JPS6121531B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing orthomethylated phenols such as 2,6-xylenol by reacting phenols having ortho hydrogen such as phenol and cresol with methanol. More specifically, the present invention relates to a method that can selectively methylate the ortho position and suppress the decomposition reaction of methanol, and particularly provides a highly active catalyst in the reaction. Orthomethylated phenols, such as xylenol, are used as raw materials for the production of polyphenylene oxide resins. Conventionally, these orthomethylated phenols have been produced by reacting phenols having hydrogen at the ortho position with methanol in the presence of a catalyst, and various metal oxides are effective as catalysts. is proposed. For example, Japanese Patent Publication No. 42-6894 discloses a method using magnesium oxide as a catalyst, and Japanese Patent Publication No. 51-11101 discloses a method using manganese oxide as a catalyst. Publication No. 52-47446 and British Patent No. 717588 disclose a method using iron oxide as a catalyst. Among these metal oxide catalysts, the method of using magnesium oxide catalysts has high ortho-position selectivity for the methylation reaction, but if the reaction is carried out at high temperatures to increase catalytic activity, the life of the catalyst will be shortened. However, since the catalyst is easily powdered, it is inconvenient to handle. Therefore, in order to improve these drawbacks of magnesium oxide catalysts, methods using various multi-component catalysts consisting of magnesium oxide and other metal oxides have been proposed, but these methods have not yielded fully satisfactory results. It's hard to say that it is. In addition, in the method of using iron oxide as a catalyst, the iron oxide catalyst has the characteristic that it shows high activity at a lower temperature than the magnesium oxide catalyst, but the ortho position selectivity of the methylation reaction is not sufficiently high. Further, there are disadvantages such as a large amount of methanol being decomposed during the reaction, and furthermore, the activity of the catalyst is greatly reduced and the catalyst life is short. In order to improve these drawbacks of iron oxide catalysts, methods using various multi-component catalysts consisting of iron oxide and other metal oxides have been proposed (for example, Japanese Patent Publication No. 46-37812; 47-37943 Publication, Special Publication No. 47-37944, Special Publication No. 47-37945,
Special Publication No. 47-37946, Publication No. 7020-7020, Publication No. 5696-50, Publication No. 10023-1971, Publication No. 12610-12610, Publication No. 47446-1977
Publication No. 12689, Special Publication No. 12689, Special Publication No. 12689, Special Publication No. 12689, Special Publication No. 12689, Special Publication No. 12689
Publication No. 12690, Japanese Patent Publication No. 12692, Japanese Patent Publication No. 12692, Japanese Patent Publication No. 1973
-38936 Publication, JP-A-50-76032, JP-A-Sho
53-90229, JP-A-53-101318, etc.). However, even if these catalysts are used, the above objectives cannot be fully achieved. The present inventors have proposed a method for producing orthomethylated phenols by reacting phenols having hydrogen at the ortho position with methanol, which has high activity and high ortho position selectivity in the methylation reaction.
As a result of our deep search for a long-life iron oxide-containing catalyst that can suppress the decomposition reaction of methanol, we found that a solution of a colloidal iron compound a and a compound of gallium, germanium, yttrium, niobium, hafnium, tantalum, or bismuth, b. It has been found that the above object can be achieved by using a multicomponent catalyst consisting of iron oxide c and an oxide d of the specific metal prepared by calcining a solid mixture obtained from a dispersed mixture containing reached. Compared to conventional catalysts, the use of the catalyst of the present invention is said to be industrially advantageous because it has higher activity and ortho-selectivity in the methylation reaction, and can suppress the methanol decomposition reaction. It has characteristics. That is, the present invention provides orthomethylated phenols by reacting phenols having at least one ortho hydrogen with methanol under heating in the presence of a multicomponent catalyst containing iron oxide as a main component. A solid mixture obtained from a dispersion mixture comprising a colloidal iron compound (a) and a solution (b) of a compound of at least one metal selected from the group consisting of gallium, germanium, yttrium, niobium, hafnium, tantalum and bismuth, in the method of manufacturing. Contains at least one metal oxide d selected from the group consisting of iron oxide c, gallium oxide, germanium oxide, yttrium oxide, niobium oxide, hafnium oxide, tantalum oxide, and bismuth oxide produced by firing The method for producing orthomethylated phenols is characterized in that the reaction is carried out in the presence of a multicomponent catalyst containing an iron oxide component as a main component. The phenols used as raw materials in the method of the present invention are those having at least one ortho hydrogen. Specifically, phenols; cresols such as o-cresol, m-cresol, and p-cresol;
2,3,4-trimethylphenol, 2,3,5
-trimethylphenol, 2, trimethylphenol such as 3,4,5-trimethylphenol,
Methyl group-substituted phenols having ortho-position hydrogen such as 3,4,5-tetramethylphenol; At least one of the methyl groups of these methyl group-substituted phenols is an ethyl group, propyl group, butyl group, cyclohexyl group, phenyl group. Examples include hydrocarbon group-substituted phenols substituted with a hydrocarbon group such as a hydrocarbon group. Among these phenols having ortho hydrogen, phenol, o-
