Method for preparing 8-hydroxyquinoline without solid wastes

Abstract

The invention discloses a method for preparing 8-hydroxyquinoline without solid wastes. The method includes: preparing acraldehyde from glycerin under the dehydration action of sulfuric acid, subjecting acraldehyde and ortho-aminophenol to exocondensation through reaction, subjecting to oxidative dehydration through o-nitrophenol to obtain a semi-finished product of 8-hydroxyquinoline, adopting sodium hydroxide for neutralizing sulfuric acid in the semi-finished product, subjecting to solid-liquid separation through a centrifugal machine to obtain a crude product of 8-hydroxyquinoline, and subjecting the crude product to distillation and slicing to obtain 8-hydroxyquinoline. The method is mild in reaction, an industrial production process is high in operability, easiness in reaction control, simplicity in subsequent treatment, low equipment investment and energy saving are realized, economic benefits are increased due to raw material recovery, and the 8-hydroxyquinoline yield reaches 85% or above.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a preparation method of 8-hydroxyquinoline. Background technique [0002] 8-Hydroxyquinoline is a white or light yellow crystal or crystalline powder, insoluble in water and ether, soluble in ethanol, acetone, chloroform, benzene or dilute acid, capable of sublimation, less corrosive, low toxicity, LD504800mg / kg. The traditional 8-hydroxyquinoline is prepared from o-aminophenol by ring closure. The traditional process for preparing 8-hydroxyquinoline is to add glycerin into an acid-resistant reaction pot, slowly add concentrated sulfuric acid under stirring, simultaneously add o-aminophenol and o-nitrophenol in sequence, then add fuming sulfuric acid, and heat up to 125°C, stop heating, naturally heat up to 140°C, keep warm for 4 hours, cool to below 100°C, pump into an acid-proof pot containing 10 times the amount of water (calculated as o-aminophenol), stir, and...

AI Technical Summary

Problems solved by technology

There are two disadvantages in this process: First, the traditional process is to add oleum at one time, whether it is to add oleum at low temperature first and then heat up, or to add oleum after heating up first, the amount of one-time addition is large, and the reaction of sulfuric acid is violent. , uneven, easy to produce a variety of by-products that will affect subsequent collection and utilization, and adding sulfuric acid at one time has high requirements for process operation and control, and the yield of 8-hydroxyquinoline is also low, only about 70%. Secondly, in the traditional process, the centrifuged mother liquor is concentrated through the concentration kettle, and the residue is treated as hazardous waste or concentrated through a three-effect evaporator, and the recycling industry is treated as hazardous waste, resulting in the glycerol in the residue cannot be recycled again, and the hazardous waste treatment process is cumbersome. cost too high