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2003 Volume 20 Issue 11
2003, 20(11): 1021-1024
Abstract:
Five secondary metabolites 1~5 were isolated from the soft coral Cladiella sp. collected from Sanya bay in Hainan province, China. On the basis of spectroscopic data and chemical degradation, their chemical structures were determined as N-hexadecanoyl-nonadecasphinga-4(E)-ene(1), Pregn-1,20-dien-3-one(2), Pregn-1,4,20-trien-3-one(3), Ergost-5,24(28)-dien-3β-ol(4) and Batyl alcohol(5). Compound 1 is a new marine ceramide.
Five secondary metabolites 1~5 were isolated from the soft coral Cladiella sp. collected from Sanya bay in Hainan province, China. On the basis of spectroscopic data and chemical degradation, their chemical structures were determined as N-hexadecanoyl-nonadecasphinga-4(E)-ene(1), Pregn-1,20-dien-3-one(2), Pregn-1,4,20-trien-3-one(3), Ergost-5,24(28)-dien-3β-ol(4) and Batyl alcohol(5). Compound 1 is a new marine ceramide.
2003, 20(11): 1025-1029
Abstract:
The influences of additives LaCl3 and Fe2(SO4)3 in plating solution for electroless Ni-W-P deposition have been investigated as function of deposition rate, composition, structure and morphology of alloy formed. The results show that 1~10 mg/L LaCl3 could accelerate deposition rate, whereas 20~100 mg/L LaCl3 decrease deposition rate, reduce W content and diminish the grain size. Being different from LaCl3, Fe2(SO4)3 could increase deposition rate, reduce P content, and hardly affect the grain size. Energy Diffusion Specta (EDS) indicate LaCl3 is not a consumptive additive, but Fe2(SO4)3 is. Fe2(SO4)3 raises deposition rate by forming catalytic centres, being deposited on the substrate surface.
The influences of additives LaCl3 and Fe2(SO4)3 in plating solution for electroless Ni-W-P deposition have been investigated as function of deposition rate, composition, structure and morphology of alloy formed. The results show that 1~10 mg/L LaCl3 could accelerate deposition rate, whereas 20~100 mg/L LaCl3 decrease deposition rate, reduce W content and diminish the grain size. Being different from LaCl3, Fe2(SO4)3 could increase deposition rate, reduce P content, and hardly affect the grain size. Energy Diffusion Specta (EDS) indicate LaCl3 is not a consumptive additive, but Fe2(SO4)3 is. Fe2(SO4)3 raises deposition rate by forming catalytic centres, being deposited on the substrate surface.
2003, 20(11): 1030-1034
Abstract:
Cotton pulp cellulose was treated by ultrasonic wave. The DP, morphology, structure and crystal performance of the original and treated cellulose sample were characterized by viscosimetry, SEM, FTIR and WAXD. The result shows that the ultrasonic wave decreases the crystallinity of cellulose destroying the intermolecular hydrogen bonding effectively and improves the dissolution of cellulose, but does not cause degradation. The surface apperance of cellulose also changed after ultrasonic treatment. The mechanism of activation of ultrasonic wave was discussed primarily.
Cotton pulp cellulose was treated by ultrasonic wave. The DP, morphology, structure and crystal performance of the original and treated cellulose sample were characterized by viscosimetry, SEM, FTIR and WAXD. The result shows that the ultrasonic wave decreases the crystallinity of cellulose destroying the intermolecular hydrogen bonding effectively and improves the dissolution of cellulose, but does not cause degradation. The surface apperance of cellulose also changed after ultrasonic treatment. The mechanism of activation of ultrasonic wave was discussed primarily.
2003, 20(11): 1035-1038
Abstract:
Melamine polyphosphate(MPOP) was synthesized from melamine and polyphosphoric acid in methanol using silicotungstic acid as catalyst and characterized by elemental analysis, IR, XRD, TG and DSC. Its fire retardant performance is evaluated. The results show that melamine polyphosphate prepared has higher purity and yield. The thermal analysis shows melamine polyphosphate undergoes a continuously rapid mass loss until 684.8℃. The residue is 43.52% of the original mass. A distinct heat absorption is found at 653.5℃ on DSC curve of melamine polyphosphate with heat absorption capacity of 629.1 J/g. A melamine polyphosphate coating in 1 mm thickness on five-ply board gives a 16 minutes fire-resistance limit as obtained in a big panel combustion test. The foaming capacity is 50~60.
