Chlorination of n-Paraffins

Chlorination of n-paraffins (C10-C14) in the liquid phase produces a mixture of chloroparaffins. Selectivity to monochlorination could be increased by limiting the reaction to a low conversion and by decreasing the chlorine to hydrocarbon ratio. Substitution of secondary hydrogen predominates. The reaction may be represented as  

Monochloroparaffins in this range may be dehydrochlorinated to the corresponding monoolefms and used as alkylating agents for the production of biodegradable detergents. Alternatively, the monochloroparaffins are used directly to alkylate benzene in presence of a Lewis acid catalyst to produce alkylates for the detergent production. These reactions could be illustrated as follows  

Polychlorination, on the other hand, can he carried out on the whole range of n-paraffins from C10-C30 at a temperature range of 80-120°C (using a high Cl2/paraffm ratio). The product has a chlorine content of approximately 70%. Polychloroparaffins are used as cutting oil additives, plasticizers, and retardant chemicals. 

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Linear alkylbenzene sulfonates are produced from the reaction of benzene and secondary monochloroparaffins the latter are obtained by chlorination of n-paraffins. A requirement of this process was the availability of pure n-paraffins, which was made possible by the introduction of molecular sieves. The n-paraffins can be separated with molecular sieves from kerosene or gas oil, since they have a smaller diameter (ca. 4.9 A) than the branched paraffins. 

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