Login In
2004 Volume 21 Issue 11
2004, 21(11): 1081-1086
Abstract:
rHSA-heme is the first obtained totally synthesized artificial blood cell substitute. Recombinant albumin associated with synthetic heme has the sufficient capacity to bind and release oxygen molecules under physiological conditions and is practically used in clinical trial with satisfaction. By mixing rHSA-heme with blood in vitro, the concentration of the heme could maintain stable without heme transference. No effect was confirmed on the number of the blood cells, the morphology of the red blood cells and the blood coagulation system. All the rats were survived by injection of rHSA-heme solutions after the hemodilution and hemorrhage, and nearly all the physiological response parameters could be recovered. The safety experiments have also proved that the rHSA-heme solution has no poisonous effect on the function of the rats. rHSA-heme is hope fully to be a new generation of the artificial red blood cell substitute.
rHSA-heme is the first obtained totally synthesized artificial blood cell substitute. Recombinant albumin associated with synthetic heme has the sufficient capacity to bind and release oxygen molecules under physiological conditions and is practically used in clinical trial with satisfaction. By mixing rHSA-heme with blood in vitro, the concentration of the heme could maintain stable without heme transference. No effect was confirmed on the number of the blood cells, the morphology of the red blood cells and the blood coagulation system. All the rats were survived by injection of rHSA-heme solutions after the hemodilution and hemorrhage, and nearly all the physiological response parameters could be recovered. The safety experiments have also proved that the rHSA-heme solution has no poisonous effect on the function of the rats. rHSA-heme is hope fully to be a new generation of the artificial red blood cell substitute.
2004, 21(11): 1087-1092
Abstract:
Recent studies on the immobilization of nanosized TiO2 photocatalysts are introduced and the applications of supported-photocatalyst TiO2 in environmental conservation, health care and military chemical defence are reviewed. Some problems in the studies are presented and discussed, and it is suggested that the enhancement of technology of TiO2 immobilization and the combination of photocatalytic technology with other technology are the main way to expand the application field of TiO2 photocatalyst.
Recent studies on the immobilization of nanosized TiO2 photocatalysts are introduced and the applications of supported-photocatalyst TiO2 in environmental conservation, health care and military chemical defence are reviewed. Some problems in the studies are presented and discussed, and it is suggested that the enhancement of technology of TiO2 immobilization and the combination of photocatalytic technology with other technology are the main way to expand the application field of TiO2 photocatalyst.
2004, 21(11): 1093-1096
Abstract:
In a solution of 0.05 mol/L KCl-1.1×10-2 mol/L KIO3 supporting electrolyte, tropicamide was found to yield a parallel catalytic hydrogen wave with a peak potential of 1.79 V(vs.SCE). The second-order derivative peak current of the wave is proportional to the tropicamide concentration in the range of 6.0×10-8~8.0×10-5 mol/L with detection limit 3×10-8 mol/L. The analytical sensitivity of the parallel catalytic hydrogen wave is one order of magnitude higher than that of the corresponding catalytic hydrogen wave. The proposed method was applied to the direct determination of the tropicamide in eye drops without previous treatment. The mechanism of the parallel catalytic hydrogen wave in the presence of KIO3 was discussed.
In a solution of 0.05 mol/L KCl-1.1×10-2 mol/L KIO3 supporting electrolyte, tropicamide was found to yield a parallel catalytic hydrogen wave with a peak potential of 1.79 V(vs.SCE). The second-order derivative peak current of the wave is proportional to the tropicamide concentration in the range of 6.0×10-8~8.0×10-5 mol/L with detection limit 3×10-8 mol/L. The analytical sensitivity of the parallel catalytic hydrogen wave is one order of magnitude higher than that of the corresponding catalytic hydrogen wave. The proposed method was applied to the direct determination of the tropicamide in eye drops without previous treatment. The mechanism of the parallel catalytic hydrogen wave in the presence of KIO3 was discussed.
2004, 21(11): 1097-1100
Abstract:
Three solid complexes Re[B(Ssal)2]·nH2O(Re=La(Ⅲ),Nd(Ⅲ),Sm(Ⅲ), [B(Ssal)2]3-=bis(sulfosalicyl)borate anion, n=4,6) were synthesized in aqueous solution and characterized by elemental analysis, sulfosalicylic acid content analysis, IR, 1H NMR, TG-DTA and molar conductivity measurements. The protection effect of samaric chloride, sulfosalicylic acid, boric acid and Sm[B(Ssal)2]·6H2O on lip membrane damage of dried up wheat seedling leaf were compared. The results showed sulfosalicylic acid (H3Ssal) and Sm[B(Ssal)2]·6H2O have certain protection effect, making the malonaldehyde content decreased by 55% and 64%, and the SOD activity increased by 49% and 61%, respectively.
Three solid complexes Re[B(Ssal)2]·nH2O(Re=La(Ⅲ),Nd(Ⅲ),Sm(Ⅲ), [B(Ssal)2]3-=bis(sulfosalicyl)borate anion, n=4,6) were synthesized in aqueous solution and characterized by elemental analysis, sulfosalicylic acid content analysis, IR, 1H NMR, TG-DTA and molar conductivity measurements. The protection effect of samaric chloride, sulfosalicylic acid, boric acid and Sm[B(Ssal)2]·6H2O on lip membrane damage of dried up wheat seedling leaf were compared. The results showed sulfosalicylic acid (H3Ssal) and Sm[B(Ssal)2]·6H2O have certain protection effect, making the malonaldehyde content decreased by 55% and 64%, and the SOD activity increased by 49% and 61%, respectively.
