Login In
1985 Volume 2 Issue 1
1985, 2(1): 1-7
Abstract:
All dimethylsulphoxide complexes of rare earth nitrates (except Pm) were synthesized. Large dimensional crystals of La or Nd (60×28×25mm or 80×28×28mm respectively)were grown. The composition of complexes with fromLa to Gd is RE(NO3)3·4DMSO and those with from Tb to Lu (including Y)is RE(NO3)3·3DMSO. Because of steric hindrance causing by lanthanide con-traction, the number of the bound DMSO is decreased from 4 to 3 and the coordination number is decreased from 10 to 9. Comparing the absorption spectra of Nd3+ ion in aqueous solution with those in DMSO solution,red shift of the spectral bands of Nd3+ ion in DM-SO solution has been observed, this implies that in the DMSO solution there exists a certain degree of covalency in the RE-O bond. When the crystals are thermal decomposed in air at 850℃, the composition of the thermal decomposed products of the trivalent rare earth ions becomes RE2O2SO4(RE=Nd3+, Eu3+,Y3+). The magnetic susceptibilities Xg of all dimethylsulphoxide complexes of rare earth nitrates have been determined. As the atomic number (Z) of rare earths increases they change periodically and there appear two maxima in the plot of Xg vs. Z. The absorption, excitation and fluorescence spectra of Pr (NO3)3·4DMSO and Tb(NO3)33DMSO were determined.
All dimethylsulphoxide complexes of rare earth nitrates (except Pm) were synthesized. Large dimensional crystals of La or Nd (60×28×25mm or 80×28×28mm respectively)were grown. The composition of complexes with fromLa to Gd is RE(NO3)3·4DMSO and those with from Tb to Lu (including Y)is RE(NO3)3·3DMSO. Because of steric hindrance causing by lanthanide con-traction, the number of the bound DMSO is decreased from 4 to 3 and the coordination number is decreased from 10 to 9. Comparing the absorption spectra of Nd3+ ion in aqueous solution with those in DMSO solution,red shift of the spectral bands of Nd3+ ion in DM-SO solution has been observed, this implies that in the DMSO solution there exists a certain degree of covalency in the RE-O bond. When the crystals are thermal decomposed in air at 850℃, the composition of the thermal decomposed products of the trivalent rare earth ions becomes RE2O2SO4(RE=Nd3+, Eu3+,Y3+). The magnetic susceptibilities Xg of all dimethylsulphoxide complexes of rare earth nitrates have been determined. As the atomic number (Z) of rare earths increases they change periodically and there appear two maxima in the plot of Xg vs. Z. The absorption, excitation and fluorescence spectra of Pr (NO3)3·4DMSO and Tb(NO3)33DMSO were determined.
1985, 2(1): 8-14
Abstract:
Catalytic characteristics of four types of triphase catalysts: polymeric crown ethers (A), polymeric azacrown ethers(B),modified phenol formalde hyderesin containing benzo-15-crown-5 (C) and crosslinked acyclic polypode polyethers (D) in the cyano- and iodo-substitutions and the addition reaction of dichlorocarbene to styrene were studied. The catalytic activity of polymers was found in following sequence: (B) (with>NR in the ring) >(A) >(C) >(D) >(B) (with>NH in the ring). The best one among the polymeric catalysts studied is that containing azacrown ether with N-alkyl group.
Catalytic characteristics of four types of triphase catalysts: polymeric crown ethers (A), polymeric azacrown ethers(B),modified phenol formalde hyderesin containing benzo-15-crown-5 (C) and crosslinked acyclic polypode polyethers (D) in the cyano- and iodo-substitutions and the addition reaction of dichlorocarbene to styrene were studied. The catalytic activity of polymers was found in following sequence: (B) (with>NR in the ring) >(A) >(C) >(D) >(B) (with>NH in the ring). The best one among the polymeric catalysts studied is that containing azacrown ether with N-alkyl group.
