JPH0741437A - Purification method of monoalkenylbenzenes - Google Patents

Abstract

(57) [Abstract] [Purpose] After the side chain of an aromatic hydrocarbon compound in which one or more hydrogen atoms are bonded to the α-position of the side chain is alkenylated with a diolefin to synthesize a monoalkenylbenzene, the reaction Develop a method for purifying and obtaining monoalkenylbenzene with high purity and high recovery rate from the product solution. [Structure] An alkali metal-based supported catalyst contained in a reaction product liquid is prepared by using a solid acid, a carbon material, an ion exchange resin, or the like.
A method for purifying monoalkylbenzene by distillation after deactivating and removing.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the use of a conjugated diene having 4 or 5 carbon atoms in the side chain of an aromatic hydrocarbon compound in which one or more hydrogen atoms are bonded to the α-position of the side chain. The present invention relates to a method for producing monoalkenylbenzenes by alkenylation with a metal catalyst, and then purifying and obtaining monoalkenylbenzenes from a reaction product liquid. Monoalkenylbenzenes are useful as intermediate raw materials for various organic compounds such as polymer monomers and pharmaceuticals. For example, O
5- (O-tolyl) -2-pentene produced from xylene and 1,3-butadiene is converted to industrially useful 2,6 naphthalenedicarboxylic acid by ring-closing, dehydrogenation, isomerization and oxidation. be able to.

[0002]

As a catalyst for producing monoalkenylbenzenes by alkenylating side chains of aromatic hydrocarbon compounds with conjugated dienes having 4 or 5 carbon atoms, alkali metals such as sodium and potassium and those Alloy, a method of using a mixture obtained by heat-treating a mixture of a basic potassium compound and alumina to a carrier obtained by calcining a mixture of sodium and an alkali metal oxide or an alkaline earth. A method is known in which a metal oxide is loaded with metal sodium or metal potassium and used. Of these catalysts, the reaction product liquid obtained by using alkali metals such as sodium and potassium and their alloys, after the reaction is completed, the product liquid is cooled and allowed to stand, and the catalyst and the target product are decanted or filtered. It is known that when the method of separating and recovering the monoalkenylbenzenes by separation into a liquid phase containing is contained, the quality of the monoalkenylbenzenes is changed and the monoalkenylbenzenes cannot be obtained with high recovery. Has been.

In order to solve the above problems, various treatment methods have been proposed in the case of using an alkali metal such as sodium or potassium or an alloy thereof as a catalyst. In Japanese Unexamined Patent Publication No. 51-4127, the total concentration of alkali metal and organic alkali metal compound in a hydrocarbon used as a raw material for distillation is determined as 0.
Proposals have been made that the range is from 09 to 15 milligram atoms. However, in this method, not all of the alkali metal catalyst component is removed, but a part is mixed in the liquid phase as a soluble alkyl or alkenyl complex. When this product liquid is directly introduced into the distillation column, the monoalkenylbenzenes further react with unreacted alkylbenzenes and monoalkenylbenzenes due to the coexistence of an active catalyst to generate a high molecular weight by-product, By a reverse reaction, it returns to the starting material, alkylbenzenes, or moves double bonds to produce isomers other than the desired monoalkenylbenzene. That is, lowering the total concentration of the alkali metal and the organic alkali metal compound only reduces the degree thereof, and it is impossible to prevent the deterioration at all. Further, when the distillation column is operated for a long period of time, the trace amount of alkali metal and organic alkali metal compound is concentrated in the distillation column, and finally it becomes impossible to obtain high-purity monoalkenylbenzenes, and the recovery rate is also lowered. I will end up.
Deterioration of monoalkenylbenzene can be suppressed to some extent by lowering the distillation temperature, but for that purpose distillation must be carried out under reduced pressure so that no alteration of monoalkenylbenzene occurs. Requires a high vacuum, which is unrealistic due to industrially high equipment and operating costs.

