JP2921544B2 - Purification method of monoalkenylbenzenes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an aromatic hydrocarbon compound having at least one hydrogen atom bonded to the α-position of a side chain in the presence of an alkali metal catalyst. And alkenylation using the conjugated dienes to produce monoalkenylbenzenes, and then purify and obtain the monoalkenylbenzenes from a reaction product liquid. Monoalkenylbenzenes are useful as intermediate raw materials for various organic compounds such as polymer monomers and pharmaceuticals, and for example, 5- (O-tolyl) -2 produced from O-xylene and 1,3-butadiene. -Pentene is converted to industrially useful 2,6-naphthalenedicarboxylic acid by dehydrogenation, isomerization and oxidation after ring closure.

[0002]

2. Description of the Related Art Catalysts for producing monoalkenylbenzenes by alkenylating the side chains of aromatic hydrocarbon compounds with conjugated dienes having 4 or 5 carbon atoms include alkali metals such as sodium, potassium and the like. A method using an alloy of, a carrier obtained by calcining a mixture of a basic potassium compound and alumina, under an inert gas, a method using a mixture obtained by heat treatment by adding sodium metal,
There is known a method in which a metal sodium or a metal potassium is supported on an alkali metal oxide or an alkaline earth metal oxide. Among these catalysts, alkali metals such as sodium and potassium and their alloys are used to separate and recover monoalkenylbenzenes from the obtained reaction product. , by decantation or filtration to separate into liquid phase containing the catalyst and desired product, in the case of separating and recovering the monoalkenyl benzene by distillation, recovery of high mono alkenyl benzene in high purity occur alteration of mono alkenyl benzenes It is known that it cannot be obtained.

In order to prevent the above-mentioned problems, Japanese Patent Application Laid-Open No. 51-4127 discloses that the total concentration of an alkali metal and an organic alkali metal compound in a hydrocarbon used as a distillation raw material is determined based on the alkali metal component per kg of the hydrocarbon phase. Proposals have been made for the range of 0.09-15 milligram atoms. However, in this method, not all of the alkali metal catalyst component is removed, and a part of the alkali metal catalyst component is mixed into the liquid phase as a soluble alkyl or alkenyl complex. When this product liquid is introduced into the distillation column as it is, monoalkenylbenzenes further react with unreacted alkylbenzenes and monoalkenylbenzenes themselves in the presence of an active catalyst to produce high molecular weight by-products, A reverse reaction returns to the starting material alkylbenzenes, or the transfer of a double bond produces an isomer other than the desired monoalkenylbenzene. Decreasing the total concentration of the alkali metal and the organic alkali metal compound only lowers the degree, and cannot prevent the deterioration at all. In addition, when the distillation column is operated for a long period of time, a small amount of alkali metal and organic alkali metal compound is concentrated in the distillation column, and eventually, high-purity monoalkenylbenzenes cannot be obtained, and the recovery rate also decreases. . This alteration of monoalkenyl benzene can be suppressed to some extent by lowering the distillation temperature, but for that purpose, it is necessary to carry out distillation under reduced pressure, so that the alteration of monoalkenyl benzene does not occur at all. Requires a high vacuum, and the equipment and operation costs are industrially high, which is not practical.

Japanese Patent Application Laid-Open No. 49-70929 discloses a method of separating and removing a catalyst from a reaction product solution and treating it with carbon dioxide for distillation, or treating a reaction product solution with carbon dioxide and separating and removing the catalyst for distillation. Has been proposed. In this method, the alkali metal and the organic alkali metal compound are completely deactivated by the carbon dioxide treatment, and the deterioration of the monoalkenyl benzene can be prevented in the distillation, but the generated alkali carbonate such as alkali carbonate and alkali carboxylate can be prevented. Is soluble in the organic solvent and introduced into the distillation column. When unreacted aromatic hydrocarbons are distilled off in the distillation, alkali salts having a solubility higher than the solubility precipitate as solids and accumulate inside the distillation column. Therefore, not only the gas-liquid contact in the distillation column is reduced and the distillation efficiency is reduced, but also the distillation column is finally clogged and the distillation operation cannot be performed.
That is, unless the alkali metal component is completely removed, the distillation column is operated stably, and it becomes impossible to obtain high-purity monoalkenylbenzenes.

