Nitrosation of Dodecahydro-closo-Dodecaborate Anions in Aqueous and Nonaqueous Solutions

Nitrosation of dodecahydro-closo-dodecaborate anions with nitrous acid in an aqueous solution and with isoamyl nitrite and nitrosyl chloride in nonaqueous solutions was studied. The main reaction product is the mononitrosoundecahydro-closo-dodecaborate anion. Conditions were selected for the preparation of the nitroso-substituted anion in the highest yield as alkylammonium, tetraphenylphosphonium, and alkali-metal salts. The salts were studied using IR, UV, and ¹¹B NMR spectroscopy.     

Cluster Model of Aggregation of Epoxy-DPP Oligomers in Solutions. Structure of Coatings Based on Epoxy and Epoxy-Phenol Resins

The IR MATIR spectra in the 1535-1680 cm^-1 range were studied for epoxy-DPP resins (M _N = 1650-3400) in coatings on germanium substrate obtained from oligomer solutions in methylene chloride and Cellosolve with the concentration c = 10-50%. The concentration dependences of the relative viscosity of narrow-MWD fractions of epoxy oligomers (M _N = 1500-5300) in chloroform and Cellosolve solutions were studied. The structure of the network of cross-linked polymers based on epoxy (M _N = 2100-3400) and phenol-formaldehyde (M _N = 860) resins was studied by the electron-microscopic silver chloride decoration method. Based on the cluster lattice model, the optimal molecular weight and the concentration regimes were determined for epoxy oligomers in the lacquer composition for can protection.     

Properties of cellulose solutions in methylmorpholine N-oxide containing montmorillonite nanoparticles and of composite films thereof

Rheological properties of moderately concentrated solutions of cellulose in methylmorpholine N-oxide-dimethylformamide mixtures containing hydrophilic montmorillonite nanoparticles were studied. Film composite materials were prepared, and their physicomechanical properties and structural organization were studied.     

Reactivity of fluorostyrenes in cationic polymerization

Reactivity ratios relative for cationic copolymerization of three fluorostyrenes and styrene were studied. The values of r₁ and r₂ for various experimental conditions were determined. The influence of the nature of the solvent and of the polymerization temperature were studied in particular. Relative activation entropies and enthalpies were determined, and an isokinetic relationship was found for 2-, 3-, and 4-fluorostyrenes. There is a fairly linear correlation between the C8 chemical shift and the values of 1/r₂. All the experimental reactivities were correlated with the quantum chemistry parameters. From this correlation, interaction with C8 and also with C7 and F, was found to be possible, depending on the nature of the monomer.     

Polymerization of Styrene in the Presence of Nitroxyl Radicals Generated Directly in the Course of the Polymer Synthesis (in situ)

The features of radical polymerization of styrene in the presence of nitroxyl radicals generated directly in the course of the polymer synthesis (in situ) by irreversible reaction of stable organic compounds 2-methyl-2-nitrosopropane, C-phenyl-N-tert-butylnitrone, and nitrosodurene with propagating polymer radicals were studied.     

正辛烷为稀释剂不对称N-甲基-N-辛基烷基酰胺萃取铀(Ⅵ)的研究(英)

The extraction of uranyl nitrate was studied with newly synthesized unsymmetrical alkylamides, Nmethyl-N-octyloctylamide (MOOA), N-methyl-N-octyldecanamide (MODA), and N-methyl-N-octyldodecanamide (MODOA), employing n-octane as diluent. The effect of the concentrations of nitric acid, sodium nitrate and extractants on the extraction was investigated and the extraction mechanism was suggested. The effect of temperature on the extraction was also studied and the related thermodynamic functions were calculated. The extracted species were characterized by FTIR spectrometry。     

Anthranilic acid hydrazide in the synthesis of fused polycyclic compounds with quinazoline moieties

A modified procedure was developed for the synthesis of 5,6,7,8,13,13a-hexahydrophthalazino[1,2-b]quinazoline-5,8-dione and 6-amino-5,6,6a,11-tetrahydroisoindolo[2,1-a]quinazoline-5,11-dione from o-formylbenzoic acid and anthranilic acid hydrazide. The mechanism of the transformation is suggested, some reactions were studied, and new derivatives of these compounds were synthesized. Anthranilic acid hydrazide was used in the novel synthesis of 5-substituted phthalazino[1,2-b]quinazolin-8-one derivatives. The possible reaction mechanism is discussed. 5,6,7,8-Tetrahydrophthalazino[1,2-b]quinazoline-5,8-dione and 5-phenylphthalazino[2,1-b]quinazolin-8-one were studied by X-ray diffraction.     

Dipole Structure and Electrooptical Properties of Poly-N-vinylpyrrolydone in Nonaqueous Solvents

Electrooptical Kerr effect and dielectric polarization were studied for poly-N-vinylpyrrolidone solutions in chloroform and in mixed chloroform-CCl₄ solvent. The results were compared with those for an analogue of the monomeric unit of poly-N-vinylpyrrolidone, low-molecular-weight compound N-methylpyrrolidone.     

Liquid-Vapor Equilibrium in the Isobutanol-n-Butanol-Butyl Butenyl Ether Ternary System,Azeotropy in Butyl Alcohols-Butyl Butenyl Ether-Water Systems,and Separation of Their Components by Distillation

Liquid-vapor equilibria and azeotropy in isobutanol-n-butanol-butyl butenyl ether ternary system and in isobutanol-butyl butenyl ether and n-butanol-butyl butenyl ether binary systems were studied experimentally and calculated, as well as azeotropy in butyl alcohols-butyl butenyl ether-water systems under atmospheric and reduced pressure. Recovery of commercial butyl alcohols by distillation of alcohol-ether fractions was studied.     

