JPH05170675A - Production of monoalkneylbenzene and its derivative - Google Patents

Abstract

PURPOSE:To efficiently produce an alkenylbenzene and its derivative. CONSTITUTION:An alkylbenzene is alkenylated with a conjugated diene by using a catalyst comprising metal sodium and anhydrous potassium carbonate and by arranging plural independent reaction zones in series while circulating unreacted raw materials.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously and safely producing alkenylbenzene by reacting alkylbenzene and butadiene in the presence of an alkali metal. More specifically, for example, o-xylene and 1,3
-5- (o-tolyl) -pentene, which is an alkenylbenzene obtained by the reaction with butadiene, is cyclized to form dimethyltetralin, which is dehydrogenated to dimethylnaphthalene and then polymerized by oxidation. The present invention relates to a compound having a high industrial value which can be converted to naphthalene dicarboxylic acid useful as a raw material, and the present invention relates to a method for continuously and safely producing such a useful raw material.

[0002]

2. Description of the Related Art Conventionally, a method for producing a monoalkenylbenzene by reacting alkylbenzene and 1,3-butadiene in the presence of an alkali metal is known (see US Pat. No. 3,244,758). However,
The above method has a drawback in that a large amount of expensive metal potassium must be used. To solve this problem, metal potassium and sodium sodium are used as catalysts when 1,3-butadiene is blown into alkylbenzene for reaction. A method has been proposed in which, when used in combination, a small amount of expensive potassium metal can be used (see Japanese Patent Publication No. 56-34570, US Pat. No. 3,766,288, and US Pat. No. 3,953,535). However, all of these methods use a highly reactive sodium-potassium alloy, which is ignited only by contact with air, oxygen, and water, which is extremely dangerous for disaster prevention and safety. Disaster prevention equipment is required.

US Pat. No. 4,990,717 describes a method for producing monoalkenylbenzene by an evaporation reaction method using a fixed bed in which potassium carbonate or alumina is loaded with metal potassium. This method is also extremely dangerous in terms of disaster prevention and safety because it directly uses potassium metal, which is a major drawback as an industrial process.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to produce alkenylbenzene in a high yield without directly using expensive metal potassium which has a high risk of ignition. . Moreover, by reacting alkylbenzene with 1,3-butadiene in the presence of a catalyst having a high activity and a high selectivity for the alkenylation reaction, it is possible to produce a by-product that is difficult and complicated to separate from the target product. The object is to suppress the production of a high-purity target product, that is, alkenylbenzene, in a high yield. Further, it is an object to provide a method for producing an alkyltetralin by cyclizing the alkenylbenzene and a method for producing an alkylnaphthalene by dehydrogenating the alkyltetralin.

[0005]

According to the present invention, when a monoalkenylbenzene is produced by reacting an alkylbenzene with a conjugated diene, (A) a catalyst comprising sodium metal and potassium carbonate is used, and (B) an independent catalyst. A plurality of reaction zones are arranged in series, and a reaction device is connected between adjacent reaction zones so that the reaction solution can flow in a certain direction, and (C) the raw material alkylbenzene and the catalyst are used for at least the first reaction. (D) feed conjugated diene to at least two or more of the reaction zones, (E) keep at least one reaction zone in a boiling state, and (F) from the last reaction zone. A method for producing monoalkenylbenzene is characterized in that the reaction solution is taken out.

In the above (E), it is preferable that the evaporate is liquefied and recovered in the reaction zone, and the liquid in which the evaporate is recovered is refluxed to the reaction zone before the reaction zone where it is evaporated.

The raw material alkylbenzene used in the method of the present invention is an alkylbenzene having at least one or two methyl groups or ethyl groups in the benzene nucleus, and specific compounds include toluene, ethylbenzene, o-xylene and m.
-Xylene and p-xylene are mentioned. It is preferable to use each of these alkylbenzenes individually, and if a mixture is used, it becomes difficult to separate the target product from the alkenylbenzene which is a reaction product with high purity.

