NL8105099A - METHOD FOR ORTHO-ALKYLATION OF PHENOLIC COMPOUNDS. - Google Patents

Description

M W

Method for ortho-alkylation of phenolic compounds.

The invention relates to a process for the selective ortho-alkylation of a phenolic compound with at least one hydrogen atom at an enortho position by reacting the phenolic compound in a vapor phase catalytically with an alcohol. In this process, the reaction of the phenolic compound with the alcohol is carried out at a temperature between 0 °.

300-550 ° C in the presence of a catalyst containing manganese oxide and one or more additives selected from group (A) consisting of germanium oxide, tin oxide and lead oxide. The catalyst 10 may further contain one or more additives selected from the silica and group (B) consisting of alkali metal oxides and alkaline earth metal oxides. The catalyst used in this invention not only exhibits excellent catalytic activity in the selective orthoalkylation of phenols, continued activity stability, good formability and good mechanical strength, but also leads to effective utilization of the alcohols.

This invention relates to a method of selectively alkylating the unsubstituted ortho-position 20 or sites of phenolic compounds. The invention particularly relates to a process in which the aforementioned alkylation is carried out with excellent results and long-term stability in the presence of an improved catalyst containing manganese oxide as the main component.

The preparation of 2,6-dimethylphenol, among the other ortho-alkylated phenols, has been the subject of many studies to date, as it is a starting material for preparing polyphenylene etheis with a wide variety of applications as a heat resistant resin.

Currently, an industrial scale orthoalkylation of phenols is used which relates to the reaction of a vapor phase phenol with an alcohol in the presence of an acidic solid catalyst such as aluminum oxide. However, in this process, the alkylation site selectivity is insufficient. That is, not only are its ortho sites alkylated, so that a complicated method of separating and purifying the orthoalkylated reaction products is required.

Another industrial method of ortho-alkylating a phenol is based on the vapor phase reaction in the presence of a magnesium oxide catalyst. However, this catalyst has inherently low performance, and requires high temperatures of 75 ° C or higher, in practice 500 ° C or higher, in order to effect a sufficient reaction.

In addition, the life of the catalyst 15 is not long enough, so that regeneration after a relatively short period of time is required for practical application.

In order to overcome these difficulties, many types of catalysts have been proposed, especially those consisting mainly of manganese oxide. For example, in U.S. Pat. No. 3,971,832 is a catalyst consisting of, namely, of trimangane tetraoxide, in Japanese Patent No. III00 / 1,976, a manganese oxide catalyst to which magnesium oxide or selenium oxide has been added and in Japanese Patent Application Laid-Open No. 32 ^ 25 / 1979 described the addition of silicon dioxide.

A catalyst, which mainly contains manganese oxide, has excellent selectivity for ortho-alkylation and a high activity; however, the inventors propose a catalyst described in U.S. Pat. No. 30,1227,023 which contains a mixed oxide of manganese and silicon and one or more additives selected from alkaline earth metals to improve the physical strength of the catalyst, and a catalyst described in Japanese Patent Application Laid-open No. 76830/1980, which contains manganese oxide and with an alkali metal compound to prevent the deposition of oxygen-containing 8105099. i - 3 - hydrocarbon materials have been treated on the surface of the catalyst and to extend the life of the catalyst.

The catalysts have good properties for practical use, but they are insufficiently effective to utilize the alcohols effectively.

The present inventors have made extensive studies to overcome the aforementioned drawback of the aforementioned prior art process and have found that mixed metal oxide catalysts with one or more additives selected from group (a) , consisting of germanium oxide, tin oxide and lead oxide, are excellent for improving the effective utilization of alcohols.

The present invention relates to providing an improved method for the selective ortho-alkylation of a phenolic compound with at least one hydrogen atom in an ortho position by reacting the phenolic compound catalytically in the vapor phase with an alcohol.

Another aspect of the invention is to provide a catalyst suitable for carrying out the aforementioned selective ortho-alkylation, which catalyst not only has improved catalytic performance and excellent properties required for industrial catalysts, possesses, such as good moldability and high mechanical strength, but also excellent activity for improving effective utilization of alcohols.

