Purple, Tyrian

12 The painting The Discovery of Purple Snails is by Theodore von Tulden (1606-1676). Heraclesob-served how the mouth of his dog turned red after it had chewed a purple snail. 

Also in Jewish culture, located right adjacent to the Phoenician Empire, purple was a greatly prized colourant. In the book of Exodus, Chapter 28, verses 4-8, (English Standard Version) can be found the following description  

The distinction between blue and purple and scarlet ( blue and red purple in the German Luther Bible) refers to the different shades, which range from reddish-violet to bluish-violet according to the species of snail (Fig. 

13 Purple snails besides Murex brandaris (for reddish-purple, each on the right), Trunculariopsis trunculus [31] (for bluish-purple each on the left), Murex erinaceus and Purpura haemostoma may also be used for the preparation of Tyrian purple. By the South Harbour of Saida in Lebanon (Sidon in the ancient world) the beach, 25 metres in breadth and hundreds of metres long, is covered to a depth of several metres with shells of Trunculariopsis trunculus. 

[32-34] Many species of snail produce 6-bromoindigo and indigo along with purple. 

Another dye of animal origin achieved fame for quite a different reason it was so labor-intensive to produce, so difficult to achieve even small amounts for dyeing purposes, that it s very scarcity served it very weU indeed it became the Royal purple, Tyrian purple, the color only royalty could safely wear and not risk being condemned to death. We are speaking of course, of indigo s first cousin, 6,6 -dibromoindigo, and other relatives. 

The color was, and still is, prepared from several mollusks including Murex brandaris, Murex trunculus and Purpura haemostoma, found on the shores of the Mediterranean and the Atlantic coast as far as the British Isles [31, 32]. The method of extraction and preparation of the colorant was one of the most complex, time-consuming, and labor-intensive activities carried out by the ancients. The reasons are (1) it purportedly takes 10,0(X) shellfish to produce one gram of the pure colorant (see Fig. 4.7) (2) the colorant itself is not actually present in the living animal but its precursor must be excised from the snail s hypobranchial gland (3) the colorant must be produced by a complex chemical process involving enzymatic hydrolysis of the dye precursors and subsequent photochemical oxidation. 

Although some archaeologists attribute discovery of the color to the ancient Minoans (of Crete and other Aegean Islands) around the eighteenth century BCE, 

The color purple also plays an important role in the development of biological stains. From ancient times, purple was considered to be the most beautiful, stable and precious of all colors. Today, it is critical to the staining of blood. The journey of the Tyrian purple of the ancients to the Tyrian purple of Wilham Henry Perkin and beyond is beautifully documented by Krafts, et al. A major stage on this journey was the 1891 discovery by Ernst Malachowski of a borax-alkalinized methylene blue stain that rendered the nucleus of Plasmodium falciparum, the malarial parasite, visible for the first time - in all its purple glory [63]. 

---

For more on Tyrian purple see the article Indigo and Tyrian Purple—In Nature and in the Lab in the November 2001 issue of the Journal of Chemical Educa tion pp 1442-1443... 

As early as 2500 bce m India indigo was used to dye cloth a deep blue The early Phoenicians discovered that a purple dye of great value Tyrian purple could be extracted from a Mediterranean sea snail The beauty of the color and its scarcity made purple the color of royalty The availability of dyestuffs underwent an abrupt change m 1856 when William Henry Perkin an 18 year old student accidentally discovered a simple way to prepare a deep purple dye which he called mauveme from extracts of coal tar This led to a search for other synthetic dyes and forged a permanent link between industry and chemical research... 

Textile dyes were, until the nineteenth century invention of aniline dyes, derived from biological sources plants or animals, eg, insects or, as in the case of the highly prized classical dyestuff Tyrian purple, a shellfish. Some of these natural dyes are so-caUed vat dyes, eg, indigo and Tyrian purple, in which a chemical modification after binding to the fiber results in the intended color. Some others are direct dyes, eg, walnut sheU and safflower, that can be apphed directly to the fiber. The majority, however, are mordant dyes a metal salt precipitated onto the fiber facUitates the binding of the dyestuff Aluminum, iron, and tin salts ate the most common historical mordants. The color of the dyed textile depends on the mordant used for example, cochineal is crimson when mordanted with aluminum, purple with iron, and scarlet with tin (see Dyes AND DYE INTERMEDIATES). 

Another ancient dye is the deep blue indigo [482-89-3], the presence of two bromine atoms at positions gives the dye Tyrian purple [19201 -53-7] once laboriously extracted from certain sea shells and worn by Roman emperors. 

Indigoid dyes represent one of the oldest known classes of dyes. For example, 6,6 -dibromoindigo [19201 -53-7] (44) is Tyrian Purple, the dye made famous by the Romans. Tyrian Purple was so expensive that only the very wealthy were able to afford garments dyed with it. Indeed, the phrase "bom to the purple" is still used today to denote wealth. 

Kermisic Acid. Many accounts claim that kermisic acid [476-35-7] (Cl Natural Red 3 Cl 75460) is the oldest dyestuff ever recorded (23). The name kermes is derived from an Armenian word meaning Httle worm for which the later Latin equivalent was vermiculus, the basis of the Knglish word Vermillion. The dye was obtained from an oriental shield louse, K. ilicis which infest the holm o5kQuercus ilex and the shmb oak. coccifera. The dye produces a brilliant scarlet color with an alum mordant. Although expensive, it was cheaper than its rival Tyrian Purple. It was in great demand until the sixteenth century when it was displaced by carminic acid. 

