Preparation and Characterization of Two Azo Dyes For Dibenzothiophen by the Diazotization Reaction and Studying Their action as Acid-Base Indicators.

This research describes the preparation of two dyes , by nitration of dibenzothiophen to form p-nitro dibenzothiophen and reduction to form p-amino dibenzothiophen , and creating by the diazonium salt that is reacted with (1&2-naphthol ) to form azo dyes . their ft.ir spectra and melting points were measured . one of these preparation dyes with orange color had been studied as an acid- base indicator by its effects in titrimetric analysis by using methods of acid – base titration . which was changed its color from colorless to orange in basic media , and from orange to colorless in acidic media . dye (p- dibenzothiophen azo-8-naphthol) was an active acid-base indicator .the color difference between two spaces was clear, and the ph range of color change was (6-10).