Process for isolation of cardanol from technical cashew (Anacardium occidentale L.) nut shell liquid

Commercially available technical cashew (Anacardium occidentale L.) nut shell liquid (CNSL) contains mainly cardanol (decarboxylated anacardic acid) and cardol. Cardanol, the monophenolic component of technical CNSL, is widely used as a synthon for the preparation of a number of polymers and agricultural products. This paper describes the separation of cardanol from toxic cardol. Technical CNSL was dissolved in a mixture of methanol and ammonium hydroxide (8:5) and extracted with hexane to obtain cardanol. The resultant methanolic ammonia layer was extracted with a mixture of ethyl acetate and hexane to yield cardol. This is the first industrially-feasible process based on solvent extractions for the isolation of cardanol from technical CNSL.