2004, 21(11): 1101-1104
Abstract:
A new electroactive polynuclear inorganic compound of rare earth metal hexacyanoferrate, samarium hexacyanoferrate(SmHCF), was prepared by electrochemical deposition of SmHCF on the surface of a glassy carbon electrode via a potential cycling procedure. The result of SEM indicates that SmHCF was adhered on the surface of the electrode in the form of particles, the average size of SmHCF was about (11.3±1.3) μm. In FTIR spectrum of SmHCF a very strong and sharp peak at 2 061.5 cm-1 corresponding to the stretching vibration of the C-N group in the SmHCF was observed. The cyclic voltammetric results indicate SmHCF/GC electrode exhibited a pair of well defined and nearly symmetrical redox peaks. The anodic and cathodic peak potentials were 207 mV and 171 mV, respectively, and the formal potential(E0') was 189 mV at a scan rate of 20 mV/s. The redox peak shifted in the positive direction with the increasing of the concentration of supporting electrolyte and the formal potential increased linearly with the concentration of supporting electrolyte(log c) with a slope of 50.4 mV. The experimental results indicate that SmHCF modified GC electrode showed an electrocatalytic activity in the oxidation of dopamine(DA), the electrocatalytic current increased with the increasing of the concentration of DA. In the range of 1.0 to 15.0 mmol/L, the electro-catalytic current increased linearly with the concentration.
A new electroactive polynuclear inorganic compound of rare earth metal hexacyanoferrate, samarium hexacyanoferrate(SmHCF), was prepared by electrochemical deposition of SmHCF on the surface of a glassy carbon electrode via a potential cycling procedure. The result of SEM indicates that SmHCF was adhered on the surface of the electrode in the form of particles, the average size of SmHCF was about (11.3±1.3) μm. In FTIR spectrum of SmHCF a very strong and sharp peak at 2 061.5 cm-1 corresponding to the stretching vibration of the C-N group in the SmHCF was observed. The cyclic voltammetric results indicate SmHCF/GC electrode exhibited a pair of well defined and nearly symmetrical redox peaks. The anodic and cathodic peak potentials were 207 mV and 171 mV, respectively, and the formal potential(E0') was 189 mV at a scan rate of 20 mV/s. The redox peak shifted in the positive direction with the increasing of the concentration of supporting electrolyte and the formal potential increased linearly with the concentration of supporting electrolyte(log c) with a slope of 50.4 mV. The experimental results indicate that SmHCF modified GC electrode showed an electrocatalytic activity in the oxidation of dopamine(DA), the electrocatalytic current increased with the increasing of the concentration of DA. In the range of 1.0 to 15.0 mmol/L, the electro-catalytic current increased linearly with the concentration.
2004, 21(11): 1105-1108
Abstract:
Ten novel Schiff bases of imidazolinone were synthesized. Vinyliminophosphorane reacted with carbon disulfide and hydrazine hydrate via tandem aza-Witting reactions to give 3-amino-2-thio-4-imidazolidinones 4. In the presence of potassium carbonate, iodomethane reacted with 3-amino-2-thio-4-imidazolidinones 4 to give 3-amino-5-benzylidene-2-methylthio-imidazolin-4-one 5, which condensed with arylaldehydes to give 3-benzylimino-2-methylthio-5-benzylidene imidazolin-4-one 6. The structures of compounds 6 were confirmed by elemental analysis, 1H NMR, IR and MS. The preliminary biological tests show that most of compounds 6 have good herbicidal activities to monocotyledon Barnyard grass and dicotyledon Cole. Compound 6h, 2-methylthio-5-benzylidene-3-(3'-chloro-benzyl)-imino-imidazoli-4-one exhibits 100% inhibition against Cole root and stalk, Barnyard grass root in 100 mg/L.
Ten novel Schiff bases of imidazolinone were synthesized. Vinyliminophosphorane reacted with carbon disulfide and hydrazine hydrate via tandem aza-Witting reactions to give 3-amino-2-thio-4-imidazolidinones 4. In the presence of potassium carbonate, iodomethane reacted with 3-amino-2-thio-4-imidazolidinones 4 to give 3-amino-5-benzylidene-2-methylthio-imidazolin-4-one 5, which condensed with arylaldehydes to give 3-benzylimino-2-methylthio-5-benzylidene imidazolin-4-one 6. The structures of compounds 6 were confirmed by elemental analysis, 1H NMR, IR and MS. The preliminary biological tests show that most of compounds 6 have good herbicidal activities to monocotyledon Barnyard grass and dicotyledon Cole. Compound 6h, 2-methylthio-5-benzylidene-3-(3'-chloro-benzyl)-imino-imidazoli-4-one exhibits 100% inhibition against Cole root and stalk, Barnyard grass root in 100 mg/L.
2004, 21(11): 1109-1112
Abstract:
Nanometer titanium dioxide was prepared by coating technique and characterized by XRD and SEM(anatase, average size 22.7 nanometer). The experiment of the photocatalytic killing human gastric cancer cell line was conducted in vitro with titanium dioxide as a photocatalyst. The viability of the cancer cells was detected by a flow cytometer(FCM) and fluorescence staining method. The results showed that human gastric cancer cell line BGC-823 were remarkbly killed by the photocatalytic oxidetion reaction under irradiation of 300~400nm UV light. 80% of the cells were killed when the irradiation intensity was 1.06×10-3 W/cm2, with 9.8×10-7 g/cm2 TiO2 coated as a photocatalyst, and 40 min irradiation time.
