JPH061740A - Method for producing orthoalkylphenol - Google Patents

Abstract

PURPOSE:To obtain the ortho alkylphenol in a high selectivity and in a high conversion over a long time by reacting a phenolic compound with an alcohol in the presence of a manganese oxide which is prepared by a specific method and which has an excellent catalytic strength. CONSTITUTION:A phenolic compound having a hydrogen atom at the ortho position is reacted with a lower alcohol in a molar ratio of 1:1 to 1:10, preferably 1:3 to 1:7, in the presence of a catalyst at 300-500 deg.C to obtain the ortho alkylphenol. The catalyst is prepared by calcining manganese oxide catalyst in the presence of carbon in an amount of 0.1-10wt.%, preferably 0.1-5wt.%, based on the manganese oxide catalyst at 1000-1500 deg.C, preferably 1000-1400 deg.C, for 1-30hrs.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing orthoalkylphenols from phenols and alcohols. Orthoalkylphenols such as orthocresol and 2,6-xylenol are useful compounds as antioxidants, disinfectants and preservatives, and as raw materials for agricultural chemicals, pharmaceuticals, phenolic resins, plasticizers and the like.

[0002]

2. Description of the Related Art A method for producing an ortho-methylated phenol by subjecting phenol and methanol to a gas phase catalytic reaction in the presence of a metal oxide catalyst is known and is industrially practiced. Aluminum oxide, magnesium oxide, manganese oxide, iron oxide, chromium oxide, zinc oxide and the like can be used as the metal oxide catalyst. However, although magnesium oxide has a high ortho-selectivity, its activity is low, and the catalyst life becomes short when the reaction is carried out at a high temperature. Also,
Although aluminum oxide has high activity, it has low selectivity and many by-products. Iron oxide has a high activity, but has a low selectivity and a large decrease in activity, so that the catalyst life is short.

On the other hand, manganese-based catalysts have high activity and high selectivity, and various proposals have been made. (Japanese Patent Publication Sho 51-11
101, JP-A-54-32425 and JP-A-54-812.
No. 31, No. 55-30494, No. 55-76830
No. 57-53422, No. 57-81425-7.
No. 57-85332, No. 60-34923, No. 60-218345, etc.). However, the mechanical strength of the catalyst was insufficient, and the powder was pulverized by the reaction or regeneration operation, and the reaction system was sometimes clogged. As a catalyst having excellent crushing strength, JP-A-57-81425 discloses a selective alkylation method using a mixed catalyst of manganese oxide, silicon oxide, an alkali metal, etc., and aluminum oxide of a specific crystal type. Have been described. Also, JP-A-57-9
Japanese Patent No. 4247 describes an internal catalyst in which a catalyst is covered with an outer shell and voids are formed between the catalyst and the outer shell, as a solution to the drawback caused by pulverization of the catalyst.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a method of producing an orthoalkylphenol with a catalyst having an excellent catalyst strength for a long time with a high selectivity and a high conversion rate in a method using a manganese oxide catalyst. Is to provide.

[0005]

The present invention relates to a method for producing an orthoalkylphenol by reacting a phenol having a hydrogen atom at the ortho position with a lower alcohol in the presence of a manganese oxide catalyst, and using manganese as a catalyst. Oxide catalyst in the presence of carbon 1000 ~ 1500 ℃
A method for producing an orthoalkylphenol characterized by using a catalyst obtained by calcination in. The phenols used in the present invention are phenol compounds having one or two hydrogen atoms in the ortho position and are represented by the following general formula.

[0006]

[Chemical 1]

(In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, or an aromatic carbon atom which may have a substituent. Examples of such compounds include phenol, cresols, xylenols, trimethylphenols,
Examples thereof include ethylphenols, butylphenols, phenylphenols, naphthylphenols and hydroquinone. As the lower alcohol, methanol,
Ethanol, n-propanol, i-propanol, n
-Butanol, i-butanol, t-butanol, pentanol, hexanol and the like.

The manganese oxide catalyst used in the method of the present invention is a catalyst containing manganese oxide. Specific examples of the catalyst include manganese oxides such as manganese monoxide, manganese trioxide, manganese dioxide, and trimanganese tetraoxide. Furthermore, these catalysts include carriers such as alumina and silica, water glass, boric acid, phosphoric acid,
A binder such as a clay-based component, activated carbon, etc. may be included.

In the present invention, a catalyst obtained by firing the above manganese oxide catalyst in the presence of carbon is used. The carbon used in the present invention may be any carbon as long as it is present in the catalyst system when the catalyst is calcined at 1000 ° C. or higher. Examples of the firing method using carbon include the following methods. Firing is performed using carbon having a combustion starting temperature of about 1000 ° C. or higher. The carbon whose combustion starting temperature is 1000 ° C or less,
The temperature is raised to 1000 ° C. and fired under conditions that do not cause combustion. Carbon is produced in situ by steaming and burning the organic matter at a low temperature, and the temperature is raised to 1000 ° C. and fired under conditions that do not cause the combustion.

