Preparation method of p-cymene

A technology for cymene and catalyst, applied in the field of deep processing of rosin, can solve the problems of expensive catalyst, product yield needs to be improved, catalyst preparation is complicated, etc., and achieves the effects of low price, wide use and improved selectivity

Active Publication Date: 2021-01-22
GUANGXI FORESTRY RES INST
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0009] As mentioned above, there are main problems in the existing technology of synthesizing p-cymene from turpentine oil: one is that the catalyst used for gas phase dehydrogenation to prepare p-cymene is very expensive, Dipentene with higher purity is needed; second, the product yield of the liquid phase method needs to be improved compared with the gas phase method, and the preparation of the catalyst is complicated; third, the direct isomerization dehydrogenation of pinene is used to prepare p-cymene, and the product contains more polymer

Method used

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  • Preparation method of p-cymene

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Embodiment 1

[0045] (1) turpentine (80%), catalyst and water are added in the reactor in a ratio of 100:7:25 by mass ratio, and the stirring is started at a stirring speed of 500 rpm. The controlled reaction temperature is 180° C., and the reaction time is 2 hours; The catalyst is alum;

[0046] (2) After the reaction is finished, the product is filtered to obtain a filtrate and a filter cake, and the filter cake is washed with ethanol to remove the residual product, and dried at 150° C. for reuse;

[0047] (3) adding the above-mentioned filtrate in the washing tank, adding water and washing for 2 times to obtain the crude product containing p-cymene;

[0048] (4) the above-mentioned crude product containing p-cymene is subjected to vacuum fractionation to obtain 3-pairs of Alkenes by-products and p-cymene products.

[0049] The fractionation described in step (4) is vacuum fractionation, and concrete operation is as follows:

[0050] S1: First discharge the air in the rectification to...

Embodiment 2

[0057] (1) turpentine (80%), catalyst and water are added in the reactor in a ratio of 100:5:25 by mass ratio, and stirring is started at a stirring speed of 400rpm. The controlled reaction temperature is 300°C and the reaction time is 2h; Said catalyst is 100 purpose aluminum powder;

[0058] (2) After the reaction is finished, the product is filtered to obtain a filtrate and a filter cake, and the filter cake is washed with ethanol to remove the residual product, and dried at 150° C. for reuse;

[0059] (3) The above-mentioned filtrate is added in the washing tank, and water is added to wash 3 times to obtain the crude product containing p-cymene;

[0060] (4) the above-mentioned crude product containing p-cymene is subjected to vacuum fractionation to obtain 3-pairs of Alkenes by-products and p-cymene products.

[0061] The fractionation described in step (4) is vacuum fractionation, and concrete operation is as follows:

[0062] S1: First discharge the air in the recti...

Embodiment 3

[0069](1) Add turpentine (80%), catalyst and water into the reactor in a mass ratio of 100:5:25, start stirring, stirring speed 500rpm, control the reaction temperature to 300°C, pressure 7-8MPa, react The time is 1-2h; the catalyst is 100 mesh zinc powder;

[0070] (2) After the reaction is finished, the product is filtered to obtain a filtrate and a filter cake, and the filter cake is washed with organic solvents such as ethanol, ethyl acetate, hexane to remove residual products, and dried at 200° C. for reuse;

[0071] (3) The above-mentioned filtrate is added in the washing tank, and water is added to wash 3 times to obtain the crude product containing p-cymene;

[0072] (4) the above-mentioned crude product containing p-cymene is subjected to vacuum fractionation to obtain 3-pairs of Alkenes by-products and p-cymene products.

[0073] The fractionation described in step (4) is vacuum fractionation, and concrete operation is as follows:

[0074] S1: First discharge the...

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Abstract

The invention discloses a preparation method of p-cymene, which relates to the technical field of deep processing of turpentine. The p-cymene is prepared by taking turpentine or a dipentene byproductgenerated by hydration and ethyl esterification reaction of turpentine as a raw material through heating reaction under the action of a catalyst. The catalyst comprises one or more of aluminum sulfate, potassium sulfate, alum, zinc powder, aluminum powder and zinc-aluminum alloy powder. The method can be suitable for preparing cymene through dehydrogenation of dipentene, can also be used for catalyzing direct isomerization dehydrogenation of pinene to generate p-cymene, is wide in raw material application range, and the GC content of a high-boiling-point polymer is smaller than or equal to 17%. The catalyst has the advantages of high selectivity, no corrosion, no toxicity, low price and mild reaction conditions.

Description

technical field [0001] The invention relates to the technical field of rosin deep processing, in particular to a preparation method of p-cymene. Background technique [0002] p-Cymene, p-Cymene, 1-Methyl-4-Cymene, are colorless and transparent oils with specific fragrance, boiling point 176-177°C, specific gravity 0.835-0.860, insoluble in water, easily Soluble in ethanol, ether, acetone and liquid paraffin. P-cymene exists in a variety of essential oils, and is the active ingredient of Rhododendron broadleaf, a plant in the Rhododendron family. It is a drug for expectorant, cough, and cough. [0003] P-cymene is also an important chemical product and an organic synthesis intermediate with a wide range of uses. It can be used in soft drinks, iced foods, candies, chewing gum, and seasonings; it can also be used to synthesize a variety of polycyclic musk fragrances (such as Umbrella musk, sandalwood musk, Tuna musk, etc.), drugs, herbicides, fungicides, etc. In addition, te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C5/367C07C7/00C07C7/04C07C15/02B01J27/055B01J21/02B01J23/06B01J21/18C07C67/04C07C67/54C07C69/14
CPCC07C5/367C07C7/005C07C7/04B01J27/055B01J21/02B01J23/06B01J21/18C07C67/04C07C67/54C07C15/02C07C69/14
Inventor 孟中磊周永红蒋剑春胡立红赵振东高守娜廖仲秋
Owner GUANGXI FORESTRY RES INST
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