JP5040435B2 - Method for producing xylylenediamine - Google Patents

Description

  The present invention relates to a method for producing xylylenediamine useful as a resin curing agent and its raw material, a polyamide resin, an intermediate raw material for isocyanate, and the like.

  In recent years, high purity xylylenediamine having a low cyanobenzylamine content has been demanded, particularly as an intermediate raw material for isocyanate. In such applications, high purity xylylenediamine having a cyanobenzylamine content of 0.02% by weight or less is required. Therefore, a method for industrially advantageously producing high purity xylylenediamine having a low cyanobenzylamine content is required.

  Xylylenediamine is known to be obtained by catalytic hydrogenation of phthalonitriles in the presence of liquid ammonia and / or an organic solvent (see, for example, Patent Document 1 and Patent Document 2). Since phthalonitriles are compounds having a relatively high melting point, it is essential to use liquid ammonia or an organic solvent. In particular, it has been conventionally known that liquid ammonia has an action of suppressing an undesirable side reaction in which an imine intermediate generated in a hydrogenation reaction and a nitrile group react to generate an oligomer or the like. Therefore, a large amount of liquid ammonia is often used.

  Furthermore, this catalytic hydrogenation reaction is a sequential reaction from phthalonitriles to cyanobenzylamine and from cyanobenzylamine to xylylenediamine, so that cyanobenzylamine always remains in the reaction system in a trace amount.

  When the catalytic hydrogenation reaction is performed by a single-pass flow reaction or batch reaction, it is necessary to use a large amount of liquid ammonia in order to suppress side reactions as described above. Therefore, the apparent reaction rate decreases due to a decrease in the substrate concentration, and cyanobenzylamine tends to remain. Patent Document 3 describes a cyclic reaction system in which a part of a reaction solution is extracted, mixed with newly supplied raw materials, and reacted again in order to reduce the amount of solvent used. However, even in this case, cyanobenzylamine tends to remain because the substrate concentration decreases.

  Cyanobenzylamine is an unstable substance that, when left alone, is colored and decomposes to release ammonia and form a viscous polymer. Further, even when contained in xylylenediamine, the same behavior is exhibited, and generally the boiling point difference from the corresponding xylylenediamine is small, so that separation by ordinary distillation is difficult.

  As a method for producing xylylenediamine having a low cyanobenzylamine content, crude xylylenediamine obtained by catalytically hydrogenating phthalonitriles in the presence of liquid ammonia and / or an organic solvent and then removing the solvent ( A method of treating an xylylenediamine having a high cyanobenzylamine content with an alkali (see, for example, Patent Document 4), or a catalyst containing an oxide of iron or iron and chromium in the presence of water. There is known a method of bringing it into contact (for example, see Patent Document 5).

  However, the alkali treatment method can obtain xylylenediamine having a low cyanobenzylamine content, but waste liquid containing alkali is discharged. This waste liquid is subjected to activated sludge treatment or incineration after neutralization, but has a difficulty in its treatment because it contains alkali. The method of bringing crude xylylenediamine into contact with a catalyst containing iron oxide or iron and chromium oxide in the presence of water requires an additional step of distilling off the water used in the reaction, such as industrially. It is disadvantageous. In either case, the intermediate cyanobenzylamine is converted into a high-boiling substance and removed, which is inefficient.

  Patent Document 6 discloses a step (a) in which a hydrogenation reaction is allowed to proceed until the nitrile conversion rate is in a range of 90 mol% or more and less than 99.9 mol%, and a nitrile at a reaction temperature higher by 10 ° C. or more than step (a). In two steps of step (b) in which the hydrogenation reaction proceeds until the conversion rate is higher than the conversion rate in step (a) and reaches 99.5 mol% or more, phthalonitriles are hydrogenated in the presence of a solvent. It has been shown that high-purity xylylenediamine having a low cyanobenzylamine content can be produced with good yield.

