Sulphonation process

At one time the requirement for phenol (melting point 41°C), eould be met by distillation of eoal tar and subsequent treatment of the middle oil with eaustic soda to extraet the phenols. Such tar acid distillation products, sometimes containing up to 20% o-cresol, are still used in resin manufacture but the bulk of phenol available today is obtained synthetically from benzene or other chemicals by such processes as the sulphonation process, the Raschig process and the cumene process. Synthetic phenol is a purer product and thus has the advantage of giving rise to less variability in the condensation reactions. 

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). 

The benefits of the cerium methane sulphonic process are [132] (1) low cost, (2) methane sulphonic acid is unreactive with reactants and products, (3) stable to anodic and Ce(IV) oxidations, (4) high solubility of both Ce(III) and Ce(IV),... 

Sulph(on)ation processes. Since many of the anionic surfactants to be discussed are made by the addition of S03 to an organic substrate, it is appropriate to consider, in overview, the main processes used and the contribution of the sulphonation process to the quality and performance of the surfactant. (The term sulphonation is used here generically to describe reaction of an organic with SO3, regardless of the nature of the substrate.)... 

The properties of the two species are very different in terms of their solubility, viscosity and detergency. The alkene sulphonate is the better performing surfactant and the manufacturing process is developed to maximise this more desirable product. The sulphonation process is significantly more exothermic than LAB sulphonation, requiring careful control of reactor temperatures and more dilute S03 which often results in lower reactor loadings and hence lower productivity, compared to LAB. Low product colours can be achieved but require very careful control of sulphonation, neutralisation and hydrolysis. Earlier processes relied heavily... 

It has been proved that carrying out the reaction in two stages, as described above, makes the sulphonation process proceed more quietly and prevents the S03H group from entering position 7 (otherwise, the sulpho group in position... 

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]. 

In the detergent industry sulphonation processes with sulphuric acid, oleum and SO3-complexes are essentially of historical significance, and are not any longer used in developed countries. In the production of white oils, however, sulphonation with concentrated sulphuric acid and oleum is still used. The sulphuric acid treatment of selected petroleum fractions lead to petroleum sulphonates the sodium or ammonium salts of which are used in tertiary oil recovery, metallurgy, froth flotation and concrete industry, while the magnesium, calcium and barium salts are used as dopes in fuels and lubricants. The sulphonation with chlorosulphonic acid continue to remain useful in batch processes, typically on a relatively small scale ... 

A BRIEF DESCRIPTION OF THE SULPHONATION PROCESSES USED FOR THE MANUFACTURE OF ACTIVE DETERGENTS... 

Bozzetto (Bergamo, Italy) offers a continuous chlorosulphonic acid sulphonation process which comprises two water-jacketed glass vessels for sulphonation and neutralisation, and a HCl absorption column. Organic feedstock and chlorosulphonic acid are mixed on a rotating disc. Under the centrifugal action of the disc, the reaction mixture is sprayed as a thin film on to the wall of the reaction vessel. The acid product falls to the base of ihe reactor and then onto a similar rotating disc system, where it is mixed with alkali and sprayed onto the wall of the neutralisation vessel. The unit is operated under slightly reduced pressure to remove HCl gas... 

The sulphonation process conditions are summarised in table 38. Table 38 Summary of sulphonation process conditions... 

The sulphonation process is the oldest (1890) of the commercial phenol syntheses. Whilst it is still in use, it is essentially obsolete because of the requirement of auxiliary chemicals and formation of valueless by-products. 

As in the sulphonation process, use is made of various by-products in subsequent operations. This is shown by the following equations ... 

This process will also provide a new direction to sulphonation processes using liquid sulphur dioxide and liquid sulphur trioxide. 

Dodecylbenzene-sulphonation process for producing alkylaryl sulphonate (reactor 8). 

Table 13 gives data concerning the sulphonation process. 

Yields of the products in the dodecylbenzosulphonate-sulphonation process in one cycle (reactor S)... 

Figure 2. Sulphonation process of the trans ethene bridged PMO.

The trans ethene bridged PMOs are sulphonated with chlorosulphonic add and are characterized with nitrogen adsorption desorption experiments. The characteristics of the E-ePMO and the E-ePMO-SOsH are presented in Table 1. The sulphonation process has no great influence on the porosity of the material. Only a slight increase in Sbet occurs after the treatment with chlorosulphonic add. 

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