1985, 2(1): 15-18
Abstract:
Based on conformation analysis it has been found that the correlations among glassy transition temperature, Tg, cross-sectional area per chain, A, and steric factor of internal rotation, σ, for fluoropolymers are similar to those for other polymers. The equation,Tg=973(σ-1.44), has been found for the estimation of the value of the steric foctor of fluoropolymer chains. The fact that at the same values of steric factor the glassy transition temperatures of fluoropolymers are higher than those of other polymers is attributed to the bensely packed chains of fluoropolymers.
Based on conformation analysis it has been found that the correlations among glassy transition temperature, Tg, cross-sectional area per chain, A, and steric factor of internal rotation, σ, for fluoropolymers are similar to those for other polymers. The equation,Tg=973(σ-1.44), has been found for the estimation of the value of the steric foctor of fluoropolymer chains. The fact that at the same values of steric factor the glassy transition temperatures of fluoropolymers are higher than those of other polymers is attributed to the bensely packed chains of fluoropolymers.
1985, 2(1): 19-23
Abstract:
The electroreduction of alizarin green has been studied by polarography and cyclic voltammetry. One to four waves of alizarin green appear depending on pH in Britton-Robinson buffer solution. Wave Ⅰ and Wave Ⅰ Vare of adsorption character.The sum of wave Ⅰ and wave Ⅱ is related to the electroreduction of alizarin green from its oxidized form to an intermediate, while wave Ⅲ is due to the further reduction. An electroreduction mechanism of alizarin green involving disproportion reaction has been proposed.
The electroreduction of alizarin green has been studied by polarography and cyclic voltammetry. One to four waves of alizarin green appear depending on pH in Britton-Robinson buffer solution. Wave Ⅰ and Wave Ⅰ Vare of adsorption character.The sum of wave Ⅰ and wave Ⅱ is related to the electroreduction of alizarin green from its oxidized form to an intermediate, while wave Ⅲ is due to the further reduction. An electroreduction mechanism of alizarin green involving disproportion reaction has been proposed.
1985, 2(1): 24-28
Abstract:
In this paper, by using the Judd-Ofelt theory, the oscillator strength parameters Ωλ and the oscillator strength were calculated. They agree with the experimental values. The reduce matrix elements and the radiative transition probabilities of 4G5/2-6HJ transitions were calculated as well.
In this paper, by using the Judd-Ofelt theory, the oscillator strength parameters Ωλ and the oscillator strength were calculated. They agree with the experimental values. The reduce matrix elements and the radiative transition probabilities of 4G5/2-6HJ transitions were calculated as well.
1985, 2(1): 29-33
Abstract:
Polystyrene,cross-linked with 5-7% of divinylbenzene,is combined withTi Cl4 in CS2 to form a stable complex containing 4.5% of chlorine. The TiCl4 complexed in the polymer is resistant to water and can store in air at least for one year. The Lewis acid complex catalyst can be used to catalyze the conversion of aromatic aldehydes,carboxylic acids,ketones and some alcohols into corresponding acetals,esters,ketals and ethers in hish yield. The complex is also effective for the Friedel-Crafts alkylation reaction. For these reactions the title catalyst can be used repeatedly 4-5 times.
Polystyrene,cross-linked with 5-7% of divinylbenzene,is combined withTi Cl4 in CS2 to form a stable complex containing 4.5% of chlorine. The TiCl4 complexed in the polymer is resistant to water and can store in air at least for one year. The Lewis acid complex catalyst can be used to catalyze the conversion of aromatic aldehydes,carboxylic acids,ketones and some alcohols into corresponding acetals,esters,ketals and ethers in hish yield. The complex is also effective for the Friedel-Crafts alkylation reaction. For these reactions the title catalyst can be used repeatedly 4-5 times.
1985, 2(1): 34-38
Abstract:
Various kinds of metal oxides which were intentionally dispersed on glassy carbon electrode surfaces reveal catalytic activities for the oxidation of ascorbic acid and oxalic acid. The highest catalytic activities among many metal oxides dispersed on glassy carbon electodes were shown at ZrO2,CeO2, Co2O3,Cr2O3, SnO2 and α-Al2O3. The electrocatalytic behaviours in relation with the properties of metal oxides and the mechanism of oxidation process was investigated using chronoamperometry, chronopotentiometry and cyclic voltametry.
