JP3327712B2 - Method for producing alkenyl compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a raw material for producing naphthalenedicarboxylic acid useful as a polymer raw material such as polyethylene naphthalate (PEN), and produces an alkenyl compound having high industrial value. About the method.

[0002]

2. Description of the Related Art Conventionally, a method for producing an alkenyl compound by reacting an alkylbenzene with 1,3-butadiene in the presence of an alkali metal is a method using metal potassium as a catalyst. (Japanese Patent Publication No. 50-17773), a method in which metal potassium and metal sodium are used in combination (Japanese Patent Publication No. 56-57070).
Nos. 57-26489 and 50-17773) are known.

[0003] However, these methods have the following problems. (1) Production cost is high because expensive metal potassium is used. (2) Potassium metal is highly reactive with water, air, etc., and ignites only upon contact with them, acting as an ignition source for combustible raw materials and products. However, it is very dangerous because metal potassium having such an effect is directly used.

In addition, a method of using metallic sodium and an inorganic potassium salt without using metallic potassium having such a problem (JP-A-47-31935, WO91-1).
No. 6284, JP-A-4-226927) are also known.

However, in this method, (3) it is necessary to use a special stirring device such as an emulsifying device, and it is also necessary to use an inorganic potassium salt having a high degree of purification. Can not.

Further, Japanese Patent Application Laid-Open No. 6-107569 discloses a method which does not use a special stirring device as described above. Further, a meniscus-shaped stirring blade using metal sodium and an inorganic potassium salt as a catalyst is disclosed. When using a stirrer equipped with, a little reaction occurs, but by using glass beads or α-alumina balls for shaving the surface of the powdery catalyst, the reaction yield may be significantly improved. It has been disclosed.

However, in this method, (4) glass beads having a large average particle size (about 2.0 to 3.0 mm) or α-
The use of alumina balls causes rotation impairment of the stirring blade and wear of the device.

[0008] In addition, a method is also known in which the reaction is carried out using only a metal Na catalyst (Dimitror.ch, et.a.
1, Dokl. Borg Akad. Nauk. , 3
3, 353 (1980)).

However, this method has a problem that (5) it is necessary to use a large amount of metallic Na as much as 7.9 wy% with respect to o-xylene, and the yield is extremely low at 31.6%.

The present invention solves all of the problems (1) to (5) in the conventional methods as described above and provides a method for producing an alkenyl compound from alkylbenzene and 1,3-butadiene in high yield. The purpose is to propose.

[0011]

Means for Solving the Problems The present inventor has conducted various studies to achieve the above object, and as a result, as a catalyst, metal N
In a system using a, a predetermined reaction pressure was applied to react alkyl benzene with 1,3-butadiene. As a result, it was possible to produce an alkenyl compound in high yield without using a large amount of metal Na. I got the knowledge that I can do it.

The present invention is based on the above findings. In producing an alkenyl compound by reacting an alkylbenzene with 1,3-butadiene, sodium metal is present in the presence of 1 kPa [gage] to 30 MPa [gag].
A method for producing an alkenyl compound, characterized by applying a reaction pressure of e).

The alkylbenzene in the method of the present invention has one or two methyl or ethyl groups in the benzene nucleus, and specifically includes toluene, ethylbenzene, o-xylene, m-xylene, p-xylene. Xylene is mentioned. Each of these alkylbenzenes is preferably used alone, and when two or more are used in combination, it becomes difficult to isolate each of the target substances from the alkenyl compounds as reaction products with high purity.

The purity of the alkylbenzene alone is preferably as high as possible in order to facilitate the isolation of the desired product. Specifically, the purity is preferably 95% or more, more preferably 98% or more. However, hydrocarbons having no alkyl group, such as benzene and cyclohexane, may be slightly mixed.

