JP2001048852A - Production of diels-alder adduct from conjugated diolefin and acrylonitrile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production process for a Diels-Alder adduct that can inhibit the polymer from sticking to the inner wall of the reactor. SOLUTION: In the case that a reactor of the tank type is used, the reactor having a partial vapor-phase space is increased the inner pressure by introducing an inert gas, then a mixture of conjugated diolefin and acrylonitrile is fed in liquid-phase to produce the Diels-Alder adduct thereof, the inner wall of the reactor, the outer face and the inner face of the mixture-delivering pipes are made their roughness <=5 μm and the pipes for feeding the mixture is immersed in the reaction mixture thereby feeding the feedstock into the liquid phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile by reacting the conjugated diolefin with acrylonitrile.

[0002]

2. Description of the Related Art A method for producing a Diels-Alder adduct of a conjugated diolefin with acrylonitrile by a Diels-Alder reaction between conjugated diolefin and acrylonitrile is known. Since this reaction proceeds thermally, It is desirable for the reaction to proceed, but in this case, it is known that the amount of polymer produced in the reaction solution also increases.

[0003] The above-mentioned polymer is supplied near the raw material introduction portion of the reactor,
A polymer insoluble in the reaction solution (hereinafter, referred to as an insoluble polymer) adheres or accumulates in the vicinity of the reaction solution outlet or on the inner wall, causing problems in operation. In order to avoid this, conventionally, a method of adding various polymerization inhibitors has been proposed as a method for suppressing by-products of the polymer. For example, as a measure for preventing the polymerization of diolefins or olefins in the Diels-Alder reaction, a method involving the presence of an N-nitrosamine compound (Japanese Patent Publication No. 54-9198) and a method involving the presence of an alkylphenol compound (JP-A-61-165)
No. 338), a method in which a p-phenylenediamine compound is present (Japanese Patent Publication No. 57-7131), and a method in which a hydroxylamine compound is present (Japanese Patent Application Laid-Open No. 62-167733).
Etc. are known.

Further, in a method of producing a conjugated diolefin using dicyclopentadiene and producing a cyanonorbornene by a Diels-Alder reaction with acrylonitrile, for example, a reaction is carried out in the coexistence of an N-nitrosamine compound (Japanese Patent Laid-Open No. No. 7-188147) or a method in which cyanonorbornene is previously added to a reaction raw material (Japanese Patent Publication No. 59-188147).
-51533).

On the other hand, in the reaction between dicyclopentadiene and acrylonitrile, as a method for reducing the amount of by-products of the polymer and improving the yield of cyanonorbornene, when reacting under a pressure higher than the self-generated pressure of the raw material, A method has been proposed in which a raw material is supplied into a reaction solution from a lower portion of a reactor and the reaction solution is taken out from an upper portion to keep the raw material in a liquid phase (JP-A-51-34139).

However, according to the study of the present inventors, when a conjugated diolefin is reacted with acrylonitrile, an extremely insoluble polymer is easily formed in a reactor or a pipe depending on the reaction method and mode. Alternatively, it was found that the reaction was accompanied by danger.

That is, the inventors of the present invention have made various aspects such as using a so-called tubular type or tank type reactor in which a conjugated diolefin and acrylonitrile are reacted by heating in a spiral pipe. The reaction was carried out.
As a result, in the case of employing a so-called tubular reaction method in which conjugated diolefin and acrylonitrile are reacted in a pipe, an insoluble polymer adheres to the inner wall surface, and further causes a clogging phenomenon in the pipe. It turns out that it is hardly feasible for continuous production operations. In addition, when the reaction is performed in a full state using a tank-type reactor, the phenomenon that the insoluble polymer adheres to the reactor wall is avoided, but the pressure inside the reactor fluctuates rapidly, which is extremely dangerous. There is, furthermore, in this case, an insoluble polymer adheres to a raw material supply pipe for supplying a raw material into a reaction solution or to an outlet from the pipe, which eventually causes a clogging phenomenon,
I got the knowledge. Therefore, the method described in JP-A-51-34139 is effective as a method for improving the yield of cyanonorbornene by reducing the amount of by-products of the polymer, but allows the reaction to be performed safely. It turned out to be difficult.

As described above, although there have hitherto been found ones aimed at suppressing the formation of insoluble polymer in the reaction solution during the reaction, the formation of insoluble polymer can be significantly suppressed. Nothing was described about the structure or mode of the reactor and the method for safely carrying out the reaction.