Further, it is preferable to dehydrate these starting alkylbenzenes and use them for the reaction. Examples of the dehydration method include adsorption separation using a suitable desiccant (for example, activated alumina, silica gel, molecular sieves, activated carbon, etc.), chilling separation, or a method of dehydrating by contacting with sodium metal in advance. The lower the water content in the raw material, the more preferable it is, and it is particularly preferable that the water content is not more than the measurement sensitivity of the Karl Fischer method, which is a usual water content measuring method, for example, several ppm or less.

The conjugated diene used in the method of the present invention is preferably one having 4 to 5 carbon atoms, that is, 1,3-butadiene and / or isoprene. Further, it is preferable that these conjugated dienes are dehydrated and used in the reaction. Examples of the dehydration method include adsorption separation using a suitable desiccant such as activated alumina, silica gel, molecular sieves, activated carbon, etc. or cryogenic separation. The lower the water content in 1,3-butadiene, the lower the water content, which is preferably several ppm or less.

The catalyst used in the reaction of the alkylbenzene with, for example, 1,3-butadiene in the process of the present invention is
It is a catalyst composed of metallic sodium and potassium carbonate. A catalyst in which sodium metal is dispersed and supported on potassium carbonate is preferable.

The higher the purity of metallic sodium, the better, but it does not matter if it contains a trace amount of calcium or magnesium. 90% or higher in purity, preferably 9
It is preferably 9.0% or more.

Examples of the potassium carbonate salt include potassium carbonate and potassium hydrogen carbonate. Particularly preferred is potassium carbonate, but sodium carbonate may be contained in an equivalent amount or less. The potassium carbonate salt preferably has a particle size of 150 μm or less, particularly preferably 1 to 50 μm. If it exceeds 150 μm, the potassium carbonate salt will stay in the reaction tank, making it difficult to discharge it out of the reaction system, which hinders continuous operation.

(Preparation of Catalyst) Although the catalyst of the method of the present invention can be prepared by coexisting potassium carbonate and metallic sodium in a dispersed manner, the effect of the present invention can be further enhanced by dispersing and supporting metallic sodium in potassium carbonate. be able to.

The amount of metallic sodium dispersed and supported on the potassium carbonate salt is preferably 1.0 part by weight or more and less than 100.0 parts by weight per 100 parts by weight of the potassium carbonate salt. More preferably, it may be 1.0 to 30 parts by weight. When the amount of the metal sodium dispersed and supported is less than 1.0 part by weight, the reaction activity is low and an excessive reaction tank or reaction time is required to obtain the desired monoalkenylbenzene, which is not preferable in terms of industrial efficiency. ..

On the other hand, the amount of the dispersed metal sodium supported is 1
If it is 00.0 parts by weight or more, a highly polymerized product is by-produced during the reaction to poison the catalyst.

The potassium carbonate salt used must be sufficiently dried, and is preferably calcined and dried at a high temperature of 200 to 500 ° C. to improve its activity as a carrier catalyst.

The preparation of the catalyst composed of metallic sodium and potassium carbonate salt used in the method of the present invention is carried out by oxygen,
A dry preparation method in which metallic sodium and potassium carbonate salt are mixed by stirring in an inert gas that does not contain water, or a wet preparation in which metallic sodium and potassium carbonate salt are mixed by stirring in raw material alkylbenzene that does not contain oxygen and water. Any of the methods may be used, and the dry preparation method is 10
The temperature is preferably 0 to 250 ° C., and the preparation temperature in the wet preparation method is preferably 100 to 250 ° C. if the boiling point of the starting alkylbenzene or the pressure system is adopted.

The method of stirring and mixing the metallic sodium and the potassium carbonate salt is not particularly limited, but a method using a stirrer having a rotary blade, a method using a homogenizer, a method using an ultrasonic treatment machine, a method using a snake pump, and A method using an extruder can be adopted.

