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2003 Volume 20 Issue 10
2003, 20(10): 919-923
Abstract:
Problems occurred in the conventional methods of synthesis of molecular imprinting polymers(MIPs) are discussed. Recent progress on MIPs synthesis based on surface modification is introduced with emphasis on four methods:method with sacrificial silica-gel plate, method of hydrolytical polycondensation, method based on chemical vapor deposition and method of copolymerization. The application of MIPs in treatment of radioactive waste, capilary electrochromatography, HPLC and catalysis are also noted.
Problems occurred in the conventional methods of synthesis of molecular imprinting polymers(MIPs) are discussed. Recent progress on MIPs synthesis based on surface modification is introduced with emphasis on four methods:method with sacrificial silica-gel plate, method of hydrolytical polycondensation, method based on chemical vapor deposition and method of copolymerization. The application of MIPs in treatment of radioactive waste, capilary electrochromatography, HPLC and catalysis are also noted.
2003, 20(10): 924-927
Abstract:
Palladium catalysts supported on mixed oxides(Pd/nZrO2-mAl2O3) were prepared by copre cipitation and their activities have been examined in catalytic combustion reaction of methane. It was found that the catalyst with n:m=1:5.8 has the highest activity. XRD study revealed that introduction of ZrO2 affects the surface composition and structure of the catalyst, and the catalyst has good activity when ZrO2 is in monclinic phase and has gross porosity. O2-TPD experiments indicated that an appropriate amount of ZrO2 in the com-posite favors the interaction between carrier and noble metal, leading to the formation of a large amount of PdOx active species and increase of catalystic activity in CH4 oxidation reaction.
Palladium catalysts supported on mixed oxides(Pd/nZrO2-mAl2O3) were prepared by copre cipitation and their activities have been examined in catalytic combustion reaction of methane. It was found that the catalyst with n:m=1:5.8 has the highest activity. XRD study revealed that introduction of ZrO2 affects the surface composition and structure of the catalyst, and the catalyst has good activity when ZrO2 is in monclinic phase and has gross porosity. O2-TPD experiments indicated that an appropriate amount of ZrO2 in the com-posite favors the interaction between carrier and noble metal, leading to the formation of a large amount of PdOx active species and increase of catalystic activity in CH4 oxidation reaction.
2003, 20(10): 928-931
Abstract:
Cathode materials LiCo0.2Ni0.8O2, LiCo0.5Ni0.5O2 and LiCo0.8Ni0.2O2 were synthesized by heating mixtures of LiOH with corresponding precursors Co0.2Ni0.8(OH)2, Co0.5Ni0.5(OH)2 and Co0.8Ni0.2(OH)2 obtained from the alloy Co0.2Ni0.8, Co0.5Ni0.5 and Co0.8Ni0.2 by electrolysis, respectively. The experiment results show that all the cathode materials have excellent electrochemical performance, especially those prepared in oxygen atmosphere have high charge-discharge capacity and good recycle property.
Cathode materials LiCo0.2Ni0.8O2, LiCo0.5Ni0.5O2 and LiCo0.8Ni0.2O2 were synthesized by heating mixtures of LiOH with corresponding precursors Co0.2Ni0.8(OH)2, Co0.5Ni0.5(OH)2 and Co0.8Ni0.2(OH)2 obtained from the alloy Co0.2Ni0.8, Co0.5Ni0.5 and Co0.8Ni0.2 by electrolysis, respectively. The experiment results show that all the cathode materials have excellent electrochemical performance, especially those prepared in oxygen atmosphere have high charge-discharge capacity and good recycle property.
2003, 20(10): 932-935
Abstract:
Prepolymer of methyl-triethoxysilicane is used as the crosslinker instead of tetraethyl orthosilane in this paper to prepare the dense polydimethylsiloxane(PDMS) membrane with higher methyl/Si molar ratio for the benzene/water mixture separation. The thickness of unswelling PDMS membrane is 140 μm. XRD shows crystalline content of the membrane is 18.72%. The contact angles of water and benzene on the membrane surface are 113.5° and 20°, respectively. The modified membrane is high hydrophobic. The effects of feed temperature, flow rate, feed concentration and the downstream side pressure on the separation performance of membrane during pervaporation process are evaluated. Experimental results indicate that the increase of the feed concentration, flow rate and feed temperature is in favor of the permeation flux and separation factor, the later increases and the permeation flux decreases with the increase of downstream pressure.
