JP3496949B2 - Method for producing ortho-methylated phenolic compound - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ortho-methylated phenol obtained by subjecting phenol and / or ortho-cresol to methanol in a gas phase in the presence of a metal oxide in a fluidized bed. In the method for producing a compound, the present invention relates to a method for efficiently producing ortho-cresol and 2,6-xylenol at a desired production ratio by improving the phenol conversion rate by providing at least one or more interpolated products horizontally. It is. [0002] All ortho-methylated phenol compounds produced by the method of the present invention are useful as industrial raw materials. For example, 2,6-xylenol is a raw material of polyphenylene ether and 2,6
-A raw material for xylidine, while orthocresol is useful as a raw material for pharmaceuticals, agricultural chemicals and the like. [0003] A method for producing an ortho-methylated phenol compound by bringing phenol or / or ortho-cresol into contact with methanol in the gas phase is known and is industrially practiced. Regarding a fluidized bed reaction, for example, Japanese Patent Publication No. 2-33693 discloses a method in which a metal oxide supported on silica is used as a catalyst to react in a fluidized bed. In general, if a reaction involving exothermic reaction is carried out using a fixed bed reactor, local heating is likely to occur. Particularly, in an industrial scale fixed bed reactor, it is extremely difficult to prevent local heating. This can lead to a decrease in product yield and selectivity and a reduction in catalyst life. [0005] In the ortho methylation of phenols, a decomposition reaction of methanol occurs. Since the decomposition of methanol is characterized by an accelerated increase at a high reaction temperature, the ortho-methylation reaction particularly requires a uniform reaction temperature. On the other hand, when a fluidized bed reactor is used, it is easy to keep the temperature inside the reactor uniform.
However, fluidized bed reactors also have problems to be solved. For example, the gas in the fluidized bed rises while mainly forming bubbles in the suspension phase of the catalyst particles, and repeats coalescence and re-dispersion during the ascent. The exchange of substances between the gas phase and the gas phase, the deterioration of gas mixing in each phase, and the contact efficiency between gas and solid are reduced. In extreme cases, the gas flows through, and the conversion rate is greatly reduced. . Therefore, in the prior art, the gas-solid contact efficiency is poor, the phenol conversion is low at the desired production ratio, and much less than orthocresol and 2,6-
Xylenol could not be efficiently co-produced. SUMMARY OF THE INVENTION An object of the present invention is to provide a gas phase catalytic reaction of phenol or / or orthocresol with methanol in a fluidized bed in the presence of a metal oxide to produce an ortho-methylated phenol compound. It is an object of the present invention to enable ortho-cresol and 2,6-xylenol to be efficiently co-produced at a desired production ratio. The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention, which is industrially extremely advantageous. That is, the present invention provides a method of manufacturing a phenol and / or ortho-methylated phenolic compound ortho-cresol and methanol to gas-phase catalytic reaction in a fluidized bed in the presence of a metal oxide, the gas distribution plate top of the catalyst to flow The reaction takes place
At least one or more locations have an opening ratio of 70 to 95%
A method for producing an ortho-methylated phenol compound, comprising using a reactor in which a certain insert is provided horizontally. When the phenol or / or ortho-cresol and methanol are reacted in a gas phase in a fluidized bed in the presence of a metal oxide to produce an ortho-methylated phenol compound, the gas in the fluidized bed is a catalyst suspension phase. It rises while forming bubbles mainly in the inside, and during the rise, coalescence and redispersion are repeated. For this reason, a gas flow-through phenomenon occurs, and the reaction in the fluidized bed generally has a lower conversion rate than the reaction in the fixed bed. According to the method of the present invention, since the insert is provided horizontally in the reactor, the bubbles can be divided, and the bubbles that have grown together can be divided and redispersed. Thereby, mass exchange between the suspension phase and the foam phase and gas mixing in each phase can be promoted, the contact efficiency between gas and solid can be improved, and a conversion rate close to that of a fixed bed can be obtained. As shown in FIG. 1, when the desired production ratio of ortho-cresol and 2,6-xylenol takes a certain value A, an attempt is made to increase the phenol conversion (for example,
