JP3519427B2 - Continuous production method of ortho-alkylated phenol compound - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phenol and an alcohol in the presence of a supported catalyst containing an oxide of iron.
The present invention relates to a method for continuously producing an ortho-alkylated phenol compound by gas-phase contact using a fluidized bed reactor. The ortho-alkylated phenolic compounds produced by the method of the present invention are important as industrial raw materials, respectively. For example, ortho-cresol is a raw material for agricultural drugs and epoxy resins, 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] Hitherto, as a method for producing an ortho-alkylated phenol, a method relating to a catalyst system to be used has been mainly used, and a method mainly comprising iron, vanadium, manganese, magnesium or the like has been known. ing. Regarding the improvement of activity and ortho-position selectivity, see JP-B-47-37943.
The improvement can be generally achieved by using a catalyst containing vanadium oxide and iron oxide as described in the publication. However, even when this catalyst is used, the selectivity of phenols is low in the early stage and late stage of the reaction, and it 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 JP-A-331, the reaction and the regeneration of the catalyst are carried out in parallel by a reaction device composed of a reaction portion and a catalyst regeneration portion, or a reaction device composed of two or more lines. Disclosed are methods in which the catalyst is used for the reaction in a cycle or alternately. Further, FIG. 1 shows the drawing described in the last page of JP-A-56-49331. 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. To be added. However, the purpose of this continuous production method is to obtain a stable product quality without changing the separation and purification steps following the reaction as described in the gazette, and to increase the selectivity of phenols, Moreover, there is no idea or disclosure of maintaining the high selectivity for a long period of time. For industrial production, it is natural that stable production is performed with stable quality, and it is desired to obtain higher selectivity and maintain high selectivity for a long time. . An object of the present invention is to provide an ortho-alkylated phenol capable of suppressing by-products of impurities, increasing ortho-selectivity, and maintaining the high selectivity for a long period of time. It is an object of the present invention to provide a continuous production method. Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a method for producing an ortho-alkylated phenol that suppresses the by-product of impurities and has enhanced ortho-position selectivity. As a result, in the presence of a supported catalyst containing iron oxide,
When performing a gas phase contact reaction using a fluidized reactor, it has been found that it is desirable to extract the catalyst on the way and to add the regenerated catalyst to the dense phase portion of the reactor, and have accomplished the present invention. In the method of the present invention, when a phenol and an alcohol are brought into contact with each other in a gas phase by using a fluidized bed reactor to carry out alkylation, a supported catalyst containing an oxide of iron is withdrawn in the middle and a concentrated phase is removed. And a method for continuously producing an ortho-alkylated phenol compound. As the catalyst composition, vanadium other than iron,
Chromium and alkali metals may be contained. When vanadium is contained in addition to iron, vanadium and iron of the catalyst include oxides of various valences, and 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 , VO, etc. are good, and in the case of iron, Fe ₂ O ₃ , Fe ₃ O ₄ , FeO, etc. are good. The catalyst can be made by various preparation methods.
Vanadium sources include its oxides, ammonium salts,
Use 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 an appropriate carrier such as alumina or diatomaceous earth. However, a carrier need not necessarily be used. The starting phenols to which the method of the present invention is applied include phenol, ortho-cresol, meta-cresol, para-cresol, xylenols other than 2,6-xylenol, ortho-ethylphenol, ortho-propylphenol, ortho-tert-butylphenol and the like. However, as raw material alcohols, methanol, ethanol, n-propanol and the like can be mentioned, and as the ortho-alkylated phenol obtained by the reaction, ortho-cresol, 2,6-xylenol, 2,4-xylenol, 2,3 , 5-trimethylphenol, 2,3,6-
There are trimethylphenol, 2,4,6-trimethylphenol and the like. Hereinafter, the present invention will be described in detail. According to the study of the present inventors, on a supported catalyst containing an oxide of iron, the activity degradation curves of the main reaction of ortho-alkylation and the side reaction of impurity formation in the above reaction,
That is, the time-dependent decrease in the reaction rate constant is represented as shown in FIG. Accordingly, the change over time of the phenol selectivity represented by the following formula 1 is represented as shown in FIG. [Equation 1] That is, when the alkylation reaction is carried out with a constant amount of catalyst as shown in FIGS. 2 and 3 on a constant production basis, the phenol selectivity is low at the point A in the initial stage of the reaction, and the reaction in which the activity of the catalyst is slightly deteriorated is slightly increased. At the point B in the middle stage, the selectivity of phenols is maximized, and further, at the point C of the late stage of the reaction in which the activity of the catalyst deteriorates, the selectivity of phenols becomes low. Based on this fact, the present inventors, in order to maintain the phenols selectivity at a constant high level on a constant production basis, after starting the reaction, change the catalyst deterioration state to the state of point B in FIGS. 2 and 3. It is important to maintain the state at the point B by adding the regenerated catalyst to the catalyst rich phase portion of the reactor while extracting the deteriorated catalyst in accordance with the progress of the deterioration, and By separately providing a reactor and a regenerator, it was found that it is possible to continuously produce ortho-alkylated phenol compounds while keeping the phenol selectivity at a constantly high level as shown in FIG. The present invention has been developed. Specifically, to maintain the state of the catalyst at the point B means that the integrated alkylation amount represented by the following equation 2 is set to 0.1.
4-0.8 (kmol ortho-alkylation / kg of catalyst)
Is achieved by keeping Preferably, the integrated alkylation amount is 0.5 to 0.7 (ortho-alkylation kmol /
Catalyst kg). ## EQU2 ## That is, by keeping the accumulated amount of alkylation substantially constant, the ortho-alkylated phenol compound can be continuously produced while maintaining the deteriorated state of the catalyst near the point B having the highest phenol selectivity. With respect to the method of extracting and adding the catalyst, the method may be continuous or batch, and the phenol selectivity can be increased. However, in either case, 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 be the same. In addition, the amount of extraction and additional amount can be determined if the integrated amount of alkylation to be maintained and the amount of catalyst in the reactor are determined. The catalyst rich phase portion refers to a portion where the catalyst density is high in the reactor. For example, in a fluidized bed reactor, it is a portion which is approximately １ ／ or less of the height of the reactor, and a catalyst is added thereto. Is preferred. It is needless to say that the timing for starting the extraction and the addition of the catalyst is preferably in the vicinity of the point B which gives the highest phenol selectivity in FIG. The reaction temperature ranges from 250 to 550 ° C., preferably from 300 to 400 ° C. At a temperature of 250 ° C. or lower, the reaction rate of phenols is low, and at a temperature of 550 ° C. or higher, many compounds other than the ortho position are by-produced, and futile decomposition of alcohols also occurs. The reaction pressure can 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, steam, nitrogen, hydrogen, carbon monoxide, carbon dioxide, methane and other gases may coexist in addition to the raw materials of phenols and alcohols. 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 equation (3). (Equation 3) The integrated methylation amount is defined by the following equation (4). (Equation 4) (Example 1) Gas phase contact reaction of phenol and methanol was carried out 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 ) is 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 a fine particle suspension uniformly dispersed in the silica sol colloid is obtained. This was dried with a cocurrent spray dryer. The atomization of the raw material slurry can be performed by any of a centrifugal system, a two-fluid nozzle system and a high-pressure nozzle system which are usually used industrially, but the centrifugal system is particularly preferable. In the centrifugal method, the particle diameter is adjusted to 10 to 15 suitable for use in a fluidized bed reactor by adjusting the rotation speed of the disk and the supply speed of the slurry.
It can be distributed between 0 μm. The obtained dried powder was preliminarily calcined at 350 ° C. for 2 hours using a tunnel kiln, and then calcined at 700 ° C. for 5 hours.
The firing was performed for a time. Using 2.5 kg of this catalyst, a diameter of 10 c
The phenol methylation reaction was initiated in a m fluidized bed reactor. At this time, the feed amount of phenol per hour per unit weight of 1 kg of the catalyst was adjusted to be 0.075 kg. The raw material molar ratio was phenol: methanol:
A 1: 5: 3 water solution was used. The reaction was carried out for 40 consecutive days, and after the accumulated methylation amount reached 0.6 (kmol ortho methylation / kg of catalyst) on the 20th day, once a day, the deteriorated catalyst was extracted. The addition of the regenerated catalyst to the concentrated phase was repeated to keep the integrated methylation amount constant. At this time, the total phenol selectivity for 40 days was 98.0%. Also,
0-10 days, 11-20 days, 21-30 days, 31
The phenol selectivity for each of ４０40 days is 96.0%,
98.0%, 99.0% and 99.0%. Comparative Example 1 In the same manner as in Example 1, a phenol methylation reaction was started in a fluidized bed reactor having a diameter of 10 cm using 2.5 kg of a catalyst. At this time, the feed amount of phenol per hour was adjusted to 0.075 kg per 1 kg of the unit catalyst weight. The molar ratio of the raw materials was the same as in Example 1. The reaction was performed continuously for 40 days, and no catalyst was withdrawn or added. At this time, the total phenol selectivity for 40 days was 97.3%. Also, on days 0-10, 1
The phenol selectivities on days 1-20, 21-30, 31-40 were 96.0%, 98.0%, 9
8.2% and 97.0%. According to the method of the present invention, a fluidized bed reactor capable of suppressing by-products of impurities, increasing ortho-site selectivity and maintaining the high selectivity for a long time is used. It is useful as a continuous method for producing an ortho-alkylated phenol compound.

