Anthraquinone sulphonic acid

Fig. 3.130. HPLC chromatograms of the test mixture detected by DAD (270 nm, upper lane) by APCI-MS-TIC (middle) and by ESI-MS-TIC (lower lane). Peak identification l=benzene sulphonic acid sodium salt 2=2-naphtalene sulphonic acid sodium salt 3=2-anthraquinone sulphonic acid sodium salt 4 = sulphorhodamine D sodium salt 5=crocein orange G 6=eriochrome black T 7=2,6-anthraquinone disulphonic acid disodium salt 8 = 1,5-naphtalene disulphonic acid disodium salt 9 = azophloxine 10 = 1,2-benzene disulphonic acid dipotassium salt. Reprinted with permission from G. Socher et al. [178].

Alizarin, the dyestuff contained in madder, is made from anthracene, another coal tar product, by the action of "sodium bichromate and sulphuric acid to form antbraquinone this is traniSformed by the action of sulphuric acid into anthraquinone sulphonic acid, the sodium salt of which when fused with soda and a little potassium chlorate yields a compound of alizarin containing sodium, from which alizarin itself is made by the action of acid. 

Alizarin is reduced to anthracene when heated with zinc-dust—a transformation which was the first step taken in determining the structure of the dye contained in madder-root. The view that alizarin is a dihydroxyl derivative of anthraquinone, follows from the fact that it is formed as the result of the fusion of anthraquinone-sulphonic acid with caustic alkalies, and from the synthesis of the dye by heating phthalic anhydride and pyro-catechol with sulphuric acid at 150° —... 

Anthraquinone sulphonic acid C6H4(CO)2CeH3S03H, an intermediate in the synthesis of dyestuffs in solution, has no action on aluminium, even at elevated temperatures. 

Dissolves in alkaline solutions to give purple-red solutions which are precipitated as lakes by heavy metal salts. Occurs naturally as a glucoside in madder but produced synthetically by fusing anthraquinone-2-sulphonic acid with NaOH and some KCIO3. Applied to the mordanted fibre. Al(OH)3 gives a bright red lake, Cr(OH)3 a red lake, FefOH) ... 

C. A typical aromatic amine. Best prepared by the prolonged action of concentrated ammonia solution at a high temperature upon anthraquinone-l-sulphonic acid in the presence of BaClj and by reduction of the corresponding nitro compound or by amination of the chloroanthraquinone. 

Anthraquinone can be brominated, chlorinated directly to the tetrachloro (I, 4, 5, 8-) stage, nitrated easily in the 1-position, but gives the 1,5-and 1,8-dinitro-derivalives on prolonged nitration the nitro groups in these compounds are easily displaced by neutral solutions of alkali sulphites yielding the corresponding sulphonic acids. Sulphonation with 20-30 % oleum gives the 2- 2,6- and 2,7-derivatives in the presence of Hg the 1- 1,5- and 1,8- derivatives are formed. 

Anthraquinone-J -sulphonic acid. Colourless leaflets, m.p. 214 C. It is used in the preparation of l-aminoanthraquinone. 

Anthraquinone is of great technical importance, as many of its derivatives form valuable dyes notable among these are the hydroxy-derivatives (alizarin, etc.)y the amino-derivatives (indanthrene, etc.) and the sulphonic acids. 

One potentially important example of CIDNP in products resulting from a radical pair formed by electron transfer involves a quinone, anthraquinone j5-sulphonic acid (23). When irradiated in the presence of the cis-syn dimer of 1,3-dimethylthymine (24), enhanced absorption due to vinylic protons and emission from the allylic methyls of the monomer (25) produced can be observed (Roth and Lamola, 1972). The phase of the polarizations fits Kaptein s rules for intermediate X... 

Upon heating anthraquinone with fuming sulphuric acid at 160° for about 1 hour, the main product Is anthraquinone-p-sulphonic acid, which is isolated as the sparingly soluble sodium salt. The latter when heated imder pressure with sodium hydroxide solution and an oxidising agent (sodium or potassium chlorate) yields first the corresponding hydroxy compound further hydroxy-lation occurs in the a-position through oxidation by the chlorate and 1 2-di-hydroxyanthraquinone (alizarin) is formed. 

Sodium anthraquinone- -sulphonate ( silver salt ). Place 60 g. of fuming sulphuric acid (40-50 per cent. SOj) in a 250 or 500 ml. round-bottomed flask and add 50 g. of dry, finely-powdered anthraquinone (Section IV, 145). Fit an air condenser to the flask and heat the mixture slowly in an oil bath, with occasional shaking, so that at the end of 1 hour the temperature has reached 160°. Allow to cool and pour the warm mixture carefully into a 2 htre beaker containing 500 g. of crushed ice. Boil for about 15 minutes and filter off the unchanged anthraquinone at the pump. Neutrahse the hot filtrate with sodium hydroxide and allow to cool, when the greater part of the sodium anthraquinone- -sulphonate separates as silvery glistening plates ( silver salt ). Filter these with suction and dry upon filter paper or upon a porous plate. A second crop of crystals may be isolated by concentration of the fitrate to half the original volume. The yield is 40-45 g. 

