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1989 Volume 6 Issue 6
1989, 6(6): 1-7
Abstract:
Through ion exchange reaction together with the use of electron pair donor organic reagents, active white powdery tungstic oxide hydrate (abbr. WPTA) can be separated into mutually convertible deca- and hexa-tungstates. A brief sketch of procedures is given inscheme 1. The success of the above mentioned method in getting deca- and hexa-tungstates promptly led to our new method of preparing deca- and hexa-tungstates through oxidation of tungsten carbide with hydrogen peroxide. Many applications of WPTA, together with different polytungstates prepared therefrom,as an extension of those listed in our previous report[3], with significant new addtions including photo-chromic polytungstates, have been hereby presented. The acidification scheme connecting sodium tungstate to yellw tungstic acid has been proposed through the incorporation of deca- and hexa-tungstates. A Brief sketch is given is scheme 2.
Through ion exchange reaction together with the use of electron pair donor organic reagents, active white powdery tungstic oxide hydrate (abbr. WPTA) can be separated into mutually convertible deca- and hexa-tungstates. A brief sketch of procedures is given inscheme 1. The success of the above mentioned method in getting deca- and hexa-tungstates promptly led to our new method of preparing deca- and hexa-tungstates through oxidation of tungsten carbide with hydrogen peroxide. Many applications of WPTA, together with different polytungstates prepared therefrom,as an extension of those listed in our previous report[3], with significant new addtions including photo-chromic polytungstates, have been hereby presented. The acidification scheme connecting sodium tungstate to yellw tungstic acid has been proposed through the incorporation of deca- and hexa-tungstates. A Brief sketch is given is scheme 2.
1989, 6(6): 8-15
Abstract:
Pig liver esterase (PLE) can stereoselectively catalyze the hydrolysis reaction of diesters giving acid-ester products in quantitative and optical yield. This paper introduces asymmetric hydrolysis of diesters and the latest achievements in asymmetric synthesis using PLE as an efficient catalyst.
Pig liver esterase (PLE) can stereoselectively catalyze the hydrolysis reaction of diesters giving acid-ester products in quantitative and optical yield. This paper introduces asymmetric hydrolysis of diesters and the latest achievements in asymmetric synthesis using PLE as an efficient catalyst.
1989, 6(6): 16-21
Abstract:
A convenient method for preparing alkenyloxymethyl crown ethers by cyclization of the corresponding substituted oligoethylene glycols with triethylene glycol ditosylate in high yield is described. The alkenyloxymethyl crown ethers, i.e. γ-allyloxymethyl 15-crown-5 & 18-crown-6, ω-undecenyloxymethyl 15-crown-5 & 18-crown-6, were subjected to hydrosilylation by triethoxysilane in the presence of tetrakis(triphenylphosphine) platinum complex,followed by immobilization on fumed silica or cohydrolysis with tetraethoxysilane to give the silica-bound polysiloxane-supported 15-crown-5, 18-crown-6, or 15-crown-5, 18-crown-6-containing silicon resins,respectively.They exhibited high complexation capacities for sodium and potassium picrate and high phase transfer catalytic activity for the anionpromoted nucleophilic substitution of n-nonyl bromide by sodium or potassium iodide.Their complexation capacities and catalytic efficiency depend on the kinds of cation in iodides, the kinds of crown ether, and the length of the spacer group. They also possessedhigh thermostability.
A convenient method for preparing alkenyloxymethyl crown ethers by cyclization of the corresponding substituted oligoethylene glycols with triethylene glycol ditosylate in high yield is described. The alkenyloxymethyl crown ethers, i.e. γ-allyloxymethyl 15-crown-5 & 18-crown-6, ω-undecenyloxymethyl 15-crown-5 & 18-crown-6, were subjected to hydrosilylation by triethoxysilane in the presence of tetrakis(triphenylphosphine) platinum complex,followed by immobilization on fumed silica or cohydrolysis with tetraethoxysilane to give the silica-bound polysiloxane-supported 15-crown-5, 18-crown-6, or 15-crown-5, 18-crown-6-containing silicon resins,respectively.They exhibited high complexation capacities for sodium and potassium picrate and high phase transfer catalytic activity for the anionpromoted nucleophilic substitution of n-nonyl bromide by sodium or potassium iodide.Their complexation capacities and catalytic efficiency depend on the kinds of cation in iodides, the kinds of crown ether, and the length of the spacer group. They also possessedhigh thermostability.
