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1987 Volume 4 Issue 1
1987, 4(1): 1-12
Abstract:
In this article,the application of equivalents in the synthesis of 1,4-dicarbonyl compounds are reviewed. The equivalents of acyl carbanion,α-acyl carbenium ion, and β-acyl carbanion are discussed.
In this article,the application of equivalents in the synthesis of 1,4-dicarbonyl compounds are reviewed. The equivalents of acyl carbanion,α-acyl carbenium ion, and β-acyl carbanion are discussed.
1987, 4(1): 13-17
Abstract:
It is found by us for the first time that using chloride silicane as the third component of rare earth based catalyst system leads not only to making catalyst, homogeneous but also to obtaining very high activity of the catalyst and stereospecifity for butadiene polymer. Polymer obtained by mehtioned catalyst system shows narrow MWD and has good physical properties of its vulcanizates.
It is found by us for the first time that using chloride silicane as the third component of rare earth based catalyst system leads not only to making catalyst, homogeneous but also to obtaining very high activity of the catalyst and stereospecifity for butadiene polymer. Polymer obtained by mehtioned catalyst system shows narrow MWD and has good physical properties of its vulcanizates.
1987, 4(1): 18-21
Abstract:
Toughened epoxy resin with good properties was produced by adding isocyanate-terminated prepolymer obtained from hydroxy-terminated butadiene-acrylonitrile copolymer and toluene diisocyanate into epoxy resin. Its dynamic mechanical properties measured by torsional braid method indicate that there are two peaks in the plot of logarithmic decrement △ against temperature above 0℃. The transmission electron micrographs show that they have two phase structures and the phase reversal occures while prepolymer content being 30 phr. This phenomenon was explained in terms of the curing of the resin.
Toughened epoxy resin with good properties was produced by adding isocyanate-terminated prepolymer obtained from hydroxy-terminated butadiene-acrylonitrile copolymer and toluene diisocyanate into epoxy resin. Its dynamic mechanical properties measured by torsional braid method indicate that there are two peaks in the plot of logarithmic decrement △ against temperature above 0℃. The transmission electron micrographs show that they have two phase structures and the phase reversal occures while prepolymer content being 30 phr. This phenomenon was explained in terms of the curing of the resin.
1987, 4(1): 22-25
Abstract:
In this paper the reactions of Pt-Sn complexes supported on γ-Al2O3 were studied by UV diffuse reflectance spectroscopy. During impregnation Pt and Sn ions were individually anchored on the surface via Cl- bridging.
In this paper the reactions of Pt-Sn complexes supported on γ-Al2O3 were studied by UV diffuse reflectance spectroscopy. During impregnation Pt and Sn ions were individually anchored on the surface via Cl- bridging.
1987, 4(1): 26-29
Abstract:
In this paper silver nitrate was extracted by N1923 quantitatively at pH=3.The effects of the acidity, concentration of NO3- and temperature on the distribution ratio D have been investigated. A mechanism of the extraction has been proposed from the results obtained by using chemical equilibrium method, constant mole method and the saturation method. It was found that the extracted compound haS a formula of Ag (RNH2)2NO3 formed by coordination bond of Ag-N. Some thermodynamics functions of the extraction process and IR and NMR spectra of the compound were discussed as well.
In this paper silver nitrate was extracted by N1923 quantitatively at pH=3.The effects of the acidity, concentration of NO3- and temperature on the distribution ratio D have been investigated. A mechanism of the extraction has been proposed from the results obtained by using chemical equilibrium method, constant mole method and the saturation method. It was found that the extracted compound haS a formula of Ag (RNH2)2NO3 formed by coordination bond of Ag-N. Some thermodynamics functions of the extraction process and IR and NMR spectra of the compound were discussed as well.
