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2001 Volume 18 Issue 9
2001, 18(9): 682-684
Abstract:
The effects of calcium ion and rare earth ions on the activity of a phospholipase A2(PL2) obtained from Chinese Agkistrodon blomhoffii Ussurensis venom have been investigated.The results indicated that the activity of snake venom PLA2 is dependent on the concentration of calcium ion.Calmodulin(CAM), a calcium dependent regulator can also stimulate the activity of PLA2.La3+,Eu3+,Dy3+,Yb3+ showed different levels of inhibitory effects on the PLA2's activity mostly due to difference in ion radius.The relative activity of PLA2 inhibited by La3+ or Yb3+ at the concentration of 13.5μmol/L was 63.5% and 31.8%, respectively.
The effects of calcium ion and rare earth ions on the activity of a phospholipase A2(PL2) obtained from Chinese Agkistrodon blomhoffii Ussurensis venom have been investigated.The results indicated that the activity of snake venom PLA2 is dependent on the concentration of calcium ion.Calmodulin(CAM), a calcium dependent regulator can also stimulate the activity of PLA2.La3+,Eu3+,Dy3+,Yb3+ showed different levels of inhibitory effects on the PLA2's activity mostly due to difference in ion radius.The relative activity of PLA2 inhibited by La3+ or Yb3+ at the concentration of 13.5μmol/L was 63.5% and 31.8%, respectively.
2001, 18(9): 685-688
Abstract:
Nine azobis(2 pyridine) containing metal complexes:Mn2(APY)-(Mebix)2(Ac)4·4H2O(1);Cu2(APY)(Mebix)2(Ac)4·4H2O(2); Ni2(APY)(Mebix)2(Ac)4·4H2O(3); Cu2(APY)-(bix)2(Ac)4·6H2O(4); Ni2(APY)(bix)2(Ac)4·6H2O(5); Mn2(APY)-(bix)2(Ac)4·4H2O(6); CuGd-(APY)(bix)2(Ac)2(NO3)3·6H2O(7); NiGd(APY)(bix)2(Ac)2(NO3) 3·6H2O(8); MnGd(APY)-(bix)2(Ac)2(NO3)3·6H2O(9) have been prepared and characterized by elemental analysis, infrared, electronic spectra, and ESR.The molecular mechanics and quantum chemical studies have also been engaged to interpret their properties.The cyclic voltammogram studies show that the oxidation reduction processes of (1)~(6) appear to involve an oxidation reduction of APY and two step two electron transfer processes of the bimetallic cores; while the oxidation reduction processes of (7)~(9) involve an oxidation reduction of APY and one step two electron transfer processes of 3d metallic cores.The molecular mechanics and quantum chemical studies demonstrate that there would be a weak antiferromagnetic interaction between the two copper(Ⅱ) units in complex (1), which agrees with the result evaluated by ESR (-2J=11.6 cm-1).
Nine azobis(2 pyridine) containing metal complexes:Mn2(APY)-(Mebix)2(Ac)4·4H2O(1);Cu2(APY)(Mebix)2(Ac)4·4H2O(2); Ni2(APY)(Mebix)2(Ac)4·4H2O(3); Cu2(APY)-(bix)2(Ac)4·6H2O(4); Ni2(APY)(bix)2(Ac)4·6H2O(5); Mn2(APY)-(bix)2(Ac)4·4H2O(6); CuGd-(APY)(bix)2(Ac)2(NO3)3·6H2O(7); NiGd(APY)(bix)2(Ac)2(NO3) 3·6H2O(8); MnGd(APY)-(bix)2(Ac)2(NO3)3·6H2O(9) have been prepared and characterized by elemental analysis, infrared, electronic spectra, and ESR.The molecular mechanics and quantum chemical studies have also been engaged to interpret their properties.The cyclic voltammogram studies show that the oxidation reduction processes of (1)~(6) appear to involve an oxidation reduction of APY and two step two electron transfer processes of the bimetallic cores; while the oxidation reduction processes of (7)~(9) involve an oxidation reduction of APY and one step two electron transfer processes of 3d metallic cores.The molecular mechanics and quantum chemical studies demonstrate that there would be a weak antiferromagnetic interaction between the two copper(Ⅱ) units in complex (1), which agrees with the result evaluated by ESR (-2J=11.6 cm-1).
