Method for preparing N-alkyl pyrrolidine

The present invention discloses a preparation method of N-alkyl pyrrolidine which is an intermediate used for the pharmaceutical and chemical materials. The method is that ammonia or organic amine aqueous solution is controlled at 30 DEG C, at the same time cis-1, 4-dihalogen-butylene and organic alkali or inorganic alkali solution is dripped within one to five hours, the pH value is controlled between 11 to 12, after dripping, the solution continuously reacts for one to ten hours under 30 DEG C to 100 DEG C to generate N-alkyl-3-dihydropyrrole; then organic inert solvent, the N-alkyl-3-dihydropyrrole and 5 percent of Pd/C catalyst are added into a high-pressure vessel to be heated to 30 DEG C to 100 DEG C to be led to H2O, the system pressure is controlled as 0.2 to 1.0MPa, and the N-alkyl pyrrolidine is generated after the reaction for two to twelve hours. The source of the materials of the present invention is abundant; the product has the high yield and good purity and is easy forpurifying; the requiremen