JPS6332341B2 - - 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 in particular, phenols having at least one hydrogen atom in the ortho position. It relates to a method for producing orthoalkylphenols 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. 46-3053 and No. 52)
-9663), but the selectivity for alkylation to the ortho position is not sufficiently high. In particular, alkylation with 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 ortho-monoalkylated products could mainly be obtained by using cerium (Japanese Patent Publication No. 19489) or cerium (Japanese Patent Publication No. 1948-24408), but these catalysts are expensive and difficult to recover and reuse, so they have not been used industrially. This was disadvantageous as a commercial manufacturing method. As a result of various studies to overcome the drawbacks of the prior art described above, the present inventors found that in the reaction of alkylating phenol with olefin, alumina or silica was converted to alumina or silica with the formula ZrR ₄ (wherein the four R's are Chlorine, bromine, iodine, C1- _C8 alkyl _group , _C3
~ _C8 alkenyl group, _C1 to _C6 alkoxyl group,
each independently selected from the group consisting of a _{C6 - C12} aryl group and a C6- _C12 aryloxyl group, and at least one of the four R's is a _C6 - _C12
is a group other than the aryloxyl group. ) The catalyst prepared by adding the zirconium compound represented by It has been found that the selectivity for alkylating only positions is superior to that of known catalysts, and furthermore, it is possible to separate the catalyst after the alkylation reaction is completed 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, a method for producing orthoalkylphenols is characterized in that a catalyst prepared by adding a zirconium compound represented by the following formula [] ZrR ₄ [] (R is the same as above) to silica is used. The phenols used to produce orthoalkylphenols in the present invention are phenols and alkylphenols having at least one hydrogen atom ortho to the hydroxyl group of the phenol. Other examples include ortho-cresol, m-cresol, para-cresol, ortho-ethylphenol, and para-ethylphenol. 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. The zirconium compound added to alumina or silica has the general formula ZrR ₄ [wherein the four Rs are chlorine,
Bromine, iodine, _C1 - _C8 alkyl group (including aralkyl group such as benzyl), _C3 - _C8 alkenyl group, _C1 - _C6 alkoxyl group, _C6 - _C12 aryl group (including alkylaryl groups such as tolyl) and _C6 - _C12 aryloxyl groups, and four R
At least one of them is a group other than a C ₆ -C ₁₂ aryloxyl group. ]. For example, zirconium tetrachloride, zirconium tetrabromide, tetraneopentylzirconium, tetrabenzylzirconium, tetraallylzirconium, tetra-
t-butoxyzirconium, triallylbromozirconium, dibenzyldichlorozirconium,
Examples include triphenoxychlorozirconium, and mixtures thereof may also be used. The catalyst used in the process of the invention is prepared by dissolving or suspending the zirconium compound in a suitable solvent, such as toluene, mixing with alumina or silica and optionally heating. The heating temperature varies depending on the type of zirconium compound used; for example, when alkyl zirconium such as tetraneopentyl zirconium is used, heating is not required, but generally 60°C to 250°C is appropriate. The amount of zirconium compound added to alumina or silica is per gram of alumina or silica.
It is preferably in the range of 0.1 to 5 mmol, but may be in excess. It is desirable to remove excess zirconium compound after reaction with alumina or silica by washing with a suitable solvent, such as hexane. The catalyst thus obtained can be used as is as a catalyst in the process of the invention. In addition, by heating the obtained catalyst in the presence of phenols, chlorine, bromine, iodine derived from zirconium compounds,
An alkyl group, an alkenyl group, an alkoxyl group, or an aryl group may be substituted with an aryloxyl group before use; however, when the group derived from such a zirconium compound is used as a catalyst without any particular substitution operation, It goes without saying that this inevitably occurs within the reaction system. The catalyst prepared by the above method has a structure in which the zirconium compound is immobilized on the surface of alumina or silica through a chemical reaction with hydroxyl groups present on the surface of alumina or silica. Conceivable. Since the zirconium compound, which is an active species, is not substantially eluted into the reaction solution,
After the reaction is completed, the catalyst can be easily separated and recovered for repeated use. 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 using the present catalyst,
The production ratio of ortho-mono-alkylated products to the total amount of all alkylated products is 70% or more, reaching about 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 by giving examples and comparative examples below. Example 1 5 g of commercially available γ-alumina (Nishio Kogyo AC-11) with a center particle size of 80 to 100 microns was heated to 200°C, and 0.1 mm
Vacuum drying was performed using Hg for 1 hour. To this was added 10 ml of toluene and 5 mmol of tetraallylzirconium, and the mixture was stirred at room temperature for 1 hour. Pass the mixture to remove the catalyst and excess zirconium compound;
After washing with 20 ml of hexane five times,
Hexane adhering to the catalyst was removed by vaporization under reduced pressure. Alumina (catalyst) activated by the above method 5
g, 20 g of phenol, and 26 g of isobutene were placed in a pressure-resistant reactor and reacted under autogenous pressure (the same applies to the following examples) at 150° C. for 150 minutes while stirring.
After the reaction, the reactor was cooled to release unreacted isobutene, and then left to stand for about 10 minutes to allow the catalyst to settle at the bottom of the reactor. The reactor was tilted and only the liquid crude product was taken out from the upper side tube, and its composition was analyzed by gas chromatography. Add 20g of phenol and 26g of isobutene to the reactor and restart.
The reaction was carried out at 150°C for 150 minutes. The catalyst was repeatedly used by repeating such operations. The results are shown in Table 1.