Since the water contained in the alkylbenzene causes deterioration of the catalyst, specifically, deactivation of sodium metal, the lower the water content of the alkylbenzene, the better. The Karl Fischer method, which is a usual method for measuring water content, is preferred. The sensitivity is preferably equal to or less than the measurement sensitivity of the method, specifically, several ppm or less. Therefore, it is preferable to use dehydrated alkylbenzene.

As a method for dehydrating alkylbenzene, for example, a method of adsorbing and separating water using a suitable drying agent (activated alumina, silica gel, molecular sieve, activated carbon, etc.) or a method of cryogenic separation, There is a method of dehydrating by contacting with sodium or metal potassium. Preferably, it is a method of bringing into contact with metallic sodium and metallic potassium to perform dehydration.

As the 1,3-butadiene to be reacted with the above-mentioned alkylbenzene, any one produced by any method can be used. In addition, the purity of 1,3-butadiene does not need to be as high as that of the above-mentioned alkylbenzene, and the reaction proceeds satisfactorily regardless of the purity, and the isolation of the target product can be achieved. There is no hindrance at all. For example, crude butadiene obtained by dehydrogenation of butane or butene can be used as it is, or 1,3-butadiene obtained by purifying the crude butadiene by a method such as extraction.

However, the water content of 1,3-butadiene is
For the same reason as in the case of the above-mentioned alkylbenzene, the lower the better, the better, specifically, a few ppm or less. Therefore, it is preferable to use dehydrated 1,3-butadiene.

The method for dehydrating 1,3-butadiene includes:
For example, similar to the above alkylbenzene dehydration method,
There is a method of adsorbing and separating water with a suitable drying agent (activated alumina, silica gel, molecular sieve, activated carbon, etc.) or a method of cryogenic separation.

Metal sodium, which is a catalyst for reacting the above-mentioned alkylbenzene with 1,3-butadiene,
Higher purity is better, but it may contain trace amounts of calcium, magnesium and potassium. The purity is preferably 90% or more, more preferably 99.0% or more.

The amount of metallic sodium used is 0.001-2 wt%, preferably 0.005-1 wt%, based on the reaction solution (total amount of alkylbenzene and 1,3-butadiene as reaction raw materials). Preferably 0.05 to
1 wt%. If the amount of metallic sodium is less than 0.001 wt%, the effect of the catalyst in the method of the present invention will be insufficient, and if it is more than 2 wt%, the effect of the catalyst will be saturated and uneconomical.

In the method of the present invention carried out in the presence of the above-mentioned metallic sodium, the reaction pressure is 1 kPa [gage].
~ 30 MPa [gage], preferably 1 kPa [ga
ge] to 10 MPa [gage], more preferably 10
The pressure is set to kPa [gage] to 1 MPa [gage]. 1
If the pressure is less than kPa [gage], almost no target alkenyl compound can be obtained in the above-mentioned amount of sodium metal used, and if the pressure is higher than 30 MPa [gage], a side reaction product will be generated.

The above-mentioned pressure may be secured by the vapor pressure of the starting compound by heating the alkylbenzene to a temperature higher than the boiling point, or supplying 1,3-butadiene in an amount required for the reaction to the reaction system. , Or an inert gas.

In the process of the present invention carried out in the presence of the above-mentioned sodium metal and the above-mentioned reaction pressure, the reaction molar ratio of alkylbenzene to 1,3-butadiene is appropriately selected under ordinary conditions. For example, alkylbenzene: 1,3-butadiene {1: 0.001-0.5, preferably 1: 0.01-0.4, more preferably 1:
0.05 to 0.3.

In the method of the present invention, the reaction between alkylbenzene and 1,3-butadiene is preferably carried out in the absence of water and oxygen. This is because moisture causes deactivation of sodium metal (changes to sodium hydroxide) as described above, and oxygen inactivates sodium metal.