This method is one method for obtaining high-purity xylylenediamine having a low cyanobenzylamine content. However, an undesirable side reaction due to the high reaction temperature occurs in step (b), and in order to suppress this, it is necessary to adjust the nitrile conversion rate and reaction temperature in step (a). There was a lot of trouble. In addition, since the hydrogenation reaction is always performed in the presence of the reaction solvent, the concentration of the substrate is lowered, and a considerable amount of catalyst is required.
Japanese Patent Publication No. 51-24494 JP 2002-105035 A International Publication No. 2005/026098 Pamphlet Japanese Patent Publication No. 45-14777 Japanese Patent Publication No.57-27098 JP 2004-292435 A

  The present invention provides a method for industrially advantageously producing a high-quality xylylenediamine having a low cyanobenzylamine content.

The present inventors perform a catalytic hydrogenation reaction (catalytic hydrogenation treatment) of phthalonitriles with liquid ammonia or a mixed solvent composed of liquid ammonia and an organic solvent, and then remove at least the liquid ammonia to obtain a reaction product. Once obtained, the reaction product obtained is subjected to catalytic hydrogenation treatment again under mild conditions in the presence of a catalyst and then purified by distillation to obtain high-quality xylylenediamine having a low cyanobenzylamine content. It was found that the product can be obtained with good yield.
That is, the present invention includes the following sequential steps:
(1) The first catalytic hydrogenation treatment is performed on phthalonitriles and liquid ammonia or a liquid ammonia and an organic solvent, and the liquid ammonia or a liquid mixture containing the liquid ammonia and the organic solvent is 80% by weight or more. And hydrogenating the phthalonitriles to obtain a reaction product (A),
(2) removing liquid ammonia in the reaction product (A) to obtain a reaction product (B);
(3) subjecting the reaction product (B) to a second catalytic hydrogenation to hydrogenate cyanobenzylamine to obtain a reaction product (C); and (4) distilling the reaction product (C). And a process for producing xylylenediamine, which comprises the step of purifying xylylenediamine.

  In the present invention, a high-quality xylylenediamine having a very low content of cyanobenzylamine is obtained. Further, cyanobenzylamine can be removed under mild conditions, the amount of catalyst can be reduced, and the construction cost of the apparatus can be reduced. Furthermore, in the production method of the present invention, the water removal step is not necessary.

The production method of the present invention will be described separately for each step.
Process (1)
In step (1), the first contact is made with phthalonitrile and liquid ammonia or liquid ammonia and an organic solvent, and the liquid ammonia or the liquid ammonia and the liquid mixture containing the organic solvent are 80% by weight or more. This is a step of performing a hydrogenation treatment and hydrogenating the phthalonitriles to obtain a reaction product (A).

The phthalonitriles used in the present invention refer to compounds in which two nitrile groups are substituted on the benzene ring. Further, in addition to the nitrile group, halogen atoms such as fluorine and chlorine, methyl groups, ethyl groups, etc. Also included are compounds in which an alkyl group or phenyl group is substituted.
Such phthalonitriles include o-phthalonitrile, isophthalonitrile, terephthalonitrile, 2-chlorophthalonitrile, 5-methylisophthalonitrile, 4-methylisophthalonitrile, 5-phenylisophthalonitrile, and the like. Can be mentioned.
Of these, isophthalonitrile, terephthalonitrile, 4- and 5-methylisophthalonitrile are preferable, and isophthalonitrile and terephthalonitrile are more preferable.

In the present invention, the mixture is subjected to a first catalytic hydrogenation treatment, and the above phthalonitriles are hydrogenated to obtain a reaction product (A). As the solvent, liquid ammonia or a mixed solvent composed of liquid ammonia and an organic solvent is used.
As an organic solvent when used as a mixed solvent, phthalonitriles are dissolved, and low-boiling aromatic hydrocarbons and saturated aliphatic hydrocarbons are preferable. Specifically, benzene, toluene, xylenes, mesitylene, Examples include pseudocumene, hexane, and cyclohexane. Among these, particularly industrially, xylenes that do not increase the number of handling compounds are advantageous.
The weight ratio between the liquid ammonia and the organic solvent can be arbitrarily selected, but the amount of the liquid ammonia with respect to the phthalonitriles is preferably equal to or more than the same. By increasing the ratio of the organic solvent, the reaction pressure can be reduced. However, when the amount of liquid ammonia is too small, an undesirable side reaction may occur and the reaction yield may be reduced.

  As the catalyst for the catalytic hydrogenation reaction of phthalonitriles, known supported metal catalysts, non-supported metal catalysts, Raney catalysts, noble metal catalysts and the like can be used. In particular, a catalyst containing nickel, cobalt, or palladium is preferably used.