(Alkenylation reaction) The catalyst used in the method of the present invention in which sodium metal is dispersed and supported on potassium carbonate is used in a proportion of alkylbenzene 1 existing in the reaction system.
The metal sodium is preferably 0.005 parts by weight or more and less than 5.0 parts by weight per 00 parts by weight. More preferably, it may be 0.01 to 2.0 parts by weight. When the amount of the metallic sodium used is less than 0.005 parts by weight, the reaction activity is low, and an excessively large reaction tank and / or reaction time are required to obtain the desired monoalkenylbenzene, which is preferable in industrial efficiency. Absent. On the other hand, when the amount of the sodium metal used is 5.0 parts by weight or more, a high polymer is produced as a by-product during the reaction,
Promotes poisoning of catalysts.

In the method of the present invention, the reaction between the alkylbenzene and the conjugated diene is preferably carried out in the range of 100 ° C to 200 ° C. If the reaction temperature is 100 ° C. or lower, the reaction time becomes long, and if it exceeds 200 ° C., side reaction products increase, which is not preferable. More preferable reaction temperature is 110-1.
It is 80 ° C. However, for example, o-xylene and 1,3
-The addition reaction of butadiene is an exothermic reaction, and the production of monoalkenylbenzene is accompanied by an exotherm of 25 kcal / mol. Therefore, as a heat removal method for keeping the reaction at a temperature of 100 to 200 ° C., a method of carrying out the reaction while boiling the reaction system and removing the reaction heat by the latent heat of vaporization is particularly preferable. Therefore, this reaction can be carried out by any of reduced pressure, normal pressure and increased pressure. Yes, but the reaction temperature is 144
It becomes ℃ -155 ℃.

In the method of the present invention, the total reaction time (average residence time) is in the range of 0.05 to 10 hours, preferably 0.5 to 8 hours.

The alkenylation reaction apparatus in the method of the present invention can be shown, for example, as shown in FIG. As shown in FIG. 1, a reaction vessel with a stirrer is used as one independent reaction zone, and a plurality of such reaction zones are used, or as shown in FIG. An example is a type of apparatus in which each reaction zone has an appropriate stirring device and is arranged so that the reaction liquid overflows and sequentially flows through a partition plate in a certain direction. Figure 1 shows, for example, o-xylene and 1,3
-A plurality of independent reaction tanks for addition reaction with butadiene are arranged in series, and the reaction liquid containing the alkenylbenzene produced in the reaction tanks is connected so as to flow in a certain direction between adjacent reaction tanks. It is an example of the prepared multi-stage reactor. For example, as shown in FIG. 1, raw materials such as o-xylene and a catalyst obtained by dispersing metallic sodium carbonate and potassium carbonate in an o-xylene or in an inert gas are continuously or intermittently supplied to a reaction tank 1. To do. On the other hand, for example,
1,3-Butadiene is a reaction tank 1, a reaction tank 2, a reaction tank 3,
The reaction tank 4 and the reaction tank 5 are divided and supplied.

The ratio of the division is not particularly limited, but is usually equally divided and supplied. The molar ratio of the total amount of the conjugated diene supplied to the amount of the alkylbenzene supplied to the reaction vessel 1 is appropriately 1: 4 to 1:80, preferably 1: 6 to 1: 1.
50.

In the method of the present invention, a part or the whole of the liquid containing alkylbenzene as a main component, which is evaporated by the boiling reaction and cooled and condensed, is circulated to the reaction tank upstream of the evaporated reaction tank as shown in FIG. .. Any reaction tank may be used as long as it is located on the upstream side, and any method may be used as a circulation method.

In the method of the present invention, the greater the circulating amount of the recovered liquid, the greater the effect of the present invention, and the greater the circulating position is on the upstream side of the flow of the reaction liquid. In the reactor, the concentration of the target monoalkenylbenzene increases as it passes through the reaction tank,
It becomes the maximum in the final reaction tank where the reaction solution is taken out.