Further, in Japanese Patent Application Laid-Open No. 49-70929, a method in which a catalyst is separated and removed from a reaction product solution and then treated with carbon dioxide and distilled, or a reaction product solution is treated with carbon dioxide and then the catalyst is separated and removed and distilled Is proposed. In this method, the alkali metal and the organic alkali metal compound are completely deactivated by the carbon dioxide treatment, and it is possible to prevent the alteration of the monoalkenylbenzene during the distillation. Part of it is soluble in an organic solvent and is introduced into the distillation column. Then, when unreacted aromatic hydrocarbons are distilled out in the distillation, alkali salts having a solubility or higher are deposited as solids and accumulated inside the distillation column. Therefore, not only the gas-liquid contact in the distillation column is reduced and the distillation efficiency is reduced, but finally the distillation column is closed and the distillation operation cannot be performed. That is, unless the alkali metal component is completely removed, the distillation column can be operated stably and high-purity monoalkenylbenzenes cannot be obtained.

Japanese Patent Publication No. 57-26489 proposes a method in which alkenylbenzene and water are brought into contact with each other, and then the pH of water is adjusted to 6 or less to make the alkali metal catalyst water-soluble and then separated. However, this method has a risk of generating a large amount of reaction heat and igniting when the reaction product liquid is brought into contact with water. Although it is possible to control the reaction to some extent by the amount of water or the reaction product liquid to be brought into contact, when it is attempted to carry out the reaction on an industrial scale, it requires a long processing time, the equipment becomes large-scale, and it is a practical method. I can't say. See also USP
No. 3,244,758, isopropanol is added before the distillation to inactivate the alkali metal or the alkali metal compound contained in the production liquid, thereby preventing an undesirable side reaction from occurring during the distillation. In this method, it is possible to avoid the generation of a large amount of reaction heat and the risk of ignition that occur when contacting water, but the deactivated alkali metal catalyst is introduced into the distillation column as an alkali metal alcoholate soluble in an organic solvent, It causes such problems as described above and is not preferable. Further, these proposals are treatment methods in the case of using an alkali metal such as sodium or potassium or an alloy thereof as a catalyst. Alkali metals such as sodium and potassium and their alloys have extremely high ignitability, and it is extremely difficult industrially to use them.

On the other hand, in addition to these alkali metals and alloys, it is known that a catalyst in which a carrier carries an alkali metal is effective for the alkenylation reaction. Of these catalysts, the catalysts prepared by the following treatments have been found to exhibit very high activity for the alkenylation reaction and at the same time have a significantly low ignition quality. That is, a carrier obtained by firing a mixture of potassium hydroxide and alumina hydrate, a carrier obtained by firing a mixture of a basic potassium compound and alumina, and an alkaline earth metal oxide containing a potassium compound. Substance carrier, a zirconium oxide carrier containing a potassium compound, and an alkali metal-based supported catalyst obtained by heat-treating these carriers with addition of metallic sodium under an inert gas is used as a catalyst for alkenylation reaction. It exhibits high activity and, at the same time, significantly suppresses ignitability. No proposal has been made yet regarding a treatment method using these alkali metal-based supported catalysts.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention refined monoalkenylbenzenes by allowing a reaction product solution obtained by using an alkali metal-based supported catalyst to stand and separating the catalyst by filtration, followed by distillation. When I tried to get
Degradation of monoalkenylbenzenes occurred in the distillation step, and it was not possible to obtain a product with high purity and good recovery. Moreover, accumulation of insoluble compounds occurred in the distillation column, which reduced the distillation efficiency of the target substance and eventually clogged the distillation column, making it impossible to carry out the distillation operation. That is, the reaction product solution was allowed to stand and filtration was attempted to separate the catalyst and the liquid phase containing the target substance, but the particulate catalyst could not be completely removed,
Further, a part of the alkali metal is mixed in the liquid phase as a soluble alkyl or alkenyl complex. When this product liquid is directly introduced into the distillation column, the monoalkenylbenzenes further react with unreacted alkylbenzenes and monoalkenylbenzenes due to the coexistence of an active catalyst to generate a high molecular weight by-product, Since it is returned to the starting alkylbenzenes by the reverse reaction or isomers other than the target monoalkenylbenzenes are generated by the movement of the double bond, it is not possible to obtain high-purity monoalkenylbenzenes and the recovery rate is also high. Will fall.

