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Method for preparing 4-methyl catechol

A technology of methyl catechol and p-cresol, which is applied in the preparation of 4-methyl catechol and the field of 4-methyl catechol, can solve the problems of low yield and pollution of the preparation method, Achieve the effects of high yield, easy access to raw materials, and high safety

Inactive Publication Date: 2014-09-10
SHANGHAI INST OF TECH
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0004] In view of the defects in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a kind of preparation method of 4-methylcatechol, the preparation of said 4-methylcatechol The method should solve the technical problems of serious pollution and low yield in the preparation method in the prior art

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  • Method for preparing 4-methyl catechol

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Experimental program
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Effect test

Embodiment l

[0026] 1) The 500ml three-necked flask is equipped with a stirrer, a thermometer, and a detachable reflux condensing device. Add 108g (1000mmol) p-cresol, then add 109g (1068mmol) acetic anhydride, heat with an adjustable pressure electric heating mantle, reflux reaction under stirring for 6.0 hours, change the reflux device to a vacuum distillation device, and steam the acetic acid and Excessive acetic anhydride, phenolic ester yield 98%.

[0027] p-cresol acetate, 1 HNMR (500MHz, CDCl3): δ(ppm)=7.21 (d, J = 8.2 Hz, 2H), 7.01 (d, J = 8.3 Hz, 2H), 2.38 (s, 3H), 2.32 (s, 3H).

[0028] 2) In a 500ml four-necked flask equipped with a stirrer, a thermometer, a detachable reflux condensing device, a constant pressure dropping funnel, passing through N2, tail gas absorption and other devices, add 120g (1066mmol) of pre-dewatered chlorobenzene, and stir Add 138g (1035mmol) of anhydrous aluminum trichloride, heat to 130~140°C, and drop in the product p-cresol acetate in 1). Continu...

Embodiment 2

[0033] 1) As described in Example 1, the ratio of p-cresol and acetic anhydride added is 1.0:3.0. The reaction was refluxed for 2.5 hours under stirring, and the yield was 99%.

[0034] 2) As described in Example 1, the inert solvent used was 150g of xylene, heated to 135~145°C, phenolic ester was added dropwise, and the reaction was stirred for 2.5h, wherein the molar ratio of phenolic ester to aluminum tribromide was 1.0:2.0, The molar ratio of phenolic ester to dilute acid is 1.0:2.5, the post-treatment temperature is 40℃, and the yield is 92%.

[0035]3) As described in Example 1, 2-hydroxy-5-methylacetophenone was dissolved in 15 times the mass of ethanol, and slowly dropped into a 20% potassium hydroxide solution at 15-20°C, wherein The molar ratio of sodium hydroxide to phenolic ketone is 1.5. Regulate the system by adding 15% hydrogen peroxide dropwise at -10 to -5°C, wherein the molar ratio of hydrogen peroxide to phenolic ketone is 2.0:1.0. Drop lye to maintain an...

Embodiment 3

[0037] 1) As described in Example 1, the ratio of p-cresol and acetyl chloride added is 1.00:1.01. The reaction was refluxed for 4.5 hours under stirring, and the yield was 92%.

[0038] 2) As described in Example 1, the inert solvent used is toluene 275g, heated to 110~120°C, phenol ester is added dropwise, stirred and reacted for 15 hours, wherein the molar ratio of phenol ester to aluminum chloride is 1:3, phenol ester The molar ratio with dilute acid is 1:5, the aftertreatment temperature is 20°C, and the yield is 86%.

[0039] 3) As described in Example 1, dissolve 2-hydroxy-5-methylacetophenone in 3 times the mass of dioxane, and slowly drop into a sodium carbonate solution with a mass fraction of 40% at 25~30°C , wherein the molar ratio of sodium hydroxide to phenolic ketone is 2.5. Regulate the system by adding 5% hydrogen peroxide dropwise at 0-5°C, wherein the molar ratio of hydrogen peroxide to phenolic ketone is 2.8:1.0. Drop lye to maintain an alkaline pH value...

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Abstract

The invention discloses a method for synthesizing 4-methyl catechol. The method comprises the steps of carrying out acylation reaction on p-cresol as a starting materia to obtain p-cresyl acetate, carrying out Fries rearrangement reaction in a high-boiling-point inert solvent to obtained 2-hydroxy-5-methyl acetophenone, alkalifying, forming a salt, oxidizing at a low temperature, after the reaction is completed, reducing the reaction solution, acidifying, extracting and concentrating to obtain a crude product and distilling the crude product to obtain the pure 4-methyl catechol. The method disclosed by the invention is environmental friendly, available in raw materials, mild reaction conditions, low requirements on equipment, simple operation, low production cost, less side effects and high yield and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a kind of 4-methylcatechol, specifically a kind of preparation method of 4-methylcatechol. Background technique [0002] 4-Methylcatechol is an organic compound with a wide range of uses, which can be used to prepare other pharmaceutical active compounds, as an intermediate, for the synthesis of antibacterial agents and antioxidants, and as a high-efficiency polymerization inhibitor for Photosensitive materials are used in sterilization and mildew prevention, and in the manufacture of apple-shaped spices, etc., which are used in the daily life industry and have broad application prospects. [0003] The synthesis and preparation of 4-methylcatechol has been extensively studied. It has been reported that one-step catalytic reaction using catalysts such as titanium silicon molecular sieves, but the highest yield is only 12%, most of the raw materials need to be recycled, and the cat...

Claims

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Application Information

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IPC IPC(8): C07C39/08C07C37/60
CPCC07C37/60C07C45/54C07C67/08C07C67/14
Inventor 毛海舫吴建新王朝阳王立志赵飞飞杨军艳
Owner SHANGHAI INST OF TECH
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