Nanometer titanium dioxide was prepared by coating technique and characterized by XRD and SEM(anatase, average size 22.7 nanometer). The experiment of the photocatalytic killing human gastric cancer cell line was conducted in vitro with titanium dioxide as a photocatalyst. The viability of the cancer cells was detected by a flow cytometer(FCM) and fluorescence staining method. The results showed that human gastric cancer cell line BGC-823 were remarkbly killed by the photocatalytic oxidetion reaction under irradiation of 300~400nm UV light. 80% of the cells were killed when the irradiation intensity was 1.06×10-3 W/cm2, with 9.8×10-7 g/cm2 TiO2 coated as a photocatalyst, and 40 min irradiation time.
2004, 21(11): 1113-1117
Abstract:
Intermolecular compound (Hdmpy)11H(H2W12O40)2·6H2O was prepared by the reaction of sodium tungstate dihydrate with 2,6-dimethyl pyridine(dmpy) and characterized by IR, UV spectroscopy and single crystal X-ray diffraction. The crystal parameters of the compound are as follows: monoclinic, P21/c space group, a=2.162 8(4), b=2.156 8(4), c=2.918 3(6) nm, β=92.92(3)°, V=13.596(5) nm3, Z=4, Dc=3.418 Mg/m3, R=0.056 5, wR=0.100 8. The crystal structure analysis reveals that the electrostatic and intermolecular interactions between protonated 2,6-dimethyl pyridine molecules and the polyanions form an infinite two dimensional network by means of W-O-H-N or W-O-H-C. Cyclic voltammetric curves of the polyoxoanion of the title compound in a 0.5 mol/L NaCl-HCl solution reveals the two-step one-electron reduction process.
Intermolecular compound (Hdmpy)11H(H2W12O40)2·6H2O was prepared by the reaction of sodium tungstate dihydrate with 2,6-dimethyl pyridine(dmpy) and characterized by IR, UV spectroscopy and single crystal X-ray diffraction. The crystal parameters of the compound are as follows: monoclinic, P21/c space group, a=2.162 8(4), b=2.156 8(4), c=2.918 3(6) nm, β=92.92(3)°, V=13.596(5) nm3, Z=4, Dc=3.418 Mg/m3, R=0.056 5, wR=0.100 8. The crystal structure analysis reveals that the electrostatic and intermolecular interactions between protonated 2,6-dimethyl pyridine molecules and the polyanions form an infinite two dimensional network by means of W-O-H-N or W-O-H-C. Cyclic voltammetric curves of the polyoxoanion of the title compound in a 0.5 mol/L NaCl-HCl solution reveals the two-step one-electron reduction process.
2004, 21(11): 1118-1122
Abstract:
The kinetics of acrylamide(AAM) polymerization initiated by 4,4'-azobis-(4-cyanopentanoyl(p-dimethylamino)anilide)(ACPDA)/dibenzoyl peroxide(BPO) redox system was studied in N,N-dimethylformamide. The effects of concentrations of the monomer, ACPDA, BPO and the temperature on the polymerization rate were studied. The reaction order and the activation energy were determined. The results indicate that the polymerization rate increases with increasing the concentrations of monomer, ACPDA, BPO as well as the reaction temperature. The system has the characteristic of a redox initiation system. The equation of the polymerization rate is Rp=K[BPO]0.73[ACPDA]0.54[AAM]1.53 with an apparent activation energy of 38.2 kJ/mol for AAM polymerization.
The kinetics of acrylamide(AAM) polymerization initiated by 4,4'-azobis-(4-cyanopentanoyl(p-dimethylamino)anilide)(ACPDA)/dibenzoyl peroxide(BPO) redox system was studied in N,N-dimethylformamide. The effects of concentrations of the monomer, ACPDA, BPO and the temperature on the polymerization rate were studied. The reaction order and the activation energy were determined. The results indicate that the polymerization rate increases with increasing the concentrations of monomer, ACPDA, BPO as well as the reaction temperature. The system has the characteristic of a redox initiation system. The equation of the polymerization rate is Rp=K[BPO]0.73[ACPDA]0.54[AAM]1.53 with an apparent activation energy of 38.2 kJ/mol for AAM polymerization.
2004, 21(11): 1123-1126
Abstract:
A dihydroxyl compound with ketonic moiety was synthesized by the Michael reaction between diethanolamine and diacetone acrylamide. The compound could be used as a crosslinker for waterborne polyurethane. The reaction process was studied by FT-IR, the optimal reaction conditions were n(DEA): n(DAAM)=1:1.01 at 80℃ for 8 h. The structure of the crosslinker was characterized by FT-IR and NMR. The molecular weight of the crosslinker was determined by MS. The crosslinking reaction between ketone and hydrazide during the film forming stage was monitored by FT-IR. It has shown that the crosslinking reaction occurs in the system containing volatile base(such as triethylamine) or in the acid system, but it can't take place in the system containing non-volatile base(such as sodium hydroxide).
A dihydroxyl compound with ketonic moiety was synthesized by the Michael reaction between diethanolamine and diacetone acrylamide. The compound could be used as a crosslinker for waterborne polyurethane. The reaction process was studied by FT-IR, the optimal reaction conditions were n(DEA): n(DAAM)=1:1.01 at 80℃ for 8 h. The structure of the crosslinker was characterized by FT-IR and NMR. The molecular weight of the crosslinker was determined by MS. The crosslinking reaction between ketone and hydrazide during the film forming stage was monitored by FT-IR. It has shown that the crosslinking reaction occurs in the system containing volatile base(such as triethylamine) or in the acid system, but it can't take place in the system containing non-volatile base(such as sodium hydroxide).