The deterioration of the monoalkenylbenzene can be suppressed to some extent by lowering the distillation temperature, but for that purpose, it is necessary to carry out distillation under a reduced pressure, so that the deterioration of the monoalkenylbenzene does not occur at all. It requires a high vacuum, which is industrially expensive and unrealistic. In addition, a part of the alkali metal is introduced into the distillation column as an alkali salt soluble in an organic solvent, and when unreacted aromatic hydrocarbons are distilled off in the distillation, the alkali salt having a solubility or higher is precipitated as a solid and the distillation column is used. It accumulates inside. Therefore, not only the gas-liquid contact in the distillation column is reduced and the distillation efficiency is reduced, but finally the distillation column is closed and the distillation operation cannot be performed. Therefore, this problem cannot be avoided only by operating conditions of distillation. In view of the above facts, an object of the present invention is to develop a method for separating and recovering monoalkenylbenzenes from a reaction product solution obtained by using an alkali metal-based supported catalyst in high purity with a high recovery rate.

[0009]

Means for Solving the Problems The present inventors have prepared monoalkenylbenzenes by alkenylating an α-position of an aromatic hydrocarbon compound with a supported catalyst of an alkali metal using conjugated dienes having 4 or 5 carbon atoms. Then, as a result of extensive studies on a method of separating and recovering the monoalkenylbenzenes from the reaction product solution, after deactivating and / or removing the alkali metal-based catalyst in the reaction product solution, the monoalkenylbenzenes are distilled to remove the monoalkenylbenzenes. It was found that the monoalkenylbenzenes can be purified with high purity and high recovery rate by separating and recovering, and thus the present invention has been completed. That is, in the present invention, the reaction product liquid is subjected to treatment operations such as contact with a solid acid, a carbon material, a cation exchange resin, etc., and filtration, etc. to deactivate or remove the alkali metal-based catalyst, and then distill it. This is a method for separating and recovering monoalkenylbenzenes purified by.

The present invention will be described in detail below.
As the aromatic hydrocarbon compound in which one or more hydrogen atoms are bonded to the α-position of the side chain used in the present invention, the following compounds are used. Examples of monocyclic aromatic hydrocarbons include monoalkylbenzenes such as toluene, ethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, sec-butylbenzene and isobutylbenzene, o-, m- and p-xylene, o-, Dialkylbenzenes such as m- and p-ethyltoluene, o-, m- and p-diethylbenzene, trialkylbenzenes such as mesitylene and pseudocumene, 1, 2, 3, 5
Polyalkylbenzenes such as -tetramethylbenzene, 1,2,4,5-tetramethylbenzene, pentamethylbenzene and hexamethylbenzene are used, and polycyclic aromatic hydrocarbons include 1- and 2-methylnaphthalene, Dimethylnaphthalene, tetrahydronaphthalene,
Indane or the like is used. 4 carbon atoms as one raw material
Alternatively, as the conjugated dienes of 5, 1,3-butadiene, 1,3-pentadiene and isoprene are used.

The alkali metal supported catalyst used in the present invention is a carrier obtained by calcining a mixture of potassium hydroxide and alumina hydrate at 350 to 700 ° C,
The mixture of the basic potassium compound and alumina is 350-
A carrier obtained by calcination at 700 ° C, an alkaline earth metal oxide carrier containing a potassium compound, a zirconium oxide carrier containing a potassium compound, and these carriers at 100 to 300 ° C under an inert gas. There is a mixture obtained by adding sodium metal and heat-treating it. Although various reaction methods are adopted in using these catalysts in the reaction, generally, a method in which an aromatic hydrocarbon, which is one of the starting materials, is present in excess with respect to the conjugated diene is a monoalkylbenzene. It is possible to improve the selectivity to the class.
For that purpose, a method of continuously supplying the conjugated dienes to the reaction system by a semi-batch method is preferable. When the reaction is carried out continuously by a complete mixing system or a fixed bed flow system, the reactor is divided into multiple stages and the conjugated dienes are fed to each stage to reduce the concentration of conjugated dienes in the reactor. It is preferable to employ a reaction system that can achieve high selectivity.

