Salicylic acid separation from other phenols

Salicylic acid may be separated from other phenols by its solubility in sodium bicarbonate solution, phenols being extracted by organic solvents from this medium. 

In aspirin, the acid catalysis is enhanced by the presence of an intra-molecular hydrogen bond. The H-bond in the salicylate anion is worth 17-21 kJ mol and raises the of the phenolic OH to 13. Other molecular models showed that EMs for intra-molecular general acid-base catalysis can be at least 10" M, if favourable intra-molecular H-bonds are formed [10]. This is also the factor that separates the typical pre-exponential factor of a bimolecular reaction in solution, 10 M sec from that of an intra-molecular reaction between the hydrogen-bonded reactants, 10 sec The basis for this change has been discussed in the context of the intersecting-state model (ISM) applications to proton transfers... 

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