The first catalytic hydrotreating method can be batch or continuous.
Examples of the batch type include a complete mixing type system in which a Raney metal powder catalyst of nickel or cobalt is placed in a tank reactor.
As a continuous type, a tubular reactor is used, a molded catalyst is used as a fixed bed, and an irrigation type continuous reactor that supplies the mixed solution (raw material solution) and hydrogen gas in parallel from the top of the reactor is used. Can be illustrated. This method is industrially simple and preferable. In addition, when using an irrigation type continuous reactor in which the raw material solution and hydrogen gas are supplied in parallel from the upper part of the reactor, even with a single-pass method in which the reaction is performed by circulating only the raw material solution and hydrogen gas in advance, A circulation system in which a part of the reactor outlet liquid and hydrogen gas are allowed to flow together may be used.

In the first catalytic hydrogenation treatment, liquid ammonia or a mixed solvent composed of liquid ammonia and an organic solvent is preferably used in an amount of 80 weight percent or more, more preferably 90 weight percent or more based on the mixed solution.
If the amount of liquid ammonia or a mixed solvent composed of liquid ammonia and an organic solvent is less than 80 percent by weight, a by-product is generated due to an undesirable reaction, and the reaction yield decreases.
The ratio of the liquid ammonia or a mixed solvent composed of liquid ammonia and an organic solvent to the mixed solution is calculated from the charged composition of the raw material phthalonitriles and the solvent in the case of batch reaction.
In the case of the flow type, it is calculated from the composition of the raw material phthalonitrile and the solvent at the reactor inlet. That is, in the case of a circulation method in which a part of the reaction product (A) is returned to the reactor inlet by a flow equation, the calculation is made from the composition of the newly fed raw material solution and the circulated reaction product (A). Is done.

The amount of catalyst used varies depending on the type of catalyst and reaction conditions, but when batchwise, the amount is preferably 0.1 to 200 parts by weight, more preferably 100 parts by weight of the initial charge of raw material phthalonitriles. Is 0.2 to 100 parts by weight. When performing by a fixed bed system, it is 0.1-20000 weight part with respect to the feed rate of 1 weight part / hour of raw material phthalonitrile, More preferably, it is 0.2-7000 weight part.
The treatment temperature of the first catalytic hydrogenation treatment is preferably 20 ° C to 200 ° C, more preferably 30 to 180 ° C, and further preferably 40 to 150 ° C. Further, the hydrogen partial pressure is preferably 3.0 to 20.0 MPa, and more preferably 4.0 to 15.0 MPa.
The degree of hydrogenation reaction of phthalonitriles in step (1) is obtained in step (2) because hydrogen gas and catalyst are removed and hydrogenation reaction does not proceed in step (2) described later. It can be estimated by analyzing the composition of the reaction product (B). The residual amount of phthalonitrile contained in the reaction product (B) is preferably 100 ppm or less, and more preferably 10 ppm or less, which is the analytical detection limit. When phthalonitrile is further present, the activity of the catalyst used in the second catalytic hydrotreatment may be deteriorated. That is, the degree of hydrogenation reaction of phthalonitriles in step (1) means that the hydrogenation reaction is such that 99.99% or more of the starting phthalonitriles are subjected to the reaction.

Process (2)
Step (2) is a step of obtaining reaction product (B) by removing liquid ammonia in reaction product (A).
Examples of the method for removing ammonia include a method using dropping pressure and a method for removing by flowing an inert gas such as nitrogen gas.
When a mixed solvent composed of liquid ammonia and an organic solvent is used in the first catalytic hydrogenation treatment, the liquid ammonia may be removed from the reaction product (A) by the method described above. The necessity of removing the organic solvent can be appropriately selected in consideration of the entire process. Distillation may be performed to remove the organic solvent.

Here, the total amount of xylylenediamine and cyanobenzylamine in the reaction product (B) is preferably 40% by weight or more, more preferably 60% by weight or more, and 80% by weight or more. More preferably. By being 40% by weight or more, the next second catalytic hydrogenation treatment can be performed under mild conditions.
The weight ratio of cyanobenzylamine to xylylenediamine in the reaction product (B) is preferably 0.01 or less. By being 0.01 or less, the quality of the xylylenediamine obtained can be improved.