1987, 4(1): 30-34
Abstract:
This paper is concerned with the relation between the catalytic activity and pore structure of five kinds of clay from different places used as catalyst for the polymerization of cottonseed oil acid. The amount of N2 adsorption on the clays was measured by means of gas chromatography at the temperature of liquid nitrogen. The types of the pore structure of clay were estimated from the isotherms of the adsorption and desorption as well as from the DTA and SEM bbservations. The calculated results show that all the samples are rich in the porosiy of medium size. since it gives the highest yield of dimeric octadecadienoic acid, the Jilin clay which has the pore diameter of d=30-40Å showed a better specificity in the formation of the dimeric acid.
This paper is concerned with the relation between the catalytic activity and pore structure of five kinds of clay from different places used as catalyst for the polymerization of cottonseed oil acid. The amount of N2 adsorption on the clays was measured by means of gas chromatography at the temperature of liquid nitrogen. The types of the pore structure of clay were estimated from the isotherms of the adsorption and desorption as well as from the DTA and SEM bbservations. The calculated results show that all the samples are rich in the porosiy of medium size. since it gives the highest yield of dimeric octadecadienoic acid, the Jilin clay which has the pore diameter of d=30-40Å showed a better specificity in the formation of the dimeric acid.
1987, 4(1): 35-39
Abstract:
The crosslinking reaction of vinyl-carboxyl terminated tetrafuranpropylene oxide copolymer with glycidyl methacrylate has been investigated. The effects of component ratio and catalyst on the mechanical properties of the product were observed. The changes of vinyl groups and epoxy groups were followed by IR spectrum measuvement during the reaction process. The result indicates that the reaction of epoxy and carboxyl groups proceeds more difficultly than the addition reaction of vinyl groups.It is considered very important to choose an efficient catalyst to control the relative reaction rates and conversion degree of the two reactions. The number of the effective crosslinking chains per unit volume (Vo)and the average moecular weight between crosslinks (Mc) were determined by means of equilibrium swelling technique. The mechanical properties were improved with increase of crosslinking density. V., Mc and mechanical properties were influenced by the content of the catalyst used.
The crosslinking reaction of vinyl-carboxyl terminated tetrafuranpropylene oxide copolymer with glycidyl methacrylate has been investigated. The effects of component ratio and catalyst on the mechanical properties of the product were observed. The changes of vinyl groups and epoxy groups were followed by IR spectrum measuvement during the reaction process. The result indicates that the reaction of epoxy and carboxyl groups proceeds more difficultly than the addition reaction of vinyl groups.It is considered very important to choose an efficient catalyst to control the relative reaction rates and conversion degree of the two reactions. The number of the effective crosslinking chains per unit volume (Vo)and the average moecular weight between crosslinks (Mc) were determined by means of equilibrium swelling technique. The mechanical properties were improved with increase of crosslinking density. V., Mc and mechanical properties were influenced by the content of the catalyst used.
1987, 4(1): 40-43
Abstract:
In this paper, the oligomerization reaction of 1-butene has been studied using 1,1,1,5,5,5-haxafluro-2,4-pentadionato-nickel/diethyl aluminium ethoxide, (hfacac)2Ni/Et2AlOEt, as catalyst. Results showed that (hfacac)2Ni/Et2AlOEt is an efficient catalyst for linear oligomerization of 1-butene and also cata1yzes isomerization and hydrogenation of 1-butene.
In this paper, the oligomerization reaction of 1-butene has been studied using 1,1,1,5,5,5-haxafluro-2,4-pentadionato-nickel/diethyl aluminium ethoxide, (hfacac)2Ni/Et2AlOEt, as catalyst. Results showed that (hfacac)2Ni/Et2AlOEt is an efficient catalyst for linear oligomerization of 1-butene and also cata1yzes isomerization and hydrogenation of 1-butene.
1987, 4(1): 44-47
Abstract:
This paper reported the synthesis of α-methyl phenylalanine via benzylation of Schiff base (1) derived from alanine methyl ester with benzaldehyde and hydrolysis of (2) using solid-liquid phase transfer catalytic condition.The influencing factors and kinetics of benzylation of Schiff Base have been investigated. It was found that the reaction had the characteristic of surface reaction and autocatalytic reaction. A possible mechanism of solid-liquid phase transfer catalytic alkylation has been proposed.
