Economical, food-safe extraction of bisphenols

A method for extracting a bisphenol from a polymer substrate comprising:

• contacting the polymer substrate with an aqueous composition comprising a phase transfer agent and a base, whereby the bisphenol is extracted in to the aqueous composition;
• wherein:
• the phase transfer agent is a quaternary organic ammonium compound of Formula I:
• R1, R2, R3, and R4 may be the same or different and are independently selected from H, C1-C20 alkyl, C3-C8 cycloalkyl, heterocyclyl, C6-C10 aryl and heteroaryl groups, or R1 and R2 or R1-R3 together with the nitrogen atom to which they are bound are a part of heterocyclic ring system and at least one of R1, R2, R3, and R4 is a C6-C10 aryl or heteroaryl group;
• and
• X- represents an anion comprising halide, hydroxide, sulphonate, phosphate, alkylphosphate, dialkylphosphate, borate, alkylborate, nitrite, nitrate, carbonate, bicarbonate, alkanoate, or O,O-dialkyldithiophosphate.