Prepolymer of methyl-triethoxysilicane is used as the crosslinker instead of tetraethyl orthosilane in this paper to prepare the dense polydimethylsiloxane(PDMS) membrane with higher methyl/Si molar ratio for the benzene/water mixture separation. The thickness of unswelling PDMS membrane is 140 μm. XRD shows crystalline content of the membrane is 18.72%. The contact angles of water and benzene on the membrane surface are 113.5° and 20°, respectively. The modified membrane is high hydrophobic. The effects of feed temperature, flow rate, feed concentration and the downstream side pressure on the separation performance of membrane during pervaporation process are evaluated. Experimental results indicate that the increase of the feed concentration, flow rate and feed temperature is in favor of the permeation flux and separation factor, the later increases and the permeation flux decreases with the increase of downstream pressure.
2003, 20(10): 936-941
Abstract:
Ba0.98Ce0.8Eu0.2O3-α solid electrolyte with nonstoichiometric composition has been synthesized by high temperature solid-state reaction. The crystal structure was determined by X-ray diffractometry. Its proton and oxide-ion conduction were investigated in the temperature range of 600~1 000℃ by means of gas concentration cells and electrochemical hydrogen permeation(hydrogen pumping), respectively. Its fuel cell performances were investigated and compared with those of BaCe0.8Eu0.2O3-α solid electrolyte with stoichiometric composition. The experimental results indicate that the sample was a single-phase structure of perovskite-type orthorhombic system. They both have good proton conductivity, and Ba0.98Ce0.8Eu0.2O3-α has higher proton transport numbers in the temperature range of 600~1 000℃ under hydrogen atmosphere. Both of the samples are a mixed conductor of oxide-ion and electron hole with an almost the same oxide-ion transport number under oxygen atmosphere; Ba0.98Ce0.8Eu0.2O3-α has higher mixed ionic transport numbers under fuel cell condition.
Ba0.98Ce0.8Eu0.2O3-α solid electrolyte with nonstoichiometric composition has been synthesized by high temperature solid-state reaction. The crystal structure was determined by X-ray diffractometry. Its proton and oxide-ion conduction were investigated in the temperature range of 600~1 000℃ by means of gas concentration cells and electrochemical hydrogen permeation(hydrogen pumping), respectively. Its fuel cell performances were investigated and compared with those of BaCe0.8Eu0.2O3-α solid electrolyte with stoichiometric composition. The experimental results indicate that the sample was a single-phase structure of perovskite-type orthorhombic system. They both have good proton conductivity, and Ba0.98Ce0.8Eu0.2O3-α has higher proton transport numbers in the temperature range of 600~1 000℃ under hydrogen atmosphere. Both of the samples are a mixed conductor of oxide-ion and electron hole with an almost the same oxide-ion transport number under oxygen atmosphere; Ba0.98Ce0.8Eu0.2O3-α has higher mixed ionic transport numbers under fuel cell condition.
2003, 20(10): 942-945
Abstract:
Monodisperse(dispersion coefficient ε≤0.05) polystyrene microspheres were prepared by dispersion polymerization in ethyl alcohol using polyvinylpyrrolidone(PVP) as a steric stabilizer and 2,2'-azo-bisizobutyronitrile as an initiator. Three batches of 3.0 μm monodisperse polystyrene microspheres were prepared with ethyl alcohol which has been used three times in recycling. The products were characterized by SEM and size analysis. The concentrations of reactants in three batches were examined by gas chromatography. The size of polystyrene microspheres and the dispersion coefficient were ε increased slightly with the times of solvent recycling(D1=3.02 μm, ε1=0.02; D2=3.17 μm,ε2=0.03; D3=3.25 μm, ε3=0.05). But if the dispersion coefficient ε of polystyrene microspheres is beyond 0.05, the ethyl alcohol used must be purified in second batch.
