JP2921546B2 - 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 in which one or more hydrogen atoms are bonded to the α-position of a side chain by using a conjugated diene having 4 or 5 carbon atoms. The present invention relates to a method for producing monoalkenylbenzenes by alkenylation with a metal catalyst and then purifying the monoalkenylbenzenes from a reaction product solution. Monoalkenylbenzenes are useful as intermediate raw materials for various organic compounds such as high molecular monomers and pharmaceuticals. For example, 5- (O-tolyl)-produced from O-xylene and 1,3-butadiene After ring closure, 2-pentene can be converted to industrially useful 2,6-naphthalenedicarboxylic acid by dehydrogenation, isomerization and oxidation.

[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, and you'll separated and recovered monoalkenyl benzene by distillation, recovery of a high purity to occur degradation of the mono alkenyl benzenes and higher mono alkenyl benzene It is known that it cannot be obtained.

[0003] Therefore to prevent problems such as described above, in JP 51 over 4127, the total concentration of alkali metal and organic alkali metal compound in the hydrocarbon to distillation feed, the hydrocarbon phase 1kg per alkali metal component Proposals have been made to range from 0.09 to 15 milligram atoms.
However, in this method, not all of the alkali metal catalyst component is removed, and 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 directly introduced into the distillation column, monoalkenylbenzenes further react with unreacted alkylbenzenes and monoalkenylbenzenes themselves to form high molecular weight by-products in the presence of an active catalyst. It returns to the starting material alkylbenzenes by the reverse reaction, or produces the desired isomer other than monoalkenylbenzene by the transfer of the double bond. That is, reducing 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. 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, it becomes impossible to obtain high-purity monoalkenylbenzenes, and the recovery rate decreases. I will. This alteration of monoalkenyl benzene can be suppressed to some extent by lowering the distillation temperature.For this purpose, it is necessary to carry out distillation under reduced pressure, so that the alteration of monoalkenyl benzene does not occur at all. This requires a high vacuum, and 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. And
When unreacted aromatic hydrocarbons are distilled off in the distillation, alkali salts having a solubility or higher are precipitated as solids and accumulated in 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 cannot be operated stably to obtain high-purity monoalkenylbenzenes.

Further, 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 rendered water-soluble, followed by separation. However, in this method, when the reaction product liquid is brought into contact with water, there is a risk of generating a large amount of reaction heat and firing. The reaction can be controlled to some extent by the amount of water and reaction solution to be brought into contact, and the addition time. This is not a typical method. In USP 3,244,758, addition of isopropanol before distillation to inactivate an alkali metal or an alkali metal compound contained in a product solution prevents an undesirable side reaction from occurring during distillation. I'm preventing. However, this method can avoid the risk 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 alkyl alcoholate soluble in an organic solvent, This is not preferable because of the above-mentioned problems.

[0006]

SUMMARY OF THE INVENTION The present inventors initially thought that
The reaction product was allowed to stand and separated by filtration into a catalyst and a liquid phase containing the target substance, and the liquid phase was distilled to purify the monoalkenyl benzenes, and tried to separate and recover them.
In the distillation step, the intended monoalkenylbenzenes were altered in quality, and monoalkenylbenzenes could not be obtained with high purity and high recovery. In addition, accumulation of insoluble compounds also occurs in the distillation column, and the distillation efficiency of the target product decreases,
In addition, the distillation column was clogged and the distillation operation could not be performed. That is, the reaction product liquid was allowed to stand, and filtration was performed to separate the catalyst and the liquid phase containing the target substance.However, it was not possible to completely remove the particulate catalyst by filtration alone, and a part of the alkali metal was soluble. Was found to be mixed into the liquid phase as an 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. For this reason, it has been found that high-purity monoalkenylbenzenes cannot be obtained, and that the recovery rate also decreases.

The alteration of the monoalkenyl benzene can be suppressed to some extent by lowering the distillation temperature. For this purpose, it is necessary to carry out the distillation under reduced pressure, and the alteration of the monoalkenyl benzene does not occur at all. This requires a high vacuum, which makes the equipment and operation costs industrially high and impractical. A part of the alkali metal is also introduced into the distillation column as an alkali salt soluble in an organic solvent, and when an unreacted aromatic hydrocarbon is distilled off in the distillation, the alkali salt having a solubility higher than the solubility is precipitated as a solid and distilled. It accumulates inside the tower. 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, it was found that this problem could not be avoided only by the distillation operating conditions. 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. A process for producing monoalkenylbenzenes by alkenylation with an alkali metal catalyst to produce monoalkenylbenzenes from the reaction product with high purity and high recovery.

