Method for synthesizing cresol

Abstract

The invention discloses a method for synthesizing cresol. According to the method, chlorotoluene is produced through chlorination of methylbenzene, the reaction conversion rate is controlled at 95-98%; the produced mixed chlorotoluene comprising parachlorotoluene, o-chlorotoluene and m-chlorotoluene and liquid caustic soda the volume of which is three times that of the mixed chlorotoluene are hydrolyzed, the reaction conversion rate of the mixed chlorotoluene is controlled at 95-98%; the reaction product is cooled and then separated, neutralized and layered, extracted, distilled, rectified and tert-butylated so as to prepare o-cresol, m-cresol, and 2.6 butylated hydroxytoluene respectively; the mixed chlorotoluene does not need to be separated, so that the problems of high boiling treatment caused by rectification and manpower and material resource spent on rectifying and separating mixed raw materials in the existing production technology are thoroughly solved, pollutant emission is reduced, in addition, the yield of m-cresol with high additional value in the product synthesized by the method is improved to some extent, and the economic benefits are remarkable.

Description

technical field

[0001] The invention relates to the production field of fine chemical raw material intermediates, in particular to a method for synthesizing cresol. Background technique

[0002] The traditional cresol synthesis process all adopts single raw material production, does not adopt ortho-para-m-chlorotoluene as raw material production, and the prior art closest to this application is to adopt ortho-chlorotoluene hydrolysis to prepare o-cresol and m-cresol, Due to the direct production of p- and o-chlorotoluene on the toluene chlorination production line, m-chlorotoluene can not be separated from p-chlorotoluene, so only excessive chlorination is carried out to convert the meta-position into dichlorotoluene into dichlorotoluene The by-products that can be separated, when m-chlorotoluene is excessively chlorinated, a small amount of ortho-p-chlorotoluene is continuously chlorinated into dichlorotoluene, which increases the side reaction by as much as 5-7%, resulting...

Examples

Embodiment Construction

[0014] The invention provides a synthetic method of cresol, comprising producing chlorotoluene by chlorination of toluene, controlling the reaction conversion rate at 95-98% by chlorination of toluene, and producing a product composed of p-chlorotoluene, o-chlorotoluene and m-chlorotoluene The mixed chlorotoluene, the mixed chlorotoluene is hydrolyzed with 3 times the volume of liquid alkali, and the reaction conversion rate of the mixed chlorotoluene is controlled to be 95-98%. After the reaction product is cooled, it is separated, neutralized and layered, extracted, and distilled. , rectification, and tert-butylation make o-cresol, m-cresol and p-cresol respectively, and the specific process steps are as follows:

[0015] (1) High temperature and high pressure hydrolysis process

[0016] 1) Preparation before feeding: replace the material with water and enter the high-pressure reactor with a large flow rate through the high-pressure metering pump. When water flows out of the...

technical field

[0001] The invention relates to the production field of fine chemical raw material intermediates, in particular to a method for synthesizing cresol. Background technique

[0002] The traditional cresol synthesis process all adopts single raw material production, does not adopt ortho-para-m-chlorotoluene as raw material production, and the prior art closest to this application is to adopt ortho-chlorotoluene hydrolysis to prepare o-cresol and m-cresol, Due to the direct production of p- and o-chlorotoluene on the toluene chlorination production line, m-chlorotoluene can not be separated from p-chlorotoluene, so only excessive chlorination is carried out to convert the meta-position into dichlorotoluene into dichlorotoluene The by-products that can be separated, when m-chlorotoluene is excessively chlorinated, a small amount of ortho-p-chlorotoluene is continuously chlorinated into dichlorotoluene, which increases the side reaction by as much as 5-7%, resulting...

Examples

Embodiment Construction

[0014] The invention provides a synthetic method of cresol, comprising producing chlorotoluene by chlorination of toluene, controlling the reaction conversion rate at 95-98% by chlorination of toluene, and producing a product composed of p-chlorotoluene, o-chlorotoluene and m-chlorotoluene The mixed chlorotoluene, the mixed chlorotoluene is hydrolyzed with 3 times the volume of liquid alkali, and the reaction conversion rate of the mixed chlorotoluene is controlled to be 95-98%. After the reaction product is cooled, it is separated, neutralized and layered, extracted, and distilled. , rectification, and tert-butylation make o-cresol, m-cresol and p-cresol respectively, and the specific process steps are as follows:

[0015] (1) High temperature and high pressure hydrolysis process

[0016] 1) Preparation before feeding: replace the material with water and enter the high-pressure reactor with a large flow rate through the high-pressure metering pump. When water flows out of the...