JPS6330293B2 - - 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 relates to 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 the ortho position of phenols with olefins, a method using aluminum phenoxide as a catalyst is known (Japanese Patent Publication No. 7535, 1973, etc.) and has been put to practical use.
However, in this method, the product obtained when a phenol having two alkylatable ortho positions is alkylated is a mixture of a monoalkylated product and a dialkylated product, and it is difficult to selectively produce only one of them. was difficult. Alternatively,
A method using cerium (Special Publication No. 53-24408), a method using zirconium phenoxide (Special Publication No. 1977-24408)
-19489), but these catalysts are expensive and difficult to recover and reuse, resulting in high catalyst costs. In addition, γ-
A method using an alumina catalyst (Japanese Patent Publication No. 39-5021) and its improvement method, a method using a polycondensate of aluminum alkoxide as a catalyst (US Patent No. 3733365)
is also known, but it has disadvantages as an industrial production method, such as insufficient selectivity to monoalkylated products and low catalytic activity, requiring high temperature and high pressure reaction conditions. Ta. 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,
Formula Al(R) ₃ [wherein each R is hydrogen, chlorine, bromine, iodine, a C ₁ to _{C 6} alkyl group, a C ₁ to C ₆ alkoxyl group, a C ₆ to _{C 12} aryl group, and a C _{6 -C12} aryloxyl groups. The compound obtained by reacting the aluminum compound represented by We discovered that the selectivity for alkylating only one ortho position of phenols is superior to that of known catalysts, and that it is also possible to separate the catalyst after the reaction and use it repeatedly. Ta. The present invention was completed based on such new knowledge, and it is a catalyst for producing orthoalkylphenols by alkylating the ortho position of phenols having at least one hydrogen atom at the ortho position with olefin. An orthoalkyl product characterized by using a reaction product of an aluminum compound represented by the following formula [] Al(R) ₃ [] [R is the same as above] and a C ₈ to C ₁₂ aromatic polycarboxylic acid. This is a method for producing phenols. The phenols used in the production of orthoalkylphenols in the present invention are hydroxybenzene compounds having at least one hydrogen atom at the ortho position, such as phenol, ortho-cresol, metacresol, para-cresol. , orthoethylphenol, paraethylphenol, etc. Olefins include ethylene, propylene,
Examples include 1-butene, 2-butene, isobutylene, isoamylene, cyclohexene, isooctene, and styrene, among which propylene, 1-butene, and isobutylene are frequently used. The aluminum compound used in the method of the invention has the general formula Al(R) ₃ (R is the same as above).
For example, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-isopropylaluminum, tri-isobutylaluminum, diethylaluminium ethoxide, aluminum triisopropoxide, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminum sesqui Examples include chloride, aluminum chloride, diethylaluminum hydride, and the like. Among these, particularly preferred are trialkylaluminums such as triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, and triisobutylaluminum. The aromatic polycarboxylic acid is a C ₈ to _{C 12} aromatic compound having at least two or more carboxyl groups bonded to a carbon atom of an aromatic ring,
For example, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, 2,6-
Examples include naphthalene dicarboxylic acid,
Among them, terephthalic acid is preferred. The catalyst used for reacting phenols with olefins in the process of the invention is prepared from the aluminum compound described above and an aromatic polycarboxylic acid. To prepare the catalyst, the aromatic polycarboxylic acid is dissolved or suspended in a suitable solvent, for example tetrahydrofuran, and the aluminum compound is dissolved therein either neat or in a suitable solvent, for example tetrahydrofuran. Mix. At this time, the aluminum compound and the aromatic polycarboxylic acid generally react with heat generation. Although the reaction can be carried out satisfactorily at room temperature, it can also be carried out by heating to a higher temperature such as 60°C or sometimes 250°C. The amount of aluminum compound mixed with aromatic polycarboxylic acid varies depending on the type of aromatic polycarboxylic acid, but generally 0.4 to 1.0 of aluminum compound is mixed per carboxyl group of aromatic polycarboxylic acid. By mixing molecules, compounds with excellent catalytic performance can be prepared. It is desirable to remove the excess aluminum compound after the reaction with the aromatic polycarboxylic acid by washing with a solvent such as tetrahydrofuran or by evaporating it under heat. The compound thus obtained can be used as is as a catalyst. In addition, by heating the obtained compound in the presence of phenols, alkyl groups and aryl groups derived from aluminum compounds,
Although an alkoxyl group, hydrogen, chlorine, bromine or iodine may be substituted with an aryloxyl group and then used as a catalyst, the substitution of a group derived from such an aluminum compound makes the compound catalytic without any special substitution operation. It goes without saying that this will inevitably occur in the reaction system when used as 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 3.0 moles, preferably 0.5 to 2.0 moles of olefins per mole of phenols. The amount of catalyst used varies depending on the type of raw materials and reaction conditions, but usually a sufficient effect can be obtained with a catalyst amount of 1 to 50% (by weight) based on the amount of phenols. Reaction conditions vary depending on the type of raw materials used, but the reaction temperature is generally 70 to 300℃, especially 100℃ to
250℃, reaction pressure is atmospheric pressure ~ 100Kg/cm ² , especially 2 ~
70Kg/cm ² gives good results. When the reaction is carried out under such reaction conditions, the reaction is completed in 0.2 to 10 hours. Although the chemical structure of the reaction product of the aluminum compound and aromatic polycarboxylic acid used as a catalyst in the present invention is not clear, it is a mixture of monocarboxylate, dicarboxylate, and tricarboxylate of aluminum, and has an aromatic It is considered to be a polymer compound with a complex structure in which group polycarboxylic acids are crosslinked via aluminum atoms. The reason why monoalkylation at the ortho position exhibits high selectivity has not been elucidated, but when using this catalyst, the production ratio of the monoalkylated product at the ortho position relative to the total amount of all alkylated products is
It can reach 80% or more, and depending on the reaction conditions, it can reach 98%. Note that the compound of aluminum compound and aromatic polycarboxylic acid may be soluble or insoluble in the reaction solution depending on the type of aromatic polycarboxylic acid used, but in both cases, the method of the present invention can be used. It is effective as a catalyst. If the aromatic polycarboxylic acid used is, for example, isophthalic acid, the catalyst will dissolve in the reaction solution, but if the aromatic polycarboxylic acid used is, for example, terephthalic acid, trimellitic acid, trimesic acid, or pyromellitic acid, the catalyst will not dissolve in the reaction solution. It can be easily separated and recovered from the product and used repeatedly. The orthoalkylphenols advantageously obtained by the method of the present invention have important industrial uses. For example, 2-t-butylphenol produced from phenol and isobutylene is used as a raw material for synthetic resins and insecticides, and 2-s-butylphenol produced from phenol and 1-butene is used as a raw material for agricultural chemicals. 6-tert-butyl-3-methylphenol, which is produced from 6-t-butyl-3-methylphenol, is used as a fragrance intermediate, and 6-t-butyl-3-methylphenol is produced from 6-isopropyl-, which is produced from metacresol and propylene.
3-Methylphenol is used as a raw material for medicine and menthol. Example 1 20 ml of tetrahydrofuran was added to 3.7 g of terephthalic acid, and while stirring, 20 ml of a tetrahydrofuran solution containing 2.5 g of triethylaluminum was added dropwise over about 40 minutes, followed by boiling and refluxing for 1 hour. The resulting precipitate was washed five times with 20 ml of tetrahydrofuran to remove excess triethylaluminum, and then dried under reduced pressure to obtain 4.2 g of a white powdery catalyst. Next, 20g of phenol, 20g of isobutylene,
4 g of the above catalyst was sealed in a pressure-resistant reaction vessel and reacted at 150° C. for 70 minutes with stirring. After the reaction, the pressure-resistant reaction vessel was cooled to release unreacted isobutylene, and the contents were filtered in a stream of dry nitrogen to separate the catalyst dispersed in the product. Table 1 shows the results of gas chromatography analysis of the filtrate (crude product). Example 2 The catalyst separated after the reaction in Example 1 was returned to the reaction vessel, and 20 g of phenol and 20 g of isobutylene were newly added.
was added, and the reaction was again carried out at a reaction temperature of 150°C for 70 minutes. The catalyst was repeatedly used by repeating such operations. The results are shown in Table 1.

