JPS635016B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing orthoalkylphenols by reacting olefins with phenols having at least one hydrogen atom in the ortho position, and particularly phenols having at least one hydrogen atom in the ortho position. This relates to a method for producing orthoalkyl phenols by selectively alkylating one ortho position of the compound with an olefin. As a method for selectively alkylating one ortho position of phenols with an olefin, there is a method using γ-alumina as a catalyst (Japanese Patent Publication No. 39-5021).
and its improvement method (Special Publications No. 46-3058 and No. 52)
-9663), but the selectivity for alkylation to the ortho position is not sufficiently high. In particular, alkylation using tertiary olefins has disadvantages such as producing an isomer mixture in which positions other than the ortho position are alkylated, and olefins polymerize to produce dimers. In addition, zirconium aryl oxide (Special public interest
It was also known that using cerium (Japanese Patent Publication No. 19489) or cerium (Japanese Patent Publication No. 53-24408), monoalkylated products at the ortho position could be obtained, but these catalysts are expensive and difficult to recover and reuse. This was disadvantageous as an industrial manufacturing method. As a result of various studies to overcome the drawbacks of the prior art methods described above, the present inventors have discovered that in the reaction of alkylating phenols with olefins,
The catalyst prepared by adding zirconium oxychloride to alumina or silica has excellent selectivity to the ortho position for alkylation, and especially for one ortho position of phenols that have two ortho positions that can be alkylated. The selectivity for alkylating only the position is superior compared to known catalysts, and further,
It has been found that it is possible to separate the catalyst after the reaction and use it repeatedly. The present invention was completed based on such new knowledge, and when producing orthoalkyl phenols by alkylating the ortho position of phenols having at least one hydrogen atom at ortho position with olefin, alumina Alternatively, it is a method for producing orthoalkylphenols, characterized by using a catalyst prepared by adding zirconium oxychloride to silica. The phenols used to produce orthoalkylphenols in the present invention are phenols and alkylphenols having at least one hydrogen atom at the ortho position of the hydroxyl group of the phenols. , ortho-cresol, meta-cresol, para-cresol, ortho-ethylphenol, para-ethylphenol, and the like. Olefins include ethylene, propylene,
Examples include 1-butene, 2-butene, isobutene, isopentene, cyclohexene, styrene, and α-methylstyrene, among which isobutene, propylene, and 1-butene are frequently used. The alumina used in the method of the present invention includes:
Although commercially available alumina catalysts, activated alumina, etc. can be used, synthetic alumina consisting entirely or mostly of γ-alumina is particularly preferred. There are no particular limitations on the silica, and an amorphous silicic acid polymer called silica gel can be used, with silica gel for catalyst carriers and silica gel for adsorption being particularly preferred. Zirconium oxychloride added to alumina or silica can be used regardless of the amount of hydration, but the readily available octahydrate (ZrOCl ₂
8H ₂ O) is convenient and preferred. The catalyst used in the process of the invention is prepared by impregnating the alumina or silica with a zirconium oxychloride solution, drying and boiling in phenols. Zirconium oxychloride can be dissolved in water or dilute hydrochloric acid and added to alumina or silica to impregnate it. Impregnation amount is 1g of alumina or silica
The most preferred range is from 0.1 to 5 mmol.
After impregnation, it is desirable to evaporate most of the moisture at a temperature around 100°C, and then thoroughly dry the material under reduced pressure at a temperature of 180 to 250°C. A catalyst with good performance can then be prepared by adding enough phenols to fully soak the dried material and boiling for 5 hours or more at a temperature close to the boiling point of the phenols. When using the catalyst prepared by the above method,
Since active species of the catalyst are not substantially eluted into the reaction solution, the catalyst can be easily separated and recovered after the reaction is completed for repeated use. Although the structure of the catalyst has not yet been fully elucidated, aluminum atoms on the alumina surface or silicon atoms on the silica surface bond to zirconium atoms via oxygen atoms, and the zirconium atoms further chemically bond to aryloxyl groups. It is thought that the In the present invention, although the relationship between the selectivity of monoalkylation to the ortho position and the catalyst structure is not yet clear, when the present catalyst is used, the production of monoalkylated products at the ortho position relative to the total amount of all alkylated products. The ratio is over 70% and even reaches 95%. The method of the present invention is carried out by reacting phenols with olefins in the presence of the catalyst prepared as described above. The ratio of phenols to olefins is 0.3 to 5 moles, preferably 0.5 to 2 moles of olefins per mole of phenols. The amount of catalyst used varies depending on the type of raw materials and reaction conditions, but good results are usually obtained with 2 to 200% (by weight) of the amount of phenols, especially 5 to 100% (by weight). It is advantageous to use Reaction conditions vary depending on the type of raw materials used, but the reaction temperature is generally 70 to 350℃, especially 100 to 300℃.
℃, reaction pressure is atmospheric pressure ~ 150Kg/cm ² , especially 2 ~ 100
Kg/cm ² gives good results. When the reaction is carried out under such reaction conditions, the reaction is completed in 0.5 to 10 hours. In the present invention, the alkylation reaction can be carried out either batchwise or continuously. As continuous methods, fixed bed, suspended bed or fluidized bed methods are possible. The orthoalkylphenols advantageously obtained by the method of the present invention have important industrial uses. For example, 2-t-butylphenol, which is produced from phenol and isobutene, is used as a raw material for synthetic resins, insecticides, and fragrances, and 2-s-butylphenol, which is produced from phenol and 1-butene, is used as a raw material for agricultural chemicals. 6-t-butyl-3-methylphenol produced from cresol and isobutene and 2-t-butyl-4-methylphenol produced from p-cresol and isobutene are used as raw materials for antioxidants and the like. The present invention will be explained in more detail below by giving examples and comparative examples. Example 1 Zirconium oxychloride octahydrate (ZrOCl ₂ .
Dissolve 1 g of 8H ₂ O) in 10 ml of water, and the central particle size is 80~
100 micron commercially available γ-alumina (Nishio Kogyo AC-
11) Added to 10g. After drying by evaporation at 100℃, the temperature is gradually increased under reduced pressure, and the final temperature is 200℃ and 0.1mmHg.
It was dried for 1 hour. Add 10 g of phenol to this, boil for 24 hours at the boiling point of phenol, cool, and wash with 80 ml of tetrahydrofuran for 5 minutes.
This was repeated several times and then dried under reduced pressure. 10g of catalyst prepared as above, 20g of phenol
g and 13 g of isobutene were placed in a pressure-resistant reactor and reacted under autogenous pressure (the same applies to the following examples) at 170° C. for 340 minutes with stirring. After the reaction, the reactor is cooled and unreacted isobutene is released.
The catalyst was allowed to settle at the bottom of the reactor for 10 minutes, and the reactor was tilted to take out only the liquid crude product from the upper tube, and its composition was analyzed by gas chromatography. Added 20g of phenol and 13g of isobutene.
was placed in the reactor and reacted again at 160°C for 340 minutes. The catalyst was repeatedly used by repeating such operations. The results are shown in Table 1.

