Hoechst Aktiengesellschaft

Rainer Muller

Rudolf Aigner

Hubert Seitz

Horst Reuner

Gunther Muller

Guillermo Maier

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.

Process for the preparation of aqueous betaine solutions

A process for the preparation of sulfated alkanol oxethylates or alkylphenol oxethylates is described. After completion of the reaction with SO.sub.3, 0.1 to 0.5% by weight, relative to the alkanol oxethylates or alkylphenol oxethylates employed, of at least one of the following compounds: water, ethanol, 1-propanol, 2-propanol or n-heptane are admixed to the reaction mixture and liquid and gas are subsequently separated at a temperature of 20.degree. to 60.degree. C. The liquid is then neutralized with aqueous alkali as customary and leads to ether sulfate/water mixtures with considerably reduced contents of 1,4-dioxane which can either be used without further aftertreatment or with a considerably reduced outlay in terms of aftertreatment as personal hygiene agents and for various other purposes.

Growing community of inventors

Burghausen, Germany

Rainer Muller