N-methylpyrrolidine preparation method

Abstract

The invention relates to preparation of organic alkalis of medical and chemical raw materials, particularly to a N-methylpyrrolidine preparation method, which comprises: a) under the catalysis of potassium iodide, carrying out a mixed reaction on 1,4-dichlorobutane and methylamine aqueous solution in an ether solvent to obtain N-methylpyrrolidine, wherein the ether solvent can form a hydrogen bondwith methylamine, and the boiling point of the ether solvent is greater than the azeotropic point of methylamine and water in the mixed system. According to the invention, the preparation method hasadvantages of abundant raw material sources and simple synthesis process route, and does not require high-pressure reaction conditions so as to achieve advantages of equipment investment reducing, production management simplifying, comprehensive cost reducing, excellent economical efficiency and wide popularization prospect compared with the high-pressure method; and the experimental results showthat with the application of the method to prepare N-methylpyrrolidine, the preparation yield is larger than 88%, and the product purity is larger than 99%.

Description

technical field [0001] The invention relates to the preparation of an organic base for medicine and chemical raw materials, more specifically, to a preparation method of N-methylpyrrolidine. Background technique [0002] N-Methylpyrrolidine is an organic base used in the manufacture of pharmaceuticals and other fine chemicals. There are five kinds of existing N-methylpyrrolidine preparation methods, wherein there are three representative preparation methods, the first method is: the catalytic hydrogenation of N-methylpyrrolidone, this method is in a high-pressure device N-methylpyrrolidone and hydrogen are reacted by catalysts such as Cr-Al or Cu-Cr under the conditions of 180-285°C / 150-280atm to prepare N-methylpyrrolidine, with a conversion rate of 85% and a selectivity of 85%. The disadvantage of this method is: the reaction is carried out under high pressure, the equipment is strictly required, and the investment is relatively large. In addition, production requires th...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is: the reaction is carried out under high pressure, the equipment is strictly required, and the investment is relatively large.

The disadvantages of this method are: the price of the main raw material tetrahydropyrrole is too high, resulting in high production costs; in addition, the consumption of formic acid, formaldehyde, hydrochloric acid, and sodium hydroxide is large, and the recovered formic acid and formaldehyde cannot be directly reused; "three wastes" Governance is difficult

The disadvantage of this method is: the main raw material tetrahydropyrrole is high, and the investment in production equipment is large.

Other preparation methods include N-methylpyrrole catalytic hydrogenation method, methyl butylamine chlorination and cyclization method to prepare N-methylpyrrolidine, these methods have expensive raw materials and complicated processes

[0003] In recent years, there are also two N-methylpyrrolidine preparation methods worthy of attention, one of which is under the catalysis of solid superacid, THF reacts with methylamine to prepare N-methylpyrrolidine. Although the raw materials of this method are easy to get, but It is necessary to prepare a super acid catalyst and perform a gas-solid multiphase reaction in a tubular reactor. It is easy to obtain satisfactory results in the laboratory, but problems are often encountered in industrial scale-up; the other is 1,4-dichlorobutane and methylamine Reaction under high pressure. Although the raw materials are cheap and easy to obtain in this method, the reaction must be carried out under high pressure, which requires high equipment and production management.

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