0.312 mol/L.The polymerization rate was twenty times as fast as that of the polymerization without any additives.The molecular weight distribution was narrow,and the molecular weight was well controlled under 4×104,and the difference between the theoretical molecular weight and the experimental molecular weight was below 20%.With the increase of the conversion of monomer,the molecular weight of the polymer also increased linearly.The spectrum of 1H NMR show that MN didn't alter the structure of the polymer and only acted as an accelerator.
The rate-accelerating additives for living free radical polymerization of styrene in the presence of sodium nitrite and iron(Ⅱ) sulfate were studied.It was found that the styrene polymerization mediated with AIBN/NaNO2/FeSO4·7H2O was distinctly accelerated by the additive,such as diethylmalonate(DEM),acetylacetone(AAT),ethyl acetoacetic ester(AAE),or malonoitrile(MN).Among those additives,(malonoitrile)(MN) showed the best effect of rate enhancement and maintained the character of living free-radical polymerization while accelerating the rate of the polymerization.The conversion reached 80.0% within 5 h at 120℃ when n(MN):n(NaNO2):n(FeSO4·7H2O)=4:1:1 and [MN] equaled 0.312 mol/L.The polymerization rate was twenty times as fast as that of the polymerization without any additives.The molecular weight distribution was narrow,and the molecular weight was well controlled under 4×104,and the difference between the theoretical molecular weight and the experimental molecular weight was below 20%.With the increase of the conversion of monomer,the molecular weight of the polymer also increased linearly.The spectrum of 1H NMR show that MN didn't alter the structure of the polymer and only acted as an accelerator.
2005, 22(9): 1021-1023
Abstract:
Four new acylhydrazones containing carboxyl,3a~3d,were synthesized and their compositions and structures were characterized with elemental analysis, MS,IR and 1H NMR spectra.Their bacterio-static activities against staphylocus auteus,escherichia coil and bacillus subtilis were studied by Kirby-Bauer method.
Four new acylhydrazones containing carboxyl,3a~3d,were synthesized and their compositions and structures were characterized with elemental analysis, MS,IR and 1H NMR spectra.Their bacterio-static activities against staphylocus auteus,escherichia coil and bacillus subtilis were studied by Kirby-Bauer method.
2005, 22(9): 1024-1026
Abstract:
A novel room-temperature compression molding method combined with particulate leaching was developed to fabricate porous polyester scaffolds with the anatomical shape of the tissue or organ potentially applied in tissue engineering.Complicated-shaped scaffolds,such as auricle-like ones,were successfully fabricated from compression-molding putty-like mixture of concentrated poly(ε-caprolactone) solution and salt particulate in a mould with a complicated-shaped cavity at room temperature.The resultant porosity can reach over 90%.This room-temperature compression molding method is proven to be very convenient to fabricate three-dimensional porous scaffolds composed of biodegradable polymers.
A novel room-temperature compression molding method combined with particulate leaching was developed to fabricate porous polyester scaffolds with the anatomical shape of the tissue or organ potentially applied in tissue engineering.Complicated-shaped scaffolds,such as auricle-like ones,were successfully fabricated from compression-molding putty-like mixture of concentrated poly(ε-caprolactone) solution and salt particulate in a mould with a complicated-shaped cavity at room temperature.The resultant porosity can reach over 90%.This room-temperature compression molding method is proven to be very convenient to fabricate three-dimensional porous scaffolds composed of biodegradable polymers.
2005, 22(9): 1027-1029
Abstract:
2-Amino-5-methylbenzoic acid(1) was acylated with acyl chlorides,then heated together with acetic anhydride to give 2-phenyl or 2-benzyl-6-methylbenzoxazin-4-one(3a~3b),while compound 1 was reacted with propanoic anhydride or trifluoroacetic anhydride to give 2-ethyl or 2-trifluoromethyl-6-methylbenzoxazin-4-one(3c~3d) directly. Then,2-substituted 6-methylbenzoxazin-4-ones(3a~3d) were heated together with formamide to afford 2-substituted 6-methyl-4(3H)-quinazolinones(4a~4d),which were converted into the title compounds(5a~5d) via brominating with N-bromosuccinimide in the presence of (PhCOO)2.The structures of all the intermediates and final products were confirmed with ESI-MS,1H NMR and elemental analysis.
2-Amino-5-methylbenzoic acid(1) was acylated with acyl chlorides,then heated together with acetic anhydride to give 2-phenyl or 2-benzyl-6-methylbenzoxazin-4-one(3a~3b),while compound 1 was reacted with propanoic anhydride or trifluoroacetic anhydride to give 2-ethyl or 2-trifluoromethyl-6-methylbenzoxazin-4-one(3c~3d) directly. Then,2-substituted 6-methylbenzoxazin-4-ones(3a~3d) were heated together with formamide to afford 2-substituted 6-methyl-4(3H)-quinazolinones(4a~4d),which were converted into the title compounds(5a~5d) via brominating with N-bromosuccinimide in the presence of (PhCOO)2.The structures of all the intermediates and final products were confirmed with ESI-MS,1H NMR and elemental analysis.
2005, 22(9): 1030-1032
Abstract:
The crystal structure of cryptand L was determined via X-ray diffraction analysis.Four solid cryptates of cryptand(L) with M(Ⅲ) nitrates(M=Sm,Eu,Tb,Dy) were prepared and characterized by means of fluorescence spectroscopy.The fluorescence properties of those complexes show that all the cryptates have stronger luminescence intensity.That the complex of Eu(Ⅲ) has the strongest luminescence intensity(among) them shows that the cryptand's triplet state energy matches with the vibration energy level of Eu(Ⅲ).The difference between fluorescence intensities of L cryptates and other series of cryptates implies that the energy transfer from L is more effective in fluorescence and antenna when L has a more flexibility structure.