Preference is given to applying the method of the invention to cresols or mixtures thereof. In the method of the present invention, the proportion of methanol used is generally 1 to 10 mol, preferably 3 to 6 mol, per 1 mol of the phenol having ortho hydrogen. The catalyst used in the method of the invention is prepared by mixing a colloidal iron compound a and a solution b of at least one metal compound selected from the group consisting of gallium, germanium, yttrium, niobium, hafnium, tantalum and bismuth. from the group consisting of gallium oxide, germanium oxide, yttrium oxide, niobium oxide, hafnium oxide, tantalum oxide and bismuth oxide, produced by calcining a solid mixture obtained from a dispersed mixture produced by It is a multicomponent catalyst containing a second component d consisting of at least one selected metal oxide and containing an iron oxide component as a main component. The catalyst of the present invention includes, in addition to the catalyst consisting of the two components, a catalyst consisting of the second component and another metal oxide, a catalyst formed by adding various binders to the two components, or a catalyst configuration thereof. It can also be used in the form of catalysts in which the components are supported on various carriers. When the catalyst of the present invention is used as a ternary catalyst by adding a third component consisting of another metal compound to the binary catalyst consisting of the two components, the third component includes the first component and Various metal compounds other than the second component can be exemplified. As the third component, for example, magnesium oxide, zinc oxide, aluminum oxide, silicon oxide, chromium oxide, zirconium oxide, sodium oxide,
It is particularly suitable to form a ternary catalyst by blending potassium oxide, sodium carbonate, potassium carbonate, etc., since this suppresses a decrease in the activity of the catalyst and provides a long life. In the method of the present invention, the iron compound used for catalyst preparation is colloidal iron compound a. As the colloidal iron compound, either a sol iron compound or a gel iron compound can be used. Specific examples of the colloidal iron compound include colloidal iron compounds such as iron hydroxide, iron oxide, and mixtures thereof, and other colloidal substances of various iron compounds. Among these colloidal iron compounds, the main component is non-crystalline and colloidal iron hydroxide, iron oxide, or a mixture thereof in the form of a sol or gel is used to achieve high activity and methylation reaction. It is industrially advantageous since it is possible to obtain a catalyst that has high ortho-position selectivity and can suppress the decomposition of methanol. The colloidal iron compound a described above can be prepared by the following method. Among these colloidal iron compounds, sol iron compounds are usually prepared by contacting unstable metal compounds such as iron halides and alkoxides with water, or by stirring an organic solvent solution of these iron compounds with water. It can also be produced by bringing it into contact with the water and causing it to decompose. It can also be produced by reacting a base such as ammonia or an aqueous sodium hydroxide solution with a solution of relatively stable iron compounds such as iron sulfates, nitrates, phosphates, and borates. Also,
By removing the medium from the sol-like iron compound thus prepared, a gel-like iron compound can be prepared. Among the colloidal iron compounds, the sol iron compounds are preferably used for preparing the catalyst of the present invention. Further, the average particle size of these colloidal iron compounds is usually in the range of 0.5 to 20μ, preferably 1 to 10μ. In the method of the invention, the second component used for the preparation of the catalyst is a solution b of a compound of at least one metal selected from the group consisting of gallium, germanium, yttrium, niobium, hafnium, tantalum and bismuth. be. Among the metal compound solutions b, when a solution of at least one metal compound selected from the group consisting of gallium, germanium, and hafnium is used, the effect of suppressing the ortho-position selectivity of the methylation reaction and the decomposition of methanol can be improved. It is preferable to use solution b of a germanium compound because it can improve the above-mentioned effects and provide a highly active catalyst. In particular, it is preferable to use germanium compound solution b because a catalyst with the above-mentioned excellent effects can be obtained. The metal compound may be in any form as long as it is soluble in the various solvents described below, such as halides, nitrates, perchlorates, phosphates, borates, and hydroxides. Examples thereof include compounds, oxides, oxyacids, alkoxides, formates, acetates, propionates, benzoates, phenol salts, cresol salts, xylenol salts, and the like. Further, the solution of the metal compound may be a solution dissolved in any solvent. Examples of the solvent include water; organic solvents such as alcohols, ethers, and aliphatic carboxylic acids. The concentration of the metal compound in these solutions is arbitrary. Among the solutions of the metal compound, an aqueous solution, an alcohol solution, an ether solution, or an aliphatic carboxylic acid solution of the metal compound is preferable, and an aqueous solution is particularly preferable. The catalyst used in the method of the present invention comprises the colloidal iron compound a, the solution b of the metal compound, and the third component added as necessary, or a metal that can become the third component by calcination. It is produced by calcining a solid mixture obtained from a dispersed mixture produced by mixing the compounds. The dispersion mixture consisting of the colloidal iron compound a, the solution b of the metal compound, and the third component added as necessary or a metal compound that can become the third component by firing is usually a mixture of these. A uniformly dispersed mixture can be formed by stirring and mixing each of the components in a medium such as water or an organic medium. that time,