These and other objects of the present invention will become more apparent from the following detailed description and examples.

According to the present invention there is provided a method of selectively ortho-alkylating a phenolic compound with at least one hydrogen atom in an ortho position by catalytically reacting the phenolic compound with an alcohol in the vapor phase, which is characterized by the fact that That the reaction is carried out in the presence of a catalyst containing manganese oxide and one or more additives selected from group (A), which group consists of germanium oxide, tin oxide and lead oxide. This catalyst may further contain one or more additives selected from the silica and group (B) consisting of alkali metal oxides and alkaline earth metal oxides.

The phenolic compound used in the invention is a compound containing a hydrogen atom in at least one of the ortho positions and can be represented by the formula indicated on the formula sheet, wherein, R 9, R 10 and R 20 independently, hydrogen atoms or aliphatic hydrocarbon groups such as the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl group proposals.

Specific examples of the phenolic compound are phenol, o-, m- and p-cresols, 2,3-, 2, U-, 2,5-, 3Λ- and 3,5-xylenols, trimethylphenols, tetramethylphenols, n- and isopropylphenols, n-, iso and tert-butylphenols and corresponding compounds. In addition, phenolic compounds with at least two different alkyl substituents on the same aromatic ring can also be used.

The alcohol used in the invention is a saturated aliphatic alcohol with 1-U carbon atoms. Examples of such alcohols are methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol and corresponding alcohols.

The catalyst used in the process according to the invention in any case contains manganese oxide and one or more additives, selected from group (A), consisting of germanium oxide, tin oxide and lead oxide. Such additives selected from group (A) are suitably present in an amount such that a metal atomic ratio of manganese oxide to such additives is between 100: 0.1 to 100: 50 and preferably from 100: 0.3 to 100: 30 is acquired.

If the catalyst also contains silicon dioxide, it is suitably present in such an amount that a ..... 35 atomic ratio of manganese to silicon ranging from 100: 0.1 to 8105099

«, V

- 5-100: 20 and preferably from 100: 0.05 to 100:10 is obtained.

In addition, if the catalyst contains one or more additives selected from group (B) consisting of alkali metal oxides and alkaline earth metal oxides, these additives are present in an amount such that an atomic ratio of manganese to alkaline earth metals varies from 100: 0.01 to 100:30 and preferably from 100: 0.05 to 100:20 and an atomic ratio of manganese -h to alkali metals ranging from 100: 10 to 100: 5 and preferably from 100: 10 to 100: 1 is obtained .

The role of an alkali metal oxide in the invention is primarily to provide moldability in order to obtain a practically applicable catalyst, in other words, to improve the moldability of the catalyst, while at the same time selectivity for obtaining ortho-geal -15 alkylated phenols based on phenols and alcohols are kept at a high value.

On the other hand, an alkali metal oxide is mainly used to suppress the decomposition of alcohols, which is undesirable for the intended reaction and to reduce the deposition of hydrocarbons produced by reaction of organic materials on the surface of the catalyst and extending the life of the catalyst.

As starting materials for various metal oxides used in this invention, one can use the derivatives of any metal, such as hydroxides, carbonates, salts of various mineral acids, salts of organic acids, in some cases sulfides, hydrides, etc. to apply.

A number of methods are available for preparing the catalyst. For example, the catalysts can be obtained by adding a small amount of water to a mixture of different compounds, as described above, and mixing the mixture well in a kneader or mixer, or by adding a suitable basic ingredient to a adding an aqueous solution of various starting materials, thereby obtaining the insoluble products precipitated together.

8105099 - 6 -

It is also possible to first form a mixture of some components and then add the remaining components by mixing or dripping. Usually, the resulting catalyst is dried at a temperature below 150 ° C and, if desired, suitable additives or auxiliary agents, such as polyvinyl alcohol, microcrystalline cellulose and similar materials, are added and the catalyst is used by an appropriate method such as extrusion, injection molding, vibration, rolling , etc., formed into any desired shape and then calcined, in order to prepare the catalyst for use.

