JP2996914B2 - Method for producing alkanolamine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an alkanolamine by aminating an alkylene oxide with ammonia in the presence of a heterogeneous catalyst.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an alkanolamine by aminating an alkylene oxide with ammonia, industrially, for example, an ethylene oxide is reacted with ammonia in the presence of water as a catalyst. Methods for producing ethanolamines are known. In this method, besides monoethanolamine,
Diethanolamine and triethanolamine are by-produced. For this reason, monoethanolamine,
It is necessary to control the production ratio of diethanolamine and triethanolamine. Among these ethanolamines, in recent years, in particular, the demand for triethanolamine has been declining, and thus it is required to suppress the production of triethanolamine. For this reason, attempts have been made to efficiently produce monoethanolamine by performing a reaction using a large excess of ammonia with respect to ethylene oxide and circulating and using unreacted ammonia.

However, this method has a selectivity of monoethanolamine of about 60% by weight even when using 10 times the amount of ammonia with respect to ethylene oxide (Ullman Encyclopedia of Industrial Chemistry, 5th edition, A10, volume 4) Page 5), suitable only when a large amount of diethanolamine or triethanolamine is produced together. In addition, since water is used as a catalyst, the cost of recovering the water is high, so that there is a problem that the ethanolamines cannot be obtained at low cost. Further, there is a problem that the obtained alkanolamine aqueous solution has high corrosiveness.

[0004] Therefore, there is a need for a method of reacting an alkylene oxide with ammonia without using water as a catalyst. However, when water does not exist in the reaction system, the alkylene oxide hardly reacts with ammonia. Therefore, the presence of a catalyst is essential for such a reaction.

[0005] As a production method using a catalyst other than water,
For example, Swedish Patent 158167 discloses a method for obtaining an alkanolamine by reacting an alkylene oxide with ammonia using a homogeneous catalyst such as an organic acid, an inorganic acid, and an ammonium salt.

However, when alkanolamine is obtained using a homogeneous catalyst, there is a problem that the alkanolamine to be produced cannot be easily separated from the catalyst. In addition, when the above homogeneous catalyst is used, the yield of monoalkanolamine is only about 60% at the maximum, and it cannot be said that monoalkanolamine can be obtained efficiently. Further, the reactivity of the alkylene oxide with ammonia when the above catalyst is used is not sufficient, and therefore, the catalytic activity in the reaction of compounds such as organic acids, inorganic acids, and ammonium salts is not sufficient. Have.

In order to improve the catalytic activity and the yield of monoalkanolamine, attempts have been made to immobilize a homogeneous acid catalyst. Tokiko 4
Japanese Patent Application Laid-Open No. 9-47728 discloses that, as such a catalyst, an ion exchange resin in which a sulfonic acid group is bonded to a synthetic resin is used, and at the maximum temperature at which a reaction mixture is formed, and the reaction liquid maintains a liquid state. Thus, a method of reacting ammonia with an alkylene oxide while applying a pressure higher than at least the vapor pressure of ammonia is disclosed. The method for producing an alkanolamine using the above catalyst is industrially practiced because the catalyst has relatively good activity and selectivity.

However, the maximum operating temperature (heat-resistant temperature) of a commercially available ion exchange resin is as low as about 120 ° C. (“Ion exchange—Guide to theory and application—”, translated by Rokuro Kuroda and Masami Shibukawa, Published in 1981 by Maruzen Co., Ltd., 34
page). Therefore, for example, when the reaction is performed with a low molar ratio of ammonia to ethylene oxide, the heat of the reaction causes the temperature of the catalyst layer to exceed the heat resistant temperature of the catalyst.
As a result, when used under such temperature conditions for a long time,
There is a problem that the catalyst is deteriorated. For this reason, when using an ion exchange resin as a catalyst, it is necessary to use about 20 mol to 25 mol of ammonia with respect to 1 mol of ethylene oxide in order to prevent deterioration of the ion exchange resin. For this reason, the ion exchange resin has a problem that it can be applied when only monoethanolamine is manufactured, but is difficult to apply when manufacturing diethanolamine or triethanolamine, and lacks flexibility. .

