Effect of Alkali Metal Cation on Copolymerization of Acrylamide with Salts of 2-Acrylamido-2-methylpropanesulfonic Acid in Aqueous Solutions

The kinetics of radical copolymerization of acrylamide with lithium, sodium, and potassium 2-acrylamido-2-methylpropanesulfonates in concentrated aqueous solutions in the presence of potassium persulfate as initiating agent at pH 9 and 50°C was studied by dilatometry.     

Degradation of Metal 2-Acrylamido-2-methylpropanesulfonate-N-Vinylpyrrolidine Copolymers in Aqueous Solutions Containing Different Cations

The influence of single- and double-charged cations on degradation of metal 2-acrylamido-2-methylpropanesulfonate-N-vinylpyrrolidine copolymers in aqueous solutions in the presence of potassium peroxodisulfate, K₂S₂O₈, at 50 and 70°C was studied by viscosimetry.     

Effect of Low-Molecular-Weight Cationic Praestols on the Efficiency of Water Pretreatment at Heat and Electric Power Plants

The efficiency of water pretreatment at heat and electric power plants using low-molecular-weight cationic Praestols (coagulants) in combination with lime, iron sulfate, and flocculant (high-molecular-weight anionic Praestol) was studied.     

Copolymerization of acrylamide with sodium 2-acrylamido-2-methylpropanesulfonate in aqueous-alcoholic solutions

The effect of solvents on the kinetics of synthesis and molecular properties of copolymers formed by radical copolymerization of acrylamide with sodium 2-acrylamido-2-methylpropanesulfonate in water and in methanol-water (75: 25, 50: 50, 25: 75), ethanol-water (50: 50), and isopropanol-water (50: 50) solutions in the presence of potassium persulfate initiating agent at pH 9 and 60°C was studied.     

The preparation of chloroplatinic acid labelled with platinum radioisotopes

A procedure has been worked out for the preparation of chloroplatinic acid from natural metallic platinum irradiated in a nuclear reactor and purified from¹⁹⁹Au impurities by extraction from acidic solutions with ethyl acetate. It was shown that the effective K X-ray activity of natural platinum on irradiation with moderate neutron fluxes /3×10¹³/ was comparable with that of^195mPt obtained from 100%¹⁹⁴Pt/with identical neutron fluxes/. Contaminations from¹⁹³Pt /50 years/ is insignificant and do not produce noticeable radiation loads on the organism on medical tests in vivo.     

Synthesis and crystal structure of (S)-pindolol

Racemic 3-(4-indolyloxy)-1,2-propanediol 2 has been effectively resolved into (S)- and (R)-enantiomers by a preferential crystallization procedure. Non-racemic (S)-2 was converted into (S)-4-(2,3-epoxypropoxy)-1H-indole (S)-4 via a Mitsunobu reaction and then into (S)-pindolol (S)-1. The crystalline (S)-1 was studied by single crystal X-ray diffraction. A large number of symmetry independent molecules (Z′ = 6) led to a weakening of the system of strong intermolecular hydrogen bonds, which combined with a loose packing (PI = 64.6%), may be the cause of the abnormally low melting point of (S)-1 as compared with rac-1.     

Heterogeneous copolymerization of acrylamide with maleic acid in dioxane

Heterogeneous copolymerization of acrylamide with maleic acid has been investigated. The process was carried out at 70°C in 1,4-dioxane. The polarographic method of analysis was applied. The analysis of the experimental and theoretical composition distribution curves has shown an anomalously large composition polydispersion for the experimental distribution curves. This is attributed to the heterogeneity of the copolymerization process.     

Modelling Turbulent Premixed Combustion Using the Level Set Approach for Reynolds Averaged Models

A model for premixed turbulent combustion is investigated using a RANS-approach. The evolution of the flame front is described in terms of the G-equation. The numerical instabilities of the G-field are resolved using a reinitialisation procedure. For the G-points near the flame surface an algorithm proposed by Russo and Smereka [1] and modificated by Düsing [2] is presented. For all other points the standard Sussman algorithm is employed. Fluid properties are conditioned on the flame front position using a burnt-unburnt probability function across the flame front. Computations are performed using the code FASTEST-3D [3] which is a flow solver for a non-orthogonal, block-structured grid. The computational examples include two test cases, the first containing the propagation of two circular merging flames and the second one containing the simulation of the ORACLES-burner [4].     

Radical copolymerization of sodium 2-acrylamido-2-methylpropane sulfonate and sodium acrylate in water-alcohol solutions

The effect of the nature of a solvent on the kinetic parameters of the process and the intrinsic viscosities of copolymers formed by the homogeneous free-radical copolymerization of the sodium salt of 2-acrylamido-2-methylpropane sulfonic acid and the sodium salt of acrylic acid initiated by potassium persulfate in water, water-methanol mixtures (92: 8, 84: 16, 75: 25, 50: 50), and water-isopropanol (50: 50) mixtures at pH 9 and 60°C is studied. The initial rate of copolymerization increases with increases in the concentrations of the comonomers and initiator, the content of 2-acrylamido-2-methylpropane sulfonic acid in the initial monomer mixture, and the content of water in a water-methanol mixture and in the sequence of solvents water-methanol < water-isopropanol. The intrinsic viscosity and yield of the copolymer grow when the content of 2-acrylamido-2-methylpropane sulfonic acid in the initial monomer mixture and water in water-methanol mixtures are increased and when isopropanol is replaced with methanol. The reactivity ratios of the monomers in water-methanol (50: 50) and water-isopropanol (50: 50) mixtures are determined.     

Evolution of the Structure of Aluminosilicate Particles in the Course of Formation of Nanocomposite Coatings Based on Alkyd Oligomers

Russian Journal of Applied Chemistry - Various steps of the formation of nanocomposite coatings using organic-soluble film-forming agents are accompanied by changes in the structure of the...