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1992 Volume 9 Issue 1
1992, 9(1): 1-6
Abstract:
In the terpolymerization of polyoxyethylene macromer, methyl methacrylate and butyl acrylate the polymerization rate and the effects of various factors on grafting efficiency and molecular weight of the terpolymers were studied. The terpolymers were purified by extractions and characterized by IR, NMR, DSC and membrane osmometry. The average grafting number was determined to be about 10. The terpolymers possess good emulsifying property, phase transfer catalytic ability and behave like a thermoplastic elastomer.
In the terpolymerization of polyoxyethylene macromer, methyl methacrylate and butyl acrylate the polymerization rate and the effects of various factors on grafting efficiency and molecular weight of the terpolymers were studied. The terpolymers were purified by extractions and characterized by IR, NMR, DSC and membrane osmometry. The average grafting number was determined to be about 10. The terpolymers possess good emulsifying property, phase transfer catalytic ability and behave like a thermoplastic elastomer.
1992, 9(1): 7-12
Abstract:
The synergistic extraction of Fe(Ⅲ) from (Na, H) Cl Solution with 1-Phenyl-3-methyl-4-benzoyl-pyrazotonl-5(PMBP, HL) and 2-ethylhexylphosphonic acid mono-2-ethyl-hexyl ester (HEH[EHP], HA) in xylene has been investigated. The composition of extracted complex has been determined to be FeL2A by the method of slope analysis, the mechanism of the synergistic extraction of Fe (Ⅲ) may be as follows:Fe3+2HL(0)+(1/2)(H2A2)(0)
FeL2A(0)+3H+ FeL3(0)+(1/2)(H2A2)(0)
FeL2A(0)+HL(0) Fe(HA2)3(0)+2HL(0)
FeL2A(0)+(5/2)(H2A2)(0) Their equilibrium constants and thermodynamic functions have been calculated to be:lgKAA=7.56±0.23 lgβ'=0.16 lgβ"=5.16 ΔH=21.76kJ/mol ΔG=-43.36kJ/mol ΔS=218.52J/mol.K, respectively. The IR and 1H NMR spectra of the synergistic extraction complex of Fe(Ⅲ) have been discussed as well.
The synergistic extraction of Fe(Ⅲ) from (Na, H) Cl Solution with 1-Phenyl-3-methyl-4-benzoyl-pyrazotonl-5(PMBP, HL) and 2-ethylhexylphosphonic acid mono-2-ethyl-hexyl ester (HEH[EHP], HA) in xylene has been investigated. The composition of extracted complex has been determined to be FeL2A by the method of slope analysis, the mechanism of the synergistic extraction of Fe (Ⅲ) may be as follows:Fe3+2HL(0)+(1/2)(H2A2)(0)
FeL2A(0)+3H+ FeL3(0)+(1/2)(H2A2)(0)FeL2A(0)+HL(0) Fe(HA2)3(0)+2HL(0)FeL2A(0)+(5/2)(H2A2)(0) Their equilibrium constants and thermodynamic functions have been calculated to be:lgKAA=7.56±0.23 lgβ'=0.16 lgβ"=5.16 ΔH=21.76kJ/mol ΔG=-43.36kJ/mol ΔS=218.52J/mol.K, respectively. The IR and 1H NMR spectra of the synergistic extraction complex of Fe(Ⅲ) have been discussed as well.
1992, 9(1): 13-20
Abstract:
Five 4-arm-and four 7-arm-star shaped polystyrene samples different in molecular weight have been prepared and examined by GPC combined viscosimetry. A theoretical treatment method is proposed to obtain the factor g'θ(=[η]b,θ/[η]l,θ.)from viscosity in good solvent. The difference between the factor g(=[η]b/[η]l) and g'θ,as well as the ∈-value in the relationship between g'θ, and gθ(=Sb,θ2/Si,θ2), (g'θ=gθε) have been discussed.The results verified that the ∈-value not only depends on the type of branching, but also depends on the degree of branching, ∈=1.487 and 1.14 for 4-arm and 7-arm star polystyrene, respectively. The difference between g' and g'θ is smaller for 4-arm star polystyrene, but is larger for 7-arm star polystyrene.