2004, 21(11): 1127-1131
Abstract:
The transport of cobalt(Ⅱ) from an aqueous 1.0 mol/L HAc-NaAc(pH=5.8~6.0) feed solution into a stripping solution 0.33 mol/L H2SO4 through a supported liquid membrane(SLM) consisting of bis(2-ethylhexyl) phosphinic acid(BEHPA) in CHCl3 on the microporous polypropylene film were studied. The stoichiometry of the extracted species of cobalt(Ⅱ) by BEHPA were determined. The liquid-liquid extraction is carried out by the following equation:Co2++6HR=CoR2·4HR+2H+,Kex=3.89×10-8 where HR represents BEHPA. The effects of pH value in feed solution, concentration of BEHPA in the membrane, experimental temperature and initial concentration of Co(Ⅱ) in the feed on the transport rate of Co(Ⅱ) were investigated. The transport kinetic equation is derived in terms of the law of mass diffusion and the interface chemistry. The thickness of aqueous diffusion layer(δa) and diffusion coefficient(d0) of Co(Ⅱ) through SLM were evaluated, by the linear slope method, to be 7.73×10-6 m and 5.69×10-10 m2/s, respectively.
The transport of cobalt(Ⅱ) from an aqueous 1.0 mol/L HAc-NaAc(pH=5.8~6.0) feed solution into a stripping solution 0.33 mol/L H2SO4 through a supported liquid membrane(SLM) consisting of bis(2-ethylhexyl) phosphinic acid(BEHPA) in CHCl3 on the microporous polypropylene film were studied. The stoichiometry of the extracted species of cobalt(Ⅱ) by BEHPA were determined. The liquid-liquid extraction is carried out by the following equation:Co2++6HR=CoR2·4HR+2H+,Kex=3.89×10-8 where HR represents BEHPA. The effects of pH value in feed solution, concentration of BEHPA in the membrane, experimental temperature and initial concentration of Co(Ⅱ) in the feed on the transport rate of Co(Ⅱ) were investigated. The transport kinetic equation is derived in terms of the law of mass diffusion and the interface chemistry. The thickness of aqueous diffusion layer(δa) and diffusion coefficient(d0) of Co(Ⅱ) through SLM were evaluated, by the linear slope method, to be 7.73×10-6 m and 5.69×10-10 m2/s, respectively.
2004, 21(11): 1132-1135
Abstract:
Poly(acrylic acid) was hydrophobically modified with octadecyl acrylate in supercritical carbon dioxide. The copolymer obtained was white solid powder uniformly sized in about 0.2 μm as observed by SEM. The ratio of acrylic acid to octadecyl acrylate in the product by acid and base titration was found to be the same as the feed ratio. The solution viscosity of the copolymer dramatically increased with increase in pH value, and the solution of the hydrophobiclly modified poly(acrylic acid) showed good salt resistance.
Poly(acrylic acid) was hydrophobically modified with octadecyl acrylate in supercritical carbon dioxide. The copolymer obtained was white solid powder uniformly sized in about 0.2 μm as observed by SEM. The ratio of acrylic acid to octadecyl acrylate in the product by acid and base titration was found to be the same as the feed ratio. The solution viscosity of the copolymer dramatically increased with increase in pH value, and the solution of the hydrophobiclly modified poly(acrylic acid) showed good salt resistance.
2004, 21(11): 1136-1140
Abstract:
The alanine Schiff base Mn(Ⅲ) complex(Sal-Ala-Mn) was synthesized from Mn(OAC)2 and the ligand obtained from the reaction of alanine with salicylaldehyde. The effects of reaction temperature and time, amounts of catalyst and isobutylaldehyde, volume of solvent on the aerobic epoxidation of cyclohexene were studied. The conversion of cyclohexene was 98.3% with a selectivity of 70.6% of cyclohexene epoxide when 2.5 mL of cyclohexene, 0.1 mmol of catalyst, 4.5 mL of isobutylaldehyde and 60 mL of acetonitrile were charged, and the reaction was run at 35℃ for 10 h.
The alanine Schiff base Mn(Ⅲ) complex(Sal-Ala-Mn) was synthesized from Mn(OAC)2 and the ligand obtained from the reaction of alanine with salicylaldehyde. The effects of reaction temperature and time, amounts of catalyst and isobutylaldehyde, volume of solvent on the aerobic epoxidation of cyclohexene were studied. The conversion of cyclohexene was 98.3% with a selectivity of 70.6% of cyclohexene epoxide when 2.5 mL of cyclohexene, 0.1 mmol of catalyst, 4.5 mL of isobutylaldehyde and 60 mL of acetonitrile were charged, and the reaction was run at 35℃ for 10 h.
2004, 21(11): 1141-1144
Abstract:
The influences of trace materials on the liberation of PH3 from red phosphorus and the way to slow down the liberation have been studied by headspace gas chromatography and accelerated aging tests. It has been found that the liberation of PH3 from commercial red phosphorus is mainly due to its reaction with water. Trace amount of metal ions such as iron, copper, nickel and chromium greatly affected the liberation of PH3. It is found that addition of 1%(mass fraction) nano-magnesium hydroxide can slow down the PH3 liberation significantly and result in a yield of less than 0.4 mg/(m3·d) from the oven-dried red phosphorus, without changing the dispersibility and fluidity of the phosphorus.