Melamine polyphosphate(MPOP) was synthesized from melamine and polyphosphoric acid in methanol using silicotungstic acid as catalyst and characterized by elemental analysis, IR, XRD, TG and DSC. Its fire retardant performance is evaluated. The results show that melamine polyphosphate prepared has higher purity and yield. The thermal analysis shows melamine polyphosphate undergoes a continuously rapid mass loss until 684.8℃. The residue is 43.52% of the original mass. A distinct heat absorption is found at 653.5℃ on DSC curve of melamine polyphosphate with heat absorption capacity of 629.1 J/g. A melamine polyphosphate coating in 1 mm thickness on five-ply board gives a 16 minutes fire-resistance limit as obtained in a big panel combustion test. The foaming capacity is 50~60.
2003, 20(11): 1039-1043
Abstract:
The Ni2(OCH3)2/SiO2 catalyst was prepared by surface modification reaction and ion-exchange method. The surface structure, chemisorption and reactivity of the catalyst were examined by IR and supercritical reaction. The experiment results indicated that Ni2+is bond with surface O2- of SiO2 support in bidentate fashion in the supported dinuclear bridged methoxide complex Ni2(OCH3)2, that the CO2 is chemically adsorbed on the catalysts in bridged adsorption state and carbonate species and the propylene is chemically adsorbed on the catalyst in a molecular adsorption state. Under supercritical condition 313 K, 7.5 MPa and reaction time 3 h, the Ni2(OCH3)2/SiO2 catalyst gave almost 100% methacrylic acid from CO2 and propylene in synthesis.
The Ni2(OCH3)2/SiO2 catalyst was prepared by surface modification reaction and ion-exchange method. The surface structure, chemisorption and reactivity of the catalyst were examined by IR and supercritical reaction. The experiment results indicated that Ni2+is bond with surface O2- of SiO2 support in bidentate fashion in the supported dinuclear bridged methoxide complex Ni2(OCH3)2, that the CO2 is chemically adsorbed on the catalysts in bridged adsorption state and carbonate species and the propylene is chemically adsorbed on the catalyst in a molecular adsorption state. Under supercritical condition 313 K, 7.5 MPa and reaction time 3 h, the Ni2(OCH3)2/SiO2 catalyst gave almost 100% methacrylic acid from CO2 and propylene in synthesis.
2003, 20(11): 1044-1047
Abstract:
A fullerene-styrene-methacrylic acid copolymer was synthesized via radical polymerization and characlerized by FTIR, UV-Vis and GPC. The copolymer is soluble in polar solvents such as water, methanol, acetone, tetrahydrofuran. TEM observation revealed its ideal spherical shape in water with an average diameter of about 40 nm. Four-ball machine tests indicated that addition of an amount of 0.5%(mass fraction) the fullerene copolymer to base stock can effectively increase the bearing capacity(PB value) and the antiwearing ability of the base stock(2%(mass fraction) of triethanolamine and 0.5%(mass fraction) of OPZ aqueous solution). The morphology study of the worn surfaces by SEM showed that addition of the copolymer leads to reduction of wear scar size and decrease of wear depth. With the increasing of the content of the fullerene copolymer, the friction coefficient reduces rapidly from 0.233 for base stock to minimum value of 0.061 5. With the increasing of the added fullerene cop/lymer, bearing capacity increases rapidly from 135 N for base stock to maximum value of 490 N.
A fullerene-styrene-methacrylic acid copolymer was synthesized via radical polymerization and characlerized by FTIR, UV-Vis and GPC. The copolymer is soluble in polar solvents such as water, methanol, acetone, tetrahydrofuran. TEM observation revealed its ideal spherical shape in water with an average diameter of about 40 nm. Four-ball machine tests indicated that addition of an amount of 0.5%(mass fraction) the fullerene copolymer to base stock can effectively increase the bearing capacity(PB value) and the antiwearing ability of the base stock(2%(mass fraction) of triethanolamine and 0.5%(mass fraction) of OPZ aqueous solution). The morphology study of the worn surfaces by SEM showed that addition of the copolymer leads to reduction of wear scar size and decrease of wear depth. With the increasing of the content of the fullerene copolymer, the friction coefficient reduces rapidly from 0.233 for base stock to minimum value of 0.061 5. With the increasing of the added fullerene cop/lymer, bearing capacity increases rapidly from 135 N for base stock to maximum value of 490 N.
2003, 20(11): 1048-1051
Abstract:
A hydrophobically associating water-soluble polymer HAWP-18 has been synthesized by copoly-merization of acrylamide(AM), sodium acrylate(NaAA) and octadecyl dimethylallyl ammonium chloride(MJ-18). The effects of copolymer concentration, salt concentration, temperature and surfactant concentration on the viscosity of the copolymer have been studied. The results show that the solution viscosity increases sharply when the mass fraction of the copolymer is higher than critical associating concentration(c*); the viscosity of the dilute solution of the polymer decreases swiftly when NaCl is added, but that of the semidilute one increases; on adding of CaCl2, the apparent viscosity increases at first and then decreases. The viscosity of copolymer solution has a maximum value as function of sodium dodecyl sulfate(SDS) added.
