Fast,easy, and efficient method for the purification of phenolic isomers using a selective solid-phase scavenging process

The need for fast and efficient purification methods that can be easily handled and moreover automated is considerably increasing with the new techniques of high-throughput chemical synthesis. Following our previous work on the use of simple polymeric scavengers in fast reactions and purifications of organic substances, this article presents the results found during the development of a new method for the purification of phenolic substances. The purification method was found to be regulated by the interaction of acidic phenol groups with a basic polystyrene resin. Furthermore, the scavenging of phenolic isomers proved to be very selective for a given isomer. But the most interesting aspect of this method is that it is based on a simple contact in situ with the resin and that the adsorption/desorption process of the phenol was found to be solvent-dependent. The phenols can thus be freed from impurities, or other isomers, by a simple and fast contact with the resin in the first solvent, filtration, and washings, followed by liberation of the purified phenol by a last soaking in another solvent for desorption. The method was successfully applied to the purification of a crude reaction mixture issued from the Fries rearrangement of phenyl acetate, as well as to small libraries of phenolic derivatives.