METHOD OF CONCENTRATING PYROGALLOL FROM AQUEOUS SOLUTIONS Russian patent published in 2015 - IPC C07C39/10 C07C37/82 

FIELD: chemistry.

SUBSTANCE: method includes extraction-sorption concentration of pyrogallol with a foam polyurethane sorbent modified with tributyl phosphate, wherein the method includes selecting, from a sheet of elastic foam polyurethane, pellets weighing 0.050±0.001 g using a metal puncher; soaking the pellets for 40 minute with a solution of tributyl phosphate in hexane; drying between layers of filter paper and holding in a drying cabinet until achieving constant weight; wherein the weight ratio of tributyl phosphate with respect to the mass (g) of the foam polyurethane varies in the ratio of elastic foam polyurethane to tributyl phosphate of 1:(0.50-0.75), in 20 cm³ aqueous pyrogallol solution acidified to pH 2-3; adding a tributyl phosphate-modified pellet of elastic foam polyurethane; shaking on a vibromixer for 15 minutes until establishing phase equilibrium; and after phase separation, collecting the equilibrium aqueous solution in which content of pyrogallol is determined photometrically through reaction with diazotised sulphanilic acid; optical density is measured on photoelectric colorimeter KFK-2 at wavelength λ=400 nm; the extraction concentration coefficient of the pyrogallol is calculated using the formula m=m_aq/m_TBP, where m_aq and m_TBP are the mass of the aqueous phase and the mass of tributyl phosphate, respectively.

EFFECT: method increases the concentration coefficient of pyrogallol and the degree of extraction thereof, while reducing consumption of the organic solvent.

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