According to curve n), the production ratio changes to B according to the curve n. That is, a product having a desired production ratio cannot be obtained. However, when the insert according to the method of the present invention is installed, the phenol conversion rate surprisingly increases while maintaining the desired production ratio A. That is, when an interpolant is installed, the correlation between the production ratio and the phenol conversion ratio is represented by a curve m
And the phenol conversion rate increases for an arbitrary production ratio as compared with the case where no insert is installed. As a result, the amount of unreacted phenol decreases due to the increase in the phenol conversion rate due to the installation of the insert. This leads to a reduction in the construction cost of the rectification column and the like when the unreacted phenol is reused as a raw material, and further, a reduction in the operation cost, which is economically advantageous. Hereinafter, the present invention will be described in detail. When producing an ortho-methylated phenolic compound by reacting phenol or / or ortho-cresol with methanol in the presence of a metal oxide in a gas phase in a fluidized bed reactor,
At least one or more inserts are provided horizontally in the reactor. The insert in the present invention may be of any type such as a lattice or a perforated plate. However, a lattice is preferably used because it can prevent the coalescence of bubbles and can evenly divide the bubbles and can increase the aperture ratio. Further, the position where the insert is provided is preferably not more than １ ／ of the height of the reactor. This is because, as shown in FIG. 2, the concentrated phase (phase having a large catalyst particle density) 2 , that is, the catalyst on the upper part of the gas dispersion plate
The part where the gas flows and the reaction takes place is almost half of reactor 1
This is because the provision of the inserts (lattices) 3, 3 ', 3 "has the effect of dividing bubbles.
In FIG. 2, reference numeral 4 denotes a dispersion plate, 5 denotes a source gas introduction pipe, and 6 denotes a reaction product gas outflow pipe. The number of inserts in the present invention may be one or a plurality. The effect is almost the same. However, when the height of the rich phase is high, it is preferable to provide a plurality of sheets. In the case where a plurality of inserts are used in the present invention, a plurality of inserts may be inserted at regular intervals in the height direction, or may be densely and densely. In the case of one sheet, it is preferable to install the sheet in the middle of the dense phase. The aperture ratio of the insert used in the present invention is 70%.
The content is preferably from 95% to 95%, more preferably from 80% to 90%. As the aperture ratio decreases, the circulation of the catalyst deteriorates, and local heating occurs. Also, if the aperture ratio increases, the contact efficiency does not increase. However, as shown in FIG. 3, the aperture ratio is the ratio of the area of the portion excluding the internal structure such as the heat removal tube and the rib 7 for attaching the insert 3 and the area of the opening. In the present invention, the gas linear velocity of the reactor is 0.5.
5 to 100 cm / sec. The particle diameter of the catalyst applied to the present invention is, for example, as described in JP-B-2-33693, the average particle diameter is 40 to 100 μm, and the average particle diameter is 0.2 to 0.7 times. , 1.5 to 2.0 times, and the total weight of particles in each particle size range exceeding 2.0 times is 5 to 50%, 5 to 30%, and 10% or less with respect to the total catalyst amount, respectively. . The components of the catalyst used in the present invention include, for example, JP-B-2-33693 and JP-B-63-34139.
As shown in the item, as the metal component, iron, vanadium, manganese, magnesium, chromium, there is a single or a combination of indium, further, alkali metal, alkaline earth metal, rare earth metal and the like to these components May be used. In the production of 2,6-xylenol and / or ortho-cresol according to the present invention, the molar ratio of methanol to phenol or / or ortho-cresol in the feedstock varies depending on the type of catalyst, but is 1: 1.
-20. In addition, steam or an inert gas can be introduced as needed. In the case of steam, the molar ratio to phenol and / or orthocresol is from 1: 0 to 1: 1.