2001, 18(9): 689-692
Abstract:
Y-doped α-Ni(OH)2 has been synthesized by partially substitution of nickel hydroxide with Y.The structure, morphology and composition of the compound have been investigated by X-ray diffraction.Fourier transform infrared spectroscopy and scanning electron microscopy.The prepared Y doped α-Ni(OH)2 has larger packed density(1.6 g/mL), greater specific capacity(>330 mA·h/g) and higher utilization ratio(>95%) of active material than the aluminum doped α-Ni(OH)2 and U-Ni(OH)2.Cyclic voltammetry suggests that the compound has better reversibility.
Y-doped α-Ni(OH)2 has been synthesized by partially substitution of nickel hydroxide with Y.The structure, morphology and composition of the compound have been investigated by X-ray diffraction.Fourier transform infrared spectroscopy and scanning electron microscopy.The prepared Y doped α-Ni(OH)2 has larger packed density(1.6 g/mL), greater specific capacity(>330 mA·h/g) and higher utilization ratio(>95%) of active material than the aluminum doped α-Ni(OH)2 and U-Ni(OH)2.Cyclic voltammetry suggests that the compound has better reversibility.
2001, 18(9): 693-696
Abstract:
The effects of addition of Mg to CaCO3 supported Cu-Ni catalyst in catalytic amination of dodecyl alcohol with dimethylamine have been investigated.It is found that Mg can effectively promote the selectivity of the catalyst due to its prohibition effect on the reduction of Ni.The XPS results of the catalysts revealed that Ni in the catalyst with added Mg has a relatively higher positive charge.The higher the positive charge of Ni, the higher the selectivity of the catalysts.
The effects of addition of Mg to CaCO3 supported Cu-Ni catalyst in catalytic amination of dodecyl alcohol with dimethylamine have been investigated.It is found that Mg can effectively promote the selectivity of the catalyst due to its prohibition effect on the reduction of Ni.The XPS results of the catalysts revealed that Ni in the catalyst with added Mg has a relatively higher positive charge.The higher the positive charge of Ni, the higher the selectivity of the catalysts.
2001, 18(9): 697-700
Abstract:
The interfacial properties of primary amine N1923 in different diluents 0.1 mol/L (H,Na)NO3 (pH=2.34) liquid/liquid systems have been studied.The interfacial parameters, cmin and AI, of N1923 have been obtained.It was suggested that the monomeric N1923 molecule was the active species adsorbed at the interface.The interfacial activity of N1923 in different systems decreased as follows: n-heptane, cyclohexane, benzene, toluene, carbon tetrachloride, chloroform, isoamyl acetate and methyliso-butylketone(MIBK).This results were possibly due to the interaction between diluents and extractant, extractant and water molecules near interfacial layer, and diluents and water molecules near interfacial layer.The relationship between the interfacial properties and extraction reaction have also been discussed.
The interfacial properties of primary amine N1923 in different diluents 0.1 mol/L (H,Na)NO3 (pH=2.34) liquid/liquid systems have been studied.The interfacial parameters, cmin and AI, of N1923 have been obtained.It was suggested that the monomeric N1923 molecule was the active species adsorbed at the interface.The interfacial activity of N1923 in different systems decreased as follows: n-heptane, cyclohexane, benzene, toluene, carbon tetrachloride, chloroform, isoamyl acetate and methyliso-butylketone(MIBK).This results were possibly due to the interaction between diluents and extractant, extractant and water molecules near interfacial layer, and diluents and water molecules near interfacial layer.The relationship between the interfacial properties and extraction reaction have also been discussed.
2001, 18(9): 701-704
Abstract:
The effects of the penetration and impregnation reduction preparation methods on the morphology and composition of Pt/SPE electrode were studied by means of SEM, EDS and electrochemical methods.The electrochemical oxidation properties of benzyl alcohol on the prepared Pt/SPE electrodes were investigated.The results showed that by using the impregnation reduction method, the loading and particle sizes of Pt on SPE membrane were reduced, thus the real surface area of Pt/SPE electrode and the specific activity energy could be increased and improved.
