P. T. Sukhanov

The distribution coefficients of phenol and substituted phenols in the ammonium sulfate-poly-N-vinylpyrrolidone-water system

The extraction of phenols from water-salt solutions was performed using a water-soluble polymer (poly-N-vinylpyrrolidone). The distribution coefficients, the degree of extraction of 13 phenols, and interrelation between the extraction characteristics and structure of distributed compounds were determined. The conditions of the process were optimized to provide maximum extraction of phenols by poly-N-vinylpyrrolidone from water-salt solutions.

Effective systems based on hydrophilic polymers for extraction of phenols from aqueous solutions

Water-soluble polymers (poly-N-vinylpyrrolidone, poly-N-vinylcaprolactam, polyethylene glycol) were used for the first time for extraction of phenols from aqueous solutions. The influence exerted by pH of the aqueous solution and kind of the polymer on the degree of recovery of phenol and some of its methyl and nitro derivatives was elucidated. The correlation between the structure and extraction characteristics of phenols was interpreted.

Extraction-chromatographic determination of sulfonated azo dyes in aqueous solutions

The extraction of sulfonated azo dyes E102, E110, E122, E124, and E129 from aqueous solutions using hydrophilic solvents and their mixtures in the presence of a salting-out agent (ammonium sulphate) has been studied. Some regularities of extraction have been revealed. The composition of the mobile phase has been optimized and a procedure has been proposed for the identification and determination of the dyes in aqueous solutions by thin-layer chromatography in concentrations of 0.1–0.01 μg/L. An office scanner and a personal computer have been used to process the results of the separate determination of the dyes.

Extraction Preconcentration of Naphthols and Phenol with Solvent Mixtures Impregnated into Polyurethane Foam

The extraction of phenol and naphthols with isomolar mixtures of nonane and tributyl phosphate, dibutyl phthalate, or hexane impregnated in ester-based polyurethane foam was studied. The optimum conditions for the extraction–adsorption preconcentration (equilibration time, the pH of the solution, the volume of the test sample, the mass of the adsorbent pellet, and the nature and composition of the mixture applied to polyurethane foam) were determined. A procedure providing the 250- to 350-fold preconcentration of phenol and naphthols is proposed for quantitative extraction.

Two-Stage Extraction Preconcentration and HPLC Determination of Phenol and 1-Naphthol in Aqueous Solutions

The extraction of phenol and 1-naphthol with isomolar mixtures of ethyl acetate and hexane under batch conditions and with tributyl phosphate impregnated into a polyurethane foam under batch and dynamic conditions was studied. A procedure for determining phenol and 1-naphthol in aqueous samples was developed including their dynamic recovery on a column packed with polyurethane foam impregnated with tributyl phosphate, elution with a 0.1 M NaCl solution of pH 12.5–13.0, extraction with a mixture of ethyl acetate and hexane, and separation by normal-phase high-performance liquid chromatography (HPLC) with UV-detection. The overall preconcentration coefficient was 250. The detection limits were 2.5 μg/L. The relative error of determination was lower than 18%. The time of one determination was 2–2.5 h.

Recovery of anthocyan dye from aqueous-salt solutions with polyethylene glycol PEG-5000

Extraction with PEG-5000 was studied as a method for recovering and concentrating a natural anthocyan dye from sodium and ammonium sulfate solutions. The effects of the type of salt cation, pH, and addition of aliphatic alcohols on the dye recovery were examined.

Extraction-chromatographic determination of hydroxysulfo compounds

Conditions of the extraction of naphtholsulfonic acids and azo dyes with an acetone-diacetone alcohol mixture from a saturated solution of ammonium sulfate in the presence of N-cetylpyridinium chloride were optimized. A procedure was developed for the determination of naphtholsulfonic acids and azo dyes in the presence of naphthols on the basis of extraction with a mixture of solvents and an analysis of the concentrate by paper chromatography with elution with the same mixture in the presence of water.

Extraction of naphtholsulfonic acids from aqueous solutions with the use of a rotating concentrating unit and their photometric determination in the back extract

A new concentrating unit is proposed for the extraction of naphtholsulfonic acids; the unit is a ferromagnetic (steel) rod in a polyethylene or glass case coated with a mixture of cetyl alcohol with trioctylamine N-oxide. The rod is immersed in an analyzed solution and rotated in an alternating magnetic field (solid-phase extraction). The extraction-sorption characteristics of naphtholsulfonic acids were calculated, and a procedure was developed for their selective photometric determination in back extracts.

Extraction of Aromatic Sulfonic Acids in the Presence of a Surfactant

Extraction of phenol- and naphtholsulfonic acids from aqueous salt solutions in the presence of a surfactant, N-cetylpyridinium chloride, with hexane, ethylbenzene, and acetone-diacetone alcohol is studied.