[0009] In order to overcome the drawback of the ion exchange resin, which is inferior in heat resistance, an inorganic catalyst having excellent thermal stability has been studied. As such an inorganic catalyst, silica alumina, which is commonly used, exhibits activity. Therefore, US Pat. No. 4,438,281 discloses that ammonia and ethylene oxide are reacted using this silica alumina as a catalyst. A method is disclosed. "Industrial and Engineering Chemistry, Product Research and Development"
In 1986, Vol. 25, pp. 424-430, a comparative study of ion exchange resins and various zeolite catalysts as catalysts for reacting ammonia with ethylene oxide. Further, JP-A-2-225446 discloses a method of reacting ammonia and ethylene oxide using an acid-activated clay catalyst. In addition, Japanese Unexamined Patent Publication No.
No. 49000 discloses a method for reacting ammonia with an alkylene oxide using a layered crosslinked catalyst.

[0010]

When ethanolamines are produced using silica alumina, a zeolite catalyst, or an acid-activated clay catalyst as a catalyst, depending on the conditions,
In some cases, the yield of monoethanolamine may be 60% by weight or more. However, it is difficult to say that monoalkanolamine can be selectively obtained using any of the catalysts. In addition, regardless of which catalyst is used, in order to improve the selectivity of monoethanolamine, the reaction is carried out by adding 20 to 30 mol or more of ammonia to 1 mol of ethylene oxide. Therefore, the reactor,
It is necessary to increase the size of the apparatus for recovering and circulating the ammonia, which increases the equipment cost, and thus has a problem that the ethanolamines cannot be obtained at low cost.

On the other hand, when reacting ammonia and alkylene oxide using a layered crosslinked catalyst as a catalyst, when the molar ratio of ammonia to alkylene oxide is small, for example, the amount of added ammonia is 5 moles per mole of alkylene oxide. Even in the case of a molar amount, the performance of the monoalkanolamine yield exceeds 60% by weight. The reaction is carried out at the highest temperature at which the reaction mixture is formed and while applying a pressure at least higher than the vapor pressure of ammonia so that the reaction solution maintains a liquid phase.
However, when the concentration of the alkylene oxide is increased, the heat of reaction must be removed in order to maintain the liquid phase, but there is a problem that the heat of reaction cannot be effectively recovered when cooled from the outside. . If the reaction temperature is too high, quality problems such as coloring of the alkanolamine to be produced arise. From this, it is necessary to suppress the temperature rise to some extent.

As described above, when ammonia is reacted with alkylene oxide using a heterogeneous catalyst,
In any case, the reaction is performed while maintaining the ammonia in the liquid phase by maintaining the reaction temperature at or below the boiling point at the reaction pressure. Therefore, in order to suppress the heat of reaction, it is necessary to increase the molar ratio of ammonia to alkylene oxide. However, when the molar ratio of ammonia to alkylene oxide is increased, that is, when the amount of ammonia added to alkylene oxide is increased, equipment costs for a reactor and a device for recovering and recycling ammonia are increased. There is a problem that alkanolamine cannot be obtained at low cost. On the other hand, if the molar ratio between ammonia and alkylene oxide is reduced, the temperature rises due to the heat of reaction, which leads to deterioration of the catalyst and quality problems such as coloring of the resulting alkanolamine. Also,
If the temperature is too high, to maintain the liquid phase,
High pressure must be applied. Further, since the molar ratio between ammonia and alkylene oxide cannot be freely changed, there is a problem that a desired alkanolamine cannot be obtained efficiently.

In the reaction using water as a catalyst, there is known a method of vaporizing ammonia by providing an evaporation surface and a space inside a reactor as disclosed in Japanese Patent Publication No. 52-2887. I have. However, this method
This is a method that can be applied when a homogeneous catalyst called water is used, and cannot be applied to a reaction using a heterogeneous catalyst.

Therefore, it is possible to suppress the rise of the reaction temperature without applying a high reaction pressure and to produce a desired alkanolamine by freely changing the molar ratio of ammonia to alkylene oxide. There is a need for a way to do it.

That is, an object of the present invention is to suppress an increase in reaction temperature without applying a high reaction pressure,
The molar ratio between ammonia and alkylene oxide can be freely changed according to demand, and the reaction heat can be efficiently recovered, and the cost of recovering and circulating ammonia can be reduced. It is an object of the present invention to provide a method for inexpensively producing alkanolamines.

[0016]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned conventional problems, and as a result, conventionally, liquid ammonia and alkylene oxide are reacted in the presence of a heterogeneous catalyst. In such cases, it was considered essential to maintain the reaction temperature below the boiling point at the reaction pressure and maintain the reaction solution in a liquid state, whereas the reaction temperature,
By controlling the reaction pressure, the molar ratio of the raw materials, and the like, the reaction conditions are set such that a part of the liquid ammonia is vaporized by the heat of reaction, and the heat is removed by the latent heat of evaporation of the ammonia,
It has been found that it is possible to suppress the rise in the reaction temperature and efficiently recover the reaction heat,
The present invention has been completed.