Monodisperse(dispersion coefficient ε≤0.05) polystyrene microspheres were prepared by dispersion polymerization in ethyl alcohol using polyvinylpyrrolidone(PVP) as a steric stabilizer and 2,2'-azo-bisizobutyronitrile as an initiator. Three batches of 3.0 μm monodisperse polystyrene microspheres were prepared with ethyl alcohol which has been used three times in recycling. The products were characterized by SEM and size analysis. The concentrations of reactants in three batches were examined by gas chromatography. The size of polystyrene microspheres and the dispersion coefficient were ε increased slightly with the times of solvent recycling(D1=3.02 μm, ε
2003, 20(10): 946-950
Abstract:
A kind of water-soluble hydroxyl propyl methyl cellulose(HPMC) has been encapsulated on the fine SiO2 particles, and some factors, such as pH value of the medium, encapsulation time and temperature were examined. The results showed that at~60℃ the highest amount of HPMC could be encapsulated on the SiO2 surface, and it increased with increase of time and decrease of pH value. The graft copolymerization of methylmethacrylate(MMA) and butylmethacrylate(BMA) has been carried out on the surface of SiO2/HPMC particles successfully. Encapsulated SiO2 particles being dispersed in PVC have higher impact strength and tensile strength than that of control SiO2 sample in 42.3% and 41%, respectively.
A kind of water-soluble hydroxyl propyl methyl cellulose(HPMC) has been encapsulated on the fine SiO2 particles, and some factors, such as pH value of the medium, encapsulation time and temperature were examined. The results showed that at~60℃ the highest amount of HPMC could be encapsulated on the SiO2 surface, and it increased with increase of time and decrease of pH value. The graft copolymerization of methylmethacrylate(MMA) and butylmethacrylate(BMA) has been carried out on the surface of SiO2/HPMC particles successfully. Encapsulated SiO2 particles being dispersed in PVC have higher impact strength and tensile strength than that of control SiO2 sample in 42.3% and 41%, respectively.
2003, 20(10): 951-954
Abstract:
The carbodiimides 4,obtained by aza Wittig reaction of iminophosphorane 3 with aromatic isocyanates, were reacted with primary alkylamines to give seven title imidazolinones 6a~6g. The structures of the compounds were confirmed by elemental analysis, IR and 1H NMR. The cyclizing reaction of imidazolinones has a certain selectivity. The bioassay tests in vitro revealed 6e showed 71% and 65% inhibitory effect on botrytis cinerea and rhizoctonia solani, respectively.
The carbodiimides 4,obtained by aza Wittig reaction of iminophosphorane 3 with aromatic isocyanates, were reacted with primary alkylamines to give seven title imidazolinones 6a~6g. The structures of the compounds were confirmed by elemental analysis, IR and 1H NMR. The cyclizing reaction of imidazolinones has a certain selectivity. The bioassay tests in vitro revealed 6e showed 71% and 65% inhibitory effect on botrytis cinerea and rhizoctonia solani, respectively.
2003, 20(10): 955-958
Abstract:
A cationic clay stabilizer 2-chloroethyl trimethyl ammonium chloride(CETA) was prepared. The adsorption isotherms of CETA on Ca-montmorillonite were recorded by static method. The Zeta potential of the Ca-montmorillonite suspension as measured by micro-electrophoresis appartus was found increased from nagative to positive value with the increase in concentration of CETA. The lattice spacing of the adsorbed CETA montmorillonite juged by XRD decreased with increase of adsorptive capacity of CETA. At saturation adsorption of CETA the lattice spacing attains the minimal value. The shale recovery experiments showed that it increases with the increase in concentration of CETA. Almost the same shale recovery could be achieved by using 1% KCl solution or 0.1% CETA solution. The result indicate the good inhibition effect of CETA on the clay.
A cationic clay stabilizer 2-chloroethyl trimethyl ammonium chloride(CETA) was prepared. The adsorption isotherms of CETA on Ca-montmorillonite were recorded by static method. The Zeta potential of the Ca-montmorillonite suspension as measured by micro-electrophoresis appartus was found increased from nagative to positive value with the increase in concentration of CETA. The lattice spacing of the adsorbed CETA montmorillonite juged by XRD decreased with increase of adsorptive capacity of CETA. At saturation adsorption of CETA the lattice spacing attains the minimal value. The shale recovery experiments showed that it increases with the increase in concentration of CETA. Almost the same shale recovery could be achieved by using 1% KCl solution or 0.1% CETA solution. The result indicate the good inhibition effect of CETA on the clay.
