JPH06298687A - Continuous production of ortho-alkylated phenolic compound - Google Patents

Abstract

PURPOSE:To provide a process for the continuous production of an ortho- alkylated phenolic compound capable of suppressing the formation of impurity by-products, increasing the orthoselectivity and keeping the high selectivity over a long period. CONSTITUTION:An ortho-alkylated phenolic compound is produced by contacting a phenolic compound with an alcohol in vapor phase in the presence of a supported catalyst containing an iron oxide using a fluidized bed reactor, thereby alkylating the phenolic compound. In the above process, the selectivity of the phenolic compound is improved and the ortho-alkylated phenolic compound is continuously produced in high efficiency by using a reactor and a regeneration apparatus, extracting a prescribed amount of the catalyst from the reactor at prescribed time interval and returning a prescribed amount of the catalyst from the regeneration apparatus to the concentrated catalyst phase of the reactor.

Description

Detailed Description of the Invention

[0001]

The present invention relates to phenols and alcohols in the presence of a supported catalyst containing an iron oxide,
The present invention relates to a method for efficiently producing an ortho-alkylated phenol compound continuously by contacting it in a gas phase using a fluidized bed reactor.

The ortho-alkylated phenol compounds produced by the method of the present invention are important as industrial raw materials. For example, orthocresol is a raw material for agricultural drugs, epoxy resins and the like, and 2,6-xylenol is a polyphenylene oxide. The raw material, 2,3,6-trimethylphenol, is useful as a raw material for vitamin E.

[0003]

2. Description of the Related Art Heretofore, as a method for producing an ortho-alkylated phenol, a method relating to a catalyst system to be used has been the main, and a method mainly containing iron, vanadium, manganese, magnesium and the like is known. Regarding improvement of activity and ortho position selectivity, Japanese Patent Publication No. 47-37943
This can be largely improved by using a catalyst containing vanadium oxide and iron oxide as described in Japanese Patent Laid-Open Publication No. 2003-242242.

However, even if this catalyst is used, the selectivity of phenols is low in the early and late stages of the reaction, which is not satisfactory for industrially more efficient production. It was necessary to increase the selectivity.

A method for continuously producing an ortho-alkylated phenol compound is disclosed in JP-A-56-49.
As described in Japanese Patent No. 331,331, a reaction device composed of a reaction part and a catalyst regeneration part, or a reaction device composed of two or more series, performs reaction and catalyst regeneration in parallel and is regenerated. Disclosed is a method of using different catalysts in the reaction in a circulating or alternating manner. Further, the drawing shown on the last page of JP-A-56-49331 is shown in FIG. 1. Here, the regenerated catalyst is placed in the upper part of the reactor, that is, in the fluidized bed reactor, the catalyst-lean phase portion is used. Have been shown to be added to.

[0006] However, the purpose of this continuous production method is to obtain stable product quality without changing the separation and purification steps following the reaction as described in the official gazette, and to enhance the selectivity of phenols, Moreover, there is no idea or disclosure of maintaining the high selectivity for a long time. For industrial production, it is natural to carry out stable production with stable quality, and it is desired to obtain even higher selectivity and maintain high selectivity for a long period of time. .

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to continuous production of ortho-alkylated phenol capable of suppressing the by-product of impurities, enhancing the ortho-selectivity, and maintaining the high selectivity for a long period of time. It is intended to provide a method.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to develop a method for producing an ortho-alkylated phenol having suppressed ortho-position selectivity by suppressing the by-product of impurities. In the presence of a supported catalyst containing iron oxide,
When carrying out a gas phase catalytic reaction using a fluidized reactor, it was found that it is desirable to extract the catalyst in the middle and add the regenerated catalyst to the concentrated phase portion of the reactor, and completed the present invention.

In the method of the present invention, when a phenol and an alcohol are contacted with each other in a gas phase in a gas phase using a fluidized bed reactor for alkylation, a supported catalyst containing an iron oxide is withdrawn in the middle of the concentrated phase portion. The method for continuous production of an ortho-alkylated phenol compound is characterized in that

The catalyst composition is vanadium in addition to iron,
It may contain chromium or an alkali metal. When vanadium is contained in addition to iron, vanadium and iron of the catalyst have various valence oxides, but any valence oxide may be used. In the case of vanadium, for example, V ₂ O
₅ , V ₂ O ₄ , V ₂ O ₃ and VO are preferable, and in the case of iron, Fe ₂ O ₃ , Fe ₃ O ₄ and FeO are preferable.

The catalyst can be made by various preparation methods.
As vanadium source, its oxide, ammonium salt,
Chlorides, oxychlorides, etc., and iron sources such as oxides, nitrates, chlorides, sulfates, oxalates, etc.
It can be prepared by any method such as a mixing method, an impregnation method and a precipitation method.