When either the colloidal iron compound a or the metal compound solution b contains a medium,
It is not necessarily necessary to add media. The average particle diameter of the dispersoid of the dispersion mixture obtained from the colloidal iron compound a and the solution b of the metal compound is usually in the range of 0.5 to 20μ, preferably 1 to 10μ. In addition, when the catalyst used in the method of the present invention is made to be a so-called supported catalyst supported on a carrier, a known carrier may be added to the uniformly dispersed mixture and mixed to form a dispersed mixture, or Furthermore, in order to improve the moldability of the catalyst used in the method of the present invention, a known binder may be added to and mixed with the uniformly dispersed mixture to form a dispersed mixture. A solid mixture is obtained by removing the medium from the dispersion mixture prepared by the method described above. Usually, this solid mixture is obtained by drying by a method such as distilling off the medium. When preparing the catalyst of the present invention as a supported catalyst, or when adding a binder to the catalyst of the present invention,
Alternatively, when the third component is added to the catalyst of the present invention, the carrier, the binder, the third component, or a metal compound that can become the third component by firing is added to the dispersion mixture forming step. Instead of the method of blending, each component of the carrier, the binder, the third component, or a metal compound that can become the third component by firing is blended into the solid mixture obtained by the above method. However, it is also possible to form a solid mixture. The catalyst used in the method of the invention is then obtained by calcining the solid mixture prepared by the method described above. During firing, this solid mixture is fired in the form of a powder, or a molded article such as a sphere, a granule, or a block. The temperature during firing is usually
The temperature range is from 300 to 900°C, preferably from 400 to 600°C. Firing is carried out either in the presence of a molecular oxygen-containing gas such as air, or in an atmosphere of an inert gas such as nitrogen gas.
It is preferable to perform the calcination in the presence of a molecular oxygen-containing gas because a catalyst with high activity and excellent ortho-position selectivity in the methylation reaction can be obtained. When preparing the catalyst of the present invention by the method described above, the blending ratio of each component when preparing a dispersion mixture containing the colloidal iron compound a and the solution b of the metal compound is as follows: The metal atoms of solution b of the compound of said metal per gram atom of iron per gram atom of said metal are usually in the range of 0.003 to 0.3 gram atom, preferably 0.005 to 0.15 gram atom. Further, when preparing a dispersion compound by blending the third component or a metal compound that can become the third component upon firing into the dispersion mixture, the blending ratio is 1 gram atom of iron atoms of the colloidal iron compound a. Usually 0.0001 to 0.1 gram atom as the metal atom constituting the third component per unit,
Preferably it is in the range of 0.001 to 0.5 gram atom. The catalyst prepared by the above method comprises iron oxide C and at least one metal oxide selected from the group consisting of gallium oxide, germanium oxide, yttrium oxide, niobium oxide, hafnium oxide, tantalum oxide, and bismuth oxide. binary component d
It is a multicomponent catalyst containing iron oxide as a main component. Specifically, iron oxide c, which is the first catalyst component of the catalyst obtained by the above preparation method, is ferrous oxide, ferric oxide, or a mixture thereof.
Among these iron oxide catalyst components, ferric oxide or a mixture with ferrous oxide is preferred. Further, the second catalyst component of the catalyst obtained by the above preparation method is at least one selected from the group consisting of gallium oxide, germanium oxide, yttrium oxide, niobium oxide, hafnium oxide, tantalum oxide, and bismuth oxide. seed metal oxide d
It is. More specifically, gallium oxide,
Gallium oxides such as gallium oxide or mixtures thereof; germanium oxides such as germanous oxide, germanium oxide or mixtures thereof; yttrium oxides such as yttrium trioxide; niobium monoxide, diniobium trioxide, niobium dioxide , diniobium pentoxide or mixtures thereof; hafnium oxides such as hafnium dioxide; tantalum oxides such as tantalum dioxide, ditantalum pentoxide or mixtures thereof; bismuth monoxide, bismuth trioxide, Bismuth oxide in various oxidation states, such as bismuth pentoxide or mixtures thereof. These metal oxide d catalyst components may be a mixture of two or more. These metal oxide d catalyst components contain at least one member selected from the group consisting of gallium oxide, germanium oxide, and hafnium oxide.
