A crude product post-treatment process for the preparation of 2-amino-4,6-dimethoxypyrimidine

Abstract

The invention discloses a crude product aftertreatment new technique for preparing 2-amino-4, 6-dimethoxy pyrimidine, wherein the technique includes steps of transferring a liquid crude product of 2-amino-4, 6-dimethoxy pyrimidine in a distilling kettle by vacuum, and performing depressurization and distilling; adding pure water and stabilizer to the product acquired by distilling and cooling; heating to 75-95 DEG C and melting; then stirring while slowly cooling to 30-50 DEG C; filtering the product; drying a filter cake and acquiring a white crystal particle shaped pure product of 2-amino-4, 6-dimethoxy pyrimidine. The new technique applies easy-acquired water at lower price as the dispersing agent to replace methylbenzene, xylene and other organic solvents, reduces the solvent recycling step, and further reduces the production cost. The new technique eliminates the safety hidden trouble of low-boiling and flammable organic solvent and the environment protection pressure of volatile component which can pollute the production environment; the weak alkali type stabilizer is introduced, thus the process of generating polarity impurities from dropped methyl of 2-amino-4, 6-dimethoxy pyrimidine is effectively inhibited, thus the product quality is further promoted.

Description

technical field [0001] The invention relates to a new post-treatment process of crude product of 2-amino-4,6-dimethoxypyrimidine (ADMP), an important intermediate of medicine and pesticide. Background technique [0002] 2-Amino-4,6-dimethoxypyrimidine (ADMP) is a class of excellent pyrimidine compounds, which are widely used as various pesticide intermediates. At present, among the mainstream preparation methods of ADMP, the process route using malononitrile as raw material has been focused on, and there have been many documents on process optimization. Among them, the patent CN201510575548.3, which was applied for and published by our company in 2015, proposed an optimization Scheme: The solvent-free method is adopted in the step of aromatization and cyclization reaction, the obtained crude product is distilled in high vacuum, and then an organic solvent is introduced as a dispersant for crystallization and granulation to obtain a pure product. [0003] This solution is lo...

AI Technical Summary

Problems solved by technology

The dispersant has a certain solubility to the product, resulting in product loss. At the same time, it needs to be recycled and applied, resulting in operating costs

② There are potential safety hazards

Due to the large amount of toluene dispersant, it will volatilize and leak during use (such as product filtration, dispersant recovery and mother liquor treatment, etc.), increasing the impact of volatile organic compounds (VOC, volatile organic compounds) on the factory Environmental pollution affects the health of workers