The influences of trace materials on the liberation of PH3 from red phosphorus and the way to slow down the liberation have been studied by headspace gas chromatography and accelerated aging tests. It has been found that the liberation of PH3 from commercial red phosphorus is mainly due to its reaction with water. Trace amount of metal ions such as iron, copper, nickel and chromium greatly affected the liberation of PH3. It is found that addition of 1%(mass fraction) nano-magnesium hydroxide can slow down the PH3 liberation significantly and result in a yield of less than 0.4 mg/(m3·d) from the oven-dried red phosphorus, without changing the dispersibility and fluidity of the phosphorus.
2004, 21(11): 1145-1149
Abstract:
An optical chemical sensor has been developed to detect sulfite based on reversible fluorescence quenching of tetraphenylporphyrin(TPP)/2,6-di-o-isobutyl-β-cyclodextrin(DOB-β-CD) immobilized in a plasticized poly(vinyl chloride)(PVC) membrane. The optimum sensor membrane consists of 50 mg of PVC, 100 mg of bis(2-ethytbexyl) sebacate(BOS), 2.5 mg of TPP and 10 mg of DOB-β-CD. The maximum response of the optode memberane for sulfite was obtained in a KOH-KH2PO4 buffer solution of pH=6.5. The sensor responds linearly to sulfite in the concentration ranged in 6.22×10-6 to 3.11×10-4 mol/L, with a detection limit of 7.80×10-7 mol/L. The response time of the sensor is less than 40 s. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity. Some common anions, cations and foreign substances do not interfere with the sulfite detection. It has been applied in direct determination of sulfite in a sample of industrial waste water with satisfactory result.
An optical chemical sensor has been developed to detect sulfite based on reversible fluorescence quenching of tetraphenylporphyrin(TPP)/2,6-di-o-isobutyl-β-cyclodextrin(DOB-β-CD) immobilized in a plasticized poly(vinyl chloride)(PVC) membrane. The optimum sensor membrane consists of 50 mg of PVC, 100 mg of bis(2-ethytbexyl) sebacate(BOS), 2.5 mg of TPP and 10 mg of DOB-β-CD. The maximum response of the optode memberane for sulfite was obtained in a KOH-KH2PO4 buffer solution of pH=6.5. The sensor responds linearly to sulfite in the concentration ranged in 6.22×10-6 to 3.11×10-4 mol/L, with a detection limit of 7.80×10-7 mol/L. The response time of the sensor is less than 40 s. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity. Some common anions, cations and foreign substances do not interfere with the sulfite detection. It has been applied in direct determination of sulfite in a sample of industrial waste water with satisfactory result.
2004, 21(11): 1150-1154
Abstract:
Composite oxides Nd2-xSrxCoO4(0.4≤x≤1.2) and LnSrCoO4(Ln=Pr,Nd,Eu) were synthesized by the citric-acid complexation method. The results of XRD indicate that the composite oxides have K2NiF4 structure. Other phases were formed when x=0.4 and x=1.2. Different influences of Nd, Pr, Eu on the activities of LnSrCoO4 in CO oxidation and C3H8 oxidation were observed. The oxidative activities, average crystalline size and lattice distortion of Nd2-xSrxCoO4 are increased with the increase of coefficient x. When x>0.8, the lattice distortion is reduced with the increase of coefficient x. The results of O2-TPD show that the desorption amount of lattice oxygen over Nd2-xSrxCoO4 increases with x, however, the amount of the chemidesorption oxygen decreases. In the H2-TPR curves of Nd2-xSrxCoO4, with the increase of coefficient x, the peak temperatures of high temperature reduction increase, however, the peak temperatures of low temperature reduction decrease, indicating that the activity of lattice oxygen and thermal stability of Nd2-xSrxCoO4 increase with x.
Composite oxides Nd2-xSrxCoO4(0.4≤x≤1.2) and LnSrCoO4(Ln=Pr,Nd,Eu) were synthesized by the citric-acid complexation method. The results of XRD indicate that the composite oxides have K2NiF4 structure. Other phases were formed when x=0.4 and x=1.2. Different influences of Nd, Pr, Eu on the activities of LnSrCoO4 in CO oxidation and C3H8 oxidation were observed. The oxidative activities, average crystalline size and lattice distortion of Nd2-xSrxCoO4 are increased with the increase of coefficient x. When x>0.8, the lattice distortion is reduced with the increase of coefficient x. The results of O2-TPD show that the desorption amount of lattice oxygen over Nd2-xSrxCoO4 increases with x, however, the amount of the chemidesorption oxygen decreases. In the H2-TPR curves of Nd2-xSrxCoO4, with the increase of coefficient x, the peak temperatures of high temperature reduction increase, however, the peak temperatures of low temperature reduction decrease, indicating that the activity of lattice oxygen and thermal stability of Nd2-xSrxCoO4 increase with x.
2004, 21(11): 1155-1159
Abstract:
Multi-block copolymer poly(p-phenylene vinylene-co-poly(ethylene oxide))(PPVEO200 and PPVEO600) was synthesized by Wittig reaction. PPVEO600 showed better thermal and electroluminscence properties than PPVEO200, and the aggregated structure of PPVEO600 was reticulated through physical crosslinking point. PPVEO600 exhibits a glass transition temperature of -46.3℃, and shows high conductivity after electrochemically doped with LiClO4. The LEC device (ITO/PPVEO600(LiClO4)/Au) was fabricated, which showed a turn-on voltage at 2.6 V for both current and light emission. The maximum electroluminescence (EL) efficiency of the LECs device was 2.13 cd/A at 3.2 V.
