Login In
2009 Volume 26 Issue 2
2009, 26(2): 125-129
Abstract:
A new stationary phase was synthesized for chiral-ligand-exchange chromatography from a reaction of L-isoleucine with monodispersed poly(glycidylmethacrylate-co-ethylenedimethacrylate) particles.The enantiomeric resolutions of 12 DL-amino acids were achieved on the synthesized chiral ligand exchange chromatographic stationary phase with 0.2 mol/L NaAc and 0.1 mmol/L Cu(Ac)2 aqueous solution as mobile phase and detection wavelength set at 254 nm.The enantioselectivities of the DL-amino acids separated were found to be in a range of 1.23~2.33.The effects of the chromatographic conditions,such as pH and temperature of column and flow rate of eluent,on the enantiomeric resolution of the DL-amino acids were studied.The thermodynamics in chromatographic separation were discussed.
A new stationary phase was synthesized for chiral-ligand-exchange chromatography from a reaction of L-isoleucine with monodispersed poly(glycidylmethacrylate-co-ethylenedimethacrylate) particles.The enantiomeric resolutions of 12 DL-amino acids were achieved on the synthesized chiral ligand exchange chromatographic stationary phase with 0.2 mol/L NaAc and 0.1 mmol/L Cu(Ac)2 aqueous solution as mobile phase and detection wavelength set at 254 nm.The enantioselectivities of the DL-amino acids separated were found to be in a range of 1.23~2.33.The effects of the chromatographic conditions,such as pH and temperature of column and flow rate of eluent,on the enantiomeric resolution of the DL-amino acids were studied.The thermodynamics in chromatographic separation were discussed.
2009, 26(2): 130-134
Abstract:
Several aromatic aldehydes and sodium bisulfite were mixed to prepare hydroxyl sulfonates,which were added to o-phenylenediamine or substituted o-phenylenediamine in refluxing ethanol to afford 2-substi-tuted benzimidazoles through oxidation by air directly.One of the fifteen synthesized compounds,2-(4-chlorophyenyl)-6-methoxyl-1H-benzimidazole has not been reported.All the compounds were identified by IR,1H NMR spectra and elemental analysis.The method is simple,mild,eco-friendly and requires no catalyst.
Several aromatic aldehydes and sodium bisulfite were mixed to prepare hydroxyl sulfonates,which were added to o-phenylenediamine or substituted o-phenylenediamine in refluxing ethanol to afford 2-substi-tuted benzimidazoles through oxidation by air directly.One of the fifteen synthesized compounds,2-(4-chlorophyenyl)-6-methoxyl-1H-benzimidazole has not been reported.All the compounds were identified by IR,1H NMR spectra and elemental analysis.The method is simple,mild,eco-friendly and requires no catalyst.
2009, 26(2): 135-139
Abstract:
By adjusting the proportion of Ketjen black EC-600JD(KB) and Black pearls 2000(BP),the optimal pore structure of the cathode microporous diffusive layer of an air-breathing direct methanol fuel cell(DMFC) can be obtained,which improves the mass transfer of oxygen and avoids the water flooding within the cathode.The experimental results show that the addition of BP in the cathode diffusive layer has a significant influence on DMFC's performance.When the mass ratio of KB and BP is ca.9:1,an air-breathing DMFC at a temperature of 25 ℃ exhibits the highest power density of 20.8×10-3 W/cm2 with the best stability.It is believed that the enhanced power density and improved stability of the DMFC could be ascribed to an improvement in cathode porous structure due to the addition of small amounts of BP.
By adjusting the proportion of Ketjen black EC-600JD(KB) and Black pearls 2000(BP),the optimal pore structure of the cathode microporous diffusive layer of an air-breathing direct methanol fuel cell(DMFC) can be obtained,which improves the mass transfer of oxygen and avoids the water flooding within the cathode.The experimental results show that the addition of BP in the cathode diffusive layer has a significant influence on DMFC's performance.When the mass ratio of KB and BP is ca.9:1,an air-breathing DMFC at a temperature of 25 ℃ exhibits the highest power density of 20.8×10-3 W/cm2 with the best stability.It is believed that the enhanced power density and improved stability of the DMFC could be ascribed to an improvement in cathode porous structure due to the addition of small amounts of BP.
2009, 26(2): 140-143
Abstract:
Organotin(Ⅳ) complex {[(n-C4H9)2Sn(0.5·O2CCH2C12H8N)(0.5·C2H5O)]2O}2·(C12H8NH) was synthesized by the reaction of n-dibutyltin oxide with(9-carbazoly)-acetic acid.The complex was characterized by elemental analysis,IR and 1H NMR.The crystal structure was determined by X-ray single crystal diffraction.The crystal belongs to monoclinic,with space group C2/c with a=2.797 5(13) nm,b=2.153 4(10) nm,c=1.515 4(7) nm,β=118.759(6)°,V=8.003(7) nm3,Z=4,μ=1.285 mm-1,Dc=1.386 g/cm3,F(000)=3 408,R=0.057 1,wR=0.136 2,GOF=1.005.The complex is a centrosymmetric structure mode with a four-member central endo-cyclic Sn2O2 unit in which two bridged oxygen atoms both connect with an exo-cyclic tin atom.The endo-cyclic tin atoms and the exo-cyclic tin atoms are all five-coordination and have a coordination geometry of a distorted trigonal bipyramid.This complex was tested in vitro against human tumour cell lines,MCF-7 and WiDr,and displayed high activity.