1989, 6(6): 22-26
Abstract:
The extraction of thorium in nitric acid by H2A-CHCl3 solution has been studied. The extraction equilibrium constant is found to be 1.03×106. The pH1/2 of Th(Ⅳ), Fe(Ⅲ),Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ), Cu(Ⅱ), Pb(Ⅱ), U(Ⅵ), La(Ⅲ) and Yb(Ⅲ) in nitric acid by H2A-CHCl3 are determined. A method for separating Th(Ⅳ) in monazite is proposed.
The extraction of thorium in nitric acid by H2A-CHCl3 solution has been studied. The extraction equilibrium constant is found to be 1.03×106. The pH1/2 of Th(Ⅳ), Fe(Ⅲ),Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ), Cu(Ⅱ), Pb(Ⅱ), U(Ⅵ), La(Ⅲ) and Yb(Ⅲ) in nitric acid by H2A-CHCl3 are determined. A method for separating Th(Ⅳ) in monazite is proposed.
1989, 6(6): 27-31
Abstract:
Morphology and mechanical properties of (NR+SBR)/PE blends with rubber uncured or fully cured by either dynamic or static vulcanization were studied by transmission and scanning electron microscopy. The results showed that in the case of non-vulcanization PE existed as a dispersed phase at (NR+SBR)/PE ratio(w/w) of 70/30 and as a continuous phase with ratio ≤50/50. The blends obtained by static vulcanization had the same morphology as the uncured blends. When the rubber was cured by the. dynamic method, PE always existed as a continuous phase.The tensile strength of the (NR+SBR)/PE blends increased with increase in PE content. The DSC and dynamic mechanical test results proved that method of rubber vulcanization was the prime factor responsible for the compatibility between blend components. The blends cured by static vulcanization had higher tensile strength than those by the dynamic method. This is considered as due to the difference in interpenetration between rubber and PE molecules, the penetration being in a higher degree in the static than in the dynamic vulcanization.
Morphology and mechanical properties of (NR+SBR)/PE blends with rubber uncured or fully cured by either dynamic or static vulcanization were studied by transmission and scanning electron microscopy. The results showed that in the case of non-vulcanization PE existed as a dispersed phase at (NR+SBR)/PE ratio(w/w) of 70/30 and as a continuous phase with ratio ≤50/50. The blends obtained by static vulcanization had the same morphology as the uncured blends. When the rubber was cured by the. dynamic method, PE always existed as a continuous phase.The tensile strength of the (NR+SBR)/PE blends increased with increase in PE content. The DSC and dynamic mechanical test results proved that method of rubber vulcanization was the prime factor responsible for the compatibility between blend components. The blends cured by static vulcanization had higher tensile strength than those by the dynamic method. This is considered as due to the difference in interpenetration between rubber and PE molecules, the penetration being in a higher degree in the static than in the dynamic vulcanization.
1989, 6(6): 32-37
Abstract:
Fourteen complexes of rare earth trichloride with L-cysteine were preparecd from aq.ethanol solution (Cc complex from aq. n-butanol) at pH3.5. The compounds have structu-ral formula RE(cys)3Cl3.3H2O(RE=Cc-Lu and Y,except Pm). The main infrared absorp-tion bands have been assigned. All the compounds may be classified into three groups: (1) complex of Ce which is a chain polynuclear complex with bridging bidentate ligand;(2)complexes of Pr-Ho and Y which are mononuclear complexes containing unidentate and che-lating bidentate ligands;(3) complexes of Er-Lu are the polymer containing unidentate,chelating bidentate and chelation-bridging tridentate ligands. Ln-O stretch vibration wereobserved at 412-428cm-1 and 169-197cm-1 The XPS study of Er-Lu complexes showsthat the atoms of oxygen are coordinated to lanthanide ions. but chloride anions are notcoordinated.
Fourteen complexes of rare earth trichloride with L-cysteine were preparecd from aq.ethanol solution (Cc complex from aq. n-butanol) at pH3.5. The compounds have structu-ral formula RE(cys)3Cl3.3H2O(RE=Cc-Lu and Y,except Pm). The main infrared absorp-tion bands have been assigned. All the compounds may be classified into three groups: (1) complex of Ce which is a chain polynuclear complex with bridging bidentate ligand;(2)complexes of Pr-Ho and Y which are mononuclear complexes containing unidentate and che-lating bidentate ligands;(3) complexes of Er-Lu are the polymer containing unidentate,chelating bidentate and chelation-bridging tridentate ligands. Ln-O stretch vibration wereobserved at 412-428cm-1 and 169-197cm-1 The XPS study of Er-Lu complexes showsthat the atoms of oxygen are coordinated to lanthanide ions. but chloride anions are notcoordinated.