This paper reported the synthesis of α-methyl phenylalanine via benzylation of Schiff base (1) derived from alanine methyl ester with benzaldehyde and hydrolysis of (2) using solid-liquid phase transfer catalytic condition.The influencing factors and kinetics of benzylation of Schiff Base have been investigated. It was found that the reaction had the characteristic of surface reaction and autocatalytic reaction. A possible mechanism of solid-liquid phase transfer catalytic alkylation has been proposed.
1987, 4(1): 48-52
Abstract:
In this paper, the bulk crystallization behavior of cis-1, 4-polybutadiene polymerized with rare-earth catalyst (Ln-PB) has been studied by linear dilatometry, volumetric dilatometry, DSC, TBA, and x-ray diffraction techniques. The effects of molecular weight of Ln-PB on the crystallization rate, melting point, glass temperature, and specific crystal surface free energy has been investigated in a wide range of molecular weight and crystallization temperature. It has been found that the crystallization rate increases initially with increasing the density of chain entanglement networks, through a maximum, and declines. Thereafter using secondary nucleation theory and taking into account the effect of the entanglement on the crystallization, a crystallization kinetic equation of Ln-PB which is quite adequate experimental data could be derived.
In this paper, the bulk crystallization behavior of cis-1, 4-polybutadiene polymerized with rare-earth catalyst (Ln-PB) has been studied by linear dilatometry, volumetric dilatometry, DSC, TBA, and x-ray diffraction techniques. The effects of molecular weight of Ln-PB on the crystallization rate, melting point, glass temperature, and specific crystal surface free energy has been investigated in a wide range of molecular weight and crystallization temperature. It has been found that the crystallization rate increases initially with increasing the density of chain entanglement networks, through a maximum, and declines. Thereafter using secondary nucleation theory and taking into account the effect of the entanglement on the crystallization, a crystallization kinetic equation of Ln-PB which is quite adequate experimental data could be derived.
1987, 4(1): 53-56
Abstract:
The transitions of bisphenol A and phenolphthalein oligo-polysulfones were investigated by DSC. It is found that for both the oligomers, after proper heat-treatment, two more transitions, lower and higher than their Tg,appeared on their DSC curves. It might be reasonable to suggest that these two transitions be due to the disordering of loc 1 short and long range order of molecular arrangements respectively. Equations for linear relationship between Tg and Mn for both the oligomers are given in the paper.
The transitions of bisphenol A and phenolphthalein oligo-polysulfones were investigated by DSC. It is found that for both the oligomers, after proper heat-treatment, two more transitions, lower and higher than their Tg,appeared on their DSC curves. It might be reasonable to suggest that these two transitions be due to the disordering of loc 1 short and long range order of molecular arrangements respectively. Equations for linear relationship between Tg and Mn for both the oligomers are given in the paper.
1987, 4(1): 57-61
Abstract:
The effect of frequency from 10 to 100Hz on A. C. etching of aluminum foil in hydrochloric acid has been investigated. It was found that there exists an optimum frequency fm corresponding to the relatively highest surface area magnification under certain etch condition. fm was also temperature dependent, it moves toward higher value with increase of temperature.The preferable frequency and temperature were 20Hz and 35℃ respectively. Based on the breakdown potential obtained from the oscillogram, the weight and the morphology of etch film, it may be concluded that with the frequency below fm the etch film formed was thin and it was easy to be broken through to produce a higher density of pits, which would be merged with each other ultimately, leading to a loose morphology; with the frequency higher than fm the etch film was too thick to be broken through, the etch morphology exhibited only a few large pits. Only at fm the thickness of the etch film was suitable to produce a moderate density of pits, and at last a deep layer of roughened metal was formed, giving the maximum surface area magnification.The importance of the initial aluminum surface condition in A.C. etching was also discussed.
