This separation and purification of salicylic acid, for technical field on the basis of an aqueous solution of its sodium salt

摘要

Essentially pure salicylic acid crystals, typically containing less than 0.01% inorganic salt, less than 0.01% para-hydroxybenzoic and 4-hydroxyisophthalic acid and well adopted for foodstuff and pharmaceutical applications, are facilely recovered from an aqueous solution of sodium salicylate by (i) adding an organic solvent for salicylic acid to such aqueous solution, in an amount sufficient to dissolve the salicylic acid corresponding to said sodium salt thereof, (ii) next adding thereto an at least stoichiometric amount, relative to said sodium salicylate, of a strong inorganic acid, and (iii) separating therefrom an essentially organic phase which comprises said salicylic acid and an aqueous phase which comprises an inorganic sodium salt.