Sulphonation with sulphuric acid

As can be seen, water is set free by the reaction. The presence of water retards the sulphonation reaction, or even prevents it altogether. This is the reason why a very large excess of H2SO4 is used to bring the reaction to completion. (The oleum excess is used for the same reason.) 

Dilution, separation and neutralisation can take place in the same reactor or several batch units 

Industrial sulphuric acid sulphonation of LAB for the production of active detergents is hardly applied any more. 

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The chief advantage in the use of this acid is its selective property, whereby certain sulphonic acids are formed, which could not be formed by direct sulphonation with sulphuric acid or oleum, or which might be formed only in presence of other isomers, the separation of which might be difficult. For example, naphthalene sulphonated with oleum at the ordinary temperature gives a mixture of 1 5- and 1 6-disulphonic acids, while chlorosulphonic acid yields only the 1 5-acid. Similarly, with toluene, chiefly the ortho acid is formed. With excess of chlorosulphonic acid a sulphonyl chloride is formed, except in the case of phenols or naphthols, which give the free sulphonic acid. 

Sulphonation with sulphuric acid or oleum is initially rapid and exothermic. The rate of reaction is highly dependent on the concentration of the sulphuric acid, so the reaction slows significantly as the sulphonating agent is consumed and further diluted by the water which is a by-product of the reaction. Processes based on sulphuric acid use large excesses, resulting in high levels of waste acid or residual sulphate in the neutralised product. An alternative is to remove the water from the reaction mixture, usually by two-phase distillation, with excess substrate as a carrier. 

Styphnic acid of low purity can be obtained by sulphonating resorcinol with spent sulphuric acid or by sulphonation with sulphuric acid added with sodium nitrite according to the method of Wilkinson [31]. 

Oiling The fibre is repeatedly treated with Toumant oil (rancid olive oil). The oil has to be fixed so the textile is dried between the various oiling steps. In 1872 this procedure was optimised by the introduction of a new oil and a continuous drying process. The new oil known as Turkish red oil consisted of castor oil made soluble in water by sulphonation with sulphuric acid [13,20] Before the oiling step the cloth was steamed under an overpressure of 0.5-2 atm for a couple of hours [20]. There is no widely accepted explanation available why an oiling step improves the colour of the dyed textile [13,20]. 

For different hydrocarbons, sulphonation methods are to a large extent of the same kind. Equally with other stages and techniques of surfactant production, the methods experience an impressive progress both in implementation and technological innovations from the sulphonation with sulphuric acid and related agents [61, 62] to the present-day SO3 sulphonation processes [59, 62-65]. 

Pyrroles containing electron-attracting substituents have been sulphonated with sulphuric acid or oleum, and also chlorosulphonated 3 . 

Detergents are made by, for example, treating petroleum hydrocarbons with sulphuric acid, yielding sulphonated products which are water soluble. These can also solubilise fats and oils since, like the stearate ion, they have an oil-miscible hydrocarbon chain and a water-soluble ionic end. The calcium salts of these substances, however, are soiu u-ic in water and, therefore, remove hardness without scum formation. 

If phenol is heated with more concentrated nitric add (in the presence of sulphuric acid), nitration occurs ultimately at the para and at both the ortho positions, giving picric acid or 2,4,6-trinitrophenol. To prepare picric acid, however, it is more convenient first to heat the phenol with sulphuric acid, whereby a mixture of 0- and p-phenol sulphonic acids is readily obtained. If this mixture is now heated with concentrated nitric acid, nitration occurs at the... 

Benzenediazonium chloride reacts in solution with sodium sulphite to give benzenediazonium sodium sulphonate, which when treated with sulphurous acid undergoes reduction to phenylhydrazine sodium sulphonate. The latter readily hydrolyses in the presence of concentrated hydrochloric acid to give... 

In the sulphonation process vaporised benzene is forced through a mist of sulphuric acid at 100-120°C and the benzene sulphonic acid formed is neutralised with soda ash to produce benzene sodium sulphonate. This is fused with a 25-30% excess of caustic soda at 300-400°C. The sodium phenate obtained is treated with sulphuric acid and the phenol produced is distilled with steam (Figure 23.1). 

When azulene is heated with sulphuric acid and acetic anhydride a sulphonic acid, soluble in water, is formed. This acid forms a fine violet sodium salt. This sodium salt is not very stable when kept for three months it decomposes into a mixture of oil and resin. Its aqueous solution gives blue precipitates with calcium and barium salts. 

