Patent GB-672114-A (GB)
Title: Improvements in or relating to sulphonation processes
IPC: C07C303/10
Filed: 1948-02-28
Abstract: In a process for the sulphonation of a saturated aliphatic or cycloaliphatic liquid hydrocarbon the hydrocarbon is either (a) treated with sulphur dioxide and aqueous hypochlorous acid or chlorine monoxide or a solution obtained by agitating a fully chlorinated hydrocarbon with aqueous hypochlorous acid or by saturating a fully chlorinated hydrocarbon with chlorine monoxide or (b) emulsified with sulphuric acid and treated with a hypochlorite (e.g. bleaching powder).  In process (a) it is preferred to agitate the hydrocarbon with aqueous hypochlorous acid or chlorine monoxide first and then to introduce the sulphur dioxide.  When employing a fully chlorinated hydrocarbon as vehicle it is preferred to use carbon tetrachloride containing hypochlorous acid, chlorine monoxide and chlorine obtained by agitating aqueous hypochlorous acid and carbon tetrachloride and removing the aqueous phase.  The products are treated with organic or alkali metal bases to yield the corresponding sulphonates.  The products have wetting, cleaning, dispersing, levelling, or sudsing properties and may be employed in wetting or detergent compositions of matter.  In examples: (1) Pool paraffin is agitated with aqueous hypochlorous acid prepared by treating sodium hypochlorite with nitric acid, the oily layer is reacted with sulphur dioxide and sodium sulphonates are obtained by treating the product with caustic soda.  The process may be operated continuously, unreacted oil being returned to the first stage; (2) cetane and sulphuric acid are emulsified and bleaching powder is added.  The product is diluted and treated with lime and soda to obtain a detergent liquor; (3) pool paraffin, pretreated with sulphuric acid and washed with water, is treated with a carbon tetrachloride extract from sodium hypochlorite solution to which nitric acid has been added and sulphur dioxide.  The carbon tetrachloride is distilled off under reduced pressure and the residual liquid is treated with aqueous sodium hydroxide to neutralize sulphonic acids and hydrolyse sulphochlorides; (4) pool paraffin, pretreated with sulphuric acid, is treated with sulphur dioxide and a solution of chlorine monoxide in carbon tetrachloride. The products are treated as in example (3) after removal of the carbon tetrachloride.  The Provisional Specification describes the reaction of a saturated or unsaturated hydrocarbon or carboxylic acids or esters derived therefrom with a hypohalous acid or anhydride or salt thereof and sulphuric acid or sulphur dioxide.  Phenol may be added prior to the treatment with sulphuric acid; sodium bisulphite under pressure may be employed instead of sulphuric acid, and air or oxygen may be passed through the reactants. Hypochlorous acid may be generated in situ by blowing through a mixture of the hydrocarbon and alkali metal hypochlorite a stream of carbon dioxide or of an acid which will not cause the decomposition of hypochlorous acid, e.g. dilute nitric acid.  To ensure an intimate dispersion of all phases of the reactants a venturi tube device, e.g. in conjunction with agitating means may be employed.  In example (2) a liquid hydrocarbon fraction containing saturated aliphatic hydrocarbons of average chain length thirteen carbon atoms is forced into aqueous hypochlorous acid and the oily layer is removed and treated with sulphur dioxide in countercurrent.  The product is extracted with aqueous caustic soda and further treated with hypochlorous acid.  The specific gravity of the hypochlorous acid can be increased by the addition of an inert salt, e.g. calcium nitrate.