Login In
2000 Volume 17 Issue 6
2000, 17(6): 581-584
Abstract:
The effects of temperature on the copolymer micellization in octanol-xylene and on the solubilization of water are examined for poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)(PE6200) and poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)(25R4) copolymers. The "reverse" critical micelle concentrations(CMC) are determined. An increase in temperature favours the solubilization of copolymers in organic solvent, resulting in an increase of CMC of the copolymers. A linear relationship between ln XCMC and absolute temperature is observed, from which some thermodynamic parameters of the micellization are estimated. The negative ΔGps0 indicates that thermodynamically stable micelles are formed spontaneously by the block copolymers in octanol-xylene. The ΔHps0 and ΔSps0 values are also negative, showing that the formation of micelles in p-xylene is exothermic and entropically unfavorable.
The effects of temperature on the copolymer micellization in octanol-xylene and on the solubilization of water are examined for poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)(PE6200) and poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)(25R4) copolymers. The "reverse" critical micelle concentrations(CMC) are determined. An increase in temperature favours the solubilization of copolymers in organic solvent, resulting in an increase of CMC of the copolymers. A linear relationship between ln XCMC and absolute temperature is observed, from which some thermodynamic parameters of the micellization are estimated. The negative ΔGps0 indicates that thermodynamically stable micelles are formed spontaneously by the block copolymers in octanol-xylene. The ΔHps0 and ΔSps0 values are also negative, showing that the formation of micelles in p-xylene is exothermic and entropically unfavorable.
2000, 17(6): 585-588
Abstract:
The LaFeO3 and a series of Sr-doped compoundsLa1-xSrxFeO3(x=0.01,0.02,0.03,0.04,0.05) were prepared by a citrate method and the photodegradation of some water-soluble dyes were carried out over them by using a 450 W Hg lamp as irradiation source. The catalytic activities of LaFeO3 and La1-xSrxFeO3 were compared also with IR, UV-Vis and acoustic spectrum measurements. The results revealed that the doped compounds showed a obvious greater catalytic activity than undoped one for dye photodegradation.
The LaFeO3 and a series of Sr-doped compoundsLa1-xSrxFeO3(x=0.01,0.02,0.03,0.04,0.05) were prepared by a citrate method and the photodegradation of some water-soluble dyes were carried out over them by using a 450 W Hg lamp as irradiation source. The catalytic activities of LaFeO3 and La1-xSrxFeO3 were compared also with IR, UV-Vis and acoustic spectrum measurements. The results revealed that the doped compounds showed a obvious greater catalytic activity than undoped one for dye photodegradation.
2000, 17(6): 589-592
Abstract:
Six charge-transfer salts,[NMPH]3PMoxW12-xO40·CH3CN(x=0,1,3,9,11,12) were synthesized from H3PMoxW12-xO40·nH2O and N-methylpyrrolidone and characterized by elemental analysis and IR spectra. The results suggest that there is a strong interaction between anions and organic cations in solid compounds. The charge-transfer in the compounds will take place under irradiation of light and result in oxidation of organic molecules and reduction of anions. The ESR results indicate the one electron step reduction of anions. The second-order and third-order nonlinear optical property measurements indicate that the SHG and the susceptibilities of the charge-transfer salts increase with the increase of tungsten content in molecule.
Six charge-transfer salts,[NMPH]3PMoxW12-xO40·CH3CN(x=0,1,3,9,11,12) were synthesized from H3PMoxW12-xO40·nH2O and N-methylpyrrolidone and characterized by elemental analysis and IR spectra. The results suggest that there is a strong interaction between anions and organic cations in solid compounds. The charge-transfer in the compounds will take place under irradiation of light and result in oxidation of organic molecules and reduction of anions. The ESR results indicate the one electron step reduction of anions. The second-order and third-order nonlinear optical property measurements indicate that the SHG and the susceptibilities of the charge-transfer salts increase with the increase of tungsten content in molecule.
