The invention belongs to the technical field of
feed additive and relates to a method for preparing
betaine hydrochloride, which comprises the following steps: a, adding
ethyl chloroacetate and
methanol or isopropanol into the reactor, stirring uniformly and cooling the mixture; b, introducing
trimethylamine anhydrous gas into the mixture, fully stirring after the
trimethylamine anhydrous gas is introduced completely, filtering, recrystallizing collected
solid product,
drying under vacuum and obtaining 2-ethoxy-2-oxa-N,N,N-trimethyl-ethylammonium
chloride; and c, adding 2-ethoxy-2-oxa-N,N,N-trimethyl-ethylammonium
chloride and diluted
hydrochloric acid into the reactor to obtain
mixed solution, heating, reacting with stirring, distilling after reaction, filtering,
drying collected
solid product under vacuum, and thus, obtaining the refined
betaine hydrochloride. In the invention, the reactions in the steps are normal operation, the safety of production is ensured, the need of using expensive
raw material is obviated, the production cost is reduced, the final product does not contain
sodium chloride, and the requirements of some special fields are met.