Various kinds of metal oxides which were intentionally dispersed on glassy carbon electrode surfaces reveal catalytic activities for the oxidation of ascorbic acid and oxalic acid. The highest catalytic activities among many metal oxides dispersed on glassy carbon electodes were shown at ZrO2,CeO2, Co2O3,Cr2O3, SnO2 and α-Al2O3. The electrocatalytic behaviours in relation with the properties of metal oxides and the mechanism of oxidation process was investigated using chronoamperometry, chronopotentiometry and cyclic voltametry.
1985, 2(1): 39-42
Abstract:
The kinetics of O2 anodic evolution was studied in alk.solution. The results show that the values of ∂ψ/∂lgi egual 39 mV and 120 mV at low andhigh currents, respectively, and that of ∂ψ/∂lgaOH- egual -2×39 mV at low currents and-120 mV at high currents. The kinetic data obtained show that the rate determining step of the anodic evolution of oxygen on Pt and mild steel electrode is MOHad+OH-→MOad+H2O+e The influences of Li+, Na+, K+, CNS- and Cl- ions on the reaction ratewere discussed as well.
The kinetics of O2 anodic evolution was studied in alk.solution. The results show that the values of ∂ψ/∂lgi egual 39 mV and 120 mV at low andhigh currents, respectively, and that of ∂ψ/∂lgaOH- egual -2×39 mV at low currents and-120 mV at high currents. The kinetic data obtained show that the rate determining step of the anodic evolution of oxygen on Pt and mild steel electrode is MOHad+OH-→MOad+H2O+e The influences of Li+, Na+, K+, CNS- and Cl- ions on the reaction ratewere discussed as well.
1985, 2(1): 43-47
Abstract:
A red-violet ternary complex of scandium with GCR and CTMAB is formed in a weak acid solution. The maximum absorption. of the ternary complex is at 540nm with apparent molar absorption coefficient of 4.14×104. The composition of ternary complex is found as: Sc:GCR:CTMAB=1:2:2. For the Sc dertermination the interfreences of the diverse ions was reduced by masking with a mixture of acetylaceton and phenanthroline.The method has been used satisfactorily to determine small amount of Sc in the synthetic mixture of rare earths.
A red-violet ternary complex of scandium with GCR and CTMAB is formed in a weak acid solution. The maximum absorption. of the ternary complex is at 540nm with apparent molar absorption coefficient of 4.14×104. The composition of ternary complex is found as: Sc:GCR:CTMAB=1:2:2. For the Sc dertermination the interfreences of the diverse ions was reduced by masking with a mixture of acetylaceton and phenanthroline.The method has been used satisfactorily to determine small amount of Sc in the synthetic mixture of rare earths.
1985, 2(1): 48-53
Abstract:
The isothermal crystallization behavior of cis-1, 4polybutadiene raw rubber was studied at depressed or elevated temperature by means of a linear dilatometer. It was found that the length of some gel-containing samples increases at the beginning of crystallization, and it decreases until the crystal is melted completely. These abnomal phenomena disappear gradually with the ocess of annealing of the sample. In this paper a model of the gelcontaining sample is proposed which may preserve the internal stress by adding an external force. Owing to the internal stress preserved in the sample, the oriented gel parts form a fibrillar crystal at first stage, which lengthens the sample,then the spherical crystal formed in the sol parts reduces the length of the sample. Such interpretation is further confirmed by DSC experiments.
The isothermal crystallization behavior of cis-1, 4polybutadiene raw rubber was studied at depressed or elevated temperature by means of a linear dilatometer. It was found that the length of some gel-containing samples increases at the beginning of crystallization, and it decreases until the crystal is melted completely. These abnomal phenomena disappear gradually with the ocess of annealing of the sample. In this paper a model of the gelcontaining sample is proposed which may preserve the internal stress by adding an external force. Owing to the internal stress preserved in the sample, the oriented gel parts form a fibrillar crystal at first stage, which lengthens the sample,then the spherical crystal formed in the sol parts reduces the length of the sample. Such interpretation is further confirmed by DSC experiments.
