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2004 Volume 21 Issue 4
2004, 21(4): 325-331
Abstract:
Recent advancements on the carbon black (CB) filled electroconductive composites (LCPC) are reviewed in this paper, including six kinds of the CB filled polymers, with emphasis on the mechanism of their gas sensitiveness. The problems present in the exploitation of the LCPC materials and their promising prospects are discussed at last.
Recent advancements on the carbon black (CB) filled electroconductive composites (LCPC) are reviewed in this paper, including six kinds of the CB filled polymers, with emphasis on the mechanism of their gas sensitiveness. The problems present in the exploitation of the LCPC materials and their promising prospects are discussed at last.
2004, 21(4): 332-337
Abstract:
Some methods of preparing chitooligosaccharides, chemical hydrolysis, enzyme hydrolysis, transg-lycosylation and physical degradation are reviewed in this paper, including their technological specilities and variety of products. The recent developments of research at home and abroad are introduced.
Some methods of preparing chitooligosaccharides, chemical hydrolysis, enzyme hydrolysis, transg-lycosylation and physical degradation are reviewed in this paper, including their technological specilities and variety of products. The recent developments of research at home and abroad are introduced.
2004, 21(4): 338-342
Abstract:
A series of amphiphilic diblock copolymers poly (L-leucine acid)-b-poly (ethylene glycol) monomethyl ether of lifterent molecular weights were synthesized by the ring-opening polymerization of L-leucine N-carboxy anhydride (NCA) onto amine-terminated poly(ethylene glycol) monomethyl ether (MPEG-NH2) as a macroinitiator. Their structures and properties were characterized by IR,1H NMR, DSC, GPC and wateruptake measurements. The results showed that the copolymer samples from the ring opening polymerization of NCA had the expected block structures. The block contents and number-average molecular weights of the copolymers, calculated based on the data of 1H NMR spectra, could be adjusted by changing the feeding ratio of NCA to the macroinitiator. Owing to incorporation of the hydrophilic MPEG block, the hydrophilicity of these diblock copolymers was much improved than that of the homopolymer poly(L-leucine).
A series of amphiphilic diblock copolymers poly (L-leucine acid)-b-poly (ethylene glycol) monomethyl ether of lifterent molecular weights were synthesized by the ring-opening polymerization of L-leucine N-carboxy anhydride (NCA) onto amine-terminated poly(ethylene glycol) monomethyl ether (MPEG-NH2) as a macroinitiator. Their structures and properties were characterized by IR,1H NMR, DSC, GPC and wateruptake measurements. The results showed that the copolymer samples from the ring opening polymerization of NCA had the expected block structures. The block contents and number-average molecular weights of the copolymers, calculated based on the data of 1H NMR spectra, could be adjusted by changing the feeding ratio of NCA to the macroinitiator. Owing to incorporation of the hydrophilic MPEG block, the hydrophilicity of these diblock copolymers was much improved than that of the homopolymer poly(L-leucine).
2004, 21(4): 343-347
Abstract:
The dehydrogenation of 1,4-butanediol to γ-butyrolactone over copper-chromite catalysts at atmospheric pressure has been carried out in a fixed-bed reactor.The effects of reaction conditions on the performance of catalyst have been investigated. The results show that for Cu-Cr-Ca-Ba catalyst the conversion of 1, 4-butanediol is ≥99.9% and the yield of γ-butyrolactone is ≥96% under the conditions:LHSV 0.3~0.7 h-1, reaction temperature 180~200℃ and n(H2)/n(BDO) 15~30.The XRD and TG-DTG characterization results show that Cu0 is the active site of the catalyst in dehydrogenation and the presence of Cr is in favor15 of high dispersion of Cu, which results in increasing of the dehydrogenation activity and selectivity. Addition of Ca and Ba as promoters let the reaction temperature reduce to a lower degree and led to an increased yield of γ-butyrolactone.
The dehydrogenation of 1,4-butanediol to γ-butyrolactone over copper-chromite catalysts at atmospheric pressure has been carried out in a fixed-bed reactor.The effects of reaction conditions on the performance of catalyst have been investigated. The results show that for Cu-Cr-Ca-Ba catalyst the conversion of 1, 4-butanediol is ≥99.9% and the yield of γ-butyrolactone is ≥96% under the conditions:LHSV 0.3~0.7 h-1, reaction temperature 180~200℃ and n(H2)/n(BDO) 15~30.The XRD and TG-DTG characterization results show that Cu0 is the active site of the catalyst in dehydrogenation and the presence of Cr is in favor15 of high dispersion of Cu, which results in increasing of the dehydrogenation activity and selectivity. Addition of Ca and Ba as promoters let the reaction temperature reduce to a lower degree and led to an increased yield of γ-butyrolactone.