BRIEF DESCRIPTION OF THE 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 activities of an ortho-alkylation main reaction and an impurity generation side reaction when an alkylation reaction of phenols is performed using a supported catalyst containing an oxide of iron. FIG. 3 is a table showing a change over time in phenol selectivity when an alkylation reaction of phenols is carried out using a supported catalyst containing an oxide of iron. [FIG. 4] A phenol alkylation reaction uses a supported catalyst containing an oxide of iron to extract a certain amount of catalyst from a reactor for a certain period of time, and to remove a certain amount of regenerated catalyst from the reactor. 4 is a table showing the change over time in the phenol selectivity when the operation is continued while returning to the catalyst rich phase portion of FIG. [Description of Signs] A Reaction part B Regeneration parts 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

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-116188 (JP, A) JP-A-5-286880 (JP, A) JP-A-63-188636 (JP, A) JP-A-58-1988 183635 (JP, A) JP-A-59-144726 (JP, A) JP-A-56-46331 (JP, A) JP-A-56-49330 (JP, A) JP-A-53-53627 (JP, A) JP-B-47-37943 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 39/00 C07C 37/00

Claims (1)

(57) [Claim 1] An alkylated phenol by contacting a phenol and an alcohol in the gas phase using a fluidized bed reactor in the presence of a supported catalyst containing an oxide of iron. In a method for producing a compound, a reaction apparatus and a regenerating apparatus are provided, and the integrated amount of alkylation is 0.4 to 0.8 (ortho-position
(Kmol / kg of catalyst), a certain amount of catalyst is withdrawn from the reactor at a certain time and a certain amount of regenerated catalyst is added from the regenerator to the catalyst rich phase portion of the reactor. A method for continuously producing an ortho-alkylated phenol compound.