Abstract
New Azo compounds containing an 1,8-naphthalimide moiety were synthesized from 1, 8-naphthalic anhydride by a reaction with p-phenylenediamine or benzidine to produce 1,8-naphthalimide derivatives (1 or 2), which were converted to diazonium salt derivatives by using sodium nitrite and acetic acid at 0-5 áµ’C. The diazonium salt was subjected to a coupling reaction with different substituted phenol in alkaline media at 0-5 áµ’c to produce azo compound derivatives (3-14).
 The New Azo compound derivatives (3-14) were identified by 1H-NMR, 13C-NMR, and FTIR and by measuring characteristic physical properties and specific reactions. Also, the ability of the prepared azo compounds to work as acid-base indicator was investigated, since azo dyes have different and sharp colors in acidic or basic solutions.
Highlights
PH indicators or acid-base indicators are halo chromic weak acids or bases which change their structures upon the pH change in solution
Some of the azo compounds have two tautomeric forms such as methyl orange and methyl red, each one has a different color and can be transformed from one form to another depending on the pH level of the environment, they are used as pHindicator
This property is very useful to detect the pH-level and was used extensively by researchers in various fields; it is employed in biological research to determine the acidity of the living media [4] and in analytical chemistry to detect the end point in acid-base titration.[5]
Summary
PH indicators or acid-base indicators are halo chromic weak acids or bases which change their structures upon the pH change in solution. -نفثال أيمايد و دراسة قابليتها كدالئل حامض-1,8 تحضير و تذخيص مركبات ازو جديدة مرتبطة بـ 1H-NMR spectrum of compound 1 showed a singlet signal of (-NH2) protons at δ= 5.28 ppm and multi signals aromatic protons at δ= 6.95-8.56 ppm, as shown in Table-2 and Figure-1.
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