A method for separating pyridine derivatives in the production of prazole

Abstract

The invention relates to a separation method of pyridine derivatives in prazole production, belonging to the technical field of chemical separation. The separation method comprises the specific steps of (1) separating crude products of pyridine derivatives, namely after reactions of nitridation and oxidation or nitrification or chlorination or etherification in the step of prazole production, adding pure water with proper proportion, regulating pH of a water layer and an organic layer in the system, adding an organic solvent for extraction, and carrying out normal-pressure fractionation to separate out unreacted crude products of the pyridine derivatives; and (2) carrying out decompressed distillation on the obtained crude products of the pyridine derivatives, continuously supplementing water in the distillation process, carrying out distillation to obtain mixed liquid of the pyridine derivatives and water, and carrying out layering and separation to obtain high-purity prazole derivatives. The separation method has the advantages that the pyridine derivatives are separated and recovered by adopting the process, the operation is simple, the process is easy to control, the recovery rate of the pyridine derivatives is more than 97% and the product purity reaches 99.5%.

Description

technical field [0001] The invention belongs to the technical field of separation of chemical and chemical engineering, and in particular relates to a method for separating pyridine derivatives in the production of prazole. Background technique [0002] Meprazoles are proton pump inhibitors used to treat peptic ulcers. Because of the miraculous effect, the demand for omeprazole series drugs continues to expand, and the recovery of unconverted pyridine derivatives is becoming more and more important. [0003] Generally, prazoles are prepared by condensation of two important intermediates, the chloride containing pyridine ring and the corresponding derivative of benzimidazole. The synthesis process of pyridine ring-containing chlorides, important intermediates of prazoles, is prepared from pyridine derivatives through nitrogen oxidation, nitration (or chlorination), etherification, rearrangement, and chlorination. First, use hydrogen peroxide to oxidize pyridine derivatives ...

AI Technical Summary

Problems solved by technology

First use hydrogen peroxide to oxidize pyridine derivatives into nitrogen oxides of pyridine derivatives, and the conversion rate of pyridine derivatives in this reaction process is only about 90%, and there are still many raw materials that have not reacted, and the unreacted raw materials are brought to The following process not only affects the purification of the target product, directly affects the product yield, but also increases the load of environmental treatment

[0004] At present, rectification is commonly used to recover pyridine derivatives from waste liquid. However, due to the high boiling point of pyridine derivatives, traditional rectification methods are used for rectification. The internal temperature is high, the system components are complex, and the risk is high. Moreover, impurities are brought out during ordinary rectification, and there are many residues at the bottom of the rectification tank, and only a mixed solution containing about 50% of pyridine derivatives can be obtained. Further refining and purification are required, the process is complicated, and the product yield is low.

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