Organotin(Ⅳ) complex {[(n-C4H9)2Sn(0.5·O2CCH2C12H8N)(0.5·C2H5O)]2O}2·(C12H8NH) was synthesized by the reaction of n-dibutyltin oxide with(9-carbazoly)-acetic acid.The complex was characterized by elemental analysis,IR and 1H NMR.The crystal structure was determined by X-ray single crystal diffraction.The crystal belongs to monoclinic,with space group C2/c with a=2.797 5(13) nm,b=2.153 4(10) nm,c=1.515 4(7) nm,β=118.759(6)°,V=8.003(7) nm3,Z=4,μ=1.285 mm-1,Dc=1.386 g/cm3,F(000)=3 408,R=0.057 1,wR=0.136 2,GOF=1.005.The complex is a centrosymmetric structure mode with a four-member central endo-cyclic Sn2O2 unit in which two bridged oxygen atoms both connect with an exo-cyclic tin atom.The endo-cyclic tin atoms and the exo-cyclic tin atoms are all five-coordination and have a coordination geometry of a distorted trigonal bipyramid.This complex was tested in vitro against human tumour cell lines,MCF-7 and WiDr,and displayed high activity.
2009, 26(2): 144-148
Abstract:
A Keggin-type polyoxometalate [Mn(phen)3]2(H3O)[BW12O40]·2H2O was prepared under hydrothermal conditions,and characterized by elemental analysis,IR,TG and single crystal X-ray diffraction analysis.The title compound crystallized in a Monoclinic system,space group C2/c,a=2.728 5(3) nm,b=2.506 0(3) nm,c=1.633 66(18) nm,β=104.911(2)°,V=10.794(2) nm3,Z=4,R1=0.078 4,wR2=0.199 9.The structure unit of the title compound consists of a Keggin-type heteropolyanion [BW12O40]5-,two coordinated cations [Mn(phen)3]2+,one proton and two lattice water molecules.The molecules of the title compound are extended into a 3-D supramolecular array through π-π stacking contacts.
A Keggin-type polyoxometalate [Mn(phen)3]2(H3O)[BW12O40]·2H2O was prepared under hydrothermal conditions,and characterized by elemental analysis,IR,TG and single crystal X-ray diffraction analysis.The title compound crystallized in a Monoclinic system,space group C2/c,a=2.728 5(3) nm,b=2.506 0(3) nm,c=1.633 66(18) nm,β=104.911(2)°,V=10.794(2) nm3,Z=4,R1=0.078 4,wR2=0.199 9.The structure unit of the title compound consists of a Keggin-type heteropolyanion [BW12O40]5-,two coordinated cations [Mn(phen)3]2+,one proton and two lattice water molecules.The molecules of the title compound are extended into a 3-D supramolecular array through π-π stacking contacts.
2009, 26(2): 149-153
Abstract:
A green sand-fixing agent of water-borne polymer,poly(vinyl acetate-butyl acrylate latex)(P(VAc-BA)),was synthesized and characterized.The influences of protective colloid,the amount of emulsifier and the emulsifier ratio m(SDBS)/m(Tween-60) on emulsion properties were discussed.With the sand soil as research object,the water retention,compressive strength,the tolerance of high temperature and water resistance of the sand-fixing agent were studied preliminarily.The results showed that when mass content of the protective colloid was 3%,mass content of the total emulsifier was 4% and the inner ratio 1:3,the visco-sity of the product was 155.40 mPa·s,and the product had a good thermal stability between 0~220 ℃ and a good sand fixation performance for practical application.
A green sand-fixing agent of water-borne polymer,poly(vinyl acetate-butyl acrylate latex)(P(VAc-BA)),was synthesized and characterized.The influences of protective colloid,the amount of emulsifier and the emulsifier ratio m(SDBS)/m(Tween-60) on emulsion properties were discussed.With the sand soil as research object,the water retention,compressive strength,the tolerance of high temperature and water resistance of the sand-fixing agent were studied preliminarily.The results showed that when mass content of the protective colloid was 3%,mass content of the total emulsifier was 4% and the inner ratio 1:3,the visco-sity of the product was 155.40 mPa·s,and the product had a good thermal stability between 0~220 ℃ and a good sand fixation performance for practical application.
2009, 26(2): 154-158
Abstract:
Emulsion containing 1.52% mass fraction glutathione was prepared.Glutathione was coated on the surface of fibers via oil process,and the chemical properties of the cellulose acetate tow were modified.We analyzed the physical properties and surface morphology of the modified cellulose acetate tow.The contents of the common components and free radicals in cigarette smoke were also analyzed.The results showed that the manufacturing properties of the modified cellulose acetate tow were similar to that of common tow.The tar content in main smoke was reduced by 1.08 mg.The particulate-phase and gas-phase free radicals in the smoke can be reduced by up to 21.34% and 25.07%.
Emulsion containing 1.52% mass fraction glutathione was prepared.Glutathione was coated on the surface of fibers via oil process,and the chemical properties of the cellulose acetate tow were modified.We analyzed the physical properties and surface morphology of the modified cellulose acetate tow.The contents of the common components and free radicals in cigarette smoke were also analyzed.The results showed that the manufacturing properties of the modified cellulose acetate tow were similar to that of common tow.The tar content in main smoke was reduced by 1.08 mg.The particulate-phase and gas-phase free radicals in the smoke can be reduced by up to 21.34% and 25.07%.
