JPH07108868B2 - Method for producing 2-tert-butyl-4-methylphenol - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

TECHNICAL FIELD The present invention relates to a method for producing 2-tertiarybutyl-4-methylphenol by debutylating 2,6-ditertiarybutyl-4-methylphenol. 2-tert-butyl-4-methylphenol (hereinafter,
Abbreviated as 4M2B. ) Is used as an intermediate for antioxidants, stabilizers, ultraviolet absorbers, agricultural chemicals, and dyes.

[Prior art and problems]

2,6-Ditertiarybutyl-4-methylphenol (4M2
Abbreviated as 6B. The method for producing 4M2B by the debutylation reaction of) is well known, and generally, as a catalyst used at that time, sulfuric acid, aluminum phenolate,
In addition to aluminum cresolate, diatomaceous earth, clay, silica-alumina, etc. are known. However, these catalysts, for example, in the case of sulfuric acid, cause debutylation and react with themselves to produce phenolsulfonic acid as a by-product, which not only leads to a decrease in yield, but also the obtained 4M2B is distilled or the like. Neutralization treatment is necessary before taking out, but the inorganic salt generated at this time is often an obstacle to the smooth progress of the distillation operation. In view of the above circumstances, the present inventors have conducted extensive studies, and surprisingly, used a heteropolyacid amount of 0.01 to 0.5% by weight with respect to 4M26B, and a reaction temperature of 160 to 280.
By setting the temperature to ℃, extremely efficient, that is, high yield, high purity, good selectivity, and without side reaction,
The debutylation reaction progressed, the above problems were solved all at once, and it was found that manufacturing on an industrial scale was possible, and the present invention was completed.

[Means for solving problems]

The object of the present invention is, according to the invention, 0.01% for 4M26B.
This is accomplished by debutylating 4M26B at a temperature of 160-280 ° C in the presence of ~ 0.5 wt% 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,
Aluminium, silicon, phosphorus, tiran, 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 0.5% by weight, preferably 0.1 to 0.25% by weight, based on 4M26B. <Reaction conditions> The reaction temperature in the present invention is 160 to 280 ° C, preferably 16
The temperature is 0 to 250 ° C., and this temperature can be determined in combination with the amount of the catalyst used so that the reaction time is industrially advantageous. A reaction time of 0.5 to 4 hours is usually 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. The invention of the present invention can also 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 contact can be rendered harmless by neutralizing with an alkali such as sodium hydroxide or sodium carbonate, but the amount of alkali used here is sufficiently small as apparent from the fact that the amount of catalyst used is small. Is. 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, high-purity 4M2B can be obtained by performing ordinary distillation operation. Also, unreacted 4M26B or side-reacted p-cresol can be reused, and the total of these components to the raw material 4M26B is almost quantitative.

【The invention's effect】

The amount of the heteropoly acid used in the method of the present invention is extremely small, and after completion of the reaction, the precipitated heteropoly acid can be reused in the reaction by taking it out of the system, thereby reducing the cost of the heteropoly acid. You can 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 4M26B was placed in a flask equipped with a thermometer and a stirrer, and 0.2 parts of tungstosilicic acid (0.2 wt% to 4M26B) was added to obtain 200
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. Then, the reaction mixture was cooled and the catalyst was separated by filtration to obtain 75.8 parts of an oily substance. The composition of this oily substance was analyzed by gas chromatography and the results were as follows. 4M26B 8.3% 4M2B 90.9% p-Quezol 0.8% The recovered amount of isobutylene was 24.1 parts. The desired product, 4M26B, was obtained from the reaction mixture by distillation under reduced pressure as a fraction having a boiling point of 125-128 ° C / 20 mmHg. Example 2 100 parts of 4M26B were placed in a flask equipped with a thermometer and a stirrer, 0.1 part of tungstosilicic acid (0.1 wt% to 4M26B) was added, and 210
The temperature was raised to ° C. The temperature was kept at the same temperature for 2 hours. The distilled isobutylene gas was introduced into an acetone trap and collected. Next, the reaction mixture was cooled, washed with a small amount of alkaline water, and liquid-separated to obtain a 72.8-fold oily substance. The composition of this oily substance was analyzed by gas chromatography and the results were as follows. 4M26B 1.5% 4M2B 93.2% p-Quezol 5.3% The amount of isobutylene recovered was 27.0 parts. Examples 3 to 8 Table 1 shows the results obtained by the same reactor and reaction method as in Example 1. Comparative Example 4M26B 100 parts into a flask equipped with a thermometer and a stirrer, 9
0.1% 8% sulfuric acid was added and the temperature was raised to 180 ° C. The temperature was kept at the same temperature for 2 hours. 0.17 parts of soda ash was added at a temperature of 100 to 110 ° C., and the mixture was kept warm for 8 hours for neutralization. 74.3 parts of oil was obtained. The composition of this oily substance was analyzed by gas chromatography and the results were as follows. 4M26B 18.2% 4M2B 64.8% p-Quezol 9.5% Other 7.5% The total yield of 4M26B, 4M2B, p-cresol is as low as 92.5%,
Other components included a cresol sulfonate.

Claims (3)

[Claims] 1. A debutylation reaction at a temperature of 160 to 280 ° C. in the presence of 0.01 to 0.5% by weight of a heteropolyacid based on 2,6-ditertiarybutyl-4-methylphenol. -Method for producing tert-butyl-4-methylphenol. 2. The amount of heteropolyacid used is 0.1 to 0.25 with respect to 2,6-ditertiarybutyl-4-methylphenol.
The method of claim 1 which is weight percent. 3. The method according to claim 1 or 2, wherein the reaction temperature is 160 ° C to 250 ° C.