The reaction temperature in the method of the present invention is 100 to
It is in the range of 200 ° C. If it is lower than this, the reaction will occur, but a sufficient reaction rate cannot be obtained, and the selectivity tends to decrease. If the temperature is higher than this, by-products such as tar content increase, which is not preferable. In the present invention, the reaction is carried out under conditions in which the starting aromatic hydrocarbon and the product are in a substantially liquid state. The reaction pressure is not particularly limited as long as it is a pressure sufficient to allow the raw material aromatic hydrocarbon and the product to substantially exist as a liquid, but is not specifically limited, but is 0.05 to 5 atm in absolute pressure, preferably 0.1 atm. ~ 2 atm. The ratio of the conjugated diene having 4 or 5 carbon atoms, which is one of the raw materials, to the aromatic hydrocarbon as the raw material in the method of the present invention is generally 0.01 to 1, preferably 0.03 to 0.5 in molar ratio. Is. When the amount of the diene is larger than this, the produced monoalkenylbenzene further reacts with the diene to increase the production of a compound in which two or more molecules of the diene are added to one molecule of the aromatic hydrocarbon, and the polymerization of the diene is likely to occur. It is not preferable because the rate is lowered. The amount of the catalyst used in the method of the present invention is 0.01 by weight based on the starting aromatic hydrocarbon.
% Or more, preferably 0.05% or more. The method of the present invention employs a reaction method such as a batch method, a semi-batch method, or a complete mixing / flowing method. The reaction time in the batch method, the semi-batch method, or the residence time in the complete mixing / flowing method is 0.1 to 10 hours. Is adopted. In the case of a fixed bed flow system, the LSV of aromatic hydrocarbon is usually 0.1 to
10h ^-1 is adopted.

When the reaction is carried out by suspending the catalyst, usually, after the reaction, the produced liquid is allowed to stand and most of the catalyst is first settled.
Next, the product solution is extracted from the reaction tank and processed. At this time, as one method, first, most of the alkali metal-based supported catalyst is removed by filtration using a filter of 5 microns or less. When a filter having a coarser mesh than this is used, a part of the particulate catalyst is contained in the recovered product solution, which causes the alteration of monoalkylbenzene in the distillation step, which is not preferable. Also,
Even if the alkali metal-based catalyst is removed by filtration using a filter of 5 microns or less, part of the alkali metal is mixed in the liquid phase as a soluble alkyl or alkenyl complex or alkali salt. When this product liquid is directly introduced into the distillation column, the active soluble catalyst causes alteration of the monoalkenylbenzene. Although the amount of the soluble catalyst is not large at all, when it is concentrated in the distillation column retention liquid and operated for a long period of time, the deterioration of the monoalkenylbenzene increases to a nonnegligible amount. Therefore, the active soluble catalyst needs to be deactivated before the product liquid is introduced into the distillation column.

Another method is to first deactivate the alkali metal catalyst component from a production liquid containing a fine particulate insoluble alkali metal-based supported catalyst and a soluble alkyl or alkenyl complex or an alkali salt, and then to remove the alkali metal catalyst component of 5 μm or less. This is a method of filtering and removing the alkali metal-based catalyst using a filter. Although any of the above methods can be used, when the first method is used, the active alkali metal-based catalyst collected on the filter causes alteration of the monoalkenylbenzene on the filter to give a high molecular weight monoalkenylbenzene. May form a polymer and cause filter clogging. Therefore, the latter method is more preferably used. Part of the carrier of the alkali metal-based supported catalyst is formed into fine particles and contained in the produced liquid, and the whole amount cannot be removed only by sedimentation. Therefore, it is necessary to perform the solid removal operation by the filter.