After the reaction, in order to separate the used catalyst composed of sodium metal salt and potassium carbonate salt from the reaction solution, known means such as centrifugation, gravity settling separation, and filtration separation may be used. The separated and recovered catalyst can be recycled and used again in the reaction system. In addition, from the reaction liquid after separating the catalyst,
For example, by means such as distillation, unreacted alkylbenzene and the desired product, monoalkenylbenzene, can be separated and taken out. The unreacted alkylbenzene separated and recovered can be reused as a reaction raw material.

The desired product of the method of the present invention, such as 5- (o-
Trilyl) pentene is a useful compound that can be converted to naphthalene dicarboxylic acid useful as a polymer raw material by cyclizing and then oxidizing.
The purity of the monoalkenylbenzene when cyclizing the monoalkenylbenzene is important. For example, among 5- (o-tolyl) pentene, 5- (o-tolyl) pentene-
1,5- (o-tolyl) pentene-2 can be converted to the desired cyclization product, alkyltetraline, but
Not only is (o-tolyl) pentene-3,5- (o-tolyl) pentene-4 not convertible to alkyltetralin, but it also reacts with the target alkyltetralin to form a high boiling point product, reducing the yield of the target. Yes, and more effective 5
Separation from-(o-tolyl) pentene-1 and 5- (o-tolyl) pentene-2 is almost impossible even by rectification at a reflux ratio of 20 using a rectification column having 50 theoretical plates. On the other hand, in the reaction product obtained by the method of the present invention, such a by-product which is difficult to separate is extremely small, and therefore the reaction efficiency of the cyclized product is extremely high.

(Cyclization, dehydrogenation and isomerization reaction) The alkenylbenzene can be prepared by a method known per se, ie, sulfuric acid, solid phosphoric acid, an acid catalyst such as silica-alumina and 100 to 25%.
By contacting at a temperature of 0 ° C. for 10 seconds to 10 hours, cyclization can be performed to obtain an alkyltetralin.

Alkyl tetralins are prepared in a manner known per se, ie alumina-chromia, Pt / Al ₂ O ₃
Alkylnaphthalene can be dehydrogenated by contacting with a dehydrogenation catalyst such as the above at a temperature of 250 to 500 ° C. for 5 seconds to 5 hours.

Alkylnaphthalene is prepared by a method known per se, that is, a solid acid catalyst such as silica-alumina, ZSM-5, Y-type zeolite and H-type mordinite, and 100
The isomerization can be carried out by catalyzing at a temperature of ~ 450 ° C for 5 seconds to 10 hours. For example, 1,5-dimethylnaphthalene can be changed to 2,6-dimethylnaphthalene.

According to the present invention, dimethylnaphthalene, which is a useful compound as a raw material for polymer materials, can be produced from alkylbenzene as follows.

That is, for example, o-xylene and 1,3-
Reacting butadiene with a catalyst prepared by dispersing sodium metal with potassium carbonate to produce 5- (o-tolyl) pentene, and then cyclizing the 5- (o-tolyl) pentene by a method known per se. 1,5-dimethylnaphthalene can be produced, and then the 1,5-dimethylnaphthalene can be isomerized to produce 2,6-dimethylnaphthalene. Further, by oxidizing the 2,6-dimethylnaphthalene, naphthalene-2,6-dicarboxylic acid can be produced.

[0033]

INDUSTRIAL APPLICABILITY The reaction product obtained by the method of the present invention contains very few by-products which are difficult to separate.
The yield of cyclization reaction product is also very high.

