JPS59196835A - Production of diphenyl ether compound - Google Patents

Abstract

PURPOSE:To produce the titled compound which is an organic chemical useful as a raw material of perfumery, heat transfer medium, etc., directly from a phenolic compound in vapor phase, in high selectivity, by using titanium oxide or zirconium oxide as a catalyst. CONSTITUTION:The objective compound can be prepared by contacting the phenolic compound of formula (R<1> and R<5> are H or lower alkyl), e.g. phenol, 2,3- xylenol, etc. with a catalyst comprising titanium oxide (preferably anatase-type titanium dioxide) or zirconium oxide, in vapor phase at 250-500 deg.C, preferably 350- 450 deg.C. The contact of the raw material with the catalyst is carried out e.g. by filling the catalyst in a reactor, and introducing the vapor of the heated and evaporated raw material into the reactor. The side reactions can be suppressed when steam is present together with the phenolic compound in the system. The presence of hydrogen in the system elongates the life of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for using diphenyl ethers.

Diphenyl ether is an organic chemical useful as a raw material, and a method for producing it has been found to be completely satisfactory. So far known methods for producing diphenyther include, for example,
■Fue/Sodium hydroxide to sodium fue/
a method of reacting this with benzene bromide;
■Potassium hydroxide, phenol and chlorochloride, Vo
l 79, 104842, '73), ■ Oxidizing phenol) A method of reacting in the presence of a catalyst.
(Chemical Abstract, Vol 36, p37
92, n 142, same Vo163, p9872,'
65 and JP-A Shoji 51-101941).

However, methods ■ and ■ require alkali metal hydroxides, and unnecessary alkali metal halides are produced as a by-product, creating problems in the treatment of wastewater containing these. Nasona/Shi The disadvantage is that it comes with restrictions.

As a result of studying methods for producing diphenyl ethers that do not have the above drawbacks, the inventors of the present application discovered that diphenyl ethers can be obtained directly from phenols with good selectivity by using titanium oxide or zirconium oxide. I was able to complete my invention.

That is, the present invention is characterized in that phenyls (A)R (in the formula, R1 to R5 represent hydrogen or a lower alkyl group) are brought into contact with titanium oxide or zirconium oxide in a gas phase. This is a method for producing diphenyl ethers.

The phenols [A] used in the present invention are H (a+ to R5 are hydrogen or lower alkyl, and the alkyl group is a methyl group, ethyl group, propyl group, isopropyl group, etc.). Phenols [A
] Specifically, for example, phenol, 0-cresol,
m-cresol, p-cresol, 2,di-xylenol, 5,4-xylenol/'', 2 + 4-xylenol, 2.6-xylenol, 3,4.5-
Trimethyllevenol, 2,4.6
- To'J Methylref F-F, p.
- Ethyl phenol, p-propylphenol, p-isopropylphenol, etc. can be mentioned. These can be used alone or in combination of two or more.

In the present invention, it is necessary to bring the phenols into contact with the catalyst in the gas phase. This is because a sufficient conversion rate of pheno-JVs cannot be obtained in the liquid phase state.

In the present invention, the titanium oxide used as a catalyst is titanium dioxide, and either a naturally occurring product or a synthetic product can be used. Among these titanium oxides, it is preferable to use anatase type titanium dioxide. Methods for producing anadase-type titanium dioxide include a method of igniting orthotitanic acid or metatitanic acid; an aqueous solution of titanium salts such as titanium halides, titanium nitrate, titanium sulfate, titanyl sulfate, titanium oxalate, and titanyl oxalate; By hydrolyzing titanium alkoxides such as tert-butyl titanate, titanium tetramethoxide, etc. Examples include a method in which the obtained hydroxide is precipitated and separated and then ignited. Among these, it is preferable to use titanium oxide produced by igniting a hydroxide obtained by hydrolyzing titanium salt or titanium a/L/koxide.

On the other hand, zirconium oxide may belong to any crystal system. Examples of zirconium oxide include zirconium tetrachloride, zirconyl oxychloride, ruconium oxalate,
A method of thermally decomposing salts such as zirconyl nitrate at 400 to 700°C. Alternatively, the above salt can be mixed with NaOH, KOH,
It is prepared by neutralizing with aqueous ammonia or the like, drying the resulting zirconium hydroxide at 100°C, and then firing it at 400 to 700°C.

These catalysts may contain impurities or other metal oxides as long as the effects of the present invention are achieved.

Both can be used alone or simply mixed. Furthermore, these may be supported on other inorganic materials such as activated carbon, silica, magnesia, and α-alumina.

In order to bring phenols into contact with titanium oxide or zirconium oxide in the gas phase, for example, a method is used in which a catalyst is filled in a reactor, and the heated vaporized vapor of phenols is introduced into the reactor and brought into contact in a heated state. All you have to do is take .

