Patent ID: 7208118

Claim:
A process for preparing compounds of the formula (1) where A is C 2 - to C 4 -alkylene, B is C 1 - to C 4 -alkylene, n is a number from 1 to 100, and R is C 1 - to C 30 -alkyl, C 2 - to C 30 -alkenyl, or C 6 - to C 30 -aryl, by a) alkylating a basic mixture of oxoalkylated alcohols of the formula R—O-(-A-O—) n —H and alkoxides thereof with a C 2 - to C 5 -chlorocarboxylic acid in the absence of a solvent, b) converting the thus obtained ethercarboxylic acid salt to the free ethercarboxylic acid by adding an acid, the pH being adjusted to 3 or less, c) freeing the thus obtained ethercarboxylic acid, without washing, of water present down to a residual water content of <0.30% by distillation under reduced pressure, and d) removing the precipitated metal salts by filtration, so that the resulting product has a residual salt content of <0.2%.