The effects of the penetration and impregnation reduction preparation methods on the morphology and composition of Pt/SPE electrode were studied by means of SEM, EDS and electrochemical methods.The electrochemical oxidation properties of benzyl alcohol on the prepared Pt/SPE electrodes were investigated.The results showed that by using the impregnation reduction method, the loading and particle sizes of Pt on SPE membrane were reduced, thus the real surface area of Pt/SPE electrode and the specific activity energy could be increased and improved.
2001, 18(9): 705-708
Abstract:
A gold electrode modified by hepatitis B surface antibody covalently bound to selfassembled thiourea monolayer has been fabricated to detect the hepatitis B surface antigen.The selfassembled monolayer was formed by spontaneous adsorption of thiourea on gold surface and used as a substrate to be modified by anti-hepatitis B surface antigen through glutaraldehyde amide reactions.The modification procedure was electrochemically monitored by characterization of the electrode surface.The immunoelectrode and saturated calomel electrode were dipped together into the serum samples diluted by PBS buffer solution (pH=7.4) for the potentiometric determination.More than 87.5% of the results of the human serum samples obtained by this method were in agreement with those obtained by enzyme linked immunosorbent assay(ELISA).Calibration graphs were linear for HBsAg in range of 6~320 μg/L with correlation coefficient of 0 998 and detection limit of 4 μg/L.The immunoelectrode prepared has good stability and high sensitivity.
A gold electrode modified by hepatitis B surface antibody covalently bound to selfassembled thiourea monolayer has been fabricated to detect the hepatitis B surface antigen.The selfassembled monolayer was formed by spontaneous adsorption of thiourea on gold surface and used as a substrate to be modified by anti-hepatitis B surface antigen through glutaraldehyde amide reactions.The modification procedure was electrochemically monitored by characterization of the electrode surface.The immunoelectrode and saturated calomel electrode were dipped together into the serum samples diluted by PBS buffer solution (pH=7.4) for the potentiometric determination.More than 87.5% of the results of the human serum samples obtained by this method were in agreement with those obtained by enzyme linked immunosorbent assay(ELISA).Calibration graphs were linear for HBsAg in range of 6~320 μg/L with correlation coefficient of 0 998 and detection limit of 4 μg/L.The immunoelectrode prepared has good stability and high sensitivity.
2001, 18(9): 709-712
Abstract:
The strong fluorescence and high thermal stability of sodium tris(pyridine dicarboxylato)europate(Ⅲ), Na3Eu(DPA)3, were used for modification of polycarbonate(PC) resin.The polycarbonate resin composite was prepared at 220℃ for 30 min under stirring.The excitation and emission spectra and thermogravimetric analysis results showed that the prepared Na3Eu(DPA)3-PC composite material retained the fluorescence characteristics and strong red emission of the Eu3+chelate and its fluorescence intensity was found to be increased with increase in the mass fraction of Na3Eu-(DPA)3 in PC resin, but did not in linear relation.
The strong fluorescence and high thermal stability of sodium tris(pyridine dicarboxylato)europate(Ⅲ), Na3Eu(DPA)3, were used for modification of polycarbonate(PC) resin.The polycarbonate resin composite was prepared at 220℃ for 30 min under stirring.The excitation and emission spectra and thermogravimetric analysis results showed that the prepared Na3Eu(DPA)3-PC composite material retained the fluorescence characteristics and strong red emission of the Eu3+chelate and its fluorescence intensity was found to be increased with increase in the mass fraction of Na3Eu-(DPA)3 in PC resin, but did not in linear relation.
2001, 18(9): 713-716
Abstract:
meso-Tetrakis(p-methoxyl)phenylporphyrin(T(p-OCH3)PP) and its Zn-complex (Zn-T(p-OCH3)PP) were synthesized and characterized by elemental analysis,1H NMR, UV and fluorescence spectra.The electrochemical properties of the complex have been investigated by cyclic voltammetry, electrocapillary method in DMSO and a tentative mechanism of reduction on the mercury electrode has been proposed.It is found that the peak currents of the complex are an irreversible adsorption wave.The adsorbed amount of T(p-OCH3)PP and Zn T(p-OCH3)PP on mercury electrode surface were 1.41×10-10 and 6.77×10-11 mol/cm2, respectively as determined by chronoculometry.
meso-Tetrakis(p-methoxyl)phenylporphyrin(T(p-OCH3)PP) and its Zn-complex (Zn-T(p-OCH3)PP) were synthesized and characterized by elemental analysis,1H NMR, UV and fluorescence spectra.The electrochemical properties of the complex have been investigated by cyclic voltammetry, electrocapillary method in DMSO and a tentative mechanism of reduction on the mercury electrode has been proposed.It is found that the peak currents of the complex are an irreversible adsorption wave.The adsorbed amount of T(p-OCH3)PP and Zn T(p-OCH3)PP on mercury electrode surface were 1.41×10-10 and 6.77×10-11 mol/cm2, respectively as determined by chronoculometry.