2000, 17(6): 593-597
Abstract:
An experimental investigation on syngas preparation from CH4 and CO2 at ambient temperature and pressure in corona plasma has been performed. The conversions of CH4 and CO2 were found to be dependent on the energy density(input energy per mole feed), ratio of CH4 to CO2 in feed and flow rate of feed gases. For n(CH4)/n(CO2)=1/2 at 0.1 MPa and energy density of 1050 kJ/mol(in which temperature was lower than 500 K) the conversions of CH4 and CO2 were more than 60% and 50%, respectively. These experimental values exceed the calculated values based on chemical equilibrium theory. The ratio of H2 to CO in products increased with the increasing of ratio of CH4 to CO2 in feed gases. A radical reacti on mechanism was suggested.
An experimental investigation on syngas preparation from CH4 and CO2 at ambient temperature and pressure in corona plasma has been performed. The conversions of CH4 and CO2 were found to be dependent on the energy density(input energy per mole feed), ratio of CH4 to CO2 in feed and flow rate of feed gases. For n(CH4)/n(CO2)=1/2 at 0.1 MPa and energy density of 1050 kJ/mol(in which temperature was lower than 500 K) the conversions of CH4 and CO2 were more than 60% and 50%, respectively. These experimental values exceed the calculated values based on chemical equilibrium theory. The ratio of H2 to CO in products increased with the increasing of ratio of CH4 to CO2 in feed gases. A radical reacti on mechanism was suggested.
2000, 17(6): 598-602
Abstract:
The effects of concentration, deacetylation degree, molecular weight and pH of medium on the antibacterial activity of chitosan against Esherichia Coli have been investigated. The results showed that the antibacterial activity of chitosan increased with increase in concentration and deacetylation degree and it first increased with increasing molecular weight, reached a maximum at Mw=9.16×10.4 and pH=6.5 and then decreased with further increase in molecular weight. The effects of chitosan on the E.Coli was studied morphologically by confocal laser scanning microscopy and SEM with the results that the E.Coli cells were deformed and autolysed in contact with chitosan samples.
The effects of concentration, deacetylation degree, molecular weight and pH of medium on the antibacterial activity of chitosan against Esherichia Coli have been investigated. The results showed that the antibacterial activity of chitosan increased with increase in concentration and deacetylation degree and it first increased with increasing molecular weight, reached a maximum at Mw=9.16×10.4 and pH=6.5 and then decreased with further increase in molecular weight. The effects of chitosan on the E.Coli was studied morphologically by confocal laser scanning microscopy and SEM with the results that the E.Coli cells were deformed and autolysed in contact with chitosan samples.
2000, 17(6): 603-606
Abstract:
The usefulness and characteristics of some methods for in situ monitoring gelation dynamics have been studied, taking glutaraldehyde(Glu) crosslinked chitosan(CS) in acetic acid medium as a model system. It has been shown that the viscosity method is simple and direct. But it is unlikely to monitor the changes occurring after the gelling point of a gelation system. In addition, there is a perturbation to the gelling process from the rotationary viscosity measurements. The electroconductivity and photometric methods monitor the crosslin-king reaction, rather than the rheological changes. Therefore, the results may not be in consistent with that perceived through the senses. Among the methods tested, fluorescence probe method appears the first choice to monitor the gelation dynamics of various gelling systems due to the great number of probes and related fluorescence properties.
The usefulness and characteristics of some methods for in situ monitoring gelation dynamics have been studied, taking glutaraldehyde(Glu) crosslinked chitosan(CS) in acetic acid medium as a model system. It has been shown that the viscosity method is simple and direct. But it is unlikely to monitor the changes occurring after the gelling point of a gelation system. In addition, there is a perturbation to the gelling process from the rotationary viscosity measurements. The electroconductivity and photometric methods monitor the crosslin-king reaction, rather than the rheological changes. Therefore, the results may not be in consistent with that perceived through the senses. Among the methods tested, fluorescence probe method appears the first choice to monitor the gelation dynamics of various gelling systems due to the great number of probes and related fluorescence properties.