The catalyst is alumina, silica, silica.
Use with a suitable carrier such as alumina or diatomaceous earth. However, the carrier does not necessarily have to be used.

The raw material phenols to which the method of the present invention is applied include phenol, orthocresol, metacresol, paracresol, xylenols other than 2,6-xylenol, orthoethylphenol, orthopropylphenol, orthotert-butylphenol and the like. However, examples of the raw material alcohols include methanol, ethanol, n-propanol and the like, and examples of the ortho-position alkylated phenol obtained by the reaction include orthocresol, 2,6-xylenol, 2,4-xylenol, 2,3. , 5-Trimethylphenol, 2,3,6-
There are trimethylphenol, 2,4,6-trimethylphenol and the like.

The present invention will be described in detail below.

According to the research conducted by the present inventors, on a supported catalyst containing an oxide of iron, an activity deterioration curve of an ortho-positioned alkylation main reaction and an impurity formation side reaction in the above reaction,
That is, the decrease with time of the reaction rate constant is expressed as shown in FIG.

Therefore, the change with time in the phenol selectivity shown by the following mathematical formula 1 is expressed as shown in FIG.

[0017]

[Equation 1] That is, on the basis of a constant production amount, when the alkylation reaction was carried out with a constant catalyst amount as shown in FIGS. 2 and 3, the phenol selectivity was low at the point A at the initial stage of the reaction, and the reaction in which the activity of the catalyst was slightly deteriorated At the midpoint B point, the phenols selectivity becomes maximum, and at the latter point C of the reaction where the catalyst activity deterioration has progressed, the phenols selectivity becomes low.

From this fact, the present inventors have found that in order to always maintain the phenol selectivity at a high level on the basis of a constant production amount, the catalyst deterioration state after the start of the reaction is the state of point B in FIGS. 2 and 3. It is important to maintain the state of point B by adding the regenerated catalyst to the catalyst rich phase portion of the reaction device, while removing the deteriorated catalyst as the deterioration progresses, and It was found that by separately providing a reactor and a regenerator, it is possible to continuously produce an ortho-alkylated phenol compound while maintaining the phenols selectivity at a high level as shown in FIG. The present invention has been developed.

Specifically, to maintain the state of the catalyst at the point B, the cumulative alkylation amount represented by the following mathematical formula 2 is set to 0.
4-0.8 (kmol ortho-position alkylation / kg catalyst)
It is achieved by keeping at. Preferably, the cumulative alkylation amount is 0.5 to 0.7 (ortho-position alkylation kmol /
It is recommended to use kg of catalyst.

[0020]

[Equation 2] That is, by keeping the cumulative amount of alkylation substantially constant, it is possible to continuously produce the ortho-alkylated phenol compound while maintaining the deteriorated state of the catalyst near point B where the phenol selectivity is highest.

The catalyst withdrawal and addition methods may be continuous or batch, and the phenol selectivity can be increased. However, in either method, in order to keep the amount of catalyst in the reactor constant, it is preferable that the amount of extraction and the amount of addition are the same. The amount of withdrawal and addition can be determined by determining the integrated amount of alkylation to be maintained and the amount of catalyst in the reactor.

The catalyst-rich phase portion refers to a portion having a high catalyst density in the reactor, and for example, in a fluidized bed reactor, it is a portion which is approximately 1/2 or less of the height of the reactor, and a catalyst is added thereto. Preferably.

Needless to say, it is preferable that the catalyst is extracted and the addition is started in the vicinity of the point B which gives the highest phenol selectivity in FIG.

The reaction temperature is in the range of 250 to 550 ° C, preferably 300 to 400 ° C. When the temperature is 250 ° C. or lower, the reaction rate of phenols is low, and when the temperature is 550 ° C. or higher, a large amount of compounds alkylated at positions other than the ortho positions are by-produced, and useless decomposition of alcohols often occurs.

The reaction pressure may be normal pressure, reduced pressure, or increased pressure. The contact time between the gas and the catalyst is preferably 0.5 to 50 seconds, more preferably 1 to 20 seconds.

In the method of the present invention, gases such as steam, nitrogen, hydrogen, carbon monoxide, carbon dioxide and methane may coexist in addition to the raw materials of phenols and alcohols.

[0027]

The present invention will be described in more detail with reference to the following examples.

The phenol selectivity in the examples is defined by the following mathematical formula 3.

[0029]

[Equation 3] The cumulative methylation amount is defined by the following mathematical formula 4.

