Dahlund, Mats; Olin, Aake published the artcile< Chemical equilibria in aqueous solutions of olsalazine, 3,3'-azo-bis(6-hydroxybenzoic acid)>, Quality Control of 6054-98-4, the main research area is olsalazine chem equilibrium; azodisalicylate chem equilibrium; acidity azodisalicylate.
The protolytic reactions of olsalazine (I) were studied by solubility and spectrophotometric measurements at 25°. The I di-Na salt is the active component in a new drug against ulcerative colitis. The carboxylic acidity constants are pKa1 = 2.07 and pKa2 = 2.85 (0.1M NaCl) and the phenolic constants are pKa3 = 11.00 and pKa4 = 11.99 (0.25M NaCl). The solubility of H4A is 3.8 . 10-8M (0.1M NaCl). Two Na salts of the acid were studied. The solubility of NaH3A is moderate and can be calculated from its solubility product defined as Ks = [Na+][H+][H2A2-] = 1.7 x 10-10 M3. At total concentrations exceeding about 1 x 10-3 M, H2A2- starts to aggregate to form a dimer and also higher polymers. Diagrams are included to show the distribution of the I species as a function of log[H+] and total concentration, as well as the stability ranges of the solid phases.
Acta Pharmaceutica Suecica published new progress about Acidity. 6054-98-4 belongs to class alcohols-buliding-blocks, and the molecular formula is C14H8N2Na2O6, Quality Control of 6054-98-4.
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts