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21.
V. V. Korshak K. K. Mozgova Yu. V. Egorova 《Journal of polymer science. Part A, Polymer chemistry》1968,6(10):2715-2727
Repeatedly grafted copolymers (pemosors) were obtained by grafting one and the same or different vinyl monomers onto heterochain polymers in a radical reaction. As starting polymers films of polyethylene terephthalate and poly-ε-caproamide were used. Styrene and methyl methacrylate were the grafted vinyl monomers. It has been shown that pemosors could be formed in yields of 500–1000% (of the starting sample weight) by multiple grafting on vinyl polymer. Pemosors differ in appearance both from the starting polymers and the single-graft copolymers. Investigations of pemosor samples by electron microscope showed that the morphological structure of the surface was appreciably affected, the changes being more significant with increasing content of the grafted polymer. X-Ray studies and NMR data on pemosors showed that multiple grafting of vinyl monomers does not change the crystal structure of the starting polymers, affecting only the supermolecular structure of the outer layer. Pemosors are polymers of a new type, differing in their properties from the starting polymers and the single-graft copolymers. The grafting character and penetration depth of the grafted monomer depend on the packing compactness of the supermolecular structure of the polymeric base as well as on the chemical nature of the starting polymers and monomers. Pemosors possess considerable chemical resistance and withstand prolonged boiling in 40% alkali solution. 相似文献
22.
The aminolysis of 5-aryl-3-arylidene-3H-furan-2-ones by the action of aromatic amines leads to the formation of substituted amides of 4-oxo acids, the subsequent azacyclization of which in the presence of acetic anhydride leads to the formation of 1,5-diaryl-substituted 3-arylidene-3H-pyrrol-2-ones. The mechanism of the occurring and alternative transformations is discussed. 相似文献
23.
24.
The Michael condensation in the series of 5-aryl-3H-furan-2-ones with chalcones containing electron-donating substituents was studied. In the case of ,-unsaturated ketones containing an electrondonating substituent, the reaction does not stop at the stage of formation of 1,5-dicarbonyl compounds but is accompanied by intramolecular cyclodehydration yielding a new series of furo[2,3-b]-4H-pyrans. A mechanism of formation of these products was suggested. The structure of reaction products was proved by IR and 1H NMR spectroscopy. 相似文献
25.
Lamberov A. A. Levin O. V. Egorova S. R. Evstyagin D. A. Aptikasheva A. G. 《Russian Journal of Applied Chemistry》2003,76(3):351-357
The method of low-temperature adsorption of nitrogen was applied to study structural characteristics of commercial peptized aluminum hydroxides. An increase or decrease in the porometric volume, depending on the nature and concentration of the peptizing agent, was analyzed. The phenomena observed are explained in terms of the mechanism suggested for formation of the pore system in commercial aluminum hydroxides. The dependence of the physicomechanical properties of active aluminum oxide on synthesis conditions and texture characteristics of commercial aluminum hydroxides was studied. 相似文献
26.
L. B. Naumova L. A. Egorova A. A. Slivinskaya 《Russian Journal of Applied Chemistry》2006,79(2):236-240
The influence exerted by modifying additives of inorganic nature on the hydrophilicity of peats from the Orlovskoe deposit in Tomsk oblast and on their thermal stability was studied. The acid-base, equilibrium, and kinetic properties of the starting peat samples and those modified with solutions of iron(III) and aluminum chlorides were examined. Their physicochemical parameters were determined: total exchange capacity, acidity by acid and basic groups, relative humidity, distribution coefficients, effective diffusion coefficients, and activation energy. The effect of modifying cations on the thermal decomposition of peat was analyzed. 相似文献
27.
Sharutin V. V. Sharutina O. K. Senchurin V. S. Egorova I. V. Ivanenko T. K. Petrov B. I. 《Russian Journal of General Chemistry》2003,73(2):202-203
Pentaphenylantimony and -phosphorus react with arylmercury chlorides in toluene at room temperature to give diaryl derivatives of mercury in yields of up to 95%. The reactions of pentaphenylantimony and -phosphorus with silicon and tin halides involve arylation of the latter in yields of up to 79%. The products of the reaction of pentaphenylphosphorus with triphenylbismuth dihalides are tetraphenylphosphorus halides, triphenylbismuth, and halobenzene. 相似文献
28.
Ira W. Herbst 《Communications in Mathematical Physics》1980,75(3):197-205
LetH=–+V+Fx
1 withV(x
1,x
) analytic in the first variable andV(x
1+ia, x
) bounded and decreasing to zero asx for eacha . Let be an eigenvector of –+V with negative eigenvalue. Among our results we show that forF0, (,e
–H
) decays exponentially at a rate governed by the positions of the resonances ofH. This exponential decay is in marked contrast to conventional atomic resonances for which power law decay is the rule.Research supported by NSF Grant No. MCS 78-00101. 相似文献
29.
A. P. Novikova N. M. Perova L. G. Egorova E. I. Bragina 《Chemistry of Heterocyclic Compounds》1991,27(6):666-668
2-Amino-5-aryl(pyridyl)-6H-1,3,4-thiadiazines ana isomeric 2-hydrazino-4-aryl(pyridyl)thiazoles, the ratio of which depends on the reaction conditions, were obtained by the reaction of substituted phenacyl bromides and bromoacetylpyridines with thiosemicarbazide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 843–846, June, 1991. 相似文献
30.
Sharutin V. V. Sharutina O. K. Egorova I. V. Ivanenko T. K. Bel'skii V. K. 《Russian Journal of General Chemistry》2002,72(1):44-45
The reaction of triphenylbismuth dichloride with sodium fluoride in acetone leads to formation of triphenylbismuth difluoride in 73% yield. The X-ray diffraction data show that the bismuth atom in the two symmetrically independent molecules of bismuth difluoride has a trigonal-bipyramidal coordination with equatorial fluorine atoms. The Bi-F and Bi-C distances are 2.53(1)-2.59(1) and 2.10(3)-2.22(2) Å, respectively, and the FBiF angle is 175.1(5)°. 相似文献