Multi-block copolymer poly(p-phenylene vinylene-co-poly(ethylene oxide))(PPVEO200 and PPVEO600) was synthesized by Wittig reaction. PPVEO600 showed better thermal and electroluminscence properties than PPVEO200, and the aggregated structure of PPVEO600 was reticulated through physical crosslinking point. PPVEO600 exhibits a glass transition temperature of -46.3℃, and shows high conductivity after electrochemically doped with LiClO4. The LEC device (ITO/PPVEO600(LiClO4)/Au) was fabricated, which showed a turn-on voltage at 2.6 V for both current and light emission. The maximum electroluminescence (EL) efficiency of the LECs device was 2.13 cd/A at 3.2 V.
2004, 21(11): 1160-1164
Abstract:
A kind of composite P(VDF-HFP)-based polymer films with miro-porous structure, which were filled with various amounts of Al2O3 nanoparticles, were prepared by a phase inversion technology. The porosity of the composite polymer films filled with 6%(mass fraction) Al2O3 nanoparticles is 40% higher than that of the polymer films without Al2O3 nanoparticles. The resulting gel polymer electrolyte possesses an ionic conductivity of 1.47×10-3 S/cm and the ionic transference number of 0.72. The characteristics of the interface between the surface of lithium metal and the polymer electrolytes, which were filled with and without Al2O3 nanoparticles, were investigated by ac impedance technology.
A kind of composite P(VDF-HFP)-based polymer films with miro-porous structure, which were filled with various amounts of Al2O3 nanoparticles, were prepared by a phase inversion technology. The porosity of the composite polymer films filled with 6%(mass fraction) Al2O3 nanoparticles is 40% higher than that of the polymer films without Al2O3 nanoparticles. The resulting gel polymer electrolyte possesses an ionic conductivity of 1.47×10-3 S/cm and the ionic transference number of 0.72. The characteristics of the interface between the surface of lithium metal and the polymer electrolytes, which were filled with and without Al2O3 nanoparticles, were investigated by ac impedance technology.
2004, 21(11): 1165-1168
Abstract:
Amination of dimethylbicyclolactam 1 gives dimethyl-bicyclolactam-lactone 2, which transfers to cyanopyrolidones 3a and 3b through substitutive ring-opening reactions by action of hydrocyanic acid and esterification with diazomethane. Sulfidizations of 3a and 3b give the end products, cyanopyrrolidinylthiones 4a and 4b, with total yield of ca. 59%. The trans- and cis-isomeric products were isolated by HPLC in mass fraction of 64.5% and 34.0%, respectively. Their structures were confirmed by elemental analysis, UV-Vis, IR, 1H NMR,13C NMR and MS spectra.
Amination of dimethylbicyclolactam 1 gives dimethyl-bicyclolactam-lactone 2, which transfers to cyanopyrolidones 3a and 3b through substitutive ring-opening reactions by action of hydrocyanic acid and esterification with diazomethane. Sulfidizations of 3a and 3b give the end products, cyanopyrrolidinylthiones 4a and 4b, with total yield of ca. 59%. The trans- and cis-isomeric products were isolated by HPLC in mass fraction of 64.5% and 34.0%, respectively. Their structures were confirmed by elemental analysis, UV-Vis, IR, 1H NMR,13C NMR and MS spectra.
2004, 21(11): 1169-1173
Abstract:
A-type 2 400 mA·h nickel metal hydride batteries with high-rated discharge performance were prepared. The discharge performance of the battery was improved by using an end-face welded current collector and optimizing the electrode thickness, separator material and electrolyte composition. In addition, its charge performance at a high charge current was increased through addition of additives in the nickel electrode. The test results show that the batteries have a low internal resistance and good charge/discharge performance, and their cycle life is above 300 cycles. The discharge capacity is above 2 300 mA·h at 10C rate and the 2C rate charge efficiency vs 0.2C is above 95%. The batteries can be used under high charge/discharge current conditions.
A-type 2 400 mA·h nickel metal hydride batteries with high-rated discharge performance were prepared. The discharge performance of the battery was improved by using an end-face welded current collector and optimizing the electrode thickness, separator material and electrolyte composition. In addition, its charge performance at a high charge current was increased through addition of additives in the nickel electrode. The test results show that the batteries have a low internal resistance and good charge/discharge performance, and their cycle life is above 300 cycles. The discharge capacity is above 2 300 mA·h at 10C rate and the 2C rate charge efficiency vs 0.2C is above 95%. The batteries can be used under high charge/discharge current conditions.
2004, 21(11): 1174-1177
Abstract:
The solvation number of lithium cation and ion association of lithium nitrate in N,N-dimethylformamide(DMF) have been investigated by ATR-FTIR spectroscopy. Splittings of O=C-N deformation and shift of carbonyl stretching band of DMF suggest that there is a strong interaction between oxygen atoms of DMF and lithium cations. The solvation numbers of lithium ion have been calculated quantitatively based on these facts. The band fitting for the ν2(NO-out-of-plane bending) band of the NO3- shows free anions and contact ionic pairs coexist in the solution.
The solvation number of lithium cation and ion association of lithium nitrate in N,N-dimethylformamide(DMF) have been investigated by ATR-FTIR spectroscopy. Splittings of O=C-N deformation and shift of carbonyl stretching band of DMF suggest that there is a strong interaction between oxygen atoms of DMF and lithium cations. The solvation numbers of lithium ion have been calculated quantitatively based on these facts. The band fitting for the ν2(NO-out-of-plane bending) band of the NO3- shows free anions and contact ionic pairs coexist in the solution.