[Table] Example 2 The same operation as in Example 1 was performed except that tetraneopentylzirconium was used instead of tetraallylzirconium. The composition of the crude product after the first use of the catalyst was as follows. Unreacted phenol 33.6 mol% Phenyl-t-butyl ether 8.3 2-t-butylphenol 54.6 4-t-butylphenol 0.6 2,6-di-t-butylphenol 0.8 2,4-di-t-butyl Phenol 1.7 〃 Example 3 5 g of commercially available γ-alumina (Nishio Kogyo AC-11) with a center particle size of 80 to 100 microns was heated to 200°C and 0.1 mm
Vacuum drying was performed using Hg for 1 hour. 1g for this
of zirconium tetrachloride and 20 ml of toluene,
The mixture was boiled and refluxed for 48 hours at the boiling point of toluene. Then, 7 g of phenol was added, and while toluene was distilled off, the temperature was raised to a temperature at which phenol boiled, and this temperature was maintained for 48 hours. After cooling, washing with 80 ml of tetrahydrofuran was repeated five times and then drying under reduced pressure to obtain a pale purple catalyst. 5g of the above catalyst, 20g of phenol, isobutene
13 g was placed in a pressure-resistant reactor and reacted with stirring. Table 2 shows the results of repeated use of the catalyst under the reaction conditions of a reaction temperature of 160° C. and a reaction time of 300 minutes.

【table】

[Table] Comparative Example 1 The same γ-alumina used in Examples 1 to 3 was heated to 200°C and dried under reduced pressure of 0.1 mmHg for 1 hour (zirconium compounds such as Examples 1 to 3) (No processing was performed.) 5g 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 300 minutes, the composition of the crude product was as follows (if no treatment with a zirconium compound was performed, the catalyst activity was almost non-existent). It turns out that they do not have one.) Unreacted phenol 98.6 mol% 2-t-butylphenol 0.7 〃 4-t-butylphenol 0.5 〃 2,4-di-t-butylphenol 0.2 〃 Example 4 In Example 3, commercially available particles with an average particle size of 80 to 100 microns were used. A catalyst was prepared in the same manner as in Example 3, except that 80 to 100 mesh silica gel (Fuji Davison Grade 923) was used instead of γ-alumina. The same reaction operation as in Example 3 was carried out except that the above catalyst was used and the reaction time was changed to 150 minutes, and the results shown in Table 3 were obtained.

【table】

[Table] Comparative Example 2 The same silica gel used in Example 4 was
℃ and vacuum drying for 1 hour at 0.1 mmHg (no treatment with zirconium tetrachloride as in Example 4). 5g of the above dry silica gel, 20g of phenol,
13 g of isobutene was placed in a pressure reactor and reacted with stirring at 160° C. for 150 minutes. The composition of the crude product obtained was as follows. Unreacted phenol 81.8 mol% Phenyl-t-butyl ether 2.0 2-t-butylphenol 7.6 4-t-butylphenol 7.4 2,4-di-t-butylphenol 0.5 Example 5 In Example 4, isobutyl phenol The same operation as in Example 4 was performed except that 1-butene was used instead of 1-butene, the reaction temperature was 220°C, and the reaction time was 420 minutes, and the results shown in Table 4 were obtained.

[Table] Comparative Example 3 The same operation as Comparative Example 2 was performed except that 1-butene was used instead of isobutene, the reaction temperature was 220°C, and the reaction time was 420 minutes. The composition of the crude product was as follows (it can be seen that silica gel without zirconium tetrachloride treatment has low activity). Unreacted phenol 77.8 mol% Phenyl-s-butyl ether 2.5 2-s-butylphenol 19.0 4-s-butylphenol 0.3 2,6-di-s-butylphenol 0.4 Example 6 80-100 mesh silica gel (Fuji Davison Grade 923) 5g heated to 200℃, 0.1mmHg
Drying was carried out under reduced pressure for 1 hour. To this was added 1 g of zirconium tetrachloride and 20 ml of toluene, and the mixture was boiled and refluxed for 48 hours at the boiling point of toluene. Then 7g
of para-cresol was added, and while toluene was distilled off, the temperature was raised to a temperature at which para-cresol boiled, and this temperature was maintained for 28 hours. After cooling, washing with 80 ml of tetrahydrofuran was repeated five times and then drying under reduced pressure to obtain a pale purple catalyst. Put 5 g of the above catalyst, 23 g of para-cresol, and 26 g of isobutene into a pressure-resistant reactor, and while stirring,
The reaction was carried out at ℃ for 200 minutes. The crude product obtained was as follows. Unreacted para-cresol 25.8 mol% 4-methylphenyl-t-butyl ether
7.4 〃 2-t-Butyl-4-methylphenol
65.3 〃 2,6-di-t-butyl-4-methylphenol
1.1 〃

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, alumina or silica is treated with the following formula [] ZrR ₄ [ ] (In the formula, the four R's are chlorine, bromine, iodine, C ₁ ~
_C8 alkyl group, _C3 ~ _C8 alkenyl group, C1 _~
each independently selected from the group consisting of a _C6 alkoxyl group, a _C6 to _C12 aryl group, and a _C6 to _C12 aryloxyl group, and at least one of the four R's is a _C6 to _C12 A method for producing orthoalkylphenols, which comprises using a catalyst prepared by adding a zirconium compound represented by (a group other than an aryloxyl group). 2. The method according to claim 1, wherein the zirconium compound is tetraalkylzirconium. 3. The method according to claim 1, wherein the zirconium compound is tetraallylzirconium. 4. The method according to claim 1, wherein the zirconium compound is zirconium tetrachloride.