Table 2: Zone of Inhibition (ZoI) for azo dyes at 20 mg/ml

Objective: To synthesizeazo dyesand evaluate their antimicrobial potential.


From 1881, BASF fought a patent case over an important red azo dye (fast red AV) with Ivan Levinstein. The German firm was declared victor in 1887, after the affair had reached the House of Lords. The Dawson brothers of Huddersfield also came up against the might of the BASF in patent disputes.

The heterocyclic moiety was coupled with diazotised aromatic amines to afford the respective azo or hydrazono systems.

Azo Dyes - School of Chemistry | School of Chemistry

When Simpson, Maule & Nicholson in Britain gained a brief monopoly on the most important process for magenta, its competitors had cause to look elsewhere for new opportunities. . The Holliday family of Huddersfield opened an office in New York during 1864, and began to manufacture aniline and aniline dyes, and preparations from natural dyes. This greatly assisted the introduction of aniline black printing in the United States.

Seven azo dyes namely 4-((4-nitrophenyl)diazenyl)naphthalen-1-ol, 4-((4-hydroxynaphthalen-1-yl)diazenyl)benzoic acid, 1-((4-nitrophenyl)diazenyl)naphthalen-2-ol, 4-((2-hydroxynaphthalen-1-yl)diazenyl)benzoic acid, 4-((4-amino-2-hydroxyphenyl)diazenyl)benzoic acid, 4-amino-3-((4-nitrophenyl)diazenyl)benzoic acid and 4-amino-3-((4-carboxylphenyl)diazenyl)benzoic acidwere synthesized. Of these, 4-((4-nitrophenyl)diazenyl)naphthalen-1-ol (p-NAαN) and 4-((4-hydroxynaphthalen-1-yl)diazenyl)benzoic acid (p-ABAαN), have shown antimicrobial activities. 4-((4-nitrophenyl)diazenyl)naphthalen-1-ol (p-NAαN)in particular, has been shown to inhibit most strains of microorganisms at lower concentrations. We would therefore like to publish these findings. The results have encouraged us to further investigate synthetic analogues of these azo compounds with the hope of improving upon antimicrobial activity and provide firm comparison with standard antimicrobial agents. Results obtained from these structural modifications will form the basis for subsequent publications.

To understand the formation of azo dyes

Links with eastern Europe are found in the United States, where Fabricolor has close connections with Synthesia and Spolek of Czechoslovakia. Spolek, founded in 1856, had been absorbed by IG Farben in the early 1930s. At this writing Spolek employs some 800 people and produces 4,000 metric tons annually. Synthesia, in Pardubice, employs 1,800 people, with an annual production of 12,000 metric tons. The dyestuff division of Synthesia was formed in 1939, the company having previously been involved primarily in the manufacture of explosives. Both companies market their dyes through Ostacolor, in Pardubice.

Synthesis of azo pyridone dyes (PDF Download Available)

The 1970s saw the beginning of a series of cutbacks that would reduce the size of the national industry by almost half. This was initially caused by the creation of over-capacity in anticipation of the growth of synthetic fibers, the oil crises, then by concern over pollution (especially US government health and safety regulations), and finally by worldwide recession. In particular, environmental factors began to favor the manufacture of the important anthraquinone vat dyes outside the United States.

Azo-dye Synthesis The diazo-coupling reaction

The conditions of sale had been agreed on 1 October 1982, and early in the following year ICI Francolor SA was created, a wholly owned subsidiary of ICI incorporating its former sales agency, ICI France.[67] ICI had thus inherited not only the interests of the successors to Perkin, Simpson, Maule & Nicholson, Levinstein, the Hollidays, and Morton, but also the innovative tradition established by Poirrier at Saint Denis, Paris, where in the 1860s the new alkylation of aniline process was first conducted. Not far away, at Villers Saint Paul dye making was fully computerized in 1982, while at Oissel, "red and yellow azo dyes are synthesized by a continuous process. This is believed to be the first and only one of its kind in the world."

Microscale Chemistry - The microscale synthesis of azo dyes

ICI's response was to "strengthen its position as a world supplier of dyes, pigments and auxiliaries through the proposed acquisition of the French chemicals company PCUK-Produits Chimiques Ugine Kuhlmann."[66] The acquisition of PCUK , whose dyes were sold under the Francolor trademark, took place late in 1982, and included manufacturing units at Oissel (south of Rouen specializing in azo dyes and pigments). Saint Clair du Rhone (midway between Lyon and Grenoble; azo leather and triphenylmethane dyes), and Villers Saint Paul (north of Paris; phthalocyanine blues and Solanthrene vat dyes).