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Method for improving diphenol recovery during phenol hydroxylation product separating and refining process

A technology of phenol hydroxylation and hydroquinone, which is applied in the field of improving the recovery rate of hydroquinone in the process of separation and purification of phenol hydroxylation products, can solve the problems of economic decline in the production process and affect the purity of hydroquinone products, and achieve The method is simple, the recovery rate is improved, and the cost is low

Active Publication Date: 2010-11-03
SHANGHAI HUAYI NEW MATERIAL
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AI Technical Summary

Problems solved by technology

This method can distill the hydroquinone in the tar as much as possible, but the disadvantage is that the third component is introduced in the rectification system, which may affect the product purity of hydroquinone; in addition, the third component in the tar discharge needs to be considered The loss of components, and the cost increase factors caused by the process of adding separation equipment to recover the third component
[0006] Hydroquinone is a high value-added chemical intermediate, and too much residue of hydroquinone products in tar will lead to a decline in the economics of the production process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Step 1: Put phenol, water, catalyst and hydrogen peroxide into a 50L reactor in sequence according to a certain proportion, and carry out phenol hydroxylation reaction. The specific composition of the reaction solution obtained after the reaction is: water content 37.5%, phenol content 53.5% , catechol content 5%, hydroquinone content 2.5%, tar content 2.5%. After the reaction, take multiple reaction solution samples on average.

[0020] Take a portion of the reaction solution, adopt batch distillation, dehydrate under normal pressure, and separate phenol, catechol, and hydroquinone under reduced pressure; in the final stage of separation, the pressure of the tower kettle is 4KPa, and different final temperatures of the tower kettle are given, and simultaneously observe Tar fluidity. At the end of the separation a tar is obtained. The detailed experimental conditions and data are listed in Table 1.

[0021] The obtained tar was weighed, pulverized, and dissolved in 1...

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PUM

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Abstract

The invention discloses a method of using physical means to improve the fluidity of tar and separate and recover diphenol. During production process of using phenol hydroxylation to prepare catechol / hydroquinone, certain amount of tar are byproducts, so more diphenol product needs to be reserved to improve the fluidity of the tar due to demanding to keep the conveyability of the tar in distillation separation system. The method is characterized in that: inherent composition with high fluidity is recovered from the tar and is re-added into phenol hydroxylation reaction products solution, thereby greatly improving the content of the composition with high fluidity in the tar and meeting the purpose of improving the fluidity of the tar. Because the fluidity of the tar is improved substantively, more diphenol product does not need to be reserved, thereby improving the recovery rate of the diphenol product. The method of using physical means to improve the fluidity of tar and separate andrecover diphenol has the advantages of no need to increase special equipment, simple operation process and obvious effect in lowering the content of the diphenol product in the tar and improving the recovery rate of the diphenol product.

Description

technical field [0001] The invention relates to a method for improving the recovery rate of hydroquinone in the separation and purification process of phenol hydroxylation to produce ortho / hydroquinone products. Background technique [0002] In the process of producing catechol and hydroquinone by phenol hydroxylation, while obtaining ortho / hydroquinone products, the generation of by-product tar is unavoidable. Tar is a mixture, mainly composed of hydroquinone, polyhydroxy diphenyl ether compounds and polyphenyl ether macromolecular compounds. In actual industrial production, due to the requirements of pipeline transmission, it is necessary to make the separated tar have a certain fluidity. The fluidity of tar is related to its composition. As the content of hydroquinone and polyhydroxydiphenyl ethers in tar decreases, its freezing point increases gradually, and finally loses fluidity and forms a coke-like solid. Therefore, in the process of separating the tar, in order to...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C39/08C07C37/68C07C37/74
Inventor 许宁赵志宏冯世强张春雷马建学邵敬铭
Owner SHANGHAI HUAYI NEW MATERIAL
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