A hydrophobically associating water-soluble polymer HAWP-18 has been synthesized by copoly-merization of acrylamide(AM), sodium acrylate(NaAA) and octadecyl dimethylallyl ammonium chloride(MJ-18). The effects of copolymer concentration, salt concentration, temperature and surfactant concentration on the viscosity of the copolymer have been studied. The results show that the solution viscosity increases sharply when the mass fraction of the copolymer is higher than critical associating concentration(c*); the viscosity of the dilute solution of the polymer decreases swiftly when NaCl is added, but that of the semidilute one increases; on adding of CaCl2, the apparent viscosity increases at first and then decreases. The viscosity of copolymer solution has a maximum value as function of sodium dodecyl sulfate(SDS) added.
2003, 20(11): 1052-1056
Abstract:
Ni/La-Ce-Al2O3, Pd/La-Ce-Al2O3, Pd/Ni/La-Ce-Al2O3 catalysts were prepared with cordierite (2MgO·2Al2O3·5SiO2)as support by impregnation method. The influence of Ni on the catalytic activity of the catalysts(ω(Pd)=0.08%)for control of automotive exhausts was studied by TPR, CO-TPD, O2-TPD, C3H6-TPD. The activity of the catalysts in reduction of NO and oxidation of C3H8 and CO was found to be increased in the order Pd/Ni/La-Ce-Al2O3 >Pd/La-Ce-Al2O3 >Ni/La-Ce-Al2O3. It is suggested that single Ni is low in activity, but being a promotor, it increase the activity of Pd/La-Ce-Al2O3. The decrease of the conversion temperature(T100%)of NO, CO and C3H8 in mentioned reactions over this catalyst was <10℃, 10℃ and 50℃ respectively. Meanwhile, Ni also decreases the reduction temperature of oxygen species in catalyst and the desorption temperature of CO, but increases the desorption temperature of O2.
Ni/La-Ce-Al2O3, Pd/La-Ce-Al2O3, Pd/Ni/La-Ce-Al2O3 catalysts were prepared with cordierite (2MgO·2Al2O3·5SiO2)as support by impregnation method. The influence of Ni on the catalytic activity of the catalysts(ω(Pd)=0.08%)for control of automotive exhausts was studied by TPR, CO-TPD, O2-TPD, C3H6-TPD. The activity of the catalysts in reduction of NO and oxidation of C3H8 and CO was found to be increased in the order Pd/Ni/La-Ce-Al2O3 >Pd/La-Ce-Al2O3 >Ni/La-Ce-Al2O3. It is suggested that single Ni is low in activity, but being a promotor, it increase the activity of Pd/La-Ce-Al2O3. The decrease of the conversion temperature(T100%)of NO, CO and C3H8 in mentioned reactions over this catalyst was <10℃, 10℃ and 50℃ respectively. Meanwhile, Ni also decreases the reduction temperature of oxygen species in catalyst and the desorption temperature of CO, but increases the desorption temperature of O2.
2003, 20(11): 1057-1061
Abstract:
Obvious electrochemical oscillations in Daniell cell, including electromotive force oscillation and its electrode reaction oscillation, were found as adding emulsion to form electrolytic emulsion. The conductivity and microscope results on the emulsion show that there is a close relationship between the electrochemical oscillations and the change of emulsion construction. A series of oscillating reactions were discussed in terms of correlation analysis for different emulsions and different cells. When the oscillation finished, an alternating electric current in 2 V with certain frequency was given on the system for 4 h, the oscillation was found to be regenerated. Thus a reversible chemical oscillator was formed. This is very important for complexity kinetics study and producing colloid secondary battery.
Obvious electrochemical oscillations in Daniell cell, including electromotive force oscillation and its electrode reaction oscillation, were found as adding emulsion to form electrolytic emulsion. The conductivity and microscope results on the emulsion show that there is a close relationship between the electrochemical oscillations and the change of emulsion construction. A series of oscillating reactions were discussed in terms of correlation analysis for different emulsions and different cells. When the oscillation finished, an alternating electric current in 2 V with certain frequency was given on the system for 4 h, the oscillation was found to be regenerated. Thus a reversible chemical oscillator was formed. This is very important for complexity kinetics study and producing colloid secondary battery.
