Which azo dyes are banned?

The European Union (EU) and the state of California (Proposition 65) have banned a number of aromatic amines that have been classified as carcinogenic. These aromatic amines can be liberated when their parent azo dyes undergo cleavage due to a raised pH (e.g. from perspiration).

What chemicals are in azo dyes?

Azo dyes are synthetic compounds containing an azo bond –N=N-, obtained mainly from the aromatic amine substrate, nitro and nitroso. The synthesis processes rely on the use of an appropriate oxidizing/reducing reaction or a diazotization/coupling reaction.

What is an azo pigment?

Organic pigments include azo pigments, which contain a nitrogen group; they account for most of the organic red, orange, and yellow pigments. Copper phthalocyanines provide brilliant, strong blues and greens that are unusually colourfast for organic colours.

Are azo dyes Banned in the USA?

Are azo dyes banned in the United States? In the United States, there are no specific regulations that explicitly restrict “azo dyes”. Instead, various aromatic amines that cleaved from azo dyes are restricted or banned.

Which azo dyes are carcinogenic?

According to current EU regulations, azo dyes based on benzidine, 3,3′-dimethoxybenzidine and 3,3′-dimethylbenzidine have been classified as carcinogens of category 2 as “substances which should be regarded as if they are carcinogenic to man”.

Who uses azo dyes?

Azo dyes are widely used in textile, fiber, cosmetic, leather, paint and printing industries. Besides their characteristic coloring function, azo compounds are reported as antibacterial, antiviral, antifungal and cytotoxic agents.

Is azo dye harmful?

Approximately 4- 5% of Azo dyes can cleave to form compounds known as aromatic amines, which are potentially dangerous to human health and have therefore been regulated. They are considered to be dangerous as there has been a relation found between these aromatic amines and cancers.

Are azo dyes safe to use?

Safety and regulation Many azo pigments are non-toxic, although some, such as dinitroaniline orange, ortho-nitroaniline orange, or pigment orange 1, 2, and 5 are mutagenic and carcinogenic. Azo dyes derived from benzidine are carcinogens; exposure to them has classically been associated with bladder cancer.

What is azo dye used for?

Azo dyes are widely used to treat textiles, leather articles, and some foods. Chemically related to azo dyes are azo pigments, which are insoluble in water and other solvents.

Why are azo compounds colored?

Azo compounds are colored due to the presence of double and triple bonds in addition to conjugation.

Why is azo dye water so insoluble?

Azoic coupling components are insoluble in water. To make them soluble in water the textile materials are impregnated in a solution of Napthol and NaOH. As the first coupling component is Napthol color. Azoic dyes contain Azo group and final color is insoluble in water, so it is called Aoic Pigment.

Are all azo dyes carcinogenic?

About 20 of the 300 known azo dyes, mostly consisting of a benzidine-based chemical, are listed as carcinogens because they are known to break down into compounds called aromatic amines.