To deactivate and / or remove the catalyst, a method of contacting with a solid acid, a carbon material or a cationic ion exchange resin is adopted. When a solid acid is used, the alkali metal component in the alkali metal-based supported catalyst which is active due to the acid-base reaction is adsorbed on the solid acid and can be deactivated and / or removed. As the solid acid that can be used, activated clay,
Alumina, silica-alumina, various zeolites, etc. are available. When a zeolite is used, a hydrogen ion exchange type zeolite is particularly preferably used, and mordenite, Y
Type, X type, ZSM type, ferrierite, etc. are not particularly limited in kind. When a carbon material is used, the alkali metal component in the active alkali metal-based supported catalyst must be adsorbed on a functional group such as a surface hydroxyl group or a carboxylic acid group, or occluded in the carbon material by an intercalation mechanism. Can be deactivated and / or removed. The carbon material that can be used is not particularly limited, such as graphite, activated carbon, amorofus carbon obtained by firing petroleum-based and coal-based pitch, PAN-based carbon fiber, and the like, if necessary, fired, oxidized, carbonized, The surface functional group and surface area can be adjusted before use. When a cationic ion exchange resin is used, the alkali metal component in the active supported alkali metal catalyst due to the acid-base reaction is adsorbed by the functional group on the cationic ion exchange resin and deactivated and / or removed. You can Cationic ion exchange resins that can be used include sulfonic acid type and carboxylic acid type, and ion exchange resins having a higher degree of swelling and a higher degree of crosslinking are preferable.

When contacting these solids with the product liquid,
When there is a risk of generation of high reaction heat or ignition at the time of deactivation of the alkali metal-based catalyst, the deactivation reaction can be controlled at appropriate times by introducing the solid or the product solution. In addition, a gas such as air, oxygen, water vapor, a mixed gas of carbon dioxide and oxygen, a mixed gas of carbon dioxide and water vapor, or a liquid such as water, an acid aqueous solution, or alcohol is brought into contact with the produced liquid to preliminarily carry an alkali metal-based support. It is also possible to employ a method of deactivating the catalyst to some extent and then bringing these solids into contact with the resulting liquid to completely deactivate and / or remove the alkali metal-based supported catalyst. The contact time is not particularly limited as long as it is a time sufficient to deactivate and / or remove the active supported alkali metal catalyst. The contact temperature can be selected within a wide range from room temperature to the boiling point of the starting aromatic hydrocarbon, but room temperature is sufficient. As the contact method, a batch method, a semi-batch method, a fixed bed flow method, or the like is adopted, but any method does not pose a problem as long as solid-liquid contact is sufficient. The amount of solid used is
The amount may be sufficient to remove the alkali metal component.

[0017]

As described above, when the alkenylbenzene is separated and recovered from the alkenylbenzene product by distillation, the alkali metal-supported catalyst may be deactivated and / or removed in advance so that it is also modified by atmospheric distillation. Does not occur, high-purity alkenylbenzene can be obtained at a high recovery rate, the distillation column can be operated stably, and its industrial significance is extremely large.

[0018]

EXAMPLES The method of the present invention will be described in detail below with reference to Examples and Comparative Examples. The present invention is not limited to the scope of the examples below. Example 1 To an aqueous solution containing 2.09 kg of KOH, 5.8 kg of Al ₂ O ₃ powder (DN-1A manufactured by Mizusawa Chemical Co., Ltd.) was added, and stirred and mixed at room temperature for 1 hour. After drying overnight at 115 ° C, it was further calcined in air at 500 ° C. 500g of this mixed baked product
Was stirred at 150 ° C under a nitrogen atmosphere to obtain 60 g of metallic Na.
Was added and stirred for 30 minutes. O-xylene 100k dehydrated by molecular sieve was added to the catalyst powder obtained here.
g in a nitrogen stream and heated to 140 ° C. 7.0 kg of 1,3-butadiene is added to 1 while stirring under normal pressure.
Introduced over time to react. After the reaction, stirring was stopped, the mixture was allowed to stand and the temperature was lowered, and the product liquid was extracted. A part of this product solution was collected and analyzed by gas chromatography. The results are shown in Table 1. The 5- (O-tolyl) -2-pentene selectivity based on 1,3-butadiene was 83.0%.

