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1990 Volume 7 Issue 3
1990, 7(3): 1-5
Abstract:
The kinetics of extraction erhium(Ⅲ)from sulphurib acid solutions with HEHl[EHP] in n-heptane has been investigated. The effects of the concentrations of Er3+,H+,SO42-,and HEH[EHP] on the extraction rate for Er(Ⅲ) have been observed. It is found that the rate of forward extraction reaction is proportional to[Er3+],[H+]-2.25,[SO42-]0.26 and [H2A2](o)1.69,white the rate of backward extraction reaction is proportional to [Er(Ⅲ)](o),[H+]1.05 and [H2A2](o)-1.08.The rate-determining step is suggested to be the chemical reaction of ErA2 with HA at the interface for forward extraction and H~+ with ErA3(o) at the inter-face for backward extraction.
The kinetics of extraction erhium(Ⅲ)from sulphurib acid solutions with HEHl[EHP] in n-heptane has been investigated. The effects of the concentrations of Er3+,H+,SO42-,and HEH[EHP] on the extraction rate for Er(Ⅲ) have been observed. It is found that the rate of forward extraction reaction is proportional to[Er3+],[H+]-2.25,[SO42-]0.26 and [H2A2](o)1.69,white the rate of backward extraction reaction is proportional to [Er(Ⅲ)](o),[H+]1.05 and [H2A2](o)-1.08.The rate-determining step is suggested to be the chemical reaction of ErA2 with HA at the interface for forward extraction and H~+ with ErA3(o) at the inter-face for backward extraction.
1990, 7(3): 6-9
Abstract:
Six of two types ferrocenylpolythia crown ethers(1-6) were prepared by reacting 1,1'-bis(hydroxymethyl) ferrocene or ferrocenccarboxyaldehyde with α,ω-dimercaptan compounds in good yield.A serics of Ag-ion-selective electrodes based on the crown ethers (2-6) as elec-troactive material were prepared. The electrode with 4 was found to have the best properties.It shows linear response of 1×10-1-3×10-5mol/L AgNO3 and potentiometric selectivity co-efficients of 10-3 and 10-4-10-5 for cations of Ⅰ and Ⅱ valency respeetively. The selecti-vities of the electrodes for Na+,Hg2+, Mg2+ were 44-682 times better than other crown ether electrodes reported in literature.
Six of two types ferrocenylpolythia crown ethers(1-6) were prepared by reacting 1,1'-bis(hydroxymethyl) ferrocene or ferrocenccarboxyaldehyde with α,ω-dimercaptan compounds in good yield.A serics of Ag-ion-selective electrodes based on the crown ethers (2-6) as elec-troactive material were prepared. The electrode with 4 was found to have the best properties.It shows linear response of 1×10-1-3×10-5mol/L AgNO3 and potentiometric selectivity co-efficients of 10-3 and 10-4-10-5 for cations of Ⅰ and Ⅱ valency respeetively. The selecti-vities of the electrodes for Na+,Hg2+, Mg2+ were 44-682 times better than other crown ether electrodes reported in literature.
1990, 7(3): 10-13
Abstract:
The stability constants for mixed ligand complexes of rare earth with nitrilotriacetic acid as primary ligand and amino acid as secondary ligand have been determined by potentiometric titration at 25℃ and an ionic strength of 0.15mol/dm3(NaCl). A discussion on the relation-ship between the stability constants for the mixed ligand complexes and the atomic number of rare earth has been made. It was found that the position of Y in the ternary system shifted to the vicinity of neodymium.
The stability constants for mixed ligand complexes of rare earth with nitrilotriacetic acid as primary ligand and amino acid as secondary ligand have been determined by potentiometric titration at 25℃ and an ionic strength of 0.15mol/dm3(NaCl). A discussion on the relation-ship between the stability constants for the mixed ligand complexes and the atomic number of rare earth has been made. It was found that the position of Y in the ternary system shifted to the vicinity of neodymium.
1990, 7(3): 14-18
Abstract:
A synergetic extraction-eluting resiri(Levextrel) containing petroleum sulfoxide (PSO) and N,N-di (1-methylheptyl) acetamide (N503) has been prepared. The resin has a saturated absorption capacity of 148mg Au per gram dry resin. The absorption performance of the ex-traction-eluting resin has been investigated. The results of coluinn separation experiments showed that the gold and palladium retained on column could be effectively eluted with 0.5% thiourea solution.