2000, 17(6): 607-610
Abstract:
Some Schiff base complexes:Na[CuLAc]·3/2H2O, Na[ZnLAc]·3/2H2O, Na[CoLAc]·3/2H2O, where L=methionine-o-vaniline Schiff base, have been synthesized and characterized by elemental analysis, molar conductance, thermal analysis, infrared spectrum, electronic spectrum and EPR spectrum measurements. Properties of NaHL and the complexes in scavenging O2·- have been investigated.
Some Schiff base complexes:Na[CuLAc]·3/2H2O, Na[ZnLAc]·3/2H2O, Na[CoLAc]·3/2H2O, where L=methionine-o-vaniline Schiff base, have been synthesized and characterized by elemental analysis, molar conductance, thermal analysis, infrared spectrum, electronic spectrum and EPR spectrum measurements. Properties of NaHL and the complexes in scavenging O2·- have been investigated.
2000, 17(6): 611-614
Abstract:
The nanocrystal T-Fe2O3 with an average size of about 30 nm was prepared by a sol-gel method in iron nitrate and 2-methoxyethanol solution. The product was characterized by TEM, XRD and TG-DTA. The results showed that addition of sodium dodecylsulfonate(SDS) into the system favourd the formation of T-Fe2O3 phase and the gelation time was reduced greatly by adding tetrabutyl titanate in solution. By using TESi instead of TBTi, the product is a mixture of spinel V-Fe2O3 and T-Fe2O3, with the former as a main crystal phase.
The nanocrystal T-Fe2O3 with an average size of about 30 nm was prepared by a sol-gel method in iron nitrate and 2-methoxyethanol solution. The product was characterized by TEM, XRD and TG-DTA. The results showed that addition of sodium dodecylsulfonate(SDS) into the system favourd the formation of T-Fe2O3 phase and the gelation time was reduced greatly by adding tetrabutyl titanate in solution. By using TESi instead of TBTi, the product is a mixture of spinel V-Fe2O3 and T-Fe2O3, with the former as a main crystal phase.
2000, 17(6): 615-619
Abstract:
The surface property of copper phthalocyanine(CuPC) was modified by plasma-treatment, polymer adsorption and addition of Na2SO4 and urea. The XPS results indicated the formation of hydroxyl and carboxyl groups on the pigment surface as a result of plasma treatment. The presence of the polar groups increased the adsorbability of polymer. Addition of Na2SO4 and urea in the CuPC system increased the thickness of the adsorbed layer. All these treatment approaches favoured the dispersibility of CuPC in water, enhancing the stability of the pigment suspension.
The surface property of copper phthalocyanine(CuPC) was modified by plasma-treatment, polymer adsorption and addition of Na2SO4 and urea. The XPS results indicated the formation of hydroxyl and carboxyl groups on the pigment surface as a result of plasma treatment. The presence of the polar groups increased the adsorbability of polymer. Addition of Na2SO4 and urea in the CuPC system increased the thickness of the adsorbed layer. All these treatment approaches favoured the dispersibility of CuPC in water, enhancing the stability of the pigment suspension.
2000, 17(6): 620-623
Abstract:
Cu(Ⅱ) precipitates in aqueous solution by ammonium thiocyanate and hexadocyltrimethyl ammonium bromide. In the presence of sodium nitrate the precipitates is floatated and Cu(Ⅱ) can be completely separated by floatation even in the presence of Fe(Ⅲ), Al(Ⅲ), Co(Ⅱ), Ni(Ⅱ) and Mn(Ⅱ). The method has advantages covering both the organic and inorganic solvent floatation methods and econimics in surfactants and salts.
Cu(Ⅱ) precipitates in aqueous solution by ammonium thiocyanate and hexadocyltrimethyl ammonium bromide. In the presence of sodium nitrate the precipitates is floatated and Cu(Ⅱ) can be completely separated by floatation even in the presence of Fe(Ⅲ), Al(Ⅲ), Co(Ⅱ), Ni(Ⅱ) and Mn(Ⅱ). The method has advantages covering both the organic and inorganic solvent floatation methods and econimics in surfactants and salts.