2009, 26(2): 159-162
Abstract:
Hyperbranched polyurethane was successfully synthesized by AA'+bB2 approach and it could be used as hot melt adhesives.Excessive 2,4-toluylene diisocyanate(TDI) was used to react with polycarbona-tediols(PCDL) to obtain isocyanate end-capped oligomeric A2.Then the bB2 monomer,diethanolamine(DEOA) was added at 0 ℃ to form the AB2 intermediate.Further self-condensation of this AB2 intermediate led to hyperbranched polyurethane(HPU) with long chains between the branching points at a higher temperature.The structure of the product was characterized by FTIR,13C NMR and GPC.The results show that the degree of branching(DB) of the polymer was up to 0.75 when the reaction was conducted at 55 ℃ for 20 h,and the weight-average molecular mass(MW) was 7.0×103.The thermogravimetric analysis(TGA) and tensile test were also conducted.The degradation temperature of the product was up to 200 ℃.The adhesive shear strength of the product increased with increasing the length of the aliphatic chains,with the highest value of 6.5 MPa.
Hyperbranched polyurethane was successfully synthesized by AA'+bB2 approach and it could be used as hot melt adhesives.Excessive 2,4-toluylene diisocyanate(TDI) was used to react with polycarbona-tediols(PCDL) to obtain isocyanate end-capped oligomeric A2.Then the bB2 monomer,diethanolamine(DEOA) was added at 0 ℃ to form the AB2 intermediate.Further self-condensation of this AB2 intermediate led to hyperbranched polyurethane(HPU) with long chains between the branching points at a higher temperature.The structure of the product was characterized by FTIR,13C NMR and GPC.The results show that the degree of branching(DB) of the polymer was up to 0.75 when the reaction was conducted at 55 ℃ for 20 h,and the weight-average molecular mass(MW) was 7.0×103.The thermogravimetric analysis(TGA) and tensile test were also conducted.The degradation temperature of the product was up to 200 ℃.The adhesive shear strength of the product increased with increasing the length of the aliphatic chains,with the highest value of 6.5 MPa.
2009, 26(2): 163-167
Abstract:
Red light emitting conjugated copolymers derived from 9,9-dioctylfluorene(DOF) and 4,7-dithien-2-yl-2,1,3-benzoselenadiazole(BTSe) were synthesized via palladium-catalyzed Suzuki coupling reaction with x(BTSe) ranging from 0.1% to 35%.Polyfluorene fluorescence was quenched completely at BTSe content as low as 0.5% in the solid film.Devices based on these copolymers emitted red light at x(BTSe) from 0.1% to 35% in the copolymer,and the electroluminescent(EL) emission peaks of the devices with the copolymers red-shifted from 669 nm to 727 nm.The highest external quantum efficiency of 1.24% and brightness of 83 cd/m2 were obtained for the device from the copolymer with x(BTSe) of 0.1%.
Red light emitting conjugated copolymers derived from 9,9-dioctylfluorene(DOF) and 4,7-dithien-2-yl-2,1,3-benzoselenadiazole(BTSe) were synthesized via palladium-catalyzed Suzuki coupling reaction with x(BTSe) ranging from 0.1% to 35%.Polyfluorene fluorescence was quenched completely at BTSe content as low as 0.5% in the solid film.Devices based on these copolymers emitted red light at x(BTSe) from 0.1% to 35% in the copolymer,and the electroluminescent(EL) emission peaks of the devices with the copolymers red-shifted from 669 nm to 727 nm.The highest external quantum efficiency of 1.24% and brightness of 83 cd/m2 were obtained for the device from the copolymer with x(BTSe) of 0.1%.
2009, 26(2): 168-172
Abstract:
Ti-HMS and Ti/W-HMS molecular sieves were synthesized by varying the ratio of n(Si)/n(Ti) and n(Si)/n(W),and were used for the NH3-TPD analysis.The acidity of the molecular sieve is the largest when n(Si):n(Ti)=30:1,n(Si):n(W)=400:1.Different HMS were used for the oxidation of benzyl alcohol to benzyl aldehyde with 30% hydrogen peroxide solution as the oxidizing agent without any organic solvent and phase transfer catalyst.The results show that benzyl alcohol can be selectivity oxidized to benzyl aldehyde by Ti/W-HMS molecular sieves.The activity and selectivity of catalyst can be improved with increasing the acidity and acid strength.With Ti(30)/W(400)-HMS as catalyst,at n(alcohol):n(hydrogen peroxide)=1:2,ω(catalyst)=4%,and the reaction time 5 h,the conversion of benzyl alcohol and the selectivity of benzyl aldehyde reached to 72.6% and 96.9%,respectively.The conversion of benzyl alcohol and the selectivity of benzyl aldehyde reached to 63.2% and 89.1%,respectively,after catalyst was used for four times.