Five 4-arm-and four 7-arm-star shaped polystyrene samples different in molecular weight have been prepared and examined by GPC combined viscosimetry. A theoretical treatment method is proposed to obtain the factor g'θ(=[η]b,θ/[η]l,θ.)from viscosity in good solvent. The difference between the factor g(=[η]b/[η]l) and g'θ,as well as the ∈-value in the relationship between g'θ, and gθ(=Sb,θ2/Si,θ2), (g'θ=gθε) have been discussed.The results verified that the ∈-value not only depends on the type of branching, but also depends on the degree of branching, ∈=1.487 and 1.14 for 4-arm and 7-arm star polystyrene, respectively. The difference between g' and g'θ is smaller for 4-arm star polystyrene, but is larger for 7-arm star polystyrene.
1992, 9(1): 21-26
Abstract:
The crystallization behaviour of poly (ethylene oxide) (PEO)/poly (vinyl pyrrolidone) (PVP) blends has been investigated by using wide angle X-ray diffraction, differential scanning calorimeter and polarization microsecope,PEO/PVP blends have two glass transition temperature indicating the incompatibility of PEO and PVP components. The growth rate of spherulites (G) and the kinetic rate constant (K) decreased with the increase of PVP content. It was found that some sorts of morphological structure of spherulites of PEO/PVP appeared in relation with the composition of the blends and temperature.
The crystallization behaviour of poly (ethylene oxide) (PEO)/poly (vinyl pyrrolidone) (PVP) blends has been investigated by using wide angle X-ray diffraction, differential scanning calorimeter and polarization microsecope,PEO/PVP blends have two glass transition temperature indicating the incompatibility of PEO and PVP components. The growth rate of spherulites (G) and the kinetic rate constant (K) decreased with the increase of PVP content. It was found that some sorts of morphological structure of spherulites of PEO/PVP appeared in relation with the composition of the blends and temperature.
1992, 9(1): 27-31
Abstract:
The molar ratio of ethylene to vinylaeetate in ethylene-vinylacetate copolymers (EVA) was greater than 3:1, sothe side chains were deemed consisted mainly of ethyl and butyl branches. In this work, the 1378cm-1 band of CH3 side group in ataetie polypropylene was selected as key band for determination of the amount of branched chains in eopolymers, the 780cm-1 band of C2H5 group in 2-ethylhexane for ethyl branche, the 730cm-1 band of C4H9 side group in poly-a-hexane for butyl branches, respectively. A reasonable estimation of branched chain distribution has been carried our by following equations. nCH3/1000C=(0.50546 A1378/dt)-1.01966 nC2H5/1000C=(1.27161 A780/dt)-7.67873 nC4H9/1000C=(0.09113 A730/dt)-6.41352 nL.B/1000C=(0.50564 A1378/dt)-(1.27161 A780/dt)-(0.09113 A730/dt)+13.07259 The interference from CH3 in acetoxyl of VA is eliminated using band substraetion manipulation in FTIR and then the number average degree of branching has been determined by above equations. The results obtained were in good agreement with those obtained by1HNMR technique.
The molar ratio of ethylene to vinylaeetate in ethylene-vinylacetate copolymers (EVA) was greater than 3:1, sothe side chains were deemed consisted mainly of ethyl and butyl branches. In this work, the 1378cm-1 band of CH3 side group in ataetie polypropylene was selected as key band for determination of the amount of branched chains in eopolymers, the 780cm-1 band of C2H5 group in 2-ethylhexane for ethyl branche, the 730cm-1 band of C4H9 side group in poly-a-hexane for butyl branches, respectively. A reasonable estimation of branched chain distribution has been carried our by following equations. nCH3/1000C=(0.50546 A1378/dt)-1.01966 nC2H5/1000C=(1.27161 A780/dt)-7.67873 nC4H9/1000C=(0.09113 A730/dt)-6.41352 nL.B/1000C=(0.50564 A1378/dt)-(1.27161 A780/dt)-(0.09113 A730/dt)+13.07259 The interference from CH3 in acetoxyl of VA is eliminated using band substraetion manipulation in FTIR and then the number average degree of branching has been determined by above equations. The results obtained were in good agreement with those obtained by1HNMR technique.