In this case, it is preferable to use an inert gas such as nitrogen or vapor of an aromatic hydrocarbon such as benzene, toluene, mesitylene, etc. as a carrier gas for the phenol. The concentration of phenols in the carrier gas in this case is usually about 5 mol% to 70 mol%, preferably 20 mol% to 60 mol%, although it depends on other conditions. Further, it is preferable that water vapor be present in the reaction system together with the phenol for the purpose of suppressing side reactions. In this case, the effective amount of water vapor is usually 0.01 to 0.3 mol, preferably 0.05 to 0.3 mol, per 1 mol of Fe/-/Si.

Furthermore, in order to prolong the life of the catalyst, it is preferable that hydrogen be present in the reaction system. In this case, the effective amount of hydrogen is usually 0.1 to 4 mol, preferably 0.6 to 2 mol, per 1 mol of phenol.

As the reactor, those normally used for gas phase solid catalyst reactions can be used as is.

The reaction temperature is usually 250 to 500°C, preferably 3
50 to 450°C. The reaction is generally carried out at or near normal pressure, but may be carried out under reduced pressure or increased pressure, if desired.

Although the contact time varies depending on the type of catalyst, reaction temperature, etc.9, it is preferably determined based on the conversion rate of phenols of about 5, and is usually about 0.1 to 100 seconds.

The reacted gas mixture is cooled, the carrier gas etc. are separated, and then a common separation means such as distillation is applied to obtain the target product, diphenyl ethers. That is, in addition to diphenyl ethers, the reaction product contains
Small amounts of dibenzofurans, phenylphenols, diphenylphenols, etc. may be produced as by-products, but these can be easily separated by distillation.

According to the present invention, diphenyl ethers can now be produced directly from phenols with good selectivity.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to examples, but these are not intended to limit the present invention.

Example 1 Commercially available diyv nitric acid (zro(No3)2-2
100 g of H2o) was dissolved in 11 water, and 25% ammonia water was added while stirring well until the pH of the solution became 9. The resulting white colloid was filtered, washed thoroughly with water, dried at 110°C for 15 hours, and then heated at 500°C in air.
C. for 6 hours to prepare zirconium dioxide.

The thus obtained zirconium dioxide was self-pulverized and sieved to 20 to 52 meshes, and 20+J was filled into a reaction tube made of Noxilex with an inner diameter of 25 mm, and reacted in a conventional fixed bed flow type apparatus.

That is, after raising the temperature of the catalyst layer to 400°C, a mixed solution containing phenol, water and benzene in a ratio of 1:[1,223 mol] was supplied using a metering pump, and after being gasified using a vaporizer. , passed through the catalyst layer.

The liquid hourly space velocity LH8V at this time was Q, 5 hr.

The product was analyzed by gas chromatography. The results are shown in Table 1. Example 2 The reaction was carried out in exactly the same manner as in Example 1 except that hydrogen was allowed to coexist in the reaction system. In this case, the amount of hydrogen was 0.3 mol per 1 mol of hydrogen, which was passed through at a constant flow rate of 51. The results are shown in Table 1.

Example 6 Commercially available isopropyl titanate was dissolved in about 5 times the weight of isopropylene alcohol, and water was added little by little at room temperature while stirring well. After adding 10 times the mole of water, stop stirring, filter the white slurry produced, and repeat the washing with water. When no alcohol is detected in b:5yv, the washing is finished and 80゜It was dried at C for about 30 hours. Metatitanic acid [T10(QH)2] thus obtained
] was fired in air at 500°C for 3 hours, and then cooled in a nitrogen atmosphere to prepare titanium oxide (T i 02). This titanium oxide was crushed and sieved to 62 to 64 meshes, and 20+J was charged into Pyrex reaction I), and as in Example 2, PhOH/1 (20/■(2/benzene 1:0. 2:0.3:5 moles were introduced and reacted.The results are shown in Table 1.

Example 4 Except for using p-cresol instead of phenol,
All reactions were conducted in the same manner as in Example 2. The results are shown in Table 2.

Example 5 The reaction was carried out in the same manner as in Example 2, except that 6,4-xyleno-N was used as the phenol glue.

The results are shown on the table.

Comparative Example 1 After crushing am Kagakusha +1i1 silica alumina N-651 beret into 20 to 32 meshes, sieving and 20 m1
was filled into the reaction tube. A dehydration condensation reaction of 7 enols was carried out in the same manner as in Example 2. The results are summarized in Table 1.

Comparative Example 2 Using silica alumina N-631 manufactured by JGC Chemical Co., Ltd., p-talesol was subjected to dehydration condensation. The results are shown in Table 2 Comparative Example 6 A coarse grain product of Kyowa Kagaku Kyowa Mag 150 was crushed and sieved, and subjected to a dehydration condensation reaction in the same manner as in Example 2. The results are shown in Table 1.

Comparative example 4

Claims (1)

[Claims] (1) Phenyl ether gJ characterized by contacting phenols CA) H (in the formula, R1 to R5 represent hydrogen or lower alkyl groups) with titanium oxide or ruconium oxide in the gas phase.
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