2001, 18(9): 717-720
Abstract:
The quantum chemical descriptors, topological indices Am(Am1, Am2, Am3), molecular connectivity indices mxt and hydrophobic parameters for the thirty four HEPT derivatives were calculated.The algorithms orthogonal descriptors and Leaps-and-Bonds regression were performed for variable selection.Multiregression and the quasi-Newton neural network calculations have been carried out.The results obtained by using neural network are much better than those obtained by using multiregression.The activity mechanism has been discussed briefly.
The quantum chemical descriptors, topological indices Am(Am1, Am2, Am3), molecular connectivity indices mxt and hydrophobic parameters for the thirty four HEPT derivatives were calculated.The algorithms orthogonal descriptors and Leaps-and-Bonds regression were performed for variable selection.Multiregression and the quasi-Newton neural network calculations have been carried out.The results obtained by using neural network are much better than those obtained by using multiregression.The activity mechanism has been discussed briefly.
2001, 18(9): 721-725
Abstract:
Polyoxymethylene/organo montmorillonite (POM/Mont) nanocomposites were prepared by melt direct intercalation, and the basal spacing of montmorillonite was detected by X-ray diffractometer(XRD).The nonisothermal crystallization kinetics of polyoxymethylene(POM) and POM/Mont nanocomposite were investigated by differential scanning calorimetry(DSC).The Jeziorny, Ozawa and Liu methods were employed to analyze the DSC data.The results showed that both Jeziorny and Liu methods could describe this system very well.The activation energies evaluated by Cebe method were 334.6 kJ/mol and 196.9 kJ/mol for the nonisothermal crystallization of POM and POM/Mont nanocomposite, respectively.Intercalation of organic montmorillonite into POM decreased its activation energy and half time of crystallization, playing a role as a nucleating agent for nonisothermal crystallization of POM.
Polyoxymethylene/organo montmorillonite (POM/Mont) nanocomposites were prepared by melt direct intercalation, and the basal spacing of montmorillonite was detected by X-ray diffractometer(XRD).The nonisothermal crystallization kinetics of polyoxymethylene(POM) and POM/Mont nanocomposite were investigated by differential scanning calorimetry(DSC).The Jeziorny, Ozawa and Liu methods were employed to analyze the DSC data.The results showed that both Jeziorny and Liu methods could describe this system very well.The activation energies evaluated by Cebe method were 334.6 kJ/mol and 196.9 kJ/mol for the nonisothermal crystallization of POM and POM/Mont nanocomposite, respectively.Intercalation of organic montmorillonite into POM decreased its activation energy and half time of crystallization, playing a role as a nucleating agent for nonisothermal crystallization of POM.
2001, 18(9): 726-730
Abstract:
Mono-size crosslinked polystyrene microspheres(CPS) in average diameter of 4 μm were prepared in a mixture of ethanol and water.The effects of mass fraction of styrene, divinylbenzene and stabilizer PVP on the average particle diameter(Dn) and its distribution, polymerization kinetics and variation of particle numbers in the polymerization were studied.In a certain concentration range, the polymerization rate and average particle size increased with increasing the concentrations of styrene and divinylbenzene, but the particle size distributions broadened and the particle number decreased dramatically.The concentration of stabilizer has no obvious effects on the polymerization rate and particle size distribution, but the particle size decreased and the particle number increased with increasing the stabilizer PVP concentration.