According to the method of the present invention, a catalyst comprising sodium metal and potassium carbonate as a catalyst, preferably potassium metal salt dehydrated by high temperature calcination of sodium metal without causing oxygen and water to substantially exist. By reacting alkylbenzene and 1,3-butadiene in the presence of a fine powder and a catalyst which is dispersed at a specific ratio, an expensive and highly risky ignition metal natolim-potassium (Na-K: Nak) alloy is produced. Without using it directly, it is highly active and highly selective for alkenylation reaction,
Therefore, it becomes possible to suppress the production of by-products, which is difficult and complicated to separate from the target product, and to manufacture the target product with high purity in high yield. The catalyst used in the method of the present invention has an advantage that it can be easily separated at the time of catalyst preparation without the need for separation such as nuck, and the cost is low.

[0035]

EXAMPLES The present invention will be described in detail below with reference to examples. The selectivity of the target product of the alkenylation reaction in Examples and Comparative Examples was calculated by the following formula.

[0036]

[Equation 1]

[0037]

Example 1 A reactor having a capacity of 18 liters (effective volume of 10 liters) per reactor and a reactor with a heat-insulating jacket as shown in FIG. Reacted. Unreacted o- which was separated by distillation from the alkenylation reaction liquid obtained in this example and collected in the reaction tank 1.
The dehydrated o-xylene was mixed with xylene and an amount of dehydrated o-xylene consumed in the reaction, and the mixture was heated to 140 ° C. in a preheater and continuously supplied at a rate of 15.8 kg / hour. The reaction tanks 2 to 5 are heated with a heat medium from the jacket of the reaction tank so as to boil under normal pressure, and the evaporated vapor is condensed in the condenser of each reaction tank, and also passes through the fluid flow meter,
The whole amount was circulated in the reaction tank 1. The rotation speed of the stirrer in each reaction tank was set to 300 rpm, and the catalyst prepared by carrying in advance at a weight ratio of metallic sodium and potassium carbonate having an average particle diameter of 30 μm of 1:10 was supplied to the reaction tank 1 at a rate of 100 g per hour. ..

Five hours after starting the supply of o-xylene and the catalyst, dehydrated 1,3-butadiene was continuously introduced into each tank at a rate of 0.18 kg / h per tank (total of 5 tanks). 0.92 kg / h), and o-xylene and 1,3-
The reaction of butadiene proceeded. When the reaction status of each reaction tank became stable, the circulation amount of the total condensate to the reaction tank 1 was changed to 5.4 kg.
/ Hr was adjusted. The reaction liquid obtained from the reaction tank 5 is introduced into a sedimentation separator to separate the catalyst used in the reaction, and then the unreacted o-xylene is circulated to the reaction tank 1 by distillation in a vacuum distillation column to continue reuse. It was Further, the distillation still residue is subjected to precision distillation and 5-
It was possible to continuously obtain the target product having a purity of 99.7%, which is a combination of (o-tolyl) pentene-1 and 5- (o-tolyl) pentene-2, at a rate of 2.3 kg / h. In this state,
Table 1 shows the results of analysis of the compounds in the reaction solution obtained from the reaction tank 5 by distillation and gas chromatography, which were operated continuously for 3 days.

[0039]

Comparative Example 1 The compound in the reaction solution obtained from the reaction vessel 5 was distilled in the same manner as in Example 1 except that the evaporation fraction of each reaction vessel was returned to the vaporized reaction vessel. Table 1 shows the results of analysis by the gas chromatography method and the gas chromatograph method.

[0040]

[Table 1]

[0041]

Example 2 This example is an example of synthesizing 2,6-dimethylnaphthalene by cyclization reaction, dehydrogenation reaction and isomerization reaction of 5- (o-tolyl) -pentene.

(A) Synthesis of 1,5-dimethyltetralin by cyclization reaction of 5- (o-tolyl) -pentene 5- (o-tolyl) -pentene having a purity of 99.0% obtained in Example 1 The cyclization reaction was carried out using a 10% toluene solution of. Using solid phosphoric acid as a catalyst, the reaction temperature is 15
As a result of carrying out in a nitrogen atmosphere at 0 to 200 ° C., the conversion rate of the raw material is 100%. The formation selectivity of 1,5-dimethyltetralin, which is a cyclized product, was 95% or more.