Ionic Equilibria of Chromophoric Reagents in Microemulsions

Protolytic equilibria of twenty chromophoric acid–base indicators from different classes, namely, sulfophthaleins, hydroxyxanthenes, azo compounds, and others, were studied in direct microemulsions of benzene–pentanol-1–surfactant–water at volume fractions of the dispersed phase of up to 13%. Cetylpyridinium chloride, sodium dodecylsulfate, and certain nonionic surfactants were used. Apparent acidity constants (pK _a) of indicators were determined under the conditions of their complete binding by microdroplets (pK _a ^ac). The strong differentiating effect of the dispersed phase of microemulsions of different types on the acid–base properties of indicators was revealed. The effect of the ionic strength of the continuous phase (0.025–1.0) on the values of pK _a ^ac was studied. The partition constants of Bromothymol Blue anions between water and negatively charged microdroplets were estimated. Similarities and differences were revealed in the action of microemulsions and micellar solutions of the corresponding surfactants on the state of the studied chromophoric reagents.     

Properties of Flax Cellulose Solutions in Tertiary Amine N-Oxides and of Films Thereof

The solubility of flax fibers differing in the degree of purity in triethylamine N-oxide monohydrate was studied. The size and amount of the associates in equiconcentrated solutions were estimated from the turbidity spectra. Rheological properties of solutions of cotton and flax cellulose were compared. Hydrated cellulose films were obtained from solutions, and their physicomechanical properties were studied. The films were characterized by IR spectroscopy.     

Mutual Transformations of Isomers in N-Methyl-5-vinyltetrazole Copolymers

Mutual transformations of N ¹ and N ² isomeric derivatives of 5-vinyltetrazole polymers in the absence of a solvent were studied.     

Internal rotation in the molecular ions of benzoic acid and salicylic acid. An INDO molecular orbital approach

An aspect of the mechanism of the hydroxyl H/ortho H scrambling in the molecular ion of benzoic acid was studied by the open-shell INDO molecular orbital method. Energies of te unrearranged structure, the planar structure in which H is attached to carbonyl oxygen and rotational conformers of the latter were studied to determine a pathway of minimum energy for rotation. The same calculations were made for salicylic acid, m-fluorobenzoic acid and p-fluorobenzoic acid. The results of these calculations agree quite well with experimental results.     

Photochemistry of benzothiazolylformazanes in solutions

Photochemical transformations of substituted benzothiazolylformazanes were studied by electronic spectroscopy under conditions of steady-state photolysis. The phototransformations were established to be photoreversible cis—trans-isomerization, unlike photoirreversible one of triphenylformazane. Electron-donor and electron-acceptor substituents (except for NO₂) in the para-position of the phenyl ring of one of the nitrogen atoms retard thermoisomerization.     

Copolymerization of N-Vinylsuccinimide with Butyl Methacrylate in Pyridine

The kinetics of radical copolymerization of N-vinylsuccinimide with n-butyl methacrylate in pyridine was studied, and the previously unknown copolymerization constants of the monomers were determined. The calculations were performed using appropriate software and a new procedure for approximation of the experimental data, which allow determination of the kinetic parameters at high conversions with the minimum error. The copolymerization kinetics were compared for the reaction systems constituted by N-vinylsuccinimide and n-butyl methacrylate and by N-vinylsuccinimide and n-butyl acrylate.     

Influence of the Reaction Medium on the Kinetics of Copolymerization of N-Vinylsuccinimide with Butyl Acrylate

Radical copolymerization of N-vinylsuccinimide with n-butyl acrylate in pyridine and the influence of donor characteristics of the solvent on the reaction kinetics were studied. The kinetics of copolymerization in various solvents (dichloroethane, dimethyl sulfoxide, and pyridine) were studied.     

The kinetic peculiarities of intermolecular proton transfer from NH groups of octa(<Emphasis Type="Italic">m</Emphasis>-trifluoromethylphenyl)tetraazaporphin in the nitrogen base-benzene system

The acid-base interaction of octa(m-trifluoromethylphenyl)tetraazaporphin with nitrogen bases in benzene was studied. The rates of intermolecular transfer of sterically screened NH group protons from octa(m-trifluoromethylphenyl)tetraazaporphin to n-butylamine and tert-butylamine were found to be low. A scheme of the process was suggested. The influence of the nature of bases on the kinetic parameters of acid-base interactions was studied.     

Fluorescence properties of selected benzo[c]phenantridine alkaloids and studies of their interaction with CT DNA

The spectral, especially fluorescence properties, of seven selected quaternary benzo[c]phenantridine alkaloids (sanguinarine, chelerythrine, chelirubine, sanguirubine, chelilutine, sanguilutine, and macarpine) were studied in presence and in absence of double-stranded DNA. This study has proved dramatic differences in fluorescence emission of all studied alkaloids in presence of calf thymus DNA in comparison to fluorescence of free alkaloids. The most remarkable are changes in emission spectra of macarpine, chelirubine, and sanguirubine. Association constants (logK) for interaction of all studied alkaloids with CT DNA were calculated.     

Metalation of diazines. VI. Metalation of pivaloylaminopyrazine and N-t-butylpyrazinamide. Unusual regioselectivity in the metalation reaction

Metalation of pivalamidopyrazine and N-t-butylpyrazinamide were studied. For pivalamido pyrazine the yields were poor and some addition products were isolated. The metalation of t-butylpyrazinamide was successful and a curious regioselectivity was highlighted.     

Relationship of textural properties and catalytic behavior in polycrystalline ZSM-5 zeolites

Polycrystalline ZSM-5 zeolites were studied in the cracking ofn-pentane and the isomerization ofm-xylene. It was found that slow deactivation rates and lowp-selectivity are related to large external surface areas determined by the t-plot method.