In carrying out the process of the invention, a phenolic compound and an alcohol in a molar ratio ranging from 1: 1 to 1:15, preferably from 1: 1 to 1: 6, are mixed. Before adding the reaction components to the reaction zone, these starting materials can be diluted with a suitable inert gas, such as nitrogen or carbon dioxide, in order to allow the reaction to proceed smoothly. In addition, it is also effective to introduce a small amount of water with the reaction components into the reaction zone. The presence of this water serves not only to extend the life of the catalyst, but also to counteract any undesired decomposition of the alcohol.

The process according to the invention is carried out at a temperature from 300 ° C to 550 ° C, preferably from 350 ° C to 500 ° C. If the reaction temperature is higher, the selectivity for ortho-alkylation is reduced and the formation of various high-boiling products. On the other hand, if the reaction temperature is lower, the conversion of the reaction components will be insufficient for practical use, and as a result, large amounts of unreacted starting materials or intermediates must be recovered and recycled.

The reaction components are preferably added to the reaction zone at a liquid space velocity of 0.01 to 12 per hour. Generally, greater liquid space velocities became suitable for higher temperature reactions and used in reverse. The reaction can proceed under a pressure higher or lower than atmospheric pressure. The reaction can be carried out by any of the fixed bed, fluidized bed and moving bed methods.

Example I

500 g of manganese nitrate hexahydrate were heated to 1 ° C and diluted with water until a solution of 2500 ml was obtained. Ammonia was then added to form a precipitate. This precipitate of manganese hydroxide was sufficiently extracted. 10 washed with water, filtered and then dried at 130 ° C for 8 hours.

This dried filter cake and 3.2 g of white germanium dioxide powder were mixed well in a mixer, adding an appropriate amount of water, and dried again at 130 ° C for 8 hours. The mixture was then ground and formed in a known manner under pressure into cylindrical pellets with a diameter of k, 8 mm and a height of 3.2 mm, and then heated to 500 ° C, whereby a catalyst consisting of manganese oxide and germanium oxide was obtained. According to elemental analyzes, this catalyst 20 had a Mn: Ge atomic ratio of 100: 2.5.

100 g of this catalyst were packed in a stainless steel tubular reactor with an inner diameter of 21 mm.

The alkylation of phenol with methanol was performed according to the following method:

A mixture of phenol and methanol (in a 1: 5 molar ratio) was gasified by passing it through a carburetor, the temperature of which was set at 230 ° C and then 30 at a rate of 35 g per hour in a reactor the internal temperature of which was kept at U30 ° C.

The reaction products were analyzed by gas chromatography. The results are summarized in Table A. The percentage of methanol that had been used effectively is calculated according to the following formula: • 8105099 ______________________________________________________________________ "..........__._ t_.j8 ._-_____________________________

The percentage of methanol effectively used = o-cresol (mol) formed + 2,6-xylenol (mol) x 2 χ iqq reacted methanol (mol)

Example II

A catalyst consisting of manganese oxide and tin oxide was prepared in the same manner as described in Example I, except that the germanium dioxide was replaced with a white powder of tin oxalate (with an Mn: Sn atomic ratio of 100: U.9).

The alkylation of phenol with methanol was carried out in the same manner as described in Example I, except that the reaction temperature was now H15 ^ C. The results are shown in Table A.

Example III

A catalyst consisting of manganese oxide, tin oxide and calcium oxide was prepared as described in Example II, except that a white powder of calcium hydroxide with tin oxalate was added - (with a Mn: Sn: Ca atomic ratio of 100: 1, 8: 1,1). .

The alkylation of phenol with methanol was carried out in the same manner as described in Example I, except that the reaction temperature was changed to 10 ° C. The results are recorded in Table A. After the reaction was continued for about 350 hours, the catalyst pellets were removed from the tubular reactor, it was found that the shape of these pellets had not deteriorated.

Example IV

100 g of catalyst pellets prepared according to Example I were dipped in 0.01 N aqueous potassium hydroxide solution to give a potassium treated catalyst. This catalyst had a Mn: Ge: K atomic ratio of 100: 2.5: 0.002 according to elemental analyzes.

The alkylation of phenol with methanol was carried out under the same conditions as described in Example I.

The results obtained are shown in Table A.