1992, 9(1): 32-36
Abstract:
The melting of sphcrulitcs of nylon 1010 formed in isothermal crystallization has been studied by hot stage polarizing microscopy. The melting temperature (Tm) of the ringed positive spherulitcs was 182℃; that of the non-ringed positive spherulites, the mixed nonringed spherulitcs,the darker and brighter non ringed negative sphcrulitcs,were 203℃,202~205℃, and 204~210℃, respectively. Thus, the equilibrium melting temperature was 215℃ by extrapolating.
The melting of sphcrulitcs of nylon 1010 formed in isothermal crystallization has been studied by hot stage polarizing microscopy. The melting temperature (Tm) of the ringed positive spherulitcs was 182℃; that of the non-ringed positive spherulites, the mixed nonringed spherulitcs,the darker and brighter non ringed negative sphcrulitcs,were 203℃,202~205℃, and 204~210℃, respectively. Thus, the equilibrium melting temperature was 215℃ by extrapolating.
1992, 9(1): 37-41
Abstract:
The differential pulse cathodic stripping voltammetry has been employed to determine the concentration of 5-flourouracil (5-Fu) in serum.The interferences of electroactive substanees in serum can be eliminated by trichloroacetic acid. It is shown that 5-Fu can combine with Hg(Ⅱ) generated by anodic polarization forming an insoluble complex on electrode surface, The Hg-5-Fu complex is deemed to be a macromolecule with chain structure.
The differential pulse cathodic stripping voltammetry has been employed to determine the concentration of 5-flourouracil (5-Fu) in serum.The interferences of electroactive substanees in serum can be eliminated by trichloroacetic acid. It is shown that 5-Fu can combine with Hg(Ⅱ) generated by anodic polarization forming an insoluble complex on electrode surface, The Hg-5-Fu complex is deemed to be a macromolecule with chain structure.
1992, 9(1): 42-46
Abstract:
The adsorption and separation mechanism of Mo and W by Cl-P507 extraction resin have been investigated. The adsorption reaction enthalpies of the resin at 25 to 58℃ were determined as (ΔH=19.7kJ/mol) (for Mo), and (ΔH=4.18kJ/mol) (for W). The composition of extracted complex is MoO2L2 (HL=P507) as determined by the saturation and slope method. Based on the UV spectra and IR speetra, the adsorption mechanism for Mo is proved to be a cation exchange reaction:MoO22++2HL=MoO2L2+2H+. The co-adsorption of W is a hydrogen bond association process.
The adsorption and separation mechanism of Mo and W by Cl-P507 extraction resin have been investigated. The adsorption reaction enthalpies of the resin at 25 to 58℃ were determined as (ΔH=19.7kJ/mol) (for Mo), and (ΔH=4.18kJ/mol) (for W). The composition of extracted complex is MoO2L2 (HL=P507) as determined by the saturation and slope method. Based on the UV spectra and IR speetra, the adsorption mechanism for Mo is proved to be a cation exchange reaction:MoO22++2HL=MoO2L2+2H+. The co-adsorption of W is a hydrogen bond association process.
1992, 9(1): 47-50
Abstract:
LB films of tetraphenylporphin derivatives without hydrophilic substituents have been prepared. The morphorlogy and structure of these films were characterized by transmission electron microscopy, fluorescence lifetime, fluorescence spectra and UV-Vis spectra. It is found that these porphins mainly form aggregates in the ordered films.
LB films of tetraphenylporphin derivatives without hydrophilic substituents have been prepared. The morphorlogy and structure of these films were characterized by transmission electron microscopy, fluorescence lifetime, fluorescence spectra and UV-Vis spectra. It is found that these porphins mainly form aggregates in the ordered films.