Japanese Patent Publication No. 57-26489 proposes a method in which alkenylbenzene is brought into contact with water, the water is adjusted to pH 6 or less, and the alkali metal catalyst is made water-soluble, followed by separation. However, in this method, when the reaction product solution is brought into contact with water, there is a danger of generating a large amount of reaction heat or firing. The reaction can be controlled to some extent by the amount of water or reaction product solution to be brought into contact, and the addition time.However, when it is attempted to carry out the reaction on an industrial scale, a long processing time is required and the equipment becomes large-scale. Not a realistic method. In US Pat. No. 3,244,758, an undesired side reaction during distillation is prevented by adding isopropanol before distillation to inactivate an alkali metal or an alkali metal compound contained in a product solution. In. However, this method can avoid the danger of generating a large amount of reaction heat or ignition 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, The above-described problem is caused, which is not preferable.

[0006]

As described above, in the prior art, it is necessary to separate and recover monoalkenylbenzenes from a reaction product solution with a high purity and a high recovery rate, and to operate the distillation column stably for a long time. And cannot be safely implemented on an industrial scale. In view of the above, an object of the present invention is to use a conjugated diene having 4 or 5 carbon atoms for the side chain of an aromatic hydrocarbon compound having one or more hydrogen atoms bonded to the α-position of the side chain. In the production of monoalkenyl benzenes by alkenylation with an alkali metal catalyst to produce monoalkenyl benzenes from the reaction solution, the distillation column is operated stably for a long time with high purity and high recovery, and industrially safe. An object of the present invention is to provide a method for separating and recovering on a scale.

[0007]

Means for Solving the Problems The present inventors have alkenylated an aromatic hydrocarbon compound at the α-position with a supported alkali metal catalyst using a conjugated diene having 4 or 5 carbon atoms to convert monoalkenylbenzenes. As a result of intensive studies on a method for producing and separating and recovering monoalkenylbenzenes from the reaction product solution, the reaction product solution was brought into contact with alcohol.
Touch, and further with water and / or acid aqueous solution, or solid acid or carbon
For contact of materials or cationic ion exchange resins with solids
Deactivated alkali metal catalyst
After removing the medium, the inventors have found that monoalkenylbenzenes can be purified with high purity and high recovery rate by separating and recovering monoalkenylbenzenes by distillation, and the present invention has been completed. That is, the present invention relates to an alkali metal catalyst.
In the presence of at least one hydrogen atom bonded to the α-position of the side chain
The aromatic hydrocarbon compound has a side chain of 4 or 5 carbon atoms.
Alkenylation using a diene
When producing carrots, the reaction product
Contact with coal, and then with water and / or acid aqueous solution, or
Or solid acid, carbon material or cationic ion exchange resin
Deactivation of the alkali metal catalyst by contact
(2) Filter the reaction product using a filter of 5 microns or less.
This is a method for purifying monoalkenylbenzenes , which comprises filtering, removing an alkali metal catalyst , and separating and recovering monoalkenylbenzenes by distillation. What
In the present invention, a monoalkenyl is distilled from a reaction product liquid.
Before the separation and recovery of
Inactivation operation and filtration operation using a filter of 5 microns or less
Operation, but the order of this deactivation operation and filtration operation is limited.
Absent.

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

The alkali metal catalyst used in the present invention includes sodium metal, potassium metal, and an alloy of sodium and potassium metal. Further, in order to increase the specific gravity of these alkali metals, other elements may be added and used. In using these catalysts in the reaction, various reaction systems are employed. In general, a method in which an aromatic hydrocarbon, which is one of the raw materials, is present in excess with respect to the conjugated diene is used. The selectivity to alkylbenzenes can be improved. For this purpose, a method of continuously supplying conjugated dienes to the reaction system by a semi-batch method is preferable. When the reaction is performed continuously in a complete mixing system, the reactor is divided into multiple stages, and conjugated dienes are supplied to each stage. It is preferable to employ the method because a high selectivity can be obtained.

