Process for the manufacture of sulfobetaines

A process for preparing a sulfobetaine of formula I ##STR11## wherein R.sub.1 is hydrogen, straight-chained or branched alkyl groups of 1 to 22 carbon atoms, hydroxyalkyl, or aralkyl,

• R.sub.2 is an alkyl group as indicated for R.sub.1, provided that R.sub.1 and R.sub.2 may be the same or different or together form a closed ring, and
• R.sub.3 is an alkyl group of the formula CH.sub.3 --(CH.sub.2).sub.n --where n=0 to 25 branched alkyl groups, hydroxyalkyl groups, or substituted alkyl groups,
• wherein an alkylammonium salt of the general formula IV ##STR12## wherein R.sub.1, R.sub.2 and R.sub.3 have the same definition as above, and X is fluoride, chloride, bromide, methosulfate or an equivalent sulfate, equivalent sulfite, and equivalent phosphate, is reacted with at least one salt of sulfurous acid, in a solution at a pH of 2-9, at a temperature from 0.degree. C. to 100.degree. C., and in the presence of at least one transition metal ion of the first, fifth, seventh, or eighth secondary group of the Periodic Table of the Elements and at least one initiator.