1992, 9(1): 51-55
Abstract:
The character and mechanism of Fe2O3-SnO2 composite as a gas sensor were studied. The effects of grain size of iron oxides and the ratio Fe2O3 to SnO2 on gas sensing property were examined.The Fe2O3-SnO2 composite as a gas sensing element has a mixed mechanism of bulkcontrolled type and surface-controlled type. The Fe2O3-SnO2 composite doped with CuO, may be used as C2H2 gas Sensor.
The character and mechanism of Fe2O3-SnO2 composite as a gas sensor were studied. The effects of grain size of iron oxides and the ratio Fe2O3 to SnO2 on gas sensing property were examined.The Fe2O3-SnO2 composite as a gas sensing element has a mixed mechanism of bulkcontrolled type and surface-controlled type. The Fe2O3-SnO2 composite doped with CuO, may be used as C2H2 gas Sensor.
1992, 9(1): 56-60
Abstract:
Heteropoly molybdotungstophosphoric acids (salts) with formula Ln-PMo6W6O40·xH2O (Ln=La, Ce, Pr, Nd) and ZnHP Mo6 W6O40·xH2O were prepared and characterized by elemental analysis, IR, UV spectrometry, and x-ray diffraction.The thermal stabilities of the compounds were as follows:solid acids > rareearth salts > Zn salt.The mechanism of reduction of the heteropolyanion in aqueous solution was proposed.
Heteropoly molybdotungstophosphoric acids (salts) with formula Ln-PMo6W6O40·xH2O (Ln=La, Ce, Pr, Nd) and ZnHP Mo6 W6O40·xH2O were prepared and characterized by elemental analysis, IR, UV spectrometry, and x-ray diffraction.The thermal stabilities of the compounds were as follows:solid acids > rareearth salts > Zn salt.The mechanism of reduction of the heteropolyanion in aqueous solution was proposed.
1992, 9(1): 61-64
Abstract:
The kinetics of extraction of uranium (Ⅵ) from nitric acid solution by tributyl phophate (TBP) in cyclohexane was investigated using single drop and Lewis cell technique.The extraction rate were found to be pseudo-first order with respect to the concentration of uranium (Ⅵ). It was increased with increasing concentration of TBP between 0~0.5 mol/L TBP and had a max/mum at about 4 mol/L nitric acid or nitrate in aqueous solution. The rate was almost independent of the extraction temperature. It is suggested that the extraction rate of uranium(Ⅵ) is controlled by the diffusion of complex UO2(NO2)3·2TBP from interface into organic phase.
The kinetics of extraction of uranium (Ⅵ) from nitric acid solution by tributyl phophate (TBP) in cyclohexane was investigated using single drop and Lewis cell technique.The extraction rate were found to be pseudo-first order with respect to the concentration of uranium (Ⅵ). It was increased with increasing concentration of TBP between 0~0.5 mol/L TBP and had a max/mum at about 4 mol/L nitric acid or nitrate in aqueous solution. The rate was almost independent of the extraction temperature. It is suggested that the extraction rate of uranium(Ⅵ) is controlled by the diffusion of complex UO2(NO2)3·2TBP from interface into organic phase.
1992, 9(1): 65-68
Abstract:
A study of the core-electron x-ray photoelectron spectra showed the presence of satellite structure for the 3d and 4d signals in Ce2O3, CeO2, CeCl3, CeF3. These satellites are discussed in terms of coexcitation of the charge transfer type principally O2p to Ce4f transitions. It is confirmed that in the cerium compounds studied the satellites are due to energy-loss (representing shake-up) rather than energy-gain (shake-down) processes.
A study of the core-electron x-ray photoelectron spectra showed the presence of satellite structure for the 3d and 4d signals in Ce2O3, CeO2, CeCl3, CeF3. These satellites are discussed in terms of coexcitation of the charge transfer type principally O2p to Ce4f transitions. It is confirmed that in the cerium compounds studied the satellites are due to energy-loss (representing shake-up) rather than energy-gain (shake-down) processes.