The reaction temperature in the method of the present invention is 100 to 2
It is in the range of 00 ° C. If it is lower than this, the reaction occurs, 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 are increased, which is not preferable. In the present invention, the reaction is carried out under the condition that the starting aromatic hydrocarbon and the product are in a substantially liquid state. The reaction pressure is not particularly limited as long as the raw material aromatic hydrocarbon and the product are substantially in a liquid state, and is not particularly limited. The reaction pressure is 0.05 to 5 atm in absolute pressure, preferably 0.1 to 5 atm. It is in the range of 1-2 atm. In the method of the present invention, the ratio of the conjugated diene having 4 or 5 carbon atoms as one raw material to the raw aromatic hydrocarbon is generally in the range of 0.01 to 1, preferably 0.03 to 0.5 in molar ratio. It is. When the amount of diene is larger than this, the generated monoalkenylbenzene further reacts with the diene to increase the production of a compound in which two or more molecules of diene are added to one molecule of aromatic hydrocarbon, and polymerization of the diene is likely to occur. It is not preferable because the rate decreases. The amount of the catalyst used in the method of the present invention is 0.01% by weight based on the amount of the starting aromatic hydrocarbon.
Or more, preferably 0.05% or more.

In the method of the present invention, a reaction system such as a batch system, a semi-batch system, and a complete mixed circulation system is employed. The reaction time in the batch system, the semi-batch system or the residence time in the complete mixed circulation system is 0.1. -10 hours are employed. When the reaction is carried out by suspending the catalyst, usually, after the reaction, the product liquid is allowed to stand and most of the catalyst is first settled. Next, the product liquid is withdrawn from the reaction tank. At this time, as one method, first, filtration is performed using a filter of 5 μm or less to remove most of the alkali metal catalyst. If a coarser filter is used, a part of the fine-particle catalyst is contained in the recovered product liquid, and monoalkenylbenzene is deteriorated in the distillation step, which is not preferable. Even if the alkali metal catalyst is removed by filtration using a filter of 5 μm or less, part of the alkali metal is mixed into the liquid phase as a soluble alkyl or alkenyl complex or alkali salt. When this product liquid is introduced into the distillation column as it is, the active soluble catalyst causes the alteration of monoalkenylbenzene. Although the amount of the soluble catalyst is not large, the quality of the monoalkenylbenzene increases to a considerable extent when it is concentrated in the distillation column retentate and operated for a long period of time. Therefore, the active soluble catalyst needs to be deactivated before the product liquid is introduced into the distillation column. The other is to first deactivate the alkali metal catalyst component from the product solution containing the particulate insoluble alkali metal catalyst and soluble alkyl or alkenyl complex or alkali salt, then deactivate using a filter of 5 microns or less. This is a method of removing the filtered alkali metal catalyst by filtration. Any of the above methods can be used, but when the first method is used,
The active alkali metal catalyst collected on the filter may alter the monoalkenylbenzene on the filter to produce a high molecular weight monoalkenylbenzene polymer, which may cause clogging of the filter. Therefore,
The latter method is more preferably used.

In order to deactivate the catalyst, it is necessary to first contact the alcohol with the product liquid to convert the active alkali metal catalyst into an alkali alcoholate in advance. When water or an acid aqueous solution is first used to deactivate the catalyst, there is a risk of generating a large amount of reaction heat and firing as described above, which is not preferable.
The alcohol that can be used is not particularly limited as long as it has a large difference in boiling point from the target monoalkenylbenzene, and methanol, ethanol, propanol, isopropanol, normal butanol, sec-butanol, ter-butanol and the like are preferably used. used. Particularly, alcohols such as isopropanol and ter-butanol are preferable in terms of reactivity and safety.

