WO2019019808A1

WO2019019808A1 - Method for synthesizing carvacrol by catalyzing dihydrocarvone isomerization

Info

Publication number: WO2019019808A1
Application number: PCT/CN2018/089942
Authority: WO
Inventors: 刘晓涛; 刘建国; 万猛
Original assignee: 淮安万邦香料工业有限公司
Priority date: 2017-07-28
Filing date: 2018-06-05
Publication date: 2019-01-31
Also published as: CN107365247A; CN107365247B

Abstract

The present invention discloses a method for synthesizing carvacrol by catalyzing dihydrocarvone isomerization, wherein Cu/Cr is used to catalyze the dehydroisomerization of dihydrocarvone so as to synthesize carvacrol; after the reaction is finished, the catalyst particles and the product are easy to separate, and same can be recycled many times and the catalytic efficiency thereof stays basically unchanged; and the reaction conversion rate is high, and none of the industrial three wastes are produced. In addition, the catalyst in the invention is cheap and easy to obtain, the process is simple, green and non-polluting, and same is more suitable for the industrial-scale production of carvacrol.

Description

Method for catalyzing isomerization of dihydrocarvone to carvacrol

Technical field

The invention belongs to the field of chemistry, and in particular relates to a method for chemical synthesis of carvacrol.

technical background

Carvacrol is a commonly used food additive and fragrance that has been approved as a safe food additive in the United States and Europe. It is a colorless to pale yellow thick oily liquid with the same odor as thymol, with low toxicity and natural characteristics.

Carvacrol has a very high application value, it inhibits bacteria, yeasts, fungi, insects and cockroaches by destroying and changing the cell membrane structure of the pathogenic bacteria, or the structure of the mycelium, or effectively inhibiting the activity of the conidia. It grows with good antibacterial and insecticidal effects. It is also an effective component of thyme's blood circulation and phlegm. It can realize platelets by mediating the signal transduction pathway of anti-thromboxin by G13 protein-linked RhoA/Rho-kinase. Activation is a natural antibacterial preservative that can be used in food, medicine, cosmetics and other fields. The current preparation methods and problems of carvacrol are as follows:

(1) A method for synthesizing carvacrol by reacting o-methylphenol with 2-chloropropane using o-methylphenol as a raw material and using aluminum trichloride or ferric chloride as a catalyst, which produces a large amount of aluminum salt and Iron salt solid waste, causing environmental pollution, limits its large-scale application in production.

(2) Using organic acid or inorganic acid as main catalyst, PEG-400 or PEG-600 as a cocatalyst to promote intramolecular rearrangement of carvone to form carvacrol, which will produce 5-isopropyl-2-methyl -2,4-cyclohexadienone, 5-isopropenyl-2-methyl-2,6-cyclohexadienol and other by-products, difficult to separate from carvone, complicated subsequent processing, increasing production costs And time, and the product yield is low.

(3) The copper is supported on activated carbon as a catalyst to dehydroisomerize carvone to carvacrol. The catalyst particles in this method are small and easy to adhere, but after the reaction, the catalyst is not easily separated from carvacrol. It is not conducive to the recovery of the catalyst, and the reaction conversion rate is low.

The invention provides a method for isomerization of dihydrocarvone to form carvacrol, and the active copper is supported on a chromium material to form a catalyst of the method, the process is simple, the green is pollution-free, the catalyst is easy to recycle, and is suitable for industrial scale. Production.

Summary of the invention

In order to achieve the above object, the technical solution adopted by the present invention is:

The dihydrocarvone undergoes a dehydroisomerization reaction under the action of the catalyst Cu/Cr. After the reaction is completed, the Cu/Cr is repeatedly removed by filtration, and the organic phase is subjected to vacuum distillation to obtain carvacrol. The reaction equation is as follows:

Preferably, the catalyst Cu/Cr is a catalyst formed by supporting active copper on a chromium material with a Cu/Cr molar ratio of 5:1.

The specific preparation steps in the technical solution of the present invention are as follows:

In the reaction vessel, dihydrocarvone and Cu/Cr catalyst were added separately, stirred uniformly, heated to 160-200 ° C, reacted for 4-5 h, cooled to room temperature, filtered to remove catalyst Cu/Cr for recycling, organic phase decompression Rectification to obtain carvacrol.

Preferably, the mass ratio of dihydrocarvone to active Cu is from 500 to 1000:2 to 50.

The invention adopts Cu/Cr to catalyze the dehydroisomerization of dihydrocarvone to synthesize carvacrol, the catalyst particles are slightly larger than the copper carbon catalyst, the adhesion of the reaction raw materials to the catalyst is high, and after the reaction, the catalyst particles and products are obtained. Easy to separate, can be recycled many times and the catalytic efficiency is basically unchanged, the reaction conversion rate is high, no industrial waste is produced; in addition, the catalyst in the invention is cheap and easy to obtain, the process is simple, the green is pollution-free, and is more suitable for industrial scale production. Carvacrol.

