Abstract: Automatically controlled process for the neutralization of soap solutions in which an acid is mixed with the soap solution just before or as said soap solution enters a reaction zone, in which turbulent flow conditions are maintained, the relative amounts of acid and soap solution being controlled via a signal derived from the measurement of the pH of the turbulent reaction mixture, and the ratio of the total dead time to the mean residence time of the reaction mixture in the reaction zone is less than unity.This process allows a stable content of the neutralization while using a low excess of acid, hence providing savings in chemicals, labor and oil losses, and reducing effluent problems.