Synthesis method of N-methylisopropylamine

Abstract

The invention relates to the field of preparation of pesticide and medical intermediates, in particular to a preparation method of N-methylisopropylamine. The method comprises the following steps: taking isopropylamine as a raw material, taking dimethyl carbonate as a reaction solvent, and carrying out heat preservation reaction under the catalysis of a basic catalyst; and after the reaction is finished, filtering to remove the catalyst, carrying out rectification separation on filtrate, and separating the solvent dimethyl carbonate from the product. The method effectively controls the generation of a byproduct disubstituted N, N-dimethyl isopropylamine, and effectively controls the conversion rate and selectivity of raw materials, and compared with the prior art, the novel synthesis method of N-methyl isopropylamine has the following effective effects: the raw materials are easy to obtain, the reaction is mild, the reaction steps are simple, the cost of the raw materials is lower, the selected solvent dimethyl carbonate is relatively low in toxicity and can be recycled, so that the product is a green chemical product with a development prospect, and the method is extremely low in three-waste amount and relatively great in industrial application prospect.

Description

technical field [0001] The invention belongs to the field of preparation of pesticides and pharmaceutical intermediates, in particular to a method for synthesizing N-methylisopropylamine. Background technique [0002] N-methylisopropylamine, also known as N-methylisopropylamine or N-isopropylmethylamine, is a colorless liquid and is an important pharmaceutical intermediate. Pain agent) to the main raw material. [0003] Specifically, the synthetic method of N-methylisopropylamine has a lot, according to different reaction routes, can be divided into following several kinds: [0004] ①Patent No. CN102070461A discloses a preparation method for synthesizing N-methylisopropylamine from isopropylamine. The patent makes N-methylisopropylamine through two steps of Mannich reaction and decomposition reaction. According to the disclosed content of the patent, No. The yield of the one-step Mannich reaction is 85.9%, and the yield of the second step decomposition reaction and subsequ...

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Problems solved by technology

[0004]①Patent No. CN102070461A discloses a preparation method for synthesizing N-methylisopropylamine from isopropylamine, which is a two-step process of Mannich reaction and decomposition reaction N-methylisopropylamine, according to the content disclosed in this patent, the yield of the first step Mannich reaction is 85.9%, the second step decomposition reaction and subsequent rectification, the yield is only 50%-60%, The synthesis process of this invention is relatively complicated. The first step is the Mannich reaction, the reaction conditions are harsh, the effective content and the yield are low, the second step of the synthesis is the decomposition reaction, and the reaction produces a large amount of hydrochloric acid wastewater, and the price of zinc powder is relatively expensive. The acid contains a large amount of p-zinc chloride, the treatment of the three wastes is more complicated, and the equipment is more corrosive

[0012] The above four routes belong to the methylation reaction and have their own disadvantages, but they have a common disadvantage, which is to produce disubstituted N,N-dimethyl Isopropylamine and a small amount of polymer cannot meet the conversion rate and selectivity of raw materials at the same time. Because the by-product N,N-dimethylisopropylamine is very similar in nature to the product, it is very difficult to separate it. Therefore, a A kind of synthetic N-methylisopropylamine that can be selectively, avoids the synthetic method of the N-methylisopropylamine that dimethyl replaces

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