A) Take o-phenylenediamine, glycine and 5~6mol/L HCl, sequentially added to the flask, in which the molar ratio of o-phenylenediamine and glycine is 1:1-3, 1:1.5-2.5; the molar ratio of o-phenylenediamine and 5~6mol/LHCl is 1:10-12. stirred uniformly, put into the microwave oven of the frequency of 2450MHz at an output power of 119W and irradiated intermittently for 6 times, 1min each time, to make the total solution.
B) the whole solution in the microwave oven at an output power of 119 ~ 280W intermittent irradiation 10 times, each time the irradiation of 4 ~ 6min after an interval of 10min. cooling, precipitation of solids, filtration, anhydrous ethanol washed, drying to obtain the crude product.
C)The crude product was recrystallized with anhydrous ethanol to obtain 2-aminomethylbenzimidazole dihydrochloride, which was dissolved in water, adjusted pH to 8~9 with ammonia, cooled to 3~5 to make the crystallization complete, and recrystallized with ethanol/water to obtain 2-aminomethylbenzimidazole, with a maximum yield of 77%. 2-aminomethylbenzimidazole further reacted with hydrochloric acid to form 2-(aminomethyl)benzimidazole dihydrochloride