Ti-HMS and Ti/W-HMS molecular sieves were synthesized by varying the ratio of n(Si)/n(Ti) and n(Si)/n(W),and were used for the NH3-TPD analysis.The acidity of the molecular sieve is the largest when n(Si):n(Ti)=30:1,n(Si):n(W)=400:1.Different HMS were used for the oxidation of benzyl alcohol to benzyl aldehyde with 30% hydrogen peroxide solution as the oxidizing agent without any organic solvent and phase transfer catalyst.The results show that benzyl alcohol can be selectivity oxidized to benzyl aldehyde by Ti/W-HMS molecular sieves.The activity and selectivity of catalyst can be improved with increasing the acidity and acid strength.With Ti(30)/W(400)-HMS as catalyst,at n(alcohol):n(hydrogen peroxide)=1:2,ω(catalyst)=4%,and the reaction time 5 h,the conversion of benzyl alcohol and the selectivity of benzyl aldehyde reached to 72.6% and 96.9%,respectively.The conversion of benzyl alcohol and the selectivity of benzyl aldehyde reached to 63.2% and 89.1%,respectively,after catalyst was used for four times.
2009, 26(2): 173-177
Abstract:
The nitration of toluene in NO2/air catalyzed by ionic liquid was investigated.The reactions were carried out first at-10~0 ℃ and then at 25 ℃ for 20 h in the presence of slight excess of NO2(mole ratio of toluene to NO2 was about 1:1.4),and moderate yield and good selectivity were gained.The best result was obtained in the presence of [SO3H(CH2)4Py]HSO4,the mole ratio of which to toluene was 0.15,and the yield of mono-nitrotoluene was 77% with ortho/para=1.27.The ILs could be reused for four times with good catalytic activity and para-selectivity.
The nitration of toluene in NO2/air catalyzed by ionic liquid was investigated.The reactions were carried out first at-10~0 ℃ and then at 25 ℃ for 20 h in the presence of slight excess of NO2(mole ratio of toluene to NO2 was about 1:1.4),and moderate yield and good selectivity were gained.The best result was obtained in the presence of [SO3H(CH2)4Py]HSO4,the mole ratio of which to toluene was 0.15,and the yield of mono-nitrotoluene was 77% with ortho/para=1.27.The ILs could be reused for four times with good catalytic activity and para-selectivity.
2009, 26(2): 178-181
Abstract:
A new synthetic procedure was designed for the preparation of omeprazole.A one-pot method was performed for the oxidation of 2,3,5-trimethylpyridine and the nitration of 2,3,5-dimethylpyridine-N-oxide to get 2,3,5-dimethyl-4-nitropyridine-N-oxide,which was directly chlorinated with trichloroisocyanuric acid to provide the key intermediate 2-chloromethyl-3,5-dimethyl-4-nitropyridine-N-oxide.The chloromethylnitropyridine was treated with 2-mercapto-5-methoxybenzimidazole in the presence of excess sodium methoxide to simultaneously carry out the condensation and the methoxylation to give 5-methoxy-2-[(4-methoxy-3,5-dimethylpyridinyl-N-oxide)-methylthio]-1H-benzimidazole,from which omeprazole was finally obtained via the deoxidization with phosphorus trichloride and the oxidation with sodium perborate in an overall yield of 48.7%.The structures of the intermediates and omeprazole were confirmed by 1H NMR and MS.
A new synthetic procedure was designed for the preparation of omeprazole.A one-pot method was performed for the oxidation of 2,3,5-trimethylpyridine and the nitration of 2,3,5-dimethylpyridine-N-oxide to get 2,3,5-dimethyl-4-nitropyridine-N-oxide,which was directly chlorinated with trichloroisocyanuric acid to provide the key intermediate 2-chloromethyl-3,5-dimethyl-4-nitropyridine-N-oxide.The chloromethylnitropyridine was treated with 2-mercapto-5-methoxybenzimidazole in the presence of excess sodium methoxide to simultaneously carry out the condensation and the methoxylation to give 5-methoxy-2-[(4-methoxy-3,5-dimethylpyridinyl-N-oxide)-methylthio]-1H-benzimidazole,from which omeprazole was finally obtained via the deoxidization with phosphorus trichloride and the oxidation with sodium perborate in an overall yield of 48.7%.The structures of the intermediates and omeprazole were confirmed by 1H NMR and MS.
2009, 26(2): 182-186
Abstract:
Solid acid catalysts loaded on bentonite were prepared through anhydrous impregnation,and acetylsalicylate synthesis was used as a probe to inspect the influence of the preparation conditions of the catalysts and reaction conditions of acetylsalicylate synthesis on the catalytic properties.The catalysts were characterized by XRD,DTA,and iconic acid test.The result showed that the solid acid catalysts had the best catalytic capability after soaked in 10% HCl for overnight,loaded with 5.0 m mol/g ZnCl2 and 4.0 mmol/g CuCl2,and baked at a temperature of 550 ℃ for 3 h.And the preparation conditions of acetylsalicylate synthesis were as follows:the optimum temperature was 80~90 ℃;the optimum time was 1 h;the ratio of salicylic to acetic acid was 1:2,and the quantity of solid acid was 5% that of salicylic acid.Under these conditions,the yield of acetylsalicylate reached 96.6%,and the solid acid catalysts can replace sulfuric acid and can be reused.
Solid acid catalysts loaded on bentonite were prepared through anhydrous impregnation,and acetylsalicylate synthesis was used as a probe to inspect the influence of the preparation conditions of the catalysts and reaction conditions of acetylsalicylate synthesis on the catalytic properties.The catalysts were characterized by XRD,DTA,and iconic acid test.The result showed that the solid acid catalysts had the best catalytic capability after soaked in 10% HCl for overnight,loaded with 5.0 m mol/g ZnCl2 and 4.0 mmol/g CuCl2,and baked at a temperature of 550 ℃ for 3 h.And the preparation conditions of acetylsalicylate synthesis were as follows:the optimum temperature was 80~90 ℃;the optimum time was 1 h;the ratio of salicylic to acetic acid was 1:2,and the quantity of solid acid was 5% that of salicylic acid.Under these conditions,the yield of acetylsalicylate reached 96.6%,and the solid acid catalysts can replace sulfuric acid and can be reused.