Mono-size crosslinked polystyrene microspheres(CPS) in average diameter of 4 μm were prepared in a mixture of ethanol and water.The effects of mass fraction of styrene, divinylbenzene and stabilizer PVP on the average particle diameter(Dn) and its distribution, polymerization kinetics and variation of particle numbers in the polymerization were studied.In a certain concentration range, the polymerization rate and average particle size increased with increasing the concentrations of styrene and divinylbenzene, but the particle size distributions broadened and the particle number decreased dramatically.The concentration of stabilizer has no obvious effects on the polymerization rate and particle size distribution, but the particle size decreased and the particle number increased with increasing the stabilizer PVP concentration.
2001, 18(9): 731-735
Abstract:
The theoretical and experimental studies on extraction of tryptophan with tri-n-octylmethylammonium chloride(TOMAC) have been made.An equilibrium model and equations relating to the calculation of distribution coefficient DA,id and H+ concentration change in ideal conditions were derived.The distribution coefficient in practical processes DAP was corelated with the distribution coefficient in ideal condition DA,id and a modificative factor f.The calculated results show that the calculation values DAP,cal are in good agreement with experimental ones.
The theoretical and experimental studies on extraction of tryptophan with tri-n-octylmethylammonium chloride(TOMAC) have been made.An equilibrium model and equations relating to the calculation of distribution coefficient DA,id and H+ concentration change in ideal conditions were derived.The distribution coefficient in practical processes DAP was corelated with the distribution coefficient in ideal condition DA,id and a modificative factor f.The calculated results show that the calculation values DAP,cal are in good agreement with experimental ones.
2001, 18(9): 736-740
Abstract:
A simple and reliable electroanalytical method for the fast determination of different aluminum species(total AlT, acid soluble Alr, monomeric Ala, inorganic monomeric Ali and organic monomeric Alo) in natural waters by a.c.oscillopolarography using chlorosulfophenol-S(SCPS) is described.The method was successfully applied to analyze different species of Al in 20 real samples.A program using C language designed by authors was applied to prove the theoretical foundation of the proposed method.The program was also applied to compare three kinds of reagents with different structures to ascertain the optimum pH range for speciation of Al in real water.It is concluded that the complexing ability of a certain reagent with Al mainly depends on the complexing constant and acid dissociation constant Ka, as well as the chemical structure of the ligands.
A simple and reliable electroanalytical method for the fast determination of different aluminum species(total AlT, acid soluble Alr, monomeric Ala, inorganic monomeric Ali and organic monomeric Alo) in natural waters by a.c.oscillopolarography using chlorosulfophenol-S(SCPS) is described.The method was successfully applied to analyze different species of Al in 20 real samples.A program using C language designed by authors was applied to prove the theoretical foundation of the proposed method.The program was also applied to compare three kinds of reagents with different structures to ascertain the optimum pH range for speciation of Al in real water.It is concluded that the complexing ability of a certain reagent with Al mainly depends on the complexing constant and acid dissociation constant Ka, as well as the chemical structure of the ligands.
2001, 18(9): 741-745
Abstract:
Reforming of CH4 with CO2 to give syngas over Ni/SiO2, Co/SiO2 and Ni Co/SiO2 catalysts has been studied by activity evaluation using TPO, TPR and CO2-TPD techniques.It is found that the catalysts without pre reduction decreased in their activities following the order of Ni Co/SiO2~Ni/SiO2>>Co/SiO2, and Ni Co/SiO2 was much less sensitive to coking and more stable than Ni/SiO2 catalyst.The CH4 conversion over Ni Co/SiO2 catalyst increased with time in stream during the first 1 h period of reaction and then remained invariable with time in stream for 9 h, while over Ni/SiO2 catalyst the CH4 conversion decreased continuously with reaction time and the reaction had to be stopped because of the reactor becoming completely plugged by carbon deposits after 6 h.In the case of Ni Co/SiO2 catalyst, Ni promoted the reduction of Co species, which was found beneficial to CO2 adsorption and suppression of less active carbon deposition.This is considered to be related to the excellent activity, stability and anti coking property of the bimetallic catalyst.
