Hydrochloric Acid → 1,4-Dimethylpiperazine dihydrochloride

A 5000 ml four-neck round-bottom flask equipped with a reflux condenser, mechanical stirrer, thermometer and a dropping funnel was charged with 1198.5 g (5.0 moles) of a 47.6 percent aqueous solution of 1,4-dimethylpiperazine. The solution was cooled by means of an ice-water bath and 985.5 g (10.0 moles) of 37 percent hydrochloric acid was added at such a rate as to keep the temperature below 45° C. To the well-agitated 1,4-dimethylpiperazine dihydrochloride solution so obtained, 925.2 g (10.0 moles) of epichlorohydrin was added slowly, again at such a rate as to keep the temperature below 45° C. After the addition was completed, the temperature of the reaction mixture was raised to between 60° and 70° C. for 30 minutes, followed by another hour at 100° C. A 59.8 percent solution of N,N'-dimethyl-N,N'-bis(3-chloro-2-hydroxypropyl) piperazinium dichloride was obtained.