Therefore, as described above, it is desirable to use dehydrated raw materials, ie, alkylbenzene and 1,3-butadiene, which are introduced into the reaction system from outside the system. The space in the reaction system is also filled with a dry inert gas such as dry nitrogen, dry argon or the like in order to substantially prevent oxygen or moisture from being present, or the reaction is carried out under a pressure reaction condition higher than the boiling point of alkylbenzene. In the case of performing the process below, it is desirable to fill the space with vapor such as alkylbenzene.

Further, in the method of the present invention, the reaction is
It is preferable to carry out in the range of about 50 to 200 ° C. 50
When the temperature is lower than 0 ° C, a side reaction product is generated or the reaction time of the main reaction becomes longer. Preferred reaction temperatures are between 80 and 180 ° C.

It is generally preferred that the reaction time be within the range of 0.05 to 10 hours. The reaction time is the amount of the catalyst (g-metal sodium), the reaction temperature (° C.), the molar ratio of alkylbenzene to 1,3-butadiene (g-alkylbenzene / g-1,3-butadiene), or the reaction method (described later). (Refers to a batch reaction or a continuous reaction), and an appropriate time is selected depending on the purity of the target product, the mode of use of the catalyst (for example, the presence or absence of circulation use), and the like. In general, if these factors decrease,
Although the reaction time becomes longer, the preferred reaction time is 0.1 to
8 hours, more preferably 0.3 to 5 hours.

In the reaction, a raw material (alkylbenzene, 1,3-butadiene) and a catalyst (metallic sodium) are simultaneously charged and reacted from the beginning, and a batch reaction is carried out in which alkylbenzene and a catalyst are charged first, and then 1,3-butadiene is reacted. Semi-batch reaction to introduce quantitatively with the passage of time, continuous reaction to continuously introduce alkylbenzene, 1,3-butadiene and a catalyst into a reactor, filling a reaction tower with a catalyst, and transferring alkylbenzene and 1,3-butadiene to the top of the tower and Any of the reactive distillation methods (details will be described later) of the embodiment shown in FIG. 1 in which the target product is introduced from the bottom of the column and the target product flows down to the bottom of the column may be employed, and they may be appropriately combined. Although 1,3-butadiene may be a polymer or 1,3-butadiene is added to an alkylbenzene or two or more 1,3-butadiene. From the viewpoint of suppressing the production of by-products such as compound, semibatch reaction, continuous reaction, or the reaction distillation method is preferable.

In the case of the above continuous reaction, two types are employed. That is, in the method of the present invention, (1)
A method in which alkylbenzene is continuously passed through a fixed bed of a catalyst and a continuous reaction is carried out while introducing 1,3-butadiene into the alkylbenzene; and (2) the catalyst is used in a reaction system between alkylbenzene and 1,3-butadiene. There is a method in which the reaction is carried out while stirring and dispersing. In the continuous reaction, any of a tubular reactor, a column reactor, and a tank reactor may be used. A preferred method for a continuous reaction is
This is a cross-flow type continuous reaction system in which a plurality of reaction zones are provided, and 1,3-butadiene is quantitatively introduced into each reaction zone.

The reaction operation in the continuous reaction is not particularly limited as long as alkylbenzene and 1,3-butadiene can be sufficiently contact-mixed in the presence of a catalyst.

However, it is necessary to add 1,3-
In the method of introducing butadiene, a resinous or gum-like substance presumed to be a polymer of 1,3-butadiene tends to adhere to the vicinity of the inlet of 1,3-butadiene, causing a clogging phenomenon. Into a reaction system in which is present a mixed phase of 1,3-butadiene and alkylbenzene, for example, a liquid phase mixture of liquid butadiene and liquid alkylbenzene, a gas-liquid mixture of gaseous 1,3-butadiene and liquid alkylbenzene, etc. And a method of introducing 1,3-butadiene and alkylbenzene is preferable.

Alternatively, clogging can be prevented by supplying 1,3-butadiene to the reaction space to cause an absorption reaction on the surface of the reaction solution in which the catalyst is present.