1989, 6(6): 38-43
Abstract:
DSC, SALS, SAXS, WAXD and polarizing microscopy were used to study the crystalline structrures, equilibrium melting point and crystallization kineties of LLDPE in LLDPE/SBR blends. Its unit cell parameters, crystallite size, spherulite size and crystallinity remain unchanged when LLDPE content is above 50%. Crystallite and spherulite size decrease when LLDPE content is less than 50%. The long period of LLDPE ctystallites in the blends of various compositions is larger than that of pure LLDPE and increases with increasing SBR content. This system does not show melting point depression but gives higher chain folding free energy than pure LLDPE. Based on the above experimental observations it is concluded that in this system LLDPE and SBR are not compatible in general, but show certain extent of molecular chain mixing in the amorphous region of LLDPE.
DSC, SALS, SAXS, WAXD and polarizing microscopy were used to study the crystalline structrures, equilibrium melting point and crystallization kineties of LLDPE in LLDPE/SBR blends. Its unit cell parameters, crystallite size, spherulite size and crystallinity remain unchanged when LLDPE content is above 50%. Crystallite and spherulite size decrease when LLDPE content is less than 50%. The long period of LLDPE ctystallites in the blends of various compositions is larger than that of pure LLDPE and increases with increasing SBR content. This system does not show melting point depression but gives higher chain folding free energy than pure LLDPE. Based on the above experimental observations it is concluded that in this system LLDPE and SBR are not compatible in general, but show certain extent of molecular chain mixing in the amorphous region of LLDPE.
1989, 6(6): 44-47
Abstract:
The kinetic behavior of Zn(Ⅱ)-hematoporphyrin formation reaction in anionic and nonionic surfactant mediums has been studied by the two-exponential fitting of fluorescence decay time of the system. The metal-porphyrin intexaction mechanism and the incorporation rate equations have been suggested.The similar study of Zn(Ⅱ)-tetraphenylporphyrin system was carried out to check tbe validity of the time-resolved fluorescence approach proposed by the authors.
The kinetic behavior of Zn(Ⅱ)-hematoporphyrin formation reaction in anionic and nonionic surfactant mediums has been studied by the two-exponential fitting of fluorescence decay time of the system. The metal-porphyrin intexaction mechanism and the incorporation rate equations have been suggested.The similar study of Zn(Ⅱ)-tetraphenylporphyrin system was carried out to check tbe validity of the time-resolved fluorescence approach proposed by the authors.
1989, 6(6): 48-52
Abstract:
The adsorption process of cetyl pyridinium bromide (CPyBr) on glassy carbon (GC) electrode surface in a long optical path length thin-layer cell(LOPLTC) has been investigated by an AC impedance measurement. In the high freqency region of the AC impedance complex diagram, the capacity obtained from a large semicircle with rotation was 4 times larger than that theoretically calculated from a parallel plate condenser. In the low frequency region the impedance diagrams were related to the adsorption of CPyBr and the Warburg's impedance. A charge transfer model between the layer of CPyBr adsorbed on GC electrode surface and the bulk soluticn has been suggested. A low value of diffusion coefficient and large fluid dynamics radius of CPyBr (r=352Å) were calculated from Warburg's impedance. An equivalent circuit for the impedance in the whole frequency tested has been Euggested.
The adsorption process of cetyl pyridinium bromide (CPyBr) on glassy carbon (GC) electrode surface in a long optical path length thin-layer cell(LOPLTC) has been investigated by an AC impedance measurement. In the high freqency region of the AC impedance complex diagram, the capacity obtained from a large semicircle with rotation was 4 times larger than that theoretically calculated from a parallel plate condenser. In the low frequency region the impedance diagrams were related to the adsorption of CPyBr and the Warburg's impedance. A charge transfer model between the layer of CPyBr adsorbed on GC electrode surface and the bulk soluticn has been suggested. A low value of diffusion coefficient and large fluid dynamics radius of CPyBr (r=352Å) were calculated from Warburg's impedance. An equivalent circuit for the impedance in the whole frequency tested has been Euggested.