[0030]

[Equation 4] Example 1 Phenol and methanol were subjected to a gas phase catalytic reaction in a fluidized bed reactor using a catalyst in which iron oxide and vanadium oxide were supported on silica. As a catalyst, ammonium metavanadate (NH ₄ VO ₃ ) was dissolved in pure water heated to 90 ° C., and ferric nitrate (Fe (N
_{O 3) 3 · 9H 2 O} ) and added silica sol (manufactured by Nissan Chemical Snowtex N) containing 30 wt% of SiO _2. A slurry of finely divided suspension material uniformly dispersed in silica sol colloid is obtained. This was dried with a co-current type spray dryer.

The atomization of the raw material slurry can be carried out by any of the industrially used centrifugal system, two-fluid nozzle system or high-pressure nozzle system, but the centrifugal system is particularly preferred. In the centrifugal system, the particle size is adjusted to 10 to 15 which is suitable for use in a fluidized bed reactor by controlling the disk rotation speed and the slurry supply speed.
It can be distributed between 0 μm.

The obtained dry powder was pre-baked at 350 ° C. for 2 hours using a tunnel kiln and then at 700 ° C. for 5 hours.
Time firing was performed.

Using 2.5 kg of this catalyst, a diameter of 10 c
The methylation reaction of phenol was started in a fluidized bed reactor of m. At this time, the feed amount of phenol per hour per unit catalyst weight of 1 kg was adjusted to be 0.075 kg.

The raw material molar ratio is phenol: methanol:
A liquid with water of 1: 5: 3 was used.

The reaction was carried out continuously for 40 days, and once the accumulated methylation amount reached 0.6 (kmol of ortho-position methylation / kg of catalyst) on the 20th day, the deteriorated catalyst was taken out once a day. The addition of regenerated catalyst to the rich phase was repeated to maintain a constant cumulative methylation. At this time, the total phenol selectivity for 40 days was 98.0%. Also,
Days 0-10, Days 11-20, Days 21-30, 31
The phenol selectivity of each day was 96.0%,
It was 98.0%, 99.0%, and 99.0%.

Comparative Example 1 In the same manner as in Example 1, 2.5 kg of the catalyst was used to initiate the methylation reaction of phenol in a fluidized bed reactor having a diameter of 10 cm. At this time, the feed amount of phenol per hour per unit catalyst weight of 1 kg was adjusted to be 0.075 kg.

The raw material molar ratio was the same as in Example 1. The reaction was carried out continuously for 40 days, and the catalyst was neither extracted nor added. At this time, the total phenol selectivity for 40 days was 97.3%. Also, on days 0-10, 1
The phenol selectivity of each of the 1st to 20th days, the 21st to 30th days, and the 31st to 40th days was 96.0%, 98.0%, and 9%.
It was 8.2% and 97.0%.

[0038]

INDUSTRIAL APPLICABILITY According to the method of the present invention, an alkyl ortho position using a fluidized bed reactor capable of suppressing the by-product of impurities, enhancing the ortho position selectivity, and maintaining the high selectivity for a long period of time. It is useful as a continuous method for producing a modified phenol compound.

[Brief description of drawings]

FIG. 1 is FIG. 1 described on the last page of JP-A-56-49331.

FIG. 2 is a chart showing changes over time in the activities of the ortho-alkylation main reaction and the impurity formation side reaction when the alkylation reaction of phenols is carried out using a supported catalyst containing an iron oxide.

FIG. 3 is a chart showing changes with time in phenol selectivity when an alkylation reaction of phenols is carried out using a supported catalyst containing an iron oxide.

FIG. 4 is a diagram illustrating a method of carrying out an alkylation reaction of phenols using a supported catalyst containing an oxide of iron, withdrawing a certain amount of the catalyst from the reactor at a certain time, and a certain amount of the regenerated catalyst from the reactor to the reactor. 3 is a chart showing the change with time in phenol selectivity when the operation is continued while returning to the catalyst-rich phase portion.

[Explanation of symbols]

 A Reaction part B Regeneration part a, b Heat transfer tube 1 Catalyst transfer line (regenerated catalyst) 2 Catalyst transfer line (regenerated catalyst) 3 Raw material gas line 4 Reaction product gas line 5, 6 Regeneration gas line

Claims (1)

[Claims] 1. A method for producing an alkylated phenol compound by bringing phenols and alcohols into contact with each other in the gas phase using a fluidized bed reactor in the presence of a supported catalyst containing an iron oxide. And a regenerator, and extracting a certain amount of catalyst from the reactor at a certain time and adding a certain amount of regenerated catalyst from the regenerator to the catalyst rich phase portion of the reactor. A continuous method for producing an alkylated phenol compound.