[Table] Example 3 In Example 1 and Example 2, 23 g of metacresol was used instead of phenol, and the reaction time was
The same operations as in Example 1 and Example 2 were performed except that the time was 120 minutes. The results are shown in Table 2.

[Table] Example 4 The same procedure as in Example 1 was carried out except that 1-butene was used instead of isobutylene and the reaction was carried out at a reaction temperature of 200°C for 10 hours, and a crude product with the following composition was obtained. Obtained. Unreacted phenol 47.6 mol% 2-s-butylphenol 50.7 〃 4-s-butylphenol 0.9 〃 2,6-di-s-butylphenol
0.2 〃 2,4-di-s-butylphenol
0.3 〃 2,4,6-tri-s-butylphenol
0.2 〃 Example 5 The same operation as in Example 1 was performed except that 18 g of propylene was used instead of isobutylene in Example 1, and the reaction was carried out at a reaction temperature of 200°C for 5 hours, to obtain a crude product with the following composition. . Unreacted phenol 74.8 mol% 2-isopropylphenol 23.4 2,6-di-isopropylphenol
0.1 Other 1.7 mol% Example 6 In Example 1, 23 g of metacresol was used instead of phenol, and 18 g of propylene was used instead of isobutylene.
A crude product having the following composition was obtained by carrying out the same operation as in Example 1 except that the reaction temperature was 250° C. and the reaction was carried out for 2 hours. Unreacted metacresol 61.6 mol% 6-isopropyl-3-methylphenol
34.8 〃 Others 3.6 〃 Example 7 The same procedure as in Example 1 except that 46 g of trimellitic acid was used instead of terephthalic acid in Example 1, 1-butene was used instead of isobutylene, and the reaction was carried out at a reaction temperature of 200°C for 2 hours. I did this. The results are shown in Table 3. Example 8 The same procedure as in Example 1 was performed except that 4.6 g of trimesic acid was used instead of terephthalic acid, 1-butene was used instead of isobutylene, and the reaction was carried out at a reaction temperature of 200°C for 2 hours. . The results are shown in Table 3. Example 9 The same procedure as in Example 1 was carried out, except that 5.6 g of pyromellitic acid was used instead of terephthalic acid, 1-butene was used instead of isobutylene, and the reaction was carried out at a reaction temperature of 200°C for 2 hours. . The results are shown in Table 3.