[0008]

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 the method of producing and separating and recovering monoalkenylbenzenes from the reaction product solution, the reaction product solution was converted to a solid acid or carbon material.
Material or contact with a cationic ion exchange resin
Deactivates potassium metal catalyst and removes alkali metal catalyst
After that , 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 provides one or more hydrogen atoms at the α-position of the side chain.
A carbon atom is attached to the side chain of an aromatic hydrocarbon compound
Alkali metal catalyst using conjugated dienes of formula 4 or 5
To produce monoalkenyl benzenes
(1) Solid acid, carbon material
Material selected from solid materials and cationic ion exchange resins
The alkali metal catalyst is brought into contact with the solid
(2) Fill the reaction solution with a
Filtration using a filter to remove the alkali metal catalyst.
And then separate and collect monoalkenylbenzenes by distillation
Purification of monoalkenylbenzenes
Is the law . In the present invention, the reaction product liquid is distilled.
Before separating and recovering monoalkenylbenzenes, alkali
Deactivation operation of metal catalyst and filter of 5 microns or less
The filtration operation is carried out using the deactivation operation and the filtration operation in this order.
The order is not limited.

Hereinafter, the method of 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. As monocyclic aromatic hydrocarbons,
Monoalkylbenzenes such as toluene, ethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, sec-butylbenzene, isobutylbenzene, o-, m-, p-xylene, o-, m-, p
Dialkylbenzenes such as -ethyltoluene, o-, m- and p-diethylbenzene; trialkylbenzenes such as mesitylene and pseudocumene; 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene And polyalkylbenzenes such as pentamethylbenzene and hexamethylbenzene, and polycyclic aromatic hydrocarbons such as 1- and 2-methylnaphthalene, dimethylnaphthalene, tetrahydronaphthalene and indane. As one of the raw materials, conjugated dienes having 4 or 5 carbon atoms include 1,3-butadiene, 1,3-pentadiene, and isoprene.

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. A variety of reaction systems can be used to use these catalysts in the reaction. In general, monoalkylbenzene is a method in which aromatic hydrocarbons, one of the raw materials, are present in excess relative to conjugated dienes. Selectivity to the class 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.
5 atm, preferably in the range of 0.1 to 2 atm. The ratio of the conjugated diene having 4 or 5 carbon atoms to the starting aromatic hydrocarbon in the method of the present invention is in the range of 0.01 to 1, preferably 0.03 to 0.5 in molar ratio. If the amount of diene is larger than this, the produced monoalkenylbenzene further reacts with the diene, so that one molecule of aromatic hydrocarbon contains two diene.
It is not preferable because the formation of a compound having more than one molecule added increases, and the polymerization of diene is apt to occur and the selectivity decreases.
The amount of the catalyst used in the method of the present invention is at least 0.01% by weight, preferably 0.1% by weight, based on the starting aromatic hydrocarbon.
It is at least 05%.

The method of the present invention employs a reaction system such as a batch system, a semi-batch system, and a completely mixed circulation system. The reaction time of the batch system, the semi-batch system or the residence time of the completely mixed circulation system is 0.1. -10 hours are employed. When performing the reaction by suspending the catalyst, usually after the reaction,
The product is allowed to settle and most of the catalyst first settles. Next, the product liquid is withdrawn from the reaction tank. At this time, as one method, first, a large amount of the alkali metal catalyst is removed by filtration using a filter of 5 μm or less. Some of the particulate catalyst when using a coarse filter of no more eyes undesirable cause deterioration of mono alkenyl Ben <br/> Zen in the distillation step included in the recovered product solution. Even when the alkali metal catalyst is removed by filtration using a filter of 5 μm or less, a 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 directly introduced into the distillation column, the conversion of monoalkenylbenzene is caused by the active soluble catalyst. 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 liquid containing the particulate insoluble alkali metal catalyst solid and the soluble alkyl or alkenyl complex or alkali salt, and then inactivate using a filter of 5 μm or less. This is a method of filtering and removing the activated alkali metal catalyst. Either of the above methods can be used, but when the first method is used, the active alkali metal catalyst collected on the filter induces alteration of monoalkenyl benzene on the filter and causes An alkenylbenzene polymer is formed, which may cause filter clogging. Therefore, the latter method is more preferably used.