2003, 20(10): 959-962
Abstract:
The reaction of ferrocenylacrylate with SOCl2 using pyridine as catalyst produced ferrocenylacryl chloride(yield 45%), which in reaction with(substituted) anilines gave thirteen N-aryl-ferrocenylacryl amides(FcCH=CHCONHAr). The method is time saving and easy in seperation and purification of the products. The product compounds have been characterized by elemental analysis, IR and 1H NMR spectra. The results indicate that the kind and position of the substituents in aniline ring greatly affected the conjugation system and coplanarity of the products.
The reaction of ferrocenylacrylate with SOCl2 using pyridine as catalyst produced ferrocenylacryl chloride(yield 45%), which in reaction with(substituted) anilines gave thirteen N-aryl-ferrocenylacryl amides(FcCH=CHCONHAr). The method is time saving and easy in seperation and purification of the products. The product compounds have been characterized by elemental analysis, IR and 1H NMR spectra. The results indicate that the kind and position of the substituents in aniline ring greatly affected the conjugation system and coplanarity of the products.
2003, 20(10): 963-967
Abstract:
The cyanoethylchitosan was prepared to modify the glass carbon electrode through covalent-bond reaction. The cyanoethylchitosan has higher adsorptive capacity and better selectivity for Cu2+. The selectivity of cyanoethylchitosan modified electrode for Cu2+ has been raised significantly, and the common ions didn't interfere with the determination of Cu2+. The sensitivity of modified electrode for Cu2+ is three times that of the unmodified glass carbon in 0.1 mol/L KNO3 solution(pH=3.4). The anodic stripping peak current is linear with Cu2+ concentration in the range of 1.0×10-8~1.0×10-6 g/mL.
The cyanoethylchitosan was prepared to modify the glass carbon electrode through covalent-bond reaction. The cyanoethylchitosan has higher adsorptive capacity and better selectivity for Cu2+. The selectivity of cyanoethylchitosan modified electrode for Cu2+ has been raised significantly, and the common ions didn't interfere with the determination of Cu2+. The sensitivity of modified electrode for Cu2+ is three times that of the unmodified glass carbon in 0.1 mol/L KNO3 solution(pH=3.4). The anodic stripping peak current is linear with Cu2+ concentration in the range of 1.0×10-8~1.0×10-6 g/mL.
2003, 20(10): 968-971
Abstract:
The ZnO powders were prepared separately by decomposition of zinc chelate, W/O micromulsion method and sol-gel method and characterized by XRD and TEM. All the ZnO obtained by mentioned methods has hexagonal wurzite structure. The ZnO prepared by micromulsion method was sized in 20 nm, smaller than that obtained by the two other method, but had better dispersity. The ZnO made by micromulsion method had a sensitivity of 512 to Cl2 at the optimum working temperature 335℃. The response time of ZnO made by micromulsion method was 5 s, and the restoration time was several minutes.
The ZnO powders were prepared separately by decomposition of zinc chelate, W/O micromulsion method and sol-gel method and characterized by XRD and TEM. All the ZnO obtained by mentioned methods has hexagonal wurzite structure. The ZnO prepared by micromulsion method was sized in 20 nm, smaller than that obtained by the two other method, but had better dispersity. The ZnO made by micromulsion method had a sensitivity of 512 to Cl2 at the optimum working temperature 335℃. The response time of ZnO made by micromulsion method was 5 s, and the restoration time was several minutes.
2003, 20(10): 972-976
Abstract:
The kinetics of molecular deposition(MD) of poly (styrenesulfonate)(PSS)/poly(diallyldimethylammonium choloride)(PDDA) films was examined. The kinetics results of molecular adsorption reveal the micromechanism of polyelectrolyte MD film. The linear relationship between UV-Vis absorbance of PSS/PDDA and the number of MD film layers confirms alternative deposition of PSS and PDDA layers as that carried out in deposition process. The great variation of contact angle and UV-Vis absorbance with depositing time indicates that the film formation process of the two polymeric molecules comprises two stages:diffusion controlled rapid langmuir adsorption and relative slow rearrangement of molecules on the surface. For the 6th PSS and 7th PDDA film, the time of adsorption equilibrium is 35 min and 25 min respectively. The adsorption rate constants for PSS and PDDA are found to be 0.604 mL/(g·s) and 1.231 mL/(g·s), respectively.