2004, 21(4): 348-351
Abstract:
Azo dye Orange Ⅱand K2Cr2O7 solution were used as objects to investigate the effect of TiO2 photocatalytic redox ability in the presence of β-cyclodextrin(β-CD) based on the quantification of the rates of dye decolouration and Cr(Ⅵ). The experiment results showed that β-CD was adsorbed on TiO2 surface and the maximal adsorption was obtained when the pH value of the object solution equals(isoelectric point). The oxidation rates of the Orange Ⅱ and deoxidization rates of Cr(Ⅵ) catalyzed by TiO2 mixed with β-CD were 22.3 and 8.0 times, respectively of the neat TiO2 solution related to value of pH of the solution.
Azo dye Orange Ⅱand K2Cr2O7 solution were used as objects to investigate the effect of TiO2 photocatalytic redox ability in the presence of β-cyclodextrin(β-CD) based on the quantification of the rates of dye decolouration and Cr(Ⅵ). The experiment results showed that β-CD was adsorbed on TiO2 surface and the maximal adsorption was obtained when the pH value of the object solution equals(isoelectric point). The oxidation rates of the Orange Ⅱ and deoxidization rates of Cr(Ⅵ) catalyzed by TiO2 mixed with β-CD were 22.3 and 8.0 times, respectively of the neat TiO2 solution related to value of pH of the solution.
2004, 21(4): 352-356
Abstract:
Three polyvinyl acetate(PVAc) complexes with Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) have been synthesized by the reaction of polyvinyl acetate, respectively, with CoCl2, NiCl2 and FeCl3 in THF at room tempre-ture and one hour was appropriate for reaction. The mole ratio of metal ion to[-CH2-CH(OCOCH3)-] segment as found by conductivity measurement was 1:4 in complexes PVAc-Co(Ⅱ) and PVAc-Ni(Ⅱ), but it was 1:3 to 1:6 and more in complex PVAc-Fe(Ⅲ). IR spectra and XPS showed the complex PVAc-Fe(Ⅲ) is formed by non-paired electrons from oxygen atom of CH3COO group in PVAc with metal ions. TG-DTA revealed the heat stability of complexes was higher than that of PVAc. The proposed structures of the complexes were given.
Three polyvinyl acetate(PVAc) complexes with Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) have been synthesized by the reaction of polyvinyl acetate, respectively, with CoCl2, NiCl2 and FeCl3 in THF at room tempre-ture and one hour was appropriate for reaction. The mole ratio of metal ion to[-CH2-CH(OCOCH3)-] segment as found by conductivity measurement was 1:4 in complexes PVAc-Co(Ⅱ) and PVAc-Ni(Ⅱ), but it was 1:3 to 1:6 and more in complex PVAc-Fe(Ⅲ). IR spectra and XPS showed the complex PVAc-Fe(Ⅲ) is formed by non-paired electrons from oxygen atom of CH3COO group in PVAc with metal ions. TG-DTA revealed the heat stability of complexes was higher than that of PVAc. The proposed structures of the complexes were given.
2004, 21(4): 357-360
Abstract:
The porous chitosan microspheres were prepared. Their activation and immobilization with urease were investigated. It is found that the immobilized urease exihibited storage stability better than the free urease, but with lower activity. The chitosan-immobilized uease was applied as a bioreactor in the determination of urea in waste water by flow injection analysis. The linear range of urea concentration was 1.0×10-5~5.0×10-3 g/mL with the mean recovery being (100.5±3.2)%, detection limit was 1.0×10-5g/mL
The porous chitosan microspheres were prepared. Their activation and immobilization with urease were investigated. It is found that the immobilized urease exihibited storage stability better than the free urease, but with lower activity. The chitosan-immobilized uease was applied as a bioreactor in the determination of urea in waste water by flow injection analysis. The linear range of urea concentration was 1.0×10-5~5.0×10-3 g/mL with the mean recovery being (100.5±3.2)%, detection limit was 1.0×10-5g/mL
2004, 21(4): 361-364
Abstract:
Fullerene complex C60Ru(OCOCF3)(CO)(PPh3) was perpared by reduction-substitution reactionof C60 with Ru(OCOCF3)2(CO)(PPh3)2 under nitrogen atmosphere and refluxing, and the complex was characterized by elemental analysis, FT-IR, UV-vis,13CNMR and XPS. The results showed that in complex each moiety of PPh3, -OCOCF3, and CO takes one coordination site from the central metal, and C60 takes the two remaining sites in σ-π back-bonding. The redox experiments of the complex indicated the reduction potential of the complex was more negative than that of the pure C60.