1992, 9(1): 98-99
Abstract:
The kinetic study on the oxidative coupling of methane over the La-Ba-Na-O catalyst showed that the formation rates of ethane and ethylene were nearly the first order with respect to the partial pressure of methane and zero order to that of oxygen, while the formation rate of carbon dioxide was nearly zero order and the first order with respect to the partial pressures of methane and oxygen, respectively. The reaction mechanism has been discussed on the basis of activation energies.
The kinetic study on the oxidative coupling of methane over the La-Ba-Na-O catalyst showed that the formation rates of ethane and ethylene were nearly the first order with respect to the partial pressure of methane and zero order to that of oxygen, while the formation rate of carbon dioxide was nearly zero order and the first order with respect to the partial pressures of methane and oxygen, respectively. The reaction mechanism has been discussed on the basis of activation energies.
1992, 9(1): 69-71
Abstract:
A novel asymmetric derivative of phthalocyanine copper(Ⅱ), mono-4-(2-methoxyethoxy)-tri-(2,4-di-tert-amylphenoxy) phthalocyanine copper has been prepared and characterized by elementa analysis, IR,1HNMR, ESR and UV. The complex has good filmforming ability. The LB films deposited on gold comb electrode using Z-type technique were rery sensi tire to NH3 vapor.
A novel asymmetric derivative of phthalocyanine copper(Ⅱ), mono-4-(2-methoxyethoxy)-tri-(2,4-di-tert-amylphenoxy) phthalocyanine copper has been prepared and characterized by elementa analysis, IR,1HNMR, ESR and UV. The complex has good filmforming ability. The LB films deposited on gold comb electrode using Z-type technique were rery sensi tire to NH3 vapor.
1992, 9(1): 72-75
Abstract:
In order to find an economical way to prepare sodium nitrate studies have been carried out on the reciprocal system Na+-NH4+-Cl--NO3--H2O.Though the salt-pair of NaNO3-NH4Cl is a stable one,as the phase diagram shows, it is difficult to obtain pure NaNO3 and NH4Cl from it,for the solubilities of NaNO3 and NH4Cl vary with temperature almost in the same extent. A certain sort of optimum conditions has been approached at which the crystal of NaNO3 is more heavy with that of NH4Cl suspending in the solution, thus NaNO3 can be easily separated from NH4Cl.
In order to find an economical way to prepare sodium nitrate studies have been carried out on the reciprocal system Na+-NH4+-Cl--NO3--H2O.Though the salt-pair of NaNO3-NH4Cl is a stable one,as the phase diagram shows, it is difficult to obtain pure NaNO3 and NH4Cl from it,for the solubilities of NaNO3 and NH4Cl vary with temperature almost in the same extent. A certain sort of optimum conditions has been approached at which the crystal of NaNO3 is more heavy with that of NH4Cl suspending in the solution, thus NaNO3 can be easily separated from NH4Cl.
1992, 9(1): 76-78
Abstract:
The structure of two copper phthalocyanines in the process of LB film formation has been studied by transmission electron microscopy. The morphological pictures of the LB films obtained at 5, 25 and 35mN/m were demonstrated. The thickness of monomolecular film depends on the length of substituent and was about of 3~4 nm.The LB films begin to collapse at 25 mN/m, and completely collapse at 35mN/m.
The structure of two copper phthalocyanines in the process of LB film formation has been studied by transmission electron microscopy. The morphological pictures of the LB films obtained at 5, 25 and 35mN/m were demonstrated. The thickness of monomolecular film depends on the length of substituent and was about of 3~4 nm.The LB films begin to collapse at 25 mN/m, and completely collapse at 35mN/m.
1992, 9(1): 79-81
Abstract:
By means of electrochemical method, ellipsometry and AES analysis, the stability of the passive film formed after A.V. modulating passivation and post-treatment was studied. The results show that the defect points can be removed and the surface of the passive film is roughened through A. V. modulating passivation. The adsorption of Mo-Containing ion on the surface of the passive film during post-treatment becomes easier,which further increases the stability of the passive film. A more striking improvement of the stability of the passive film was observed on 302 stainless steel than cn 316 stainless steel.