Therefore, the present inventors first used a tank-type reactor in the reaction between conjugated diolefin and acrylonitrile, and used an inert gas for the reaction by allowing a gas phase portion to exist in the reactor. And pressurize to release a premixed conjugated diolefin or a mixture of acrylonitrile and a compound that generates conjugated diolefins in the reactor from the top of the reactor into the gas phase, drop it into the liquid phase, and react to form a reaction. A method for producing an adduct of a conjugated diolefin and acrylonitrile while taking out the product from the lower part of the reactor, significantly suppressing the formation of insoluble polymer even under a high-temperature reaction at 180 to 200 ° C, and performing the reaction safely. (Japanese Unexamined Patent Publication No.
No. 263574).

[0010] Further, a conjugated diolefin and acrylonitrile are converted into an inert gas for the reaction by using a tank-type reactor in which the surface roughness of the inner wall of the reactor is 5 μm or less and having a gas phase portion in the reactor. The pressure is increased using a conjugated diolefin or a mixture of acrylonitrile and a compound that generates a conjugated diolefin in the reactor is discharged from the upper part of the reactor into the gas phase, dropped to the liquid phase and reacted, and the reaction product is formed. By taking out from the lower part of the reactor, higher temperature of 200-220 ℃
Discloses a method for producing an adduct of a conjugated diolefin and acrylonitrile while remarkably suppressing the formation of an insoluble polymer even under the reaction of (1) and performing the reaction safely (Japanese Patent Laid-Open No.
11-100362).

[0011]

However, based on the above findings, the present inventors have further studied for practical use. However, when the conjugated diolefin and acrylonitrile are continuously reacted for a long time, It has been clarified that the polymer may still adhere to the top plate portion (the inner wall of the ceiling portion) in the reactor particularly by the reaction method and the mode.

That is, the present inventors used a tank-type reactor in which the surface roughness of the entire inner wall of the reactor was 5 μm or less,
An experiment was conducted in which a conjugated diolefin or a mixture of acrylonitrile and a compound that generates conjugated diolefins in the reactor was discharged from the upper part of the reactor into the gas phase, dropped into the liquid phase, supplied with raw materials, and reacted. When using a larger test equipment instead of a laboratory scale and conducting the test continuously for a longer period of time, the polymer does not adhere to the raw material supply piping and the inner wall of the liquid phase inside the reactor, but the reactor air It was found that the polymer adhered to the phase top plate.

Usually, instruments such as a pressure gauge, valves and the like are provided on the top plate of the reactor in an actual production facility. There is a concern that there will be problems in conducting the production operation.

Therefore, the above-mentioned conventional method for producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile is a continuous production reaction within a limited range of time, or a continuous reaction is carried out every time. Stopping and removing the polymer in the gas phase top plate in the reactor is a meaningful method that can be carried out industrially, but without stopping the reaction at all, it is possible to maintain a stable continuous It has been found that this method still has problems to be solved in enabling manufacturing operations.

Conventionally, in the reaction between a conjugated diolefin and acrylonitrile, the production of a polymer in the liquid phase in the reactor is suppressed, and at the same time, when the reaction is carried out for a long period of time, the gas phase in the reactor is There is no description about the structure and mode of the reactor capable of suppressing the formation of a polymer on the top plate.

An object of the present invention is to suppress the formation of a polymer in the liquid phase of a reactor when a Diels-Alder adduct of a conjugated diolefin and acrylonitrile is produced by a Diels-Alder reaction between a conjugated diolefin and acrylonitrile. At the same time, the production of polymer on the gas phase top plate in the reactor is remarkably suppressed, and continuous production operation can be easily performed without any trouble in the long term. Is to do.

[0017]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, in order to prevent the polymer from adhering to the top plate in the gas phase part in the reactor, the raw material is in the gas phase part. The present invention has been found that the object can be achieved by supplying directly to the liquid phase portion in the reactor by using a supply pipe instead of the supply pipe, and further using the supply pipe without fine irregularities on the surface. Was completed.