This reaction product solution is passed through a fixed bed column packed with activated clay to completely adsorb the alkali metal-supported catalyst, deactivate and remove it, and then the reaction product solution is further made into stainless steel having a pore size of 1 micron. It was passed through a sintered metal filter. 10 kg of this product solution was put into the orthoxylene recovery tower.
It was introduced at a rate of hr. Table 2 shows the compositions and weights of the top liquid and the liquid discharged from the kettle when the orthoxylene recovery tower was operated at a kettle temperature of 230 ° C under normal pressure. Deterioration of 5- (O-tolyl) -2-pentene in the kettle effluent, which was the desired product, was not observed. Next, the 5- (O-tolyl) -2-pentene purification column was operated under atmospheric pressure at a kettle temperature of 250 ° C., and 5- (O-tolyl) -2-pentene was recovered from the top of the column. The purity was 99.8% and the recovery rate was 98.5%.

Example 2 The procedure of Example 1 was repeated, except that the adsorption and deactivation of the alkali metal-based supported catalyst were carried out using hydrogen ion type mordenite. The purity of 5- (O-tolyl) -2-pentene is 99.
It was 7% and the recovery rate was 98.4%. Example 3 The same procedure as in Example 1 was carried out except that the adsorption and deactivation removal of the alkali metal-based supported catalyst were performed with activated carbon. The purity of 5- (O-tolyl) -2-pentene was 99.6% and the recovery rate was 98.4%.

Example 4 The same procedure as in Example 1 was carried out except that graphite was used to deactivate the alkali metal-based supported catalyst. 5-
The (O-tolyl) -2-pentene purity was 99.6%, and the recovery rate was 98.8%. Example 5 The procedure of Example 1 was repeated, except that the adsorption and deactivation of the alkali metal-based supported catalyst were performed using a sulfonic acid ion exchange resin (Amberlyst 15). 5- (O-tolyl)
-2-Pentene purity is 99.6%, recovery rate is 9
It was 8.9%. Example 6 CaO 5 in an aqueous solution containing 2.09 kg of KOH.
Add 8 kg, stir at room temperature for 1 hour and mix, 115 ° C
The same procedure as in Example 1 was performed, except that the carrier was dried at 500 ° C. overnight and then calcined in air at 500 ° C. The purity of 5- (O-tolyl) -2-pentene was 99.5%, and the recovery rate was 98.3%. Example 7 An aqueous solution containing 2.09 kg of KOH was added with ZrO ₂ .
Add 8 kg, stir at room temperature for 1 hour and mix, 115 ° C
The same procedure as in Example 1 was performed, except that the carrier was dried at 500 ° C. overnight and then calcined in air at 500 ° C. 5- (O-
Trilyl) -2-pentene purity was 99.8% and the recovery was 98.1%.

Comparative Example 1 In Example 1, the product solution after the alkenylation reaction was allowed to stand still, the temperature was lowered, and then the product was taken out. This product liquid was directly introduced into the orthoxylene recovery column at a rate of 10 kg / hr without passing through the filter. Table 2 shows the compositions and weights of the top liquid and the liquid discharged from the kettle when the orthoxylene recovery tower was operated at a kettle temperature of 230 ° C under normal pressure. Deterioration of 5- (O-tolyl) -2-pentene in the kettle liquor, which is the desired product, occurs 5-
(O-Tolyl) -2-pentene is a high-boiling component further reacted with ortho-xylene, an increase in ortho-xylene due to a reverse reaction of an alkenylation reaction, and a transfer of a double bond of 5- (O-tolyl) -2-pentene. Formation of 5- (O-tolyl) -3-pentene and 5- (O-tolyl) -4-pentene, which are isomers, was observed.

Comparative Example 2 In Example 1, the product solution after the alkenylation reaction was allowed to stand still and the temperature was lowered, and then the reaction product solution was extracted through a stainless sintered metal filter having a pore size of 1 micron. This product liquid was directly introduced without deactivating the alkali metal catalyst component into the orthoxylene recovery column operating under the reduced pressure of 20 mmHg and the kettle temperature of 120 ° C. at a rate of 10 kg / hr. Table 2 shows the compositions and weights of the top liquid and the kettle liquid one day after the operation of the ortho-xylene recovery column. 5- (O
The mass change of -tolyl) -2-pentene was reduced, but the by-product could not be suppressed. Comparative Example 3 In Comparative Example 2, Table 2 shows the composition and weight of the top liquid and kettle liquid after the orthoxylene recovery column was operated for 5 days.
The mass variation of 5- (O-tolyl) -2-pentene increased. Concentration of the alkali metal catalyst occurred in the distillation column, and it was not possible to purify the 5- (O-tolyl) -2-pentene with a high recovery rate by reducing the variable mass of 5- (O-tolyl) -2-pentene only by operating the distillation column. Comparative Example 4 In Comparative Example 2, the orthoxylene recovery column was further operated for 10 days, but precipitation of solids occurred in the vicinity of the distillation column feed stage, making it difficult to feed the product liquid, and the operation was stopped.

