JPH07108869B2 - Method for producing 3-methylphenol - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention provides 3-methyl-6- by debutylating 3-methyl-4,6-ditertiarybutylphenol.
Tertiary butylphenol (hereinafter abbreviated as 3M6B) and / or 3-methylphenol (hereinafter abbreviated as MCL)
(Hereinafter, these 3M6B and MCL are combined and referred to as 3-methylphenol). 3M6B is an antioxidant, stabilizer, UV absorber, pesticide,
It is used as an intermediate for dyes. MCL is also used as an intermediate for agricultural chemicals, dyes, heat-sensitive pigments, and stabilizers.

[Prior art and its problems]

The method for producing 3-methylphenols by debutylation of 3-methyl-4,6-ditertiarybutylphenol (hereinafter abbreviated as 3M46B) is well known,
Generally, as catalysts used at that time, there are known sulfuric acid, aluminum phenolate, aluminum cresolate and the like, as well as diatomaceous earth, clay, silica-alumina, strongly acidic ion exchange resins and the like. However, in the case of sulfuric acid, for example, these catalysts not only cause debutylation but also react with themselves to produce phenolsulfonic acid as a by-product, leading to a decrease in yield, and the resulting 3-methylphenols. Neutralization treatment is required before taking out by distillation or the like, but the inorganic salt generated at this time is often an obstacle to the smooth progress of the distillation operation. Further, the substance obtained by reacting the phenolsulfonic acid with the generated isobutylene has a bad influence during the distillation operation, and thus must be rendered harmless after the neutralization treatment, which requires a severe treatment at high temperature. In view of the above situation, the present inventors have conducted intensive studies, and as a result, have found that the use of heteropolyacid as a catalyst yields a desired product in a high yield and industrially, and completes the present invention. It has come to do.

[Means for solving problems]

The object of the present invention is achieved according to the present invention by producing 3-methylphenols by subjecting 3M46B to a debutylation reaction in the presence of a heteropolyacid. Hereinafter, the present invention will be described in detail. <Catalyst> The present invention makes it essential to use a heteropolyacid as a catalyst. The heteropolyacid referred to in the present invention means an acid produced by two or more kinds of metals among polyacids formed by combining with an inorganic acid, and generally one kind of metal (or heteroatom) as a center. , Is a general term for those formed by coordinating another metal (poly atom) through oxygen or the like. Here, as the hetero atom, boron,
Aluminum, silicon, phosphorus, titanium, germanium,
Examples include arsenic, zirconium, tin, tellurium and the like. Examples of the poly atom include molybdenum, tungsten, vanadium, niobium, and the like. Specifically, molybdophosphoric acid, molybdosilicic acid, molybdoarsenic acid, molybdoteruric acid, molybdoaluminic acid, tungstosilicic acid, tungstophosphoric acid, tungstoboric acid,
Examples thereof include tungstotitanic acid and tungstostanic acid, and of these, molybdophosphoric acid, molybdosilicic acid, tungstophosphoric acid, tungstosilicic acid and the like are preferably used. Incidentally, these heteropolyacids are usually used in the form of hydrates. The amount of the catalyst used is 0.01 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.1 to 1% by weight, based on 3M46B. <Reaction conditions> The reaction temperature in the present invention is 140 to 280 ° C, preferably 16
It is 0 to 250 ° C. When the main purpose is 3M6B, it is relatively constant temperature side, that is, 14
It may be carried out at 0 to 200 ° C, preferably 160 to 180 ° C. When the main purpose is MCL, the relatively high temperature side, that is, 160
It is good to carry out at 280 ° C, preferably 180 ° C to 250 ° C. The reaction temperature can be determined in combination with the amount of catalyst used so that the reaction time is industrially advantageous. Reaction time is normal
0.5-4 hours is sufficient. It goes without saying that the reaction mode of the present invention can be either batch mode of atmospheric pressure, pressurization or depressurization or continuous mode. Further, the reaction of the present invention can be carried out in an atmosphere of an inert gas such as nitrogen, helium or argon. <Treatment after the reaction> The treatment after the reaction is performed by separating the precipitated catalyst,
It can be reused. As a means for separation, a usual separation means such as filtration, centrifugation or decanter can sufficiently achieve the purpose. Alternatively, the catalyst can be rendered harmless by neutralizing with an alkali such as sodium hydroxide or sodium carbonate.
As a result, since there is no by-product of phenolsulfonic acids as in the case of using a sulfuric acid catalyst, it is not necessary to heat the neutralization treatment, and mild conditions are sufficient. Alternatively, the heteropolyacid present in the system can be removed by washing with water and liquid separation. After removing the catalyst or detoxifying the reaction product, a high-purity 3M6B and / or MCL can be obtained by performing an ordinary distillation operation. Further, unreacted 3M46B can be reused, and the total of these components to the raw material 3M46B is almost quantitative.