The kinetics of molecular deposition(MD) of poly (styrenesulfonate)(PSS)/poly(diallyldimethylammonium choloride)(PDDA) films was examined. The kinetics results of molecular adsorption reveal the micromechanism of polyelectrolyte MD film. The linear relationship between UV-Vis absorbance of PSS/PDDA and the number of MD film layers confirms alternative deposition of PSS and PDDA layers as that carried out in deposition process. The great variation of contact angle and UV-Vis absorbance with depositing time indicates that the film formation process of the two polymeric molecules comprises two stages:diffusion controlled rapid langmuir adsorption and relative slow rearrangement of molecules on the surface. For the 6th PSS and 7th PDDA film, the time of adsorption equilibrium is 35 min and 25 min respectively. The adsorption rate constants for PSS and PDDA are found to be 0.604 mL/(g·s) and 1.231 mL/(g·s), respectively.
2003, 20(10): 977-981
Abstract:
The effects of copper oxide and ammonium polyphosphate(APP) alone and in combination on the thermal degradation PA6 have been studied by TGA and FTIR techniques. The results show that CuO alone could lower the on-set temperature and the maximum rate of mass loss of PA6 on heating, increase the apparent activation energy of thermal decomposition of PA6, induce the scission of the N-alkylamide bond and after wards change the thermal degradation process of PA6. In combination of APP, CuO increases the on-set temperature of PA6 from 278℃ to 316℃. The combination of CuO with APP decreases the activation energy of thermal decomposition of PA6. A chemical interaction is shown to take place between ammonium polyphosphate and PA6 on heating, leading to the decrease of apparent activation energy of PA6 and its degradation mechanism.
The effects of copper oxide and ammonium polyphosphate(APP) alone and in combination on the thermal degradation PA6 have been studied by TGA and FTIR techniques. The results show that CuO alone could lower the on-set temperature and the maximum rate of mass loss of PA6 on heating, increase the apparent activation energy of thermal decomposition of PA6, induce the scission of the N-alkylamide bond and after wards change the thermal degradation process of PA6. In combination of APP, CuO increases the on-set temperature of PA6 from 278℃ to 316℃. The combination of CuO with APP decreases the activation energy of thermal decomposition of PA6. A chemical interaction is shown to take place between ammonium polyphosphate and PA6 on heating, leading to the decrease of apparent activation energy of PA6 and its degradation mechanism.
2003, 20(10): 982-985
Abstract:
A phenolic polymeric pseudo crown ether(POCE) was directly synthersized from phenoxy ethanol and formaldehyde in one step. The phenolic resinification was studied by infrared spectrometry. The results show that besides the proportion of phenoxy ethanol to formaldehyde, reaction temperature and time, the crux is the amount of concentrated sulphuric acid used in phenol fromaldehyde condensation when 2-phenoxy ethanol is used as monomer. The polymer has good adsorption properties for Na+, K+, Ca2+, Sr2+, Hg2+, Cu2+, the adsorption capacities are 1.525, 0.849, 2.027, 0.709, 0.815 and 0.406 mmol/g, respectively.
A phenolic polymeric pseudo crown ether(POCE) was directly synthersized from phenoxy ethanol and formaldehyde in one step. The phenolic resinification was studied by infrared spectrometry. The results show that besides the proportion of phenoxy ethanol to formaldehyde, reaction temperature and time, the crux is the amount of concentrated sulphuric acid used in phenol fromaldehyde condensation when 2-phenoxy ethanol is used as monomer. The polymer has good adsorption properties for Na+, K+, Ca2+, Sr2+, Hg2+, Cu2+, the adsorption capacities are 1.525, 0.849, 2.027, 0.709, 0.815 and 0.406 mmol/g, respectively.