Fullerene complex C60Ru(OCOCF3)(CO)(PPh3) was perpared by reduction-substitution reactionof C60 with Ru(OCOCF3)2(CO)(PPh3)2 under nitrogen atmosphere and refluxing, and the complex was characterized by elemental analysis, FT-IR, UV-vis,13CNMR and XPS. The results showed that in complex each moiety of PPh3, -OCOCF3, and CO takes one coordination site from the central metal, and C60 takes the two remaining sites in σ-π back-bonding. The redox experiments of the complex indicated the reduction potential of the complex was more negative than that of the pure C60.
2004, 21(4): 365-368
Abstract:
The removal of the total particulate matter from cigarette smoke by the filter tips filled with carbon nanotubes(CNTs), active carbon, NaCl, MgSO4 and Al(OH)3 has been compared. The results show that the removal efficiency of light purified CNTs(immersed in nitric acid for 5 minutes) is higher than that of other materials, even higher than that of heavy purified CNTs(boiled in nitric acid for 40 minutes). The optimal mass of the light purified CNTs for one cigarette is 20~30 mg.
The removal of the total particulate matter from cigarette smoke by the filter tips filled with carbon nanotubes(CNTs), active carbon, NaCl, MgSO4 and Al(OH)3 has been compared. The results show that the removal efficiency of light purified CNTs(immersed in nitric acid for 5 minutes) is higher than that of other materials, even higher than that of heavy purified CNTs(boiled in nitric acid for 40 minutes). The optimal mass of the light purified CNTs for one cigarette is 20~30 mg.
2004, 21(4): 369-373
Abstract:
Three binuclear Mn(Ⅲ) complexes[Mn2(DSH) (acac)2(EtOH)2]·2H2O(1),[Mn2(DSH)-(acac)2(H2O)2]·2H2O(2) and[Mn2(DSH)(acac)2(py)2] (3), where DSH(1, 2-disalicyloyl-hydrazine) is the ligand, have been synthesized and characterized by X-ray diffractometry and cyclic voltammetry. Complex 1 crystallizes in triclinic, space group P1, a=1.197 60(6)nm, b=1.208 04(7) nm, c=1.372 98(7) nm, α=89..737(2)°, β=65.900(4)°, γ=68.752(2)°and Z=2. Complex 2 crystallizes in monoclinic, space group P21/n,a=1.196 5(1)nm, b=0.823 17(7)nm, c=1.400 1(1)nm, β=101.035(4)°and Z=2. Complex 3 also crystallizes in monoclinic, space group P21/n, a=1.183 11(5)nm, b=0.886 93(5)nm, c=1.655 37(8)nm, β=100.581(4)°and Z=2. In all of the three title complexes, there are centrosymmetrical binuclear manganese complex molecules. Each ligand DSH4- in these complexes bridges the two Mn atoms through its hydrazine N-N group. The manganese atoms in the three complexes have a distorted octahedral geometry.
Three binuclear Mn(Ⅲ) complexes[Mn2(DSH) (acac)2(EtOH)2]·2H2O(1),[Mn2(DSH)-(acac)2(H2O)2]·2H2O(2) and[Mn2(DSH)(acac)2(py)2] (3), where DSH(1, 2-disalicyloyl-hydrazine) is the ligand, have been synthesized and characterized by X-ray diffractometry and cyclic voltammetry. Complex 1 crystallizes in triclinic, space group P1, a=1.197 60(6)nm, b=1.208 04(7) nm, c=1.372 98(7) nm, α=89..737(2)°, β=65.900(4)°, γ=68.752(2)°and Z=2. Complex 2 crystallizes in monoclinic, space group P21/n,a=1.196 5(1)nm, b=0.823 17(7)nm, c=1.400 1(1)nm, β=101.035(4)°and Z=2. Complex 3 also crystallizes in monoclinic, space group P21/n, a=1.183 11(5)nm, b=0.886 93(5)nm, c=1.655 37(8)nm, β=100.581(4)°and Z=2. In all of the three title complexes, there are centrosymmetrical binuclear manganese complex molecules. Each ligand DSH4- in these complexes bridges the two Mn atoms through its hydrazine N-N group. The manganese atoms in the three complexes have a distorted octahedral geometry.