2009, 26(2): 187-192
Abstract:
Bamboo was liquefied in ethylene glycol in the presence of sulfuric acid as catalyst,and realtime IR was used to detect the reaction during the whole experiment.The intensities of the bands at 1 720 cm-1 and 1 124 cm-1 strengthened,and that at 3 400 cm-1 weakened with the liquefaction time.The IR results were analysed in detail to describe the degradation and decomposition of bamboo,and the product was separated into several parts which were analysed by GC-MS.It indicated that the cellulose was degraded completely to pentanoic acid ethyl ester,2(3H)-furanone,(acetyloxy)dihydro-5-methyl,and lignin phenylpropane units were also decomposed to hydroxylic,carbnoxylic and aromatic derivatives,and these reactive intermediates could be polymerized to form insoluble residues.
Bamboo was liquefied in ethylene glycol in the presence of sulfuric acid as catalyst,and realtime IR was used to detect the reaction during the whole experiment.The intensities of the bands at 1 720 cm-1 and 1 124 cm-1 strengthened,and that at 3 400 cm-1 weakened with the liquefaction time.The IR results were analysed in detail to describe the degradation and decomposition of bamboo,and the product was separated into several parts which were analysed by GC-MS.It indicated that the cellulose was degraded completely to pentanoic acid ethyl ester,2(3H)-furanone,(acetyloxy)dihydro-5-methyl,and lignin phenylpropane units were also decomposed to hydroxylic,carbnoxylic and aromatic derivatives,and these reactive intermediates could be polymerized to form insoluble residues.
2009, 26(2): 193-197
Abstract:
Hydroxypropyl-chitsoan(HCS) with a substitution degree of 0.46 was prepared.Hydroxypropyl-chitosan nanospheres with the particle size of 100~300 nm were formed when hydroxypropyl-chitosan water solution reacts with sodium polyphosphate based on ion gel method.TEM micrograph reveals that the morpho-logy of hydroxypropyl-chitosan nanospheres was regular.Bovine Serum Albumin(BSA) was taken as the typical drug to determine the controlled release in vitro.The result suggests that the highest encapsulation efficiency and load of BSA reached to 86% and 46% respectively.The HCS nanospheres released 28% of BSA in average within 2 h,and it continuously release the entrapped protein,but with a slower rate.
Hydroxypropyl-chitsoan(HCS) with a substitution degree of 0.46 was prepared.Hydroxypropyl-chitosan nanospheres with the particle size of 100~300 nm were formed when hydroxypropyl-chitosan water solution reacts with sodium polyphosphate based on ion gel method.TEM micrograph reveals that the morpho-logy of hydroxypropyl-chitosan nanospheres was regular.Bovine Serum Albumin(BSA) was taken as the typical drug to determine the controlled release in vitro.The result suggests that the highest encapsulation efficiency and load of BSA reached to 86% and 46% respectively.The HCS nanospheres released 28% of BSA in average within 2 h,and it continuously release the entrapped protein,but with a slower rate.
2009, 26(2): 198-201
Abstract:
SnO2 nanoparticles have been successfully prepared from SnCl4 and NH3·H2O aqueous solution by hydrothermal method,and modified with γ-aminopropyl triethoxysilane(KH-550).The product was characterized with X-ray powder diffraction(XRD),transmission electron microscopy(TEM),nano-size/Zeta potential analyzer and elemental analysis.The results show that SnO2 nanoparticles are all tetragonal-rutile SnO2,the homogeneity of the modified SnO2 nanoparticles was improved with a narrow grain size distribution of 8~20 nm,and the particles can be dispersed stably in the system.
SnO2 nanoparticles have been successfully prepared from SnCl4 and NH3·H2O aqueous solution by hydrothermal method,and modified with γ-aminopropyl triethoxysilane(KH-550).The product was characterized with X-ray powder diffraction(XRD),transmission electron microscopy(TEM),nano-size/Zeta potential analyzer and elemental analysis.The results show that SnO2 nanoparticles are all tetragonal-rutile SnO2,the homogeneity of the modified SnO2 nanoparticles was improved with a narrow grain size distribution of 8~20 nm,and the particles can be dispersed stably in the system.
2009, 26(2): 202-205
Abstract:
Fe nanoparticles were prepared by reducing Fe2+ salt in an ethanol solution with NaBH4 in the presence of 2 Ethy hexanoic acid as a surfactant.The structure,morphology and thermal properties of the iron nanoparticles were investigated by means of X-ray diffraction(XRD),transmission electron microscopy(TEM),oxygen bomb calorimeter and themogravimetry(TG).The results showed that the crystal are body-centered-cubic,the particles are spherical with an average size of approximate 100 nm,and there is conglutination among the particles.The thermal property studies indicated that the mass of Fe increased from 22% to 28%,before and after using surfactant in a temperature range of 25～600 ℃,which showed that the anti-oxidation properties was improved distinctly after using surfactant.When the amount of Fe in Kerosene was less than 1%(mass ratio),the combustion heat value of the Kerosene would be enhanced and the maximum was approximately 234.08 J/g.