A synergetic extraction-eluting resiri(Levextrel) containing petroleum sulfoxide (PSO) and N,N-di (1-methylheptyl) acetamide (N503) has been prepared. The resin has a saturated absorption capacity of 148mg Au per gram dry resin. The absorption performance of the ex-traction-eluting resin has been investigated. The results of coluinn separation experiments showed that the gold and palladium retained on column could be effectively eluted with 0.5% thiourea solution.
1990, 7(3): 19-23
Abstract:
The electrochemical oxidation of phenylenediamines with a following irreversibie deami-nation reaction was studied by cyclovoltammetry. Within the pH studied, there is only one oxidation Wave for N,N-diethylphenylenediamine (1a), but two oxidation waves for N,N,N,N-tetrathlphenylenediamine(2a).In acidic media, the electrochemical oxidation of N,N-diethylaminophenol(3a) proceeds via two-electron transfer, but at higher pH two single electron transfer are involved. The rate constant of the deamination reaction kf was deter-mined as a function of pH, the mechanism of deamination was discussed.
The electrochemical oxidation of phenylenediamines with a following irreversibie deami-nation reaction was studied by cyclovoltammetry. Within the pH studied, there is only one oxidation Wave for N,N-diethylphenylenediamine (1a), but two oxidation waves for N,N,N,N-tetrathlphenylenediamine(2a).In acidic media, the electrochemical oxidation of N,N-diethylaminophenol(3a) proceeds via two-electron transfer, but at higher pH two single electron transfer are involved. The rate constant of the deamination reaction kf was deter-mined as a function of pH, the mechanism of deamination was discussed.
1990, 7(3): 24-28
Abstract:
Oxo-bridged tri-and Tetranuclear manganese complexes:Mn3O(salala-β)3·3H2O and Mn4O2 (salala-β)3 (ClO4)2·8H2O, where salala-β2- is the dianion of tridentate Shiff base sali-cylidene-β-alanine, have been synthesized and characterized by elemental analyses,valence determination, electronic conductivity,magnetic susceptibility, thermogravimetric analyses,infrared and electronic spectra etc. The possible structures of the complexes are suggested.
Oxo-bridged tri-and Tetranuclear manganese complexes:Mn3O(salala-β)3·3H2O and Mn4O2 (salala-β)3 (ClO4)2·8H2O, where salala-β2- is the dianion of tridentate Shiff base sali-cylidene-β-alanine, have been synthesized and characterized by elemental analyses,valence determination, electronic conductivity,magnetic susceptibility, thermogravimetric analyses,infrared and electronic spectra etc. The possible structures of the complexes are suggested.
1990, 7(3): 29-32
Abstract:
The effect of a novel latent accelerator, neodymium acetylacetonate(AD), on the proper-ties of cured resin for bisphenol A epoxy resin(E-44)/Tung oil acid anhydride(TOA) system is reported in this paper. Presence of AD decreased the gel time at 150℃ and increased the activation energy with increasing amount of AD. The E-44/TOA/AD system displayed bet-ter storage stability at 40℃ than the control. The incorporation of AD into the epoxy resin caused an increase in the Tg values and depressed the dielectric loss Tanδ at 130℃.155℃ of Nd ion-containing epoxy. The mechan-ical properties were raised as compared with the control. It might be due to the special electron structure of rare-earth elements which makes the epoxy system having higher Tg owing to the higher crosslink density or more homogenoous network structure.
The effect of a novel latent accelerator, neodymium acetylacetonate(AD), on the proper-ties of cured resin for bisphenol A epoxy resin(E-44)/Tung oil acid anhydride(TOA) system is reported in this paper. Presence of AD decreased the gel time at 150℃ and increased the activation energy with increasing amount of AD. The E-44/TOA/AD system displayed bet-ter storage stability at 40℃ than the control. The incorporation of AD into the epoxy resin caused an increase in the Tg values and depressed the dielectric loss Tanδ at 130℃.155℃ of Nd ion-containing epoxy. The mechan-ical properties were raised as compared with the control. It might be due to the special electron structure of rare-earth elements which makes the epoxy system having higher Tg owing to the higher crosslink density or more homogenoous network structure.
