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Method for synthesizing p-cymene

A p-cymene and isopropenyl-based technology, which is applied in the field of synthesis of p-cymene, can solve the problems of environmental pollution, resource waste, etc.

Active Publication Date: 2022-05-24
南平青华科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the production of terpinene-4-ol mainly adopts terpinene as raw material, and is prepared through epoxidation reaction and isomerization hydrogenation. , to be incinerated. However, after analysis, the isomerized rectification still liquid is mainly p-mentha-1-ene-4,8-diol. If it is directly disposed of as waste, it will pollute the environment and cause waste of resources. If it can be used as a raw material The production of high value-added products not only reduces the pressure on environmental protection and improves the utilization rate of materials, but also creates greater economic benefits

Method used

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  • Method for synthesizing p-cymene
  • Method for synthesizing p-cymene
  • Method for synthesizing p-cymene

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preparation example Construction

[0077] Preparation of p-cymene

[0078] The present invention provides a kind of preparation of cymene, the method comprises the steps:

[0079]

[0080]

[0081] (1) adding the rectifying still liquid containing p-menthn-1-ene-4,8-diol to the acid aqueous solution, dehydration reaction takes place to obtain a 1-methyl-4-isopropenyl-1,4-ring The dehydration reaction solution of hexadiene;

[0082] (2) the dehydration reaction solution containing 1-methyl-4-isopropenyl-1,4-cyclohexadiene obtained in step (1) is left to stand for stratification, the lower layer is an aqueous methanesulfonic acid solution, and the upper layer is an organic Phase layer, the organic phase layer is washed with water to neutrality to obtain an organic phase washed with water to neutrality;

[0083] (3) washing the neutral organic phase obtained in step (2) into the hydrogenation reactor, replacing the air in the hydrogenation reactor with nitrogen, adding a catalyst, feeding hydrogen, and car...

Embodiment 1

[0092] The present embodiment 1 prepares p-cymene with the distillation still liquid containing p-menth-1-ene-4,8-diol as raw material

[0093] 1. The preparation of the distillation still liquid containing p-menthn-1-ene-4,8-diol:

[0094] The structure of terpinene-4,8-epoxide is as follows:

[0095]

[0096] 5000Kg isoterpinene-4,8-epoxide was reacted in 250Kg metatitanic acid at 150℃ for 8h. After the reaction, the reaction liquid was subjected to batch rectification under the condition of absolute pressure of 5KPa. The rectification was stopped after collecting the front impurities, the finished product of limonene-4-ol and the rear transition section to obtain a rectification still liquid containing p-menthn-1-ene-4,8-diol.

[0097] 2. Preparation of cymene:

[0098]

[0099] Step (1): add 100 g of methanesulfonic acid aqueous solution containing 1 wt% of methanesulfonic acid to 100 g of the distillation still liquid containing p-menthn-1-ene-4,8-diol, heat to 90...

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Abstract

The invention relates to a method for synthesizing p-cymene. Specifically, the invention provides the preparation method of the 1-methyl-4-isopropenyl-1, 4-cyclohexadiene, and the preparation method of the 1-methyl-4-isopropenyl-1, 4-cyclohexadiene is provided by the invention. The method is simple and convenient, and the obtained p-cymene is easy to separate, high in yield, free of 1, 8-cineole and high in purity.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a method for synthesizing p-cymene. Background technique [0002] At present, the industrial production process of cymene mainly adopts dipentene through catalytic dehydrogenation reaction. Dipentene undergoes hydrogenation and dehydrogenation at the same time in the process of dehydrogenation, and the selectivity to cymene is about 72%. At the same time, due to the presence of 1,8-cineole in the raw material of dipentene, it cannot be separated and removed from p-cymene by rectification, resulting in that the purity of p-cymene is difficult to meet the quality requirements. [0003] Terpinene-4-ol is currently extracted from natural plant essential oils, but it cannot be produced on a large scale due to insufficient raw material sources. Therefore, chemically synthesized terpinen-4-ol can be used as the main source for the production of terpinen-4-ol. At present, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C13/23C07C1/24C07C15/02C07C5/13C07C7/00C07C7/04
CPCC07C1/24C07C5/13C07C7/005C07C7/04C07C2601/16C07C13/23C07C15/02
Inventor 叶国梁江宇棋江承艳杨斌
Owner 南平青华科技有限公司