Azo dye

Description

A large group of synthetic dyestuffs containing one or more nitrogen double bond (azo) groups as its chromophore. Azo chromophores were first discovered in 1863 when Martius and Lightfoot coupled diazonium ions and amines. Within the year, Peter Greiss prepared Bismarck brown, the first azo dye. By the 1880s numerous other azo dyes, such as para red and primuline red, were developed. Since that time, most modern dyestuffs have been derived from diazotized aromatic amines, and hence are sometimes known as diazo dyes. The simplest azo dyes are yellow, but changing the number of chromophores or the backbone structure can produce red, violet, blue and even black dyes. Azo dyes are used as textile colorants, and well as in industrial paints, printing inks, varnishes, plastics, crayons and other products. In recent years, many high performance azo pigments have been developed that meet the stringent lightfastness requirements required for artwork (Berrie and Lomax 1997).

See also Naphthol, Naphthol pigment, Para red, Lithol red, Arylide, Diarylide, Nickel-azo, Disazo pigment, and Benzimidazolone.

Synonyms and Related Terms

diazo dyes; azo pigments; coal tar colors; ice colors; arylide dyes; Azofarbstoff (Deut.); colorante azoico (Esp.); colorants azoïques (Fr.); colorants azo (Fr.); colorante azoico (It.); corante azo (Port.)

Risks

Some azo dyes are highly toxic and carcinogenic.

Resources and Citations

• B.Berrie, S.Q.Lomax, "Azo Pigments: Their History, Synthesis, Properties and Use in Artists' Materials" in Studies in the History of Art, No.57, National Gallery of Art, Washington DC, 1997.
• Colorants Industry History at colorantshistory.org

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 284

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• Hoechst Celanese Corporation, Dictionary of Fiber & Textile Technology (older version called Man-made Fiber and Textile Dictionary, 1965), Hoechst Celanese Corporation, Charlotte NC, 1990

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Encyclopedia Britannica, http://www.britannica.com Comment: "azo dye" [Accessed April 1, 2002

• Meredith Dorner "Early Dye History And The Introduction of Synthetic Dyes Before The 1870s" -http://www.smith.edu/hsc/silk/Papers/meredith.html

• Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980

• Wikipedia: http://en.wikipedia.org/wiki/Azo_dye (Accessed Jan. 15, 2006)