ON THE PURIFICATION OF BETA-NAPHTHALENESULFONIC ACID FROM DILUTE AQUEOUS-SOLUTIONS CONTAINING SULFURIC-ACID

In the development of a biological process for the production of beta- naphthol starting from beta-naphthalenesulfonic acid, the purification of the acid from dilute aqueous solutions containing sulfuric acid is of relevant importance. We investigate the feasibility of carrying ou t such a purification using the secondary amine Amberlite LA-2 dissolv ed in toluene. Experimental measurements were performed with aqueous s olutions of beta-naphthalenesulfonic acid (NSA) in the concentration r ange 0.01-0.5 m. The organic phase comprised 0.5 m of Amberlite in the diluent toluene. Experimental results were modeled to determine the N ernst distribution coefficients of NSA and sulfuric acid and the infin ite dilution selectivity. The obtained value of this last parameter sh ows that separation is thermodynamically favored.