A process for preparing duennfluessiger imidazolinium by quaternization of 1-hydroxyethyl-2-alkyl imidazolines

A process is disclosed for producing fluid imidazolinium tensides by reaction of 1-hydroxyethyl-2-alkylimidazolines with neutralized quaternary agents and hydrolysis of the quaternary products thus obtained with aqueous bases. The 1-hydroxyethyl-2-alkylimidazolines are added at a high temperature to an aqueous solution of the neutralized quaternary agents at a molar proportion between imidazoline derivates and the quaternary agents from 1:1.5 to 1:3. The reaction mixture thus obtained is maintained at a temperature in a range of 70 to 85 DEG C for 30 to 120 minutes, 0.85 to 1.0 mol alkali metal hydroxides, referred to the amount of quaternary agents added during step (a), are added thereto within the 30 to 120 minutes at a temperature in the range of 75 to 85 DEG C, and the reaction mixture thus obtained is maintained at a temperature in the range of 75 to 90 DEG C for 140 to 220 minutes. The end products are obtained by a process that is easy to carry out if during step (a) a solution of neutralized quaternary agents is used that contains 0.025 to 0.5 mol of carboxylic acids, referred to the amount to be added of 1-hydroxyethyl-2-alkylimidazolines, and if acids are added to the reaction mixture obtained during step (d), so that when the reaction mixture is diluted with water up to a 10 wt% concentration of the product, a pH value in the range of 7 to 10 is set.