When introducing 1,3-butadiene,
The stirring effect can be added at the same time as the blowing, together with the carrier gas. As the carrier gas at this time, an inert gas from which oxygen and moisture have been removed, for example, nitrogen, argon, and hydrogen is appropriate.

Further, the reaction can be preferably carried out by adding appropriate stirring. However, it is also possible to introduce 1,3-butadiene into the reaction system in a gaseous phase and to give the gas a stirring effect. It is desirable that the stirring has a strength necessary for uniformly dispersing the catalyst in the reaction system and for uniformly mixing the raw material and the reaction product.

When the reaction is carried out in a liquid phase dispersion reaction system, after the reaction,
In order to separate the used catalyst from the reaction product system, for example, known means such as centrifugal sedimentation, gravity sedimentation, and separation of a solid phase from a liquid-solid phase at a low temperature (eg, filtration, centrifugation, etc.) can be used. Good.

The separated catalyst can be recycled to the reaction system. When the catalyst deactivates and loses its catalytic function,
It becomes inactive sodium hydroxide. Therefore, the inactivated metal sodium is added and reused.

In the reactive distillation method, 1,3-butadiene 2 is added to alkylbenzene which is one of the by-products.
Since it is difficult to produce an adduct or more, the reaction time can be arbitrarily long without being limited to the above reaction time. The reaction time in the reactive distillation method is mainly
It is determined by the feed rate of 1,3-butadiene and the tower length of the catalyst packed region.

Next, the reactive distillation method will be described in detail with reference to FIG. In the figure, reference numeral 10 denotes a reactive distillation column, and a portion 11 is filled with the above-mentioned catalyst of the present invention. The raw material alkylbenzene is supplied from the line 1 and flows out of the tower to the line 4, is condensed in the cooler 13, passes through the gas-liquid separator 14 via the line 5, and is unreacted to the line 6. Along with unreacted alkylbenzene which is separated from 3-butadiene and taken out to the line 7, it is charged into the reactive distillation column 10 from the top side.

On the other hand, 1,3-butadiene is charged in a gaseous or liquid state from the line 2 to the lowermost part of the portion 11 filled with the catalyst, and comes into contact with the alkylbenzene while moving to the top, and the alkenyl Produce compound.

Since the produced alkenyl compound is a substance having a higher boiling point than alkylbenzene and 1,3-butadiene, most of the alkenyl compound is liquid at a temperature at which alkylbenzene can coexist in gas and liquid, and flows down to the bottom of the column. A part of the bottom product is taken out to a line 8 and heated in a reboiler 12 to a temperature lower than a temperature at which the total amount of the target alkenyl compound is vaporized and higher than a temperature at which alkylbenzene is completely vaporized. It is returned to the distillation column 10. The remainder is collected as a product alkenyl compound from line 3 after cooling in cooler 15.

The reaction pressure in the reaction system is within the range of the present invention, ie, 1 kPa [gage] to 30 MPa [gage] by the pressure holding valve 16 provided in the line 6.
It is adjusted to.

Thus, in this reaction mode, unlike the batch reaction mode, the product does not come into further contact with 1,3-butadiene, and thus the fluid taken from line 3 is substantially unreacted. It is composed solely of the alkenyl compound which is the target product without the alkylbenzene or disubstituted by-product.

According to the method of the present invention, 5-phenyl-pentene is synthesized when toluene is used as the alkylbenzene, and 5-phenyl-pentene is synthesized when o-xylene is used.
When (o-tolyl) -pentene uses p-xylene, 5- (p-tolyl) -pentene is used, and when m-xylene is used, 5- (m-tolyl) -pentene is ethylbenzene. Is used, 5- (phenyl) -hexene is respectively synthesized.