2003, 20(11): 1062-1065
Abstract:
The thermodynamic properties of hypercrosslinked resins AM-1 and macroporous adsorbent Amberlite XAD-4 in adsorption of aniline and 4-nitroaniline in aqueous solution have been studied under the static conditions. The results show that the adsorptions of aniline and 4-nitroaniline in dilute aqueous solution on the two adsorbents are both fit for Langmuir and Freundlich equations and the adsorptions of aniline and 4-nitroaniline on AM-1 are an endothermic process and considerable increase of temperature is in favor of the absorption. The thermodynamic calculations and the adsorption isotherms obtained at different temperature reveal the existence of chemical adsorption in the adsorption processes of AM-1 resin for two chemicals studied.
The thermodynamic properties of hypercrosslinked resins AM-1 and macroporous adsorbent Amberlite XAD-4 in adsorption of aniline and 4-nitroaniline in aqueous solution have been studied under the static conditions. The results show that the adsorptions of aniline and 4-nitroaniline in dilute aqueous solution on the two adsorbents are both fit for Langmuir and Freundlich equations and the adsorptions of aniline and 4-nitroaniline on AM-1 are an endothermic process and considerable increase of temperature is in favor of the absorption. The thermodynamic calculations and the adsorption isotherms obtained at different temperature reveal the existence of chemical adsorption in the adsorption processes of AM-1 resin for two chemicals studied.
2003, 20(11): 1066-1070
Abstract:
The stearic acid treated CaCO3 nanoparticles(abbraviated particle A) and their PMMA covered ones(abbraviated particle B) were blended with polypropylene(PP) to give PP/CaCO3 and PP/PMMA/CaCO3 nanocomposites. The size and dispersion of surface treated CaCO3 nano-particles were studied by TEM. The results showed that PMMA/CaCO3 composited nanoparticles were relatively homogeneously dispersed in PP matrix. The crystallization behavior of the nanocomposites were investigated by means of DSC and WAXD measurements. The β-type crystal of PP was observed, could be due to the heterogeneous nucleation of PP with PMMA/CaCO3 particles on blending. The mechanical propertyes of the PP/PMMA/CaCO3 nanocomposites prepared were greatly improved.
The stearic acid treated CaCO3 nanoparticles(abbraviated particle A) and their PMMA covered ones(abbraviated particle B) were blended with polypropylene(PP) to give PP/CaCO3 and PP/PMMA/CaCO3 nanocomposites. The size and dispersion of surface treated CaCO3 nano-particles were studied by TEM. The results showed that PMMA/CaCO3 composited nanoparticles were relatively homogeneously dispersed in PP matrix. The crystallization behavior of the nanocomposites were investigated by means of DSC and WAXD measurements. The β-type crystal of PP was observed, could be due to the heterogeneous nucleation of PP with PMMA/CaCO3 particles on blending. The mechanical propertyes of the PP/PMMA/CaCO3 nanocomposites prepared were greatly improved.
2003, 20(11): 1071-1075
Abstract:
The thermodynamic property of HCl-CoSO4 system has been studied by the emf measurement in the following cell(A) without liquid junction: Pt,H2(105Pa)|HCl(cA),CoSO4(cB),H2O|AgCl-Ag (A) at constant total ionic strength I=0.2、0.4、0.6、0.8、1.0、1.5 mol/kg and yB=0.00、0.10、0.20、0.30、0.50、0.70 at temperatures from 278.15 to 323.15 K.The activity coefficients of HCl, lg γA, for HCl-CoSO4 system have been determined from cell(A). The results show that the activity coefficients of HCl in the solutions still obey Harned's rule and lg γA is in linear function with the reciprocal of the absolute temperature at constant composition of the mixture.
The thermodynamic property of HCl-CoSO4 system has been studied by the emf measurement in the following cell(A) without liquid junction: Pt,H2(105Pa)|HCl(cA),CoSO4(cB),H2O|AgCl-Ag (A) at constant total ionic strength I=0.2、0.4、0.6、0.8、1.0、1.5 mol/kg and yB=0.00、0.10、0.20、0.30、0.50、0.70 at temperatures from 278.15 to 323.15 K.The activity coefficients of HCl, lg γA, for HCl-CoSO4 system have been determined from cell(A). The results show that the activity coefficients of HCl in the solutions still obey Harned's rule and lg γA is in linear function with the reciprocal of the absolute temperature at constant composition of the mixture.
2003, 20(11): 1076-1079
Abstract:
Sb/SnO2 ultrafine powder water-dispersion prepared by a ball-grinding method has been investigated as function of pH value, Sb concentration and calcination temperature by measurements of the Zeta potential and sedimentation rate of the dispersion. The results indicate that the Sb/SnO2 ultrafine powder dispersion is dependent on the preparation conditions through their effects on the surface state, chemical composition and crystal state of the final products. The zero Zeta potential point of the Sb/SnO2 ultrafine powder is about 1.8. The proper conditions for higher stable Sb/SnO2 ultrafine powder water-dispersion are: pH=10.0~11.5, n(Sb)/n(Sn) 0.04~0.19 and calcination temperature 800℃.
