Preparation method for increasing yield of 2,3-dichloropyridine

Abstract

The invention discloses a preparation method for increasing the yield of 2,3-dichloropyridine, and relates to the technical field of 2,3-dichloropyridine preparation, wherein the preparation method comprises the following steps: S1, adding 2,3,6-trichloropyridine, a NiO / nano ceramic catalyst, a buffer agent and an acid-binding agent into ethanol, stirring, heating, carrying out inert gas replacement, introducing hydrogen to maintain the pressure, and carrying out a reaction to prepare a reaction solution; S2, filtering the reaction solution to prepare a NiO / nano ceramic catalyst and an original solution; S3, carrying out dry distillation on the original solution to prepare ethanol and a dry-distilled solution; S4, adding water into the dry-distilled solution, carrying out phase separation, and thus obtaining a mixed molten organic matter solution of 2,3,6-trichloropyridine and 2,3-dichloropyridine; S5, dropwise adding the mixed molten organic matter solution of 2,3,6-trichloropyridine and 2,3-dichloropyridine into hydrochloric acid, stirring, and carrying out filter pressing to obtain unreacted 2,3,6-trichloropyridine and an intermediate solution; and S6, adding water into the intermediate solution to separate out 2,3-dichloropyridine, and filtering.

Description

technical field [0001] The invention relates to the technical field of preparation of 2,3-dichloropyridine, in particular to a preparation method for increasing the yield of 2,3-dichloropyridine. Background technique [0002] 2,3-Dichloropyridine is a key intermediate in the synthesis of chlorantraniliprole. The existing preparation process often prepares 2,3-dichloropyridine by catalytic hydrogenation and dechlorination of 2,3,6-trichloropyridine. The catalysts often used include palladium / carbon catalysts, etc. The acid-binding agent often uses NaOH. The catalyst and the acid-binding agent are not only expensive, but also the reaction product of the acid-binding agent wraps the catalyst, resulting in the problems of low catalyst activity and low reaction selection. Contents of the invention [0003] Aiming at the defects in the prior art, the invention provides a preparation method for increasing the yield of 2,3-dichloropyridine. [0004] The preparation method, the s...

AI Technical Summary

Problems solved by technology

The existing preparation process often prepares 2,3-dichloropyridine by catalytic hydrogenation and dechlorination of 2,3,6-trichloropyridine. The catalysts often used include palladium / carbon catalysts, etc. The acid-binding agent often uses NaOH. Catalysts and acid-binding agents are not only expensive, but also the reaction product of the acid-binding agent wraps the catalyst, resulting in low catalyst activity and low reaction selection.