1989, 6(6): 53-57
Abstract:
The title. complex has been synthesized and characterized by elemental analysis, FT-IR, Raman spectrometric analysis and X-ray diffractometry. The crystal of the complex is monoclinic with space group P21/c and a=10.434(4),b=16.541(3),C=10.804(4)Å,β=111.75(3)°, V=1731.7(9)Å3 for Z=4. Dimetbyl phosphate anions coordinate with samarium atoms through double O-P-O bridges to form a Epecial network of ring-linkingring, each of which consists of twenty-four atoms. The coordination number of Sm is six,and the coordinate polyhedron about Sm is a slightly distorted octahedron.
The title. complex has been synthesized and characterized by elemental analysis, FT-IR, Raman spectrometric analysis and X-ray diffractometry. The crystal of the complex is monoclinic with space group P21/c and a=10.434(4),b=16.541(3),C=10.804(4)Å,β=111.75(3)°, V=1731.7(9)Å3 for Z=4. Dimetbyl phosphate anions coordinate with samarium atoms through double O-P-O bridges to form a Epecial network of ring-linkingring, each of which consists of twenty-four atoms. The coordination number of Sm is six,and the coordinate polyhedron about Sm is a slightly distorted octahedron.
1989, 6(6): 58-60
Abstract:
ms-Tetra (p-alkylthiophenyl) porphyrins and ms-tetra (o-alkylthiophenyl) porphyrins (alkyl=methyl, ethyl, propyl) were synthesized by refluxing the mixture of pyrrole and para or ortho (alkylthio) benzaldehydes in propionic acid or in acetic acid. Some metal complexes of these porphyrins were prepated by refluxing the mixture of the porphyrin and the corresponding metal salt in acetic acid or in DMF. All the porphyrins described were identified by visible spectrophotometry, nuclear magnetic resonance spectroscopy and elemental analysis.
ms-Tetra (p-alkylthiophenyl) porphyrins and ms-tetra (o-alkylthiophenyl) porphyrins (alkyl=methyl, ethyl, propyl) were synthesized by refluxing the mixture of pyrrole and para or ortho (alkylthio) benzaldehydes in propionic acid or in acetic acid. Some metal complexes of these porphyrins were prepated by refluxing the mixture of the porphyrin and the corresponding metal salt in acetic acid or in DMF. All the porphyrins described were identified by visible spectrophotometry, nuclear magnetic resonance spectroscopy and elemental analysis.
1989, 6(6): 61-63
Abstract:
Thermoelectric power of Nb2O5 doped β-Bi2O3 solid sclutions has been measured in air, pure O2, 0.1%NO/O2 and found to have high sensitivity to oxygen partial pressure.The possibility of developing a new type oxygen sensor based on the measurement of thermoelectric power has been discussed.
Thermoelectric power of Nb2O5 doped β-Bi2O3 solid sclutions has been measured in air, pure O2, 0.1%NO/O2 and found to have high sensitivity to oxygen partial pressure.The possibility of developing a new type oxygen sensor based on the measurement of thermoelectric power has been discussed.
1989, 6(6): 64-66
Abstract:
The solid complexes were formed in the extraction of divalent metals (Co,Ni, Cu, Zn) from their nitrate solutions by 2-ethylhexyl phosphonic acid mono (2-ethylhexyl) ester (HEH(EH)P). These complexes have been examined by elemental analysis, magnetic moment measurement and thermal analysis. The infrared spectra have been investigated for HEH(EH)P-M(Ⅱ)(M=Co,Ni,Cu,Zn). The structures of the complexes have been elucidated.
The solid complexes were formed in the extraction of divalent metals (Co,Ni, Cu, Zn) from their nitrate solutions by 2-ethylhexyl phosphonic acid mono (2-ethylhexyl) ester (HEH(EH)P). These complexes have been examined by elemental analysis, magnetic moment measurement and thermal analysis. The infrared spectra have been investigated for HEH(EH)P-M(Ⅱ)(M=Co,Ni,Cu,Zn). The structures of the complexes have been elucidated.