A seed metal oxide is preferable because it further improves the ortho-position selectivity of the methylation reaction and the effect of suppressing methanol decomposition. In addition, by blending the catalyst used in the method of the present invention as necessary, specific examples of the third component include magnesium oxide, zinc oxide, aluminum oxide, silicon oxide, chromium oxide,
Examples include zirconium oxide, sodium oxide, potassium oxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. A ternary catalyst containing these third components is suitable because it suppresses a decrease in catalyst activity and has a long life. The blending ratio of the second catalyst component consisting of the metal oxide b in the catalyst used in the method of the present invention is usually 0.003 to 0.3 g atoms per 1 g atom of the iron atom of the iron oxide a. ,
Preferably it is in the range of 0.005 to 0.15 gram atom. Further, when the third catalyst component is blended into the catalyst, the blending ratio is usually 0.0001 to 0.1 gram atom, preferably 0.001 gram atom of the metal atom constituting the third component per gram atom of iron of iron oxide. and 0.05 gram atom. In the method of the present invention, orthomethylated phenols are produced by reacting phenols having at least one hydrogen at the ortho position with methanol under heating in the presence of the catalyst. The reaction is usually carried out in the gas phase, but can also be carried out in the liquid phase. When the reaction is carried out in the gas phase, the reaction temperature is usually 250 to 450°C, preferably 300 to 400°C. During the reaction, the catalyst can be used as a fixed bed catalyst or as a fluidized bed catalyst. When the reaction is carried out in fixed bed mode, the liquid hourly space velocity (LHSV) of the feedstock usually ranges from 0.1 to 10 hr ^-1 , preferably from 0.5 to 5 hr ^-1 . Further, the reaction can usually be carried out under reduced pressure or increased pressure, but is preferably carried out under a pressure in the range of 1 to 30 kg/cm ² -G. After separating unreacted methanol from the reaction mixture, orthomethylated phenols can be obtained by treatment according to conventional methods such as distillation, crystallization, and extraction. The recovered unreacted methanol and phenols having ortho-position hydrogen are recycled and reused in the reaction. Next, the method of the present invention will be specifically explained using examples. The meaning of each term used below and the calculation method are as follows. Phenol conversion rate (%) = Amount of phenol supplied (mol) - Amount of unreacted phenol (mol) / Amount of phenol supplied (mol)
l) x 100 Selectivity (%) for each product generation = Amount of each component produced (mol) / Amount of phenol supplied (mol) - Amount of unreacted phenol (m
ol) × 100 Orthomethylation selectivity (%) = 2,6-xylenol selectivity + o-cresol selectivity Methanol decomposition rate (%) = 100 × (1-o-cresol production amount (mol) + 2,6-xylenol production Amount (mol) x 2/Amount of methanol supplied (mol) - Amount of final reacted methanol (mol)) Example 1 After dissolving 202.0 g of ferric nitrate nonahydrate in the distilled water from 2, 25% ammonia water was added. Gradually add
By setting the pH of the liquid to 7, amorphous and sol-like ferric hydroxide was produced. This sol-like ferric hydroxide had particle sizes distributed in the range of 1 to 10 μm (average particle size of about 5 μm). After washing the generated amorphous and sol-like ferric hydroxide with water, 1.62 g of germanium dioxide was dissolved in 2
The mixture was added to an aqueous solution of and thoroughly stirred to form a dispersion mixture containing ferric hydroxide in the form of a sol. The amount of particles dispersed in this dispersion mixture had particle sizes distributed in the range of 1 to 10 microns (average particle size of about 4 microns). After removing moisture by heating, dry at 90℃ for one day and night, then dry at 450℃
The mixture was fired for 3 hours to prepare an iron oxide/germanium oxide catalyst. 20ml of catalyst crushed into 6-10 meshes with inner diameter of 20mm
After filling the Pyrex reaction tube, the temperature was increased to 355℃.