The contact temperature for deactivating the catalyst can be selected from a wide range from room temperature to the boiling point of the starting aromatic hydrocarbon, but room temperature is sufficient. The contact time may be a time sufficient to deactivate the active alkali metal catalyst. As a contact system, a reaction system such as a batch system, a semi-batch system, a complete mixing and circulation system, and the like are adopted. However, any system can be used as long as the liquid-liquid contact is sufficient. The amount of alcohol used is not particularly limited, but may be any amount that is sufficient to deactivate the active alkali metal catalyst in the product solution. Upon contact with the alcohol, the active alkali metal catalyst becomes an alkali alcoholate. Among them, the alkali alcoholate having a solubility or higher is precipitated as a solid. This solid is removed from the product solution using a filter, but the soluble alkali alcoholate still exists in the product solution.
If the product liquid containing the alkali metal component is introduced into the distillation column as it is, if the unreacted aromatic hydrocarbons are distilled off in the distillation, the alkali alcoholate having a solubility higher than the solubility will precipitate as a solid and accumulate inside the distillation column. Will come. Therefore, not only the gas-liquid contact in the distillation column is reduced and the distillation efficiency is reduced, but also the distillation column is finally clogged and the distillation operation cannot be performed. Therefore, in order to stably operate the distillation column and obtain high-purity monoalkenylbenzenes, it is necessary to completely remove the alkali metal component.

In order to remove the alkali metal component, water, a liquid such as an aqueous acid solution, and / or a solid acid, a carbon material,
It is preferable to make contact with a solid such as a cationic ion exchange resin. The aqueous acid solution is not particularly limited, and inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, butyric acid, and benzoic acid can be used. When the acid aqueous solution and the product liquid are brought into contact with each other, the alkali metal component can be separated into two layers from the product liquid as an aqueous solution of an alkali salt and separated into an aqueous layer. The amount of the aqueous acid solution used may be an amount sufficient to remove the alkali metal component. In the case where a dry acid or an organic acid itself soluble in an organic solvent is added without contacting with an aqueous acid solution, when excess acid remains in the product solution, monoalkenylbenzene causes a side reaction with the acid catalyst in the distillation step, which is preferable. Absent. When water and the product liquid are brought into contact, the alkali metal component present as an alkali alcoholate can be separated into two layers with the product liquid as an aqueous alkali hydroxide solution and separated into an aqueous layer.
The amount of water used may be an amount sufficient to remove the alkali metal component. The alkali metal component can be separated into two layers from the product solution as an aqueous alkali hydroxide solution and separated into an aqueous layer.
The contact time with these liquids is not particularly limited, and may be any time long enough to remove the alkali metal component. The contact temperature can be selected from a wide range from room temperature to the boiling point of the starting aromatic hydrocarbon, but room temperature is sufficient. As a contact system, a reaction system such as a batch system, a semi-batch system, and a complete mixing and distribution system is adopted. However, any system can be used as long as the liquid-liquid contact is sufficient.

A method of contacting with a solid such as a solid acid or a carbon material or a cationic ion exchange resin will be described below. When a solid acid is used, the alkali metal component can be adsorbed on the solid acid and removed by the acid-base reaction. Examples of solid acids that can be used include activated clay, alumina, silica-alumina, and various zeolites. When a zeolite is used, a hydrogen ion exchange type zeolite is particularly preferably used, for example, mordenite, Y-type, X-type, Z-type.
SM type, ferrierite, zeolite and the like are used. When a carbon material is used, the alkali metal component can be removed by being adsorbed by a functional group such as a surface hydroxyl group or a carboxylic acid group, or by being occluded in the carbon material by an intercalation mechanism. As the carbon materials that can be used, graphite, activated carbon, Amo Le amorphous carbon obtained by calcining petroleum and coal-based pitch, PA
There are no particular restrictions on N-based carbon fibers and the like, and firing and oxidation may be performed as necessary to adjust the degree of carbonization, surface functional groups, and surface area before use. When a cationic ion exchange resin is used, an alkali metal component can be adsorbed and removed by a functional group on the cationic ion exchange resin by an acid-base reaction. As the cationic ion exchange resin that can be used,
There are a sulfonic acid type and a carboxylic acid type, and an ion exchange resin having a higher degree of crosslinking than swelling property is preferable. The amount of the solid used is not particularly limited, but may be an amount sufficient to remove the alkali metal component. The contact time with these solids may be a time sufficient to remove the alkali metal component. The contact temperature can be selected in a wide range from room temperature to the boiling point of the starting aromatic hydrocarbon, but room temperature is sufficient.
As a contact method, a reaction method such as a batch method, a semi-batch method, a slurry complete mixing and flowing method, a fixed bed flowing method, and the like are adopted, but any method is sufficient if solid-liquid contact is sufficient.

