solubility

Based on the temperature dependence of the solubility of 5-(2-nitrophenyl)-furan-2-carboxylic acid, 5-(3-nitrophenyl)-furan-2-carboxylic acid and 5-(4-nitrophenyl)-furan-2-carboxylic acid in propan-2-ol, the enthalpy and entropy of their dissolution were calculated. Taking into account the enthalpy and entropy of melting recalculated to 298 K, the enthalpies and entropies of mixing were calculated. The dependence of the solubility of carboxyl-containing substances at 298 K on their melting point was determined.

The Fe3O4 nanoparticles dissolution in the acid media (pH = 1.8–5.0; 3 h) has been studied. The kinetic curves have been obtained and Fe3О4 solubility has been determined using spectrochemical, gravimetric and atomic absorption methods. Fe3О4 solubility was found to be increased with the increase in inorganic media acidity and the time. By means of SEM, XRD and NMR analyses the effect of acidic media on the physico-chemical properties of Fe3О4 particles surface has been determined.

In this study solubility of racemic (R/S)(±)-ibuprofen in pure conventional solvents (n-heptane, toluene, benzene and ethanol) and supercritical carbon dioxide is predicted and the results are compared with experimental data. The results of the ideal solubility show great deviation from experimental points. However, it seems that liquid phase non-ideality is the main problem in the modeling of this system. To capture the non-ideality of the system UNIQUAC, UNIFAC, NRTL, Wilson, and regular-solution theory are used.

Hydrogen sulfide gases are formed in many technological processes, in particular, the processing of natural combustible fossil fuels. During the purification of coke oven gas containing cyanadium, from hydrogen sulfide by arsenic-sodic method, sodium thiocyanate is formed together with thiosulfate. Polymer sulfur, which is formed because of the acid decomposition of sodium thiosulfate, contains slightly soluble impurities. They aggravate its rheological properties and cause excessive high ash content of polymer sulfur up to 8%.

Chitosan films were obtained in the salt form and in the hydroxide form. Films were prepared by dry method of forming. For the production of films chitosan from mycelium biomass waste of fungus Aspergillus Niger was used. The effect of heat treatment on the structure and solubility of chitosan films was studied. It was established that during the heat treatment of the films the process of amidation takes place, which in turn leads to the structure ordering and reduces the solubility of the films.

Synthesis of poly(o-anisidine) with and without acrylic acid doping is carried out by chemical oxidative polymerization method. This is a new polymerization method for the direct synthesis of the emeraldine salt of poly(o-anisidine), i.e. it is directly soluble in known organic solvent such as m-cresol, N-methyl pyrrolidone (NMP), DMSO, DMF, etc. without the need for a conversion of salt phase to base form.

Polydiphenylamine (PDPA) doped with acrylic acid was synthesized by oxidative chemical polymerization. This is a new chemical polymerization method developed for the direct synthesis of emeraldine salt form of polydiphenylamine which exhibits remarkably improved solubility in a common organic solvent. These polymers have been characterized by the physical techniques such as UV-visible, FTIR, XRD and conductivity measurement. The results are discussed with reference to the H2SO4 doped polydiphenylamine.

Poly(o-toluidine) doped with acrylic acid and without it was synthesized by using chemical oxidative polymerization technique. With the help of this method the polymer, poly(o-toluidine) was synthesized in the form of emeraldine salt. The oxidizing agent used for this method is the ammonium persulphate .The polymer products were characterized by UV-Visible and FTIR spectroscopy. The polymer, poly(o-toluidine) doped with acrylic acid was highly soluble in common organic solvents like m-cresol, NMP, DMF etc.

The article deals with the investigation results of nitrogen-containing compounds solubility in non-polar and polar solvents, as well as low-temperature properties of formed solutions and their anticorrosive properties as corrosion inhibitors in the hydrocarbon-water two-phase system.

Emeraldin salt of polyaniline was synthesized by chemical oxidative polymerization method; this salt is soluble in common organic solvents. The obtained results are discussed with reference to lactic acid doped polyaniline. It has been observed that acrylic acid doped polyaniline is comparatively more soluble than polyaniline doped with lactic acid in common organic solvent such as m-cresol, NMP (N-methyl pyrrolidinone), DMSO, DMF, etc. The acrylic acid doped polymer prepared using lactic acid is comparatively more soluble in m-cresol and NMP than the polyaniline without acrylic acid.