Patent ID: 11919837
Assignee: KING FAISAL UNIVERSITY
Field: Organic fine chemistry (Chemistry)
Classification: CPC C  A | IPC A  C

Claim 3:
4. A method of making the 4,4′-naphthalene-1,5-diylbis(diazene-2,1-diyl)dinaphthalen-1-ol compound of claim 1, the method comprising:
adding a cooled solution of sodium nitrite in water to a cooled solution of naphthalene-1,5-diamine and hydrochloric acid with stirring to obtain a cooled diazonium salt solution;
adding the cooled diazonium salt solution to a cooled solution of 1-naphthol in sodium hydroxide to obtain an azo dye precipitate;
filtering and recrystalling the azo dye precipitate using ethanol; and
obtaining the 4,4′-naphthalene-1,5-diylbis(diazene-2,1-diyl)dinaphthalen-1-ol compound.