That is, the method for producing an alkanolamine according to the present invention comprises the general formula (I)

[0018]

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(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group) and liquid ammonia, By reacting in the presence of a heterogeneous catalyst in the reactor, the general formula (II)

[0020]

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(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and m and n are 0 to (m + n) being 1 to 3) In the method for producing an alkanolamine represented by the formula (3), a part of the liquid ammonia is vaporized.
The reaction pressure at the maximum temperature inside the reactor.
It is characterized in that it is controlled to a vapor pressure of not more than.

Further, in the method for producing an alkanolamine according to the present invention, the addition amount of liquid ammonia to 1 mol of the alkylene oxide is in the range of 1 mol to 50 mol, the reaction temperature is in the range of 20 ° C. to 300 ° C., and , Reaction pressure is 2MPa
It is characterized by being within the range of ~ 30MPa.

Furthermore, the method for producing an alkanolamine according to the present invention is characterized in that the vaporization rate of liquid ammonia in the reactor is in the range of 1% by weight to 80% by weight.

The method for producing an alkanolamine according to the present invention is characterized in that the reaction is carried out adiabatically.

Further, the method for producing an alkanolamine according to the present invention is characterized in that unreacted ammonia is recovered and reused.

According to the above configuration, when reacting ammonia with the alkylene oxide, heat of reaction is taken from the reaction system as heat of vaporization of ammonia. Therefore, even when the alkylene oxide concentration in the raw material is relatively high, the reaction can be performed adiabatically. As described above, according to the present invention, the heat of reaction is used as heat of vaporization of ammonia and is effectively recovered (removed), so that a rise in temperature inside the reactor can be suppressed.

Further, since the heat of reaction is used as the heat of vaporization of ammonia and is efficiently recovered, it is not necessary to increase the molar ratio of ammonia to alkylene oxide in order to suppress the heat of reaction as in the prior art. That is, the molar ratio of ammonia to alkylene oxide can be reduced (that is, the concentration of alkylene oxide in the reaction solution can be increased). Further, since it is not necessary to keep all the ammonia in a liquid phase, the reaction pressure can be reduced. This makes it possible to reduce the size of the reactor (continuous flow reactor) and the apparatus for collecting and circulating ammonia. From this, it is possible to reduce equipment costs for producing alkanolamines and efficiently react ammonia with alkylene oxide. Therefore, the cost for the entire process in the reaction of ammonia and alkylene oxide can be reduced.

Further, since the rise in temperature inside the reactor can be suppressed, the reaction can be carried out with a high alkylene oxide concentration even when a catalyst having poor heat resistance such as an ion exchange resin is used. Therefore, the production method according to the present invention can be applied to a case where only a monoalkanolamine is produced and a case where diethanolamine or triethanolamine is produced. Further, since the reaction can be performed at a temperature equal to or lower than the heat-resistant temperature of the ion exchange resin, deterioration of the ion exchange resin can be suppressed. For this reason, the life of the catalyst can be extended.

Further, according to the present invention, as described above,
Since the rise in reaction temperature can be suppressed and the reaction pressure can be reduced, the molar ratio of ammonia to alkylene oxide can be freely changed according to demand. As described above, by freely changing the molar ratio between ammonia and alkylene oxide according to demand, the number of addition of alkylene oxide molecules to one molecule of ammonia is 1,
Since the formation ratio of a few kinds of products (monoalkanolamine, dialkanolamine, trialkanolamine) can be freely controlled, desired alkanolamines can be produced with high productivity.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail. In the method for producing an alkanolamine represented by the general formula (II) (hereinafter referred to as alkanolamines), the alkylene oxide represented by the general formula (I) used as a raw material is represented by the formula:
^A compound in which the substituents represented by ¹ , R ² , R ³ and R ⁴ are each independently composed of a hydrogen atom, a methyl group, or an ethyl group. Such compounds are not particularly limited, but specific examples include ethylene oxide and propylene oxide. One of these alkylene oxides may be used alone, or two or more of them may be appropriately mixed and used. Among these alkylene oxides, ethylene oxide is preferred because ethanolamines that are particularly useful industrially can be obtained.

