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1987 Volume 4 Issue 6
1987, 4(6): 1-6
Abstract:
In this paper, the abilities of ms-tetra (2-imidazolyl) porphyrin and ms-tetra (4 or 5-imidazolyl) porphyrin to form metal complexes with zinc cation have been compared with that of ms-tetraphenylporphyrin. The catalytic activities of metal complexes of ms-tetraimi-dazolylporphyrins have been investigated in the oxidation of hydroquinone, isopropylmercap-tane and ascorbic acid with molecular oxygen. The net charge distribation and orbital energy of H2P, H2TPP, H2T(5-I)P and their zinc complexes have been calculated with EHMO programe. The data explained the experimental results satisfactorily. The results showed that the complex abilities of the porphyrins and the catalytic activities of their metal complexes increased after the imidazolyl groups were introduced into the porphyrin ring.
In this paper, the abilities of ms-tetra (2-imidazolyl) porphyrin and ms-tetra (4 or 5-imidazolyl) porphyrin to form metal complexes with zinc cation have been compared with that of ms-tetraphenylporphyrin. The catalytic activities of metal complexes of ms-tetraimi-dazolylporphyrins have been investigated in the oxidation of hydroquinone, isopropylmercap-tane and ascorbic acid with molecular oxygen. The net charge distribation and orbital energy of H2P, H2TPP, H2T(5-I)P and their zinc complexes have been calculated with EHMO programe. The data explained the experimental results satisfactorily. The results showed that the complex abilities of the porphyrins and the catalytic activities of their metal complexes increased after the imidazolyl groups were introduced into the porphyrin ring.
1987, 4(6): 7-13
Abstract:
Liquid poly-butadiene telomers (Mn800-3000, vinyl content 10-60%) were prepared by using n-butyl lithium-potassium butoxide as catalyst, toluene as solvent, with the addition of different polar modifiers (TMEDA, 4G, 2G, HMPA). The effects of concentration and composition of initiator, concentration of polar modifiers, temperature etc. on the reaction were investigated. The optimal reaction conditions determined were:concentration of initiator k'=1-2mol×10-3/75g Bd, relative composition of initiator k"=0.1-0.6, reaction temperature 40-70℃, relative composition of polar modifier k"'≤3.0 (TMEDA).
Liquid poly-butadiene telomers (Mn800-3000, vinyl content 10-60%) were prepared by using n-butyl lithium-potassium butoxide as catalyst, toluene as solvent, with the addition of different polar modifiers (TMEDA, 4G, 2G, HMPA). The effects of concentration and composition of initiator, concentration of polar modifiers, temperature etc. on the reaction were investigated. The optimal reaction conditions determined were:concentration of initiator k'=1-2mol×10-3/75g Bd, relative composition of initiator k"=0.1-0.6, reaction temperature 40-70℃, relative composition of polar modifier k"'≤3.0 (TMEDA).
1987, 4(6): 14-17
Abstract:
In this paper, the preparation, crystal structure and spectral properties of M2Y0.94RE0.06NbO6(M=Ca, Sr, Ba; RE=Eu, Sm, Dy) have been studied. The X-ray powder diffraction data and Eu3+-emission spectra showed that Ca2Y0.94Eu0.06NbO6 with distorted perovskite structue belongs to monoclinic system, the site symmetry may be C2 or Cs; Sr2Y0.94Eu0.06NbO6 and Ba2Y0.94 Eu0.06 NbO6 with ordered perovskite structure belong to cubic system the site symmetry may be Oh. It is found that the spectral properties of Eu3+, Sm3+ and Dy3+ intensify regularly in order of Ba-Sr-Ca.
In this paper, the preparation, crystal structure and spectral properties of M2Y0.94RE0.06NbO6(M=Ca, Sr, Ba; RE=Eu, Sm, Dy) have been studied. The X-ray powder diffraction data and Eu3+-emission spectra showed that Ca2Y0.94Eu0.06NbO6 with distorted perovskite structue belongs to monoclinic system, the site symmetry may be C2 or Cs; Sr2Y0.94Eu0.06NbO6 and Ba2Y0.94 Eu0.06 NbO6 with ordered perovskite structure belong to cubic system the site symmetry may be Oh. It is found that the spectral properties of Eu3+, Sm3+ and Dy3+ intensify regularly in order of Ba-Sr-Ca.