1990, 7(3): 33-38
Abstract:
A study of the effect of thermal treatment on epitaxial crystallization in HDPE/iPP blends was carried out by means of TEM and specimen tilt technique of electron microscopy. When the solution-cast films of HDPE/iPP blends were heated to above the melting point of HDPE(145℃) for about 30 min., and subsequently cooled to room temperature, the size of the recrystallized lamellae of HDPE increased in both regions of the cross-hatched and single-crystal-type structure of iPP. However, the epitaxial and structural relationships between HDPE and iPP remained unchanged. Under the heat treatment of higher temperature (194℃,20 min.), the morphologies and structures of recrystallized HDPE and iPP in the blend were similar to that of the blend heat-treated at lower temperature(145℃).
A study of the effect of thermal treatment on epitaxial crystallization in HDPE/iPP blends was carried out by means of TEM and specimen tilt technique of electron microscopy. When the solution-cast films of HDPE/iPP blends were heated to above the melting point of HDPE(145℃) for about 30 min., and subsequently cooled to room temperature, the size of the recrystallized lamellae of HDPE increased in both regions of the cross-hatched and single-crystal-type structure of iPP. However, the epitaxial and structural relationships between HDPE and iPP remained unchanged. Under the heat treatment of higher temperature (194℃,20 min.), the morphologies and structures of recrystallized HDPE and iPP in the blend were similar to that of the blend heat-treated at lower temperature(145℃).
1990, 7(3): 39-42
Abstract:
A structure model of cryolite-alumina melt was calculated with Monte Carlo methode computer simulation. The local structure and radial distribution functions of the molten salt were computed at 1283 K. In the melt, Al3+ tended to have preferential even coordination number 3,1 with F-. It has been found that there exist complex ions such as AlF4-,AlOF32-, AlOF2-, AlF52-, AlF3. There also exist oxygenbridge[AlF3-O-AlF3]2- and flo-urien bridge[F3Al-F-AlF3]- ionic clusters due to mutual reactions between various species in the molten cryolite-alumina.
A structure model of cryolite-alumina melt was calculated with Monte Carlo methode computer simulation. The local structure and radial distribution functions of the molten salt were computed at 1283 K. In the melt, Al3+ tended to have preferential even coordination number 3,1 with F-. It has been found that there exist complex ions such as AlF4-,AlOF32-, AlOF2-, AlF52-, AlF3. There also exist oxygenbridge[AlF3-O-AlF3]2- and flo-urien bridge[F3Al-F-AlF3]- ionic clusters due to mutual reactions between various species in the molten cryolite-alumina.
1990, 7(3): 43-46
Abstract:
The structure and properties of YBa2Cu3O7-y:Agx superconductor have been studied. The system showed lower normal state resistivity and better ductility.XRD analysis showed that the system remains orthorhombic structure when the content of silver x<2.0.Increase of Ag did not change the a and b axes but substantially expanded in the c axis about 0.33% at x=1.5. This indicates that the silver has partly enter into the lattice cell of 123 phase.YBa2Cu3O7-y:Agx exhibits fine grains and net framework improving the weak-link in it in SEM. The critical current density is enhanced from 50A/cm2 to 572A/cm2.
The structure and properties of YBa2Cu3O7-y:Agx superconductor have been studied. The system showed lower normal state resistivity and better ductility.XRD analysis showed that the system remains orthorhombic structure when the content of silver x<2.0.Increase of Ag did not change the a and b axes but substantially expanded in the c axis about 0.33% at x=1.5. This indicates that the silver has partly enter into the lattice cell of 123 phase.YBa2Cu3O7-y:Agx exhibits fine grains and net framework improving the weak-link in it in SEM. The critical current density is enhanced from 50A/cm2 to 572A/cm2.
1990, 7(3): 47-50
Abstract:
The structure of poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP) blends of va-rious compositions has been studied by wide angle X-ray diffractometry before and after heat treatment. The plane (101) was observed only at 2θ=11.4°before heat treatment, but over four planes were found after heat treatment. The degree of crystallinity and crystal-lite size were decreased with increasing the PVP content in blends. Applying Hosemann's concept of paracrystallinity as well as Cauchy and Gaussian function approximations,parameters of the crystallite size, strain and the second kind lattice distortion have been calculated.