The amount of liquid ammonia in the reaction product (B) is preferably 1 weight percent or less.
If the amount of liquid ammonia is 1 percent by weight or less, it is possible to prevent an increase in the partial pressure of the reaction product (B), so that a higher pressure reactor is unnecessary in the second catalytic hydrotreatment. Become. In addition, when the residual amount of liquid ammonia is small, the required second catalytic hydrogenation treatment is possible, for example, the required amount of catalyst is reduced.

Process (3)
Step (3) is a step of subjecting the reaction product (B) to a second catalytic hydrogenation to hydrogenate cyanobenzylamine to obtain a reaction product (C).
By the second catalytic hydrogenation treatment, cyanobenzylamine in the reaction product (B) is hydrogenated to xylylenediamine. Therefore, the cyanobenzylamine content can be further reduced by this step.

  Examples of the catalyst that can be used for the second catalytic hydrogenation treatment include a supported metal catalyst, a non-supported metal catalyst, a Raney catalyst, and a noble metal catalyst. In particular, a catalyst in which nickel and / or cobalt is supported on a support is preferable, and a catalyst in which nickel is supported on a support is particularly preferable. As the carrier, diatomaceous earth, silicon oxide, alumina, silica-alumina, titanium oxide, zirconium oxide, carbon and the like are used. In the case of a catalyst in which nickel and / or cobalt is supported on a support, the nickel and / or cobalt content is preferably 10 to 80%, more preferably 30 to 70%, and even more preferably 40 to 60%.

  The second catalytic hydrogenation treatment can be performed batchwise or continuously. Examples of the batch type include a complete mixing type in which a Raney metal powder catalyst of nickel or cobalt is put into a tank reactor and reacted. As the continuous type, a tubular reactor is used, and a method using an irrigated type continuous reactor in which a molded catalyst is used as a fixed bed and a raw material (reaction product (B)) and hydrogen gas are supplied from the upper part of the reactor. This method is simple and preferable.

  Examples of the material used for the catalytic hydrogenation reactor used in each of the first catalytic hydrogenation treatment and the second catalytic hydrogenation treatment include carbon steel and stainless steel such as SUS304, SUS316, and SUS316L. Moreover, the container which gave the glass lining process to the iron and stainless steel used for a normal pressure-resistant container can also be used.

  The treatment temperature of the second catalytic hydrogenation treatment is appropriately determined, but is preferably in the range of 30 ° C to 150 ° C, and more preferably in the range of 40 ° C to 100 ° C. If it is 30 degreeC or more, the remarkable fall of the conversion of a cyano benzylamine can be prevented. If it is 150 degrees C or less, it will prevent that the nuclear hydrogenation and deamination of xylylenediamine contained in a large amount in the reaction product (B) proceeds in large quantities, and thermal alteration of xylylenediamine itself. Can also prevent.

  In the second catalytic hydrogenation treatment, the hydrogen partial pressure is appropriately determined, but is usually preferably in the range of 0.1 to 10 MPa, more preferably in the range of 0.5 to 8 MPa, and 1 to 4 MPa. More preferably, it is in the range. If it is 0.1 Mpa or more, the remarkable fall of the conversion rate of a cyano benzylamine can be prevented. If it is 10 MPa or less, it is possible to prevent a large amount of nuclear hydrogenation and deamination of xylylenediamine contained in a large amount in the reaction product (B).

When the second catalytic hydrotreatment is performed in a fixed bed continuous flow system, the flow rate of the raw material entering the hydrogenation reactor is determined in a timely manner. The liquid hourly space velocity (LHSV) is ^preferably in the range of 0.1h ^-1 ~10h ^-1, and more preferably in a range of from 0.1h ^-1 ~3.0h -1. If it is 0.1 h ⁻¹ or more, the flow rate does not become too slow, so that the amount that can be processed per hour is prevented from being extremely reduced, which is industrially advantageous. Moreover, the progress of hydrogenolysis of xylylenediamine contained in a large amount in the reaction product (B) can also be prevented. Moreover, if it is 10 h- ¹ or less, the conversion rate of cyanobenzylamine will not become low too much, and sufficient effect can be maintained.