1987, 4(6): 18-21
Abstract:
This paper studied the relations between the branching degrees and photosensitivities, and the solvent resistance of cinnamate epoxy resins with branched chains. The results showed that within the critical molecular weight of entanglement chains, the photosensitivities and the solvent resistance of the resins were improved greatly with the increase of the branching degree.
This paper studied the relations between the branching degrees and photosensitivities, and the solvent resistance of cinnamate epoxy resins with branched chains. The results showed that within the critical molecular weight of entanglement chains, the photosensitivities and the solvent resistance of the resins were improved greatly with the increase of the branching degree.
1987, 4(6): 22-26
Abstract:
The crystal structures of PrCl3·C10H20O5 and SmCl13·C10H20O5 have been determined, by X-ray diffraction analysis. The complexes are. isomorph, and monoclinic with space group P21/c and lattice parameters:a=8.167(2)[8.129(7)], b=14.225(3)[14.176(7)], c=14.208(4[14.117(5)]Å, β=104.78(2)[104.62(5)]° and Z=4. The rare earth ion is bonded to the three chlorine atoms on one side and to five oxygen atoms of the crown ether on the opposite side forming an irregular 8-coordinate polyhedron. Mean bond lengths of Ln-O 2.606[2.566]Å, of Ln-Cl, 2.714[2.666]Å, they are shorter than those in higher coordinate complexes.
The crystal structures of PrCl3·C10H20O5 and SmCl13·C10H20O5 have been determined, by X-ray diffraction analysis. The complexes are. isomorph, and monoclinic with space group P21/c and lattice parameters:a=8.167(2)[8.129(7)], b=14.225(3)[14.176(7)], c=14.208(4[14.117(5)]Å, β=104.78(2)[104.62(5)]° and Z=4. The rare earth ion is bonded to the three chlorine atoms on one side and to five oxygen atoms of the crown ether on the opposite side forming an irregular 8-coordinate polyhedron. Mean bond lengths of Ln-O 2.606[2.566]Å, of Ln-Cl, 2.714[2.666]Å, they are shorter than those in higher coordinate complexes.
1987, 4(6): 27-30
Abstract:
This paper presents a detail study on the structure and switching properties of liquid crystalline copolymers of cholesteric ester of 1,2-hydroxypropyl 2,4-diisocyanatoluene methylmethacrylate (PCHPM). Under certain conditions PCHPM was observed turning into liquid crystalline state by crossed polarizers.The optical properties of the copolymers were determined by specific rotation, circular dichroism and wide-angle light scattering measurements,
This paper presents a detail study on the structure and switching properties of liquid crystalline copolymers of cholesteric ester of 1,2-hydroxypropyl 2,4-diisocyanatoluene methylmethacrylate (PCHPM). Under certain conditions PCHPM was observed turning into liquid crystalline state by crossed polarizers.The optical properties of the copolymers were determined by specific rotation, circular dichroism and wide-angle light scattering measurements,
1987, 4(6): 31-36
Abstract:
A theoretical and experimental investigation of square wave voltammetry, especially its cyclic techniques for reversible electrode processes with home-made microcomputer-based electrochemical system are described. The mathematical expressions of current functions for cyclic square wave voltammetry have been developed. It was shown theoretically and experimentally that the peak current and peak potential of the voltammogram for forward sweep are respectively equal to those for reverse sweep with the cyclic square wave voltammetric techniques.These are the important characteristics and criteria of reversible electrode processes when both the oxidation state and reduction state of electroactive analyte are soluble in the electrolyte. The effects of parameters, such as square wave amplitude (Esw),square wave pariod(τ),staircase potential increment (ΔE),were investigated.The theoretial expectations are in agreement with experimental results obtained by microcomputer-based electrochemical instrumentation.
A theoretical and experimental investigation of square wave voltammetry, especially its cyclic techniques for reversible electrode processes with home-made microcomputer-based electrochemical system are described. The mathematical expressions of current functions for cyclic square wave voltammetry have been developed. It was shown theoretically and experimentally that the peak current and peak potential of the voltammogram for forward sweep are respectively equal to those for reverse sweep with the cyclic square wave voltammetric techniques.These are the important characteristics and criteria of reversible electrode processes when both the oxidation state and reduction state of electroactive analyte are soluble in the electrolyte. The effects of parameters, such as square wave amplitude (Esw),square wave pariod(τ),staircase potential increment (ΔE),were investigated.The theoretial expectations are in agreement with experimental results obtained by microcomputer-based electrochemical instrumentation.