[0016]

According to the present invention, when alkenylbenzene is separated and recovered by distillation from the alkenylbenzene-produced liquid from which the alkali metal catalyst has been deactivated and / or removed, no alteration occurs even at atmospheric pressure, and high purity alkenylbenzene is obtained. Its industrial significance is extremely high, such as obtaining a recovery rate and stably operating the distillation column.

[0017]

The method of the present invention will be described in detail below with reference to examples and comparative examples. Note that the present invention is not limited to the scope of the following embodiments.

Example 1 60 g of metallic sodium and 100 g of metallic potassium were charged into a stirred reactor which was replaced with nitrogen and substantially did not contain oxygen and water, and then dehydrated using a molecular sieve.
-Add 100 kg of xylene in a nitrogen stream,
Heated. Under normal pressure, while stirring, 7.0 kg of 1,3-butadiene was introduced for 1 hour to cause a reaction. After the reaction,
The stirring was stopped, the mixture was allowed to stand, the temperature was lowered, and the product liquid was discharged. A part of this product liquid was taken and analyzed by gas chromatography. The results are shown in Table 1. 5 based on 1,3-butadiene
-(O-tolyl) -2-pentene selectivity is 83.0%
Met. After isopropanol was added to the reaction product to completely deactivate the alkali metal catalyst, 2%
The aqueous layer was brought into contact with an aqueous hydrochloric acid solution to remove all the alkali metal components from the aqueous layer. The product liquid of the oil layer was introduced into the orthoxylene recovery tower at a rate of 10 kg / hr through a stainless steel sintered metal filter having a pore diameter of 1 micron. Table 2 shows the composition and weight of the top liquid and the bottom liquid when the orthoxylene recovery tower was operated at a normal temperature and a kettle temperature of 230 ° C. 5- (O-tolyl)-in the bottom product of the desired product
No alteration of 2-pentene was observed. Next, 5-
The (O-tolyl) -2-pentene purification tower was operated at a normal temperature and a kettle temperature of 250 ° C., and 5- (O-tolyl) -2 was obtained from the top of the tower.
-The pentene was recovered. Purity is 99.8%,
The recovery rate was 98.5%.

Example 2 Example 1 was repeated except that ter-butanol was added to completely deactivate the alkali metal catalyst, and then contacted with a 2% aqueous acetic acid solution to remove all the alkali metal components from the aqueous layer. Performed similarly. The purity of 5- (O-tolyl) -2-pentene was 99.7%, and the recovery was 98.4%. Example 3 Example 1 was repeated, except that isopropanol was added to completely deactivate the alkali metal catalyst, and then contacted with water to remove all of the alkali metal component from the aqueous layer.
The purity of 5- (O-tolyl) -2-pentene was 99.6%, and the recovery was 98.3%.

Example 4 Example 1 was repeated except that isopropanol was added to completely deactivate the alkali metal catalyst, followed by contact with activated clay to remove all the alkali metal components from the solid. . 5- (O-tolyl) -2-pentene purity is 9
It was 9.5% and the recovery was 98.5%. Example 5 The same procedure as in Example 1 was carried out except that ter-butanol was added to completely deactivate the alkali metal catalyst, and then further contacted with activated carbon to remove all of the alkali metal components from the solid. 5- (O-tolyl) -2-pentene purity is 9
It was 9.5% and the recovery was 98.5%. Example 6 The same as Example 1 except that isopropanol was added to completely deactivate the alkali metal catalyst, and then contacted with a sulfonic acid-based cation exchange resin to remove all of the alkali metal component on the solid. went. 5- (O-tolyl)-
The 2-pentene purity is 99.5% and the recovery is 98.
5%.

Comparative Example 1 In Example 1, the product solution after the alkenylation reaction was allowed to stand, and the temperature was lowered. This product liquid was directly introduced into the ortho-xylene recovery tower at a rate of 10 kg / hr without passing through a filter. Table 2 shows the composition and weight of the top liquid and the bottom liquid when the orthoxylene recovery tower was operated at a normal temperature and a kettle temperature of 230 ° C. The desired product, 5-
Deterioration of (O-tolyl) -2-pentene occurred, and the amount of 5- (O-tolyl) -2-pentene in the discharge from the kettle was remarkably reduced. 5- (O-tolyl) -2-pentene and ortho-xylene Further increased high-boiling components, increase of ortho-xylene by reverse reaction of alkenylation reaction, 5- (O-tolyl)-
5-isomer, which is an isomer due to the transfer of a double bond of 2-pentene
(O-tolyl) -3-pentene, 5- (O-tolyl)-
The formation of 4-pentene was observed.