That is, the present invention provides (1) a tank-type reactor, in which a gas phase is present in the reactor and the pressure is increased using an inert gas for the reaction, and the conjugated diolefin or the reactor is used. A mixed solution of a compound generating conjugated diolefin and acrylonitrile in the reactor is supplied and reacted to produce a Diels-Alder adduct of conjugated diolefin and acrylonitrile, the inner wall of the reactor and the reactor. The outer surface and the liquid supply port of the raw material supply pipe for supplying the above-mentioned mixed liquid in the inside thereof have a surface roughness of 5 μm or less, and the mixed liquid is supplied into a liquid phase in a reactor. A method for producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile, and (2) a reaction temperature of 180 to 220 ° C.
(1) The method according to (1), wherein the volume of the gas phase is 10 to 50% of the total internal volume of the reactor.
And (4) the reaction pressure is 6 to
The production method according to the above (1), which is 80 kg / cm ² · G,
Further, (5) the production method according to the above (1), wherein the gas inert to the reaction is nitrogen, argon, helium, methane, ethane, propane, n-butane or isobutane;
(6) The method according to the above (1), wherein the compound generating the conjugated diolefin is dicyclopentadiene, and the pressure during the reaction is 6 to 30 kg / cm ² · G. pressure is the production method of the above (6), wherein a 6~10kg / cm ² · G, also (8) conjugated diolefin is butadiene and the pressure during the reaction is 50~80kg / cm ² · G Is above
(9) The method according to the above (8), wherein the gas inert to the reaction is nitrogen, argon, helium, methane or ethane, and (9) The conjugated diolefin is isoprene, and the pressure during the reaction is 30 to
The production method according to the above (1), wherein the production method is 60 kg / cm ² · G,
Further, (11) the gas inert to the reaction is nitrogen, argon, helium, methane, ethane or propane is the production method according to the above (10), and (12) conjugated diolefin or a reaction mixed in advance The method according to the above (1), wherein an N-nitrosamine compound or a p-phenylenediamine compound is allowed to coexist in a mixture of a compound that generates a conjugated diolefin and acrylonitrile in a vessel. The above (N) -nitrosamine compound is N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosomethylethylamine, N-nitrosodiphenylamine, N-nitrosobenzylaniline, or 4-nitroso-N, N-dimethylaniline. 12) The manufacturing method according to the above,
(14) The method according to the above (12), wherein the p-phenylenediamine compound is N-phenyl-N′-isopropyl-p-phenylenediamine.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a tank-type reactor used for reacting a conjugated diolefin with acrylonitrile is a container having a shape capable of storing a liquid therein and a hermetically sealed container. Although it can be used in a wide range as long as it is not particularly limited, usually, a cylindrical shape, a spherical shape, an inverted conical shape, or a combination thereof is often used.

Further, the surface roughness representing minute irregularities on the inner wall of the reactor (the surface roughness referred to in the present invention is the definition of surface roughness defined in Japanese Industrial Standard JIS-B-0601 (1955). The same) is preferably 5 μm or less, more preferably 1 μm or less.

In the present invention, the reaction between the conjugated diolefin and acrylonitrile is carried out in a liquid phase, and the pressure is increased by using an inert gas for the reaction by allowing a gas phase portion to exist in the reactor. In this case, if the volume of the gas phase is made too small, the reaction will be accompanied by a sudden change in the pressure in the reactor during the reaction, which is extremely dangerous.If the gas phase is made too large, the volume efficiency will be reduced. Due to disadvantages, the volume of the gas phase is 10 to 10% of the total internal volume of the reactor.
The reaction is preferably performed in a range of 50%, and more preferably in a range of 20 to 40%.

The pressure during the reaction in the present invention depends on the type of the conjugated diolefin used or the compound that generates the conjugated diolefin in the reactor, but it is 6 to 80 kg / cm ² ···.
It is preferable to carry out in the range of G. The inert gas used for the reaction when the pressure is increased depends on the type of the conjugated diolefin used or the compound generating the conjugated diolefin in the reactor. As long as it has no extreme absorption, it is at least one selected from nitrogen, argon, helium, methane, ethane, propane, n-butane and isobutane. Normally, nitrogen can be preferably used because of easy availability, and sufficient results can be obtained.

In the present invention, when the compound generating a conjugated diolefin is dicyclopentadiene, the reaction is preferably carried out under a pressure of 6 to 30 kg / cm ² · G, more preferably 6 to 30 kg / cm ² · G. More preferably, the reaction is performed within a range of 10 kg / cm ² · G. When the conjugated diolefin is butadiene, the pressure during the reaction is 50 to 80.
The reaction is preferably carried out in the range of kg / cm ² · G,
The gas inert to the reaction used when increasing the pressure is preferably at least one selected from nitrogen, argon, helium, methane and ethane. Further, when the conjugated diolefin is isoprene, the pressure during the reaction is 30
The reaction is preferably carried out at a pressure in the range of ~ 60 kg / cm ² · G, and the inert gas used for the reaction when the pressure is increased is at least one selected from nitrogen, argon, helium, methane, ethane and propane. Is preferred.