Sb/SnO2 ultrafine powder water-dispersion prepared by a ball-grinding method has been investigated as function of pH value, Sb concentration and calcination temperature by measurements of the Zeta potential and sedimentation rate of the dispersion. The results indicate that the Sb/SnO2 ultrafine powder dispersion is dependent on the preparation conditions through their effects on the surface state, chemical composition and crystal state of the final products. The zero Zeta potential point of the Sb/SnO2 ultrafine powder is about 1.8. The proper conditions for higher stable Sb/SnO2 ultrafine powder water-dispersion are: pH=10.0~11.5, n(Sb)/n(Sn) 0.04~0.19 and calcination temperature 800℃.
2003, 20(11): 1080-1083
Abstract:
The cellulose nitrate containing secondary amine group(ACN) was prepared by one-pot method in two steps: etherification and amination. Its structure was confirmed by elemental analysis, IR, 13C NMR, and XPS. ACN has a good adsorption property for creatinine. The equilibrium adsorption ratio of ACN for creatinine was 68% at 37℃, 0.5 g ACN, respectively, at pH=7 and creatinine concentration of 60 mg/L. The equilibrium time was 2 h.
The cellulose nitrate containing secondary amine group(ACN) was prepared by one-pot method in two steps: etherification and amination. Its structure was confirmed by elemental analysis, IR, 13C NMR, and XPS. ACN has a good adsorption property for creatinine. The equilibrium adsorption ratio of ACN for creatinine was 68% at 37℃, 0.5 g ACN, respectively, at pH=7 and creatinine concentration of 60 mg/L. The equilibrium time was 2 h.
2003, 20(11): 1084-1087
Abstract:
The resolution of propranolol enantiomers has been sucessfully carried out by HPLC using two phase discrimination:γ-amino propyl silica gel coated with 15%(mass fraction) of cellulose tribenzoate(CTB) as chiral stationary phase and hexane-alcohol(V:V=85:15) soltuion containing 0.40 mmol/L N-benzyloxycarbonyl-S-phenyl-L-cysteine(BPC) as chiral mobile phase. The chromatiographic method with flow rate of 0.3 mL/min and UV detection at 254 nm gave a separation selectivity of 1.30 and a separation degree of 1.56. The discrimination of CTB to propranolol enantiomers was apparently improved by the presence of BPC. The resolution mechanism of the two-phases discrimination has been discussed based on the thermodynamic parameters obtained.
The resolution of propranolol enantiomers has been sucessfully carried out by HPLC using two phase discrimination:γ-amino propyl silica gel coated with 15%(mass fraction) of cellulose tribenzoate(CTB) as chiral stationary phase and hexane-alcohol(V:V=85:15) soltuion containing 0.40 mmol/L N-benzyloxycarbonyl-S-phenyl-L-cysteine(BPC) as chiral mobile phase. The chromatiographic method with flow rate of 0.3 mL/min and UV detection at 254 nm gave a separation selectivity of 1.30 and a separation degree of 1.56. The discrimination of CTB to propranolol enantiomers was apparently improved by the presence of BPC. The resolution mechanism of the two-phases discrimination has been discussed based on the thermodynamic parameters obtained.
2003, 20(11): 1088-1092
Abstract:
Eight 3-alkoxy-6-(4-cholesteryloxycarbonylphenyl) pyridazines containing a pyridazine ring, a benzene ring, a cholesteryl, an ester group and an alkoxyl group of different length were synthesized through the cross-coupling reaction of 3-chloro-6-alkoxypyridazines and p-cholesteryloxycarbonylphenylboronic acid in the presence of palladium catalyst. The reaction of 3,6-dichloropyridazine with the alcohol under phase transfer catalyst gives 3-chloro-6-alkoxypyridazine. Their mesomorphism was studied by differential scanning calorimetry. The results showed that seven compounds have mesomorphism. The length of the terminal chain could affect the phase transition and clearing point temperatures of the compounds, but it has little influence on the temperature range of mesomorphous phases.