8105099 - 9 -

% V

Example V

A catalyst treated with potassium was obtained in the manner described in Example IV using the catalyst pellets prepared according to Example III (with a Mn: Sn: Ca: K atomic ratio of 100: 8: 1.1: 0.003).

The alkylation of phenol with methanol was carried out under the same conditions as described in Example III.

The results obtained are shown in Table A.

Example VI

A catalyst consisting of manganese oxide and lead oxide was prepared in the same manner as described in Example I, except that the germanium dioxide was replaced with the blackish brown powder of lead dioxide (with an Mn: Pb atomic ratio of 100: 1.1).

The alkylation of phenol with methanol was performed in the same manner as described in Example I, except that the reaction temperature was now Ul8 ° C. The results obtained are shown in Table A.

Example VII

100 g of the catalyst prepared according to Example VI was dipped in a 0.01 N solution of cesium nitrate in water, whereby a cesium-treated catalyst was obtained. The catalyst had a Mn: Pb: Cs atomic ratio of 100: 1.1: 0.003 according to elemental analyzes.

The alkylation of phenol with methanol was carried out under the same conditions as described in Example VI.

The results obtained are shown in Table A.

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8105099 - 11 -

Comparative example 1

The dried precipitate of manganese hydroxide prepared according to Example I was compression molded into cyclindrical pellets with a diameter of 4.8 mm and a height of 3.2 mm, after which the pellets were heated to 500 ° C, whereby a catalyst containing only consisted of manganese oxide was obtained.

The alkylation of phenol with methanol was performed in the same manner as described in Example I, except that the reaction temperature was now 425 ° C. The results obtained are shown in Table B.

Table B

Phenols in products (mol%) The percentage of --- - - - - - - methanol 15 phenol o-cresol 2,6-xylenol 2,4,6-tri- which is used effectively methylphenol 0.9 6.5 92.0 0.5 60 1 hour after the start of the 20 reaction 2.9 15.0 81.5 0.4 55 20 hours "9.5 21.9 67.9 0.4 50 70 hours"

The shape of almost all catalyst pellets had deteriorated 100 hours after the start of the reaction.

Example VIII

1000 g of manganese nitrate hexahydrate were heated to 40 ° C. 21 g of water glass No. 3 were also diluted with 100 ml of water and then added dropwise to the aforementioned manganese solution. The resulting manganese nitrate solution was diluted with 5000 ml of water and ammonia was added thereto, whereby a precipitate of manganese oxide containing silicon dioxide was obtained. Then 10 g of germanium dioxide were added thereto. After mixing well, the mixture was washed with water, filtered and then dried at 180 ° C for 8 hours. The dried filter cake was ground and molded under pressure into cylindrical pressed pieces with a diameter of 18 mm and a height of 3.2 mm.

8105099 _______________________________________________________________________- 1_2__r______________________________________

After the pellets were heated to 500 ° C., A stainless steel tubular reactor with an internal diameter of 21 mm was packed with 100 g of these pellets.

The alkylation of phenol with methanol was performed in the following manner:

A mixture of phenol and methanol (in a molar ratio of 1: 5) was converted into the gaseous form by passing this mixture through a carburettor at a set temperature of 230 ° C and then at the rate of bo g per hour in the reactor, the internal temperature of which was kept at 25 ° C.

The reaction products obtained were analyzed by gas chromatography. The results obtained are shown in Table C.

Example IX

A catalyst consisting of manganese oxide, silicon oxide and tin oxide was prepared in the same manner as described in Example VIII, except that the germanium dioxide was replaced with tin oxalate (with an Mn: Si: Sn atomic ratio of 100: 2.9: 5, 0).

The reaction was conducted in the same manner as described in Example VIII.

The results obtained are shown in Table C.

Example X.

A catalyst consisting of manganese oxide, silicon oxide, tin oxide and calcium oxide was prepared as described in Example IX, except that additionally addition of calcium hydroxide with tin oxalate (with an Mn: Si: Sn: Ca atomic ratio of 100: 2.9: 5.0: 1.0).

30. The reaction was carried out in the same manner as described in Example VIII.

The results obtained are recorded in Table C. After the reaction was continued for 1 hour and a half hours, the catalyst pellets were taken from the tubular reactor, revealing that no pellets, the shape of which was in reverse, were present. 0 9 9 - 13 - gone.