1989, 6(6): 67-70
Abstract:
The synthesis and growth of crystal of a new bimetallic yttrium complex are presented in this is paper. The crystal structure of the complex, [(CF3CO2)3YA1(C2H-5)2·2THF]2, was determined by a four circlc diffractometer. The erystals belong to monoclinic system with space group P21/n,a=10.173 Å,b=18.713 Å,c=14.704 Å,β=102.318°,V=2734.43 Å.Least square refinement has led to a final R of 0.070,Rw=0.064. The Y-O(PF3CO2)(THF) average distance 2.323(2.451) Å. The Al-O(CF3CO2) and Al-C(C2H5) distances average 1.840,1.998 Å respectively. The valence state of the yttrium is discussed based on the data of 1H-NMR and ESCA results. The Y-Y bond length indicated that the complex likely belongs to a cluster compound.
The synthesis and growth of crystal of a new bimetallic yttrium complex are presented in this is paper. The crystal structure of the complex, [(CF3CO2)3YA1(C2H-5)2·2THF]2, was determined by a four circlc diffractometer. The erystals belong to monoclinic system with space group P21/n,a=10.173 Å,b=18.713 Å,c=14.704 Å,β=102.318°,V=2734.43 Å.Least square refinement has led to a final R of 0.070,Rw=0.064. The Y-O(PF3CO2)(THF) average distance 2.323(2.451) Å. The Al-O(CF3CO2) and Al-C(C2H5) distances average 1.840,1.998 Å respectively. The valence state of the yttrium is discussed based on the data of 1H-NMR and ESCA results. The Y-Y bond length indicated that the complex likely belongs to a cluster compound.
1989, 6(6): 71-73
Abstract:
Adsorption of MoO42- on the neutral alumina has been carried out with the addition of anionic surfactant sodium dodecyl sulfate(SDS),cationic surfactant cetyl pyridine chloride (CPC) and non-ionic surfactant TW-20. It is found that the amount of the adsorbed MoO42- changed with pH value of the solution, and SDS, TW-20 decrease the adsorption,but CPC increases it.
Adsorption of MoO42- on the neutral alumina has been carried out with the addition of anionic surfactant sodium dodecyl sulfate(SDS),cationic surfactant cetyl pyridine chloride (CPC) and non-ionic surfactant TW-20. It is found that the amount of the adsorbed MoO42- changed with pH value of the solution, and SDS, TW-20 decrease the adsorption,but CPC increases it.
1989, 6(6): 74-76
Abstract:
This paper reports the use of the oscillographic indication technique in the kinetic method of analysis.The product resulted from the kinetic reaction in KBrO3-KBr-HCl system is used as a titrant and the zero current oscillographic bipotentiometric titration technique is used to indicate the end point. The results obtained with KBrO3-KBr-HCl system show that this method can be used to determine reducing substances such as As(Ⅲ),ascorbic acid,ete.and has a sensitivity about 10-6-10-7mol/dm3.This method is directly visible and rapid and needs only simple equipment.
This paper reports the use of the oscillographic indication technique in the kinetic method of analysis.The product resulted from the kinetic reaction in KBrO3-KBr-HCl system is used as a titrant and the zero current oscillographic bipotentiometric titration technique is used to indicate the end point. The results obtained with KBrO3-KBr-HCl system show that this method can be used to determine reducing substances such as As(Ⅲ),ascorbic acid,ete.and has a sensitivity about 10-6-10-7mol/dm3.This method is directly visible and rapid and needs only simple equipment.
1989, 6(6): 77-78
Abstract:
Pate's method for synthesis of N,N,N',N'-tetrabenzylethylene diamine has been improved and the thermoanalytical lesults of its solid complexes with hydrated copper chloride are reported.
Pate's method for synthesis of N,N,N',N'-tetrabenzylethylene diamine has been improved and the thermoanalytical lesults of its solid complexes with hydrated copper chloride are reported.
1989, 6(6): 79-82
Abstract:
The stability of foams has been studied in aqueous and nonaqueous solutions of various surfactants. In aqueous and ethylene glycol solution of surfactants, surface viscosity played an important role in stabilizing foams.Presence of liquid crystal increased the surface viscosity as well as the viscosity of bulk solution and as a consequence increased the stability of the foam. In xylene and n-hexane solutios of surfactants the stability of the foam was very poor,for the molecules of the surfactant were incapable of forming adsorption film in the airsolution interface. In case the concentration of the surfactants was much higher than that of the non-polar solvent in foaming system,the foam stability could be enhanced by liquid crystal. Silicone oil appeared a good defoaming agent in aqueous system, but it became bad when the amount of the liquid crystal increased.