Eight 3-alkoxy-6-(4-cholesteryloxycarbonylphenyl) pyridazines containing a pyridazine ring, a benzene ring, a cholesteryl, an ester group and an alkoxyl group of different length were synthesized through the cross-coupling reaction of 3-chloro-6-alkoxypyridazines and p-cholesteryloxycarbonylphenylboronic acid in the presence of palladium catalyst. The reaction of 3,6-dichloropyridazine with the alcohol under phase transfer catalyst gives 3-chloro-6-alkoxypyridazine. Their mesomorphism was studied by differential scanning calorimetry. The results showed that seven compounds have mesomorphism. The length of the terminal chain could affect the phase transition and clearing point temperatures of the compounds, but it has little influence on the temperature range of mesomorphous phases.
2003, 20(11): 1093-1095
Abstract:
Oxygen-permeable membranes derived from SrFe0.2Co0.8O3-δ were investigated aiming at improving the permeability and integrity. An oxygen flux as large as 1.52×10-6 mol/(cm2·s) was observed for a 0.1 cm thick membrane of Ba0.1Sr0.9Sn0.1Fe0.1Co0.8O3-δ at 900℃ under a relatively small oxygen partial pressure gradient across the membrane(P'O2=2.13×104 Pa, P"O2=9.12×102 Pa). The improved oxygen permeability may be attributed to the weaker association of oxygen vacancies as a consequence of partial substitution of Ba for Sr. The improved membrane stability of Sn-doped sample is likely due to the formation of SrSnO3 second phase since the non-crystal Sr in grain boundaries is prior to reacting with Sn, which made the membrane more resistant to the corrosion from CO2 and water vapor.
Oxygen-permeable membranes derived from SrFe0.2Co0.8O3-δ were investigated aiming at improving the permeability and integrity. An oxygen flux as large as 1.52×10-6 mol/(cm2·s) was observed for a 0.1 cm thick membrane of Ba0.1Sr0.9Sn0.1Fe0.1Co0.8O3-δ at 900℃ under a relatively small oxygen partial pressure gradient across the membrane(P'O2=2.13×104 Pa, P"O2=9.12×102 Pa). The improved oxygen permeability may be attributed to the weaker association of oxygen vacancies as a consequence of partial substitution of Ba for Sr. The improved membrane stability of Sn-doped sample is likely due to the formation of SrSnO3 second phase since the non-crystal Sr in grain boundaries is prior to reacting with Sn, which made the membrane more resistant to the corrosion from CO2 and water vapor.
2003, 20(11): 1096-1098
Abstract:
TiO2 nanoparticles were obtained from industrial TiOSO4 by hydrolysis method. SnO2/TiO2 and SnO2-TiO2 composite powders were prepared by stepwise precipitation method and coating method, respectively. The phase transformation of TiO2 and the effect of composite mode of SnO2 on phase transformation of TiO2 have been investigated by TG-DTA and XRD. The phase transform of pure TiO2 from anatase to rutile begins at 750℃ and the presence of SnO2 markedly reduces the transform temperature: for coated SnO2-TiO2 composite with ω(SnO2)=20% it was 400℃. The SnO2/TiO2 composite prepared by precipitation method and followed by calcination at 400℃ for 30 min possesses 55% rutile TiO2. The formation of SnO2-TiO2 solid-solution occurrs mainly due to the substitution of Ti4+ crystal lattice sites by Sn4+ ions of SnO2.
TiO2 nanoparticles were obtained from industrial TiOSO4 by hydrolysis method. SnO2/TiO2 and SnO2-TiO2 composite powders were prepared by stepwise precipitation method and coating method, respectively. The phase transformation of TiO2 and the effect of composite mode of SnO2 on phase transformation of TiO2 have been investigated by TG-DTA and XRD. The phase transform of pure TiO2 from anatase to rutile begins at 750℃ and the presence of SnO2 markedly reduces the transform temperature: for coated SnO2-TiO2 composite with ω(SnO2)=20% it was 400℃. The SnO2/TiO2 composite prepared by precipitation method and followed by calcination at 400℃ for 30 min possesses 55% rutile TiO2. The formation of SnO2-TiO2 solid-solution occurrs mainly due to the substitution of Ti4+ crystal lattice sites by Sn4+ ions of SnO2.
2003, 20(11): 1099-1101
Abstract:
Camphorsulfonic acid doped polyaniline(PANI·HCSA) with was prepared by a solid-state method and characterized by FT-IR, XRD, cyclovoltammetry, UV-Vis spectroscopy, SEM and viscometry. The results showed that the polyaniline obtained displayed higher crystallinity, less structural defects and spherical microstructure, high inherent viscosity(1.61 dL/g) and better electrochemical stability.
Camphorsulfonic acid doped polyaniline(PANI·HCSA) with was prepared by a solid-state method and characterized by FT-IR, XRD, cyclovoltammetry, UV-Vis spectroscopy, SEM and viscometry. The results showed that the polyaniline obtained displayed higher crystallinity, less structural defects and spherical microstructure, high inherent viscosity(1.61 dL/g) and better electrochemical stability.
