DESCRIPTION

Sunset Yellow occurs as a brown-orange powder or granules. It is principally the disodium salt of 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalene-sulfonic acid. The trisodium salt of 3-hydroxy-4-[(4-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid may be added in small amounts. It dissolves in water to give a solution yellow-orange at neutrality or in acid and red-brown in base. When dissolved in concentrated sulfuric acid, it yields an orange solution that turns yellow when diluted with water. It is insoluble in ethanol.