Electrophilic substitution at the anthraquinone ring system is difficult due to deactivation (electron withdrawal) by the carbonyl groups. Although the 1-position in anthraquinone is rather more susceptible to electrophilic attack than is the 2-position, as indicated by jt-electron localisation energies [4], direct sulphonation with oleum produces the 2-sulphonic acid (6.3). The severity of the reaction conditions ensures that the thermodynamically favoured 2-isomer, which is not subject to steric hindrance from an adjacent carbonyl group, is formed. However, the more synthetically useful 1-isomer (6.7) can be obtained by sulphonation of anthraquinone in the presence of a mercury(II) salt (Scheme 6.4). It appears that mercuration first takes place at the 1-position followed by displacement. Some disulphonation occurs, leading to the formation of the 2,6- and 2,7- or the 1,5- and 1,8-disulphonic acids, respectively. Separation of the various compounds can be achieved without too much difficulty. Sulphonation of anthraquinone derivatives is also of some importance. 

Anthraquinone-1-sulphonic acid is the traditional precursor of 1-aminoanthraquinone (6.8), the most important anthraquinone intermediate. Since it is expensive to eliminate mercury(II) ions from waste water, an alternative route via 1-nitroanthraquinone has been investigated. Nitration of anthraquinone gives, as well as the desired 1-nitro derivative, significant amounts of the 2-isomer together with 1,5- and 1,8-dinitroanthraquinones. Nevertheless, chemists at Sumitomo in Japan have optimised the nitration procedure with respect to both yield and purity of the 1-nitro compound. In particular, nitration is stopped when 80% of the anthraquinone has been substituted [5]. Nitration of anthraquinone derivatives is also of some significance. 

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). 

It seems that anthraquinone-/3-sulphonic acid is not produoed by rearrangement of the a-aoid. 

A mixture of 2 g. of potassium chlorate, 30 g. of commercial sodium hydroxide, 10 g. of finely powdered sodium /3-anthraquinone-sulphonate ( silver salt ), and 40 c.c. of water is heated for twenty hours at 170° (oil bath) in an autoclave or in an iron tube with screwed-on cap. The cooled melt is repeatedly extracted with hot water and the extracts, after being combined and filtered, are acidified while hot with excess of hydrochloric acid, which precipitates the alizarin. When the mixture has cooled the precipitate is collected at the pump, washed successively with dilute hydrochloric acid and water, and dried. 

Water, drinking Add sample to 1,2-dihydroxy-anthraquinone-3-sulphonic acid in phosphate buffer. Polarographic analyser 2 xg/L No data Quentel et al. 1994... 

Anthraquinone-2-sulphonic acid (sodium salt, H2O) [131-08-8] M 328.3. Crystd from water using active charcoal. 

Anthraquinone 2-sulphonic acid Area increase 8% not adsorbed... 

Reaction LXX. Oxidation of certain Hydrocarbons. (B., 14, 1944 A. Spl., 1869, 300 E.P., 1948 (1869).)—This reaction is confined in the aliphatic series almost exclusively to the replacement by hydroxyl of the hydrogen attached to tertiary carbon atoms. A powerful oxidising agent, e.g., chromic acid in glacial acetic acid, is necessary. In the aromatic series the reaction is somewhat more easy to accomplish when the sodium salt of anthraquinone-jS-monosulphonic acid, for example, is fused under pressure with caustic soda and a little potassium chlorate, replacement of both a hydrogen atom and the sulphonic acid group by hydroxyl occurs, and alizarin ( /f-dihydroxyanthraquinone) is obtained. 

The sulphonation of toluene (Expt 6.37) with concentrated sulphuric acid at 100-120°C results in the formation of toluene-p-sulphonic acid as the chief product, accompanied by small amounts of the ortho and meta isomers these are easily removed by crystallisation of the sodium salt of the para isomer in the presence of sodium chloride. Sulphonation of naphthalene at about 160°C yields largely the 2-sulphonic acid (the product of thermodynamic control) (Expt 6.38) at lower temperatures (0-60 °C) the 1-sulphonic acid (the product of kinetic control) is produced almost exclusively. In both cases the product is isolated as its sodium salt. In anthraquinone the carbonyl groups deactivate the aromatic nucleus towards electrophilic attack and vigorous conditions of sulphonation are required, i.e. oleum at about 160 °C. The product is largely sodium anthraquinone-2-sulphonate (Expt 6.39). 

According to Weizmann,1 anthraquinone, dissolved in concentrated sulphuric acid, is converted by electrolytic oxidation into monoxy-, dioxy-, and trioxyanthraquinone. An addition of oxalic acid to the sulphuric acid is suitable for obtaining dioxyanthraquinone. A nitrooxyanthraquinone, which is convertible by electrical reduction into amidoalizarin, is similarly obtained from mononitroanthraqninone.2 The amidoalizarin can be directly obtained from nitroanthraquinone if its solution is electrolyzed with an alternating current. The sulphonic-acid derivatives of anthraquinone behave like anthraquinone. 

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