Process for preparing 4-amino-N, N-dimethylbenzylamine

Abstract

The invention provides a process for preparing 4-amino-N,N-dimethylbenzylamine. The process comprises the steps of: (1) adding solutions of 4-nitro benzyl bromide or 4-nitro benzyl bromide in an organic solvent in batches into an organic solvent containing dimethylamine and triethylamine to obtain 4-nitryl-N,N-dimethylbenzylamine, wherein the single batch feeding amount of 4-nitro benzyl bromide and the molar percentage of dimethylamine in the reaction system are smaller than 7 percent; (2) reducing 4-nityl-N,N-dimethylbenzylamine by using a reducing agent to obtain 4-amino-N,N-dimethylbenzylamine. According to the process, the side reaction mechanism and the effective control method of a new impurity bis(nitrobenzyl)-dimethyl ammonium bromide are studied, the reaction conditions are optimized, the entire process is simple and easily implemented, and the purity and yield of the product are high; and the process is suitable for industrial production.

Description

technical field

[0001] The invention belongs to the field of organic chemical synthesis, and in particular relates to a preparation method of 4-amino-N,N-dimethylbenzylamine. Background technique

[0002] 4-Amino-N,N-dimethylbenzylamine is an important compound. As an intermediate of dyes, pesticides or medicines, it requires high purity and can be produced industrially. Its structural formula is as follows:

[0003]

[0004] About the preparation method of 4-amino-N,N-dimethylbenzylamine, existing literature reports have:

[0005] US5852030A discloses that 4-nitro-N,N-dimethylbenzylamine is reduced in methanol through platinum hydroxide catalytic hydrogenation or in ethanol through stannous chloride reduction to obtain 4-amino-N,N-dimethyl benzylamine.

[0006] US6166006A discloses: adding an aqueous solution of dimethylamine to a tetrahydrofuran solution of p-nitrobenzyl bromide at 0°C, reacting for 60 hours, and purifying by column chromatography to obtain 4-nitro-N...

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