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...

Examples

Embodiment 1

[0016] The pharmaceutical waste liquid is filtered, and the pyridine aqueous solution containing 50% pyridine / 50% water is obtained from the pharmaceutical waste liquid by ordinary rectification for pretreatment.

[0017] Then mix the potassium fluoride solution with a concentration of 60% and the pretreated pharmaceutical waste liquid at a mass ratio of 2.0, and then introduce it into the stratifier and let it stand for 3 hours to stratify, and the water-enriched phase after stratification enters the evaporator Concentrated brine (potassium fluoride solution) with a concentration of 60% concentrated by steam at 140°C is returned to the stratifier for recycling, and the pyridine-rich phase from the stratifier enters the finished product tank and is used as a pyridine solvent in the pharmaceutical process.

Embodiment 2

[0018] Embodiment two: recovery effect

[0019] Use the method for reclaiming pyridine from pharmaceutical waste liquid according to the present invention, reclaim pyridine to pharmaceutical waste liquid containing 10% pyridine, first obtain pyridine containing 50% pyridine / 50% water from pharmaceutical waste liquid with ordinary rectification Aqueous solution, and then use 60% potassium fluoride concentrated solution and 50% pyridine / 50% water to recover according to different mass ratios. The recovery effect is shown in Table-1.

[0020] Table-1 Recovery effect

[0021]

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...

Examples

Embodiment 1

[0016] The pharmaceutical waste liquid is filtered, and the pyridine aqueous solution containing 50% pyridine / 50% water is obtained from the pharmaceutical waste liquid by ordinary rectification for pretreatment.

[0017] Then mix the potassium fluoride solution with a concentration of 60% and the pretreated pharmaceutical waste liquid at a mass ratio of 2.0, and then introduce it into the stratifier and let it stand for 3 hours to stratify, and the water-enriched phase after stratification enters the evaporator Concentrated brine (potassium fluoride solution) with a concentration of 60% concentrated by steam at 140°C is returned to the stratifier for recycling, and the pyridine-rich phase from the stratifier enters the finished product tank and is used as a pyridine solvent in the pharmaceutical process.

Embodiment 2

[0018] Embodiment two: recovery effect

[0019] Use the method for reclaiming pyridine from pharmaceutical waste liquid according to the present invention, reclaim pyridine to pharmaceutical waste liquid containing 10% pyridine, first obtain pyridine containing 50% pyridine / 50% water from pharmaceutical waste liquid with ordinary rectification Aqueous solution, and then use 60% potassium fluoride concentrated solution and 50% pyridine / 50% water to recover according to different mass ratios. The recovery effect is shown in Table-1.

[0020] Table-1 Recovery effect

[0021]

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