If acetic anhydride is employed in place of the sulphuric acid, only the sulphone is formedwhilst if nitroethane or acetic acid are employed, no oxidation at sulphur occurs. A patent has been secured for the industrial oxidation of dimethyl sulphoxide to the sulphone with nitric acid . This procedure yielded 84% of the sulphone in a continuous process which was prone to detonation at water concentrations below 14%. 

P-Bromonaphthalene. The preparation from p-naphthylamine, which has carcinogenic properties, is avoided by the use of 2-naphthylamine-1-sulphonic acid ( 2-amino-1-naphthalenesulphonic acid ) the latter is obtained commercially by cautious treatment of p-naphthol with sulphuric acid—the SOjH group first enters the 1-position—followed by the Bucherer reaction. Diazotisation and reaction with cuprous bromide yields 2-bromonaphthalene-l-sulphonic acid heating with sulphuric acid eliminates the sulphonic acid group to give 2-bromonaphthalene. 

Actually when naphthalene- jS-sulphonic acid is melted with sulphuric acid (containing water) small amounts of the isomeric a-acid are obtained. 

A combination of chomatographic techniques such as CZE-UV, ion-pair LC-DAD and ion-pair LC-electrospray mass spectrometry was employed for the separation of polar hydrophilic aromatic sulphonates. SPE preconcentration of aromatic sulphonates was studied in detail. Sorbents LiChrolut EN, Isolute ENV+, HR-P and Oasis HLB were included in the experiments. They were activated by rinsing 7 ml of methanol followed with 3 ml of water acidified to pH 2.5 with sulphuric acid. Water samples were passed... 

Sulphonation Aniline reacts with concentrated sulphuric acid to form anlllnlum hydrogensulphate which on heating with sulphuric acid at 453-473K produces p-amlnobenzene sulphonlc acid, commonly known as sulphanlkc acid, as the major product. 

Electrolytic processes for the perchlorates.—F. von Stadion found that if an aq. soln. of chlorine dioxide be included in Volta s circuit, at first very little gas is developed, but after some hours, oxygen and chlorine appear at the anode, and hydrogen at the cathode. The volume of hydrogen so obtained is nearly twice that of the oxygen. After some time the soln. is decolorized, and transformed into perchloric acid. In 1857, A. Riche 18 prepared perchloric acid by the electrolysis of hydrochloric acid, or of an aq. soln. of chlorine and ten years earlier, H. Kolbe prepared potassium perchlorate by the electrolysis of an aq. soln. of potassium chloride—acidified with sulphuric acid—and of potassium trichloro-methyl-sulphonate. H. Kolbe (1846), a pioneer in the electrolytic preparation of compounds, specially noted that the formation of perchloric acid is always preceded by that of chloric acid, and stated ... 

The following methods are available for the preparation of chloro-sulphonic acid (1) The substance can be obtained by the gradual action of moisture (e.g. atmospheric moisture) on sulphuryl chloride a similar reaction occurs with sulphuric acid and is more easily regulated ... 

Naphthylamine is no longer manufactured and its laboratory preparation should never be attempted because of its potent carcinogenic properties. For many preparative purposes (e.g. see 2-bromonaphthalene, cognate preparation in Expt 6.72, and 2-naphthoic acid, Expt 6.154), 2-naphthylamine-l-sulphonic acid may be used. This is obtained commercially by cautious treatment of 2-naphthol with sulphuric acid - the sulphonic acid group entering the 1-position - followed by a Bucherer reaction. 

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 )... 

In practice, the process is effected as follows, Crude m- xylene, containing 60-70% of m- xylene, is mixed with sulphuric acid (sp. gr. 1.84) whereupon the temperature rises to 45°C. Then the mixture is heated to 50°C and allowed to remain at this temperature for 2 hr. Under these conditions sulphonation of the o- and m- isomers takes place. The sulphonic acids may be separated from unconverted p- xylene either by extraction with water or by expelling the p- xylene by steam distillation. 

Sulphonic Acids.—(b) The same is true in regard to the reaction of the benzene hydrocarbons with sulphuric acid. Substitution products are formed directly, and are known as sulphonic acids, CeHg—SO2OH, benzene sulphonic acid. 

The silicol formed gives with sulphuric acid a mixture of sulphonic acids, one of which has been isolated as the ammonium salt. It is found... 

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