Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method for preparing o-chlorotoluene through methylbenzene loop chlorination

A technology of o-chlorotoluene and ring chlorination, which is applied in chemical instruments and methods, preparation of halogenated hydrocarbons, catalytic reactions, etc., can solve the problem of reducing the total yield of p-chlorotoluene and o-chlorotoluene and insufficient selectivity of ortho-chlorination High, unfavorable industrial production and other issues, to achieve the effect of low cost, easy control, high selectivity

Active Publication Date: 2017-04-19
SOUTHEAST UNIV
View PDF3 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above method has the following disadvantages: the one is that the selectivity of ortho-chlorination is not high enough; the other is that the conversion rate of toluene is low, and the rectification method currently used for m-chlorotoluene is difficult to separate from p-chlorotoluene, and high-purity m-chlorotoluene must be obtained. Toluene, a large amount of chlorine must be introduced to convert m-chlorotoluene into dichlorotoluene with a higher boiling point, and also to convert part of p-chlorotoluene and ortho-chlorotoluene into dichlorotoluene to facilitate separation, thereby reducing the Total yield of chlorotoluene and o-chlorotoluene
[0004] At present, o-chlorotoluene is mainly prepared by using Lewis acid as a catalyst, chlorine gas as a chlorine source, and catalytic toluene selective chlorination (such as Chinese patent CN201510182680.8); according to the reported literature, in the toluene chlorination process, o-chlorotoluene The ratio to p-chlorotoluene is close to 2:1; in addition, traditional Lewis acids cannot be separated from chlorinated products, causing a large amount of waste water, polluting the environment, and not conducive to industrial production

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for preparing o-chlorotoluene through methylbenzene loop chlorination
  • Method for preparing o-chlorotoluene through methylbenzene loop chlorination
  • Method for preparing o-chlorotoluene through methylbenzene loop chlorination

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1. Auxiliary ionic liquid [BMTM]Cl-nZnCl 2 Preparation: Under nitrogen atmosphere, mix 0.2mol 1-methyl-3-butylimidazole chloride with 0.2molZnCl 2 Add it into a three-necked flask, stir to disperse evenly, and react at 120°C for 2 hours to obtain [BMTM]Cl-ZnCl 2 ;Change ZnCl 2 The amount of 0.4mol and 0.5mol respectively prepared [BMTM]Cl-2ZnCl 2 , [BMTM]Cl-2.5ZnCl 2 .

[0026] 2. Toluene chlorination reaction steps: Add 2.0mol toluene to a 500mL four-neck flask, add a certain amount of iron powder as a catalyst, and add a certain amount of [BMTM]Cl-nZnCl 2 Ionic liquid is used as auxiliary agent (n=2), stirs to make it disperse evenly; Pass into the chlorine gas after concentrated sulfuric acid drying with the speed of 50mL / min then in the system, react at a certain temperature for a certain hour to obtain o-chlorotoluene, tail gas After condensation, the unreacted chlorine gas is absorbed by NaOH solution; the reaction is carried out under the condition of avoidi...

Embodiment 2

[0029] Adopt the method of embodiment 1, difference is only: the [BMTM]Cl-nZnCl that described employing 2 In the ionic liquid auxiliary agent (n=1); The catalyzer described in the step 2 is ferric chloride, and the volumetric amount of the ionic liquid auxiliary agent is 1% of toluene, and the mass ratio of the catalyst and the auxiliary agent is 1:5, The temperature of the chlorination reaction is 30° C., the reaction time is 2 hours, and the purity of the final product can reach 93.3%.

Embodiment 3

[0031] Adopt the method of embodiment 1, useless point only is: the [BMTM]Cl-nZnCl that described employing 2 In the ionic liquid auxiliary agent (n=2.5); The ionic liquid auxiliary agent added in the step 2 is 5% of toluene by volume, the mass ratio of the catalyst and the auxiliary agent is 5:1, and the temperature of the chlorination reaction is 90 °C, the reaction time is 6 hours, and the purity of the final product can reach 95.7%.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a method for preparing o-chlorotoluene through methylbenzene loop chlorination. The method particularly includes the steps that iron powder or ferric trichloride is added into methylbenzene to serve as catalysts, [BMTM]Cl-nZnCl2 ionic liquid serves as an assistant (n is equal to 1, 2 or 2.5), and stirring is carried out; dry chlorine is led in, a suitable temperature is controlled under the dark condition to conduct chlorination, the o-chlorotoluene is obtained in a high-selectivity manner, and alkali liquor absorption is carried out after tail gas condensation to remove excessive unreacted chlorine; and after reacting is ended, a reacting product and the ionic liquid assistant are separated, the separated ionic liquid can be repeatedly used. Compared with the prior art, the method can well improve the methylbenzene conversion rate, and the o-chlorotoluene selectivity reaches 88%; in addition, the separated and recycled [BMTM]Cl-nZnCl2 ionic liquid is repeatedly used, the production cost is reduced, and the method is suitable for o-chlorotoluene industrial production.

Description

technical field [0001] The invention belongs to the technical field of compound preparation, and in particular relates to a method for preparing o-chlorotoluene by a toluene ring chlorination method. Background technique [0002] O-chlorotoluene is an important chemical raw material intermediate, widely used in pesticides, medicines, dyes, etc. [0003] When chlorine gas is used as the chlorine source for ring chlorination of toluene, Lewis acid FeCl is mostly used. 3 or iron powder as a catalyst for industrial production of o-chlorotoluene. The selectivity of this process is relatively poor, and p / o-chlorotoluene is only about 1:2 in the obtained chlorotoluene product. There are many invention patents on toluene chlorination mentioning that the addition of corresponding sulfur-containing additives can improve the para-selectivity, but so far there is no patent that can better improve the selectivity of o-chlorotoluene. The above method has the following disadvantages: th...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/12C07C25/02B01J31/30B01J23/745
CPCB01J23/745B01J31/30B01J2231/40C07C17/12C07C25/02
Inventor 胡慧书葛裕华
Owner SOUTHEAST UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com