The effect of frequency from 10 to 100Hz on A. C. etching of aluminum foil in hydrochloric acid has been investigated. It was found that there exists an optimum frequency fm corresponding to the relatively highest surface area magnification under certain etch condition. fm was also temperature dependent, it moves toward higher value with increase of temperature.The preferable frequency and temperature were 20Hz and 35℃ respectively. Based on the breakdown potential obtained from the oscillogram, the weight and the morphology of etch film, it may be concluded that with the frequency below fm the etch film formed was thin and it was easy to be broken through to produce a higher density of pits, which would be merged with each other ultimately, leading to a loose morphology; with the frequency higher than fm the etch film was too thick to be broken through, the etch morphology exhibited only a few large pits. Only at fm the thickness of the etch film was suitable to produce a moderate density of pits, and at last a deep layer of roughened metal was formed, giving the maximum surface area magnification.The importance of the initial aluminum surface condition in A.C. etching was also discussed.
1987, 4(1): 62-66
Abstract:
We have studied the effect of the plasticizer dioctyl phthalate (DOP) on oxygen-enrichment performance of polyvinyl chloride(PVC). The permeability of oxygen of poly-vinyl chloride increases pronouncedly with the content of DOP and approaches to an asymptotic value 2×10-9cm3(STP)·cm/cm·s·cm Hg,two orders higher than that of PVC without plasticizers. The separatied factor αO2/N2 decreases with the increase of the content of DOP but higher than or equals to that of PVC itself. The higher the content of DOP, the lower the glass transition temperature and hence the greater the fractional free volume of PVC.The significant effect of DOP on the permeability of oxygen could be, therefore, quite satisfactorily explained with the free volume theory of diffusion in polymers.
We have studied the effect of the plasticizer dioctyl phthalate (DOP) on oxygen-enrichment performance of polyvinyl chloride(PVC). The permeability of oxygen of poly-vinyl chloride increases pronouncedly with the content of DOP and approaches to an asymptotic value 2×10-9cm3(STP)·cm/cm·s·cm Hg,two orders higher than that of PVC without plasticizers. The separatied factor αO2/N2 decreases with the increase of the content of DOP but higher than or equals to that of PVC itself. The higher the content of DOP, the lower the glass transition temperature and hence the greater the fractional free volume of PVC.The significant effect of DOP on the permeability of oxygen could be, therefore, quite satisfactorily explained with the free volume theory of diffusion in polymers.
1987, 4(1): 67-69
Abstract:
Luminophores of (Zn-Sr)2SiO4:Tb3+ were synthesized at high temperature using SrCO3,ZnO,SiO2,Li2CO3 and Tb2(C2O4)3 as raw materials. Optimum conditions, judged by the relative intensity of illumination, were found by orthogonal design, i.e. 1200℃, Zn:Sr=0.75:0.25, SiO2=3.0 mol, Tb=0.1 mol. The properties of the product has been examined by means of x-ray powder diffraction and fluorescent spectra.
Luminophores of (Zn-Sr)2SiO4:Tb3+ were synthesized at high temperature using SrCO3,ZnO,SiO2,Li2CO3 and Tb2(C2O4)3 as raw materials. Optimum conditions, judged by the relative intensity of illumination, were found by orthogonal design, i.e. 1200℃, Zn:Sr=0.75:0.25, SiO2=3.0 mol, Tb=0.1 mol. The properties of the product has been examined by means of x-ray powder diffraction and fluorescent spectra.
1987, 4(1): 70-72
Abstract:
The 2.5th order differential pulse polarography has been investigated for titanium determination in natural water using a dropping mercury electrode. The optimum electrolyte system was found consisted of 0.02M mandelic acid and 4% potassium chlorate (PH=3), in which a well-defind neopolarogram of titanium was (observed. The negative peak potential E"np was at -0.87V (vs. SCE). A linear dependence of peak hight on titanium concentration over a range of 1×10-10-1×10-7g/ml was found. The method proved quite adequate in its sensitivity, rapidity and simplicity with recovery of 96-110% and minor inteference from a number of common ions.