1987, 4(6): 37-41
Abstract:
The experimental results showed that H3PW12O4 and its salts are effective catalysts for oxidative dehydrogenation of ethylbenzene to styrene. The selectivity was as high as 98% at 18% conversion.Their activities were nearly the same regardless of their differences in acid strength and acidity. The most important feature of this reaction system appeared that the catalytic activity increases with reaction time in the beginning period, the "Break-in" period. During the "Break-in" the H/C ratio of coke decreases, while the amount of coke formed on the catalyst surface increases. some quinoid compounds were detected by thin layer chromatography and mass spectrometry and they are considered to be the active sites of tbe oxidative dehydrogenation of ethylbenzene.
The experimental results showed that H3PW12O4 and its salts are effective catalysts for oxidative dehydrogenation of ethylbenzene to styrene. The selectivity was as high as 98% at 18% conversion.Their activities were nearly the same regardless of their differences in acid strength and acidity. The most important feature of this reaction system appeared that the catalytic activity increases with reaction time in the beginning period, the "Break-in" period. During the "Break-in" the H/C ratio of coke decreases, while the amount of coke formed on the catalyst surface increases. some quinoid compounds were detected by thin layer chromatography and mass spectrometry and they are considered to be the active sites of tbe oxidative dehydrogenation of ethylbenzene.
1987, 4(6): 42-47
Abstract:
In determination of polymer transitions by inverse gas chromatography (IGC),traditionally, specimen of sample coated beads and intermittent heating technique have been employed Instead, in this work, the experimental procedure was simplified by using powder specimen and continuous heating to investigate the possibility of establishing a fast method for determining polymer transitions. Our results show that the proposed method is feasible and that the use of peak height vs temperature plot for characterizing the transitions and other structural changes of a polymer will further simplify the treatment of experimental data.
In determination of polymer transitions by inverse gas chromatography (IGC),traditionally, specimen of sample coated beads and intermittent heating technique have been employed Instead, in this work, the experimental procedure was simplified by using powder specimen and continuous heating to investigate the possibility of establishing a fast method for determining polymer transitions. Our results show that the proposed method is feasible and that the use of peak height vs temperature plot for characterizing the transitions and other structural changes of a polymer will further simplify the treatment of experimental data.
1987, 4(6): 48-53
Abstract:
The thermal oxidation of polyacetylene (PA) was studied by thermogravity(TG) and infrared spectroscopy. Effects of polymerization catalysts and cis-trans configurations of PA and atmosphere were examined. Obvious induction effect was observed for the PA prepared with Nd-catalyst. Kinetic analysis of the TG data showed that the thermal oxidation was approximately of first order for both PA and O2 concentrations and the apparent activation energy was 42±6kJ/mol for cis-PA and 51±6kJ/mol for trans-PA. Based on the variation of the IR bands with oxidation time, possible oxidation reactions were deduced.
The thermal oxidation of polyacetylene (PA) was studied by thermogravity(TG) and infrared spectroscopy. Effects of polymerization catalysts and cis-trans configurations of PA and atmosphere were examined. Obvious induction effect was observed for the PA prepared with Nd-catalyst. Kinetic analysis of the TG data showed that the thermal oxidation was approximately of first order for both PA and O2 concentrations and the apparent activation energy was 42±6kJ/mol for cis-PA and 51±6kJ/mol for trans-PA. Based on the variation of the IR bands with oxidation time, possible oxidation reactions were deduced.
1987, 4(6): 54-58
Abstract:
Critical current densitiy is defined as the minimum value of the current density necessary to start the redox reactions of mercury and supporting electrolyte in oscillopolarogram respectively. The equations of the critical current density have been derived and were found to be characteristic for a given solution. Methods for their measurement and the properties of the critical currents are discussed in this paper. The theoretical results have been confirmed experimentally.
Critical current densitiy is defined as the minimum value of the current density necessary to start the redox reactions of mercury and supporting electrolyte in oscillopolarogram respectively. The equations of the critical current density have been derived and were found to be characteristic for a given solution. Methods for their measurement and the properties of the critical currents are discussed in this paper. The theoretical results have been confirmed experimentally.
