Sulphonation aromatic

Concentrated sulphuric acid. The paraffin hydrocarbons, cych-paraffins, the less readily sulphonated aromatic hydrocarbons (benzene, toluene, xylenes, etc.) and their halogen derivatives, and the diaryl ethers are generally insoluble in cold concentrated sulphuric acid. Unsaturated hydrocarbons, certain polyalkylated aromatic hydrocarbons (such as mesitylene) and most oxygen-containing compounds are soluble in the cold acid. 

The sulphonated aromatic condensation products form a large and varied group, since formaldehyde will condense with many aromatic compounds [330], including sulphonated arylamines, phenols and aliphatic ketones the range of commercially important products is relatively limited, however. One of the oldest is the condensation product of naphthalene-2-sulphonic acid and formaldehyde (10.99), in which the degree of condensation is thought to... 

JF Lawrence, FE Lancaster. Determination of total non-sulphonated aromatic amines in food colour amaranth by dithionite reduction followed by derivatization and high performance liquid chromatography. Food Addit Contam 6(4) 415 -423, 1989. 

Raw materials. Petroleum sulphonates were originally obtained as by-products of white oil or lubricant oil production. In this process, the oil was treated with sulphuric acid, sulphonating aromatic compounds which could then be separated from the non-polar oils. These were further separated into oil soluble ( mahogany ) and water soluble ( green )... 

Toluene obtained from petroleum should contain no more than 4% of paraffinic hydrocarbons. The content of the latter is determined by sulphonation of the toluene with concentrated sulphuric acid or with 20% oleum. Sulphonated aromatic compounds are washed out with water to leave the paraffin hydrocarbon which is not affected by oleum. 

When generating arenium ions by the protonation of aromatic compounds some acid systems, along with protonation, cause some other substrate transformations. H2SO4, oleum, HSO3F and systems with these acids may sulphonate aromatic com-... 

P. Zschocke and D. Quelhnalz. Integral asymmetric, solvent-resistant ultrafiltration membrane made ol partiahy sulphonated, aromatic polyether ether ketone. DE Patent 3 321860, assigned to Berghol Eorschungsinst (DE),... 

Barsing P, Tiwari A, Joshi T, Garg S (2011) Application of a novel bacteried consortium for mineralization of sulphonated aromatic amines. Bioresour Technol 102 765-771. http //www.doi. org/10.1016/j.biortech.2010.08.098... 

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. 

The nitration, sulphonation and Friedel-Crafts acylation of aromatic compounds (e.g. benzene) are typical examples of electrophilic aromatic substitution. 

I-Naphthylamine readily diazotizes and couples to aromatic hydroxylic or basic compounds. It was thus used as a first component in a number of important monoazo dyes, but its use has been severely curtailed because of its potent carcinogenicity. It sulphonates to give naphthionic acid (l-naphthylamine-4-sul-phonic acid). 

Obtained by the catalytic hydrogenation of naphthalene. Owing to the presence of one aromatic ring it can be nitrated and sulphon-ated. It is non-toxic and is used as a solvent for fats, oils and resins. 

It is of particular interest to be able to correlate solubility and partitioning with the molecular stmcture of the surfactant and solute. Likes dissolve like is a well-wom plirase that appears applicable, as we see in microemulsion fonnation where reverse micelles solubilize water and nonnal micelles solubilize hydrocarbons. Surfactant interactions, geometrical factors and solute loading produce limitations, however. There appear to be no universal models for solubilization that are readily available and that rest on molecular stmcture. Correlations of homologous solutes in various micellar solutions have been reviewed by Nagarajan [52]. Some examples of solubilization, such as for polycyclic aromatics in dodecyl sulphonate micelles, are driven by hydrophobic... 

Aromatic nitriles (or aryl cyanides) can be obtained by methods (1) and (3). but not by method (2). In addition, aromatic nitriles can be prepared by two other methods, (a) from the corresponding diazo compound by Sandmeyer s Reaction (p. 189), (b) by fusing the corresponding sulphonic acid (or its salts)... 

A further difference between aliphatic and aromatic hydrocarbons is that only the latter are capable of direct sulphonation. Thus benzene when heated with concentrated sulphuric acid gives benzenesulphonic acid, a reaction which proceeds more readily, however, if chlorosulphonic acid is used instead of sulphuric acid an excess of chlorosulphonic acid however may convert the sul phonic acid into the sulphonyl chloride (c/. p. 181). 

Aromatic sulphonic acids are frequently difficult to obtain pure, since they almost invariably decompose on attempted distillation, and many are very soluble in water such aqueous solutions on being concentrated often give syrupy solutions from which the sulphonic acid crystallises with difficulty. 

The mechanism of aromatic sulphonation is complex and may vary, e.g. with the concentration of water or oleum in the acid, the temperature, and the hydrocarbon. One active agent is SO3, and one simplified route may be ... 

This method has the great advantage over method (A) in that it can be applied in particular to those aromatic nitriles in which the aryl group is readily sulphonated clearly, it can also be applied to nitriles in which the alkyl or aryl portion contains groups which are in any other way affected by concentrated sulphuric acid, or by concentrated aqueous alkalis. 

B) Sulphonic Acids. Simple aromatic sulphonic acids. 

C) Amino-aromatic sulphonic acids. Sulphanilic acid. 

B) SULPHONIC ACIDS. Aliphatic sulphonic acids are rarely encountered, for they are very soluble in water, and many are deliquescent. The aromatic sulphonic acids, although less uncommon, are encountered most frequently as their derivatives e.g.t the sulphonamides, pp. 247, 251), or as nuclear-substituted acids (e.g., sulphanilic acid, p. 384). 

Aromatic sulphonic acids are usually soluble in water, forming a strongly acidic solution. 

C) AMINO AROMATIC SULPHONIC ACIDS. Sulphanilic or p-amino-benzene sulphonic acid, NH2CJH4SO3H. 

These salts are by far the most readily prepared derivatives (having sharp m.ps.) of the amino-aromatic sulphonic acids. 

Amino Aromatic Sulphonic Acids. Benzylthiouronium salts (p. 384). 

Amino aromatic sulphonic acid (sulphanilic acid)... 

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