In order to deactivate and / or remove the catalyst, a method of contacting with a solid acid or carbon material or a cationic ion exchange resin is preferred. This method can control the generation of a large amount of reaction heat, does not cause a danger of ignition, and can remove all of the alkali metal components, so that the distillation column can be operated for a long period of time, the operation method is simple, and the industrial scale is simple. It can be said that this method is easy to carry out. When a solid acid is used, the alkali metal component in the alkali metal catalyst active by the acid-base reaction is adsorbed on the solid acid and can be deactivated and / or removed. Solid acids that can be used include activated clay, alumina,
There are silica-alumina and various zeolites. When zeolite is used, a hydrogen ion exchange type zeolite is particularly preferably used, and mordenite, Y type, X type, Z type
There is no particular limitation on the type of zeolite such as SM type and ferrierite. When a carbon material is used, the alkali metal component in the active alkali metal catalyst is adsorbed on a functional group such as a surface hydroxyl group or a carboxylic acid group, or is absorbed into the carbon material by an intercalation mechanism. It can be deactivated and / or removed. As the carbon materials that can be used, applied graphite, activated carbon, Amo Le amorphous carbon obtained by calcining petroleum and coal-based pitch is not particularly limited such as PAN-based carbon fibers, fired as necessary, the oxide, carbide degree , Surface functional groups and surface area can be adjusted for use. When using a cationic ion exchange resin,
The alkali metal component in the alkali metal catalyst active by the acid-base reaction can be deactivated and / or removed by being adsorbed on the functional group on the cationic ion exchange resin. Examples of the cationic ion exchange resin that can be used include a sulfonic acid type and a carboxylic acid type, and an ion exchange resin having a higher degree of crosslinking than the swelling resistance to an organic solvent is preferable.

When contacting these solids with the product liquid,
If there is a risk of generating a large amount of reaction heat or ignition at the time of deactivation of the alkali metal catalyst, the deactivation reaction can be appropriately controlled by adjusting the introduction rate of the solid or the product solution. Also,
A gas such as a mixed gas having an oxygen concentration of 20% or less diluted with an inert gas, steam, a mixed gas of a carbon dioxide and an oxygen concentration of 20% or less, or a gas mixture of a carbon dioxide and a steam.
A liquid such as water, an aqueous acid, or an alcohol is brought into contact with the product liquid to deactivate the active alkali metal catalyst to some extent, and then these solids are brought into contact with the product liquid to completely deactivate the alkali metal catalyst. Alternatively, a removing method can be adopted.
The contact time may be a time sufficient to deactivate and / or remove the active alkali metal catalyst. The contact temperature can be selected from a wide range of room temperature to the boiling point of the starting aromatic hydrocarbon, but room temperature is sufficient. Batch method as contact method,
A reaction system such as a semi-batch system, a completely mixed circulation system, or a fixed bed circulation system is employed, but any system can be used as long as solid-liquid contact is sufficient. The amount of the solid used may be an amount sufficient to remove the alkali metal component.

[0015]

As described above, when alkenylbenzene is separated and recovered by distillation from the alkenylbenzene product liquid in which the alkali metal catalyst has been deactivated and / or removed, no alteration occurs even by atmospheric distillation, and high purity is obtained. Alkenylbenzene can be obtained at a high recovery rate, the distillation column can be operated stably, and its industrial significance is extremely large.

