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Separation and purification method of m-cresol

A purification method and m-cresol technology, which are applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of complex process, large solvent consumption, long production cycle, etc., and achieve high product purity, The effect of less solvent consumption and less solvent consumption

Active Publication Date: 2014-12-24
江苏富比亚化学品有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN102167658A In the m-cresol process of separation and purification by complex crystallization, n-hexane is used as solvent. After the reaction solution cools down, the solvent is then added dropwise. It is not a one-time feeding, and the crystallization temperature is low (-20~-10°C). The recovery of urea in the medium consumes a lot of energy, and the corresponding phenolic wastewater treatment is relatively difficult
[0007] In CN 103204766A and CN103333052A, cyclohexane or sherwood oil is used as the solvent in the complexation reaction and washing stage, and the obtained white needle-like complexed m-cresol-urea crystals are pyrolyzed by toluene at a high temperature, and the solvent consumption is large and energy-saving consumes a lot
[0008] The complexation crystallization process of the above-mentioned patents all involves the addition of solvents (non-one-time feeding) during the cooling process of the complexation stage, and the obtained complexes need to be washed and purified. The process is relatively complicated, the production cycle is long, and the amount of decomplexing solvent is large. Disadvantages such as high temperature and high energy consumption

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Using mixed cresol (p-cresol 16.5 wt.%, m-cresol 81.6 wt.%, 2,6-dimethylcresol 1.9 wt.%) as raw material, mixed cresol, urea, toluene and hexane were formed The mixed solvent is added in the reactor together, wherein the molar ratio of urea and mixed cresol-m-cresol is 0.7:1, and the add-on of the mixed solvent formed by toluene and hexane and the mass ratio of mixed cresol are 1:1, The volume ratio of toluene and hexane in the mixed solvent was 3:1. The reaction kettle was heated to 85 °C, kept for 2 h, then cooled to 50 °C, kept for 1 h, then crystallized at 7 °C for 1.5 hours, and filtered to obtain a white powder. Complex solid and filtrate A;

[0035] Filtrate A reclaims toluene and hexane through rectification under reduced pressure for the reuse of complexation reaction, and meanwhile, obtains a mother liquor rich in p-cresol, as the batching for the separation of p-cresol by oxalic acid method complexation;

[0036] The white powdery complex solid was added to ...

Embodiment 2

[0039] The experimental device and operation are the same as in Example 1, except that the composition of the raw material mixed cresol is: p-cresol 40wt.%, m-cresol 57wt.%, 2,6-dimethylcresol 3wt.%.

Embodiment 3

[0041] The experimental device and operation are the same as in Example 1, except that the raw material mixed cresol comes from self-produced mixed cresol (71.3wt.% p-cresol, 28.2wt.% m-cresol, 0.5wt.% 2,6-dimethylcresol ) through the oxalic acid complex crystallization method to separate the remaining mother liquor after p-cresol, the composition of mixed cresol in the mother liquor is: p-cresol 15.9wt.%, m-cresol 82.9wt.%, 2,6-dimethylformaldehyde Phenol 1.2wt.%.

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Abstract

The invention relates to a separation and purification method of m-cresol. The separation and purification method comprises the following steps: a) complexing: adding mixed cresol, urea and a mixed solvent formed by toluene and liquid alkane into a reactor, stirring, heating to increase the temperature to 65-90 DEG C, performing heat preservation for 1-2h, reducing the temperature to 40-60 DEG C, then cooling and crystallizing at the temperature of 0-20 DEG C for 1-2h, and filtering to obtain a complex solid and filtrate A; and b) decomplexing: adding the complex solid obtained in the step a) into an ether type solvent, stirring at the temperature of 10-60 DEG C, performing decomplexing reaction for 0.5-3h, and filtering to obtain urea and filtrate B; and performing decompression rectification on the filtrate B to obtain m-cresol. The method for separating m-cresol from mixed cresol is high in product purity, simple in process, low in solvent consumption, high in recovery rate and low in energy consumption and can operate at normal pressure, prevent the production of three wastes in a separation process and realize recycling of resources, so that the method is environment-friendly.

Description

technical field [0001] The invention belongs to the field of chemical separation and purification, and relates to a method for separating m-cresol from mixed cresols. Specifically, complex crystallization is used to separate mixed cresols to obtain high-purity m-cresol simply and efficiently. Background technique [0002] Cresol is an important chemical product, which includes three isomers: o-cresol, p-cresol, m-cresol, m-cresol is mainly used for the synthesis of vitamin E, spices, pyrethroid pesticides, anti- As an important intermediate of oxidant, with the increasing demand of downstream products, domestic m-cresol is often in a situation of short supply. Therefore, high-purity m-cresol products have broad market prospects. [0003] At present, the production of cresol mainly adopts the toluene sulfonation alkali fusion method, the cumyl toluene method, the phenol alkylation method, and the toluene chlorination hydrolysis method. These isomers exist at the same time i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/07C07C37/68C07C37/84
CPCC07C37/68C07C37/685C07C37/74C07C39/07
Inventor 屈良端杜成堂庄东青王亚光葛芳荪
Owner 江苏富比亚化学品有限公司
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