The invention discloses a
lauryl betaine preparation method, which comprises: 1, preparing
sodium monochloroacetate: adding 30-40 g of
monochloroacetic acid into a three-neck flask provided with a
thermometer and a stirrer, adding a proper amount of water to dissolve, uniformly stirring, slowly adding 240-280 g of a 20% alkaline solution into the
monochloroacetic acid solution, stirring while controlling the pH value to be 6.5-7.0, and carrying out a reaction for 2-3 h to obtain
sodium monochloroacetate; the
reaction temperature is controlled below 60 DEG C until the
neutralization is complete; 2, 60-75 g of dodecyl dimethyl
tertiary amine is added into the
sodium monochloroacetate solution to ensure complete
dissolution, the temperature of a
reaction system is controlled to range from 60 DEG C to 85 DEG C to react for 5-12 h in an
oil bath provided with a temperature controller, 50 ml of 80%
ethanol solution is added, and full stirring is conducted; 3, after the reaction is completed, the solution is naturally cooled to the
room temperature. Filtering, washing and
drying to obtain
lauryl betaine, and distilling to obtain purified
lauryl betaine. By coordinating the specific
reaction conditions and process in the preparation process, the content of active substances in lauryl
betaine is high, and the appearance reaches the standard.