Preparation method of 2,6-dihydroxytoluene

A technology of dihydroxytoluene and diamino, which is applied in the field of preparation of 2,6-dihydroxytoluene, can solve problems such as inability to meet industrial production requirements, and achieve the effects of low cost, high product yield and high conversion efficiency

Inactive Publication Date: 2018-04-17
SUZHOU GAIDE FINE MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, studies have shown that there are many ways to synthesize 2,6-dihydroxytoluene. However, these synthesis methods have their own advantages and disadvantages, but they still cannot meet the requirements of industrial production.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A preparation method for 2,6-dihydroxytoluene, comprising the following steps:

[0024] (1) Dissolve 4-methylbenzoic acid in methanol, add diatomaceous earth and mix evenly, add a mixture of glacial acetic acid and dilute nitric acid, control the temperature at 40°C and stir for 3 hours, distill under reduced pressure, and cool to 10 °C, a solid was precipitated to obtain 3,5-dinitro-4-methylbenzoic acid;

[0025] (2) Dissolve the obtained 3,5-dinitro-4-methylbenzoic acid in ether, add FeCl 3 and MnO 2 , the temperature was raised to 60°C, hydrazine hydrate was added dropwise, refluxed for 4 hours, filtered after cooling, diethyl ether was distilled off, and the obtained solid was recrystallized to obtain 3,5-diamino-4-methylbenzoic acid;

[0026] (3) Dissolve the obtained 3,5-diamino-4-methylbenzoic acid in water, add dilute sulfuric acid and stir evenly, add ZnCl 2 , after stirring evenly, lower the temperature to -2°C, add sodium nitrite solution dropwise, and con...

Embodiment 2

[0032] A preparation method for 2,6-dihydroxytoluene, comprising the following steps:

[0033] (1) Dissolve 4-methylbenzoic acid in methanol, add diatomaceous earth and mix evenly, add a mixture of glacial acetic acid and dilute nitric acid, control the temperature at 60°C and stir for 5 hours, distill under reduced pressure, and cool to 10 °C, a solid was precipitated to obtain 3,5-dinitro-4-methylbenzoic acid;

[0034] (2) Dissolve the obtained 3,5-dinitro-4-methylbenzoic acid in ether, add FeCl 3 and MnO 2 , raised the temperature to 80°C, added hydrazine hydrate dropwise, refluxed for 6 hours, filtered after cooling, evaporated ether, and recrystallized the obtained solid to obtain 3,5-diamino-4-methylbenzoic acid;

[0035] (3) Dissolve the obtained 3,5-diamino-4-methylbenzoic acid in water, add dilute sulfuric acid and stir evenly, add ZnCl 2 , after stirring evenly, lower the temperature to 2°C, add sodium nitrite solution dropwise, continue stirring for 6 hours after...

Embodiment 3

[0041] A preparation method for 2,6-dihydroxytoluene, comprising the following steps:

[0042] (1) Dissolve 4-methylbenzoic acid in methanol, add diatomaceous earth and mix evenly, add a mixture of glacial acetic acid and dilute nitric acid, control the temperature at 40°C and stir for 5 hours, distill under reduced pressure, and cool to 10 °C, a solid was precipitated to obtain 3,5-dinitro-4-methylbenzoic acid;

[0043] (2) Dissolve the obtained 3,5-dinitro-4-methylbenzoic acid in ether, add FeCl 3 and MnO 2 , raised the temperature to 60°C, added hydrazine hydrate dropwise, refluxed for 6 hours, filtered after cooling, evaporated ether, and recrystallized the obtained solid to obtain 3,5-diamino-4-methylbenzoic acid;

[0044] (3) Dissolve the obtained 3,5-diamino-4-methylbenzoic acid in water, add dilute sulfuric acid and stir evenly, add ZnCl 2 , after stirring evenly, lower the temperature to -2°C, add sodium nitrite solution dropwise, and continue stirring for 6 hours ...

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PUM

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Abstract

The invention discloses a preparation method of 2,6-dihydroxytoluene. The preparation method comprises the following steps of dissolving prepared 3,5-diamino-4-methylbenzoic acid in water, adding dilute sulphuric acid, stirring uniformly, adding ZnCl2, reducing the temperature to minus -2 to 2 DEG C after stirring uniformly, dropwise adding a sodium nitrite solution into the mixture, continuouslystirring to react for 5-6 hours after the dropwise adding is finished, then adding water and dilute sulphuric acid, mixing uniformly, then heating for boiling, reacting for 30-45 minutes, then addingsodium hydroxide, carrying out reflux reaction for 1-2 hours, cooling to room temperature, adding diethyl ether, stirring for 20-40 minutes, then adding zeolite, stirring and mixing for 1-2 hours, carrying out reduced-pressure distillation after filtering, and preparing the 2,6-dihydroxytoluene. The preparation method disclosed by the invention has the beneficial effects that the raw-material costis low, the operation is simple, safe and reliable, the requirements for the environmental conditions are mild, the product purity is high and the yield is high.

Description

technical field [0001] The invention relates to the field of pharmaceutical intermediates, in particular to a preparation method of 2,6-dihydroxytoluene. Background technique [0002] Resorcinol is a dihydric phenol substituted with a hydroxyl group at the 1 and 3 positions of the benzene ring. It can be selectively introduced at the 2, 4, 5, and 6 positions of the benzene ring structure except for the position substituted by the hydroxyl group. Alkyl or aryl groups with different numbers of carbon atoms and structures make them have certain special physical and chemical properties and uses. [0003] 2,6-dihydroxytoluene, also known as 2-methylresorcinol, is one of the important chemical intermediates, used in synthetic resins, dyeing, medicine, pesticides, dyes, pigments, agricultural chemicals, explosives and photosensitive materials and other fields have been widely used. In the field of medicine, 1,3-dihydroxy-2-methylanthraquinone is prepared by cyclization with 2,6-d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/00C07C39/08C07C227/04C07C229/60C07C201/08C07C205/57
CPCC07C37/00C07C201/08C07C227/04C07C39/08C07C229/60C07C205/57
Inventor 李晓明
Owner SUZHOU GAIDE FINE MATERIALS CO LTD
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