The combustion start temperature of carbon differs depending on the graphite content, the surface area of the carbon particles, and the like. The amount of carbon to be present in the catalyst during the catalyst calcination is 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the manganese oxide catalyst. When the amount of carbon is small, the strength of the catalyst obtained after firing is low, and when the amount of carbon is too large, the carbon remains in the catalyst to lower the strength, and a large amount of gas is generated during carbon combustion. Does not develop sufficient strength.

The catalyst is calcined at a temperature of 1000 to 1500 ° C, preferably 1000 to 1400 ° C. The firing time is about 1 to 30 hours, depending on the firing temperature. A higher firing temperature requires a shorter time, and a lower firing temperature requires a longer time. By this calcination, the manganese oxide on the surface of the catalyst particles is reduced and turned into manganese to cover the surface, whereby a catalyst having excellent catalyst strength is obtained.

The orthoalkylphenol is produced by reacting a phenol and a lower alcohol in the presence of the above catalyst at a temperature of 300 to 500 ° C. The molar ratio of phenol to lower alcohol is in the range of 1: 1 to 1:10, preferably 1: 3 to 1: 7. The feed rate of the raw material is 0.1 to 0.1 in terms of liquid hourly space velocity.
It is preferably about 5 hr ⁻¹ , and generally, it is preferable that the liquid hourly space velocity is high at a high reaction temperature and is low at the low reaction temperature side.

It is also possible to allow water to coexist in the reaction system. At this time, the molar ratio of water to phenols is preferably up to about 5 times. The reaction pressure is reduced pressure,
It can be either normal pressure or pressurization, but usually 1-10 kg
It is about / cm ² G. The reaction can be carried out in a liquid phase or a gas phase, but the reaction is easier in the gas phase from the viewpoint of reaction pressure.
The type of reaction can be fixed bed, fluidized bed, or moving bed. The catalyst used in the reaction can be regenerated by appropriately contacting it with an oxygen-containing gas at 300 to 700 ° C. After removing the gas components, the reaction product is separated and recovered by a conventional method. When a substance having a relatively low boiling point is the target component, it is separated by distillation to collect a low fraction. Further, when a substance having a high boiling point is the target component, means such as crystallization is effective.

[0014]

According to the method of the present invention, orthoalkylphenols can be produced for a long period of time with high selectivity and high conversion.

[0015]

The present invention will be described in more detail with reference to the following examples. Example 1 (Preparation of catalyst) Manganese oxide 1 obtained by heating electrolytic manganese dioxide having an average particle size of 50 μm at 1000 ° C.
100 parts of graphite (manufactured by Light Carbon Co., Ltd.), 5 parts of Avicel (manufactured by Asahi Kasei Co., Ltd.) and a small amount of water were mixed and kneaded, and the mixture was put into a rotary disk type rolling granulator and sprayed with water. While sprinkling, it was made into a granular material of about 1 mm. In this granular material,
While spraying water in the form of spray, the kneaded material was also sprinkled at the same time to form a spherical object having a diameter of 4.5 mm in a snowball manner.
After drying this granular material at 80 to 120 ° C., it is placed in a stirrer and gradually heated in a firing furnace, and heated to a particularly gentle temperature rise from 250 ° C. to 600 ° C., and then to 1250 ° C. , Hold at this temperature for 3 hours, the particle size is 4.5
A catalyst consisting of mm manganese oxide was obtained.

(Alkylation Reaction) Catalyst 6 Obtained Above
6 ml was filled in a reaction tube made of SUS-304, reaction temperature: 390 ° C., reaction pressure: 2 kg / cm ² , LHSV: 0.
The reaction was carried out by supplying a mixture of methanol: phenol: water (molar ratio) = 6: 1: 0.5 under the condition of 5 hr ⁻¹ . After 20 hours, the phenol conversion was 94% and the phenol selectivity was 98%. The breaking strength of the catalyst after this reaction was 5.2 kg / cm ² , and the strength was hardly reduced. Further, the reaction was further continued while raising the reaction temperature so that the molar ratio of the 2,6-xylenol and o-cresol produced was kept at 2. After 200 hours, the phenol selectivity was 98%. The fracture strength of the catalyst after this reaction is 5.2.
It was kg / cm ² , and the strength was hardly reduced.

This catalyst was regenerated with a mixed gas of air / nitrogen = 1/20 at 500 ° C., and similarly reacted for 200 hours. After repeating this reaction / regeneration operation 5 times, the reaction was carried out for 20 hours under the above reaction conditions. As a result, the phenol conversion was 94% and the phenol selectivity was 96%. This catalyst was taken out from the reaction tube, held in a firing furnace at 1250 ° C. for 3 hours, and re-fired. When this catalyst was used to carry out the reaction again under the above conditions, the phenol conversion rate at 20 hours was 94%, and the phenol selectivity was 98%, and the initial performance was recovered. The breaking strength of this catalyst was 5.2 kg / cm ² , and the strength was hardly reduced.

