Chromatographic Separation of Cardanol and Cardol

For the recovery of anacardic add, natural CNSL is required since technical CNSL only contains traces of this phenolic acid. Precipitation of its metal salts constitutes the most spedfic method, a procedure which was indeed used by the first investigator of the composition of the natural product (ref. 195). For convenience, ice-cold dilute nitric add can be used for the regeneration stage provided adequate cooling is maintained. Lead nitrate rather than the insoluble sulphate is then formed. 4-Toluenesulphonic acid is an alternative add for use in this method. 

With modifications, the phase separation method method has an application in the recovery of anacardic add from natural CNSL to avoid metal salt precipitation procedures. 

The sap from Rhus vemicifera by extraction with light petroleum affords urushiol a mixture which is considerably more sensitive to oxidative deterioration and polymerisation than the cashew phenols since it is both a catechol and even more highly unsaturated. The composition of the sap is to some extent dependent on the source but typically it contains urushiol (55-65%), water (20-30%), glycoprotein (2-3%), polysaccharides (5-7%) and laccase (-c 1%) (ref. 196 ). 

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