2000, 17(6): 624-627
Abstract:
Peroxide crosslinking of metallocene syndiotactic polypropylene(sPP) has been performed in the presence of divinyl benzene(DVB), ethyleneglycol dimethylacrylate(EGDMA), trimethylol propane trimethylacrylate(TMPTMA) and triallyl isocyanuate(TAIC) as coagents. The polyfunctional monomers were found to prohibite the thermal degradation of sPP. The crosslinked sPP with higher gel fraction were obtained in the system comprised of BPO and DVB. The gel fraction of the crosslinked sPP increased with increase in BPO and/or DVB. The gelation rate increased linearly with the concentration of DVB and BPO, following first order kinetics. The apparent activation energy of crosslinking was 62.5 kJ/mol as determined from the relations between gelation rate and crosslinking temperature.
Peroxide crosslinking of metallocene syndiotactic polypropylene(sPP) has been performed in the presence of divinyl benzene(DVB), ethyleneglycol dimethylacrylate(EGDMA), trimethylol propane trimethylacrylate(TMPTMA) and triallyl isocyanuate(TAIC) as coagents. The polyfunctional monomers were found to prohibite the thermal degradation of sPP. The crosslinked sPP with higher gel fraction were obtained in the system comprised of BPO and DVB. The gel fraction of the crosslinked sPP increased with increase in BPO and/or DVB. The gelation rate increased linearly with the concentration of DVB and BPO, following first order kinetics. The apparent activation energy of crosslinking was 62.5 kJ/mol as determined from the relations between gelation rate and crosslinking temperature.
2000, 17(6): 628-632
Abstract:
The effects of Co(OH)2 and Ni powder added into nickel hydroxide electrode on its performance were studied by triangle wave potential sweeping, XRD and constant-current charging-discharging techniques. The results indicated that nickel hydroxide electrode containing 8%Co(OH)2 and 13% Ni powder showed the highest discharge capacity and the lowest expansion at charging-discharging runs.
The effects of Co(OH)2 and Ni powder added into nickel hydroxide electrode on its performance were studied by triangle wave potential sweeping, XRD and constant-current charging-discharging techniques. The results indicated that nickel hydroxide electrode containing 8%Co(OH)2 and 13% Ni powder showed the highest discharge capacity and the lowest expansion at charging-discharging runs.
2000, 17(6): 633-635
Abstract:
Nanosized spinel LiMn2O4 was prepared by a sol-gel method. The preparation process was monitored by XRD, BET, DTA, TGA and TEM observations. It is found that at temperature higher than 350℃ the spinel phase of the samples could be detected by XRD, which is lower than that temperature in common solid-state preparation. The diameters of the samples calculated by Sherrer equation were increased with the temperature of calcination.
Nanosized spinel LiMn2O4 was prepared by a sol-gel method. The preparation process was monitored by XRD, BET, DTA, TGA and TEM observations. It is found that at temperature higher than 350℃ the spinel phase of the samples could be detected by XRD, which is lower than that temperature in common solid-state preparation. The diameters of the samples calculated by Sherrer equation were increased with the temperature of calcination.
2000, 17(6): 636-638
Abstract:
Pyrrolidine dithiocarbamic ammonium can cause a sensitive incision on the cathodic branch of dE/dt-E oscillogram at -0.80 V(vs.SCE) in 0.1 mol/L KCl solution. When Co2+、Ni2+、Cd2+、Ga3+ and In3+ are present in KCl solution containing pyrrolidine dithiocarbamic ammonium the depth of the incision varies. A linear relationship between the incision depth and concentration of the metal ions is established and the second-order differential simple oscillographic voltammetry is applied to quantitative determination for these ions. The cobalt ion in molecular sieve is also determined with satisfactory results.
Pyrrolidine dithiocarbamic ammonium can cause a sensitive incision on the cathodic branch of dE/dt-E oscillogram at -0.80 V(vs.SCE) in 0.1 mol/L KCl solution. When Co2+、Ni2+、Cd2+、Ga3+ and In3+ are present in KCl solution containing pyrrolidine dithiocarbamic ammonium the depth of the incision varies. A linear relationship between the incision depth and concentration of the metal ions is established and the second-order differential simple oscillographic voltammetry is applied to quantitative determination for these ions. The cobalt ion in molecular sieve is also determined with satisfactory results.