The structure of poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP) blends of va-rious compositions has been studied by wide angle X-ray diffractometry before and after heat treatment. The plane (101) was observed only at 2θ=11.4°before heat treatment, but over four planes were found after heat treatment. The degree of crystallinity and crystal-lite size were decreased with increasing the PVP content in blends. Applying Hosemann's concept of paracrystallinity as well as Cauchy and Gaussian function approximations,parameters of the crystallite size, strain and the second kind lattice distortion have been calculated.
1990, 7(3): 51-53
Abstract:
The effects of polyisobutylene oligomer (PIB) on the mechanical, dynamic mechanical,damping properties and morphology of the polymer blend based on polyvinylchloride(PVC)-PIB were studied. The influnces of some additives on the damping property of the blend have been examined. The results sbow that petroleum resin is a good additive for PVC-PIB blend,improving the compatibility of the blend.
The effects of polyisobutylene oligomer (PIB) on the mechanical, dynamic mechanical,damping properties and morphology of the polymer blend based on polyvinylchloride(PVC)-PIB were studied. The influnces of some additives on the damping property of the blend have been examined. The results sbow that petroleum resin is a good additive for PVC-PIB blend,improving the compatibility of the blend.
1990, 7(3): 54-56
Abstract:
Diphenyliodonium fluoroborate(Ph2I+BF4-) is found to be an effective photoinitiator for the cationic polymerization of epoxypolysilicone, and benzoin alkyl ethers can promote this photoinitiated polymerization. The order of promotion was:benzoin dimethyl ether > benzoin isopropyl ether > benzoin methyl ether.
Diphenyliodonium fluoroborate(Ph2I+BF4-) is found to be an effective photoinitiator for the cationic polymerization of epoxypolysilicone, and benzoin alkyl ethers can promote this photoinitiated polymerization. The order of promotion was:benzoin dimethyl ether > benzoin isopropyl ether > benzoin methyl ether.
1990, 7(3): 57-59
Abstract:
The sol of γ-irradiated polystyrene has been investigated by using SEC-LALLS combination technology. The changes of the sol properties after and before gel point for polystyrene were observed. The results show that in the early stage of irradiation mainly the molecules of higher mloecular weight take part in crosslinking reaction. The concen-tration of low moleculat weight fractions Changes little before the gel point,but it changes greatly near and after the gel point.
The sol of γ-irradiated polystyrene has been investigated by using SEC-LALLS combination technology. The changes of the sol properties after and before gel point for polystyrene were observed. The results show that in the early stage of irradiation mainly the molecules of higher mloecular weight take part in crosslinking reaction. The concen-tration of low moleculat weight fractions Changes little before the gel point,but it changes greatly near and after the gel point.
1990, 7(3): 60-63
Abstract:
Crystalline polymorphs from the glass state of poly (vinylidene fluoride)(PVF2) induced by high-rate heating have been studied by FTIR and TEM. The glass state PVF2 sample was obtained by ultraquenching the thin films into liquid nitrogen. Three kinds of poly-morphs were formed when the sample was heated very quickly to higher temperatures with subsequent isothermal crystallization. High-rate warming the glass to the temperatures below 30℃ results in formation of β phase microcrystals. When the glass is heated very quickly to 150℃ predominantly the α phase lamellae or spherulites were obtained, while at temp-eratures of 40-70℃,the β phase and α phase coexisted. If the temperature of high-rate heating was upto 165℃, the perfect spherulites of γ phase PVF2 were observed.
Crystalline polymorphs from the glass state of poly (vinylidene fluoride)(PVF2) induced by high-rate heating have been studied by FTIR and TEM. The glass state PVF2 sample was obtained by ultraquenching the thin films into liquid nitrogen. Three kinds of poly-morphs were formed when the sample was heated very quickly to higher temperatures with subsequent isothermal crystallization. High-rate warming the glass to the temperatures below 30℃ results in formation of β phase microcrystals. When the glass is heated very quickly to 150℃ predominantly the α phase lamellae or spherulites were obtained, while at temp-eratures of 40-70℃,the β phase and α phase coexisted. If the temperature of high-rate heating was upto 165℃, the perfect spherulites of γ phase PVF2 were observed.
