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A method for separating and purifying m-cresol from m-p-mixed cresol

A technology of mixing cresol and m-cresol, which is applied in the field of separation and purification of m-cresol, can solve the problems of high energy consumption, and achieve the effect of reducing energy consumption and solvent usage

Active Publication Date: 2014-10-22
BEIJING RISUN TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above documents and patents all use a single solvent as the crystallization solvent, and the crystallization temperature is below -10°C, which consumes a lot of energy

Method used

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  • A method for separating and purifying m-cresol from m-p-mixed cresol
  • A method for separating and purifying m-cresol from m-p-mixed cresol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Add raw material industrial m-cresol (purchased from Xingtai Xuyang Coal Chemical Co., Ltd.), m-cresol (57.9wt%), p-cresol (27.7wt%), 2,4‐xylenol in the reaction kettle (7.6wt%), 2,5-xylenol (4.9wt%), also contains part of o-cresol, phenol and 2-ethylphenol, when adding complexing agent urea, its addition is the same as that of raw material m-cresol The ratio is 0.6:1, the oil bath is heated to 80°C, and the temperature is maintained for 60 minutes. After the reaction is completed, cool down naturally to 60°C, slowly add petroleum ether with a boiling range of 60-90°C, the volume ratio of the amount of petroleum ether to the raw material p-cresol is 2:1, and after the addition is complete, put the reaction solution in cold water at 4°C Bath for crystallization, maintained for 2 hours; filtered, cooled to 4 ° C boiling range 60-90 ° C petroleum ether washing, the amount is 2 times the volume of mixed cresol between raw materials; filtrate rectification recovery petroleum...

Embodiment 2

[0022] The experimental device and operation are the same as in Example 1, except that the amount of petroleum ether used for washing crystals with a boiling range of 60-90° C. is 1 times the volume of p-cresol between raw materials. The results are shown in Table 1.

Embodiment 3

[0024] The experimental device and operation are the same as in Example 1, except that petroleum ether uses a boiling range of 90-120°C. The results are shown in Table 1.

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Abstract

The invention relates to a method for separating and purifying m-cresol from a mixture of m-cresol and p-cresol by using a complex crystallization method. The method comprises the following steps: 1) complex crystallization: adding a mixture of m-cresol and p-cresol into a reactor, adding urea and heating to 70-95 DEG C to completely dissolve the urea in the mixture of m-cresol and p-cresol; cooling, adding petroleum ether when the mixture is cooled 50-60 DEG C, wherein the adding amount of petroleum ether is 1-2 times the volume of the raw material of the mixture of m-cresol and p-cresol, and crystallizing at 0 DEG C-8 DEG C for 2-4 h; 2) solid-liquid separation washing to obtain white needlelike m-cresol complex crystals and a filtrate 1; 3) decomplexation: pumping the complex crystal and adding of toluene, decomplexing at 50-60 DEG C under the, and filtering while hot to obtain a solid urea and a filtrate 2, wherein the filtrate 2 is a mixture of m-cresol and toluene; and 4) distillation: separating m-cresol and toluene in the mixture filtrate 2 through vacuum distillation to obtain pure m-cresol and toluene.

Description

technical field [0001] The invention belongs to the field of separation and purification of chemical industry, and specifically relates to a method for separating and purifying m-cresol from m-p-mixed cresol by using a complex crystallization method. Background technique [0002] Cresol is an important fine chemical intermediate, and its three isomers (o-cresol, m-cresol and p-cresol) are all fine chemical products that are in short supply in China, especially m-cresol, which is seriously insufficient in domestic supply , needs to import about 6,000 tons per year to meet the domestic market demand. The main application fields of m-cresol are: synthesis of VE, preparation of pyrethroid pesticides, synthesis of spices, plastic antioxidants, etc. [0003] m-cresol and p-cresol are difficult to separate by ordinary distillation due to their very close boiling points. The separation methods of m-cresol and p-cresol can be divided into two categories: physical methods and chemic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/86C07C37/84C07C39/07
Inventor 杨雪岗张敏生彭永兴孙长江
Owner BEIJING RISUN TECH CO LTD
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