2003, 20(11): 1102-1104
Abstract:
A new large conjugated ligand 1',8'-diaza-anthreceno-[a,5,6]-1,10-phenanthroline(dap) and its Fe(Ⅱ) complex have been synthesized from phenanthroline and 2,3-diaminonphthalene. The structures and properties of the ligand and the complex were characterized by elemental analysis, IR, MS, UV-vis spectrometry. The study of magnetic susceptibility of the complex indicated the complex lies mainly in low spin state between 80~300 K, while a spin crossover occurs in high temperature region as a result of the stronger ligand field of this ligand than those of dipyrido[3,2-a:2'3'-c] phenazine and dipyrazine[2,3f:2',3'h] quinoxaline.
A new large conjugated ligand 1',8'-diaza-anthreceno-[a,5,6]-1,10-phenanthroline(dap) and its Fe(Ⅱ) complex have been synthesized from phenanthroline and 2,3-diaminonphthalene. The structures and properties of the ligand and the complex were characterized by elemental analysis, IR, MS, UV-vis spectrometry. The study of magnetic susceptibility of the complex indicated the complex lies mainly in low spin state between 80~300 K, while a spin crossover occurs in high temperature region as a result of the stronger ligand field of this ligand than those of dipyrido[3,2-a:2'3'-c] phenazine and dipyrazine[2,3f:2',3'h] quinoxaline.
2003, 20(11): 1105-1107
Abstract:
Studies on the adsorption of Pd2+ ion by Nitzschia hantzschiana Rabh., a diatom were carried out. Uniform design was used to arrange the experiment. The growth period of diatom, adsorption time, concentration of Pd2+ and pH were found to have positive effects on the adsorption amount of Pd2+ on diatom. The optimum conditions are: the growth period of diatom 12 days, adsorption time=6 h, [Pd2+]=0.01 g/L and [H+]=0.16 mol/L. EPMA analysis showed that the diameter of the reduced adsorbed Pd was about 1 μm. A mathematical model was found to describe experimental data, that the adsorption fits to Freundlich equation, Q=70.2[Pd2+]0.76. The adsorption amount of Pd2+ on diatom increased logarithmically with the increase of Pd2+ concentration.
Studies on the adsorption of Pd2+ ion by Nitzschia hantzschiana Rabh., a diatom were carried out. Uniform design was used to arrange the experiment. The growth period of diatom, adsorption time, concentration of Pd2+ and pH were found to have positive effects on the adsorption amount of Pd2+ on diatom. The optimum conditions are: the growth period of diatom 12 days, adsorption time=6 h, [Pd2+]=0.01 g/L and [H+]=0.16 mol/L. EPMA analysis showed that the diameter of the reduced adsorbed Pd was about 1 μm. A mathematical model was found to describe experimental data, that the adsorption fits to Freundlich equation, Q=70.2[Pd2+]0.76. The adsorption amount of Pd2+ on diatom increased logarithmically with the increase of Pd2+ concentration.
2003, 20(11): 1108-1110
Abstract:
Distribution behavior of mandelic acid enantiomers was examined in a two-phase aqueous-organic solvent mixture containing L-tartaric esters. The influences of pH, length of alkyl chain of L-tartraic esters, organic solvents and concentrations of phosphate salt on partition coefficient(K) and separation factor(α) were investigated. The results show that L-tartaric esters studied all form more stable diastereomeric complexes with D-enantiomer than with L-enantiomer. With rise of pH, K decrease, but α increase. With addition of length of alkyl chain of L-tartaric esters, K and α decrease. Organic solvents and concentrations of phosphate salt also show a great influence on K and α. KL, KD and α are 2.523, 2.674 and 1.06, respectively, when mandelic acid enantiomers were extracted by di-O-pentyl-L-tartaric ester in n-decanol at pH=2.3.
Distribution behavior of mandelic acid enantiomers was examined in a two-phase aqueous-organic solvent mixture containing L-tartaric esters. The influences of pH, length of alkyl chain of L-tartraic esters, organic solvents and concentrations of phosphate salt on partition coefficient(K) and separation factor(α) were investigated. The results show that L-tartaric esters studied all form more stable diastereomeric complexes with D-enantiomer than with L-enantiomer. With rise of pH, K decrease, but α increase. With addition of length of alkyl chain of L-tartaric esters, K and α decrease. Organic solvents and concentrations of phosphate salt also show a great influence on K and α. KL, KD and α are 2.523, 2.674 and 1.06, respectively, when mandelic acid enantiomers were extracted by di-O-pentyl-L-tartaric ester in n-decanol at pH=2.3.