2004, 21(4): 374-377
Abstract:
A novel fluorescence reagent bis(benzotriazo-1-le)-ethyldione semicarbazone(BTES)was synthesized from 1-H-benzotriazole, biformyl and semicarbazide. The structure of the reagent was characterized by elemental analysis, IR spectrometry and 1H NMR spectrometry. The reagent gave fluorescence emission at 342 nm in a KH2PO4-H3PO4 buffer solution(pH=4.0). A new method for the determination of trace protein has been developed based on the enhanced fluorescence emission in the presence of a certain amount of protein. Under optimal conditions the linear range concentration was at 08.0×10-6g/mL and 1.0×10-50.25g/mL, for bovine serum albumen and human serum albumen, respectively. The detection limit was 5.3×10-9g/mL and 1.4×10-9g/mL, respectively. The method has been tested on the synthesized samples with satisfactory results.
A novel fluorescence reagent bis(benzotriazo-1-le)-ethyldione semicarbazone(BTES)was synthesized from 1-H-benzotriazole, biformyl and semicarbazide. The structure of the reagent was characterized by elemental analysis, IR spectrometry and 1H NMR spectrometry. The reagent gave fluorescence emission at 342 nm in a KH2PO4-H3PO4 buffer solution(pH=4.0). A new method for the determination of trace protein has been developed based on the enhanced fluorescence emission in the presence of a certain amount of protein. Under optimal conditions the linear range concentration was at 08.0×10-6g/mL and 1.0×10-50.25g/mL, for bovine serum albumen and human serum albumen, respectively. The detection limit was 5.3×10-9g/mL and 1.4×10-9g/mL, respectively. The method has been tested on the synthesized samples with satisfactory results.
2004, 21(4): 378-382
Abstract:
The high active Ti/nano-TiO2-Pt electrode is prepared by electrochemical synthesis and electrodeposition. The electrochemical behavior of the TiO2/nano membrane electrode, Pt electrode and Ti/nano-TiO2-Pt electrode in H2SO4 solution have been studied by cyclic voltammetry. The property of Ti/nano-TiO2-Pt electrode in oxidation of Mn2+ to Mn3+ is also studied. The results show that the Ti/nano-Pt electrode has high catalytic activity in Mn2+ oxidation of 1.28 V(vs. SCE) oxidation potential peak, 0.12 V negative shifted as compared with that occurrs on Pt electrode. The oxygen-releasing potential is 1.4 V, about 0.08 V higher than that of Pt electrode. The electro-catalysis property of Ti/nano-TiO2-Pt electrode is better than that of the Pt electrode and Ti/nano electrode, it gives a average current efficiency more than 90% in non-homogeneous electrolytical oxidation of Mn2+ to Mn3+.
The high active Ti/nano-TiO2-Pt electrode is prepared by electrochemical synthesis and electrodeposition. The electrochemical behavior of the TiO2/nano membrane electrode, Pt electrode and Ti/nano-TiO2-Pt electrode in H2SO4 solution have been studied by cyclic voltammetry. The property of Ti/nano-TiO2-Pt electrode in oxidation of Mn2+ to Mn3+ is also studied. The results show that the Ti/nano-Pt electrode has high catalytic activity in Mn2+ oxidation of 1.28 V(vs. SCE) oxidation potential peak, 0.12 V negative shifted as compared with that occurrs on Pt electrode. The oxygen-releasing potential is 1.4 V, about 0.08 V higher than that of Pt electrode. The electro-catalysis property of Ti/nano-TiO2-Pt electrode is better than that of the Pt electrode and Ti/nano electrode, it gives a average current efficiency more than 90% in non-homogeneous electrolytical oxidation of Mn2+ to Mn3+.
2004, 21(4): 383-387
Abstract:
The charge transfer compound[CH3NH2CH3]2[CH3 NHCH3]4H4[P2W18O62]·H2O with polyoxometalate subunit has been synthesized from octadecatungstodiphosphoric acid and dimethylamine in acetonitrile aqueous solution, and characterized by IR, UV spectral techniques. X-ray single crystal structural analysis indicates the title compound crystallizes in the monoclinic space group P21/n, with lattice parameters a=2.306 2(5) nm, b=1.383 1(3) nm, c=2.468 8(5) nm, β=113.95(3)°, V=7.197(2)nm3, Z=4, R1=0.052 3. The title compound consists of two protonated dimethylamine molecules, four dimethylamine molecules, one water molecule, four protons and a heteropolyanion of [P2W18O62]6-. The results of IR spectra and X-ray single crystal diffraction reveal that there is comparatively stronger interaction between organic groups and heteropolyanions in the solid state. The curve of TG-DTA elucidates that the process of mass loss of the title compound is carried out in three stages. The study of temperature-changing IR spectra reveals that the framework of the heteropolyanion decomposes at ca. 500℃.