1990, 7(3): 64-65
Abstract:
A new type of quaternary ammonium compounds is reported. It is found to posses a higher phase transfer catalytic behavior than the commonly used quaternaty ammonium compounds and dibenzo-18-crown-6 for dichlorocarbene formation.
A new type of quaternary ammonium compounds is reported. It is found to posses a higher phase transfer catalytic behavior than the commonly used quaternaty ammonium compounds and dibenzo-18-crown-6 for dichlorocarbene formation.
1990, 7(3): 66-68
Abstract:
The influence of the structure of organoaluminum compounds on the propylene oligome-rization in the catalyst system containing nickel acetylacetate has been studied. It was found that the structure of the substituted,group in organcaluminum compounds showed a re-markable influence on the activity of the catalyst.
The influence of the structure of organoaluminum compounds on the propylene oligome-rization in the catalyst system containing nickel acetylacetate has been studied. It was found that the structure of the substituted,group in organcaluminum compounds showed a re-markable influence on the activity of the catalyst.
1990, 7(3): 69-71
Abstract:
A series of polystyrene supported phosphonium salts with degree of functionality of 0.36~0.62mmol/g were prepared by reacting bromoalkylated resins with tributylphosphine. The activity of these catalysts were examined by nucleophilic substitution reactions, such as cyanidation, iodization, and sultide formation. They showed satisfactory catalytic efficiency.
A series of polystyrene supported phosphonium salts with degree of functionality of 0.36~0.62mmol/g were prepared by reacting bromoalkylated resins with tributylphosphine. The activity of these catalysts were examined by nucleophilic substitution reactions, such as cyanidation, iodization, and sultide formation. They showed satisfactory catalytic efficiency.
1990, 7(3): 72-75
Abstract:
China-made poly (phenylene ether ketone) (PEK-C) is an amorphous high-performance thermoplast with glass transition temperature 231℃, and tensile modulus 2.43GPa, tensile strength 101 MPa and elongation at break 6.1% at room temperature. Single edge notched specimens were used to measure fracture toughness K1c and critical strain energy release rate G1c in terms of linear elastic theory as well as critical J-integral value J1c in terms of elastic-plastic theory. The values of K1c, G1c and J1c for PEK-C are, respectively,2.34 MPa√m, 2.1 kJ/m2 and 2.76 kJ/m2 compared wih K1c 2.86 MPa√m and G1c 2.07kJ/m2 for PEEK of ICI and K1c 1.96 MPa√m and G1c 1 kJ/m2 for PEKK of DuPont.
China-made poly (phenylene ether ketone) (PEK-C) is an amorphous high-performance thermoplast with glass transition temperature 231℃, and tensile modulus 2.43GPa, tensile strength 101 MPa and elongation at break 6.1% at room temperature. Single edge notched specimens were used to measure fracture toughness K1c and critical strain energy release rate G1c in terms of linear elastic theory as well as critical J-integral value J1c in terms of elastic-plastic theory. The values of K1c, G1c and J1c for PEK-C are, respectively,2.34 MPa√m, 2.1 kJ/m2 and 2.76 kJ/m2 compared wih K1c 2.86 MPa√m and G1c 2.07kJ/m2 for PEEK of ICI and K1c 1.96 MPa√m and G1c 1 kJ/m2 for PEKK of DuPont.
1990, 7(3): 76-78
Abstract:
The hydrolysis of CH2=CHSi(OEt)3 has been studied. by 1HNMR measurement. The reaction was considered to be catalyzed by both H+ and OH-; and the stronger the acidity or the basity, the more rapid the reaction. The reactant also influenced the hydrolysis reaction, especially in the initial period. Some information about the polymerization of the hydrolysis product of silane were obtained.
The hydrolysis of CH2=CHSi(OEt)3 has been studied. by 1HNMR measurement. The reaction was considered to be catalyzed by both H+ and OH-; and the stronger the acidity or the basity, the more rapid the reaction. The reactant also influenced the hydrolysis reaction, especially in the initial period. Some information about the polymerization of the hydrolysis product of silane were obtained.