The amount of hydrogen in the second catalytic hydrotreatment is determined in a timely manner. The amount depends on the amount of cyanobenzylamine in the reaction product (B), preferably the gas hourly space velocity (GHSV) of is determined from 500h ^-1 the range from 200h ^-1 following ranges More preferably, it is determined.
The weight ratio of cyanobenzylamine to xylylenediamine after subjecting the reaction product (B) to the second catalytic hydrogenation treatment is preferably 0.00005 or less. If it is 0.00005 or less, the weight ratio of cyanobenzylamine to xylylenediamine after distillation purification is easily 0.00005 or less, which is preferable because high-quality xylylenediamine is obtained.

Step (4)
Step (4) is a step of purifying xylylenediamine by distilling the reaction product (C).

For the distillation, a distillation apparatus such as a packed tower, a plate tower, a flash drum or the like can be used, and the distillation is carried out batchwise or continuously, preferably under reduced pressure. The reaction product (C) obtained after the second catalytic hydrogenation treatment contains both a compound having a lower boiling point and a compound having a higher boiling point than xylylenediamine. In order to remove both of these compounds, distillation purification may be performed using two distillation columns, a low boiling separation distillation column and a high boiling separation distillation column. Alternatively, using a single distillation column, a compound having a lower boiling point than xylylenediamine from the top, a compound having a higher boiling point than xylylenediamine from the bottom, and xylylenediamine from the middle of the distillation column It may be extracted.
In addition, when two distillation columns, a low boiling separation distillation column and a high boiling separation distillation column, are used, the low boiling point compound is first removed in the low boiling separation distillation column and then the xylylenediamine is removed from the top of the high boiling separation distillation column. May be obtained. Alternatively, xylylenediamine may be obtained from the bottom of the high boiling point separation distillation column after removing the high boiling point compound in the high boiling separation distillation column.

  The operating pressure of the distillation column is preferably 1 to 30 kPa, more preferably 1 to 10 kPa. The temperature at the bottom of the distillation apparatus is preferably 80 to 195 ° C, more preferably 100 to 185 ° C.

  According to the production method of the present invention as described above, high-quality xylylenediamine having a very low content of cyanobenzylamine can be obtained. Further, cyanobenzylamine can be removed under mild conditions, the amount of catalyst can be reduced, and the construction cost of the apparatus can be reduced. Furthermore, in the production method of the present invention, the water removal step is not necessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. Gas chromatography was used for composition analysis. A capillary electrophoresis apparatus was used for analysis of the residual ammonia amount.

<Gas chromatography analysis conditions>
Apparatus: Agilent 6890N type GC column: J & D DB-1
GC measurement sample: After diluting each sampling solution with methanol, diphenylmethane was added as an internal standard and measured.

<Residual ammonia content analysis conditions>
Apparatus: Agilent capillary electrophoresis system Measurement sample: measured after dilution of sample with pure water 10 times (detection limit: about 10 ppm)

Example 1
A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was subjected to hydrogen reduction. Thereafter, a mixed solution of isophthalonitrile and liquid ammonia (isophthalonitrile: liquid ammonia = 8.5: 91.5 (weight ratio)) was supplied from above the reaction tube at a rate of 170 g / h, and the reaction pressure was 7.0 MPa. The first catalytic hydrogenation treatment was continuously carried out for 10 days at 70 ° C. while injecting hydrogen gas of 30 NL / h (“N” represents a standard state; hereinafter the same), and the reaction product (A1 ) Was generated.

  After passing the reaction product (A1) through the gas-liquid separator, the liquid phase part is intermittently withdrawn to the receiver, and ammonia is dropped and removed from the gas phase part of the receiver to room temperature and normal pressure. Further, an operation for removing remaining ammonia by flowing nitrogen gas was performed, and the reaction product (B1) was intermittently extracted. All the extracted reaction product (B1) was mixed and analyzed by gas chromatography. Metaxylylenediamine was 93.1% by weight, 3-cyanobenzylamine was 0.6% by weight, 3-methylbenzylamine was 0.02% by weight, and isophthalonitrile was not detected. The remaining components were metaxylylenediamine oligomers and high boiling point polymers not detected by gas chromatography. When the amount of residual ammonia was analyzed separately, it was about 500 ppm.

