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

An ionic liquid, dichlorotoluene technology, applied in chemical instruments and methods, halogenated hydrocarbon preparation, organic chemistry and other directions, can solve the problems of difficult separation and purification of products, difficulty in selecting chlorination, low comprehensive yield, etc., and achieves good industrial performance. Application value, easy product separation, high conversion rate of raw materials

Inactive Publication Date: 2015-07-29
NANJING ZHONGTENG CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many steps in this reaction, and the diazotization reaction causes many wastes, the reaction is dangerous and the comprehensive yield is low
[0006]2) Direct chlorination of toluene, 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

Method used

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  • Method for preparing 2,6-dichlorotoluene by catalyzing o-chlorotoluene with ionic liquid
  • Method for preparing 2,6-dichlorotoluene by catalyzing o-chlorotoluene with ionic liquid
  • Method for preparing 2,6-dichlorotoluene by catalyzing o-chlorotoluene with ionic liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1: A preparation of 2,6 by selective chlorination of o-chlorotoluene – The method of dichlorotoluene comprises the following steps:

[0025] 1) Ionic liquid [BMIM]Cl-2AlCl 3 Preparation of N 2 Under protection, 0.65 mol of 1 – Methylimidazole and 0.7 mol of chlorobutane were stirred and mixed in a 250 mL three-necked flask with a condenser, and the temperature was raised to 80 °C for 48 h under reflux. The product was separated by a separatory funnel, the unreacted liquid was removed, and then washed 3 times with 20 mL of ethyl acetate. The crude product was evaporated under vacuum at 60 °C to remove residual ethyl acetate, and dried in vacuum at 70 °C for 24 h. The obtained light yellow liquid was [BMIM]Cl ionic liquid intermediate, which was stored in dry N 2 Reserve under atmosphere.

[0026] 2) N 2 In the atmosphere, at 120 °C, 34.92 g (0.2 mol) of the intermediate prepared above and 53.6 g (0.2 mol) of anhydrous AlCl 3 Add to a three-necked flask, s...

Embodiment 2

[0035] Example 2: A preparation of 2,6 by selective chlorination of o-chlorotoluene – The method of dichlorotoluene comprises the following steps:

[0036] Adopt the same method of implementation 1 to prepare chloroaluminate ionic liquid, and the chlorination reaction process of o-chlorotoluene adopts the same method of implementation 1, but change [BMIM]Cl-2AlCl 3 The amount of ionic liquid is 0.05 g, 0.15 g, 0.5 g, to explore [BMIM]Cl-2AlCl 3 The impact of the consumption of ionic liquid on o-chlorotoluene chlorination process, as table 2:

[0037] Table 2 [BMIM]Cl-2AlCl 3 Effect of the dosage of ionic liquid on the chlorination of o-chlorotoluene

[0038]

[0039] It can be seen from Table 2 that with the increase of the amount of catalyst, the reaction rate of o-chlorotoluene is gradually accelerated, and the selectivity of 2,6-dichlorotoluene increases first and then decreases. Among them, when the catalyst dosage is 0.5%, the selectivity of 2,6-dichlorotolue...

Embodiment 3

[0040] Example 3: A preparation of 2,6 by selective chlorination of o-chlorotoluene – The method of dichlorotoluene comprises the following steps:

[0041] Adopt the same method of implementation 1 to prepare chloroaluminate ionic liquid, the chlorination reaction process of o-chlorotoluene adopts the same method of implementation 1, but change the reaction temperature to 50 ℃ and 70 ℃, and explore the chlorination process of o-chlorotoluene at different reaction temperatures The impact, as shown in Table 3:

[0042] Table 3 Effect of different reaction temperatures on the chlorination of o-chlorotoluene

[0043]

[0044] It can be seen from Table 3 that as the reaction temperature increases, the reaction rate increases, while the selectivity of the by-product trichlorotoluene gradually increases, which in turn leads to a gradual decrease in the selectivity of 2,6-dichlorotoluene. Among them, when the reaction temperature is 30℃, the selectivity of 2,6-dichlorotolue...

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Abstract

The invention discloses a method for preparing 2,6-dichlorotoluene by catalyzing o-chlorotoluene with an ionic liquid. According to the method for preparing 2,6-dichlorotoluene, Cl2 is taken as a chlorinating agent, under the action of a catalyst, namely, an aluminium chlorate ionic liquid, a raw material, namely, o-chlorotoluene, is directionally chlorinated, and the 2,6-dichlorotoluene is prepared; an intermediate of the aluminium chlorate ionic liquid is [BMIM]Cl, the molar ratio of AlCl3 to [BMIM]Cl is 1:3, and the usage amount of the aluminium chlorate ionic liquid accounts for 0.1%-1% of the mass of o-chlorotoluene; the method for preparing 2,6-dichlorotoluene by selectively chlorinating the o-chlorotoluene is simple in technology and mild in reaction condition, the used aluminium chlorate ionic liquid is good in catalytic activity and good in stability, can be separated from a product easily and can significantly improve the selectivity of 2,6-dichlorotoluene, and the method has the very 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, dicloxacillin for medicine and wool fabric dyeing Dye acid medium bleaching blue B; 2,6-dichlorotoluene can be used to produce herbicide 2,6-dichlorobenzonitrile through ammonia oxidation, which can be further processed into pesticide herbicide Cao Kele, fluorine-containing acyl urea insecticides, etc. , 2,6-dichlorotoluene can also produce 2,4-dichloro-3-methylphenol, 2,4-dichloro-3-methylacetophen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C25/02C07C17/12
Inventor 钟华陆敏山陈秀珍刘巧宝
Owner NANJING ZHONGTENG CHEM
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