The charge transfer compound[CH3NH2CH3]2[CH3 NHCH3]4H4[P2W18O62]·H2O with polyoxometalate subunit has been synthesized from octadecatungstodiphosphoric acid and dimethylamine in acetonitrile aqueous solution, and characterized by IR, UV spectral techniques. X-ray single crystal structural analysis indicates the title compound crystallizes in the monoclinic space group P21/n, with lattice parameters a=2.306 2(5) nm, b=1.383 1(3) nm, c=2.468 8(5) nm, β=113.95(3)°, V=7.197(2)nm3, Z=4, R1=0.052 3. The title compound consists of two protonated dimethylamine molecules, four dimethylamine molecules, one water molecule, four protons and a heteropolyanion of [P2W18O62]6-. The results of IR spectra and X-ray single crystal diffraction reveal that there is comparatively stronger interaction between organic groups and heteropolyanions in the solid state. The curve of TG-DTA elucidates that the process of mass loss of the title compound is carried out in three stages. The study of temperature-changing IR spectra reveals that the framework of the heteropolyanion decomposes at ca. 500℃.
2004, 21(4): 388-391
Abstract:
A superabsorbent polymer good resistant to saline solution was prepared by solution polymerization of acrylic acid(AA) using alumina as a crosslinking agent. The influences of amount of crosslinking agent, initiator, neutralization degree of acrylic acid, molar ratio of NH3 to(NH3+NaOH), polymerization time, temperature on water absorbency(WA) in 0.9% NaCl aqueous solution were investigated. The optimum reaction conditions were 0.34% molar fraction of crosslinking agent, 0.0013% molar fraction of initiator, 77% neutralization degree, polymerization at 50℃ and 6h. Water absorbency in distilled water and in aqueous 0.9% NaCl solution in 30 min was about 2 225g/g and 100g/g, respectively.
A superabsorbent polymer good resistant to saline solution was prepared by solution polymerization of acrylic acid(AA) using alumina as a crosslinking agent. The influences of amount of crosslinking agent, initiator, neutralization degree of acrylic acid, molar ratio of NH3 to(NH3+NaOH), polymerization time, temperature on water absorbency(WA) in 0.9% NaCl aqueous solution were investigated. The optimum reaction conditions were 0.34% molar fraction of crosslinking agent, 0.0013% molar fraction of initiator, 77% neutralization degree, polymerization at 50℃ and 6h. Water absorbency in distilled water and in aqueous 0.9% NaCl solution in 30 min was about 2 225g/g and 100g/g, respectively.
2004, 21(4): 392-395
Abstract:
The dispersion effect of acrylate copolymer binder consisted of butyl acrylace(BA) and acrylic acid (AA) on red pigment cake PR48:2 was studied. The results showed that the best dispersion could be obtained as the stirring time over 3 h, ω(AA)=40% and ω(BPO)=2%, the red value in colour three stimuli characterisation of the dispersion film was 66, higher than that from pigment powder(44). The dispersion of pigment press cake showed higher colour strength, and the pigment kept better colour characteristic.
The dispersion effect of acrylate copolymer binder consisted of butyl acrylace(BA) and acrylic acid (AA) on red pigment cake PR48:2 was studied. The results showed that the best dispersion could be obtained as the stirring time over 3 h, ω(AA)=40% and ω(BPO)=2%, the red value in colour three stimuli characterisation of the dispersion film was 66, higher than that from pigment powder(44). The dispersion of pigment press cake showed higher colour strength, and the pigment kept better colour characteristic.
2004, 21(4): 396-399
Abstract:
The coagulant polyferrous sulfate silicate(PFSS) was prepared from ferrous sulfate and sodium silicate. The influences of the mole ratio of SiO2 to Fe, the mass concentration of PFSS, and the pH and temperature of water on coagulation performance of PFSS have been investigated. The sedimentation process of PFSS was researched by an on-line operation system of spectrophotometer combined with function recording instrument. The results show that the coagulation performance of PFSS was strengthened with the increase of the mole ratio of SiO2 to Fe and the temperature of water. PFSS can be used in a wider pH range, and its flocculation and sedimentation performance are better than that of ferrous sulfate. When the mole ratio of SiO2 to Fe was changed from 1:1 tO2:1, the turbidity of water is 20.5NTU mass concentration of PFSS being 0.75 mg/L. The turbity of treated was decreased to less 2NTU at pH>7.
