Method for recycling pyridine from pharmaceutical waste liquid

Abstract

The invention relates to a method for recycling pyridine from a pharmaceutical waste liquid and belongs to the field of recycling method of wastes. The method for recycling pyridine from the pharmaceutical waste liquid comprises following steps: (1) filtering and pre-treating the pharmaceutical waste liquid; (2) mixing a potassium fluoride solution having a certain concentration with the pre-treated pharmaceutical waste liquid according to a certain mass proportion to obtain a mixture; (3) feeding the mixture to a layering device and allowing the mixture to stand for three hours for layering; (4) feeding a water-enriched phase after layering to an evaporator with steam at 140 DEG C being fed; and (5) recycling concentrated strong salt water back to the layering device for recycling. In the method recycling pyridine from a pharmaceutical waste liquid, the pyridine can be recycled from the pharmaceutical waste liquid through common rectification and a salt-adding phase-separating method are employed. When a mass ratio of the potassium fluoride solution being 60% in concentration and a material composed of 50% of the pyridine and 50% of water is 2.0, purity of the pyridine in an organic phase can reach 92.60%. A separation performance of a potassium fluoride weak solution in the water phase is not influenced after being recycled through the evaporator. The method is simple in process, is convenient to operate and is low in cost.

Description

technical field [0001] The invention relates to a method for recovering pyridine from pharmaceutical waste liquid, belonging to the field of waste recycling methods. Background technique [0002] In recent years, a new type of pesticide, thiodicarb, has been successfully developed at home and abroad. Due to its good insecticidal effect and low pesticide residue, it has been paid more and more attention. However, pyridine must be used as a solvent in the synthesis process of this pesticide to produce qualified thiodicarb products, so pyridine waste water will inevitably be produced in the production process. Pharmaceutical companies use pyridine as a solvent, and about 8m3 of waste water containing 10% (mass fraction) of pyridine is produced every day during the production process. Since the recovery of pyridine in wastewater has not been solved, nearly ten million yuan of pyridine is wasted every year, and high sewage charges must be paid at the same time. Since pyridine a...

AI Technical Summary

Problems solved by technology

Since the recovery of pyridine in wastewater has not been solved, nearly ten million yuan of pyridine is wasted every year, and high sewage charges are also required.

Since pyridine and water form an azeotrope system, its azeotropic composition is pyridine:water=57.0:43.0 (mass fraction), which brings great difficulties to the separation of pyridine-water system

The existing domestic sodium hydroxide method to treat pyridine wastewater produces secondary pollution

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