JPH0261935B

A process for the extraction of aromatic (e.g., phenyl-containing) amino acids from an aqueous phase (solution) containing them, comprising combining the aqueous phase with a tenside of the formula R-U-SO3X wherein R is alkyl or cycloalkyl each of 4-18 carbon atoms; or phenyl or naphthyl, each optionally substituted by alkyl groups, and having up to 18 carbon atoms total. U is a carbon-to-sulfur bond or an oxygen atom, and X is an alkali metal ion; acidifying the aqueous phase to a pH value of 2.0-2.5; and extracting the aqueous phase with an alcohol, a ketone, or a carboxylic acid alkyl ester, each containing 4-6 carbon atoms.