Search academic texts

Information × Registration Number 0207U004740, 0104U000660 , R & D reports Title Acidity, solvation,and assotiation in organized solution,microreactors and nanochemical object popup.stage_title Head Mchedlov-Petrosyan Nikolai Otarovich, Registration Date 14-08-2007 Organization Kharkov national university named after V.N. Karazin popup.description2 The objects of research are reaction media of both new type, i.e., direct microemulsions and solutions of cyclodextrins and calixarenes, and traditional ones, such as water-organic mixtures, as well as indicator dyes of various nature. The aim of the study was to reveal regularities of the influence of reaction media, in particular, of organized solutions, microreactors, water-organic mixtures, on the protolytic and related equilibria, on spectral and thermodynamic properties of organic reagents, and to develop approaches for prediction of such influence. Methods of research: potentiometry, spectrophotometry, fluorometry, 1H NMR spectroscopy, gravimetry. The equilibria of two fluorescein dyes in reversed AOT-stabilized microemulsions were studied. It was revealed that the and values of fluorescein essentially approach each other. For comparison, the equilibria of hydroxyxanthenes in the ternary mixture ethanol - benzene - water (mass ratio 47 : 47 : 6) were studied. The differentiating action of the given ternary mixture is caused by possibilities of selective solvation of dye molecules. The indices of 'apparent' ionization constants values, , of rhodamine derivatives were determined vis-spectroscopically, with potentiometric pH measurements, in micellar solutions of colloidal surfactants, in mixed micellar solutions, and in microemulsions. The photophysical properties of aminoxanthene dyes in micellar solutions of ionic surfactants were examined. The values of electrostatic interfacial potential of ionic micelles were estimated. The values of phenolphthalein and thymolphthalein were determined in aqueous solutions of ?-cyclodextrin. In this system, the and values are ill resolved. Likewise, these values strongly approach each other in suspenzions of phospholipids, sodium dodecylsulfate micellar solutions, and microemulsions. The solubilities of N-cetylpyridinium and cetyltrimethylammonium perchlorates in water-acetone system were determined within the range of 278.15 - 308.15 К. The solubilityproducts, thermodynamic functions of solubility and of transfer from water to the corresponding solvents were evaluated. The association of N-cetylpyridinium and cetyltrimethylammonium cations with perchlorate anion in 1-butanol and water-acetone mixtures was studied using conductance method. The association constants, limiting molar conductivities, and the parameters of closest approach were evaluated. The association of Reichardt's dyes with Li+ ions was studied in DMSO as solvent. The association constant is calculated, the spectrum of the associate is singled out. The protolytic equilibria of hydroxyxanthene dyes in direct microemulsions were studied at bulk ionic strength of 1 mol dm-3. The main regularities of medium effects on protolytic equilibria of the aforesaid dyes were revealed. The equilibria of thiofluorescein and thioeosin were studied in water-ethanol and water-acetone mixtures of varying content. It was demonstrated that the monoanion of thioeosin, contrary to that of thiofluorescein, existsas a structure with dissociated hydroxy group and undissociated carboxylic group. The spectral and acid-base properties of a set of sulfonephthalein dyes were studied in aqueous solutions containing tetraammonium-calix[4]arene. The analysis of the 'apparent' values allowed to conclude that the acid-base and spectral properties of the dyes in the presence of cationic calixarene are similar to those in micellar solutions of colloidal cationic surfactants. The solubility of cetyl-trimethylammonium perchlorate in water - 2-propanol system was studied within the temperature range of 278.15-308.15 К. The mean-ionic activity coefficients, , were calculated for saturated solutions. The solubility products, standard thermodynamic characteristics of cetyl-trimethylammonium perchlorate, as well as standard thermodynamic transfer characteristics of the mixture of С16Н33N(СН3)3+ and ClO4? ions from water into the solvents studied were determined. The complexes of rhodamine 200 B were studied in organic solvents of different nature. The vis absorption and emission spectra were obtained. The association constants of dye anion with organic cations were calculated from conductivity data. The influence of small additives of dimethyl sulfoxide and water on electromotive force of cells with liquid junction with quinhydrone electrode were studied in HCl and picrate buffer solution in acetone. The association of solvatochromic Reichardt's betaines with lantanoid-shifting reagent Eu(DPM)3 was studied in deuterochloroform using NMR spectroscopy. It was demonstrated that the association occurs with the phenolate oxygen atom. The protolytic equilibria of hydroxyxanthene dyes were studied in direct microemulsions. The indices of the 'apparent' dissociation constants of fluorescein and 2,7-dichlorofluorescein were determined in reverse microemulsions of water-in-oil type stabilized with Aerosol OT. Eleven betaine indicators were studied in direct microemulsions. It was demonstrated that in these systems the pseudophase model works satisfactorily, and application of the 'apparent' constants concept was confirmed. The interaction of three derivatives of 4-(2,4,6-triphenylpyridinium-1)-phenolate with Na+, Mg2+, and La3+ ions as well as with organic acids in n-butanol and DMSO were determined with the help of Vis spectroscopy.The ionic equilibria of methyl orange were studied in the presence of droplets of microemulsions at constant ionic strength and various volume fractions of organic phase; the 'apparent' dissociation constants and partition constants of acid-base couple of the dye were obtained. The protolytic equilibria of dyes in aqueous solutions of calyx[4]arenes and ?-cyclodextrin were studied and the 'apparent' dissociation constants of indicator dyes were determined in these media by using Vis ectroscopy. The results obtained can be recommended for physical chemistry, colloid chemistry, biology and biochemistry, photo- and analytical chemistry, as well as in academic courses of physical and colloid chemistry. Product Description popup.authors popup.nrat_date 2020-04-02 Close