2000, 17(6): 639-641
Abstract:
The title copolymers and their water soluble carboxylates were synthesized from methyl acrylate and cinchonine, quinine in CHCl3, respectively, using azo-bis-isobutyroni-trile as initiator. The four compounds as chiral amine ligands being reacted with dimethylglyoximatocobalt(Ⅱ) gave four complexes, which were used for catalytic asymmetric hydrogenation of acetamidocinamic acid, giving considerably possitive results.
The title copolymers and their water soluble carboxylates were synthesized from methyl acrylate and cinchonine, quinine in CHCl3, respectively, using azo-bis-isobutyroni-trile as initiator. The four compounds as chiral amine ligands being reacted with dimethylglyoximatocobalt(Ⅱ) gave four complexes, which were used for catalytic asymmetric hydrogenation of acetamidocinamic acid, giving considerably possitive results.
2000, 17(6): 642-644
Abstract:
The polymerization of methyl methacrylate was first studied using (diisopropylamido)bis(indenyl) lanthanides as a single-component catalyst.A mechanism is proposed to the polymerization initiation of MMA.
The polymerization of methyl methacrylate was first studied using (diisopropylamido)bis(indenyl) lanthanides as a single-component catalyst.A mechanism is proposed to the polymerization initiation of MMA.
2000, 17(6): 645-647
Abstract:
The effects of impregnation and reduction conditions on the particle size of Pt and structure of Pt/C catalyst were investigated by TEM, XRD and rotating thin-layer electrode techniques. The results showed that reductants affected the particle size and crystal face of platinum in the catalyst and Pt/C catalyst prepared from BP-2000 and by using HCHO as reductant showed a good electrocatalytic activity.
The effects of impregnation and reduction conditions on the particle size of Pt and structure of Pt/C catalyst were investigated by TEM, XRD and rotating thin-layer electrode techniques. The results showed that reductants affected the particle size and crystal face of platinum in the catalyst and Pt/C catalyst prepared from BP-2000 and by using HCHO as reductant showed a good electrocatalytic activity.
2000, 17(6): 648-650
Abstract:
Three poly(aryl ether sulfone)s containing 1,4-naphthylene moiety were prepared by the nucleophilic polycondensation of 1-chloro-4-(4-chlorobenzenesulfonyl)naphthalene(CCBSN) with 4,4'-isopropylidene diphenol(BPA), 1,4-hydroquinone(HQ) and 4-(4-hydroxyphenyl)(2H) phthalazin-1-one(DHPZ), respectively. The polymers were characterized by FT-IR, 1H NMR, WAXD and TGA techniques. The polymers obtained had high glass transition temperatures and good thermal stability. All the polymers were soluble in most common organic solvents.
Three poly(aryl ether sulfone)s containing 1,4-naphthylene moiety were prepared by the nucleophilic polycondensation of 1-chloro-4-(4-chlorobenzenesulfonyl)naphthalene(CCBSN) with 4,4'-isopropylidene diphenol(BPA), 1,4-hydroquinone(HQ) and 4-(4-hydroxyphenyl)(2H) phthalazin-1-one(DHPZ), respectively. The polymers were characterized by FT-IR, 1H NMR, WAXD and TGA techniques. The polymers obtained had high glass transition temperatures and good thermal stability. All the polymers were soluble in most common organic solvents.
2000, 17(6): 651-653
Abstract:
The title compounds were synthesized by oxidative dimerization of p-nitrotoluene. The effects of solvents, bases and oxidizing agents on the dimerization were investigated. The results showed that by selecting appropriate solvents, oxidizing agents, base catalysts and controlling technical conditions the yields of dinitrodibenzyl and dinitrostilbene could be reached 89.4% and 74.6%, respectively.