2004, 21(11): 1178-1180
Abstract:
A mixed precursor was prepared by the solid state reaction of FeCl2·4H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O with NH4HCO3 at ambient temperature. A composite oxide was obtained by decomposing the precursor at 610℃ for 4 hours. The composite oxide was characterized by XRD, SEM, and chemical analysis as well as characterized in size. Fe2Co0.5Ni0.5O5 is a reticular nanometer powder with a radial diameter of about 20 nm and a ratio of average length to average diameter up to about 4. The composite shows stable permittivity ε, magnetic permeability μ and ability of absorbing electromagnetic wave γ.
A mixed precursor was prepared by the solid state reaction of FeCl2·4H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O with NH4HCO3 at ambient temperature. A composite oxide was obtained by decomposing the precursor at 610℃ for 4 hours. The composite oxide was characterized by XRD, SEM, and chemical analysis as well as characterized in size. Fe2Co0.5Ni0.5O5 is a reticular nanometer powder with a radial diameter of about 20 nm and a ratio of average length to average diameter up to about 4. The composite shows stable permittivity ε, magnetic permeability μ and ability of absorbing electromagnetic wave γ.
2004, 21(11): 1181-1183
Abstract:
Supersonic extraction process of glycyrrhizia polysaccharide(GPS) was examined by orthogonal experiments. The optimized supersonic extraction process was obtained and mathematical simulation based on the supersonic extraction was established. The optimized condition for extraction of GPS is as follows: supersonic treatment time is 3.5 h, supersonic treatment temperature is 81℃, liquid-solid ratio is 10 mL/g, number of times of extraction is 1. Under the optimized condition, the extraction rate of GPS is 5.40%, purity is 39.95% and the relative deviation of repeated experiments is 2.54%.
Supersonic extraction process of glycyrrhizia polysaccharide(GPS) was examined by orthogonal experiments. The optimized supersonic extraction process was obtained and mathematical simulation based on the supersonic extraction was established. The optimized condition for extraction of GPS is as follows: supersonic treatment time is 3.5 h, supersonic treatment temperature is 81℃, liquid-solid ratio is 10 mL/g, number of times of extraction is 1. Under the optimized condition, the extraction rate of GPS is 5.40%, purity is 39.95% and the relative deviation of repeated experiments is 2.54%.
2004, 21(11): 1184-1186
Abstract:
4-Nitrophenyl ferulate was synthesized in one-step without the protection of the hydroxyl of ferulic acid in the presence of 1,3-dicyclohexylcarbodiimide(DCC) as the catalyst. Thus, 15.20 g of ferulic acid reacted with 18.07 g of 4-nitrophenol for 24 h at room temperature in the presence of 22.44 g of DCC. The crude product was recrystallized from CHCl3 to give 16.00 g of 4-nitrophenyl ferulate and the yield was 82.5%. Elemental analysis, IR and 1H NMR techniques were used to prove the structure of the product.
4-Nitrophenyl ferulate was synthesized in one-step without the protection of the hydroxyl of ferulic acid in the presence of 1,3-dicyclohexylcarbodiimide(DCC) as the catalyst. Thus, 15.20 g of ferulic acid reacted with 18.07 g of 4-nitrophenol for 24 h at room temperature in the presence of 22.44 g of DCC. The crude product was recrystallized from CHCl3 to give 16.00 g of 4-nitrophenyl ferulate and the yield was 82.5%. Elemental analysis, IR and 1H NMR techniques were used to prove the structure of the product.
2004, 21(11): 1187-1189
Abstract:
Phenothalein-deoxyribonucleic acid(DNA)-cetyltrimethyl ammonium bromide(CTMAB) system has been studied by resonance light-scattering(RLS). In Tris-HCl buffer solution(pH=9.30), phenothalein and DNA react with CTMAB to form large particles of ion-association complex, which results in significant enhancement of RLS intensity. The spectral characteristics of RLS, the effective factors and optimum conditions of the reaction have been investigated. Under optimum conditions, the enhanced RLS intensity was proportional to the concentration of DNA in the range of 0.04 to 0.8 mg/L for fish sperm DNA(fsDNA) and 0.03 to 2.5 mg/L for calf thymus DNA(ctDNA). The detection limits were 12.0 μg/L and 17.0 μg/L for fsDNA and ctDNA, respectively.
Phenothalein-deoxyribonucleic acid(DNA)-cetyltrimethyl ammonium bromide(CTMAB) system has been studied by resonance light-scattering(RLS). In Tris-HCl buffer solution(pH=9.30), phenothalein and DNA react with CTMAB to form large particles of ion-association complex, which results in significant enhancement of RLS intensity. The spectral characteristics of RLS, the effective factors and optimum conditions of the reaction have been investigated. Under optimum conditions, the enhanced RLS intensity was proportional to the concentration of DNA in the range of 0.04 to 0.8 mg/L for fish sperm DNA(fsDNA) and 0.03 to 2.5 mg/L for calf thymus DNA(ctDNA). The detection limits were 12.0 μg/L and 17.0 μg/L for fsDNA and ctDNA, respectively.
2004, 21(11): 1190-1192
Abstract:
A high bioactive flavonol veronicafolin was obtained from a Tibetan medicine Chrysosplenium nudicaule Bunge. The supermolecular solubilization of β-cyclodextrin(β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) on the flavonol has been investigated by a phase solubility method. The results revealed the formation of 1:1 inclusion complex between flavonol and HP-β-CD dramatically increased the solubility of the flavonol, whereas β-CD decreased its solublility. The complex constant Kf for HP-β-CD and flavonol is 4.5×106 L/mol.