In the present invention, a raw material supply pipe for supplying a conjugated diolefin or a mixture of acrylonitrile and a compound that generates a conjugated diolefin in the reactor to the inside of the reactor has an outer surface and a liquid supply port (a raw material supply port). Liquid outlet from the supply pipe) Surface roughness representing fine irregularities on the surface is 5
μm or less, more preferably 1 μm
It is more preferable to use those having m or less. When the surface roughness is larger than 5 μm, the insoluble polymer tends to adhere to the raw material supply pipe, and it is difficult to continue a stable continuous production reaction for a long time.

The method for reducing the roughness of the outer surface of the raw material supply pipe and the surface of the liquid supply port is not particularly limited. Generally, mechanical polishing such as buff polishing, belt polishing, barrel polishing, electrolytic polishing, or the like, or It can be achieved by using these together.

The range in which the surface finishing of the raw material supply pipe is required is that the outer surface of the raw material supply pipe in the reactor must be finished to the above degree. In addition, the inner surface must have at least the inner surface portion of the range in which the raw material supply pipe is immersed in the reaction liquid, and more preferably the entire inner surface of the raw material supply pipe in the reactor has the surface finish as described above. That is being done.

Further, in the present invention, a conjugated diolefin or a mixed solution of acrylonitrile and a compound which generates a conjugated diolefin in a reactor can be used by using the raw material supply pipe.
The reaction material is supplied by discharging in the liquid phase part in the reactor,
Let react.

[0028] The above-mentioned problems, which could not be achieved by the prior art, are not accompanied by the formation of a polymer in the raw material supply pipe or on the inner wall of the reactor when the raw material is supplied to the liquid phase portion in the reactor. At the same time as suppressing, it is possible to suppress the production of polymer in the reactor gas phase top plate, in performing the continuous production of conjugated diolefin and acrylonitrile adducts stable for a long time, extremely This is an important requirement. On the other hand, the reaction product is usually taken out from the lower part of the reactor.

In this case, the mixture of acrylonitrile and a conjugated diolefin as a raw material or a compound that generates a conjugated diolefin in a reactor is supplied to the outer surface of the raw material supply pipe and the surface of the liquid supply port without following the present invention. When a material having a roughness greater than 5 μm is used and supplied into a liquid phase in a reactor to supply a reaction raw material and cause a reaction, a polymer is easily attached to the raw material supply pipe. It is difficult to continuously produce an adduct of conjugated diolefin and acrylonitrile which is easy to block the supply pipe and stable for a long time.

Also, a mixture of acrylonitrile and a conjugated diolefin as a raw material or a compound that generates a conjugated diolefin in a reactor is discharged in a gas phase portion in the reactor.
When the reaction is carried out by dropping to the liquid phase and supplying the raw material, the generation and adhesion of insoluble polymer on the raw material supply pipe and the inner wall of the reactor can be suppressed, but the continuous In the reaction, the polymer adhered to the gas phase top plate in the reactor, and the operation of instruments such as an attached pressure gauge and valves could be hindered. It is difficult to continuously produce an adduct of a conjugated diolefin and acrylonitrile.

In the present invention, the reaction between conjugated diolefin or a compound that generates conjugated diolefin in a reactor and acrylonitrile suppresses the by-product of the polymer in the reaction solution and usually suppresses the formation of the polymer. The reaction is carried out in the presence of a compound. As the compound that suppresses the formation of a polymer, a wide range of compounds such as those used in a generally known Diels-Alder reaction can be used. Among these, in the present invention, it is particularly preferable to use an N-nitrosamine compound or a p-phenylenediamine compound. These are used when acrylonitrile is reacted with a conjugated diolefin or a compound that generates a conjugated diolefin in a reactor.
This is a compound that can extremely effectively prevent the generation of a soluble polymer that is a precursor of the generation of an insoluble polymer.

The above-mentioned N-nitrosamine compound includes N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosomethylethylamine, N-nitrosodiphenylamine, N-nitrosobenzylaniline, and 4-nitroso-N, N-dimethyl Aniline and the like are preferably used. As the p-phenylenediamine compound, N-phenyl-N′-isopropyl-p-phenylenediamine is preferably used. These compounds may be used alone or in combination of two or more.

The amount of the compound which suppresses the production of the polymer is usually in the range of 0.003 to 1% by weight based on the total amount of the conjugated diolefin which is the reactant or the compound which generates the conjugated diolefin in the reactor and acrylonitrile. , More preferably in the range of 0.005 to 0.3% by weight. These compounds that suppress the formation of the polymer may be present in the reaction solution when the reaction is carried out.For example, they may be added in advance to the conjugated diolefin as a raw material or a compound that generates a conjugated diolefin in a reactor. Or a method of adding to a mixture of acrylonitrile and a conjugated diolefin or a compound generating a conjugated diolefin in a reactor.