【The invention's effect】

By the heteropolyacid used in the method of the present invention, side reactions are extremely small, and after completion of the reaction, the precipitated heteropolyacid can be reused in the reaction by removing it from the system, and the cost of the heteropolyacid can be reduced. . In addition, the reaction can be carried out with an extremely high balance without impurities such as a sulfonated product as in the case of using sulfuric acid as a catalyst.

【Example】

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded. In addition, the middle part and% mean a weight part and weight%, respectively. Example 1 100 parts of 3M46B was placed in a flask equipped with a thermometer and a stirrer, 0.1 part of tungstosilicic acid (0.1% by weight to 3M46B) was added, and 160
The temperature was raised to ° C. The temperature was kept at the same temperature for 2 hours. Distilled isobutylene gas was deep-cooled and led to a trap for recovery. The reaction mixture was then cooled and the catalyst filtered off to give 74.5 parts oil. The composition of this oily substance was analyzed by gas chromatography and the results were as follows. 3M46B 5.2% 3M6B 92.5% MCL 2.3% The recovered amount of isobutylene was 25.0 parts. The desired product, 3M6B, is obtained from the reaction mixture by distillation under reduced pressure as a fraction with a boiling point of 128-131 ° C / 20 mmHg. Example 2 100 parts of 3M46B were placed in a flask equipped with a thermometer and a stirrer, 0.3 parts of tungstosilicic acid (0.3% by weight to 3M46B) was added, and 200
The temperature was raised to. The temperature was kept at the same temperature for 2 hours. Distilled isobutylene gas was deep-cooled and led to a trap for recovery. The reaction mixture was then cooled and the catalyst filtered off to give 49.0 parts of an oil. The composition of this oily substance was analyzed by gas chromatography and the results were as follows. 3M46B 0% 3M6B 1.2% MCL 97.0% The amount of recovered isobutylene was 50.2 parts.
After neutralization with soda ash, the desired product, MCL, is obtained from the reaction mixture as a fraction of 100-103 ° C / 20 mmHg by rectification under reduced pressure. Examples 3 to 8 Table 1 shows the results obtained by the same reactor and reaction method as in Example 1. Comparative Example 3M46B 100 parts in a flask equipped with a thermometer and a stirrer, 9
0.1% 8% sulfuric acid (0.1% by weight vs. 3M46B) was added and the temperature was raised to 170 ° C. The temperature was kept at the same temperature for 2 hours. 0.16 parts of soda ash was added at a temperature of 100 to 110 ° C., and the mixture was kept warm for 5 hours for neutralization. 7
1.5 parts of oil was obtained. The composition of this oily substance was analyzed by gas chromatography and the results were as follows. 3M46B 15.8% 3M6B 74.0% MCL 8.0% Other 2.2% The total yield of 3M46B, 3M6B and MCL was low at 94.0%, and cresol sulfonate was included in other components.

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Claims (5)

[Claims] 1. A method for debutylating 3-methyl-4,6-ditertiarybutylphenol in the presence of a heteropolyacid, wherein 3-methyl-6-tert-butylphenol and / or 3-methylphenol is used. Production method. 2. The amount of heteropolyacid used is 3-methyl-4,
Process according to claim 1, characterized in that it is from 0.01 to 10% by weight, based on 6-ditertiarybutylphenol. 3. The amount of heteropolyacid used is 3-methyl-4,
Process according to claim 2, characterized in that it is from 0.1 to 5% by weight, based on 6-ditertiarybutylphenol. 4. The method according to any one of claims 1 to 3, wherein the debutylation reaction temperature is 140 to 280 ° C. 5. The method according to claim 4, wherein the debutylation reaction temperature is 160 to 250 ° C.