Fe nanoparticles were prepared by reducing Fe2+ salt in an ethanol solution with NaBH4 in the presence of 2 Ethy hexanoic acid as a surfactant.The structure,morphology and thermal properties of the iron nanoparticles were investigated by means of X-ray diffraction(XRD),transmission electron microscopy(TEM),oxygen bomb calorimeter and themogravimetry(TG).The results showed that the crystal are body-centered-cubic,the particles are spherical with an average size of approximate 100 nm,and there is conglutination among the particles.The thermal property studies indicated that the mass of Fe increased from 22% to 28%,before and after using surfactant in a temperature range of 25～600 ℃,which showed that the anti-oxidation properties was improved distinctly after using surfactant.When the amount of Fe in Kerosene was less than 1%(mass ratio),the combustion heat value of the Kerosene would be enhanced and the maximum was approximately 234.08 J/g.
2009, 26(2): 206-209
Abstract:
A novel phosphorus,sulfur and nitrogen containing intumscent flame retardant(IFR),diethoxy-acrylamide methoxy thiophosphate(DAMT),was synthesized by reacting N-hydroxymethyl-acrylamide with diethoxythiophosphoryl chloride.DAMT was characterized by elemental analysis,FTIR,1H NMR,and MS.The structure of DAMT was confirmed.The yield of DAMT was 80% when the molar ratio of acid capturing agent triethylamine to N-hydroxymethyl-acrylamide was 1:1,and the mass fraction of the catalyst CuCl was 1% of N-hydroxymethyl-acrylamide.The optimized reaction temperature ranged from 0 ℃ to 5 ℃.The limiting oxygen index(LOI) value reached 27% when the mass fraction of DAMT in the DAMT-acrylonitrile copolymer was 20%.The SEM micrographs of the char residue of the flame retarded copolymer revealed that the surface of the char residue was bubbly structured,and the cross section was honeycomb structure,indicating DAMT was a intumescent flame retardant.
A novel phosphorus,sulfur and nitrogen containing intumscent flame retardant(IFR),diethoxy-acrylamide methoxy thiophosphate(DAMT),was synthesized by reacting N-hydroxymethyl-acrylamide with diethoxythiophosphoryl chloride.DAMT was characterized by elemental analysis,FTIR,1H NMR,and MS.The structure of DAMT was confirmed.The yield of DAMT was 80% when the molar ratio of acid capturing agent triethylamine to N-hydroxymethyl-acrylamide was 1:1,and the mass fraction of the catalyst CuCl was 1% of N-hydroxymethyl-acrylamide.The optimized reaction temperature ranged from 0 ℃ to 5 ℃.The limiting oxygen index(LOI) value reached 27% when the mass fraction of DAMT in the DAMT-acrylonitrile copolymer was 20%.The SEM micrographs of the char residue of the flame retarded copolymer revealed that the surface of the char residue was bubbly structured,and the cross section was honeycomb structure,indicating DAMT was a intumescent flame retardant.
2009, 26(2): 210-213
Abstract:
Silicate glass powder was prepared from SiO2,Al2O3,CaF2,AlF3,NaAlF4 and AlPO4 under different fusing and cooling conditions.Environmental scanning electron microscopy(ESEM) was used to study the effect of silicate droplets in the glass powder on the mechanical properties of the glass ionomer cement(GIC).When the fusing mixture was cooled rapidly,the glass powder became phase separated and the silicate droplets were produced,which were the active phase in the setting reaction of the GIC and were composed of CaF2.When the fusing temperature was too low or the fusing time too short,the droplets were not produced completely.In contrast,the droplets were very small and easy to separate from the matrix.Two cases of both will result in low compressive strength of the GIC.To obtain GIC with good mechanical property,the glass powder must be cooled rapidly at 1 200 ℃ for 2 h.
Silicate glass powder was prepared from SiO2,Al2O3,CaF2,AlF3,NaAlF4 and AlPO4 under different fusing and cooling conditions.Environmental scanning electron microscopy(ESEM) was used to study the effect of silicate droplets in the glass powder on the mechanical properties of the glass ionomer cement(GIC).When the fusing mixture was cooled rapidly,the glass powder became phase separated and the silicate droplets were produced,which were the active phase in the setting reaction of the GIC and were composed of CaF2.When the fusing temperature was too low or the fusing time too short,the droplets were not produced completely.In contrast,the droplets were very small and easy to separate from the matrix.Two cases of both will result in low compressive strength of the GIC.To obtain GIC with good mechanical property,the glass powder must be cooled rapidly at 1 200 ℃ for 2 h.
2009, 26(2): 214-218
Abstract:
An oscillating reaction system was composed of BrO3--Mn2+-H2SO4-Acetone and the glucose substrate.The reaction was conducted at a constant temperature.The results show that the solution color changed between pink and uncolored alternately.The oscillating wave is typical.The apparent activation energy of the reaction was 80.38 kJ/mol at reduced stage,and 70.95 kJ/mol at oscillating stage.The concentration range of the reactants was established.The product of Br2 was confirmed during the oscillating reaction.The effects of temperature,reactant concentration,Cl- ,Br- ,I- ,on oscillating reaction were also discussed and the concentration of Cr(Ⅵ) was determined in the oscillating reaction system with satisfied results.