The title compounds were synthesized by oxidative dimerization of p-nitrotoluene. The effects of solvents, bases and oxidizing agents on the dimerization were investigated. The results showed that by selecting appropriate solvents, oxidizing agents, base catalysts and controlling technical conditions the yields of dinitrodibenzyl and dinitrostilbene could be reached 89.4% and 74.6%, respectively.
2000, 17(6): 654-656
Abstract:
Silica gel luminophor containing 1,10-phenanthroline complex with europium m-methylbenzoate, Eu(m-MBA)3phen·H2O was prepared by a sol-gel method. The thermal decomposition, excitation and emission spectra of the gel phosphor were measured and compared with that of the solid complex powder. The thermal st ability of the complex was found enhanced in SiO2 host matrix and the luminescence intensity remained unchanged.
Silica gel luminophor containing 1,10-phenanthroline complex with europium m-methylbenzoate, Eu(m-MBA)3phen·H2O was prepared by a sol-gel method. The thermal decomposition, excitation and emission spectra of the gel phosphor were measured and compared with that of the solid complex powder. The thermal st ability of the complex was found enhanced in SiO2 host matrix and the luminescence intensity remained unchanged.
2000, 17(6): 657-659
Abstract:
The distribution of mitomycin(MIT) for injection in aqueous surfactant two phases(ASTP), consisted of cetyltrimethylammonium bromide(CTAB) and sodium oleate(SO) has been studied by spectrophotometry. The results show that for ASTP system with a certain ratio of CTAB to SO the volume of the upper phase decreased and that of the lower phase increased with increase of MIT added, while the distribution ratio Kd and single extraction yield Y of MIT in two phases remained approximately constant.
The distribution of mitomycin(MIT) for injection in aqueous surfactant two phases(ASTP), consisted of cetyltrimethylammonium bromide(CTAB) and sodium oleate(SO) has been studied by spectrophotometry. The results show that for ASTP system with a certain ratio of CTAB to SO the volume of the upper phase decreased and that of the lower phase increased with increase of MIT added, while the distribution ratio Kd and single extraction yield Y of MIT in two phases remained approximately constant.
2000, 17(6): 660-662
Abstract:
A number of microorganisms in activated sludge in the process of waste water treatment were used for accumulating polyhydroxyalkanoates(PHA). Mixed bacteria and organic carbon source were used in microaerophilic-aerobic treatment of activated sludge and some cultural conditions:oxygen supply rate, attachment carbon source concentration and culture time were investigated. The PHAs obtained appeared a mixture of copolymers or heteropolymers with various monomer unites:3-hydroxybutyrate, 4-hydroxy-pentanoate, 3-hydroxydodecanoate, 3-hydroxy-tetradecanoate, 3-hydroxy-9-hexadecanoate, 3-hydroxyhe-xadecanoate, 3-hydroxy-11-octadecanoate, 3-hydroxy-9-octadecanoate, and 3-hydroxyocta-decanoate.
A number of microorganisms in activated sludge in the process of waste water treatment were used for accumulating polyhydroxyalkanoates(PHA). Mixed bacteria and organic carbon source were used in microaerophilic-aerobic treatment of activated sludge and some cultural conditions:oxygen supply rate, attachment carbon source concentration and culture time were investigated. The PHAs obtained appeared a mixture of copolymers or heteropolymers with various monomer unites:3-hydroxybutyrate, 4-hydroxy-pentanoate, 3-hydroxydodecanoate, 3-hydroxy-tetradecanoate, 3-hydroxy-9-hexadecanoate, 3-hydroxyhe-xadecanoate, 3-hydroxy-11-octadecanoate, 3-hydroxy-9-octadecanoate, and 3-hydroxyocta-decanoate.
2000, 17(6): 663-665
Abstract:
Seven p-dimethylaminobenzylidene dyes containing different acceptors have been synthesized and characterized by IR, 1H NMR, and elemental analysis. Their electronic absorption spectra in ethanol have been studied, their λmax values were in range of 448~492 nm.
Seven p-dimethylaminobenzylidene dyes containing different acceptors have been synthesized and characterized by IR, 1H NMR, and elemental analysis. Their electronic absorption spectra in ethanol have been studied, their λmax values were in range of 448~492 nm.