The coagulant polyferrous sulfate silicate(PFSS) was prepared from ferrous sulfate and sodium silicate. The influences of the mole ratio of SiO2 to Fe, the mass concentration of PFSS, and the pH and temperature of water on coagulation performance of PFSS have been investigated. The sedimentation process of PFSS was researched by an on-line operation system of spectrophotometer combined with function recording instrument. The results show that the coagulation performance of PFSS was strengthened with the increase of the mole ratio of SiO2 to Fe and the temperature of water. PFSS can be used in a wider pH range, and its flocculation and sedimentation performance are better than that of ferrous sulfate. When the mole ratio of SiO2 to Fe was changed from 1:1 tO2:1, the turbidity of water is 20.5NTU mass concentration of PFSS being 0.75 mg/L. The turbity of treated was decreased to less 2NTU at pH>7.
2004, 21(4): 400-404
Abstract:
Ammonium nitrate(AN) is modified by chemical fertilizer such as diammonium phosphate, monoammonium phosphate, ammonium sulfate, potassium sulfate and ammonium chloride, and then mixed with fuel oil and sawdust to make ANFO explosives. The explosives were initiated by No.8 detonator. The thermal decomposition of the modified AN and ANFO explosives have been studied by isothermal and differential scanning calorimetry(DSC) in sealed capillary and anti-pressure sealed cell, respectively. It is found that the detonation of ANFO explosives can not be initiated with more than 40% monoammonium phosphate, 20% diammonium phosphate, 25% ammonium sulfate or 25% potassium sulfate in the modified AN. Detonation results are consistent with isothermal data, namely all the undetonated explosives possess the feature of decomposition percent less than 50% on heating at 370℃ for 1 minute. Chloride ion catalyzes the decomposition of AN, so the modified AN could be detonated with 30% ammonium chloride and decomposition percent is nearly 100% on heating at 370℃ for 1 minute.
Ammonium nitrate(AN) is modified by chemical fertilizer such as diammonium phosphate, monoammonium phosphate, ammonium sulfate, potassium sulfate and ammonium chloride, and then mixed with fuel oil and sawdust to make ANFO explosives. The explosives were initiated by No.8 detonator. The thermal decomposition of the modified AN and ANFO explosives have been studied by isothermal and differential scanning calorimetry(DSC) in sealed capillary and anti-pressure sealed cell, respectively. It is found that the detonation of ANFO explosives can not be initiated with more than 40% monoammonium phosphate, 20% diammonium phosphate, 25% ammonium sulfate or 25% potassium sulfate in the modified AN. Detonation results are consistent with isothermal data, namely all the undetonated explosives possess the feature of decomposition percent less than 50% on heating at 370℃ for 1 minute. Chloride ion catalyzes the decomposition of AN, so the modified AN could be detonated with 30% ammonium chloride and decomposition percent is nearly 100% on heating at 370℃ for 1 minute.
2004, 21(4): 405-409
Abstract:
A series of hydrophobically associating twin-tailed water-soluble terpolymers poly(acrylamide/sodium acrylate/dihexylacrylamide)[P(AM/NaAA/DiC6AM)] were synthesized by radical micellar copolymerization. Their apparent viscosities were found to be increased and their critical associating concentrations decreased dramatically in the presence of sodium dodecyl sulfate (SDS). The effects of the surfactant to hydrophobic monomer molar ratio[n(SDS)/n (hydrophobic monomer)], the hydrophobic momomer content, temperature and shear rate on aqueous solution viscosity of the unpurified terpolymers have been investigated. The apparent viscosities of the unpurified terpolymers were decreased with the increase in n(SDS)/n(hydrophobic monomer), temperature and shear rate; but increased firstly and then decreased with increase in the hydrophobic momomer content. The terpolymers showed a superior dissolution property when the hydrophobic momomer contents are from 0.125% to 0.375%, n(SDS)/n(hydrophobic monomer)are from 10% to 20%.
A series of hydrophobically associating twin-tailed water-soluble terpolymers poly(acrylamide/sodium acrylate/dihexylacrylamide)[P(AM/NaAA/DiC6AM)] were synthesized by radical micellar copolymerization. Their apparent viscosities were found to be increased and their critical associating concentrations decreased dramatically in the presence of sodium dodecyl sulfate (SDS). The effects of the surfactant to hydrophobic monomer molar ratio[n(SDS)/n (hydrophobic monomer)], the hydrophobic momomer content, temperature and shear rate on aqueous solution viscosity of the unpurified terpolymers have been investigated. The apparent viscosities of the unpurified terpolymers were decreased with the increase in n(SDS)/n(hydrophobic monomer), temperature and shear rate; but increased firstly and then decreased with increase in the hydrophobic momomer content. The terpolymers showed a superior dissolution property when the hydrophobic momomer contents are from 0.125% to 0.375%, n(SDS)/n(hydrophobic monomer)are from 10% to 20%.