Example XI

100 g of the catalyst pellets prepared according to Example VIII were dipped in 0.01 µl of potassium hydroxide solution in water to obtain a catalyst treated with potassium (with an Mn: Si: Ge: Ca atomic ratio of 100: 2.9: 2.7: 0.003) was obtained.

The reaction was carried out in the same manner as described in Example VIII. The results obtained are included in Table C.

Example XII

A catalyst treated with potassium was obtained as described in Example XI using the catalyst pellets prepared according to Example X (with an Mn: Si: Sn; Ca: K atomic ratio of 100: 2.9 - 38) : 1.1: 0.003).

The reaction was carried out under the same conditions as described in Example VIII. The results obtained are shown in Table C.

Example XIII

A catalyst consisting of manganese oxide, silicon oxide and lead oxide was obtained in the same manner as described in Example VIII, except that the germanium dioxide was replaced by lead dioxide (with an Mn: Si: Pb atomic ratio of 100: 2.9: 1, U) .

The reaction was carried out under the same conditions as described in Example VIII. The results obtained are shown in Table C.

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8105099 o - 15 -

Comparative example 2

A catalyst "consisting of manganese oxide and silicon oxide was prepared in the same manner as described in Example VIII, except that no germanium oxide was used. The reaction was carried out in the same manner as described in Example VIII, except that the reaction temperature was changed to 1 (- 30 ° C. The results obtained are shown in Table D.

Table D

Phenols in the products (mol%) The percent phenol o-cresol 2,6-xylenol 2,1,6-tn-effective methylphenol ,,, ...

__ _ is used__ 15 0.5 3.0 9 ^, 3 1.5 53 10 hours after the start of the reaction 1.0 5.1 91.5 1, fc 50 100 hours "20 2.5 11.0 85 1.1 k9 200 hours "300 16 * and after the start of the reaction about 10-20% of the catalyst pellets had deteriorated.

8105099

Claims (12)

1. Process for selectively ortho-alkylating a phenolic compound with at least one hydrogen atom in an ortho position by reacting the phenolic compound in the vapor phase catalytically with an alcohol, characterized in that the reaction is in the presence of a catalyst containing manganese oxide and one or more additives selected from group (A) consisting of germanium oxide, tin oxide and lead oxide. 2. Process according to claim 1, characterized in that the catalyst additionally contains silicon oxide. Process according to claim 1 or 2, characterized in that the catalyst additionally contains one or more additives selected from group (B), consisting of alkali metal oxides and alkaline earth metal oxides. U. A process according to any one of the preceding claims, characterized in that the one or more additives selected from group (A) are present in an amount such that they have an atomic ratio of manganese to these additives ranging from 100: 0, Give 1 to 100: 50. A process according to claim 2-h, characterized in that the silicon oxide is present in such an amount that an atomic ratio of manganese to silica ranging from 100: 0.01 to 100:20 is obtained. 6. Process according to claims 3-5, characterized in that the one or more additives selected from group (B) are present in such an amount that an atomic ratio of manganese to alkaline earth metals, ranging from 100: 0.01 to 100:30 and an atomic ratio of manganese to alkali metal oxides ranging from 100:10 to 100: 5 is obtained. Process according to any one of the preceding claims, characterized in that the reaction is carried out at a temperature between 300 and 550 ° C. 8. Process according to any one of the preceding claims, characterized in that the phenolic compound and the alcohol are added to the reaction zone in a molar ratio ranging from 8105099-17 - from 1: 1 to 1:15. 9. Process according to any one of the preceding claims, characterized in that the phenolic compound and the alcohol are added to the reaction zone at a liquid space velocity of 0.01 to 12 per hour. 10. Process according to any one of the preceding claims, characterized in that phenol and / or o-cresol are used as phenolic compound with at least one hydrogen atom in an ortho position. Process according to any one of the preceding claims, characterized in that the alcohol used is a low, saturated alkali alcohol with 1-U carbon atoms. 12. Process according to claim 11, characterized in that the alcohol used is methyl alcohol. 13. Method as described in the description and / or examples. * r 8105099