Reforming of CH4 with CO2 to give syngas over Ni/SiO2, Co/SiO2 and Ni Co/SiO2 catalysts has been studied by activity evaluation using TPO, TPR and CO2-TPD techniques.It is found that the catalysts without pre reduction decreased in their activities following the order of Ni Co/SiO2~Ni/SiO2>>Co/SiO2, and Ni Co/SiO2 was much less sensitive to coking and more stable than Ni/SiO2 catalyst.The CH4 conversion over Ni Co/SiO2 catalyst increased with time in stream during the first 1 h period of reaction and then remained invariable with time in stream for 9 h, while over Ni/SiO2 catalyst the CH4 conversion decreased continuously with reaction time and the reaction had to be stopped because of the reactor becoming completely plugged by carbon deposits after 6 h.In the case of Ni Co/SiO2 catalyst, Ni promoted the reduction of Co species, which was found beneficial to CO2 adsorption and suppression of less active carbon deposition.This is considered to be related to the excellent activity, stability and anti coking property of the bimetallic catalyst.
2001, 18(9): 746-748
Abstract:
Disodium polyepoxysuccinate that effectively inhibits the formation of scale was synthesized from disodium epoxysuccinate by treatment with alkaline calcium compound.The effect on scale inhibiting property of the product from amount and feed times of catalyst, the reaction temperature, the reaction time were investigated.The optimum reaction conditions are as follows:1.18g catalyst, 95℃ and 3 hours of synthesis.
Disodium polyepoxysuccinate that effectively inhibits the formation of scale was synthesized from disodium epoxysuccinate by treatment with alkaline calcium compound.The effect on scale inhibiting property of the product from amount and feed times of catalyst, the reaction temperature, the reaction time were investigated.The optimum reaction conditions are as follows:1.18g catalyst, 95℃ and 3 hours of synthesis.
2001, 18(9): 749-751
Abstract:
The hydrophobic starch derivatives were prepared by the reaction between the dodecenyl succinic anhydrides(DDSA) and starch.The effects of starch content in water, anhydride content, pH values and temperature on the reaction efficiency were studied.Adding the anhydride to the starch slurry in pre emulsified form makes the reaction faster and more efficiently.
The hydrophobic starch derivatives were prepared by the reaction between the dodecenyl succinic anhydrides(DDSA) and starch.The effects of starch content in water, anhydride content, pH values and temperature on the reaction efficiency were studied.Adding the anhydride to the starch slurry in pre emulsified form makes the reaction faster and more efficiently.
2001, 18(9): 752-754
Abstract:
The oxidative carbonylation of phenol to diphenyl carbonate catalyzed by Pd-Co, Pd-Cu and Pd-Mn catalyst systems has been studied with the addition of other components such as benzoquinone, Bu2NBr and molecular sieve.The results show that Bu2NBr plays a very important role and Pd Mn catalyst has the highest activity among the three kinds of the catalysts studied.When the reaction is catalyzed by PdMn catalyst at n(PdCl2):n(Mn(OAc)2):n(Bu4NBr):n(benzoquinone)=1:1:10:25, t=100℃, P=2.5 MPa(PCO/PO2=4:1), reaction time 8 h, the yield of DPC is 7.23%.The yield of DPC is found to be increased with increase in total pressure of reactor and could be reached to 10.20% at total pressure of 3.5 MPa.
The oxidative carbonylation of phenol to diphenyl carbonate catalyzed by Pd-Co, Pd-Cu and Pd-Mn catalyst systems has been studied with the addition of other components such as benzoquinone, Bu2NBr and molecular sieve.The results show that Bu2NBr plays a very important role and Pd Mn catalyst has the highest activity among the three kinds of the catalysts studied.When the reaction is catalyzed by PdMn catalyst at n(PdCl2):n(Mn(OAc)2):n(Bu4NBr):n(benzoquinone)=1:1:10:25, t=100℃, P=2.5 MPa(PCO/PO2=4:1), reaction time 8 h, the yield of DPC is 7.23%.The yield of DPC is found to be increased with increase in total pressure of reactor and could be reached to 10.20% at total pressure of 3.5 MPa.