In the present invention, the reaction temperature of the conjugated diolefin or the compound generating conjugated diolefin in the reactor with acrylonitrile is in the range of 180 to 220 ° C., more preferably 180 to 200 ° C. When the reaction temperature is lower than 180 ° C., although it is possible to suppress the formation of a soluble polymer, the yield of an adduct of the obtained conjugated diolefin and acrylonitrile decreases, and the reaction solution contains A large amount of unreacted substances also remains. Also 2
When the reaction is carried out at a temperature higher than 20 ° C., a soluble polymer is remarkably started to be formed in the reaction solution. Therefore, the reaction is preferably carried out at a temperature within the above-mentioned range.

In the present invention, the reaction between the conjugated diolefin as a raw material and acrylonitrile is theoretically a reaction of 1 mol of acrylonitrile per 1 mol of conjugated diolefin. On the other hand, the reaction is preferably carried out in the range of 1 to 1.5 mol of acrylonitrile. If the amount is less than 1 mol, the amount of by-products increases, and if it exceeds 1.5 mol, a large amount of unreacted acrylonitrile remains after the reaction, and both are undesirably complicated in the purification operation. Therefore, when dicyclopentadiene is used as a compound that generates a conjugated diolefin in a reactor, it is preferable to carry out the reaction in the range of 2 to 3 mol of acrylonitrile per 1 mol of dicyclopentadiene.

The reaction time depends on the reaction temperature, but it is important to obtain an adduct of conjugated diolefin or a compound generating conjugated diolefin in the reactor with acrylonitrile in good yield, and considering the productivity. , Usually 0.1-6
Time range. In addition, if necessary, the reaction time may be shortened or further increased.

In carrying out the method of the present invention, the reaction is:
A mixture of acrylonitrile and a conjugated diolefin as a raw material or a compound that generates a conjugated diolefin in the reactor is continuously supplied to the reactor using a metering pump or the like,
At the same time, the reaction is carried out in a continuous system in which a gas inert to the reaction is fed to adjust the pressure. However, using an inert gas for the reaction and increasing the pressure for the reaction is also effective in a batch system. When the reaction is performed in a continuous manner, the conjugated diolefin as the raw material or the compound that generates the conjugated diolefin in the reactor and acrylonitrile are not separate, but they are mixed in advance, and then the mixture is supplied to the reactor.

[0038]

The usefulness of the present invention will be described in more detail with reference to the following examples.

Example 1 An inner wall of a reactor, a raw material supply pipe (SUS)
−304) and the surfaces of the stirring blades and the stirring shaft are electropolished to a surface roughness of 0.4.
A 150-liter pressure-resistant stainless steel reactor equipped with a stirrer and jacket and having a size of 150 μm was used. FIG. 1 shows a main part of the reactor. FIG. 3 shows the surface roughness of the inner wall of the reactor in a geometrical form.

First, before starting the reaction, the reactor was charged with 100 liters of cyanonorbornene, and the stirrer was rotated at 120 rpm.
While stirring at the number of revolutions, the heating medium oil heated by the electric heater was passed through the reactor jacket, and the temperature of the liquid in the reactor was reduced to 180.
The temperature was raised to ° C.

Next, dicyclopentadiene and acrylonitrile were mixed at a molar ratio of 1: 2.5, and N-nitrosodiphenylamine was added to this mixed solution to a concentration of 0.1% by weight to obtain a raw material liquid, which was then subjected to a metering pump. The raw material was continuously supplied from the supply pipe to the liquid phase portion in the reactor. The residence time is
The supply flow rate was adjusted to 1.2 hours. During the reaction, the volume of the gas phase in the upper layer of the reaction solution is 30% of the total volume in the reactor.
% While maintaining the liquid level in the reactor. At the same time, the pressure in the reactor was 8 kg / cm ² · G
The pressure was adjusted by feeding nitrogen gas so that the pressure became constant, and the liquid temperature was further adjusted so as to maintain 190 ° C. to continuously carry out the reaction.

As a result, cyanonorbornene was continuously obtained with an average yield of 90 mol% based on cyclopentadiene obtained by decomposing dicyclopentadiene as a raw material.
The amount of the soluble polymer produced in the reaction solution immediately after the start of the reaction was 0.002% by weight, but the value hardly changed even after 90 days from the start of the continuous operation. Therefore, at this time, the reaction was stopped once, the raw material supply pipe was removed, and the inspection was carried out. As a result, no adhesion of the insoluble polymer was confirmed. Further, when the condition of the gas phase top plate in the reactor was confirmed using a fiberscope, no adhesion of insoluble polymer was confirmed.

