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131.
132.
Protolytic equilibria of hydroxyxanthene dyes, Fluorescein, Eosin, as well as of some relatedcompounds, in ethanol were studied by spectrophotometry. Stepwise ionization and tautomeric equilibriumconstants were determined.  相似文献   
133.
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135.
The procedure for studying the nonuniformity of filtration flows in capillary-porous media was developed. Time dependences of local filtration coefficients averaged over the area and their spatial variation during the flow of water and aqueous electrolyte solutions were studied on soil samples of undisturbed structure using tracer method. It was found that the transformation of a pore space structure accompanied with reverse variations in pore sizes occurs because of the action of disjoining pressure in thin films depending on the ion nature. Relaxation times corresponding to the times necessary to attain equilibrium within interlayer gaps of clay minerals were determined. The conclusion was made that if the system volume is constant, the variations in the pore space structure take place because of decrease in the relative fraction of macropores and their sizes.  相似文献   
136.
137.
Inner-sphere replacement of alcohols by imidazole and its derivatives in the complex (acetato)-(tetraphenylporphyrinato)chromium(III) was studied by electronic absorption spectroscopy. The rate constants and activation parameters of the process were calculated. The entering ligand structure was shown to affect the reaction rate, while the alcohol nature (departing ligand) does not influence the kinetic parameters of the process to an appreciable extent. Regression analysis revealed participation of imidazole and ethanol in the rate-determining stages. The kinetic equation for the inner-sphere axial substitution implies interaction of a free alcohol molecule with that coordinated to chromium, followed by replacement of the associate by the heteroring. Mathematical processing of the kinetic data in terms of the proposed solvolytic association-dissociation mechanism gave the rate constants for particular stages of the process and showed an extremal relation between the rate constant and composition of the solvent.  相似文献   
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139.
Reaction of phenyl-ß-naphthylamines with formaldehyde and acetone in the presence of HCl and nitrobenzene in butanol solution leads to cyclization involving the naphthalene and phenyl rings, and formation of N-aryllepidine salts. 15 lepidine and 5, 6-benzoepidine salts are synthesized and characterized by their UV absorption spectra, as well as by their picrates.For Part LIII see [3].  相似文献   
140.
The reaction of carboxymethyl polysaccharides and their ethyl esters with amines was studied with the aim to determine how the structure of the polymeric acylating agent affects the composition of the reaction products.  相似文献   
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