Method for producing 2-(1-cyclohexenyl)ethylamine

Abstract

The invention provides a method for producing 2-(1-cyclohexenyl)ethylamine. The method comprises the following steps: S1, controlling reaction pressure of 1-cyclohexeneacetonitrile, a solvent, a catalyst and liquid ammonia to be 1.5 to 5.5MPa in the presence of hydrogen gas and reacting at 55 to 130 DEG C until the consumption amount of the hydrogen gas is 90 to 95 percent of the theoretical consumption amount; S2, under the condition that the temperature is not changed, reducing the adding amount of the hydrogen gas; reducing the reaction pressure to 1.0 to 3.0MPa; continually reacting untilthe consumption amount of the hydrogen gas is 102 to 110 percent of the theoretical consumption amount; stopping adding the hydrogen gas and cooling to 50 DEG C or lower; then finishing the reaction.According to the method provided by the invention, a Raney nickel catalyst with a cheap price is used for catalyzing the 1-cyclohexeneacetonitrile to be hydrogenated to prepare the 2-(1-cyclohexenyl)ethylamine. The precision of a hydrogenation process is controlled so that the generation of double-bond reduction side reaction is reduced and the utilization rate of raw materials is improved to thegreatest extent; finally, advanced technical indexes that the purity of a product is greater than 99 percent and the separation yield is greater than 80 percent are realized, and the method is very good for industrial production.

Description

technical field [0001] The invention relates to a method for producing 2-(1-cyclohexenyl)ethylamine, belonging to the technical field of fine chemicals. Background technique [0002] 2-(1-cyclohexenyl)ethylamine, English name: 2-(1-Cyclohexenyl)ethylamine, CASNo.: 3399-73-3, is the basic raw material of the antitussive drug dextromethorphan. Dextromethorphan has been recorded in the pharmacopoeias of many countries. There is no industrial production in my country at present, and all raw materials rely on imports. Therefore, it is the key development variety in this field in our country. [0003] Industrial production of 2-(1-cyclohexenyl)ethylamine is obtained by catalytic hydrogenation of 1-cyclohexene acetonitrile. However, in the reaction, the double bond of the raw material 1-cyclohexyl acetonitrile also undergoes a hydrogenation reaction to generate by-products such as 2-cyclohexylethylamine and 2-cyclohexyl acetonitrile. The specific reaction equation is as follows: ...

AI Technical Summary

Problems solved by technology

However, after the catalyst poisoning activity of this method is reduced, the main reaction rate of cyano group reduction to amino group is also reduced.

In the best implementation example 1 of this patent, the conversion rate of raw materials is 83.4%, the selectivity of 2-(1-cyclohexenyl)ethylamine is 86.7%, and the single-pass reaction yield is only 72.3%, which is not higher than Suzhou Ai Significantly improved yields as stated in Medicinal Chemicals patents

In addition, the deactivation rate of the palladium carbon catalyst treated with sulfur poisoning is very fast, and the number of repeated applications is not much. If the palladium carbon catalyst needs to be replaced frequently, the method is also difficult to apply to industrial production in terms of cost.

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