Next, the raw material supply pipe was restored, the reaction was started again, and the continuous operation was continued. However, even after 180 days from the start of the continuous operation, the amount of the soluble polymer produced was the same as immediately after the start of the reaction. Almost never changed. After 200 days, the operation was stopped, the reactor was dismantled, and the gas phase top plate, raw material supply pipe, liquid phase inner wall, reaction liquid outlet, and stirrer in the reactor were examined in detail. As a result, no adhesion of the insoluble polymer was observed.

The reaction solution was analyzed by gas chromatography, and the amount of the soluble polymer produced was determined by gel permeation chromatography after diluting the reaction solution with tetrahydrofuran.

Example 2 The inner wall of the reactor, the inner and outer walls of the raw material supply pipe, the surfaces of the stirring blades and the stirring shaft were electropolished to a surface roughness of 2.1 μm.
m, a pressure-resistant stainless steel reactor with an internal volume of 150 liters equipped with a stirrer and a jacket was used. The main parts of the reactor are the same as in FIG. FIG. 4 shows the surface roughness of the inner wall of the reactor in a geometrical form.

First, before starting the reaction, the reactor was charged with 100 liters of cyanonorbornene, and a heating medium oil heated by an electric heater was passed through the reactor jacket while stirring at a rotation speed of 120 rpm. The temperature inside was raised to 185 ° C.

Next, dicyclopentadiene and acrylonitrile were mixed at a molar ratio of 1: 2.5, and N-nitrosodiphenylamine was added to this mixture to a concentration of 0.1% by weight to obtain a raw material liquid, which was then subjected to a metering pump. The raw material was continuously supplied from the supply pipe to the liquid phase portion in the reactor. The residence time is
The supply flow rate was adjusted to 1.2 hours. During the reaction, the volume of the gas phase in the upper layer of the reaction solution is 30% of the total volume in the reactor.
% While maintaining the liquid level in the reactor. At the same time, the pressure in the reactor was 8 kg / cm ² · G
The pressure was adjusted by feeding nitrogen gas so that the temperature became constant, and the liquid temperature was adjusted so as to maintain 195 ° C., and the reaction was continuously performed.

As a result, cyanonorbornene was continuously obtained with an average yield of 93 mol% based on cyclopentadiene obtained by decomposition of dicyclopentadiene as a raw material.
The amount of the soluble polymer produced in the reaction solution immediately after the start of the reaction was 0.003% by weight, but the value hardly changed even after 90 days from the start of the continuous operation. Therefore, at this time, the reaction was stopped once, the raw material supply pipe was removed, and the inspection was carried out. As a result, no adhesion of the insoluble polymer was confirmed. Further, when the condition of the gas phase top plate in the reactor was confirmed using a fiberscope, no adhesion of insoluble polymer was confirmed.

Next, the raw material supply pipe was restored, and instead of adding N-nitrosodiphenylamine, 0.01% by weight of N-phenyl-N'-isopropyl-p-phenylenediamine was added to the raw material mixture. Was adjusted to maintain 185 ° C., and the residence time was set to 5 hours, the reaction was started again, and continuous operation was continued.

As a result, cyanonorbornene was continuously obtained with an average yield of 91 mol% based on cyclopentadiene obtained by decomposition of dicyclopentadiene as a raw material.
The amount of soluble polymer produced in the reaction solution immediately after the restart of the reaction was 0.01% by weight, but the value hardly changed even after 180 days from the start of continuous operation. After 200 days, the operation was stopped, the reactor was dismantled, and the gas phase top plate, raw material supply pipe, liquid phase inner wall, reaction liquid outlet, and stirrer in the reactor were examined in detail. As a result, no adhesion of the insoluble polymer was observed.

Comparative Example 1 The procedure of Example 1 was repeated except that the inner and outer surfaces of the raw material supply pipe had a roughness of 13 μm. FIG. 5 shows the surface roughness of the inner and outer surfaces of the raw material supply pipe in a geometric form.

As a result, cyanonorbornene was continuously obtained with an average yield of 90 mol%. In this example, the amount of soluble polymer generated in the reaction solution immediately after the start of the reaction is
It was 0.005% by weight, and its value hardly changed even after 60 days from the start of continuous operation, but the supply of raw materials began to hinder gradually, and the operation was stopped after 90 days. When the reactor was disassembled and examined, no insoluble polymer was found to adhere to the gas phase top plate, liquid phase inner wall, reaction liquid outlet, and stirrer inside the reactor, but the inside of the raw material supply pipe was In particular, it was confirmed that a large amount of insoluble polymer had adhered, particularly near the raw material outlet from the pipe, and the supply port was in a state just before closing.