[0045]

【Example】

Example 1 0.45 parts by weight of metallic sodium and 200 parts by weight of o-xylene were put into a 500 ml (hereinafter, referred to as "mL") pressure-resistant autoclave, and a stirring device equipped with a half-moon plate stirring blade was used. At a rotation speed of 500 rpm, 140
After stirring at 1.0 ° C. for 1.0 hour, the temperature was raised to 150 ° C., and a pressure of 100 kPa [gage] was
1,3-Butadiene was introduced into the reaction solution at a rate of 7.0 mL / min over 3 hours.

After the completion of the reaction, the mixture was immediately cooled to 100 ° C.
The metallic sodium and the reaction solution were separated. The reaction solution is
After washing with distilled water, it was separated, excess o-xylene was distilled off, and 5- (o-tolyl) -pentene was obtained by distillation under reduced pressure. The yield and purity of the 5- (o-tolyl) -pentene were measured, and the results are shown in Table 1.

Examples 2 to 15 and Comparative Examples 1 and 2 The same operation as in Example 1 was carried out except that the composition of the catalyst and the pressure and temperature of the reaction were as shown in Table 1, to obtain 5- (o-
Tolyl) -pentene was obtained. In Comparative Examples 1 and 2, the rotation speed was increased to 1200 rpm. The yield and purity of 5- (o-tolyl) -pentene were measured.
Are shown together.

As is evident from Table 1, according to the method of the present invention, the desired product 5- (o-tolyl)-is obtained in high yield.
It turns out that pentene can be obtained.

[0049]

[Table 1]

The wt% of metallic Na in Table 1 is the wt% based on the alkylbenzene (the same applies to the following tables).

Examples 16 to 25, Comparative Examples 3 to 4 The same operation as in Example 1 was carried out except that p-xylene was used instead of o-xylene and the composition of the catalyst was as shown in Table 2. -(P-Tolyl) -pentene was obtained. This 5-
The yield and purity of (p-tolyl) -pentene were measured, and the results are shown in Table 2.

As is clear from Table 2, according to the method of the present invention, the desired compound 5- (p-tolyl)-is obtained in high yield.
It turned out that pentene could be obtained.

[0053]

[Table 2]

Examples 26 and 27 The same operation as in Example 1 was carried out except that m-xylene (Example 18) or ethylbenzene (Example 19) was used instead of o-xylene, to obtain 5- (p-tolyl). ) -Pentene was obtained. The results are shown in Table 3.

[0055]

[Table 3]

[0056]

According to the method of the present invention, the following effects can be obtained. (1) An alkenyl compound can be produced very efficiently, and the yield can be greatly improved. (2) By setting the reaction pressure to a predetermined value, even when the amount of metal sodium used as the catalyst is small, the alkenylation reaction occurs with high activity and high selectivity, and therefore, it is difficult to separate from the target product. It is possible to suppress the generation of various by-products and to obtain a high-purity target product in a high yield. (3) By-products that are difficult to separate in the obtained reaction product can be extremely reduced, and thus the yield of the target product can be extremely increased.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of a device configuration when a method of the present invention is performed.

[Explanation of symbols]

1 Introduction line for alkylbenzene as raw material 2 Introduction line for 1,3-butadiene as raw material 3 Collection line for alkenyl compound as target product 4,5,7 Removal / return line for unreacted alkylbenzene 6 Uncondensed extraction line 8, 9 Unreacted 1,3-butadiene take-out / return line 10 Reaction tower 11 Distillation structure filling section 12 Reboiler 13, 15 Cooler 14 Gas-liquid separator 16 Holding pressure valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-27042 (JP, A) JP-A-48-431 (JP, A) JP-A-5-170674 (JP, A) JP-A-6-274 234669 (JP, A) JP-A-6-9443 (JP, A) JP-A-5-310613 (JP, A) JP-A-7-196544 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 15/44 C07C 2/72

Claims (1)

(57) [Claims] In producing an alkenyl compound by reacting an alkylbenzene with 1,3-butadiene,
In the presence of metallic sodium, 1 kPa [gage] to 3
A method for producing an alkenyl compound, comprising applying a reaction pressure of 0 MPa [gage].