Alizarin Synthesis

In summary, high pressure ammonia synthesis was nothing less than another major step towards the industrialization of academic chemistry on the lines pioneered by BASF during 1869-70 with the scale up of the alizarin synthesis, and during the 1890s with the production of synthetic indigo. This created a tradition for highly risky financial... 

From the time of the first alizarin synthesis, anthraquinone has been the most versatile anthracene derivative. This applies both for dye production and for the more recent applications of anthraquinone, as an additive (redox-catalyst) in wood pulping, and as a hydrogen carrier in H2O2 production. 

Production of dyestuff intermediates based on anthraquinone commonly involves the exchange of ring substituents. The exchange of sulfonic acid groups is of particular importance, as used in the last century in the classic alizarin synthesis. 

The way a synthesis is planned has changed substantially over time. Until the beginning of the 20th century many noteworthy syntheses had been developed, c.g., of alizarin (C. Gracbc, C, Licbermann, 1869) and indigo (A, Bacycr, 1878). 

Alizarin.—The fiist synthesis of alizarin is due to C.raebe and Liebennann (i868). The present method was discoi eiecl simultaneously by these chemists and by Peikm. By the aqtion... 

The synthesis of indigo was much more difficult than that of alizarin (6.2) [43]. In 1865 von Baeyer first attempted to obtain indigo by reductive dimerisation of isatin (6.116) he finally achieved a seven-step synthesis from phenylglycine via isatin in 1878. Many syntheses have been developed subsequently for indigo, but very few of these have achieved industrial importance. 

A similar behaviour is observed in the case of the phenolsulphonic acids and in particular in that of anthraquinone, which, in its substitution reactions, is extraordinarily like naphthalene. Anthraquinone is sulphonated with more difficulty than is naphthalene, and in consequence the conditions of increased temperature which must be applied bring about the formation of the /8-acid, the important starting point for the synthesis of alizarin. In industrial practice, however, ways and means have been found for producing also anthraquinone-a-sulphonic acid, which was formerly not readily obtainable. a-Substitution takes place when the sulphonation is catalysed by mercury1 (R. E. Schmidt). 

Alizarin or l 2-dihydroxyanthraquinone is one of the most important dyes. Like indigo, the dye occurs in the plant (the madder root) as the glucoside of the leuco-compound. The cultivation of the madder plant, which, chiefly in southern France, extended over large areas, was brought to an end by the synthesis of the dye from the anthracene of coal-tar (Graebe and Liebennann, 1869). By distillation with zinc dust according to the method of Baeyer, these two chemists had previously obtained anthracene from alizarin. 

Anthracene was oxidized to anthraquinone. dibrominated, and the dibromo derivative subjected to a caustic fusion. Alizarin was obtained in an impure form and in low yield. This represented the first synthesis of a natural dye. 

Occasionally in the synthesis of phenols by this route oxidation products are formed. A particular example is provided by the alkali fusion of sodium anthraquinone-2-sulphonate during which a second hydroxyl group is introduced into the 1-position, forming the dyestuff alizarin (1) (cognate preparation in Expt 6.99). In the procedure described the oxidation step is promoted by the deliberate introduction of potassium chlorate as an oxidant. 

Synthesis of the first metallizable azo dye, Alizarin Yellow (R. Nietzky)... 

Artificial dyes in the laboratory of the Lancashire calico-printer John Lightfoot included his own invention of aniline black he also pioneered new methods for mordanting and the use of vanadium in aniline black printing.104A general account has been given of the role of rosaniline in the development of the synthetic dye industry.105 A paper on quinones focuses chiefly on the case of anthraquinone and the synthesis of alizarin from anthracene.106... 

With the influence of an artist friend interested in painting and dyes, he started to develop aniline purple (Tyrian purple) production, which he patented in 1856 and set up a factory for. The dyestuff industry soon flourished. In 1859, Emanuel Verguin prepared the important dye fuschine, which was subsequently produced in Basel. In 1869, Perkin patented the synthesis of the natural dye alizarin, at the same time as Caro, Lieberman, and Graebe did so in Germany. Later, moreover, Perkin prepared alizarin from anthracene, which had been... 