By means of electrochemical method, ellipsometry and AES analysis, the stability of the passive film formed after A.V. modulating passivation and post-treatment was studied. The results show that the defect points can be removed and the surface of the passive film is roughened through A. V. modulating passivation. The adsorption of Mo-Containing ion on the surface of the passive film during post-treatment becomes easier,which further increases the stability of the passive film. A more striking improvement of the stability of the passive film was observed on 302 stainless steel than cn 316 stainless steel.
1992, 9(1): 82-84
Abstract:
The colored film of CoO-CuO-SiO2 system was prepared by sol-gel method. The effect of several factors, such as concentration of oxides, viscosity of coating solution, heating temperature and heating time on optical transmittance of the film were examined and the compositions for homogeneous glass films were determined. The homogeneous films can be produced only from the system containing more than 50 mol% SiO2. Both Co2+, and Cu2+ ions were shown not to take part in network bonds formation.
The colored film of CoO-CuO-SiO2 system was prepared by sol-gel method. The effect of several factors, such as concentration of oxides, viscosity of coating solution, heating temperature and heating time on optical transmittance of the film were examined and the compositions for homogeneous glass films were determined. The homogeneous films can be produced only from the system containing more than 50 mol% SiO2. Both Co2+, and Cu2+ ions were shown not to take part in network bonds formation.
1992, 9(1): 85-86
Abstract:
Synthesis of two Schiff bases supported on poly (styrene-djvinylbenzene) is described and their adsorption capacities for metal ions were measured. The order of adsorption for P-ensal (Fig.l) is:Cu2+ > Co2+ > Ni2+~Zn2+ > Hg2+ > Pb2+ > Cr2+ > Cd2+;While for P-diensal, the order is:Cu2+~Zn2+ > Co2+ > Ni2+ > Hg2+ > Cr2+~Pb2+ > Cd2+. The adsorption capacities for Fe3+ in ethanol are much larger thanthose in aqueous solution.
Synthesis of two Schiff bases supported on poly (styrene-djvinylbenzene) is described and their adsorption capacities for metal ions were measured. The order of adsorption for P-ensal (Fig.l) is:Cu2+ > Co2+ > Ni2+~Zn2+ > Hg2+ > Pb2+ > Cr2+ > Cd2+;While for P-diensal, the order is:Cu2+~Zn2+ > Co2+ > Ni2+ > Hg2+ > Cr2+~Pb2+ > Cd2+. The adsorption capacities for Fe3+ in ethanol are much larger thanthose in aqueous solution.
1992, 9(1): 87-88
Abstract:
The molecular weight distribution of polyalpha-methylstyrene prepared by anionic polymerization, with n-butyllithium as initiator was investigated. The influences of ether additives, ratios of ether to initiator and polymerization temperature on the molecular weight distribution of polymers were studied.Thereactivity of reactive species and rate of interchange between the reactive species were considered as the main factors effecting the molecular weight distribution of the polymer.With increasing polymerization temperature and by using more strong and concentrated ether additive the molecular weight distribution of the polymer became more narrow.
The molecular weight distribution of polyalpha-methylstyrene prepared by anionic polymerization, with n-butyllithium as initiator was investigated. The influences of ether additives, ratios of ether to initiator and polymerization temperature on the molecular weight distribution of polymers were studied.Thereactivity of reactive species and rate of interchange between the reactive species were considered as the main factors effecting the molecular weight distribution of the polymer.With increasing polymerization temperature and by using more strong and concentrated ether additive the molecular weight distribution of the polymer became more narrow.
1992, 9(1): 89-91
Abstract:
A catalase membrane immobilized on a nylon net was prepared, using freshly synthesized triethylonium tetrafluoroborate as immobilizer. The membrane had an activity of 80unit/cm2,while that immobilized by dimethyl sulfate showed an activity only of 35, 6unit/cm2.The catalase electrode showed linear response within 5,0×10-6~5,0×10-4mol·L-1,with detection lirit of 4,0×10-6mol·L-1 and 95,2% recovery.Its service life is more than 500 times. SO42-, Cl-, NO3-,NH4+,Ac-,glycine,glueose etc. do not interfere with the detection.