The crystal structure of cryptand L was determined via X-ray diffraction analysis.Four solid cryptates of cryptand(L) with M(Ⅲ) nitrates(M=Sm,Eu,Tb,Dy) were prepared and characterized by means of fluorescence spectroscopy.The fluorescence properties of those complexes show that all the cryptates have stronger luminescence intensity.That the complex of Eu(Ⅲ) has the strongest luminescence intensity(among) them shows that the cryptand's triplet state energy matches with the vibration energy level of Eu(Ⅲ).The difference between fluorescence intensities of L cryptates and other series of cryptates implies that the energy transfer from L is more effective in fluorescence and antenna when L has a more flexibility structure.
2005, 22(9): 1033-1035
Abstract:
In this work,the chemical modification of rice straw by epichlorohy(ECH) was carried out.The thermoplasticity of the modified straw was briefly investigated with toluene(10 mL) used as solvent,epichlorohy (ECH)(8 mL) as etherifying agent,and 50% NaOH(8 mL) as swelling agent and catalyst.The reaction was carried out for 6 h at 100℃,modified rice straw with WPG over 80% was gained.Influences of amounts of epichlorohy(ECH) and NaOH,reaction temperature and reaction time were studied for weight percent gained(WPG) of rice straw.FTIR,X-ray,DSC were used to characterize the structure of modified rice straw.The investigation showed that the crystalline component of modified rice straw decreased from 50% to 30%,and the glass transition temperature(Tg) of modified rice straw was 187.4℃.The results may offer a theoretical basis for potential application.
In this work,the chemical modification of rice straw by epichlorohy(ECH) was carried out.The thermoplasticity of the modified straw was briefly investigated with toluene(10 mL) used as solvent,epichlorohy (ECH)(8 mL) as etherifying agent,and 50% NaOH(8 mL) as swelling agent and catalyst.The reaction was carried out for 6 h at 100℃,modified rice straw with WPG over 80% was gained.Influences of amounts of epichlorohy(ECH) and NaOH,reaction temperature and reaction time were studied for weight percent gained(WPG) of rice straw.FTIR,X-ray,DSC were used to characterize the structure of modified rice straw.The investigation showed that the crystalline component of modified rice straw decreased from 50% to 30%,and the glass transition temperature(Tg) of modified rice straw was 187.4℃.The results may offer a theoretical basis for potential application.
2005, 22(9): 1036-1038
Abstract:
The present paper covers a novel method for the preparation of α-naphthylacetone via the addition-hydrolysis reaction of a 2-(α-naphthylmethyl)benzimidazolium salt with Grignard reagent.The IR spectrum,MS and 1H NMR of the title compound are consistent with those reported.This method provides a convenient and inexpensive access to the title compound.The mechanism for the addition-hydrolysis reaction of benzimi-dazolium salt with Grignard reagent and the effects of reaction conditions on the yield are discussed.
The present paper covers a novel method for the preparation of α-naphthylacetone via the addition-hydrolysis reaction of a 2-(α-naphthylmethyl)benzimidazolium salt with Grignard reagent.The IR spectrum,MS and 1H NMR of the title compound are consistent with those reported.This method provides a convenient and inexpensive access to the title compound.The mechanism for the addition-hydrolysis reaction of benzimi-dazolium salt with Grignard reagent and the effects of reaction conditions on the yield are discussed.
2005, 22(9): 1039-1041
Abstract:
One pyridine ring was introduced into the basic structure of stilbene in place of one of the benzene rings for the purpose of evaluating the activity change.Started from methoxyl substituted chloromethylpyridine,five new polyhydroxy-azastilbene-2-nitrogen derivatives(4a~4e) with (E)-isomer were synthesized via Arbusow reaction,Wittig-Horner reaction and demethalytion in a yield of 30%~34% as the main products.Their structures were characterized by IR,MS and 1H NMR.
One pyridine ring was introduced into the basic structure of stilbene in place of one of the benzene rings for the purpose of evaluating the activity change.Started from methoxyl substituted chloromethylpyridine,five new polyhydroxy-azastilbene-2-nitrogen derivatives(4a~4e) with (E)-isomer were synthesized via Arbusow reaction,Wittig-Horner reaction and demethalytion in a yield of 30%~34% as the main products.Their structures were characterized by IR,MS and 1H NMR.
2005, 22(9): 1042-1044
Abstract:
In view of the importance of β-lactams in the pharmaceutic research field, a series of pyrazoloderi-vatives of monocyclic β-lactams 2a~2h was prepared from the schiff base 1a~1h reactions with phthalo-ylglycyl chloride in the presence of triethylamine via [2+2] cycloaddition.The structures and configurations of the prepared new monocyclic β-lactams were confirmed by 1H NMR, 1H-1H COSY,NOESY,HMBC,HMQC methods.At 75~85℃,compounds 2a~2h were obtained in yields of 19%~50% respectively.
In view of the importance of β-lactams in the pharmaceutic research field, a series of pyrazoloderi-vatives of monocyclic β-lactams 2a~2h was prepared from the schiff base 1a~1h reactions with phthalo-ylglycyl chloride in the presence of triethylamine via [2+2] cycloaddition.The structures and configurations of the prepared new monocyclic β-lactams were confirmed by 1H NMR, 1H-1H COSY,NOESY,HMBC,HMQC methods.At 75~85℃,compounds 2a~2h were obtained in yields of 19%~50% respectively.
