JPH0625041A - Method for producing orthoalkylphenol - Google Patents

Abstract

PURPOSE:To obtain an o-alkylphenol in high selectivity and convertibility under a stabilized operation for a long time using a manganese oxide catalyst prepared by a specific means. CONSTITUTION:Firstly, a manganese oxide catalyst is baked in an atmosphere containing 0.1-20 (pref. 1-10)vol.% of a reducing gas (pref. hydrogen, carbon monoxide, or mixture thereof) at 1000-1500 (pref. 1100-1400) deg.C. Then, in the presence of the resultant catalyst, reaction is made between (A) a phenolic compound bearing hydrogen atom at o-site and (B) a lower alcohol at the molar ratio A/B of (1:3) to (1:7) at 300-500 deg.C at a liquid space velocity of 0.1-5hr<-1>, thus obtaining the objective o-alkylphenol.

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.

JP-A-55-143921 discloses a method of using a manganese oxide-containing catalyst after pretreatment with a reducing gas. In this method, 100-80
It is treated at a relatively low temperature of 0 ° C., which is believed to be present on the catalyst surface when calcined in normal air or under an atmosphere such as nitrogen as described in the publication. This is because the purpose is to remove highly reactive oxygen species.

[0005]

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.

[0006]

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. Is used for the reaction after firing at a temperature of 1000 to 1500 ° C. in an atmosphere in which a reducing gas of 0.1 to 20% by volume exists, and a method for producing an orthoalkylphenol. The phenols used in the present invention are
It is a phenol compound having one or two hydrogen atoms in the ortho position and is represented by the following general formula.

[0007]

[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. Specific examples of such a compound include phenol, cresols, xylenols, trimethylphenols, ethylphenols, butylphenols, phenylphenols, naphthylphenols and hydroquinone. As the lower alcohol, methanol, ethanol, n-propanol, i-
Propanol, n-butanol, i-butanol, t-
Examples thereof include 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 method of the present invention, the above manganese oxide catalyst is added in the presence of a reducing gas at 1000 to 1500 ° C.
It is used after firing at the temperature. The presence of the reducing gas means an atmosphere in which the reducing gas exists. Examples of the reducing gas include hydrogen, carbon monoxide, ammonia, methanol, ethanol, methane, ethane, propane, butane and the like, or a mixture thereof. Among these, hydrogen, carbon monoxide, and a mixture thereof are preferable because the firing temperature is high. These reducing gases may be diluted with carbon dioxide, nitrogen, steam or the like, or may be used.
Oxygen may coexist. In some cases it may be preferable for oxygen to be present. The concentration of the reducing gas is 0.1 to
It is about 20% by volume, preferably 1 to 10% by volume. When it is less than 0.1% by volume, the catalyst strength after the reaction is lowered, and when it exceeds 20% by volume, the reaction activity is lowered.

The catalyst is calcined at 1000 to 1500 ° C, preferably 1100 to 1400 ° C. The firing time varies depending on the firing temperature, but is usually about 1 to 30 hours. Higher calcination temperatures require shorter times, and lower calcination temperatures require longer times.

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.
5 parts of Avicel (manufactured by Asahi Kasei Co., Ltd.) and a small amount of water were added to 00 parts and kneaded. . While sprinkling 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 in a snowball manner.
It was a spherical object of mm. After drying this spherical substance at 80 to 120 ° C., it is put in a stirrer and gradually heated in a baking furnace,
It is heated to a particularly gentle temperature rise from 50 ° C to 600 ° C and is raised to 1250 ° C, at which temperature carbon monoxide 4%, hydrogen 3%, carbon dioxide 4%, oxygen 1%, and the balance nitrogen. The mixture was kept in an atmosphere of water vapor for 3 hours to obtain a catalyst of manganese oxide having a particle diameter of 4.5 mm.

(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 5.0 kg / cm ² . 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 breaking strength of the catalyst after this reaction was 5.0 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%. . The breaking strength of the catalyst at this time was 4.8 kg / cm ² , and the strength was hardly reduced.

Comparative Example 1 (Preparation of catalyst) A spherical material granulated in the same manner as in Example 1 was dried at 80 to 120 ° C., placed in a stirrer and gradually heated in a gas firing furnace to 250 ° C. To 600 ° C., the temperature is raised to 1250 ° C., and at this temperature, an atmosphere consisting of carbon dioxide 4%, oxygen 10% and the balance nitrogen and water vapor is maintained for 3 hours, A catalyst made of manganese oxide having a particle diameter of 4.5 mm 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 0.2 kg / cm ² , and the strength was extremely low. 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 breaking strength of the catalyst after this reaction was 0.1 kg / cm ² , and the strength was extremely low. This catalyst was mixed with air / nitrogen = 1/20 at 500 ° C.
It was regenerated in the same manner and reacted in the same manner for 200 hours. This reaction / regeneration operation was repeated 5 times, and then 20 times under the above reaction conditions.
After reacting for a time, the phenol conversion was 94% and the phenol selectivity was 96%. The breaking strength of the catalyst at this time was 0 kg / cm ² , and the strength could hardly be measured.

Comparative Example 2 (Preparation of catalyst) A spherical material granulated in the same manner as in Example 1 was dried at 80 to 120 ° C., placed in a stirrer and gradually heated in a gas firing furnace to 250 ° C. To 600 ° C, the temperature rises to 900 ° C, and at this temperature, carbon monoxide 4%, hydrogen 3%, carbon dioxide 4%, oxygen 1%, the rest is nitrogen and water vapor. It was kept in an atmosphere consisting of 3 hours for 3 hours 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 the catalyst at this time could not be measured.

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 an amount of 0.1 to 20 volumes. % To 1000 to 1500 in an atmosphere in which a reducing gas is present.
A method for producing an orthoalkylphenol, which comprises using it in a reaction after firing at a temperature of ° C.