2004, 21(4): 410-414
Abstract:
Lithium vanadium oxide LiV3O8 was synthesized by a sol-gel method followed by calcination. The V2O5·nH2O hydro-gel was prepared by reacting V2O5 with 10% H2O2, and aged for 4 days at room temperature. The LiV3O8 precursor was obtained from V2O5·nH2O hydro-gel and Li2CO3 and dried at 120℃, and the LiV3O8 was obtained after calcination at 400℃ for 20h. Compared with the conventional high temperature solid phase reaction methods, this method has the advantages of the lower synthesis temperature and smaller particle size of the product. The precursor and product were characterized by DTA-TG, XRD and ICP measurements. Electrochemical behavior of the LiV3O8 as a cathode material for rechargeable lithium-ion battery was studied by galvanostatic charge-discharge, cyclic voltammetry, and A. C. impedance techniques. The chemical diffusion coefficient(DLi) of lithium was calculated by semi-infinite diffusion impedance model the range of 1×10-8~1×10-11cm2/s. The results showed that the active material LiV3O8 has a specific discharge capacity of 225 mA·h/g at 0.1C rate and voltage limits of 1.8~3.6 V during 20 cycles.
Lithium vanadium oxide LiV3O8 was synthesized by a sol-gel method followed by calcination. The V2O5·nH2O hydro-gel was prepared by reacting V2O5 with 10% H2O2, and aged for 4 days at room temperature. The LiV3O8 precursor was obtained from V2O5·nH2O hydro-gel and Li2CO3 and dried at 120℃, and the LiV3O8 was obtained after calcination at 400℃ for 20h. Compared with the conventional high temperature solid phase reaction methods, this method has the advantages of the lower synthesis temperature and smaller particle size of the product. The precursor and product were characterized by DTA-TG, XRD and ICP measurements. Electrochemical behavior of the LiV3O8 as a cathode material for rechargeable lithium-ion battery was studied by galvanostatic charge-discharge, cyclic voltammetry, and A. C. impedance techniques. The chemical diffusion coefficient(DLi) of lithium was calculated by semi-infinite diffusion impedance model the range of 1×10
2004, 21(4): 415-418
Abstract:
Monomer N,N'-diphenyl-N,N'-bis(4-alkylphenyl)-benzidine(alkyl-TPD) prepared by Ullmann reaction of N,N'-diphenylbenzidine with 1-halogen-4-alkylbenzene using 18-crown-6 as phase transfer catalyst and o-dichlorobenzene as solvent was reacted with 1, 4-bischloromethylbenzene(BCB) or 9, 10-bischloromethylanthracene(BCA) by condensation polymerization through Friedel-Crafts reaction in chlorobenzene, using SnCl4 or AlCl3 as catalysts under nitrogen atmosphere at 40~80℃ for 112h. TPD units were introduced into the main chain of the polymer. A series of the novel EL polymer with charge transporting property were synthesized in high yield(up to 96%) and with high molecular weight(with maximum value 2.9×105). All polymers had higher Tg than that of TPD itself(maximum value of Tg was 245℃). Their properties in electroluminesent devices have been investigated. The results showed EL wavelength is moved 60 nm toward infrared region as compared with that of TPD.
Monomer N,N'-diphenyl-N,N'-bis(4-alkylphenyl)-benzidine(alkyl-TPD) prepared by Ullmann reaction of N,N'-diphenylbenzidine with 1-halogen-4-alkylbenzene using 18-crown-6 as phase transfer catalyst and o-dichlorobenzene as solvent was reacted with 1, 4-bischloromethylbenzene(BCB) or 9, 10-bischloromethylanthracene(BCA) by condensation polymerization through Friedel-Crafts reaction in chlorobenzene, using SnCl4 or AlCl3 as catalysts under nitrogen atmosphere at 40~80℃ for 112h. TPD units were introduced into the main chain of the polymer. A series of the novel EL polymer with charge transporting property were synthesized in high yield(up to 96%) and with high molecular weight(with maximum value 2.9×105). All polymers had higher Tg than that of TPD itself(maximum value of Tg was 245℃). Their properties in electroluminesent devices have been investigated. The results showed EL wavelength is moved 60 nm toward infrared region as compared with that of TPD.