[0016]

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 had no oxygen and water, and then 100 kg of O-xylene dehydrated using a molecular sieve was added in a nitrogen stream to give 140 ° C. Heated to C. 1,3-Butadiene 7.0 with stirring under normal pressure
kg was introduced for 1 hour and reacted. After the reaction, stirring was stopped, the mixture was allowed to stand, the temperature was lowered, and the product liquid was extracted. A part of this product liquid was taken and analyzed by gas chromatography. The results are shown in Table 1. 5- (O-
Tolyl) -2-pentene selectivity was 83.0%.
The reaction product is passed through a fixed bed column filled with activated clay to completely adsorb and deactivate the alkali metal catalyst. After that, the reaction product is further filtered with a stainless sintered metal filter having a pore diameter of 1 micron. Through. This product liquid was introduced into the orthoxylene recovery tower at a rate of 10 kg / hr. Table 2 shows the composition and weight of the top liquid and the outlet liquid when the orthoxylene recovery tower was operated at a normal temperature and a kettle temperature of 230 ° C. 5- (O-
No alteration of (tolyl) -2-pentene was observed.
Next, the 5- (O-tolyl) -2-pentene purification tower was operated under normal pressure at a kettle temperature of 250 ° C., and 5- (O-tolyl) -2-pentene was recovered from the top of the tower. Purity 99.8%
And the recovery was 98.5%.

Example 2 The procedure of Example 1 was repeated, except that the operations of adsorbing and deactivating and removing the alkali metal catalyst were performed using hydrogen ion type mordenite. The purity of 5- (O-tolyl) -2-pentene was 99.7%, and the recovery was 98.4%. Example 3 The same operation as in Example 1 was carried out except that the operations for adsorbing, occluding and deactivating and removing the alkali metal catalyst were performed with activated carbon. The purity of 5- (O-tolyl) -2-pentene is 99.
6%, and the recovery was 98.4%.

Example 4 Example 1 was repeated except that the operations of adsorbing, occluding, and deactivating and removing the alkali metal catalyst were performed using graphite.
The same was done. The purity of 5- (O-tolyl) -2-pentene was 99.6% and the recovery was 98.8%. Example 5 The same operation as in Example 1 was performed except that the operations for adsorption and deactivation removal of the alkali metal catalyst were performed using a sulfonic acid ion exchange resin (Amberlyst 15). The purity of 5- (O-tolyl) -2-pentene was 99.6% and the recovery was 98.9%.

Comparative Example 1 The product liquid obtained after the alkenylation reaction in Example 1 was allowed to stand.
Removed after cooling. 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 outlet liquid when the orthoxylene recovery tower was operated at a normal temperature and a kettle temperature of 230 ° C. 5- (O) in the bottom product of the target product
-Tolyl) -2-pentene is deteriorated, and 5
The amount of-(O-tolyl) -2-pentene was significantly reduced and 5
High boiling components by the reaction of-(O-tolyl) -2-pentene with ortho-xylene, increase of ortho-xylene by reverse reaction of alkenylation reaction, transfer of double bond of 5- (O-tolyl) -2-pentene Formation of the isomers 5- (O-tolyl) -3-pentene and 5- (O-tolyl) -4-pentene was observed.

Comparative Example 2 The product solution after the alkenylation reaction in Example 1 was allowed to stand.
After cooling, the reaction product was extracted through a stainless sintered metal filter having a pore diameter of 1 micron. This product liquid is used as it is without deactivating the alkali metal catalyst component.
It was introduced at a rate of 10 kg / hr into an orthoxylene recovery tower operated under a reduced pressure of mmHg and a kettle temperature of 120 ° C. 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- (O-tolyl)
Although the variable mass of -2-pentene was reduced, by-products 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. 5
The variable mass of-(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 feed column of the distillation column, and the supply of the product liquid became difficult, so the operation was stopped.

[0021]

[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 produced by reacting 5- (O-tolyl) -2-pentene with orthoxylene.

[0022]

[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 produced 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) JP-A-49-70929 (JP, A) US Patent 3,244,758 (US , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 15/44 B01J 39/04 C07C 2/66

Claims (2)

(57) [Claims] 1. The alkenylation of an aromatic hydrocarbon compound having at least one hydrogen atom at the α-position of the side chain with an alkali metal catalyst using a conjugated diene having 4 or 5 carbon atoms. In producing monoalkenyl benzenes by the reaction, (1) solid acid, carbon material, cationic
Contact with one or more solids selected from ion exchange resins
Deactivation of alkali metal catalysts and (2) reaction
The product liquid is filtered using a filter of 5 microns or less,
A method for purifying monoalkenylbenzenes , comprising removing the alkali metal 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 .