1985, 2(1): 54-59
Abstract:
Some liguid laser solutions containing Nd3+ ion were prepared in inorganic solvents. It was found that the composition and proportion of the solvents in the solution reveal an influence on the viscosity, lifetime of 4F3/2 energy level for Nd3+ ion and output of laser energy.The high stability of the Nd3+ complex and the long lifetime of the energy level for Nd3+ ion are considered to be caused by three factors:the first coordinated sphere for Nd3+ ion is occupied by oxygen atoms, the solvation of the Nd3+-containing complexes with POCl3 molecules and the formation of
P=O→SnCl4 (donor acceptor) bonding.
Some liguid laser solutions containing Nd3+ ion were prepared in inorganic solvents. It was found that the composition and proportion of the solvents in the solution reveal an influence on the viscosity, lifetime of 4F3/2 energy level for Nd3+ ion and output of laser energy.The high stability of the Nd3+ complex and the long lifetime of the energy level for Nd3+ ion are considered to be caused by three factors:the first coordinated sphere for Nd3+ ion is occupied by oxygen atoms, the solvation of the Nd3+-containing complexes with POCl3 molecules and the formation of
P=O→SnCl4 (donor acceptor) bonding.
1985, 2(1): 60-63
Abstract:
A potassium ion-selective microelectrode based on incorporating valinomycin in the PVC matrix membrane has been designed and constructed. It is a needle shaped electrode made of glass with a tip outer diameter of 5-10μm.The concentration calibration curve of the electrode is linear over concentration range of 1×10-4-1×10-1M of K+, with detection limit 2.0×10-5MK+ and a slope 54 mV per decade. The working pH ranges 3-10. The selectivity coefficient KK,Napot is 1.12×10-4. The values of selectivity coefficients for some principal interferences, such as Li+, NH4+, Ca2+, Ba2+, Mg2+, have also been determined. The electrode can be applied in studying physiological,biochemical and clinical phenomena related to K+ activties.
A potassium ion-selective microelectrode based on incorporating valinomycin in the PVC matrix membrane has been designed and constructed. It is a needle shaped electrode made of glass with a tip outer diameter of 5-10μm.The concentration calibration curve of the electrode is linear over concentration range of 1×10-4-1×10-1M of K+, with detection limit 2.0×10-5MK+ and a slope 54 mV per decade. The working pH ranges 3-10. The selectivity coefficient KK,Napot is 1.12×10-4. The values of selectivity coefficients for some principal interferences, such as Li+, NH4+, Ca2+, Ba2+, Mg2+, have also been determined. The electrode can be applied in studying physiological,biochemical and clinical phenomena related to K+ activties.
1985, 2(1): 64-66
Abstract:
In this paper, the relationship of the degree of degradation of γ-irradiated 1,2-polybutadienes with various 1,2-unit contents to the radiation dose was studied. It is found that the sol fraction of the crosslinked samples is proportional to the β power of the radiation dose, and the lower the 1,2-unit content, the smaller the β value is. Since the molecular chain of 1,2-polybuta-diene with lower 1,2-unit content is more flexible than that with higher content, radiation behaviour of 1,2-polybutadienes relates to their chain flexibility. It is proposed that structural parameters of polymer, such as cohesion energy density and cross-sectional area of polymer chain, could be used to relate to the parameter β, that is, to the effect of structure of polymer on the radiation behaviour.
In this paper, the relationship of the degree of degradation of γ-irradiated 1,2-polybutadienes with various 1,2-unit contents to the radiation dose was studied. It is found that the sol fraction of the crosslinked samples is proportional to the β power of the radiation dose, and the lower the 1,2-unit content, the smaller the β value is. Since the molecular chain of 1,2-polybuta-diene with lower 1,2-unit content is more flexible than that with higher content, radiation behaviour of 1,2-polybutadienes relates to their chain flexibility. It is proposed that structural parameters of polymer, such as cohesion energy density and cross-sectional area of polymer chain, could be used to relate to the parameter β, that is, to the effect of structure of polymer on the radiation behaviour.