Tyrian Purple was the most expensive and rare dye of the ancient world principally because only a small amount of dye could be obtained from each moUusk, roughly 0.12 mg (95). It was always considered a color of distinction and restricted to regal and ecclesiastical uses ia the Eastern Roman Empire, the heir to the throne at By2antium bore the proud name Porphjro-Genitur, bom to the purple. The Hebrews used purple ia many decorations of the Tabernacle (23). 

AD Strabo described dyeworks for obtaining tyrian purple (dibromoindigo) in his Geographica 100 Use of salt to purify noble metals... 

P. Friedlander showed that Tyrian Purple from Murex brandaris was 6,6 -dibromoindigo (previously... 

The magnificent purple pigment referred to in the Bible and known to the Romans as Tyrian purple after the Phoenician port of Tyre (Lebanon), was shown by P. Friedlander in 1909 to be 6,6 -dibromoindigo. This precious dye was extracted in the early days from the small purple snail Murex brandaris, as many as 12000 snails being required to prepare 1.5 g of dye. The element itself was isolated by A.-J. Balard in 1826 from the mother liquors remaining after the crystallization of sodium chloride and sulfate from the waters of the Montpellier salt marshes ... 

This noble but naive attempt - bearing in mind that only the molecular formula of C20H24N2O2 was known at the time - was doomed to fail. In subsequent experiments with aniline, which was fortunately contaminated with toluidines, Perkin obtained a purple product in low yield. Perkin was quick to recognize the commercial potential of his findings the natural dye, Tyrian purple, which was extracted from a species of Mediterranean snail, cost more per kilogram than gold in 1856. Within a few years the first commercial plant for the production of mauveine was in operation. 

Vat Dyes. Vat dyes are insoluble in water. Indigo, for example, an ancient blue dye, is probably the best-known example of an ancient vat dye others include woad and Tyrian purple. Since the process of dyeing requires that the dye be in solution, dyeing with a vat dye (or vat dyeing, as the process is known) is possible only after the vat dye has been made soluble by a relatively long and somewhat complicated chemical procedure. The terms vat dye and vat dyeing are probably derived from the large tanks or "vats", in which the process was carried out in ancient times. 

Tyrian purple was derived from the "purple snail," the common name for what, in reality, are several species of mollusks of the genus Murex. Each one of the mollusk species yielded a slightly different variety of purple. In Tyre, where the most prized purple dye was produced, Murex brandaris snails were those most abundant and generally used, while in Sidon, not far to the north of Tyre, an amethyst purple variety of the dye was obtained from... 

Friedlander, P. (1909), Tyrian Purple, Berichte der Deutscher Chemischer Geseltshaft 42, 765-770. 

C.J. Cooksey, R.S. Sinclair, Colour variations in Tyrian purple dyeing, Dyes in History and Archaeology, 20, 127 135 (2005). 

Vat dyes (the best known are Tyrian purple, indigo and woad) are insoluble in water. Before dyeing, they must be reduced into water-soluble leucoforms. After impregnation of the textile, dyestuffs are again oxidized into colour forms. As far as their extraction is concerned, aprotic solvents are usually recommended, e.g. pyridine, dimethylformamide or dimethylsulfoxide. 

Indigoid species are also present in another dyestuff, Tyrian Purple, extracted from molluscs from the Muricidae family. It owes its specific red shade to the presence of bromoindigoids. In the extract of the dyestuff, after chromatographic separation of its components,[44] in addition to indigotin, indirubin and isoindigo, 6,6 -dibromoindigotin is... 

Type metal, 3 53, 24 798 Type N hydrated lime, 15 29 Type S hydrated lime, 15 29 Type V gel-silica, 23 75-76 Type VI gel-silica, 23 76 Tyrian purple color, 7 332 Tyril, 7 639 D-Tyrosine... 

The appreciation of color and the use of colorants dates back to antiquity. The art of making colored candy is shown in paintings in Egyptian tombs as far back as 1500 bc. Pliny the Elder described the use of artificial colorants in wine in 1500 bc. Spices and condiments were colored at least 500 years ago. The use of colorants in cosmetics is better documented than colorants in foods. Archaeologists have pointed out that Egyptian women used green copper ores as eye shadow as early as 5000 bc. Henna was used to redden hair and feet, carmine to redden lips, faces were colored yellow with saffron and kohl, an arsenic compound, was used to darken eyebrows. More recently, in Britain, in the twelfth century, sugar was colored red with kermes and madder and purple with Tyrian purple. 

The Chemistry of Indigo Dyeing.—On account of its insolubility the dye itself cannot be applied directly to the fibre. Yet an indirect process of great antiquity is available, for Tyrian purple has been identified as 6 6 -dibromoindigo 1 by Friedlander. The indigo is made soluble... 

They found eager customers in Egyptians and Etruscans, and later among the Greeks and Romans. Jewish traditions accorded Tyrian purple an important place, and there are several Biblical references to it. The demand for the dye exceeded the supply for centuries, guaranteeing that the price was always high. At times... 

---