A high bioactive flavonol veronicafolin was obtained from a Tibetan medicine Chrysosplenium nudicaule Bunge. The supermolecular solubilization of β-cyclodextrin(β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) on the flavonol has been investigated by a phase solubility method. The results revealed the formation of 1:1 inclusion complex between flavonol and HP-β-CD dramatically increased the solubility of the flavonol, whereas β-CD decreased its solublility. The complex constant Kf for HP-β-CD and flavonol is 4.5×106 L/mol.
2004, 21(11): 1193-1195
Abstract:
Biodegradable Poly(hexylene-sebacate)-co-(hexylene-adipate) with high intrinsic viscosity was synthesized by one-pot polycondensation of sebacic acid and adipic acid with 1,6-hexylenediol in a yield of 96%. The chemical structure of the copolymer was characterized by FTIR and 1H NMR. The DSC result shows that the melting point and crystallization temperature of the copolymer decreased with the increase in HA content, and both exhibit the minimum values while x(HA) reachs 60%. It was also found by TG that PHA in the copolymer was easier decomposed, but no effect on the thermal decomposition of PHSe was observed on the copolymerization.
Biodegradable Poly(hexylene-sebacate)-co-(hexylene-adipate) with high intrinsic viscosity was synthesized by one-pot polycondensation of sebacic acid and adipic acid with 1,6-hexylenediol in a yield of 96%. The chemical structure of the copolymer was characterized by FTIR and 1H NMR. The DSC result shows that the melting point and crystallization temperature of the copolymer decreased with the increase in HA content, and both exhibit the minimum values while x(HA) reachs 60%. It was also found by TG that PHA in the copolymer was easier decomposed, but no effect on the thermal decomposition of PHSe was observed on the copolymerization.
2004, 21(11): 1196-1198
Abstract:
A ternary co-polysilane was synthesized by the Wurtz-type coupling reaction and characterized by FI-IR, XRD, TEM, UV and fluorescence spectroscopy. The results show the copolysilane is amorphous and partly ordered in structure. The TEM image indicates the copolysilane possesses a rodlike structure. It decomposes at temperature near 300℃, has a better thermal stability than polymers with -C-C- main chain. The UV spectrum of the copolysilane displays a strong and broad absorption range. It emits strong fluorescence at 420 nm and could be a kind of promising photoluminescence material.
A ternary co-polysilane was synthesized by the Wurtz-type coupling reaction and characterized by FI-IR, XRD, TEM, UV and fluorescence spectroscopy. The results show the copolysilane is amorphous and partly ordered in structure. The TEM image indicates the copolysilane possesses a rodlike structure. It decomposes at temperature near 300℃, has a better thermal stability than polymers with -C-C- main chain. The UV spectrum of the copolysilane displays a strong and broad absorption range. It emits strong fluorescence at 420 nm and could be a kind of promising photoluminescence material.
2004, 21(11): 1199-1201
Abstract:
The effects of type and amount of chain extenders, hydroxyl terminated polybutadiene(HTPB) of different molecular weights and filler on the hydrolytic stability of polybutadiene based polyurethane elastomer were studied. The results showed that the stability of HTPB-PU was improved by addition of chain extenders, especially butanediol and 1,6-hexanediol. The more the amount of the extender, and the lower the molecular weight of HTPB, the higher the hydrolytic stability. The stability of HTPB-PU could be improved also by addition of inorganic fillers.
The effects of type and amount of chain extenders, hydroxyl terminated polybutadiene(HTPB) of different molecular weights and filler on the hydrolytic stability of polybutadiene based polyurethane elastomer were studied. The results showed that the stability of HTPB-PU was improved by addition of chain extenders, especially butanediol and 1,6-hexanediol. The more the amount of the extender, and the lower the molecular weight of HTPB, the higher the hydrolytic stability. The stability of HTPB-PU could be improved also by addition of inorganic fillers.
2004, 21(11): 1202-1204
Abstract:
A self-made polyurethane reactive emulsifier(abbreviated to PURE) was applied in the emulsion copolymerization of methyl methacrylate(MMA) and butyl acrylate(BA). The morphology of the latex particles, water resistance, adhesion capacity, tensile shear strength and thermal stability of the copolymers were investigated. The copolymer latexes obtained in the presence of PURE are consisted of monodispersed latex particles with a diameter of ca. 0.2 μm. Experimental results show that the latex films obtained possess adhesion capacity in grade 1 and tensile shear strength of τ=3.43 MPa, better than that of the common latex film. Their water-absorption rate and water-dissolving rate are only 46.4%and 19.6%, respectively, of those of the common latex films. But the thermal stability of the emulsifier-free latex films is lower than that of the common copolymer film.
A self-made polyurethane reactive emulsifier(abbreviated to PURE) was applied in the emulsion copolymerization of methyl methacrylate(MMA) and butyl acrylate(BA). The morphology of the latex particles, water resistance, adhesion capacity, tensile shear strength and thermal stability of the copolymers were investigated. The copolymer latexes obtained in the presence of PURE are consisted of monodispersed latex particles with a diameter of ca. 0.2 μm. Experimental results show that the latex films obtained possess adhesion capacity in grade 1 and tensile shear strength of τ=3.43 MPa, better than that of the common latex film. Their water-absorption rate and water-dissolving rate are only 46.4%and 19.6%, respectively, of those of the common latex films. But the thermal stability of the emulsifier-free latex films is lower than that of the common copolymer film.
