JPS5821893B2 - phenol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing phenols by decomposing aromatic hydroperoxides.

More specifically, the present invention relates to a method for producing phenols by decomposing a secondary or tertiary alkyl aromatic hydroperoxide in the presence of a catalyst.

Conventionally, phenols have been produced on a large scale by decomposing tertiary alkyl hydroperoxides, particularly cumene hydroperoxides, in the presence of acid catalysts such as sulfuric acid or perchloric acid.

In this production method, the yield based on hydroperoxide is reported to be about 90% for phenol and about 80% for ketone, but it is still unsatisfactory industrially in the following points.

That is, firstly, the yield of phenol obtained is low, and at the same time, a considerable amount of polymeric resinous substances are produced as by-products, making the phenol separation process complicated.

Second, plants using acid catalysts usually require expensive corrosion-resistant equipment.

Third, the acid catalyst must be removed or neutralized before separating the phenol from the decomposition products.

Furthermore, from an industrial perspective, the production method of cumene, in which phenol and ketones are co-produced, is not necessarily perfect, and a cheaper, higher-yield catalyst can produce high yields of useful products other than ketones. It is desirable to realize a manufacturing method that allows simultaneous production of

In order to efficiently produce phenols by decomposing alkyl aromatic hydroperoxides, the present inventors intended a highly economical phenol synthesis method, especially by decomposing tertiary alkyl aromatic hydroperoxides, and Efforts were made to develop a new catalyst to replace the existing catalyst.

As a result, the present invention was completed.

The characteristics of the present invention are that secondary and tertiary alkyl aromatic hydroperoxides are used as raw materials, and that the decomposition is carried out in the presence of phosphorus sulfide as a catalyst.

The nature of the aldehyde or ketone produced at the same time is determined by the structure of the hydroperoxide, and generally, aldehydes and ketones are produced from tertiary alkyl aromatic hydroperoxide and tertiary alkyl hydroperoxide, respectively.

Based on the method of the present invention (when using a catalyst), there are various economic effects.

The most surprising feature of the process of the invention is that the yield of phenol using tertiary alkyl aromatic hydroperoxides is significantly higher than with acid catalysts.

For example, according to the method of the present invention, the yield of phenol obtained from engineered methylbenzene hydroperoxide is 90%.
Exceed.

Moreover, as a result of the high yield of phenol, the amount of polymeric resinous substances produced as by-products when decomposing alkyl aromatic hydroperoxides is significantly reduced compared to conventional acid-catalyzed methods.

Furthermore, since a strong acid is not used as a catalyst, a reactor made of a special corrosion-resistant material is not required for hydroperoxide decomposition.

Moreover, the complicated process for neutralizing the acid catalyst prior to the separation process of phenols can be significantly simplified.

The phosphorus sulfide used as the catalyst used in the method of the present invention may be a binary compound consisting of sulfur and phosphorus, and can be used regardless of its composition ratio.

Specific examples include niphosphorus pentasulfide (P2S5), tetraphosphorus heptasulfide (P4 S7 ), tetraphosphorus pentasulfide (P4S5), and tetraphosphorus trisulfide (P4S3).

Even if the catalyst is added alone to the reaction system, benzene, toluene,
It may be added after being dissolved in a suitable organic solvent such as ethylbenzene or xylene.

Only a small amount of catalyst may be used in the process of the present invention, and
Up to 20% by weight, based on the oxide, is sufficient.

In a preferred embodiment of the invention, an amount of 0.01 to 10% by weight of hydrocarbon oxide is used.

Aromatic hydrocarbons used as raw materials in the method of the present invention
The oxide is a secondary or tertiary alkyl aromatic hydroperoxide containing an alkyl chain.

The alkyl chain preferably has 2 to 24 carbon atoms, particularly 2 to 12 carbon atoms.

Among these, the ones with the highest industrial applicability are ethylbenzene hydroperoxide and cumene hydroperoxide.

It is also possible to use substituents of secondary or tertiary alkyl aromatic hydroperoxides, such as those containing on the aromatic nucleus one or more substituents selected from rogen atoms, alkyl, alkoxy and nitro.

