| abstract |
A process is described for the preparation of aqueous solutions of betaines of the formula <IMAGE> in which: R1 is an alkyl radical having 6 to 22 carbon atoms or is a radical of the formula R'CONH(CH2)z-, in which R' has the meaning of R1 and z is 2, 3 or 4, R2 is an alkyl radical having 1 to 4 carbon atoms or is a radical of the formula -(CH2)m-OH, in which m is 1, 2 or 3, R3 is an alkyl radical having 1 to 4 carbon atoms or is a radical of said formula -(CH2)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. |