2003, 20(10): 986-990
Abstract:
The phase behaviors for three microemulsion systems of MMA/MA/SDS/H2O、MA/SDS/n-butanol/H2O and St/MMA/SDS/H2O(abbr. to MMA, MA and St, respectively) were investigated. For each of the cosurfactant-free systems(MMA,St), there exist only a small single phase microemulsion region near the vertex of surfactant in rich, whereas for the cosurfactant-based system(MA), the area of single phase microemulsion is much larger. The types of the single phase in MA system as characterized by conductivity and viscosity, measurements can be divided into different structural regions:W/O single phase region, bicon-tinuous phase region and O/W single phase region. The relationship of the porous structure of polymer with its pregnant microemulsion was elucidated. By photo-polymerization, microlatex is the only polymer from the system of St, whereas for the other systems, materials from latex to different porous solids can be made according to the structure of precursor microemulsions. For O/W microemulsion, polymer is a semitransparent latex or opaque one, and from W/O microemulsion, product is closed porous materials, whereas for bicontinuous microemulsion, both the polymer and pores have bicontinuous morphology.
The phase behaviors for three microemulsion systems of MMA/MA/SDS/H2O、MA/SDS/n-butanol/H2O and St/MMA/SDS/H2O(abbr. to MMA, MA and St, respectively) were investigated. For each of the cosurfactant-free systems(MMA,St), there exist only a small single phase microemulsion region near the vertex of surfactant in rich, whereas for the cosurfactant-based system(MA), the area of single phase microemulsion is much larger. The types of the single phase in MA system as characterized by conductivity and viscosity, measurements can be divided into different structural regions:W/O single phase region, bicon-tinuous phase region and O/W single phase region. The relationship of the porous structure of polymer with its pregnant microemulsion was elucidated. By photo-polymerization, microlatex is the only polymer from the system of St, whereas for the other systems, materials from latex to different porous solids can be made according to the structure of precursor microemulsions. For O/W microemulsion, polymer is a semitransparent latex or opaque one, and from W/O microemulsion, product is closed porous materials, whereas for bicontinuous microemulsion, both the polymer and pores have bicontinuous morphology.
2003, 20(10): 991-993
Abstract:
A novel mixed oxamate copper(Ⅱ) complex [Cu(phen)(om)(H2O)]·H2O has been obtained and its structure was determined. The complex crystallizes in monoclinic, space group P2(1)/n, a=0.845 3(0) nm, b=0.971 2(1) nm, c=1.742(1) nm, β=103.89(3)°, V=1.388(0) nm3, Z=4, R=0.045 8. The copper atom is five-coordinated with a tetragonal pyramid geometry, the complex molecules are linked to form a one-dimensional network via hydrogen bonding. Its X-band EPR spectrum shows an unsymmetric broad signal with g-tensor value 2.12. The IR, TGA and DTA results are also reported. Thermal degradation of the complex starts at 50℃ to loss water.
A novel mixed oxamate copper(Ⅱ) complex [Cu(phen)(om)(H2O)]·H2O has been obtained and its structure was determined. The complex crystallizes in monoclinic, space group P2(1)/n, a=0.845 3(0) nm, b=0.971 2(1) nm, c=1.742(1) nm, β=103.89(3)°, V=1.388(0) nm3, Z=4, R=0.045 8. The copper atom is five-coordinated with a tetragonal pyramid geometry, the complex molecules are linked to form a one-dimensional network via hydrogen bonding. Its X-band EPR spectrum shows an unsymmetric broad signal with g-tensor value 2.12. The IR, TGA and DTA results are also reported. Thermal degradation of the complex starts at 50℃ to loss water.
2003, 20(10): 994-996
Abstract:
4-Methoxybenzaldehyde is prepared from the addition-hydrolysis reaction of p-CH3OC6H4MgBr with 1,3-disubstituted benzimidazolium salt. The reaction mechanism is discussed. 1,3-Dialkyl has little influence on the yield.
4-Methoxybenzaldehyde is prepared from the addition-hydrolysis reaction of p-CH3OC6H4MgBr with 1,3-disubstituted benzimidazolium salt. The reaction mechanism is discussed. 1,3-Dialkyl has little influence on the yield.
