METHOD OF EXTRACTING CAFFEINE FROM AQUEOUS SOLUTION Russian patent published in 2013 - IPC G01N33/15 B01D11/04 G01N21/33 

FIELD: chemistry.

SUBSTANCE: to extract caffeine from an aqueous solution, a water-salt solution of caffeine with pH 11.0±1.0 is prepared using saturated potassium carbonate solution as a salting-out agent; caffeine is extracted until establishment of phase equilibrium for 7-10 minutes with a solution of a solvotropic reagent in ethyl alcohol with concentration of 0.85-0.90 mol/dm³ with volume ratio of the water-salt solution of caffeine to the extractant of 5:1; the water-salt phase is separated from the organic phase and analysed by UV spectrophotometry at wavelength of 272 nm. Concentration of caffeine in the aqueous solution is determined from a calibrated curve.

EFFECT: method enables to achieve high coefficient of distribution of caffeine with one-fold extraction with a solution of a solvotropic reagent in ethyl alcohol, and virtually complete extraction of caffeine from the water-salt solution.

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