(B) Synthesis of 1,5-dimethylnaphthalene by dehydrogenation reaction of 1,5-dimethyltetralin Dehydration using a 10% toluene solution of 1,5-dimethyltetralin obtained by the method of (A) above. An elementary reaction was performed.
As a result of dehydrogenation at 400 ° C. in a hydrogen atmosphere using a 0.3% Pt / Al ₂ O ₃ catalyst as a dehydrogenation catalyst, 1,5-
1,5-Dimethylnaphthalene was obtained with a conversion of dimethyltetralin of 99% and a selectivity of 1,5-dimethylnaphthalene of 97%.

(C) Synthesis of 2,6-dimethylnaphthalene by isomerizing 1,5-dimethylnaphthalene 1,5-dimethylnaphthalene obtained by dehydrogenation by the method (B) is isomerized to give 2,5-dimethylnaphthalene. An experiment was conducted to synthesize 6-dimethylnaphthalene.

As a result of carrying out the isomerization reaction in a nitrogen atmosphere in the presence of an alumina dispersed catalyst containing 30% of H-type mordenite at a temperature of 350 to 400 ° C. using a 10% toluene solution of 1,5-dimethylnaphthalene. , 1,5-dimethylnaphthalene 10%, 2,6-dimethylnaphthalene 43
%, 1,6-dimethylnaphthalene 44%, and another naphthalene compound 3%. When this was crystallized and separated, 50% of 98% pure 2,6-dimethylnaphthalene was recovered.

[Brief description of drawings]

FIG. 1 shows an example of a reaction apparatus used in the present invention.

FIG. 2 shows an example of a reaction apparatus used in the present invention. You

[Explanation of symbols]

 A o-xylene B Dispersion treatment catalyst C 1,3-Butadiene D Reaction liquid E Vent F Cooling water G Condenser H Stirrer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C07C 13/48 8619-4H 15/24 8619-4H // C07B 61/00 300 (72) Inventor Koji Sumitani 2345 Nishigaki Town, Matsuyama City, Ehime Prefecture Matsuyama Office of Teijin Limited (South Area)

Claims (9)

[Claims] 1. In producing a monoalkenylbenzene by reacting an alkylbenzene with a conjugated diene,
(A) A catalyst composed of metallic sodium and potassium carbonate is used, (B) a plurality of independent reaction zones are arranged in series, and the reaction zones are connected so that the reaction solution can flow in a certain direction. (C) starting material alkylbenzene and catalyst are fed to at least the first reaction zone, (D) starting material conjugated diene is fed to at least two or more reaction zones, and (E) at least A process for producing monoalkenylbenzene, characterized in that one reaction zone is kept in a boiling state, and (F) the reaction liquid is taken out from the last reaction zone. 2. The method according to claim 1, wherein the alkylbenzene is any one of toluene, ethylbenzene, o-xylene, p-xylene and m-xylene. 3. The conjugated diene is 1,3-butadiene and / or
Alternatively, the production method according to claim 1, which is isoprene. 4. The average particle size of potassium carbonate is 150 μm.
The manufacturing method according to claim 1, wherein: 5. The production method according to claim 1, wherein a catalyst in which metallic sodium is dispersed and carried on a potassium carbonate salt is used. 6. The production method according to claim 5, wherein the amount of metallic sodium dispersed and supported on the potassium carbonate salt is 1.0 part by weight or more and less than 100.0 parts by weight per 100 parts by weight of the potassium carbonate salt. 7. The method according to claim 1, wherein the amount of metallic sodium used is 0.005 parts by weight or more and less than 5.0 parts by weight per 100 parts by weight of alkylbenzene present in the reaction system. 8. A method for producing alkyltetralin, which comprises cyclizing the alkenylbenzene obtained by the method according to claim 1. 9. A method for producing an alkylnaphthalene, which comprises dehydrogenating alkyltetralin obtained by the method according to claim 8.