  A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was reduced with hydrogen. Thereafter, 1800 g of the reaction product (B1) obtained above was supplied from the upper part of the reaction tube at a rate of 75 g / h, and at 80 ° C. while injecting 3 NL / h of hydrogen gas at a reaction pressure of 2.0 MPa, 2 catalytic hydrogenation treatment was performed. After separating the gas and liquid, the reaction product (C1) was extracted and analyzed by gas chromatography. Metaxylylenediamine had a concentration of 93.5% by weight, 3-methylbenzylamine 0.04% by weight, and 3-cyanobenzylamine concentration 0.001% by weight or less.

  The obtained reaction product (C1) was distilled under a reduced pressure of 6 kPa using a distillation column having 10 theoretical plates to obtain metaxylylenediamine purified to a purity of 99.99%. In addition, 3-cyano benzylamine content in the obtained metaxylylene diamine was 0.001 weight% or less.

Example 2
A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was reduced with hydrogen. Thereafter, 1500 g of the reaction product (B1) obtained in Example 1 was supplied from the upper part of the reaction tube at a rate of 150 g / h, and a hydrogen pressure of 3 NL / h was injected at a reaction pressure of 2.0 MPa at 100 ° C. A second catalytic hydrogenation treatment was performed. After separating the gas and liquid, the reaction product (C2) was extracted and analyzed by gas chromatography. The metaxylylenediamine concentration was 93.4% by weight, 3-methylbenzylamine was 0.06% by weight, and 3-cyanobenzylamine concentration was 0.001% by weight or less. The remaining components were metaxylylenediamine oligomers and high boiling point polymers not detected by gas chromatography.

  The obtained reaction product (C2) was distilled in the same manner as in Example 1 to obtain metaxylylenediamine purified to a purity of 99.99 percent. In addition, 3-cyano benzylamine content in the obtained metaxylylene diamine was 0.001 weight% or less.

Example 3
A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was subjected to hydrogen reduction. Thereafter, a mixed liquid of isophthalonitrile, metaxylene and liquid ammonia (isophthalonitrile: metaxylene: liquid ammonia = 6: 10: 84 (weight ratio)) is supplied from above the reaction tube at a rate of 240 g / h to react. The first catalytic hydrogenation treatment was continuously carried out at 70 ° C. for 7 days while injecting 30 NL / h of hydrogen gas at a pressure of 7.0 MPa to generate a reaction product (A3).

  After passing the reaction product (A3) through the gas-liquid separator, the liquid phase part is intermittently withdrawn to the receiver, and ammonia is dropped and removed from the gas phase part of the receiver to room temperature and normal pressure. Further, an operation for removing remaining ammonia by flowing nitrogen gas was performed, and the reaction product (B3) was intermittently extracted. After all of the extracted reaction product (B3) was mixed, meta-xylene was distilled off by a rotary evaporator. The reaction product (B3) after being distilled off was analyzed by gas chromatography. Metaxylylenediamine is 92.8% by weight, 3-cyanobenzylamine is 0.8% by weight, 3-methylbenzylamine is 0.01% by weight, metaxylene is 0.9% by weight, and isophthalonitrile is Not detected. The remaining components were metaxylylenediamine oligomers and high boiling point polymers not detected by gas chromatography. In addition, although the residual ammonia amount was analyzed separately, it was below the detection limit.

  A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was reduced with hydrogen. Thereafter, 1500 g of the reaction product (B3) obtained above was supplied from the top of the reaction tube at a rate of 150 g / h, and at 100 ° C., while 3 NL / h of hydrogen gas was being injected at a reaction pressure of 4.0 MPa. 2 catalytic hydrogenation treatment was performed. After separating the gas and liquid, the reaction product (C3) was extracted and analyzed by gas chromatography. The metaxylylenediamine concentration was 92.9 wt%, 3-methylbenzylamine 0.09 was wt%, and the 3-cyanobenzylamine concentration was 0.001 wt% or less.

  The obtained reaction product (C3) was distilled in the same manner as in Example 1 to obtain metaxylylenediamine purified to a purity of 99.99%. In addition, 3-cyano benzylamine content in the obtained metaxylylene diamine was 0.001 weight% or less.