A catalase membrane immobilized on a nylon net was prepared, using freshly synthesized triethylonium tetrafluoroborate as immobilizer. The membrane had an activity of 80unit/cm2,while that immobilized by dimethyl sulfate showed an activity only of 35, 6unit/cm2.The catalase electrode showed linear response within 5,0×10-6~5,0×10-4mol·L-1,with detection lirit of 4,0×10-6mol·L-1 and 95,2% recovery.Its service life is more than 500 times. SO42-, Cl-, NO3-,NH4+,Ac-,glycine,glueose etc. do not interfere with the detection.
1992, 9(1): 92-94
Abstract:
High oxygen permeable methylsilicone rubber membranes have been prepared by graft reaction on it with styrene. The results showed that the oxygen permeability of the membrane varies with the dimethylsilicone content in the copolymer. The oxygen permeability coefficient PO2=3.0×10-8cm3cm/cm2·s·cmHg and separation factor αO2/N2=2.25 at 75% content of dimethylsiloxane. The oxygen permeation rate, JO2, of the membrane increased with the increase of molecular weight of the grafted methylsilicone rubber.
High oxygen permeable methylsilicone rubber membranes have been prepared by graft reaction on it with styrene. The results showed that the oxygen permeability of the membrane varies with the dimethylsilicone content in the copolymer. The oxygen permeability coefficient PO2=3.0×10-8cm3cm/cm2·s·cmHg and separation factor αO2/N2=2.25 at 75% content of dimethylsiloxane. The oxygen permeation rate, JO2, of the membrane increased with the increase of molecular weight of the grafted methylsilicone rubber.
1992, 9(1): 95-97
Abstract:
The distribution coefficient of silver in extraction with CL-7402 levextrel in thiosulfate medium was investigated. The adsorption capacity of resin for Ag+ ion was found to be 0,29mmol/g resin, and the complex ratio of resin to Ag(S2O3)23- was 3:1. The nechanism of the adsorption is discussed in terms of IR spectra.
The distribution coefficient of silver in extraction with CL-7402 levextrel in thiosulfate medium was investigated. The adsorption capacity of resin for Ag+ ion was found to be 0,29mmol/g resin, and the complex ratio of resin to Ag(S2O3)23- was 3:1. The nechanism of the adsorption is discussed in terms of IR spectra.
1992, 9(1): 100-102
Abstract:
The differential pulse polarographic behaviour of colchicine have been investigated. A well defined peak was observed in a 0.6% (C4H9)4NCl-B. R. buffer solution (pH 1.81) at potential of -0.90 V(vs Ag/AgCl). An excellent linear relationship existed between the concentration(9.6×10-7~8.6×10-5mol/L) and peak current. This method provides a rapid and simple way to determine colchicine in pharmaceutical preparations and Iphigenia indica Kunth et Benth.
The differential pulse polarographic behaviour of colchicine have been investigated. A well defined peak was observed in a 0.6% (C4H9)4NCl-B. R. buffer solution (pH 1.81) at potential of -0.90 V(vs Ag/AgCl). An excellent linear relationship existed between the concentration(9.6×10-7~8.6×10-5mol/L) and peak current. This method provides a rapid and simple way to determine colchicine in pharmaceutical preparations and Iphigenia indica Kunth et Benth.
1992, 9(1): 103-105
Abstract:
LaF3 and La1-xPbxF3-x (x=0.05~0.15) solid solution materials were prepared and their AC conductivities were measured at frequency of 10kHz Presence of an appropriate amount of PbF2 made the conductivity increase, and the conductivity of La0.95 Pb0.05 F2.95 was about one order of magnitude higher than that of pure LaF3. Four solid galvanic cells made of La0.95 Pb0.05 F2.95 as electrolyte were investigated as potentiometric oxygen sensor. The sensor cell of BiF3(Bi)/La0.95 Pb0.05 F2.95/Pt showed shorter response than the others. The 90% response of the cell took as short as 80s, while oxygen partial pressure changed from 0.21×105Pa to 1.0×105Pa at 150℃.The electrochemical reaction on the sensing electrode was referred to as "two electron reaction".