2003, 20(10): 997-999
Abstract:
An electrophoresis technique using a strip of perflurosulfonic acid(Nafion9117) membrane as separation column is described. The narrow hydrophilic pores(diameter 1~2 nm) in Nafion act as electrophoresis channels and the fixed charge sites on the inner surface of the channels provide a strong background electric field. The technique was used to separate the mixture of dopamine and epinephrine under the separation voltage of 100V with a satisfactory efficiency of separation.
An electrophoresis technique using a strip of perflurosulfonic acid(Nafion9117) membrane as separation column is described. The narrow hydrophilic pores(diameter 1~2 nm) in Nafion act as electrophoresis channels and the fixed charge sites on the inner surface of the channels provide a strong background electric field. The technique was used to separate the mixture of dopamine and epinephrine under the separation voltage of 100V with a satisfactory efficiency of separation.
2003, 20(10): 1000-1002
Abstract:
A catalytic spectrophotometric method based on the catalytic effect of Pt(Ⅳ) on the oxidation of 2-(4-chloroe-2-phosphonophenylazo)-7-(4-acetylphenlazo)-1, 8-dihydroxy-3, 6-naphthalenedisulfonicacid(chlorophosphonazo-pA) with KIO4 in acidic medium has been proposed for the determination of trace platinum. The reaction is performed directly in an aqueous solution and the optimal conditions are given. The detection limit is 5.0×10-8 g/mL. The Beer's law is obeyed in the range of 1.5×10-7~3.0×10-7 g/mL. The method has been applied to the determination of platinum in Pt-Pd ores with satisfactory results.
A catalytic spectrophotometric method based on the catalytic effect of Pt(Ⅳ) on the oxidation of 2-(4-chloroe-2-phosphonophenylazo)-7-(4-acetylphenlazo)-1, 8-dihydroxy-3, 6-naphthalenedisulfonicacid(chlorophosphonazo-pA) with KIO4 in acidic medium has been proposed for the determination of trace platinum. The reaction is performed directly in an aqueous solution and the optimal conditions are given. The detection limit is 5.0×10-8 g/mL. The Beer's law is obeyed in the range of 1.5×10-7~3.0×10-7 g/mL. The method has been applied to the determination of platinum in Pt-Pd ores with satisfactory results.
2003, 20(10): 1003-1005
Abstract:
Silane coupling agent was used to introduce polymerizable groups onto the surface of nano-SiO2 particles. Then in-situ polymerization was carried out between the functionalized particles and methacrylic acid monmer to accomplish the surface modification of nano-SiO2. Analysis of FTIR、TEM and TGA results show that methacrylic acid is grafted onto the surface of functionalized particles and the modified particles were stable. Contact angle measurement demonstrated that the modified particles were wetted by toluene completely and the contact angle with water was 105℃, indicating that the hydrophilic surface has been transfered to hydrophobic via the modification.
Silane coupling agent was used to introduce polymerizable groups onto the surface of nano-SiO2 particles. Then in-situ polymerization was carried out between the functionalized particles and methacrylic acid monmer to accomplish the surface modification of nano-SiO2. Analysis of FTIR、TEM and TGA results show that methacrylic acid is grafted onto the surface of functionalized particles and the modified particles were stable. Contact angle measurement demonstrated that the modified particles were wetted by toluene completely and the contact angle with water was 105℃, indicating that the hydrophilic surface has been transfered to hydrophobic via the modification.
2003, 20(10): 1006-1008
Abstract:
The extraction of L-Arginine with di(2-ethylhexyl)phosphoric acid(D2EHPA) has been studied as functions of equilibrium pH, D2EHPA concentration, L-Arginine equilibrium concentration, NH4Cl concentration and temperature. The beffer extraction results were obtained in condition of pH=5~7, D2EHPA 0.2~0.4 mol/L, NH4Cl<0.2 mol/L and low temperature. The equilibrium concentration of L-Arg depends on the saturation extraction capacity.
