Method for preparing 2,3-dichloropyridine through Sandmeyer reaction catalyst

Abstract

The invention relates to a method for preparing 2,3-dichloropyridine through a Sandmeyer reaction catalyst. The method comprises the following steps: i, obtaining graphite oxide from natural graphiteand performing ultrasonic stripping, and performing molecular assembly on the graphite oxide and copper oxide so as to obtain a graphene-copper oxide composite catalyst; ii, adding 2-chloro-3-pyridinamine and concentrated hydrochloric acid into a first reactor, cooling to 5 DEG C below zero, slowly dropping an aqueous solution of sodium nitrite, and controlling the temperature to 5 DEG C below zero for later use; iii, adding hydrochloric acid and the composite catalyst into a second reactor, dropping the mixed solution in the first reactor under nitrogen protection, gradually raising the temperature to 40 DEG C after dropping, reacting for an hour, extracting with dichloromethane, and performing organic phase rotary evaporation, thereby obtaining the crude 2,3-dichloropyridine. According to the 2,3-dichloropyridine prepared by the method disclosed by the invention, the production cost can be reduced, the used graphene-copper oxide composite catalyst can be repeatedly utilized, and heavy metal pollution brought by copper in liquid waste can be reduced.

Description

technical field [0001] The invention relates to the technical field of preparation of pyridine derivatives, in particular to a method for preparing 2,3-dichloropyridine through a Sandmeyer reaction catalyst. Background technique [0002] 2,3-Dichloropyridine is a very important fine chemical intermediate, which is widely used in the synthesis of pesticides. For example, in the synthesis process of the new insecticide chlorantraniliprole, 2,3-dichloropyridine is the key intermediate. In 2007, DuPont's chlorantraniliprole insecticide went on the market and was widely recognized by the market. In 2008, the sales volume was 55 million US dollars, in 2011 it exceeded 600 million US dollars, and in 2014 it further increased to 1.2 billion US dollars. In addition, 2,3-dichloropyridine is widely used in the preparation of various medicines and pesticides, and can be used to synthesize antibiotics, drugs for treating cardiovascular and other diseases, agricultural insecticides, herb...

AI Technical Summary

Problems solved by technology

The advantage of the pyridine direct chlorination method is that the supply of raw material pyridine is abundant, but due to the final mixture with complex composition, it is not easy to separate, resulting in more impurities and low conversion rate

The advantage of the 2-chloropyridine method is that the starting material pyridine is rich in sources, but the disadvantage is that it is difficult to separate the target product and the yield is low

The starting material 3-chloropyridine in the 3-chloropyridine method has a relatively high price, and there is a problem that the product yield is not high

The 2,3,6-trichloropyridine reduction method has high requirements on operating conditions and reaction equipment, which brings great difficulty in safe operation

However, the current production of 1 ton of 2,3-dichloropyridine will produce 50 tons of wastewater containing heavy metal ions, which does not meet the requirements of green environmental protection.

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