1990, 7(3): 79-81
Abstract:
A chiral bidentate phosphine, 2, 3-isopropyldene-1, 4-bis((diphenylphosphino) amino) bu-tane derived from L-(+)-tartaric acid has been obtained. The rhodium (Ⅰ)-complex of this ligand with (Rh(COD) ClO4) in the asymmetric hydrogenation of three derivatives of α-aceta-midoacrylic acid gives 10.4-25.6% optical yield.
A chiral bidentate phosphine, 2, 3-isopropyldene-1, 4-bis((diphenylphosphino) amino) bu-tane derived from L-(+)-tartaric acid has been obtained. The rhodium (Ⅰ)-complex of this ligand with (Rh(COD) ClO4) in the asymmetric hydrogenation of three derivatives of α-aceta-midoacrylic acid gives 10.4-25.6% optical yield.
1990, 7(3): 82-84
Abstract:
Synthetic food colourants-tartrazine and ponceau-4R are found to be adsorbed strongly on a hanging mercury drop electrode and can thus be determined by linear sweep adsorption voltammetry.The peaks of derivative waves can be produced at -0.74V and -0.82V respec-tively for tortrazine and ponceau-4R in a buffer solution of disodium hydrogen phosphate,pH-8.8. The determination limit is of 3.0×10-9mol/L and 2.0×10-9mol/L respectively.The method has been used to the determination of the colourant in food.
Synthetic food colourants-tartrazine and ponceau-4R are found to be adsorbed strongly on a hanging mercury drop electrode and can thus be determined by linear sweep adsorption voltammetry.The peaks of derivative waves can be produced at -0.74V and -0.82V respec-tively for tortrazine and ponceau-4R in a buffer solution of disodium hydrogen phosphate,pH-8.8. The determination limit is of 3.0×10-9mol/L and 2.0×10-9mol/L respectively.The method has been used to the determination of the colourant in food.
1990, 7(3): 85-88
Abstract:
A homogeneous rare earth catalyst comprising neodymium octonate, diisobutylaluminum hydride and dichlorodiphenylsilane[Nd(Oct)3-HAl(i-Bu)2-φ2SiCl2] for stereospecific polymeri-zation of butadiene was selected to study the action of the third component in the homoge-neous system. Investigation on reactions between Nd(oct)3, HAl(i-Bu)2 and φ2SiCl2 by means of NMR(1H and 13C spectra) showed that the φ2SiCl2,unlike alkyl aluminum chloride,does not react directly with Nd-salt, suepplying the chlorine atom, it reacts first with HAl(i-Bu)2, giving φ2SiH2 and Al(i-Bu)2Cl, and the latter affords the Nd-salt chlorine atom necessary for forming an active catalyst.Some experimental facts found in polymeriza-tion of butadiene using the catalyst were explained by the reaction path mentioned above.
A homogeneous rare earth catalyst comprising neodymium octonate, diisobutylaluminum hydride and dichlorodiphenylsilane[Nd(Oct)3-HAl(i-Bu)2-φ2SiCl2] for stereospecific polymeri-zation of butadiene was selected to study the action of the third component in the homoge-neous system. Investigation on reactions between Nd(oct)3, HAl(i-Bu)2 and φ2SiCl2 by means of NMR(1H and 13C spectra) showed that the φ2SiCl2,unlike alkyl aluminum chloride,does not react directly with Nd-salt, suepplying the chlorine atom, it reacts first with HAl(i-Bu)2, giving φ2SiH2 and Al(i-Bu)2Cl, and the latter affords the Nd-salt chlorine atom necessary for forming an active catalyst.Some experimental facts found in polymeriza-tion of butadiene using the catalyst were explained by the reaction path mentioned above.
1990, 7(3): 89-92
Abstract:
15α,β-unsaturated ketones and 12 2,4-alkadienones were prepared by the Claisen Schmidt condensation reaction catalyzed by bis(p-methoxyphenyl) telluroxide (BMPTO). All the products are E-isomeric as confirmed by their m.p. and IR spectra determinations.
15α,β-unsaturated ketones and 12 2,4-alkadienones were prepared by the Claisen Schmidt condensation reaction catalyzed by bis(p-methoxyphenyl) telluroxide (BMPTO). All the products are E-isomeric as confirmed by their m.p. and IR spectra determinations.