2004, 21(4): 419-421
Abstract:
The behavior of N, N, N', N'-tetrabutylmalonamide(TBMA) in extraction of Tin(Ⅲ) using toluene as diluent has been investigated. The effects of the concentrations of TBMA, nitric acid, lithium nitrate, and temperature on the extraction have been studied. The composition of the extracted species was found to be Tm(NO3)3·3TBMA as characterized by IR spectrometry. The apparent equilibrium constant of extraction has been determined to be(0.61±0.18) L6/mol-6 at 298 K. Enthalpy of the extraction reaction is-27.61 kJ/mol.
The behavior of N, N, N', N'-tetrabutylmalonamide(TBMA) in extraction of Tin(Ⅲ) using toluene as diluent has been investigated. The effects of the concentrations of TBMA, nitric acid, lithium nitrate, and temperature on the extraction have been studied. The composition of the extracted species was found to be Tm(NO3)3·3TBMA as characterized by IR spectrometry. The apparent equilibrium constant of extraction has been determined to be(0.61±0.18) L6/mol-6 at 298 K. Enthalpy of the extraction reaction is-27.61 kJ/mol.
2004, 21(4): 422-424
Abstract:
The binding reaction of cytidine 5'-phosphate(5'-CMP) with Alizarin Red S(ARS) was studied in the buffer solution(pH=4.56) as functions of temperature, time, ionic strength and interference of inorganic substance, biological substance and surfactant by UV-Vis spectrophotometry. It was found that the bathochromic shift of the maximum absorption peak of the complex was 90nm. The apparemt molar absorptivity was ε=3.80×103 L/(mol·cm), the binding number was n=13, and the linear range of reaction was 0~14 mg/L.
The binding reaction of cytidine 5'-phosphate(5'-CMP) with Alizarin Red S(ARS) was studied in the buffer solution(pH=4.56) as functions of temperature, time, ionic strength and interference of inorganic substance, biological substance and surfactant by UV-Vis spectrophotometry. It was found that the bathochromic shift of the maximum absorption peak of the complex was 90nm. The apparemt molar absorptivity was ε=3.80×103 L/(mol·cm), the binding number was n=13, and the linear range of reaction was 0~14 mg/L.
2004, 21(4): 425-427
Abstract:
The effects of light wave on the stability of ferrate solution have been examined. The results showed that UV-light accelerates the decomposition of ferrate with decomposition rate 1.6 times as much as that in dark whereas infrared light has only unclear effect on the stability of ferrate, with decomposition rate 1.1 times as much as in dark. The polythene container is found to the best for preservation of ferrate solution in dark.
The effects of light wave on the stability of ferrate solution have been examined. The results showed that UV-light accelerates the decomposition of ferrate with decomposition rate 1.6 times as much as that in dark whereas infrared light has only unclear effect on the stability of ferrate, with decomposition rate 1.1 times as much as in dark. The polythene container is found to the best for preservation of ferrate solution in dark.
2004, 21(4): 428-429
Abstract:
Six 4-aryl-5-methoxylcarbonyl-6-methyl-3, 4-dihydropyrid-2-ones have been synthesized by the reaction of aromatic aldehyde, methyl acetoactate, meldrum's acid and ammonium acetate under microwave irradiation without solvent. The method has advantages of rapidity, mild condition, without solvent and higher yield.
Six 4-aryl-5-methoxylcarbonyl-6-methyl-3, 4-dihydropyrid-2-ones have been synthesized by the reaction of aromatic aldehyde, methyl acetoactate, meldrum's acid and ammonium acetate under microwave irradiation without solvent. The method has advantages of rapidity, mild condition, without solvent and higher yield.
2004, 21(4): 430-432
Abstract:
The interaction sites between microperoxidase-8(MP-8) and Eu3+ was determined using electrochemical techniques. It is found that two Eu3+ ions would coordinate strongly with carboxylate oxygen of two propionic acid groups of the heme group in an MP-8 molecule, leading to the increase in the reversibility of the electrochemical reaction of MP-8. The excessive Eu3+ ions weakly interact with the oxygen containing groups in the peptide chain of MP-8.
The interaction sites between microperoxidase-8(MP-8) and Eu3+ was determined using electrochemical techniques. It is found that two Eu3+ ions would coordinate strongly with carboxylate oxygen of two propionic acid groups of the heme group in an MP-8 molecule, leading to the increase in the reversibility of the electrochemical reaction of MP-8. The excessive Eu3+ ions weakly interact with the oxygen containing groups in the peptide chain of MP-8.