Technical Observations Alizarin was the first naturally occurring coloring matter which was successfully prepared synthetically on a commercial scale. This synthesis was a triumph for the then young coal-tar dye industry, and for a long time alizarin was its most important product. The world production of alizarin (as 100 per cent material) was about 2,800,000 kilograms yearly, of which the Badische A.S.F. supplied 2,000,000 kilograms. In more recent times, the consumption of alizarin has been greatly reduced as a result of the competition of more easily applied red dyes of the azo series, especially some of the equally fast naphthol AS combinations. 

Shortly thereafter, an inexpensive procedure for the industrial production of 1 from readily available starting materials was elaborated (Bayer, 1878)." In related efforts, chemists identified another compound, alizarine 3, which was isolated from a certain species of plants Rubia tinctoria). It was used for centuries as a natural dye. Originally very expensive, it soon became an inexpensive product owing to the ease of its synthesis from the aromatic hydrocarbon anthracene, present in coal tar (Grebe and Lieberman, 1868). ... 

Synthesis, Graebe and Liebermann.— The determination the of constitution of alizarin and its synthetic preparation are both due largely to the work of Graebe and Liebermann in 1868. 

The remarkable thing is, that while there are ten possible di-brom or di-hydroxy anthraquinones, the particular one necessary was obtained by Graebe and Liebermann. The positions of the two hydroxyl groups were determined by Baeyer and Caro. When alizarin is heated pyro-catechinol, i-2-di-hydroxy benzene, is obtained. Also when pyro-catechinol is heated with ortho- hXhaXic acid and sulphuric acid alizarin results. This last synthesis is analogous to that of anthraquinone from benzene and o //io-phthalic acid (p. 796). 

In this synthesis it is interesting that it is the mono-sulphonic acid of anthraquinone and not the di-sulphonic acid which is the intermediate product. Other syntheses have been used commercially. Anthraquinone may be converted into alizarin without sulphonation by treating it with a mixture of sodium hydroxide, potassium hydroxide and sodium chlorate and heating to 200°. Also electrolytically by passing a current through a mixture of anthraquinone and fused potassium hydroxide. 

Industrial Importance.—The synthesis of alizarin by Graebe and Liebermann was the first case of a common natural dye being prepared in the laboratory. As the synthesis starts with anthracene, a substance obtained in good yields from coal tar, it affords at once a cheap commercial source for the synthetic preparation of a natural product. Hardly any synthesis that has been worked out in the laboratory has had such an immediate effect upon industry as this one, and in addition to this it exerted a strong influence upon similar syntheses of other dyes. In 1868 Turkey red was a very common and valuable dye and the growth of the madder plant, in France especially, was an important industry. In their original paper Graebe and Liebermann make this statement ... 

The synthesis of alizarin was carried out by Graebe and Lieber-mann [23] in the same year, this being of very great importance, as the first synthesis capable of industrial application for production of a dyestuff occurring in nature. 

The synthesis of alizarin was first effected by Graebe and Liebermann in 1869. These chemists had already observed the formation of anthracene from natural alizarin by heating with zinc powder, and recognizing alizarin as a derivative of anthracene, attempted to convert anthracene into alizarin. This aim was accomplished by fusion of bibromanthraquinone with potash. In the same year Graebe, Liebermann, and Caro [14] discovered the formation of alizarin by melting anthraquinonesulphonic... 

This dyestuff is prepared by heating -nitroalizarin with glycerine and sulphuric acid. It is peculiar in so far that it possesses the lake-forming properties characteristic of the alizarin dyes, and is at the same time a weak base. Alizarin blue was discovered by Prud homme [28], and the determination of its constitution by Graebe [29] led to the synthesis of quinoline by Skraup from glycerine, nitrobenzene, and aniline. 

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