46results about How to "High purity requirements" patented technology

The invention relates to the technical field of purification of p-phenylenediamine, in particular to a purification method of high-purity p-phenylenediamine. The purification method specifically comprises the following steps: S1, adding water into a p-phenylenediamine crude product, mixing, and stirring at high temperature to form a uniform solution; s2, cooling and crystallizing the solution to obtain crystals and crystallization mother liquor; s3, heating and melting the crystals to obtain molten liquid; and S4, rectifying the molten liquid to obtain the high-purity p-phenylenediamine and a rectification residual liquid. According to the purification method, only water is used as a solvent, the method is simple, and the problems that an organic solvent used in a traditional method is high in cost and has environmental protection and potential safety hazards are solved; according to the purification method, the high-purity requirement of the crystallized product can be met by precisely controlling the adding amount of the solvent water, high-precision temperature control equipment in a traditional method is not needed, automation is easy to achieve, and the purification method is suitable for industrial production.