Decomposition of such substituted products yields the corresponding phenol substituted products.

or di(tertiary alkyl) or di(tertiary alkyl)
Aromatic dihydrolovaoxide, ie, an aromatic nucleus substituted with two secondary or tertiary alkylnohydrolovaoxide atomic groups, can be used.

In this case, dihydro-type phenol is obtained by decomposition.

One or more substituents may be present on such cybidrobar oxides, in which case the corresponding dihydro-type phenol substituent is obtained.

The preferred reaction temperature range for carrying out the method of the present invention is from room temperature to 200°C, preferably from 80°C to 180°C, more preferably from 120°C to 160°C.

Although the reaction pressure varies depending on the equipment type and operating conditions, it is generally preferable to carry out the reaction in the range of normal pressure to 10 kg/ffl; In order to avoid reaction, it is also possible to carry out the decomposition under reduced pressure and to operate while removing aldehydes or ketones from the reaction system.

Although the reaction time varies depending on conditions such as reaction temperature and catalyst concentration, it is usually 1 minute to 1 hour, and in a preferred reaction temperature range of 120 DEG C. to 160 DEG C., 1 minute to 15 minutes is sufficient.

In carrying out the process of this invention, it is common to carry out the decomposition reaction in an inert solvent, ie a solvent that does not react with the hydroperoxide and the decomposition products.

Examples of inert solvents include benzene, toluene, ethylbenzene, xylene, ethylmethylbenzene, diethylbenzene, p-cymene, diisoglopylbenzene, chlorbenzene and nitrobenzene.

The decomposition of aromatic hydrocarbon oxide in the method of the present invention can be carried out either batchwise or continuously, and is not limited to any particular format.

Aromatic hydrocarbons used as raw materials in the method of the present invention
The oxide can be synthesized by conventional methods, such as automatic oxidation of an alkyl aromatic compound.

The aromatic hydrocarbon oxide obtained by such a method does not necessarily have to be strictly pure;
A mixture containing crude products obtained from the partial oxidation of an alkyl aromatic compound can also be subjected to a decomposition reaction.

The alkyl aromatic compound that serves as a raw material for automatic oxidation can be produced by a conventional method, for example, by alkylating an aromatic compound with an olefin.

When separating phenols and aldehydes or ketones produced by the method of the present invention, conventional methods,
For example, fractional distillation may be used.

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples.

The raw materials and products in the examples were analyzed by infrared spectrophotometry, gas chromatography, high performance liquid chromatography, and iodometry.

Example 1 A pressure-resistant ampoule tube with a capacity of 2 cc was charged with ethylbenzene solution Ice of 7.5% by weight of ethylbenzene hydroperoxide and 2.4 to 2.4% of niline trisulfide, and immersed in an oil bath at 150°C.

After the container was immersed for 3 minutes, it was taken out, thoroughly cooled in water, and the product was analyzed.

The results were a reaction rate of ethylbenzene hydroperoxide of 100% and a yield of phenol of 91.8%, with no formation of resinous substances observed at all.

Example 2 In a pressure-resistant ampoule tube with a capacity of 2 cc, 1 cc of a 12.4% by weight ethylbenzene solution of p-ethyl ethylbenzene hydroperoxide synthesized from p-ethyl-α-7enethyl alcohol using 90% hydrogen peroxide and Niline sulfide 2.4~ was charged and immersed in an oil bath at 150°C.

After the container was immersed for 3 minutes, it was taken out, thoroughly cooled in water, and the product was analyzed.

The results showed that the reaction rate of p-ethyl ethylbenzene hydroperoxide was 100%, and the yield of p-ethylphenol was 9.
It was 6.1%.

Example 3 A pressure-resistant Alnol tube with a capacity of 2 cc was charged with 8.2% by weight ethylbenzene solution of cumene hydroperoxide and 2.4 to 2.4% of niline trisulfide, and immersed in an oil bath at 150°C.

After the container was immersed for 3 minutes, it was taken out, thoroughly cooled in water, and the product was analyzed.

The result is that the reaction rate of cumene hydroperoxide is 100.
%, the yield of phenol was 88.3%.

Claims (1)

[Claims] 1. A method for producing phenols, which comprises decomposing a secondary or tertiary alkyl aromatic hydroperoxide to produce phenols in the presence of phosphorus sulfide.