Example 4
A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was subjected to hydrogen reduction. Thereafter, a mixed solution of isophthalonitrile and liquid ammonia (isophthalonitrile: liquid ammonia = 1: 3 (weight ratio)) was supplied to the reaction tube at a rate of 57.8 g / h. On the other hand, a part of the reaction liquid is extracted from the liquid reservoir installed at the lower part of the reaction tube, and the pressure is increased by a gear pump, and is circulated at a rate of 173.4 g / hr via a liquid mass flow. The above mixture was supplied from the upper part of the reaction tube. The first catalytic hydrogenation treatment was carried out continuously at 70 ° C. for 10 days while injecting 30 NL / h of hydrogen gas at a reaction pressure of 7.0 MPa to produce a reaction product (A4).

  At this time, the amount of liquid ammonia at the reactor inlet (57.8 g / h × 3/4 + 173.4 g / h × 3/4 = 173.4 g / h) is the amount of the mixture of liquid ammonia and isophthalonitrile. It was 92 weight% with respect to (173.4g / h + 57.8g / h * 1/4 = 187.8g / h).

  After passing the reaction product (A4) through the gas-liquid separator, the liquid phase part is intermittently withdrawn to the receiver, and ammonia is dropped and removed from the gas phase part of the receiver to room temperature and normal pressure. Further, an operation for removing remaining ammonia by flowing nitrogen gas was performed, and the reaction product (B4) was intermittently extracted.

  All the extracted reaction product (B4) was mixed and analyzed by gas chromatography. Metaxylylenediamine was 92.8% by weight, 3-cyanobenzylamine was 0.7% by weight, 3-methylbenzylamine was 0.02% by weight, and isophthalonitrile was not detected. The remaining components were metaxylylenediamine oligomers and high boiling point polymers not detected by gas chromatography. When the amount of residual ammonia was analyzed separately, it was about 500 ppm.

  The reaction product (B4) was subjected to a second catalytic hydrogenation treatment under the same conditions as in Example 1, and after separating the gas and liquid, the reaction product (C4) was extracted. When this was analyzed by gas chromatography, the metaxylylenediamine concentration was 93.2% by weight, 3-methylbenzylamine was 0.04% by weight, and the 3-cyanobenzylamine concentration was 0.001% by weight or less. there were.

  The obtained reaction product (C4) was distilled in the same manner as in Example 1 to obtain purified metaxylylenediamine having a purity of 99.99 percent. In addition, 3-cyano benzylamine content in the obtained metaxylylene diamine was 0.001 weight% or less.

Example 5
An autoclave with an inner volume of 5 L with a jacket was purged with nitrogen, and then 30 g of a commercially available nickel catalyst (Ni content 50%) previously reduced at 200 ° C. in a hydrogen stream, 1500 g of an 8.5 wt% liquid ammonia solution of isophthalonitrile. Then, the pressure was increased to 6.0 MPa with hydrogen gas at room temperature. Then, warm water was poured into the jacket while stirring, and the liquid temperature was heated to 80 ° C. Although the autoclave internal pressure rises temporarily with heating, hydrogen absorption begins and the pressure decreases, so hydrogen gas is intermittently supplied to maintain the liquid temperature at 80 ° C. and the internal pressure at 7.0 to 8.0 MPa. Then, the first catalytic hydrogenation treatment was performed. The amount of the catalyst used was 23.5 parts by weight with respect to 100 parts by weight of the initial charge amount of the starting phthalonitriles.

  After the pressure drop in the autoclave is no longer observed, the reaction is continued for 1 hour at a liquid temperature of 80 ° C. Then, water is flowed through the jacket to lower the liquid temperature to room temperature, and then water is flowed through the jacket to normal pressure. Hydrogen gas and a part of ammonia were removed from the gas phase part of the autoclave to obtain a reaction product (A5). After standing for 2 hours, the reaction product (A5) was transferred to another 5 L autoclave while passing through an in-line filter. After the transfer, ammonia was removed while flowing nitrogen gas through the liquid until no increase in pressure occurred at room temperature.

  Thereafter, the liquid in the autoclave was extracted to obtain 130 g of a reaction product (B5). The reaction product (B5) was analyzed by gas chromatography. Metaxylylenediamine was 91.2% by weight, 3-cyanobenzylamine was 0.5% by weight, 3-methylbenzylamine was 0.05% by weight, and isophthalonitrile was not detected. The remaining components were metaxylylenediamine oligomers and high boiling point polymers not detected by gas chromatography. When the amount of residual ammonia was analyzed separately, it was about 300 ppm.