【table】

[Table] Example 2 In Example 1, 80 to 100 mesh silica gel (Fuji Davison Grade 70) was used instead of commercially available γ-alumina with an average particle size of 80 to 100 microns.
The same procedure as in Example 1 was carried out, except that 1-butene was used instead of isobutene, the reaction temperature was 220°C, and the reaction time was 420 minutes. The results are shown in Table 2.

【table】

[Table] Example 3 1 g of zirconium oxychloride octahydrate was dissolved in 15 ml of 2N hydrochloric acid and added to 10 g of 80-100 mesh silica gel (Fuji Davison Grade 70).
After drying by evaporation at 100℃, the temperature is gradually increased under reduced pressure.
Finally, it was dried at 200°C and 0.1mmHg for 1 hour. 15 g of para-cresol was added thereto, and the mixture was boiled for 24 hours at the boiling point of para-cresol, cooled, washed with tetrahydrofuran, and dried under reduced pressure. 10 g of the catalyst prepared by the above method, 23 g of para-cresol, and 26 g of isobutene were placed in a pressure-resistant reactor and reacted at 160° C. for 300 minutes with stirring. The composition of the obtained crude product was as follows. Unreacted para-cresol 1.4 mol% 4-methylphenyl-t-butyl ether
0.6 mol% 2-t-butyl-4-methylphenol
87.2 mol% 2,6-di-t-butyl-4-methylphenol 10.6 mol% Comparative example 1 The same γ-alumina as used in Example 1 was
It was heated to 200° C. and dried under reduced pressure of 0.1 mmHg for 1 hour (the treatment with zirconium oxychloride as in Example 1 was not performed). 10g of the above dried γ-alumina, 20g of phenol
When 13 g of isobutene was placed in a pressure-resistant reactor and reacted with stirring at 160° C. for 340 minutes, the composition of the crude product was as follows. Unreacted phenol 98.0 mol% 2-t-butylphenol 1.2 mol% 4-t-butylphenol 0.6 mol% 2,4-di-t-butylphenol 0.2 mol% Comparative Example 2 In Comparative Example 1, instead of γ-alumina The same operation as in Comparative Example 1 was performed except that the same silica gel as used in Example 2 was used, the reaction temperature was 220° C., and the reaction time was 420 minutes, to obtain a crude product having the following composition. Unreacted phenol 99.5 mol% 2-s-butylphenol 0.4 mol% 4-s-butylphenol 0.1 mol%

Claims (1)

[Claims] 1. When producing orthoalkylphenols by alkylating the ortho position of phenols having at least one hydrogen atom at the ortho position with olefin, a catalyst prepared by adding zirconium oxychloride to alumina or silica is used. A method for producing orthoalkylphenols, characterized by: