Preparation method for p-isoproplyl toluene

A technology for p-Cumene and p-Mentane, which is applied in the field of preparation of p-Cumene, can solve the problems of high production cost, high equipment corrosiveness, expensive catalyst and the like, and achieves the effects of low production cost and simple operation.

Inactive Publication Date: 2008-07-09
TAICANG YONGJIA PHARMA
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  • Description
  • Claims
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Problems solved by technology

There are many reports about the synthesis of dipentene to cymene, such as utilizing the gas-phase dehydrogenation of heavy metal catalysts, although satisfactory results can be obtained, but the catalyst is more expensive, and the requirements for reaction equipment are higher (gasification bed is required), and the production High cost; Chines...

Method used

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Embodiment Construction

[0012] The specific embodiment of the present invention is described below:

[0013] According to the preparation method of the p-cymene of present embodiment, comprises the steps:

[0014] (1) In the reactor of 1000L, add 11.9kg containing palladium and be the palladium charcoal of 5% (weight content) and the dipentene extracted from turpentine oil of 80kg, start to drop the dipentene after gradually warming up to 168 ℃-170 ℃ Pentene 500kg, time of dropping is 2 hours, obtains the mixture containing p-cymene and p-menthane after being incubated at this temperature for 1 hour.

[0015] (2) the mixture obtained through step (1) is extracted with a vacuum and enters a height of 18m, the number of trays is 140, and a diameter is carried out in a fractionating tower of 0.7m to carry out a fractionation operation. One) fractional distillation is removed, obtains the crude product of p-cymene.

[0016] (3) Add 5% aqueous sodium hydroxide solution to the crude product of p-isopropy...

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Abstract

The invention relates to a process for preparing p-Cymene, which takes dipentene as raw material and palladium carbon as catalyst to react at a temperature of 160DEG C-180DEG C for 1-12 hours to obtain mixture of p-Cymene and p-menthane, then the p-menthane is removed via fractional distillation to obtain crude products of p-Cymene, and lastly water containing soda is added in the crude products of p-Cymene which are then heated to 170DEG C-190DEG C and after heat preservation for 5-30 minutes charged in a fractionating tower for fractionating operation to obtain products of p-Cymene. The content of p-Cymene obtained through the preparing process of the invention reaches above 99% with low production cost.

Description

technical field [0001] The invention relates to a preparation method of p-cymene. Background technique [0002] p-Cymene is p-cymene, which is not only the raw material for the synthesis of precious fragrances such as sandalwood musk and tuna musk, but also the raw material for the synthesis of important chemical products p-cresol. my country is rich in turpentine resources, and a large amount of by-product dipentene is produced in the production process of synthesizing camphor and terpineol with turpentine as raw materials. At present, the camphor and terpineol manufacturers in my country produce thousands of tons of dipentene every year, which are mainly used as solvents with low prices. Using catalytic hydrogenation to convert dipentene into p-cymene can greatly improve its use value and economic benefits. There are many reports about the synthesis of dipentene to cymene, such as utilizing the gas-phase dehydrogenation of heavy metal catalysts, although satisfactory res...

Claims

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Application Information

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IPC IPC(8): C07C15/02C07C5/31C07C7/04
Inventor 钟惠明
Owner TAICANG YONGJIA PHARMA
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