Preparation method of diethylene monoisopropanolamine

The invention relates to a preparation method of diethylene monoisopropanolamine. The preparation method comprises the following steps of (1) introducing an inert gas to replace air inside a reaction kettle into the reaction kettle; (2) premixing epoxy propane and diethanolamine, then adding to the reaction kettle, introducing the inert gas to keep the pressure inside the reaction kettle to 0.1-0.5 Mpa, stirring and mixing materials, then raising temperature, keeping the temperature, and reacting to obtain a diethylene monoisopropanolamine product. According to the preparation method disclosed by the invention, diethanolamine and epoxy propane are utilized as raw materials and the conventional way of taking water as a solvent is abandoned, and the materials are premixed, so that the viscosity and solidification point of the reacted materials are reduced; the fast progress of reaction is facilitated due to the uniform dispersion of the two materials in a reactor; in addition, under the condition of low alkane-amine ratio, the improvement of the utilization ratio of epoxy propane and the reduction of generation probability of side reaction are facilitated. The whole process has the advantages of low energy consumption, high material transformation rate, high product purity, stable quality and no wastes.