LaF3 and La1-xPbxF3-x (x=0.05~0.15) solid solution materials were prepared and their AC conductivities were measured at frequency of 10kHz Presence of an appropriate amount of PbF2 made the conductivity increase, and the conductivity of La0.95 Pb0.05 F2.95 was about one order of magnitude higher than that of pure LaF3. Four solid galvanic cells made of La0.95 Pb0.05 F2.95 as electrolyte were investigated as potentiometric oxygen sensor. The sensor cell of BiF3(Bi)/La0.95 Pb0.05 F2.95/Pt showed shorter response than the others. The 90% response of the cell took as short as 80s, while oxygen partial pressure changed from 0.21×105Pa to 1.0×105Pa at 150℃.The electrochemical reaction on the sensing electrode was referred to as "two electron reaction".
1992, 9(1): 106-109
Abstract:
The properties of the coordination compoands of Au(Ⅲ), Au(Ⅰ) and Ag(Ⅰ) with mercapto-acetanil (MAA or HL) are reported.The AuL3 type of the compounds is synthesized for the first time and characterized by elemental analysis, UV, IR and TG-DTA. The ligand (MAA) selectively chelates Au(Ⅲ) from acidic solution or aqua regia containing ions such as Ca, Mg, Cd, Mn, Co, Ni, Cu, Zn and Fe. The formed AuL3. then converts into Au(Ⅰ)L in absolute ethyl alcohol. The gold and silver were recovered through high temperature decomposition of the AuL3 and AgL, respectively. The recovery ratio for gold is over 97%, for silver over 98%. The purity of the obtained gold is 99.89~99.98%. The cost of the method is much lower than that of using zinc pyridinethione as a chelating agent.
The properties of the coordination compoands of Au(Ⅲ), Au(Ⅰ) and Ag(Ⅰ) with mercapto-acetanil (MAA or HL) are reported.The AuL3 type of the compounds is synthesized for the first time and characterized by elemental analysis, UV, IR and TG-DTA. The ligand (MAA) selectively chelates Au(Ⅲ) from acidic solution or aqua regia containing ions such as Ca, Mg, Cd, Mn, Co, Ni, Cu, Zn and Fe. The formed AuL3. then converts into Au(Ⅰ)L in absolute ethyl alcohol. The gold and silver were recovered through high temperature decomposition of the AuL3 and AgL, respectively. The recovery ratio for gold is over 97%, for silver over 98%. The purity of the obtained gold is 99.89~99.98%. The cost of the method is much lower than that of using zinc pyridinethione as a chelating agent.
1992, 9(1): 110-114
Abstract:
The mass spectra of phosphodiamidoates have been studied using positive ion FABMS and negative ion FABMS. Attention was focused on the distinction between positive ion FABMS and negative ion FABMS. The ion fragmentation mechanism is confirmed by using linked scanning techniques.
The mass spectra of phosphodiamidoates have been studied using positive ion FABMS and negative ion FABMS. Attention was focused on the distinction between positive ion FABMS and negative ion FABMS. The ion fragmentation mechanism is confirmed by using linked scanning techniques.
1992, 9(1): 115-117
Abstract:
meso-Tetraphenyl-porphyrin (H2TPP) was first used as an indicator of acid sensitive film composed of vinylidene chloridemethyl acrylate copolymer.The color of H2TPP-acid sensitive film changes from purplish red to green upon exposure to 254 nm light due to the formation of HCl salt of H2TTP. HCl is released from acid sensthive film up on UV irradiation. H2TPP-acid sensitive film showed a better image stability than that with dimethyl yellow because a shang polar compound is formed from IR spectra results.
meso-Tetraphenyl-porphyrin (H2TPP) was first used as an indicator of acid sensitive film composed of vinylidene chloridemethyl acrylate copolymer.The color of H2TPP-acid sensitive film changes from purplish red to green upon exposure to 254 nm light due to the formation of HCl salt of H2TTP. HCl is released from acid sensthive film up on UV irradiation. H2TPP-acid sensitive film showed a better image stability than that with dimethyl yellow because a shang polar compound is formed from IR spectra results.
