Hoechst Aktiengesellschaft

Clariant Finance (bvi) Limited

Guillermo Maier

Klaus Raab

Rudolf Aigner

Hubert Seitz

Rainer Muller

A process is described for the preparation of aqueous solutions of betaines of the formula ##STR1## in which: R.sup.1 is an alkyl radical having 6 to 22 carbon atoms or is a radical of the formula R'CONH(CH.sub.2).sub.z --, in which R' has the meaning of R.sup.1 and z is 2, 3 or 4, R.sup.2 is an alkyl radical having 1 to 4 carbon atoms or is a radical of the formula --(CH.sub.2).sub.m --OH, in which m is 1, 2 or 3, R.sup.3 is an alkyl radical having 1 to 4 carbon atoms or is a radical of said formula --(CH.sub.2).sub.m --OH and y is 1, 2 or 3. The aqueous betaine solutions are prepared by quaternization of the corresponding tertiary amines with an .omega.-halocarboxylic acid and with an alkali metal hydroxide in the aqueous phase. The quaternization is carried out continuously in two or three stirred tanks arranged in a cascade, defined process characteristics being maintained in each tank. Using the novel process, aqueous betaine solutions are obtained in high yield and purity in a simple manner.

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Haiming, Germany

Guillermo Maier