5 is preferred. The reaction temperature depends on the type of catalyst, but 25
The range of 0-600 degreeC is preferable. The reaction can be carried out under normal pressure, reduced pressure or increased pressure. According to the present invention, the phenol conversion rate is improved, and ortho-cresol and 2,6-xylenol can be efficiently co-produced at a desired production ratio. The present invention will be described below with reference to examples. The phenol conversion and selectivity in the examples are defined by the following equations (1) and (2). In addition, ortho-cresol, 2,6-
The same applies to the xylenol selectivity. ## EQU1 ## ## EQU2 ## Example 1 A gas phase contact reaction was carried out in a fluidized bed reactor using a catalyst in which phenol and methanol were supported on silica and iron oxide and vanadium oxide. The catalyst was pure water 18 obtained by heating 8.8 kg of ammonium metavanadate (NH ₄ VO ₃ ) to 90 ° C.
Dissolve in 6.0 kg and add ferric nitrate (Fe
_{(NO 3) 3 · 9H 2} O) 30.3kg and 30 wt%
42.8 kg of silica sol (Snowtex N manufactured by Nissan Chemical Industries, Ltd.) containing SiO ₂ is added. 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 carried out by any of a centrifugal method, a two-fluid nozzle method and a high-pressure nozzle method, which are usually used industrially, but the centrifugal method is particularly preferred. In the centrifugal method, the particle diameter can be distributed between 10 and 150 μ suitable for use in a fluidized bed reactor by adjusting the rotation speed of the disk and the supply speed of the slurry. The obtained dry powder is preliminarily calcined at 350 ° C. for 2 hours using a tunnel kiln, and then calcined at 750 ° C.
The firing was performed for a time. Using 4.5 kg of this catalyst, a diameter of 4
One grid was placed in the middle of the dense phase portion having a height of 以下 or less in an inch reactor. The aperture ratio of the grating was 81%. The total amount of gas flowing out of the reactor was passed through a condenser, and the condensed liquid was analyzed by gas chromatography. Reaction temperature 336 ° C, raw material gas linear velocity 5 in the reactor
At cm / sec, the phenol conversion was 83.7%.
The results are shown in Table 1. Comparative Example 1 A reaction was carried out in the same manner as in Example 1, except that the grid of the reactor was removed. When the reaction temperature was 332 ° C., the raw material gas linear velocity in the reactor was 5 cm / sec, and the production ratio of ortho-cresol and 2,6-xylenol was the same as in Example 1, the phenol conversion was 73.6%. . The results are shown in Table 1. Example 2 A reaction was carried out in the same manner as in Example 1, except that three lattices of the reactor were arranged at substantially equal intervals in the dense phase portion. When the production ratio of ortho-cresol and 2,6-xylenol was the same as in Example 1 at a reaction temperature of 333 ° C. and a raw material gas linear velocity in the reactor of 5 cm / sec, the phenol conversion was 82.8%. The results are shown in Table 1. Example 3 A reaction was carried out in the same manner as in Example 1, except that five lattices of the reactor were arranged at substantially equal intervals in the dense phase portion. When the production ratio of ortho-cresol and 2,6-xylenol was the same as in Example 1 at a reaction temperature of 333 ° C. and a raw material gas linear velocity in the reactor of 5 cm / sec, the phenol conversion was 82.8%. The results are shown in Table 1. [Table 1]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing a correlation between a production ratio of ortho-cresol and 2,6-xylenol and a phenol conversion rate. FIG. 2 is an explanatory diagram showing the relationship between a catalyst rich phase and an insert (lattice) in a reactor. FIG. 3 is a partially oblique view of the reactor for explaining the opening ratio of the insert.・

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-86428 (JP, A) JP-A-63-222136 (JP, A) JP-A-59-144726 (JP, A) (Vol. 4) "(December 30, 1960) Published by Kyoritsu Publishing Co., Ltd., p. 564-565 “Jamaita” (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07C 39 / 07,37 / 16

Claims (1)

(57) [Claim 1] In a process for producing an ortho-methylated phenolic compound, a gas- phase reaction of phenol or / and / or ortho-cresol with methanol in a fluidized bed in the presence of a metal oxide is carried out. The catalyst at the top of the dispersion plate flows and reacts
Is performed at least at one or more locations where the aperture ratio is 70.
A method for producing an ortho-position methylated phenol compound, comprising using a reactor in which an interpolated product of up to 95% is provided horizontally.