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Preparation method for 2,6-dihydroxytoluene

A technology of dihydroxytoluene and tert-butyltoluene, which is applied in the field of preparation of 2,6-dihydroxytoluene, can solve the problems of low yield, high cost, and high product cost, and achieve good reaction selectivity, few by-products, The effect of high yield

Active Publication Date: 2015-05-13
ZHEJIANG DINGLONG TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above method (1) not only needs to be carried out under high temperature and high pressure conditions, but also has low yield and difficult separation of the resulting mixture, which is not suitable for industrial production; although method (2) can be industrially produced, methyl iodide is expensive and the product cost is high
[0007] Some of the above methods are too costly, and some are more difficult to operate in practice, all of which cannot meet the requirements of industrialized production.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A kind of preparation method of 2,6-dihydroxytoluene, comprises the steps:

[0027] (1) Nitration reaction: Put a certain amount of 148g p-tert-butyltoluene and 500g dichloroethane into a 1L four-necked bottle, stir, heat in a water bath to 40°C, and mix the prepared mixed acid (130g95% nitric acid and 280g98% sulfuric acid) Add dropwise to the dichloroethane solution of p-tert-butyltoluene, and the mixed acid will be added dropwise within 3 hours. After the dropwise addition, continue to stir and react for 3 hours. Sampling is detected until the reaction of p-tert-butyltoluene is complete, and the reaction solution is poured into 1kg of In the ice-water mixture, the reaction solution was layered, the organic layer was separated, and the aqueous phase was extracted with 400g dichloroethane, the layers were separated, the organic phases were combined, washed once with 200ml of 5% sodium hydroxide aqueous solution, and washed twice with water , water 200ml each time, reco...

Embodiment 2

[0031] A kind of preparation method of 2,6-dihydroxytoluene, comprises the steps:

[0032] (1) Nitration reaction: Put a certain amount of 148g p-tert-butyltoluene and 390g chloroform into a 1L four-necked bottle, stir, heat in a water bath to 50°C, and drop the prepared mixed acid (120g95% nitric acid and 130g98% sulfuric acid) Add it to the chloroform solution of p-tert-butyltoluene, drop the mixed acid within 2 hours, continue to stir and react for 3 hours after the addition is completed, take a sample to detect that the reaction of p-tert-butyltoluene is complete, and pour the reaction solution into 1kg of ice water In the mixture, the reaction solution was layered, and the organic layer was separated, and then the aqueous phase was extracted with 400g of chloroform, the layers were separated, the organic phases were combined, washed once with 200ml of 5% aqueous sodium hydroxide solution, and washed twice with water, each time Use 200ml of water to recover chloroform unde...

Embodiment 3

[0036] A kind of preparation method of 2,6-dihydroxytoluene, comprises the steps:

[0037] (1) Nitration reaction: Put a certain amount of 148g p-tert-butyltoluene and 600g toluene into a 1L four-necked bottle, stir, heat in a water bath to 35°C, add the prepared mixed acid (170g95% nitric acid and 400g98% sulfuric acid) dropwise to In the p-tert-butyltoluene solution, the mixed acid was added dropwise within 4 hours, and the dropwise addition was completed and the stirring reaction was continued for 5 hours. After sampling and detection, the reaction of the p-tert-butyltoluene was complete, and the reaction solution was poured into 1.2kg of ice-water mixture. Separate the layers, separate the organic layer, then extract the aqueous phase with 500g of toluene, separate the layers, combine the organic phases, wash once with 300ml of 5% aqueous sodium hydroxide solution, and wash twice with 300ml of water each time, recover toluene under reduced pressure , to obtain the crude pr...

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PUM

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Abstract

The invention relates to a preparation method for 2,6-dihydroxytoluene. The preparation method adopts p-tert-butyltoluene as a raw material which is subjected to nitration, reduction and hydrolytic tert-butyl elimination reactions to obtain 2,6-dihydroxytoluene. The preparation method has the characteristics of high selectivity and product purity, low cost, environmental friendliness and the like, and is a route with an industrialization prospect.

Description

technical field [0001] The invention relates to a preparation method of aromatic phenolic compounds, in particular to a preparation method of 2,6-dihydroxytoluene. Background technique [0002] 2,6-dihydroxytoluene, also known as 2-methyl resorcinol or 2-methylresorcinol, belongs to aromatic phenolic compounds and is an important chemical raw material, which can be widely used in pigments, dyes, and hair dyes , synthetic resin, medicine, pesticide and many other fields. [0003] There have been many studies on the preparation of 2,6-dihydroxytoluene. At present, the preparation methods of 2,6-dihydroxytoluene mainly include the following: (a) hydrolysis of 2,6-diaminotoluene; (b) by 1,3-cyclohexanedione as raw material, through CH 3 I or Mannich reaction introduces a methyl group at the 2-position and then dehydrogenates; (c) resorcinol is obtained by direct reaction with methanol or resorcinol is firstly introduced into tert-butyl at the 4,6-position, and then the 2-posit...

Claims

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Application Information

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IPC IPC(8): C07C39/08C07C37/05
CPCC07C37/05C07C201/08C07C209/36C07C39/08C07C205/06C07C211/50
Inventor 秦振伟潘志军肖庆军施云龙史元晓
Owner ZHEJIANG DINGLONG TECH
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