Method for recovering pyridine from aqueous solution

Abstract

The invention relates to a method for recovering pyridine from an aqueous solution. The method comprises the following steps: adjusting the pH value of a pyridine aqueous solution system to 1 by using hydrochloric acid; extracting pyridine by using cyclohexane and then adjusting the pH value to more than 12 by using sodium hydroxide; after an alkaline water layer is separated, carrying out reflux and water separation until there is no obvious water and then carrying out normal pressure rectification; and finally, carrying out distillation so as to obtain high-purity pyridine and recovering cyclohexane. The method provided by the invention has the advantages of simple operation, high efficiency, small environment stress and applicability to recovery of an aqueous pyridine solution with a concentration of 5 to 48%.

Description

technical field

[0001] The invention relates to the technical field of drug synthesis, in particular to a method for recovering pyridine from an aqueous solution. Background technique

[0002] Pyridine is a six-membered heterocyclic compound containing a nitrogen heteroatom. It can be regarded as a compound in which one (CH) in the benzene molecule is replaced by N, so it is also called nitrogen benzene. It is a colorless or slightly yellow liquid with a foul smell. It is a drug Organic bases, catalysts, solvents and raw materials commonly used in synthesis.

[0003] At present, pyridine is less produced domestically, and most of it depends on imports. If pyridine is recovered from waste liquid, it will not only alleviate the problem of insufficient supply of pyridine, but also reduce the harm of waste liquid to the environment and save costs. Since pyridine forms an azeotrope with water and has a high solubility in water, when the content of pyridine in water is low, it i...