  A tubular vertical hydrogenation reactor having an internal volume of 30 ml was charged with 15 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was subjected to hydrogen reduction. Thereafter, 100 g of the reaction product (B5) obtained above was supplied from the upper part of the reaction tube at a rate of 7.5 g / h, and a hydrogen pressure of 3 NL / h was injected at a reaction pressure of 2.0 MPa at 80 ° C. A second catalytic hydrogenation treatment was performed. After separating the gas and liquid, the liquid was extracted to obtain 80 g of a reaction product (C5). This was analyzed by gas chromatography. The metaxylylenediamine concentration was 91.3 wt%, 3-methylbenzylamine was 0.07 wt%, and the 3-cyanobenzylamine concentration was 0.001 wt% or less.

  The obtained reaction product (C5) was distilled in the same manner as in Example 1 to obtain metaxylylenediamine purified to a purity of 99.99%. In addition, 3-cyano benzylamine content in the obtained metaxylylene diamine was 0.001 weight% or less.

Comparative Example 1
A tubular vertical hydrogenation reactor having an internal volume of 400 ml was charged with 150 g of a commercially available supported nickel catalyst (Ni content 50%), and this catalyst was subjected to hydrogen reduction. Thereafter, a mixed solution of isophthalonitrile and liquid ammonia (isophthalonitrile: liquid ammonia = 1: 3 (weight ratio)) was supplied from above the reaction tube at a rate of 57.8 g / h, and 30 NL at a reaction pressure of 7.0 MPa. A catalytic hydrogenation treatment was carried out continuously at 70 ° C. for 10 days while injecting hydrogen gas at a rate of / h to produce a reaction product (a1).

  After passing the reaction product (a1) through the gas-liquid separator, the liquid phase part is intermittently withdrawn to the receiver, and ammonia is dropped and removed from the gas phase part of the receiver to room temperature and normal pressure. Further, an operation for removing remaining ammonia by flowing nitrogen gas was performed, and the reaction product (b1) was intermittently extracted.

  All the extracted reaction product (b1) was mixed and analyzed by gas chromatography. Metaxylylenediamine was 85.3% by weight, 3-cyanobenzylamine was 0.03% by weight, 3-methylbenzylamine was 0.7% by weight, and isophthalonitrile was not detected. The remaining components were metaxylylenediamine oligomers and high boiling point polymers not detected by gas chromatography. In addition, when the amount of residual ammonia was analyzed separately, about 500 ppm remained.

  As described above, when the amount of the solvent containing liquid ammonia is too small during the first catalytic hydrogenation treatment, a large amount of polymer is generated by side reaction, although the amount of cyanobenzylamine is small. The yield of range amine was greatly reduced.

Claims (5)

The following sequential steps:
(1) The first catalytic hydrogenation treatment is performed on phthalonitriles and liquid ammonia or a liquid ammonia and an organic solvent, and the liquid ammonia or a liquid mixture containing the liquid ammonia and the organic solvent is 80% by weight or more. And hydrogenating the phthalonitriles to obtain a reaction product (A),
(2) removing liquid ammonia in the reaction product (A) to obtain a reaction product (B);
(3) subjecting the reaction product (B) to a second catalytic hydrogenation to hydrogenate cyanobenzylamine to obtain a reaction product (C); and (4) distilling the reaction product (C). And then purifying the xylylenediamine, a method for producing xylylenediamine.   The method for producing xylylenediamine according to claim 1, wherein the weight ratio of cyanobenzylamine to xylylenediamine in the reaction product (C) is 0.00005 or less.   The method for producing xylylenediamine according to claim 1, wherein the weight ratio of cyanobenzylamine to xylylenediamine in the reaction product (B) is 0.01 or less.   2. The method for producing xylylenediamine according to claim 1, wherein the content of the liquid ammonia or the liquid ammonia and the organic solvent in the mixed solution is 90% by weight or more.   The method for producing xylylenediamine according to claim 1, wherein the second catalytic hydrogenation treatment is performed in the presence of a catalyst in which nickel and / or cobalt is supported on a support.