CI 42051 is a salt of [4-(4-diethylaminophenyl)-5-hydroxy-2,4-disulfophenylmethylidene] diethylammonium hydroxide, which can be sodium or calcium based. It functions as a cosmetic colorant in personal care products. It is a dark bluish dye that imparts a greenish blue shade.
What is CI 42051 used for?
CI 42051 is used as a colorant in cosmetics of the skin, hair, and nails, and in the preparation of creams, shampoos, etc. It ensures that cosmetic products have a pleasing appearance and enhances the appearance of the skin and hair. It is also used in dental disclosing tablets as a stain to show the dental plaque on teeth. Its color is dependent on the pH. In an aqueous solution, its color may vary from a deep blue in alkaline or weekly acidic medium to a yellow-orange in stronger acidic conditions.
Origin
3-Nitrobenzaldehyde and N,N-dimethylbenzeneamine are condensed, then reduced, then the amino diazotization takes place and a hydroxyl compound is formed, and finally a sulphonation reaction is carride out to produce a calcium salt followed by segregation and oxidation.
Safety profile
CI 42051 is subject to restrictions in Europe, IV/60, II/1356, and the dye must respect the purity criteria defined in directive 95/45/EC of the Commission (E 131). It is not recommended for children in Australia and the US as it could trigger allergic reactions, nausea, itching, and, in rare instances, anaphylactic shock in children.