An oscillating reaction system was composed of BrO3--Mn2+-H2SO4-Acetone and the glucose substrate.The reaction was conducted at a constant temperature.The results show that the solution color changed between pink and uncolored alternately.The oscillating wave is typical.The apparent activation energy of the reaction was 80.38 kJ/mol at reduced stage,and 70.95 kJ/mol at oscillating stage.The concentration range of the reactants was established.The product of Br2 was confirmed during the oscillating reaction.The effects of temperature,reactant concentration,Cl- ,Br- ,I- ,on oscillating reaction were also discussed and the concentration of Cr(Ⅵ) was determined in the oscillating reaction system with satisfied results.
2009, 26(2): 219-223
Abstract:
The salicylic acid modified polystyrene was prepared to study adsorption properties toward Pb2+ and Cu2+ from aqueous solution.In the range of concentration in our study,Qe values of the chemical modified resin NDA-O and non-modified resin NDA-150 were 0.130 mmol/g and 1.749×10-2 mmol/g respectively toward Pb2+,and 0.110 mmol/g and 9.02×10-3 mmol/g respectively toward Cu2+.The adsorption data of both metal ions fit Langmuir equation very well and the adsorption processes were favorable ones.When the metal ions' concentrations at equilibrium were lower than 0.271 mmol/L,the prevailing adsorption mechanism was ion exchange.And when the metal ions' concentrations was higher than 0.378 mmol/L,surface complexation could be considered as well.In our study,the dynamic adsorption capacities of NDA-O toward metal ions were three times as many as those of NDA-150.The resin with metal ions adsorbed could be completely regenerated by washing with 5% hydrochloric acid.
The salicylic acid modified polystyrene was prepared to study adsorption properties toward Pb2+ and Cu2+ from aqueous solution.In the range of concentration in our study,Qe values of the chemical modified resin NDA-O and non-modified resin NDA-150 were 0.130 mmol/g and 1.749×10-2 mmol/g respectively toward Pb2+,and 0.110 mmol/g and 9.02×10-3 mmol/g respectively toward Cu2+.The adsorption data of both metal ions fit Langmuir equation very well and the adsorption processes were favorable ones.When the metal ions' concentrations at equilibrium were lower than 0.271 mmol/L,the prevailing adsorption mechanism was ion exchange.And when the metal ions' concentrations was higher than 0.378 mmol/L,surface complexation could be considered as well.In our study,the dynamic adsorption capacities of NDA-O toward metal ions were three times as many as those of NDA-150.The resin with metal ions adsorbed could be completely regenerated by washing with 5% hydrochloric acid.
2009, 26(2): 224-228
Abstract:
A poly(L-cysteine)/multi-walled carbon nanotube composite(poly-L-cys/MWNT) modified electrode was fabricated by electropolymerization of L-cysteine on a glassy carbon electrode with multi-walled carbon nanotube as dopant.The electrochemical behavior of dopamine(DA) at the modified electrode was studied.The experiment results show that the modified electrode exhibited strong electrocatalytic activity on the oxidation of DA,and the electrode reaction of DA was a quasi-reversible process controlled mainly by adsorption.The oxidation peak current increased linearly with the concentration of DA in a range of 80～0.08 μmol/L.The detection limit was 0.02 μmol/L.Common impurities have no effect on the determination of DA.The modified electrode was applied to assessing the contents of DA in dopamine hydrochloride injection with a recovery of 98%～104%.
A poly(L-cysteine)/multi-walled carbon nanotube composite(poly-L-cys/MWNT) modified electrode was fabricated by electropolymerization of L-cysteine on a glassy carbon electrode with multi-walled carbon nanotube as dopant.The electrochemical behavior of dopamine(DA) at the modified electrode was studied.The experiment results show that the modified electrode exhibited strong electrocatalytic activity on the oxidation of DA,and the electrode reaction of DA was a quasi-reversible process controlled mainly by adsorption.The oxidation peak current increased linearly with the concentration of DA in a range of 80～0.08 μmol/L.The detection limit was 0.02 μmol/L.Common impurities have no effect on the determination of DA.The modified electrode was applied to assessing the contents of DA in dopamine hydrochloride injection with a recovery of 98%～104%.
2009, 26(2): 229-233
Abstract:
A method for the determination of As,Hg,Se,Bi and Sn in antimony concentrates by hydride generation atomic fluorescence spectrometry(HG-AFS) was established.The effects of dissolving sample and concomitant ions were studied.The sample can be completely soluble in aqua regia.Trace arsenic,mercury,selenium,bismuth and tin of real samples were determinated without chemical seperation in the medium with different acidities by adding tartaric acid to inhibit the hydrolysis of antimony.The detection limits were 0.22 μg/L,0.002 μg/L,0.18 μg/L,0.11 μg/L and 0.50 μg/L for As,Hg,Se,Bi and Sn,respectively.The recoveries of the 5 elements were from 88% to 112%.
A method for the determination of As,Hg,Se,Bi and Sn in antimony concentrates by hydride generation atomic fluorescence spectrometry(HG-AFS) was established.The effects of dissolving sample and concomitant ions were studied.The sample can be completely soluble in aqua regia.Trace arsenic,mercury,selenium,bismuth and tin of real samples were determinated without chemical seperation in the medium with different acidities by adding tartaric acid to inhibit the hydrolysis of antimony.The detection limits were 0.22 μg/L,0.002 μg/L,0.18 μg/L,0.11 μg/L and 0.50 μg/L for As,Hg,Se,Bi and Sn,respectively.The recoveries of the 5 elements were from 88% to 112%.