Comparative Example 2 The same operation as in Example 1 was carried out except that the raw material supply pipe was shortened and the raw material liquid was continuously supplied to the gas phase in the upper part of the reactor. FIG. 2 shows a main part of the reactor.

As a result, cyanonorbornene was continuously obtained with an average yield of 90 mol%. In this example, the amount of soluble polymer generated in the reaction solution immediately after the start of the reaction was 0.
0015% by weight, and the value hardly changed even after 90 days from the start of continuous operation. Then, at this point, the reaction was stopped, the raw material supply pipe was removed, and inspection was performed.As a result, no adhesion of insoluble polymer was confirmed, but the state of the gas phase top plate in the reactor was confirmed using a fiber scope. However, it was confirmed that a polymer was attached to this portion. So, when the reactor was dismantled and examined,
No insoluble polymer adhered to the inner wall of the liquid phase, the outlet of the reaction solution, and the stirrer.However, the insoluble polymer in the form of a film adhered to the gas phase top plate in the reactor. Was observed.

Example 3 Using the same reactor as in Example 1, before starting the reaction,
The reactor was charged with 100 liters of cyanocyclohexene, and while stirring the stirrer at a rotation speed of 120 rpm, a heating medium oil heated by an electric heater was passed through the reactor jacket to raise the liquid temperature in the reactor to 180 ° C. Warmed.

Next, 1,3-butadiene and acrylonitrile were mixed at a molar ratio of 1: 1.2 in a pressurized container, and N-nitrosodiphenylamine was added to this mixture to a concentration of 0.1% by weight. A liquid was continuously supplied from a raw material supply pipe to a liquid phase portion in the reactor by a metering pump to cause a reaction.
The supply flow rate was adjusted so that the residence time was 1.5 hours.
During the reaction, the liquid level in the reactor was maintained such that the volume of the gas phase in the upper layer of the reaction solution was 30% of the total volume in the reactor. At the same time, the pressure was adjusted by supplying nitrogen gas so that the pressure inside the reactor became 70 kg / cm ² · G, and further, the liquid temperature was adjusted to maintain 205 ° C, and the reaction was continuously performed. I let you.

As a result, cyanocyclohexene was continuously obtained with an average yield of 88 mol% based on 1,3-butadiene as a raw material. After 60 days of continuous operation from the start of the reaction, the operation was stopped, the reactor was dismantled, and the gas phase top plate in the reactor was removed.
A detailed examination of the raw material supply pipe, the inner wall of the liquid phase, the outlet of the reaction liquid, the stirrer, and the like revealed no adhesion of any insoluble polymer.

Example 4 Using the same reactor as in Example 1, before starting the reaction,
Fill the reactor with 100 liters of methylcyanocyclohexene and, while stirring the stirrer at a rotation speed of 120 rpm, pass a heating medium oil heated by an electric heater through the reactor jacket to raise the liquid temperature in the reactor to 180 ° C. The temperature rose.

Next, isoprene and acrylonitrile were mixed at a molar ratio of 1: 1.3 in a vessel cooled to 10 ° C., and N-nitrosodiphenylamine was added to this mixture to a concentration of 0.1% by weight. The mixture was continuously supplied from a raw material supply pipe to a liquid phase portion in the reactor by a metering pump to cause a reaction. The supply flow rate was adjusted so that the residence time was one hour. During the reaction, the liquid level in the reactor was maintained such that the volume of the gas phase in the upper layer of the reaction solution was 30% of the total volume in the reactor. At the same time, the pressure inside the reactor is 50 kg / cm ² · G
The pressure was adjusted by feeding nitrogen gas so that the pressure became constant, and the liquid temperature was further adjusted so as to maintain 205 ° C. to continuously carry out the reaction.

As a result, methylcyanocyclohexene was continuously obtained with an average yield of 86 mol% based on the raw material isoprene. After 60 days of continuous operation from the start of the reaction, the operation is stopped, the reactor is disassembled, and the gas phase top plate, raw material supply piping, liquid phase inner wall, reaction liquid outlet, stirrer, etc. are detailed in the reactor. As a result, no adhesion of the insoluble polymer was confirmed.

[0061]

According to the method for producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile in the present invention, not only can the formation of an insoluble polymer in a reaction solution be suppressed, but also can be achieved by the prior art. It is possible to remarkably prevent the phenomenon that the polymer adheres to the top plate in the gas phase portion in the reactor, which has been difficult, and in particular, it is possible to perform a long-term continuous production operation without any trouble.