1987, 4(6): 59-63
Abstract:
The pyrolysis reaction of a chinese coking coal "Feng-Feng" has been studied in this work. The overall process is treated based on a single first order decomposition model. The results show that the Arrhenious equation could only be used at the temperature lower than 700℃ with an activation energy E=46kJ/mol. The pyrolysis reaction was assumed to consist of a series of independent irreversible parallel reactions, a statistical distribution function f(E) for activation energy could be obtained. The results show that f(E) obeyed Gaussian normal statistcal distribution and the most probable activation energy was E=259kJ/mol. The volatile speciees of the coal were analyzed.The major constituent in all cases was found to be methane. It could be assumed that CH4 came from two ways:pyrolysis reaction itself and the sccondary reactions or other volatile products.
The pyrolysis reaction of a chinese coking coal "Feng-Feng" has been studied in this work. The overall process is treated based on a single first order decomposition model. The results show that the Arrhenious equation could only be used at the temperature lower than 700℃ with an activation energy E=46kJ/mol. The pyrolysis reaction was assumed to consist of a series of independent irreversible parallel reactions, a statistical distribution function f(E) for activation energy could be obtained. The results show that f(E) obeyed Gaussian normal statistcal distribution and the most probable activation energy was E=259kJ/mol. The volatile speciees of the coal were analyzed.The major constituent in all cases was found to be methane. It could be assumed that CH4 came from two ways:pyrolysis reaction itself and the sccondary reactions or other volatile products.
1987, 4(6): 64-68
Abstract:
In this paper the effect of colouring temperature, colouring time and particularly heat treatment on the colouring of plate glass by silver diffusion has been reported. XPS,AES and EDAX were used to study the composition of the coloured layer and the state of colouring material in plate glass. The results showed that the effective eomponent in colouring agent is AgO before heat treatment, which then changes into metallic silver after heat treatment. The shade of coloured glass got deepened probably due to the particle growth of the colloidal silver after heat treatment.
In this paper the effect of colouring temperature, colouring time and particularly heat treatment on the colouring of plate glass by silver diffusion has been reported. XPS,AES and EDAX were used to study the composition of the coloured layer and the state of colouring material in plate glass. The results showed that the effective eomponent in colouring agent is AgO before heat treatment, which then changes into metallic silver after heat treatment. The shade of coloured glass got deepened probably due to the particle growth of the colloidal silver after heat treatment.
1987, 4(6): 69-72
Abstract:
The performance of crosslinked copolymer of organosioxane (CGC) in forming homogeneous and composite membranes was studied. It is found that the CGC possesses outstanding membrane-forming properties and the surface texture of the homogeneous membrane is more fine. A pinhole free ultrathin membrane with thickness of 230-250 Å was prepared by spreading on water. The CGC, as a polymeric surfactant, can markedly improve the.mombraneformation of such polyolefins as poly-4-methylpentene-1, polybutadiene etc.With polydime-thylsiloxane segment ranging from 60 to 70 Wt% the homogenteous membrane gave PO2 value of 2.5-2.7×10-8cm3 (STP)-cm/cm2·s·cm Hg and αo2/N2 of 2.2-2.3. The composite membrane obtained by laminating CGC and modified poly-4-methylpentene-1 ultrathin membra nesalternately on Celgard 2400, showed permselectivity for oxygen/nitrogen, Jo2=3.43×10-4cm3/cm2·s·cmHg, and αo2/N2=2.52.
The performance of crosslinked copolymer of organosioxane (CGC) in forming homogeneous and composite membranes was studied. It is found that the CGC possesses outstanding membrane-forming properties and the surface texture of the homogeneous membrane is more fine. A pinhole free ultrathin membrane with thickness of 230-250 Å was prepared by spreading on water. The CGC, as a polymeric surfactant, can markedly improve the.mombraneformation of such polyolefins as poly-4-methylpentene-1, polybutadiene etc.With polydime-thylsiloxane segment ranging from 60 to 70 Wt% the homogenteous membrane gave PO2 value of 2.5-2.7×10-8cm3 (STP)-cm/cm2·s·cm Hg and αo2/N2 of 2.2-2.3. The composite membrane obtained by laminating CGC and modified poly-4-methylpentene-1 ultrathin membra nesalternately on Celgard 2400, showed permselectivity for oxygen/nitrogen, Jo2=3.43×10-4cm3/cm2·s·cmHg, and αo2/N2=2.52.
1987, 4(6): 73-75
Abstract:
Cyclopropanation of dimethyl maleate with dibromomethane catalyzed by in situ generated Co(0)-or Ni(0)-complex under ultrasonic waves is reported in this paper. The ultrasound accelerates the formation of intermediate complexes:Co(E-H3CO2CH-CHCO2CH3)2(CH3CN)2 and Ni(Z-H3CO2CH=CHCO2CH3)2CH3CN, increases the yield of the reaction product and reduces the reaction time. An adequate method for dimethyl 1,2-cyclopropane-dicarboxylate preparation is described.