2009, 26(2): 234-236
Abstract:
Condensation of diamine with quinoxaline-2-carboxaldehyde or 2-phenyl-1,2,3-triazole-4-carboxa-ldehyde gave a series of new bis-Schiff bases,which then were reacted with mercaptoacetic acid to afford bis-thiazolidinone derivatives by 1,3-dipolar cycloaddition.The compositions and structures of the new compounds were confirmed by elemental analysis,IR,1H NMR and MS.
Condensation of diamine with quinoxaline-2-carboxaldehyde or 2-phenyl-1,2,3-triazole-4-carboxa-ldehyde gave a series of new bis-Schiff bases,which then were reacted with mercaptoacetic acid to afford bis-thiazolidinone derivatives by 1,3-dipolar cycloaddition.The compositions and structures of the new compounds were confirmed by elemental analysis,IR,1H NMR and MS.
2009, 26(2): 237-239
Abstract:
We developed a simple and efficient three-step method,that is,aldol condensation,aminolysis with gaseous ammonia and reduction by LiAlH4,to synthesize(4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane.The average yield were 52.1%,higher than 22.4% reported in the literature.Five new compounds were synthesized with the new method,and their structures were confirmed by MS-ESI,1H NMR and elemental analysis.
We developed a simple and efficient three-step method,that is,aldol condensation,aminolysis with gaseous ammonia and reduction by LiAlH4,to synthesize(4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane.The average yield were 52.1%,higher than 22.4% reported in the literature.Five new compounds were synthesized with the new method,and their structures were confirmed by MS-ESI,1H NMR and elemental analysis.
2009, 26(2): 240-242
Abstract:
The solubility curves of m-aminophenol in the liquor of m-phenylene diamine and sodium sulfate were examined and established.Solubilities of m-aminophenol in the situation of different concentrations of m-phenylene diamine,quantitative sodium sulfate,various pH and their mixture were determined via HPLC.The experiments proved that the existence of a little amount of m-phenylene diamine had little effect on the solubility of m-aminophenol,and quantitative sodium sulfate made the solubility of m-aminophenol smaller,and m-phenylene diamine and sodium sulfate did not separate out along with MAP crystallization,and the lowest solubility of m-aminophenol was acquired at pH 7.08,with the solubility of MAP of only 0.013~0.032 g/mL below 30 ℃ in the mixture.
The solubility curves of m-aminophenol in the liquor of m-phenylene diamine and sodium sulfate were examined and established.Solubilities of m-aminophenol in the situation of different concentrations of m-phenylene diamine,quantitative sodium sulfate,various pH and their mixture were determined via HPLC.The experiments proved that the existence of a little amount of m-phenylene diamine had little effect on the solubility of m-aminophenol,and quantitative sodium sulfate made the solubility of m-aminophenol smaller,and m-phenylene diamine and sodium sulfate did not separate out along with MAP crystallization,and the lowest solubility of m-aminophenol was acquired at pH 7.08,with the solubility of MAP of only 0.013~0.032 g/mL below 30 ℃ in the mixture.
2009, 26(2): 243-245
Abstract:
We changed the sampling caput of a micro sample injector into micro-conical column where 1,3-propane diamine chelating cotton collulose was packed as adsorption material,and micro conical absorption column was corporated into a combined system of flow injection and flame atomic absorption spectro-photometry(FIAAS).Determination of trace amounts of copper ion in environmental water samples by FIAAS and online preconcentration on micro-column was successfully realized,and the method was applied to Jialing River water samples with satisfactory results.Experiments indicated that the recovery was 99%~107.5% for copper ion and detection limit was 3.5 μg/L,and the RSD was 0.79%.
We changed the sampling caput of a micro sample injector into micro-conical column where 1,3-propane diamine chelating cotton collulose was packed as adsorption material,and micro conical absorption column was corporated into a combined system of flow injection and flame atomic absorption spectro-photometry(FIAAS).Determination of trace amounts of copper ion in environmental water samples by FIAAS and online preconcentration on micro-column was successfully realized,and the method was applied to Jialing River water samples with satisfactory results.Experiments indicated that the recovery was 99%~107.5% for copper ion and detection limit was 3.5 μg/L,and the RSD was 0.79%.
2009, 26(2): 246-248
Abstract:
Cisapride in the tablet was determined indirectly by atomic absorption spectrometry(AAS).After the sample was treated by oxygen flask combustion method,excessive silver nitrate was added to generate insoluble silver chloride precipitate with chloride,and the content of remaining Ag+ in the supernatant was determined by AAS after centrifugal separation,and then the content of cisapride tablet was calculated indirectly.Under the optimum determination conditions,the linear range of this method was 0~3.0 mg/L,and the recovery was 97.5%～103.8%.This method has high accuracy and low detection limit,which is suitable for the determination of cisapride in the cisapride tablet.
Cisapride in the tablet was determined indirectly by atomic absorption spectrometry(AAS).After the sample was treated by oxygen flask combustion method,excessive silver nitrate was added to generate insoluble silver chloride precipitate with chloride,and the content of remaining Ag+ in the supernatant was determined by AAS after centrifugal separation,and then the content of cisapride tablet was calculated indirectly.Under the optimum determination conditions,the linear range of this method was 0~3.0 mg/L,and the recovery was 97.5%～103.8%.This method has high accuracy and low detection limit,which is suitable for the determination of cisapride in the cisapride tablet.
