The Action of Sulphuryl Chloride on Wool

Abstract

Sulphuryl chloride is known to make wool unshrinkable by canning disulphide bond breakdown in the surface scale structxire of the fibres. It has now been found that the aotion of sulphuryl chloride on commercial flannel is seriously impaired when residual oil and soap are removed by extraction with ether and alcohol. High reactivity with sulphuryl chloride can, however, be restored if sodium oleate or oleic acid, but not stearic acid, is added to the purified fabric from solution in alcohol. Within the limits of the experimental error, all the oleic acid added in this way can be removed by extraction with carbon tetrachloride without causing any serious fall in reactivity. It is obvious, therefore, that oleic acid does not itself promote the reaction between sulphuryl chloride and wool, but is the source of some substance, present in small quantity, which is the active compound. The latter can be isolated by extracting the fabric with alcohol, after first removing the oleic acid with carbon tetrachloride. When the alcohol extract is applied to a purified fabric, high reactivity with sulphuryl chloride is again observed.These observations suggest that the active compound in oleic acid is an organic peroxide, and con. firmation has been found in the fact that benzoyl peroxide has the same effect as oleic acid when applied to purified wool from alcoholic solution. By analogy with the chlorination of alkyl groups with sulphuryl chloride in presence of organic peroxides, it is believed that the latter assist the reaction between sulphuryl chloride and the disulphide bonds of wool by initiating reaction chains involving free chlorine atoms. If, therefore, peroxides are deliberately introduced into wool before treatment with sulphuryl chloride, the rate of reaction should be high enough to make continuous processing possible.