Monosulphonic acids

Naphthalene disulphonic acids are prepared by more prolonged sulphonation than in the preparation of the monosulphonic acids. Four isomeric acids are obtained. 

Betzemeier et al. (1998) have used f-BuOOH, in the presence of a Pd(II) catalyst bearing perfluorinated ligands using a biphasic system of benzene and bromo perfluoro octane to convert a variety of olefins, such as styrene, p-substituted styrenes, vinyl naphthalene, 1-decene etc. to the corresponding ketone via a Wacker type process. Xia and Fell (1997) have used the Li salt of triphenylphosphine monosulphonic acid, which can be solubilized with methanol. A hydroformylation reaction is conducted and catalyst recovery is facilitated by removal of methanol when filtration or extraction with water can be practised. The aqueous solution can be evaporated and the solid salt can be dissolved in methanol and recycled. 

The bonding forces involved in hydrophobic interaction can be quite specific to the structure of the dye ions involved. A series of isomeric derivatives of 2-phenylazophenol-4-sulphonic acid, each containing a trifluoromethyl substituent, was synthesised recently. The aqueous solubility of these monosulphonated acid dyes was found to be dependent on the location of this specific grouping in the dye molecule [4]. 

Table 3.8 Substantivity of symmetrical disazo dyes derived from naphthylamine monosulphonic acids [70]...

Difficulties of incompatibility can arise with mixtures of basic dyes on acrylic fibres because of competition for the limited number of dyeing sites available and the differences between dyes in terms of affinity and rate of diffusion. The rate of uptake of each dye when applied in admixture with another is invariably slower than when the dye is applied alone at the same concentration. Competition effects of this kind can lead to serious practical problems unless the dyes are carefully designed and selected to have similar dyeing characteristics [97,98,104,105]. Dyes with exceptionally low affinity and rapid rates of diffusion have been developed, offering improved migration on acrylic fibres [106]. These dyes have migration properties not unlike those of monosulphonated acid dyes on nylon. 

Acid dyes are normally applied to wool at acidic pH values but are washed under neutral or mildly alkaline conditions. Forces of affinity between dye and substrate tend to retard desorption. The higher the degree of sulphonation in a series of naphthylazo-2-naphthol dyes (Table 3.39), the higher is the rate of desorption into sodium borate solution at 40 °C. With a series of monosulphonated acid dyes the desorption rate under these conditions was inversely related to the affinity of the dye for wool at pH 3 and 60 °C (Table 3.40). 

Table 3.40 Affinity and desorption rate of monosulphonated acid dyes on wool [181]...

BENZENE MONOSULPHONIC ACID FROM BENZENE AND SULPHURIC ACID... 

From naphthalene two monosulphonic acids are obtained, namely, naphthalene-a- and -/8-sulphonic adds ... 

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 introduction of nitro groups proceeds the more rapidly the more sulpho groups "sulphophenol" contains. The nitration of disulphonic acid is faster than the nitration of monosulphonic acid, but not so fast as the nitration of trisulphonic acid. 

By the action of nitric acid on a-naphthol mono- and di-sulphonic acids (obtained by direct sulphonation), the sulpho-groups are replaced by nitro-groups, while on nitration of a-naphthol trisulphonic acid, one sulpho-group remains intact [8], the other two being replaced by nitro-groups. The compound formed is a monosulphonic acid of dinitronaphthol. This acid forms long yellow needles, which are easily soluble in water [9]. 

Dimethylamidoazobenzene is obtained by action of dimethyl-aniline on hydrochloride of diazobenzene, and if the latter be replaced by diazobenzenesulphonic acid, the above monosulphonic acid is formed. 

The monosulphonic acid forms brilliant violet needles, which are sparingly soluble. Its salts are yellow, and mostly well crystallised. 

At present three monosulphonic acids have been obtained from a-naphthol, but the constitution of only one of these is knowTi with any degree of certainty. This is the aa-acid prepared by Nevile and "V inther, and studied more closely by Witt. It is obtained by decomposition of the diazo-compound of naphthionic acid with water, and from its method of formation is constituted according to the formula ... 

The azo-dycs from G-acid are yellowish and easily soluble, and are very similar to those from the a-monosulphonic acid. 

From /8-naphthol-a-monosulphonic acid [48] and o-diazo-naphthalenesulphonic acid. Is a beautiful scarlet dyestuff which dissolves in sulphuric acid with a reddish-violet colour. 

Commercial Biebrich scarlet is generally this disulphonic acid, sometimes it contains the monosulphonic acid also. Both give a green solution with concentrated sulphuric acid. The shade obtained on wool and silk is a beautiful cochineal scarlet. 

The isomeric monosulphonic acids of yS-naphthol react with di-... 

By the action of concentrated sulphuric acid on y3-naphthyl-amine two monosulphonic acids are first formed, 9-naphthylaminc-a-sulphonic acid (corresponding to the crocein acid from -naph-thol), and the yS-naphthylamine-7-sulphonic acid. 

Por a long time it was thought that the anthraquinonedisul-phonic acids gave rise to the formation of alizarin, but this assumption was based on an error. The monosulphonic acid alone is capable of giving alizarin, while the disulphonic acids yield isopurpurin and flavopurpurin. This was already known to some technologists in 1871, but was first published by Perkin in 1876... 

For production of monosulphonic acid a somewhat concentrated fuming sulphuric acid (containing 30 to 40 per cent, anhydride) is required, and the sulphonation should take place at as low a temperature as possible. 

The monosulphonic acid is separated from the disulphonic acids simultaneously formed by fractional crystallisation of the sodium salts. By saturating the acid mixture with soda, the salt of the monosulphonic acid separates first. At present the sulphonation is carried out so as to produce as much monosulphonic acid as possible with only a little disulphonic acid. 

Alizarine blue may be oxidised by action of fuming sulphuric acid, the process being analogous to that used for the preparation of Alizarin, Bordeaux. At 50° to 60° a dyestuff called Alizarin Blue-green is formed, and is best isolated in form of its bisulphite compound. It is a monosulphonic acid of mono-oxyalizarin blue. 

If the mixture be heated to 120°, or if alizarin blue-green is heated with concentrated sulphuric acid to 120°, an intramolecular change takes place, a new mono-oxyalizarin blue monosulphonic acid being formed. This body is an article of commerce, and is Icnown as Alizarin Green S. 

The difficulties encountered in the sulphonation of rosaniline are altogether absent in that of the phenylated rosanilines. A monosulphonic acid is formed by the action of concentrated sulphuric acid at a comparatively low temperature, while by a more energetic sulphonation two, three, and even four sulpho-groups may be introduced into the molecule. 

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