Preparation of Azo Dyes from Sulfanilamide (PDF …
Preparation of Azo Dyes from Sulfanilamide
In 1945, the Allied Control Council took charge of the assets of IG Farben, and teams of Allied scientific and technical investigators delved into the secrets of all aspects of German industry. Their findings, the US FIAT (Field Intelligence Agency Technical) and British BIOS (British Intelligence Objective Subcommittee) reports, were made widely available, and textbooks on dyemaking began to cite German advances from the 1930s (notably Krishnasamy Venkataraman's two volume Chemistry of Synthetic Dyes, based on his visit to post-war Germany). These included water soluble dyes for cellulose acetate, metallized azo dyes for nylon 6, direct cotton dyes, and benzo fast chrome dyes for wool and cellulose.
In 1959 and 1961, respectively, ICI and Hoechst filed patents for reactive dyes containing two different functional groups (heterobifunctional dyes), but the first dye of this type was not manufactured until 1975 when Hoechst made available Remazol Brilliant Red SBB, which contained three reactive groups. The first series of multifunctional dyes, the Sumifix Supra range, was introduced by Sumitomo of Japan in 1979, and thirteen of these colorants are now available. They all contain a monochlorotriazine and a vinylsulfone group. Hoechst, Nippon Kayaku, Bayer and CIBA-GEIGY brought out similar colorants in the 1980s, and the number of patent applications for this group has now reached well over one hundred. Reactive dyes are a principal product of the German-Japanese partnership of Hoechst with Mitsubishi Kasei Co. Ltd.
A synthesis of a library of potential antibiotic azo dyes is ..
March 1956 was the centenary of the discovery of Perkin's mauve, and the event was celebrated, like the fiftieth anniversary, by international gatherings in London and New York. Appropriately, the ICI Dyestuffs Division marked the event with the announcement of the first successful fiber reactive dye, reacting chemically with the fiber to form covalent bonds. These exceptionally fast dyes became the first members of the Procion range, ideal for cotton dyeing (Procion Yellow R, Procion Brilliant Red 2B, and Procion Blue 3G). In 1957, they were supplemented by CIBA's Cibacron, and imitated by Hoechst's Remazol, which used a different reactive principle. The CIBA colors were actually the result of technical agreements with ICI over use of cyanuric chloride as intermediate and CIBA's pioneering work with monochlorotriazine groups.
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. 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."
Preparation of Para Red and Related Azo dyes - …
From the 1950s the cotton industry of Hong Kong that once satisfied the needs of Thailand, Indonesia and the Far East began to make massive inroads into European and American markets. Growing production of textiles meant growing consumption of dyes and textile chemicals, and new opportunities for Asian manufacturers of these products. The dye industries of Indonesia, Pakistan, South Korea, Taiwan, Thailand, and the People's Republic of China, like that of Mexico and a number of developing countries, began with low technology products that satisfied local markets. Today Korea manufactures important intermediates; and China has considerable production capacity, including intermediates such as beta naphthol. In Pakistan, Pak Dyes, set up in collaboration with Bayer and Hoechst, produces large amounts of azo dyes (200 tons per annum) and sulfur black (300 tons each year). The industry in Pakistan is partially state owned, but in August 1992 a privatization commission invited bids for shareholdings.
During the 1940s and early 1950s research was aimed at fast dyes for cellulose, colorants for the increasingly popular nylon and other new synthetics, and chemical theory as it related to color, constitution and dye fastness. Progress was made with new azo, basic, anthraquinone, indigoid, sulfur, and phthalocyanine dyes. Pre-war developments were followed up. For example, ICI had introduced its Solacet range of water soluble dyes for cellulose acetate as early as 1933; L. B. Holliday had launched the Supracet disperse dyes for acetate and, later, nylon.
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Week 9: Synthesis of Azo Dyes « OChemOnline
Martius once again purchased a new BASF product and delivered it to Hofmann. Hofmann published the formulae of the three known azo dyes, as well as the reaction conditions, and the new process was now taken up by all the leading dye firms. In Germany, this encouraged moves towards a unified patent law, which was introduced in 1877. It had been set up with Hofmann's assistance, representing the newly formed German Society of Chemical Industry Interests (1876). The monopolies on azo and other dyes could now be protected throughout the entire German empire, and the impact of scientific method encouraged the establishment of dedicated industrial research laboratories. The new German inventions were also patented in other countries.
26/03/2008 · Week 9: Synthesis of Azo Dyes
Witt found the orange dye, with the predicted properties, and it was marketed as London yellow. Caro had come across a similar reaction, and he shared details with Witt at the "Special Loan Exhibition at the South Kensington Museum, London, in 1876. The BASF version was known as chrysoidine. This was the first successful azo dye based on starting with two different amino compounds. Francois Zacharie Roussin made other azo dyes using naphthalene intermediates, and these were manufactured by Poirrier in Paris (Poirrier had purchased rights to the Renards' patents following the collapse of La Fuchsine).
Preparation of Dis-Azo Dyes Derived from p …
It was soon realized that in the diazo reaction different combinations of atomic groupings could be introduced. The combinations seemed infinite and many thousands of experiments were undertaken. Not many commercial azo dyes resulted, but those that were successful made massive contributions to the balance sheets and fueled the demand for more research. New intermediates were introduced, including aniline in which amino group hydrogens had been substituted, and hydroxy and amino derivatives of naphthalene. When the amino compounds of toluene were introduced redder dyes were created.
Preparation of Azo Dyes Essay - 2017 Words - StudyMode
The azo work enabled Witt to put forward a theory of color and molecular constitution in 1876. This was the beginning of all modern theories of dyeing. Groupings of atoms that were essential for the specific properties of color and dyeing were defined. This made it possible to predict the type of compounds that might be both colored and capable of adhering to fibers, directing the course of industrial research in a way that had not been possible before. Later versions of the theory, like Henry E. Armstrong's quinonoid theory of 1888, led to further refinements.
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