The stability of foams has been studied in aqueous and nonaqueous solutions of various surfactants. In aqueous and ethylene glycol solution of surfactants, surface viscosity played an important role in stabilizing foams.Presence of liquid crystal increased the surface viscosity as well as the viscosity of bulk solution and as a consequence increased the stability of the foam. In xylene and n-hexane solutios of surfactants the stability of the foam was very poor,for the molecules of the surfactant were incapable of forming adsorption film in the airsolution interface. In case the concentration of the surfactants was much higher than that of the non-polar solvent in foaming system,the foam stability could be enhanced by liquid crystal. Silicone oil appeared a good defoaming agent in aqueous system, but it became bad when the amount of the liquid crystal increased.
1989, 6(6): 83-85
Abstract:
For the titration reaction aA+bB=AaBb,where A and B is the electrogenerated titrant and the substance to be determined respectively,following formula can be derived for combined coulombmetric——new polarographic determination. WB=(biMB)/(anAF(t1+(h1/(h1-h2))t2) where WB=the weight of substance to be determined, i=current used in coulombmetry,t1,t2 are times of electrogeneration adopted near tbe cnd point of titration for B or slightly over the cnd point for A,h1,h2 are corresponding heights of current peak in. new polarographic determination of A or B at t1 and t2 respectively, MB=formula weight of B,nA=electron tranfer number formation of A.
For the titration reaction aA+bB=AaBb,where A and B is the electrogenerated titrant and the substance to be determined respectively,following formula can be derived for combined coulombmetric——new polarographic determination. WB=(biMB)/(anAF(t1+(h1/(h1-h2))t2) where WB=the weight of substance to be determined, i=current used in coulombmetry,t1,t2 are times of electrogeneration adopted near tbe cnd point of titration for B or slightly over the cnd point for A,h1,h2 are corresponding heights of current peak in. new polarographic determination of A or B at t1 and t2 respectively, MB=formula weight of B,nA=electron tranfer number formation of A.
1989, 6(6): 86-88
Abstract:
An indirect electro-oxidation-method for the preparation of activated manganese dioxide is proposed based on the following electrocatalytic reactions:Ag+→Ag2++e
2Ag2++Mn2++2H20→MnO2+2Ag++4H+ The process carried out at room temperature with current density of ten to seventy times as that used in the commercial process, The product (ECMD) had discharge capacity 11.5% more than that of EMD obtained by direct electrooxidation,The amount of combined water and the apparent surface area were 13.4% and 83.3 m2·g-1, but 3.9% and 52.2 m2·g-1 for EMD sample respectively, The ECMD obtained contained 4.2% silver oxide.
An indirect electro-oxidation-method for the preparation of activated manganese dioxide is proposed based on the following electrocatalytic reactions:Ag+→Ag2++e
2Ag2++Mn2++2H20→MnO2+2Ag++4H+ The process carried out at room temperature with current density of ten to seventy times as that used in the commercial process, The product (ECMD) had discharge capacity 11.5% more than that of EMD obtained by direct electrooxidation,The amount of combined water and the apparent surface area were 13.4% and 83.3 m2·g-1, but 3.9% and 52.2 m2·g-1 for EMD sample respectively, The ECMD obtained contained 4.2% silver oxide.
1989, 6(6): 89-91
Abstract:
ESR spectra of zirconium in ZrCl4/AlEt2Cl and ZrCll4/AlEt2Cl-n-C4H9ONa catalyst systems were recorded at various reaction times, the g=1.978, Hpp=22.4×104T. The spin concentrations were determined for two systems. It is shown that Zr4+ is first reduced to Zr3+,which is further reduced to lower state. The reduction rate of Zr4+ and Zr3+ in ZrCl4/AlEt2Cl-n-C4H9ONa system is lower than that in ZrCl4/AlEt2Cl system. This fact indicates that n-C4H9ONa plays an importent role in restraining reduction of Zr4+ and Zr3+.
ESR spectra of zirconium in ZrCl4/AlEt2Cl and ZrCll4/AlEt2Cl-n-C4H9ONa catalyst systems were recorded at various reaction times, the g=1.978, Hpp=22.4×104T. The spin concentrations were determined for two systems. It is shown that Zr4+ is first reduced to Zr3+,which is further reduced to lower state. The reduction rate of Zr4+ and Zr3+ in ZrCl4/AlEt2Cl-n-C4H9ONa system is lower than that in ZrCl4/AlEt2Cl system. This fact indicates that n-C4H9ONa plays an importent role in restraining reduction of Zr4+ and Zr3+.