Detailed ways

The present invention will be further described in detail below by way of embodiments.

Example 1

500 g of dihydro carvone and 2.5 g of Cu/Cr catalyst (5:1 Cu/Cr molar ratio) were added to a 1000 mL reactor. After stirring, the temperature was raised to 160 ° C for 4 h. After GC showed that the reaction was completed, it was cooled to room temperature. The Cu/Cr catalyst was recovered by filtration, and the filtrate was subjected to vacuum distillation to obtain 345 g of carotenol having a purity of 99.2%, an effective yield of 69%, and 150 g of tetrahydrocarvone having a content of 99% was obtained in a yield of 30%.

Catalyst reuse: The Cu/Cr catalyst recovered by filtration was flushed to the reaction vessel with 500 g of dihydrocarvone, and the temperature was raised to 160 ° C for about 4 hours. After the GC showed that the reaction was completed, the Cu/Cr catalyst was continuously recovered by filtration, and the filtrate was decompressed. Rectification yielded 342 g of carvacrol with a content of 99.2%, an effective yield of 68.4%, and a yield of 99% of tetrahydrocarvone 156 g, a yield of 31.2%. By repeating this application 6 times, the catalyst efficiency was not significantly lowered.

Example 2

500 g of dihydro carvone and 3 g of Cu/Cr catalyst (5:1 Cu/Cr molar ratio) were added to a 1000 mL reactor. After stirring, the temperature was raised to 180 ° C for 4.5 h. After GC showed that the reaction was completed, it was cooled to room temperature. The Cu/Cr catalyst was recovered by filtration, and the filtrate was subjected to vacuum distillation to obtain 360 g of carotenol having a purity of 99.1%, an effective yield of 72%, and a 137 g of tetrahydrocarvone having a content of 99% was obtained in a yield of 27.4%.

Catalyst reuse: The Cu/Cr catalyst recovered by filtration was flushed to the reaction vessel with 500 g of dihydrocarvone, and heated to 180 ° C for about 4.5 h. After GC showed that the reaction was over, the Cu/Cr catalyst was recovered by filtration, and the filtrate was reduced. Press distillation was carried out to obtain 355 g of carvacrol having a content of 99.1%, an effective yield of 71.2%, and at the same time, 143 g of tetrahydrocarvone having a content of 99% was obtained in a yield of 28%. When the application was repeated 7 times, the catalyst efficiency was not significantly lowered.

Example 3

500 g of dihydro carvone and 5 g of Cu/Cr catalyst (5:1 Cu/Cr molar ratio) were added to a 1000 mL reactor. After stirring, the temperature was raised to 200 ° C for 5 h. After GC showed that the reaction was completed, it was cooled to room temperature and filtered. The Cu/Cr catalyst was recovered, and the filtrate was subjected to vacuum distillation to obtain 375 g of carotenol having a purity of 99.3%, an effective yield of 75%, and a yield of 99.1% of tetrahydrocarvone 123g, a yield of 24.6%.

Recycling of the catalyst: The Cu/Cr catalyst recovered by filtration was flushed to the reaction vessel with 500 g of dihydrocarvone, and the temperature was raised to 200 ° C for about 5 hours. After the GC showed that the reaction was completed, the Cu/Cr catalyst was continuously recovered by filtration, and the filtrate was decompressed. Rectification yielded 372 g of carvacrol with a content of 99.3%, an effective yield of 74.9%, and a yield of 99.1% of tetrahydrocarvone 125 g, a yield of 24.7%. By repeating this application 8 times, the catalyst efficiency was not significantly lowered.

Claims

A method for catalyzing the isomerization of dihydrocarvone to carvacrol, characterized in that: dihydrocarvone undergoes a dehydroisomerization reaction under the action of a catalyst Cu/Cr, and after the reaction is finished, the Cu is removed by filtration. /Cr is reused, and the organic phase is subjected to vacuum distillation to obtain carvacrol.
A method for synthesizing carvacrol by isomerization of dihydrocarvone according to claim 1, wherein the catalyst Cu/Cr is a catalyst formed by supporting active copper on a chromium material, Cu/Cr mole The ratio is 5:1.
A method for catalyzing the isomerization of dihydrocarvone to carvacrol according to claim 1 or 2, wherein the specific preparation steps are as follows:

In the reaction vessel, dihydrocarvone and Cu/Cr catalyst were added separately, stirred uniformly, heated to 160-200 ° C, reacted for 4-5 h, cooled to room temperature, filtered to remove catalyst Cu/Cr for recycling, organic phase decompression Rectification to obtain carvacrol.
A method for catalyzing the isomerization of dihydrocarvone to carvacrol according to claim 3, wherein the mass ratio of dihydrocarvone to active Cu is from 500 to 1000:2 to 50.