[Table] Example 10 3.7 g of terephthalic acid and 4.5 g of aluminum triisopropoxide were added to 20 ml of tetrahydrofuran, and the mixture was boiled and refluxed for 10 hours. The resulting precipitate was washed five times with 20 ml of tetrahydrofuran to remove excess aluminum isopropoxide, and dried under reduced pressure to obtain a white powdery catalyst. 4 g of the catalyst thus prepared, phenol
20 g of isobutylene and 20 g of isobutylene were sealed in a pressure-resistant reaction vessel, and reacted at 150° C. for 5 hours with stirring.
After the reaction, the pressure-resistant reaction vessel was cooled to release unreacted isobutylene, and the contents were filtered in a stream of dry nitrogen to separate the catalyst. Return the separated catalyst to the reaction vessel and add 20 g of phenol and 20 g of isobutylene.
g was added thereto, and the reaction was again carried out at a reaction temperature of 150°C for 5 hours. The results are shown in Table 4.

[Table] Example 11 3.7g of terephthalic acid, 3g in 20ml of toluene
of anhydrous aluminum chloride was added, the temperature was raised to 100°C, and this temperature was maintained for 5 hours. After washing the resulting precipitate twice with 50 ml of toluene, 20 g of phenol was added and the mixture was boiled and refluxed at the boiling point of phenol for 48 hours. After cooling, add 50 ml of tetrahydrofuran to
After washing twice, the catalyst was dried under reduced pressure to obtain a catalyst in the form of pale yellow powder. 4 g of the catalyst thus prepared, phenol
20g of isobutylene and 20g of isobutylene were sealed in a pressure-resistant reaction vessel, and reacted with stirring. Reaction temperature 150℃,
Table 5 shows the results of repeated use of the catalyst under the reaction conditions of a reaction time of 70 minutes.

[Table] Example 12 The same operation as in Example 1 was carried out except that isophthalic acid was used instead of terephthalic acid. Since the catalyst did not dissolve in tetrahydrofuran, the catalyst preparation method was similar to that in Example 1, but unlike the catalysts used in Examples 1 to 11, the catalyst used in this example did not dissolve in the crude product. Since the catalyst was dissolved in the catalyst, the operation for separating the catalyst after the reaction in Example 1 was omitted. The crude product was analyzed by gas chromatography and the results were as follows. Unreacted phenol 16.1 mol% 2-t-butylphenol 69.9 〃 4-t-butylphenol 2.4 〃 2,6-di-t-butylphenol
1.1 〃 2,4-di-t-butylphenol
6.4 Others 4.1 Comparative Example 1 20 g of phenol and 0.1 g of aluminum pieces were sealed in a pressure-resistant reaction vessel and heated to 160°C to prepare a mixture of aluminum phenoxide and phenol. After cooling, 20 g of isobutylene was added, and the mixture was reacted at 150° C. for 30 minutes with stirring. After the reaction, the pressure-resistant reaction vessel was cooled to release unreacted isobutylene, and the contents were analyzed by gas chromatography, and the composition was as follows. Unreacted phenol 10.6 mol% 2-t-butylphenol 55.7 2,6-di-t-butylphenol
28.9 〃 2,4-di-t-butylphenol
1.8 〃 Other 3.0 〃

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, the following formula [] Al(R) ₃ is used as a catalyst. [] [In the formula, each R is hydrogen, chlorine, bromine, iodine, C ₁ ~
_C6 alkyl group, _C1 - _C6 alkoxyl group, _C6
Each may be independently selected from the group consisting of _-C12 aryl groups and _C6 - _C12 aryloxyl groups. ] and C ₈ to C ₁₂
A method for producing orthoalkylphenols, characterized by using a reaction product of the above with an aromatic polycarboxylic acid. 2. The manufacturing method according to claim 1, wherein the aromatic polycarboxylic acid is terephthalic acid.