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).