The extraction of L-Arginine with di(2-ethylhexyl)phosphoric acid(D2EHPA) has been studied as functions of equilibrium pH, D2EHPA concentration, L-Arginine equilibrium concentration, NH4Cl concentration and temperature. The beffer extraction results were obtained in condition of pH=5~7, D2EHPA 0.2~0.4 mol/L, NH4Cl<0.2 mol/L and low temperature. The equilibrium concentration of L-Arg depends on the saturation extraction capacity.
2003, 20(10): 1009-1011
Abstract:
The solid polyferric sulfate(PFS) was made by oxidation of pyrite cinders with NaClO3. It was first time discovered by X-rays diffractometry that when the solid PFS was prepared at temperature below 120℃ the main phase of the solid PFS is Fe4.67(SO4)6(OH)2·20H2O which disappeared when heating was carried out above 130℃ for 2 h and complex physical chemical reactions occurred. In thermal spectra two TG mass loss peaks and DTA exothermic peaks at 170~290℃ and 27~160℃, respectively, were recorded.
The solid polyferric sulfate(PFS) was made by oxidation of pyrite cinders with NaClO3. It was first time discovered by X-rays diffractometry that when the solid PFS was prepared at temperature below 120℃ the main phase of the solid PFS is Fe4.67(SO4)6(OH)2·20H2O which disappeared when heating was carried out above 130℃ for 2 h and complex physical chemical reactions occurred. In thermal spectra two TG mass loss peaks and DTA exothermic peaks at 170~290℃ and 27~160℃, respectively, were recorded.
2003, 20(10): 1012-1014
Abstract:
The method for synthesis of the title compound has been improved, with product yield being increased to 58%. The following measures have been adopted:using 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) as catalyst instead of piperidine; adding benzene in the reaction mixture to favor azeotropic dehydration. The optimum molar ratio of DBU/ethylacetoacetate/solid paraformaldehyde was 4:20:11.
The method for synthesis of the title compound has been improved, with product yield being increased to 58%. The following measures have been adopted:using 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) as catalyst instead of piperidine; adding benzene in the reaction mixture to favor azeotropic dehydration. The optimum molar ratio of DBU/ethylacetoacetate/solid paraformaldehyde was 4:20:11.
2003, 20(10): 1015-1017
Abstract:
The reaction of diketene and cinnamyl alcohol gave cinnamyl acetoacetate. Cinnamyl acetoacetate was ammoniatzed to give cinnamyl 3-aminocrotonate. Methyl acetoacetate condensed with 3-nitrobenzaldehyde to form methyl 2-(3-nitrobenzylidene)acetoacetate which then via. Hantzsch cyclization with cinnamyl 3-aminocrotonate produced new calcicum antagonist pranidipine under mild conditions. The total yield was 69% based on cinnamyl alcohol. Pranidipine synthesized has been characterized by IR、1H NMR、13C NMR and MS spectral measurements.
The reaction of diketene and cinnamyl alcohol gave cinnamyl acetoacetate. Cinnamyl acetoacetate was ammoniatzed to give cinnamyl 3-aminocrotonate. Methyl acetoacetate condensed with 3-nitrobenzaldehyde to form methyl 2-(3-nitrobenzylidene)acetoacetate which then via. Hantzsch cyclization with cinnamyl 3-aminocrotonate produced new calcicum antagonist pranidipine under mild conditions. The total yield was 69% based on cinnamyl alcohol. Pranidipine synthesized has been characterized by IR、1H NMR、13C NMR and MS spectral measurements.
2003, 20(10): 1018-1020
Abstract:
The synthetic method of dimethythiotoluene diamine(DMTDA) has been modified by a in one-pot method from diamin toluene and dimethyldisulfide using zinc iodide as catalyst and dimethyl benzene as inert solvent. Loss of dimethyldisulfide is avoided during the processing, and high purity DMTDA was obtained by acid washing. The structure of DMTDA is characterized by 1H NMR, 13C NMR and IR.
The synthetic method of dimethythiotoluene diamine(DMTDA) has been modified by a in one-pot method from diamin toluene and dimethyldisulfide using zinc iodide as catalyst and dimethyl benzene as inert solvent. Loss of dimethyldisulfide is avoided during the processing, and high purity DMTDA was obtained by acid washing. The structure of DMTDA is characterized by 1H NMR, 13C NMR and IR.
