Preparation of Sodium 2'-Hydroxy-4'-alkoxybenzophenonesulfonates and Their Physico-chemical, Antiphotofading Properties

Abstract

Sodium 2'-hydroxy-4'-alkoxybenzophenonesulfonates (alkyl: n-C₈H₁₇, R8;n-C₁₂H₂₅, R12;n-C₁₆H₃₃, R16) were prepared and identified by elemental and instrumental analysis. Studies on the physico-chemical properties were carried out on aqueous solutions of these samples. From these results, it was found that R 12 and R 16 were fairly active in surface tension depression, as well as in emulsification of liquid paraffin and solubilization of Orange OT into water. Studies on the photofading of Congo Red in the presence of the above samples in aqueous solution were also carried out. Photodegradation of Congo Red occurred as the results of irradiation by a Hg lamp to aqueous Congo Red solution, and the changes of concentrations of Congo Red with elapsed time were measured by spectrophotometric (UV) method.
Decreasement of comparative specially fixed absorption of Congo Red in the aq. solution of salts of 1-naphthol-4-sulfonic acid, naphthionic acid and above 4 samples addition were compared at the same conditions. Above all, naphthionic acid was the most effective, as it seems that this result was caused by the similar chemical structure between substrate and the additive. The ability of 4 samples as retarder against photofading of Congo Red was as follows: R 4>R 8>R 16>R 12.