[0024]

[Table 1] ───────────────────────────── Orthoxylene 81.87 wt% OTP-2 16.10 wt% OTP-30 0.003 wt% OTP-4 0.016 wt% C20H 0.071 wt% Other high boiling by-products 2.03 wt% ────────────────────────── ----- OTP-2; 5- (O-tolyl) -2-pentene. OTP-3; 5- (O-tolyl) -3-pentene. OTP-4; 5- (O-tolyl) -4-pentene. C20H; 5- (O-tolyl) -2-pentene, a compound having a molecular weight of 266 produced by the reaction of ortho-xylene.

[0025]

[Table 2] ─────────────────────────────────── Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 ──────────────────────────────────── Overhead liquid Weight kg / hr 8.19 8.28 8.21 8.31 Composition wt% Ortho-xylene 99.99 99.99 99.99 99.99 OTP-2 0.001 0.001 0.001 0.001 Kettle discharge weight kg / hr 1.81 1. 72 1.79 1.69 Composition wt% Orthoxylene 0.001 0.001 0.001 0.001 OTP-2 88.36 71.46 85.43 60.45 OTP-3 0.015 0.71 0. 14 0.83 OTP-4 0.088 4.73 0.95 6.28 C20H 0.39 2.670 .53 4.06 Other high boiling by-products 11.15 20.42 12.95 28.38 ───────────────────────────── ──────── OTP-2; 5- (O-tolyl) -2-pentene. OTP-3; 5- (O-tolyl) -3-pentene. OTP-4; 5- (O-tolyl) -4-pentene. C20H; 5- (O-tolyl) -2-pentene, a compound having a molecular weight of 266 produced by the reaction of ortho-xylene.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Takakawa 22 Wadai, Tsukuba City, Ibaraki Prefecture Mitsubishi Gas Chemical Co., Ltd.

Claims (9)

[Claims] 1. A side chain of an aromatic hydrocarbon compound in which one or more hydrogen atoms are bonded to the α-position of the side chain is alkenyl with an alkali metal-based supported catalyst using a conjugated diene having 4 or 5 carbon atoms. In the production of monoalkenylbenzenes, the monoalkenylbenzenes are separated and collected by distillation after deactivating and / or removing the alkali metal-based supported catalyst in the reaction product solution. Purification methods. 2. The method according to claim 1, wherein the reaction product solution is filtered using a filter having a size of 5 μm or less to remove the alkali metal-based supported catalyst. 3. The method according to claim 1, wherein the alkali metal-based supported catalyst is deactivated and / or removed by contacting with a solid acid. 4. The method according to claim 1, wherein the alkali metal-based supported catalyst is deactivated and / or removed by contacting with a carbon material. 5. The method according to claim 1, wherein the alkali metal-based supported catalyst is deactivated and / or removed by bringing it into contact with a cationic ion exchange resin. 6. A compound obtained by calcining a mixture of potassium hydroxide and alumina hydrate at 350 to 700 ° C. is heat treated by adding metallic sodium at 100 to 300 ° C. under an inert gas. The method according to claim 1, wherein the resulting mixture is used as a catalyst. 7. A mixture obtained by heat treating a compound obtained by calcining a mixture of a basic potassium compound and alumina at 350 to 700 ° C. at 100 to 300 ° C. in an inert gas, and heat treating the mixture. The method according to claim 1, which is used as a catalyst. 8. The method according to claim 1, wherein the catalyst is a mixture obtained by heat-treating an alkaline earth metal oxide containing a potassium compound and metallic sodium under an inert gas. 9. The method according to claim 1, wherein a mixture obtained by heat-treating zirconium oxide containing a potassium compound and metallic sodium under an inert gas is used as a catalyst.