2000, 17(6): 666-668
Abstract:
The extraction of Co2+ with HEH[EHP] in kerosene from sulfate solution has been studied by a microcalorimetric method. The reaction heat has been determined from the power-time curves and the extraction equilibrium constant and thermokinetic parameters have been evaluated. The reaction rate constants and activation energies of the forward and reverse reactions have been calculated.
The extraction of Co2+ with HEH[EHP] in kerosene from sulfate solution has been studied by a microcalorimetric method. The reaction heat has been determined from the power-time curves and the extraction equilibrium constant and thermokinetic parameters have been evaluated. The reaction rate constants and activation energies of the forward and reverse reactions have been calculated.
2000, 17(6): 669-671
Abstract:
A series of polymer-polyol dispersions have been prepared from polyether polyol and poly(styrene-acrylonitrile). The rheological behavior and particle size of the dispersions have been measured. The flow curves of the dispersions indicated the non-Newtonian behavior of shear thickening to shear thinning. The particle size in dispersions are affected by macromer content, temperature and stirring rate in preparation.
A series of polymer-polyol dispersions have been prepared from polyether polyol and poly(styrene-acrylonitrile). The rheological behavior and particle size of the dispersions have been measured. The flow curves of the dispersions indicated the non-Newtonian behavior of shear thickening to shear thinning. The particle size in dispersions are affected by macromer content, temperature and stirring rate in preparation.
2000, 17(6): 672-674
Abstract:
Toluene-3,4-diamine was prepared by catalytical hydrogenation of 2-nitro-4-aminotoluene at atmospheric pressure and 40℃ in the presence of catalyst Urushibara-Ni in yield of 84.7%. The catalyst can be reused 10 times.
Toluene-3,4-diamine was prepared by catalytical hydrogenation of 2-nitro-4-aminotoluene at atmospheric pressure and 40℃ in the presence of catalyst Urushibara-Ni in yield of 84.7%. The catalyst can be reused 10 times.
2000, 17(6): 675-676
Abstract:
A facile method for the synthesis of title compound(CCFQ) in yield of 75% is reported. It is synthesized by reaction of 4,8-dichloroquin oline with 2-chloro-4-fluorophenol in the presence of KF/Al2O3. The product is confirmed by elemental analysis,1H NMR, IR and MS.
A facile method for the synthesis of title compound(CCFQ) in yield of 75% is reported. It is synthesized by reaction of 4,8-dichloroquin oline with 2-chloro-4-fluorophenol in the presence of KF/Al2O3. The product is confirmed by elemental analysis,1H NMR, IR and MS.
2000, 17(6): 677-679
Abstract:
U-cyclodextrin polymer cross-linked with epichlorohydrin was prepared. A colloid liquid with polyphenylsiloxane as diluent was prepared from U-cyclodextrin polymer(0.26 g) treated for 0.5 h by ultrasonication in mixed solvent (10 mL) of isopropyl ether, methylene dichloride and benzene (at volume ratio of 2:1:2). The U-CD polymer liquid is coated superdynamically on the capillary columns as stationary phase for gas chromatography. Chromatographic properties such as column efficiency, thermal stability, polarity and life of the stationary phase have been determined and xylene isomers and a series of enantiomers have been separated successfully on the capillary columns with prepared stationary phases.
U-cyclodextrin polymer cross-linked with epichlorohydrin was prepared. A colloid liquid with polyphenylsiloxane as diluent was prepared from U-cyclodextrin polymer(0.26 g) treated for 0.5 h by ultrasonication in mixed solvent (10 mL) of isopropyl ether, methylene dichloride and benzene (at volume ratio of 2:1:2). The U-CD polymer liquid is coated superdynamically on the capillary columns as stationary phase for gas chromatography. Chromatographic properties such as column efficiency, thermal stability, polarity and life of the stationary phase have been determined and xylene isomers and a series of enantiomers have been separated successfully on the capillary columns with prepared stationary phases.
