Mauve dye

The first synthetic dye is developed by William H. Perkin (English) he accidentally creates a mauve dye from the impure aniline in coal tar. 

Worked Example 10.1 The following data refer to the adsorption of the red-mauve dye from beetroot juice on porcelain at 25 °C. (1) Show that the data obey the Langmuir adsorption isotherm. (2) Demonstrate that 1.2 x 10 8 mol of dye adsorb to form a mono-layer. (3) Estimate the area of a single dye molecule if the radius of a plate was 17.8 cm (we assume the formation of a complete monolayer). 

PERKIN, SIR WILLIAM HENRY (1838-1907). An English chemist who was the first to make a synthetic dyestuff (1856). He studied under Hofman at the Royal College of London. Perkin s first dye was called mauveine, but he proceeded to synthesize alizarin and coumarin, the first synthetic perfume. In 1907 he was awarded the first Perkin Medal, which has ever since been awarded by the American Division of the Society of Chemical Industry for distinguished work in chemistry. Not withstanding the fact that Perkin patented and manufactured mauve dye in England, the center of the synthetic dye industry shifted to Germany, where it remained until 1914. 

Perkin sent a sample of his mauve dye to Pullar s of Perth, who tried it out in their works and gave it a favourable report, provided that it could... 

Recognizing the importance of his discovery, Perkin went into business producing the mauve dye with his father and brother. Mauve became the first commercially successful coal-tar dye, and it brought riches and fame to its discoverer. In a sense, quinine did reward Perkin, but not exactly the way Hofmann had predicted. 

After identifying and classifying many biological compounds, chemists began to pursue the next obvious step, which was to attempt to synthesize the more important natural products. Syntheses that were pursued most vigorously were those of compounds with medicinal activity, and it may be recalled that Perkin was looking for quinine when he found mauve dye. Though the synthesis of quinine eluded chemists for another half-century, another folk remedy known to be a powerful fever reducer succumbed to the chemist s efforts more readily aspirin. 

The methylene blue and resazurin reduction methods indirectly measure bacterial densities in milk and cream in terms of the time interval required, after starting incubation, for a dye—milk mixture to change color (methylene blue, from blue to white resazurin, from blue through purple and mauve to... 

Oxidation. Aromatic amines can undergo a variety of oxidation reactions, depending on the oxidizing agent and the reaction conditions. For example, oxidation of aniline can lead to formation of phenyUiydroxylamine, nitrosobenzene, nitrobenzene, azobenzene, azoxybenzene or -benzoquinone. Oxidation was of great importance in the early stages of the development of aniline and the manufacture of synthetic dyes, such as aniline black and Perkin s mauve. 

Perkin turned his full attention to the purple substance, and within six months he was producing the new dye commercially. The dye was named mauveine, and the color is known as mauve. Today we know the structure of mauveine, which appears in the inset. We also know that Perkin was very lucky, because mauveine was produced from an impurity in the chemicals that he used. 

William Henry Perkin, an 18-year-old working in the back room and outdoor shed of his London home, had discovered in black coal tar a beautiful purple dye that would change the world. For the first time in history, color could be democratized. William Henry Perkin and his purple, later known as mauve, rescued the poor and middle classes from their age-old austerity of hues. Natural dyes were expensive and, before Perkin s synthetic mauve, millions of poor people lived their lives in untreated drab and dingy fibers. Even for the middle class, pieces of brilliantly dyed cloth were treasures to be reused from garment to garment and from year to year. It was the schoolboy William Henry Perkin and his successors who would give the world the ample abundance of tints that only the rich had previously enjoyed. 

While Nicolas Leblanc and his washing soda helped start the bulk chemical industry, Perkin s mauve spawned the world s dye and pharmaceutical drug industries. His synthetic dye was the first in a cascade of colors that institutionalized scientific research, professionalized chemists, changed the economies of vast regions, and helped make turn-of-the-century Germany the world s leading industrial power. Perkin was an ado-... 

That spring, Perkin mailed a precious sample of his purple to a Scottish dye firm. After exposing the sample to sunlight, the company s owner, Robert Pullar, wrote back that Perkin s mauve had kept its color better than any other lilac on the market. If your discovery does not make the goods too expensive, it is decidedly one of the most valuable that has come out for a very long time. This colour is one which has been very much wanted in all classes of goods, and could not be obtained fast on silks, and only at great expense on cotton yarns. ... 

Then, as suddenly as it had appeared, mauve mania was over and the elegant world whirled on to a new color. A magnificent red never seen before in dyes, the French hue was variously named fuchsia for the flower blossom and magenta for a northern Italian town where the Emperor Napoleon III had defeated Austria that summer. Like Perkin s mauve, magenta was a wildly popular synthetic dye with humble origins in coal tar, that is, in aniline and other similar compounds. 

Hofmann himself made a fabulously brilliant violet that replaced Perkin s mauve, even though the professor s dye was not as fast as his student s. Dyers thought no one would want fleeting tints, but, no matter, the experts were wrong. Women craved raucous and dramatic hues they... 

As the chemical industry expanded, Perkin continued his own scientific research in the peace of his private laboratory. He had not lost his touch. Among the synthetic methods he discovered is one now called the Perkin reaction. He used it to make a synthetic substitute for a vegetable substance called coumarin, which has a pleasant, vanillalike odor. Coumarin spawned the synthetic perfume business and made luxurious scents available to all. Once again, a Perkin chemical started a new industry, albeit a modest one in comparison with dyes and pharmaceuticals. Despite the worldwide impact of Perkins discoveries, he was not knighted by the British monarchy until 1906, the fiftieth anniversary of his discovery of mauve. The world chemistry community feted him lavishly that year, and he traveled to the United States collecting further honors. A year later, at the age of 69, he died peacefully, at home. 

The dye responsible for the red-mauve colour of beetroot juice is potent, because a small amount imparts an intense stain on most crockery. It has a large extinction coefficient s (see Chapter 9). The dye is fairly difficult to remove, so we safely assume the adsorption bonds are strong and chemisorptive by nature. 

Perkin, W. H. J. Chem. Soc. 1868, 21, 53. William Henry Perkin (1838—1907), bom in London, England, studied under Hofmann at the Royal College of Chemistry. In an attempt to synthesize quinine in his home laboratory in 1856, Perkin synthesized mauve, the purple dye. He then started a factory to manufacture mauve and later other dyes including alizarin. Perkin was the first person to show that organic chemistry was not just mere intellectual curiosity but could be profitable, which catapulted the discipline into a higher level. In addition, Perkin was also an exceptionally talented pianist. 

The conservative Scottish textile manufacturers were slow to adapt to this new dye, and the leadership of innovation went to French textile manufacturers by default. When Empress Eugenie of France wore mauve in public, it impressed Queen Victoria to wear mauve at her daughter s wedding, so there was a wave of enthusiasm for synthetic dye. Perkin became very successful in commerce, and gave up business for chemistry research later in life. Fie was knighted in 1906, at the 50-year anniversary of his discovery, and died in 1907. Mauve had a short commercial life, as its early success led to further experimentations that produced many better dyes, particularly in Germany. This marked the beginning of the synthetic dye industry, which was the first modern chemical industry. 

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