Cyclopropanation of dimethyl maleate with dibromomethane catalyzed by in situ generated Co(0)-or Ni(0)-complex under ultrasonic waves is reported in this paper. The ultrasound accelerates the formation of intermediate complexes:Co(E-H3CO2CH-CHCO2CH3)2(CH3CN)2 and Ni(Z-H3CO2CH=CHCO2CH3)2CH3CN, increases the yield of the reaction product and reduces the reaction time. An adequate method for dimethyl 1,2-cyclopropane-dicarboxylate preparation is described.
1987, 4(6): 76-78
Abstract:
Plasma polymerization of toluenediisocyanate(TDI) was carried out in inductively coupled glow discharge(13.56MHz), and the polymer deposition kinetics and distribution are determined. The polymerization product has been characterized by elemental analysis and infrared spectrometry measurements.
Plasma polymerization of toluenediisocyanate(TDI) was carried out in inductively coupled glow discharge(13.56MHz), and the polymer deposition kinetics and distribution are determined. The polymerization product has been characterized by elemental analysis and infrared spectrometry measurements.
1987, 4(6): 79-81
Abstract:
An improvement was achieved by impregnation of the Y-9 catalyst with rare earth nitrates.The experimental results showed that addition of rare earth oxides in Y-9 catalyst can increase the cracking activity of the catalyst, reduce the amount of carbon daposited on the surface of the catalyst, and accelarate the combustion of deposited Carbon. The crystal planes of the catalyst can be readily restored after combustion of the deposited carbon.
An improvement was achieved by impregnation of the Y-9 catalyst with rare earth nitrates.The experimental results showed that addition of rare earth oxides in Y-9 catalyst can increase the cracking activity of the catalyst, reduce the amount of carbon daposited on the surface of the catalyst, and accelarate the combustion of deposited Carbon. The crystal planes of the catalyst can be readily restored after combustion of the deposited carbon.
1987, 4(6): 82-84
Abstract:
The direct polycondensation for polyester synthesis was investigated by visible light and IR spectroscopy measurements. The results showed that pyridine not only acts as a solvent but also reacts with tosyl chloride to form an intermediate and that DMF catalyzes the formation of the intermediate. A mechanism is proposed.
The direct polycondensation for polyester synthesis was investigated by visible light and IR spectroscopy measurements. The results showed that pyridine not only acts as a solvent but also reacts with tosyl chloride to form an intermediate and that DMF catalyzes the formation of the intermediate. A mechanism is proposed.
1987, 4(6): 85-87
Abstract:
The influences of the contents of Sb and As in the lead base alloys on the corrosion weight loss and mechanical properties were studied. The grid alloy containing 3.5% antimony and 0.15% As was scrcened for low maintenance lead acid batteries. The results indicated that the crystal structure and distribution of antimony in alloy were affected oviously by thbe addition of As. The influence of Sb and As on the corrosion weight loss and mechanical properties is discussed.
The influences of the contents of Sb and As in the lead base alloys on the corrosion weight loss and mechanical properties were studied. The grid alloy containing 3.5% antimony and 0.15% As was scrcened for low maintenance lead acid batteries. The results indicated that the crystal structure and distribution of antimony in alloy were affected oviously by thbe addition of As. The influence of Sb and As on the corrosion weight loss and mechanical properties is discussed.
1987, 4(6): 88-89
Abstract:
The synthetic method of 4,4'-tetramethyldiaminodiphenylmethane has been improved using oxalic acid and hydrochloric acid as catalysts. The optimum reaction conditions of the synthesis are:(1) the molar ratio of N,N-dimethylaniline to formaldehyde:1.7:1, (2) weight of oxalic acld and hydrochloric acid:74% and 14% to the weight of N,N-dimethylaniline, respectively and (3) reaction time:3 hours.
The synthetic method of 4,4'-tetramethyldiaminodiphenylmethane has been improved using oxalic acid and hydrochloric acid as catalysts. The optimum reaction conditions of the synthesis are:(1) the molar ratio of N,N-dimethylaniline to formaldehyde:1.7:1, (2) weight of oxalic acld and hydrochloric acid:74% and 14% to the weight of N,N-dimethylaniline, respectively and (3) reaction time:3 hours.