Accordingly, the method according to the present invention is more advantageous than the conventionally known method, especially in the case of industrially producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile, and is a more advantageous method. It can be said that there is.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating states and main parts inside a reactor and the like in Examples 1 and 2 and Comparative Example 1.

FIG. 2 is an explanatory diagram illustrating a state and a main part of a reactor and the like in Comparative Example 2.

FIG. 3 shows inner and outer surface roughness of a raw material supply pipe in Example 1 and Comparative Example 2, and Example 1 and Comparative Examples 1 and 2.
4 is a chart showing the surface roughness of the inner wall of the reactor in a geometrical form.

FIG. 4 is a chart showing the surface roughness of the inner surface and outer surface of the raw material supply pipe and the surface roughness of the inner wall of the reactor in a geometrical form in Example 2.

FIG. 5 is a chart showing the surface roughness of the inner surface and the outer surface of the raw material supply pipe in Comparative Example 1 in a geometrical form.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Raw material liquid 2 ... Metering pump 3 ... Reactor 4 ... Reaction liquid 5 ... Jacket 6 ... Heat medium oil 7 ... Automatic control valve 8 ... Conjugated diolefin Diels-Alder adduct of acrylonitrile and acrylonitrile A: Stirrer P: Pressure gauge T: Thermometer L: Differential pressure level gauge S: Safety valve

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akio Numa 1900 Togo, Mogo-shi, Chiba Mitsui Chemicals Co., Ltd. (72) Inventor Hiroharu Kageyama 1900 Togo, Togo, Mobara-shi, Chiba Mitsui Chemicals Co., Ltd. (72) Invention Person Jun Orukawa 1900 Togo, Mobara-shi, Chiba Prefecture Mitsui Chemicals Co., Ltd. (72) Inventor Hisahiro Kato 1900, Togo, Togo, Mobara-shi, Chiba Mitsui Chemicals Co., Ltd. BD21 QN30

Claims (14)

[Claims] 1. A tank-type reactor, wherein a gas phase portion is present in the reactor, and the pressure is increased by using an inert gas for the reaction.
A conjugated diolefin or a mixture of acrylonitrile and a compound that generates a conjugated diolefin in a reactor is supplied to the reactor to be reacted, and when producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile, The inner wall of the vessel and the outer surface and the liquid supply port of the raw material supply pipe for supplying the above mixed liquid in the reactor have a surface roughness of 5 μm or less, and the mixed liquid is used in the liquid phase in the reactor. A process for producing a Diels-Alder adduct of a conjugated diolefin and acrylonitrile. 2. The method according to claim 1, wherein the reaction temperature is 180 to 220 ° C.
The manufacturing method as described. 3. The process according to claim 1, wherein the volume of the gas phase is 10 to 50% of the total internal volume of the reactor. 4. The method according to claim 1, wherein the pressure during the reaction is 6 to 80 kg / cm ² · G. 5. The method according to claim 1, wherein the gas inert to the reaction is nitrogen, argon, helium, methane, ethane, propane, n-butane or isobutane. 6. The compound that generates a conjugated diolefin is dicyclopentadiene, and the pressure during the reaction is 6 to 30 kg /
The method according to claim 1, wherein the value is cm ² · G. 7. The method according to claim 6, wherein the pressure during the reaction is 6 to 10 kg / cm ² · G. 8. The conjugated diolefin is butadiene,
The method according to claim 1, wherein the pressure during the reaction is 50 to 80 kg / cm ² · G. 9. The method according to claim 8, wherein the gas inert to the reaction is nitrogen, argon, helium, methane or ethane. 10. The conjugated diolefin is isoprene and the pressure during the reaction is 30 to 60 kg / cm ² · G.
The manufacturing method as described. 11. The method according to claim 10, wherein the gas inert to the reaction is nitrogen, argon, helium, methane, ethane or propane. 12. An N-nitrosamine compound or a mixture of acrylonitrile and a conjugated diolefin which has been mixed in advance or a compound which generates a conjugated diolefin in a reactor.
2. The method according to claim 1, wherein a p-phenylenediamine compound is present. 13. The method according to claim 13, wherein the N-nitrosamine compound is N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosomethylethylamine, N-nitrosodiphenylamine, N-nitrosobenzylaniline, or 4-nitroso-N, N
-The production method according to claim 12, which is dimethylaniline. 14. The method according to claim 12, wherein the p-phenylenediamine compound is N-phenyl-N′-isopropyl-p-phenylenediamine.