Method for producing N-alkyl-(3,4-methylenedioxy) aniline

Abstract

A preparation method of N-alkyl-(3, 4-methylenedioxy) aniline relates to the method of the N-alkyl-(3, 4-methylenedioxy) aniline. 3, 4-(methylenedioxy) nitrobenzene in a pressure kettle is taken as the starting raw material, C1 to C4 lower aliphatic alcohols are taken as reaction solvents and alkylation reagents, a reductive alkylation catalyst is added, the pressure kettle is sealed, hydrogen gas is introduced for replacement, the temperature is increased, the hydrogen is introduced, the hydrogenation reaction is finished, the temperature is decreased, the pressure is relieved, then the N-alkylation reaction, the nitrogen introducing for replacement and the temperature increase reaction are continuously carried out for preparing the N-alkyl-(3, 4-methylenedioxy) aniline. In the preparation method, the hydrogenation reduction and the N-alkylation reaction are carried out in a same reaction kettle, the reduction products do not need to be separated, aldehyde and ketone alkylation reagents do not need to be added, and the N-alkylation reaction is directly carried out. The preparation method has small environmental pollution, good N-alkylation selectivity and high conversion rate, the raw material is easy to be recovered, the catalyst can be applied, the production cost is low, and the production process can be simplified.

Description

technical field [0001] The present invention relates to a process for N-alkyl-(3,4-methylenedioxy)anilines. Background technique [0002] At present, there are mainly two methods for synthesizing N-alkyl-(3,4-methylenedioxy)aniline both at home and abroad: one is as described in European Patent EP0549263, using 3,4-methylenedioxybenzene and Bromination with hydrobromic acid, followed by ammoniation reaction with ammonia water in an autoclave to obtain N-ethyl-(3,4-methylenedioxy)aniline. This method has the disadvantages of "three wastes" pollution, troublesome post-treatment, difficult separation of target products, low yield, and difficult recovery of raw materials. Hydrobromic acid is easy to corrode equipment, and alkane ammonolysis requires high temperature and pressure, so the requirements for equipment are very high. [0003] The other is the hydrogenation reduction method, generally 3,4-(methylenedioxy)nitrobenzene is first hydrogenated and reduced under the cataly...

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Problems solved by technology

However, the alkylation reaction still needs to be carried out under the condition of hydrogen and pressure, and an additional alkylating agent is required, so the operation is still cumbersome

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