A method for preparing 2,6-dichlorotoluene by catalyzing o-chlorotoluene with ionic liquid

Abstract

The invention discloses a method for preparing 2,6-dichlorotoluene by catalyzing o-chlorotoluene with an ionic liquid. The method for preparing 2,6-dichlorotoluene uses Cl2 as a chlorination agent, and the catalyst is chloroaluminate ionic liquid Under the action of the raw material, the directional chlorination of o-chlorotoluene makes 2,6-dichlorotoluene; the intermediate of the aluminum chlorate ionic liquid is [BMIM]Cl, wherein the molar ratio of AlCl3 to [BMIM]Cl is 1 ~3, the dosage of the chloroaluminate ionic liquid is 0.1%~1% of the mass of o-chlorotoluene; the selective chlorination of o-chlorotoluene to produce 2,6-dichlorotoluene is simple in process and mild in reaction conditions. The chloroaluminate ionic liquid has good catalytic activity, good stability, is easy to separate from the product, and can significantly improve the selectivity of 2,6-dichlorotoluene. The invention has high industrial application value.

Description

technical field [0001] The invention relates to the application field of ionic liquid catalysts, in particular to a method for preparing 2,6-dichlorotoluene by using ionic liquid to catalyze o-chlorotoluene. Background technique [0002] 2,6-Dichlorotoluene is an important fine chemical raw material for the manufacture of fungicides, insecticides, herbicides, dyes and pigments, pharmaceuticals and other chemical products. 2,6-dichlorotoluene can produce 2,6-dichlorobenzaldehyde, which can be further processed to produce pharmaceutical intermediate 2,6-dichlorobenzaldehyde oxime, diclofenac for medical use and dyeing of wool fabrics. Dyestuff Acidic Medium Bleach Blue B; 2,6-dichlorotoluene can be processed into herbicide 2,6-dichlorobenzonitrile by ammonia oxidation, which can be further processed into pesticide herbicide Cao Keluo, fluorine-containing acyl urea insecticide, etc. , 2,6-dichlorotoluene can also produce 2,4-dichloro-3-methylphenol, 2,4-dichloro-3-methylacetop...

AI Technical Summary

Problems solved by technology

[0003] 2,6-dichlorotoluene has a wide range of uses and has attracted more and more attention. At present, there is no domestic scale production and it mainly relies on imports, which seriously restricts the development and research of downstream products.

There are many steps in this reaction, and the diazotization reaction causes many wastes, the reaction is dangerous and the comprehensive yield is low

2) Toluene is directly chlorinated, and the yield and chlorination selectivity of this method are very low, and the separation and purification of the product is difficult

This method has a large amount of waste acid waste water and poor economy

4) Alkyltoluene chlorination method, which basically introduces a tert-butyl positioning group. In this synthesis, chlorination is easy to generate 4-tert-butyl-2,5-dichlorotoluene, and the selected chlorine at the 2-position and 6-position generation is very difficult