heated to. After reaching the specified temperature, phenol:
A reaction was carried out by supplying a mixed solution of methanol:H ₂ O in a molar ratio of 1:5:2 at a rate of 30 ml/hr. The results are shown in Table 1. Example 2 Iron oxide was prepared in the same manner as in Example 1, except that instead of the aqueous solution of 2 in which 1.62 g of germanium dioxide was dissolved, an aqueous solution of 2 in which 6.19 g of gallium nitrate octahydrate was dissolved was used.・Gallium oxide catalyst was prepared. Using this catalyst, Example 1
The reaction was carried out under the same conditions. The results are shown in Table 1. Comparative Example 1 After dissolving 202.0 g of ferric nitrate nonahydrate in distilled water from step 2, 25% ammonia water was gradually added,
The pH of the liquid was set to 7. After washing the produced amorphous and sol-like iron hydroxide with water, 1.62 g of germanium dioxide powder crystals were added thereto and kneaded for 1 hour using an automatic mortar. This was dried at 90℃ for one day and night.
The mixture was then calcined at 450°C for 3 hours to prepare an iron oxide/germanium oxide catalyst. Table 1 shows the results of a reaction using this catalyst under the same conditions as in Example 1. Comparative Example 2 In the catalyst preparation of Comparative Example 1, 1.62 g of germanium dioxide was mixed with 1.45 g of gallium oxide powder crystals.
An iron oxide/gallium oxide catalyst was prepared in the same manner except that the iron oxide/gallium oxide catalyst was changed to Table 1 shows the results of a reaction using this catalyst under the same conditions as in Example 1.

[Table] Examples 3 to 7 In the catalyst preparation of Example 1, 1.62 g of germanium dioxide was mixed with 3.26 g of hafnium oxide (Example 3), 5.92 g of stotrium nitrate hexahydrate (Example 4), and 2.06 g of niobium oxide. (Example 5), 3.42 g of tantalum oxide (Example 6), and 7.50 g of bismuth nitrate pentahydrate (Example 7) were used, but catalysts were prepared in the same manner. A reaction was carried out under the same conditions as in Example 1 using these catalysts. The results are shown in Table 2. Comparative Examples 3 to 7 In the catalyst preparation of Comparative Example 1, 1.62 g of germanium dioxide was mixed with 3.26 g of hafnium oxide (Comparative Example 3), 5.92 g of yttrium nitrate hexahydrate (Comparative Example 4), and 2.06 g of niobium oxide (Comparative Example). 5), catalysts were prepared in the same manner except that 3.42 g of tantalum oxide (Comparative Example 6) and 7.50 g of bismuth nitrate pentahydrate (Comparative Example 7) were used. Using these catalysts,
The reaction was carried out under the same conditions as in Example 1. Table 2 shows the results.
Shown below.

【table】

【table】

Claims (1)

[Claims] 1. Orthomethylated phenols by reacting phenols having at least one hydrogen at the ortho position with methanol under heating in the presence of a multicomponent catalyst containing an iron oxide component as a main component. A method for producing a colloidal iron compound a
and an oxide produced by calcining a solid mixture obtained from a dispersion mixture containing a solution b of a compound of at least one metal selected from the group consisting of gallium, germanium, yttrium, niobium, hafnium, tantalum and bismuth. Iron c and gallium oxide, germanium oxide,
The reaction is carried out in the presence of a multi-component catalyst containing at least one metal oxide d selected from the group consisting of yttrium oxide, hafnium oxide, tantalum oxide and bismuth oxide and containing an iron oxide component as a main component. Characteristic method for producing orthomethylated phenols. 2. The proportion of the solution b of the metal compound in the dispersion mixture is 1 iron atom of the colloidal iron compound a.
A method according to claim 1, wherein the metal atom is in the range of 0.003 to 0.3 gram atom. 3. The method according to claim 1 or 2, wherein the colloidal iron compound a is colloidal iron hydroxide, iron oxide, or a mixture thereof. 4. The method according to any one of claims 1 to 3, wherein the colloidal iron compound a is a sol iron compound. 5. The method according to any one of claims 1 to 4, wherein the solid mixture is calcined at a temperature of 400 to 600°C. 6. Any one of claims 1 to 5, wherein the catalyst contains the metal oxide d in an amount of 0.005 to 0.15 gram atom per gram atom of iron of the iron oxide c. the method of. 7. The method according to any one of claims 1 to 6, wherein the catalyst contains 0.001 to 0.05 mol of zirconium oxide per gram atom of iron of the iron oxide a. 8. The method according to any one of claims 1 to 7, wherein the reaction is carried out in a gas phase. 9. The method according to any one of claims 1 to 8, wherein the phenol having at least one ortho-position hydrogen is phenol, o-cresol, or a mixture thereof. 10. The method according to any one of claims 1 to 9, wherein the reaction is carried out at 300 to 400°C.