The 2.5th order differential pulse polarography has been investigated for titanium determination in natural water using a dropping mercury electrode. The optimum electrolyte system was found consisted of 0.02M mandelic acid and 4% potassium chlorate (PH=3), in which a well-defind neopolarogram of titanium was (observed. The negative peak potential E"np was at -0.87V (vs. SCE). A linear dependence of peak hight on titanium concentration over a range of 1×10-10-1×10-7g/ml was found. The method proved quite adequate in its sensitivity, rapidity and simplicity with recovery of 96-110% and minor inteference from a number of common ions.
1987, 4(1): 73-74
Abstract:
Three small peaks 4', 6' and 8' in the aliphatic part of 13C-NMR spectrum of poly-butadiene (PBD) have been observed. Their appearance is considered to be related with the peaks 4,6 and 8 of the isolate 1,2-unit in PBD and to be a result of the splitting of the latter three peaks, respectively. In order to explanation these results authors of this paper consider that there must exist a new, with a higher energy level, configuration, which would show a certain shielding effect on the Cα and Cγ but decrease the shielding effect on the Cβ of the isolate 1,2-unit of PBD chain.
Three small peaks 4', 6' and 8' in the aliphatic part of 13C-NMR spectrum of poly-butadiene (PBD) have been observed. Their appearance is considered to be related with the peaks 4,6 and 8 of the isolate 1,2-unit in PBD and to be a result of the splitting of the latter three peaks, respectively. In order to explanation these results authors of this paper consider that there must exist a new, with a higher energy level, configuration, which would show a certain shielding effect on the Cα and Cγ but decrease the shielding effect on the Cβ of the isolate 1,2-unit of PBD chain.
1987, 4(1): 75-76
Abstract:
P-Acelyl-arsenazo reacts with calcium cation at pH=12.9, forming a dark-blue complex with maximum absorption at 640 nm. The molar extinction coefficient of the complex is 1.1×104. The relationship between the absorption and the concentration of the solution obeys the Beer's law, provided that Ca2+ has the concentrations within 5-50 μg/25ml.The interference of Fe3+ and Cu2+ can be eliminated by adding F- and triethanolamine, respectively. The recovery of Ca2+ added into the solutions of digested grains varys in the range of 95-110%.
P-Acelyl-arsenazo reacts with calcium cation at pH=12.9, forming a dark-blue complex with maximum absorption at 640 nm. The molar extinction coefficient of the complex is 1.1×104. The relationship between the absorption and the concentration of the solution obeys the Beer's law, provided that Ca2+ has the concentrations within 5-50 μg/25ml.The interference of Fe3+ and Cu2+ can be eliminated by adding F- and triethanolamine, respectively. The recovery of Ca2+ added into the solutions of digested grains varys in the range of 95-110%.
1987, 4(1): 77-78
Abstract:
In this paper we have attemptedto find the possibility of electrochemical approach to prepare dimethyl ester of decanedioic acid from monomethyl ester of adipic acid on the graphite anode in place of platinum. It was found that the overpotential of the oxidation reaction on graphite was about 1V lower than that on platinum electrode[1]. The yield of dimethyl ester was 15-30%.
In this paper we have attemptedto find the possibility of electrochemical approach to prepare dimethyl ester of decanedioic acid from monomethyl ester of adipic acid on the graphite anode in place of platinum. It was found that the overpotential of the oxidation reaction on graphite was about 1V lower than that on platinum electrode[1]. The yield of dimethyl ester was 15-30%.
1987, 4(1): 79-80
Abstract:
A new process for malealdehyde preparation with total yield about 58% from 1,4-dinitrobutene-2 is described.
A new process for malealdehyde preparation with total yield about 58% from 1,4-dinitrobutene-2 is described.
