The invention belongs to the technical field of
fine chemical engineering, and particularly relates to a preparation method of tetramethylguanidine, which comprises the following steps: step 1, reacting
cyanogen chloride with
dimethylamine at low temperature in a tubular reactor to generate dimethylamino
cyanogen and
dimethylamine hydrochloride, step 2, heating intermediates of the dimethylamino
cyanogen and the
dimethylamine hydrochloride, and reacting to obtain the tetramethylguanidine. The method comprises the following steps: 1, adding a
sodium hydroxide aqueous solution into a reaction solution, carrying out heat preservation on the reaction solution after adding a catalyst, and carrying out high-temperature condensation to generate tetramethylguanidine
hydrochloride, 3, cooling the product, filtering to obtain tetramethylguanidine hydrochloride, and washing the tetramethylguanidine hydrochloride with a detergent, and 4, carrying out a
neutralization reaction on the
sodium hydroxide aqueous solution and tetramethylguanidine hydrochloride to obtain the tetramethylguanidine hydrochloride. And extracting the reaction solution by using an
organic solvent, and fractionating to obtain free tetramethylguanidine. The catalyst is added in the reaction process, so that the temperature required by the reaction is reduced, the time required by the reaction is shortened, a
continuous flow process is realized, and the productivity is remarkably improved.