1985, 2(1): 67-69
Abstract:
Polymerization of acetylene was tested on olefin metathesis catalysts.Experiments showed that polymerization and cyclotrimerization of acetylene did occur with all the seven catalysts tested. No correlation in catalyst activity and selectivity was found between olefin metathesis and acetylene polymcrization. Ageing of the Bu4N[Mo(CO)5Cl]-EtAlCl2 system showed a tremendous decay in catalytic activity for olefin metathesis, but a minor effect on the rate of polymerzation of acetylene. It seems likely that although metathesis of olefin and polymerization of acetylenc proceed on the same catalyst, the active species is not identical. The fact that the turn over number in acetylene polymerization is very low and the polyacetylene is formed very rapidly implics the presence of very small amount of Mo or W molecules acted as active species for polymerization.
Polymerization of acetylene was tested on olefin metathesis catalysts.Experiments showed that polymerization and cyclotrimerization of acetylene did occur with all the seven catalysts tested. No correlation in catalyst activity and selectivity was found between olefin metathesis and acetylene polymcrization. Ageing of the Bu4N[Mo(CO)5Cl]-EtAlCl2 system showed a tremendous decay in catalytic activity for olefin metathesis, but a minor effect on the rate of polymerzation of acetylene. It seems likely that although metathesis of olefin and polymerization of acetylenc proceed on the same catalyst, the active species is not identical. The fact that the turn over number in acetylene polymerization is very low and the polyacetylene is formed very rapidly implics the presence of very small amount of Mo or W molecules acted as active species for polymerization.
1985, 2(1): 70-73
Abstract:
This paper deals with the reactions of the polyhedral boranes BnHn3=(n:10 or 12) with (C3H5FeC5H4CH2NMe2Cl)2 R and Fe(C5H4CH2NMe2Cl)2R(R: -(CH2)4-, -CH2C≡CCH2-). The products were characterised by elemental analysis and IR spectroscopy.Melting points of the compounds were determined by differential thermal analysis.
This paper deals with the reactions of the polyhedral boranes BnHn3=(n:10 or 12) with (C3H5FeC5H4CH2NMe2Cl)2 R and Fe(C5H4CH2NMe2Cl)2R(R: -(CH2)4-, -CH2C≡CCH2-). The products were characterised by elemental analysis and IR spectroscopy.Melting points of the compounds were determined by differential thermal analysis.
1985, 2(1): 74-76
Abstract:
The crystallization rate and tensile behavior were studied for two amorphous PET films A and B, prepared by using Sb2O3 and SnC2O4 as polycondensation catalyst respectively. It was found that sample A is more easily crystallized than sample B. Experimental results indicated that the crystallization rate is really an important factor affecting the tensile properties of PET films, and it is possible to change their processing behavior by using different catalyst.It was proposed to use area ratio at break Rb and σ10, the stress value at two tensional draw ratio=10, as parameters characterizing the processibility of PET film.
The crystallization rate and tensile behavior were studied for two amorphous PET films A and B, prepared by using Sb2O3 and SnC2O4 as polycondensation catalyst respectively. It was found that sample A is more easily crystallized than sample B. Experimental results indicated that the crystallization rate is really an important factor affecting the tensile properties of PET films, and it is possible to change their processing behavior by using different catalyst.It was proposed to use area ratio at break Rb and σ10, the stress value at two tensional draw ratio=10, as parameters characterizing the processibility of PET film.
1985, 2(1): 77-79
Abstract:
Cis 1,4-polybutadiene samples prepared with different catalysts haye different physical, mechanical properties and processibility as well.It is related to their molecular weight distribution, microstructure and contents of the branched chains. The present paper describes the characterization of various kinds of cis 1,4-polybutadiene by gel permeation chromatography (GPC) coupled with low angle laser light scattering spectrometry (LALLS). Satisfactory results are obtained for both linear and branched samples.
Cis 1,4-polybutadiene samples prepared with different catalysts haye different physical, mechanical properties and processibility as well.It is related to their molecular weight distribution, microstructure and contents of the branched chains. The present paper describes the characterization of various kinds of cis 1,4-polybutadiene by gel permeation chromatography (GPC) coupled with low angle laser light scattering spectrometry (LALLS). Satisfactory results are obtained for both linear and branched samples.
