Preparation method of high fatty amine

The invention discloses a preparation method of a high fatty amine, and belongs to the technical field of organic compound synthesis. The preparation method comprises following steps: an alpha-halogenated aliphatic acid and a low-grade amine solution are subjected to aminolysis reaction under normal pressure or in a pressure thermal reaction kettle so as to obtain an alkyl amino fatty acid; unreacted low-grade amine is removed, an obtained product is dissolved with ethanol, and an obtained mixture is delivered into a pressure thermal reaction kettle for decarboxylation at 200 to 300 DEG C; and the high fatty amine with high purity is obtained via further purification. According to the preparation method, natural fatty acid is taken as a raw material; no expensive catalyst or complex synthetic technology is needed; the preparation method is simple; processes are low in cost, and are friendly to the environment; the novel preparation method used for synthesizing the high fatty amine is disclosed; and problems of conventional industrial fatty amine production technology that, reaction is carried out under at high temperature under high pressure with the presence of metal catalysts, reaction conditions are strict, dangerousness is high, energy consumption is high, and cost is high, are solved.