Comparative Example 1 (Preparation of catalyst) A catalyst was produced in the same manner as in Example 1 without adding graphite. (Alkylation reaction) Using the catalyst obtained above, a reaction was carried out under the same conditions as in Example 1. After 20 hours, the phenol conversion was 94% and the phenol selectivity was 98%. The breaking strength of the catalyst after this reaction was 0.2 kg / cm ² , and the strength was remarkably reduced. Furthermore, generate 2,6
The reaction was further continued while increasing the reaction temperature so that the molar ratio of -xylenol and o-cresol was kept at 2. 20
After 0 hour, the phenol selectivity was 98%. The breaking strength of the catalyst after this reaction was 0.1 kg / cm ² , and the strength was further lowered. This catalyst was regenerated with a mixed gas of air / nitrogen = 1/20 at 500 ° C. and similarly reacted for 200 hours. After repeating this reaction / regeneration operation 5 times,
When the reaction was carried out for 20 hours under the above reaction conditions, the phenol conversion was 94% and the phenol selectivity was 96%.
When this catalyst was extracted from the reaction tube, it was pulverized.

Example 2 (Preparation of catalyst) Manganese oxide 1 obtained by heating electrolytic manganese dioxide having an average particle size of 50 μm at 1000 ° C.
1 part of 50 parts of walnut powder and 50 parts of wheat flour mixed with 5 parts of Avicel (manufactured by Asahi Kasei Co., Ltd.) and a small amount of water were mixed and kneaded, and then put into a rotary disk type rolling granulator. ,
While spraying water in the form of spray, it was made into granules of about 1 mm. While spraying water in the form of spray onto the granules, at the same time, sprinkling the kneaded material onto the granules, the diameter of which is 4.5 m in a snowball manner.
It was a spherical object of m. After drying the granules at 80 to 120 ° C., the granules are placed in a stirrer and placed in a firing furnace in a gas phase to have an oxygen concentration of 3
%, Gradually heating from 250 ° C. to 600 ° C. so that the temperature rises to 1250 ° C. and holding at this temperature for 3 hours. A catalyst was obtained.

(Alkylation Reaction) Catalyst 6 Obtained Above
Example 1 was filled with 6 ml of a reaction tube made of SUS-304.
The reaction was performed in the same manner as in. After 20 hours, the phenol conversion was 94% and the phenol selectivity was 98%. The breaking strength of the catalyst after this reaction was 3.1 kg / cm ² . Furthermore,
The reaction was further continued while increasing the reaction temperature so that the molar ratio of the 2,6-xylenol and o-cresol produced was kept at 2. After 200 hours, the phenol selectivity was 98%. The breaking strength of the catalyst after this reaction was 3.0 kg / cm ² , and the strength was hardly reduced. This catalyst is air /
Regeneration was carried out at 500 ° C. with a mixed gas of nitrogen = 1/20, and the reaction was carried out in the same manner for 200 hours. After repeating this reaction / regeneration operation 5 times, the reaction was carried out for 20 hours under the above reaction conditions. As a result, the phenol conversion was 94% and the phenol selectivity was 96%. When this catalyst was taken out from the reaction tube and the breaking strength was measured, it was 3.0 kg / cm ² , and the strength was hardly reduced.

Comparative Example 2 (Preparation of catalyst) Manganese oxide 1 obtained by heating electrolytic manganese dioxide having an average particle diameter of 50 μm at 1000 ° C.
1 part of 50 parts of walnut powder and 50 parts of wheat flour mixed with 5 parts of Avicel (manufactured by Asahi Kasei Co., Ltd.) and a small amount of water were mixed and kneaded, and then put into a rotary disk type rolling granulator. ,
While spraying water in the form of spray, it was made into granules of about 1 mm. While spraying water in the form of spray onto the granules, at the same time, sprinkling the kneaded material onto the granules, the diameter of which is 4.5 m in a snowball manner.
It was a spherical object of m. After drying the granules at 80 to 120 ° C., the granules are placed in a stirrer and gradually heated in a baking furnace to
From 0 ° C to 600 ° C, control the oxygen concentration to about 2% and heat it so that the temperature rises particularly slowly.
The temperature was raised to 0 ° C., and the temperature was maintained for 3 hours for calcination to obtain a catalyst composed of manganese oxide having a particle diameter of 4.5 mm.

(Alkylation Reaction) Catalyst 6 Obtained Above
Example 1 was filled with 6 ml of a reaction tube made of SUS-304.
The reaction was performed in the same manner as in. The phenol conversion rate after 20 hours was 94%, but the phenol selectivity at that time was 98%.
%Met. The breaking strength of this catalyst was 0.1 kg / cm ² . Further, the reaction was further continued while raising the reaction temperature so that the molar ratio of the formed 2,6-xylenol and o-cresol was kept at 2. After 200 hours, phenol selectivity 9
It was 8%. The breaking strength of this catalyst was 0.0 kg / cm ² , and there was almost no strength.

Claims (1)

[Claims] 1. A method for producing an orthoalkylphenol by reacting a phenol having a hydrogen atom at the ortho position with a lower alcohol in the presence of a manganese oxide catalyst, wherein the manganese oxide catalyst is used in the presence of carbon. A method for producing orthoalkylphenol, which comprises using a catalyst obtained by calcination at a temperature of 1000 to 1500 ° C.