Comparative Example 2 In Example 1, the product liquid after the alkenylation reaction was allowed to stand and cooled, and then the reaction product liquid was extracted through a stainless sintered metal filter having a pore diameter of 1 micron. This product liquid was introduced at a rate of 10 kg / hr into an orthoxylene recovery tower operated at a reduced pressure of 20 mmHg and a kettle temperature of 120 ° C. without deactivating the alkali metal catalyst component. Table 2 shows the composition and weight of the top liquid and the bottom liquid one day after the operation of the ortho-xylene recovery tower. 5-
Although the variable mass of (O-tolyl) -2-pentene was reduced, the by-product could not be suppressed. Comparative Example 3 Table 2 shows the composition and weight of the top liquid and the bottom liquid after operating the orthoxylene recovery tower for 5 days in Comparative Example 2. The variable mass 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 at a high recovery rate by reducing the variable mass of 5- (O-tolyl) -2-pentene only by operating conditions of the distillation column.

COMPARATIVE EXAMPLE 4 In Comparative Example 2, the orthoxylene recovery column was further operated for 10 days. However, solids precipitated near the distillation column feed stage, and the feed of the product liquid became difficult, so the operation was stopped. Comparative Example 5 In Example 1, after isopropanol was added to completely deactivate the alkali metal catalyst, the precipitated solid was filtered through a stainless sintered metal filter having a pore diameter of 1 micron. This product solution still contained an alkali alcoholate soluble in an organic solvent. Without removing all the alkali metal components from the product liquid,
It was introduced at a rate of 10 kg / hr into an orthoxylene recovery tower operated under a reduced pressure of 0 mmHg and a kettle temperature of 120 ° C. The orthoxylene recovery tower was operated for 10 days. However, solids precipitated near the feed column of the distillation column, and the operation of the distillation column was stopped because of difficulty in feeding the product liquid.

[0024]

[Table 1] キ シ Ortho-xylene 81.87 wt% OTP-2 16.10 wt% OTP-3 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; a compound having a molecular weight of 266 formed by reacting 5- (O-tolyl) -2-pentene with orthoxylene.

[0025]

[Table 2] Example 1 Comparative Example 1 Comparative Example 2 Comparison Example 3 塔 overhead liquid weight kg / hr 8.19 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 ───────────────────────── Discharge from kettle Weight kg / hr 1.81 1.72 1.79 1.69 Composition wt% ortho-xylene 0 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 TP-4 0.088 4.73 0.95 6.28 C20H 0.39 2.67 0.53 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; a compound having a molecular weight of 266 formed by reacting 5- (O-tolyl) -2-pentene with orthoxylene.

Continuation of the front page (56) References JP-A-5-112478 (JP, A) JP-A-51-26823 (JP, A) US Patent 3,244,758 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 15/44 B01J 23/04 C07C 2/72

Claims (2)

(57) [Claims] An aromatic hydrocarbon compound in which at least one hydrogen atom is bonded to the α-position of a side chain in the presence of an alkali metal catalyst, using a conjugated diene having 4 or 5 carbon atoms in the side chain of the aromatic hydrocarbon compound. In producing alkenylbenzenes by alkenylation, the reaction product solution is brought into contact with (1) alcohol, and
Contact with water and / or acid aqueous solution, or solid acid, carbon material
Or by contact with a cationic ion exchange resin
Deactivation of the alkali metal catalyst and (2) reaction mixture
Filter using a filter of Klon
A method for purifying monoalkenylbenzenes , comprising removing a system catalyst, separating and recovering the monoalkenylbenzenes by distillation. 2. The method according to claim 1, wherein the alkali metal catalyst is metal potassium, gold or gold.
2. The method according to claim 1, wherein the element is sodium or an alloy thereof.
A method for purifying monoalkenylbenzenes .