2003, 20(11): 1111-1113
Abstract:
Five novel cis-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropyl formyl thiourea derivatives(4a~4e) have been synthesized. Their structures are characterized by 1H NMR, IR and elemental analysis. The preliminary herbicidal tests indicate the compound 4a shows a better inhibitory activity to broad leaf plant, 4d and 4e to monoctyledon plant, respectively.
Five novel cis-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropyl formyl thiourea derivatives(4a~4e) have been synthesized. Their structures are characterized by 1H NMR, IR and elemental analysis. The preliminary herbicidal tests indicate the compound 4a shows a better inhibitory activity to broad leaf plant, 4d and 4e to monoctyledon plant, respectively.
2003, 20(11): 1114-1116
Abstract:
Using acetone-water as medium and 2,2'-azobisisobutyramidine dihydrochloride(AIBA) as cationic radical initiator, three emulsifier-free cationic copolymer nanoparticles were synthesized under microwave irradiation from styrene with methylmethacrylate, diacetoneacrylamide and β-hydroxyethyl-methacrylate respectively. The latexes were excellently stable. The particles were characterized by IR, TEM, LLS. The influence of comonomer content and hydrophilicity on the hydrodynamic radius of copolymer nanoparticles was discussed. The results indicated that the average of copolymer particle decreased with increase of the concentration and hydrophilicity of the comonomer.
Using acetone-water as medium and 2,2'-azobisisobutyramidine dihydrochloride(AIBA) as cationic radical initiator, three emulsifier-free cationic copolymer nanoparticles were synthesized under microwave irradiation from styrene with methylmethacrylate, diacetoneacrylamide and β-hydroxyethyl-methacrylate respectively. The latexes were excellently stable. The particles were characterized by IR, TEM, LLS. The influence of comonomer content and hydrophilicity on the hydrodynamic radius
2003, 20(11): 1117-1119
Abstract:
The air-tightness and conductivity of NR/CSF and NBR/CSF vulcanizates were studied. The results showed that the carbon black bound rubber content of NR or NBR compounds with 50 phr of CSF were higher than those with the same amount of acetylene black(ACET) or high abrasion furnace black(HAF). In addition, the yield strength(Ty) and tensile strength(Tb) of their compounds were also higher than those of the latter, and the more the loading of carbon black, the higher the difference. The air-permeability of NR filled with 50 phr of CSF was less than that of NR filled with 50 phr of HAF, and close to that of IIR. The volume resistivity of NR/CSF or NBR/CSF vulcanizate was obviously lower than that of NR/ACET or NBR/ACET one. Moreover the volume resistivity of vulcanizate decreased with increasing carbon black amount. The electric conductivity of NBR filled with CSF or ACET was better than that of NR.
The air-tightness and conductivity of NR/CSF and NBR/CSF vulcanizates were studied. The results showed that the carbon black bound rubber content of NR or NBR compounds with 50 phr of CSF were higher than those with the same amount of acetylene black(ACET) or high abrasion furnace black(HAF). In addition, the yield strength(Ty) and tensile strength(Tb) of their compounds were also higher than those of the latter, and the more the loading of carbon black, the higher the difference. The air-permeability of NR filled with 50 phr of CSF was less than that of NR filled with 50 phr of HAF, and close to that of IIR. The volume resistivity of NR/CSF or NBR/CSF vulcanizate was obviously lower than that of NR/ACET or NBR/ACET one. Moreover the volume resistivity of vulcanizate decreased with increasing carbon black amount. The electric conductivity of NBR filled with CSF or ACET was better than that of NR.
2003, 20(11): 1120-1122
Abstract:
Europium doped stable and transparent yttria films were prepared by a sol-gel method using Y(NO3)3 and Eu(NO3)3 as raw materials followed by calcinations at 600~900℃. The red-emission Y2O3:Eu thin films were prepared by dip-draw coating technique on the surface of quartz glass and silica glass, respectively. Addition of PVA-124 favoured the formation of the smooth film. The film structures were analyzed by XRD. The excitation spectrum consists of a wide excitation peak between 220 nm to 260 nm, with strengest emission peak at 614 nm.
Europium doped stable and transparent yttria films were prepared by a sol-gel method using Y(NO3)3 and Eu(NO3)3 as raw materials followed by calcinations at 600~900℃. The red-emission Y2O3:Eu thin films were prepared by dip-draw coating technique on the surface of quartz glass and silica glass, respectively. Addition of PVA-124 favoured the formation of the smooth film. The film structures were analyzed by XRD. The excitation spectrum consists of a wide excitation peak between 220 nm to 260 nm, with strengest emission peak at 614 nm.