2001, 18(9): 755-757
Abstract:
Co3O4 nanoparticles were prepared by mixing polyvinylalcohol(PVA)and Co(NO3)2 in a mole ratio of 1:3~4,at 100~130℃ to evaporate and remove water,and calcining at 400℃ for 2 h.The structure,crystal type and surface appearance were characterized by IR,XRD and TEM.The results showed that metal carbonate was formed using the polymer combustion methods,and the Co3O4 gave a cubic polygon appearance.Agglomerate free,well dispersive Co3O4 nanoparticles with the cubic structure and the average size of ca.33 nm could be obtained from carbonated precursor by this simple and economical methods
Co3O4 nanoparticles were prepared by mixing polyvinylalcohol(PVA)and Co(NO3)2 in a mole ratio of 1:3~4,at 100~130℃ to evaporate and remove water,and calcining at 400℃ for 2 h.The structure,crystal type and surface appearance were characterized by IR,XRD and TEM.The results showed that metal carbonate was formed using the polymer combustion methods,and the Co3O4 gave a cubic polygon appearance.Agglomerate free,well dispersive Co3O4 nanoparticles with the cubic structure and the average size of ca.33 nm could be obtained from carbonated precursor by this simple and economical methods
2001, 18(9): 758-760
Abstract:
The structure change of HDPE under ultraviolet irradiation in air and O2 atmosphere was studied by elemental analysis, FTIR, XPS, GPC.The oxygen containing groups such as C=O C-O were observed in molecular chains of HDPE after irradiation.The contents of C=O and C-O increase with irradiation time.The O2 acceleretes the rate of HDPE functionalization.During ultraviolet irradiation, the molecular weight of HDPE is decreased and its MWD becomes narrow.
The structure change of HDPE under ultraviolet irradiation in air and O2 atmosphere was studied by elemental analysis, FTIR, XPS, GPC.The oxygen containing groups such as C=O C-O were observed in molecular chains of HDPE after irradiation.The contents of C=O and C-O increase with irradiation time.The O2 acceleretes the rate of HDPE functionalization.During ultraviolet irradiation, the molecular weight of HDPE is decreased and its MWD becomes narrow.
2001, 18(9): 761-763
Abstract:
The solid complex of zinc L-threonate has been prepared from the reaction mixture of L-ascorbic acid, calcium carbonate and hydrogen peroxide in water at 0~3℃.It is purified by methyl alcohol extraction under reduced pressure.The composition of the complex is determined by chemical and elemental analyses and its formula fits Zn(C4H7O5)2.The purity of the complex is 99.60% by HPLC.The IR spectra indicate that Zn2+ in the complex coordinates to oxygen atom of the carbonyl group and oxygen atom of the carboxyl group, while the proton of the carboxyl group is dissociated.It is assumed that the coordination number of Zn2+ is 4.The TG DTG results show that the intermediate and final products of the thermal decomposition of the complex are Zn(CH3COO)2 and ZnO, respectively.
The solid complex of zinc L-threonate has been prepared from the reaction mixture of L-ascorbic acid, calcium carbonate and hydrogen peroxide in water at 0~3℃.It is purified by methyl alcohol extraction under reduced pressure.The composition of the complex is determined by chemical and elemental analyses and its formula fits Zn(C4H7O5)2.The purity of the complex is 99.60% by HPLC.The IR spectra indicate that Zn2+ in the complex coordinates to oxygen atom of the carbonyl group and oxygen atom of the carboxyl group, while the proton of the carboxyl group is dissociated.It is assumed that the coordination number of Zn2+ is 4.The TG DTG results show that the intermediate and final products of the thermal decomposition of the complex are Zn(CH3COO)2 and ZnO, respectively.
2001, 18(9): 764-766
Abstract:
Five amido-thiol-tin compounds, bis-N,N-dialkylaminocarbonylethyl tin-bis-iso-octyl sufenylacetates, were prepared by reacting esters thiol tin or ester tin dichloride with secondary amines.The structures of the compounds were determined by IR,1HNMR,119Sn NMR and elemental analysis.The new compounds have a good heat stability for PVC resin, among them bis-N,N-dihydroxyethylaminocarbonylethyl-tin-bis-iso-octyl sufenylacetate is the best one.
Five amido-thiol-tin compounds, bis-N,N-dialkylaminocarbonylethyl tin-bis-iso-octyl sufenylacetates, were prepared by reacting esters thiol tin or ester tin dichloride with secondary amines.The structures of the compounds were determined by IR,1HNMR,119Sn NMR and elemental analysis.The new compounds have a good heat stability for PVC resin, among them bis-N,N-dihydroxyethylaminocarbonylethyl-tin-bis-iso-octyl sufenylacetate is the best one.