The heterogeneous catalyst is not particularly limited, and may be, for example, a solid acid such as a cation exchange resin, acid-activated clay, silica alumina, molecular sieves (trade name; synthetic zeolite), zeolite, or the like. Various known heterogeneous catalysts such as a catalyst; a rare earth element-supported catalyst; and a crosslinked layered compound catalyst can be used. Furthermore, according to the present invention, since the temperature rise inside the reactor (continuous flow reactor) can be suppressed, conventionally, when the molar ratio of ammonia to alkylene oxide is low due to poor heat resistance (in the reaction solution, Ion exchange resins that could not be used (when the alkylene oxide concentration is high) can also be used as the heterogeneous catalyst according to the present invention. Among these heterogeneous catalysts, inorganic catalysts are preferable because of their excellent heat resistance, and catalysts in which a rare earth element is supported on a heat-resistant carrier are particularly preferable.

In the alkanolamines represented by the general formula (II) according to the present invention, the substituents represented by R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, A compound composed of a methyl group or an ethyl group and having 1 to 3 alkanol groups represented by m or n,
That is, monoalkanolamine and / or dialkanolamine and / or trialkanolamine. That is, by reacting the alkylene oxide represented by the general formula (I) with liquid ammonia in the presence of the heterogeneous catalyst, alkanolamines corresponding to the alkylene oxide can be obtained. Such alkanolamines are not particularly limited, but specific examples include monoethanolamine, diethanolamine, triethanolamine, and propanolamine. As the alkanolamines represented by the general formula (II), an alkanol group represented by m and an alkanol group represented by n can be appropriately selected depending on an alkylene oxide and a catalyst to be used.

The reactor used in the present invention is not particularly limited as long as it is a continuous flow reactor.
Various conventionally known reactors can be used. Also,
The method of supplying the raw materials to the reactor and the method of charging the catalyst are not particularly limited, but a method of preheating the raw materials before performing the reaction is preferable.

In the present invention, the recovery (removal of heat) of the reaction heat generated by the reaction between ammonia and the alkylene oxide is carried out by vaporizing a part of the liquid ammonia. That is, in the present invention, the reaction between the ammonia and the alkylene oxide is based on the maximum temperature in the reactor expected from the temperature rise due to the heat of reaction (approximately 24 Kcal / mol).
By controlling the reaction pressure below the vapor pressure of the reaction liquid at the maximum temperature, the reaction is performed in a gas-liquid mixed phase state.

The amount of liquid ammonia added to the alkylene oxide is not particularly limited, but is preferably in the range of 1 mol to 50 mol of ammonia, more preferably in the range of 2 mol to 40 mol, per 1 mol of the alkylene oxide. Is more preferred. If the molar ratio between the alkylene oxide and ammonia is too small (that is, the concentration of the alkylene oxide in the reaction solution is high), the generated reaction heat is too large to sufficiently remove the heat, which is not preferable. On the other hand, if the molar ratio between the alkylene oxide and ammonia is too large (that is, the concentration of the alkylene oxide in the reaction solution is low), the amount of recovered ammonia is too large.
For this reason, it is necessary to increase the size of the reactor and the apparatus for recovering and circulating the ammonia, which increases the equipment cost. As a result, the alkanolamines cannot be obtained at low cost, which is not preferable.

The reaction temperature is not particularly limited, but is preferably in the range of 20 ° C. to 300 ° C., more preferably in the range of 30 ° C. to 250 ° C., and most preferably in the range of 30 ° C. to 200 ° C. . If the reaction temperature is lower than 20 ° C., the reaction rate will be low and the amount of catalyst required to completely convert the alkylene oxide to the desired alkanolamine will be too high. For this reason, it is necessary to enlarge the reactor,
Since the equipment cost increases, the alkanolamines cannot be obtained at low cost, which is not preferable. On the other hand, if the reaction temperature is higher than 300 ° C., the temperature inside the reactor rises too much, and the amount of ammonia vaporized becomes too large, so that the liquid phase portion of the reaction solution decreases and the reaction between ammonia and the alkylene oxide proceeds smoothly. It is not preferable because it does not progress.

The reaction pressure is preferably in the range of 2 to 30 MPa, more preferably in the range of 4 to 20 MPa, and more preferably 5 MPa.
Most preferably, it is in the range of 15 MPa. If the reaction pressure is lower than 2 MPa, the amount of ammonia vaporized is too large, the liquid phase portion is reduced, and the reaction between ammonia and the alkylene oxide does not proceed smoothly. on the other hand,
If the reaction pressure is higher than 30 MPa, the temperature inside the reactor does not rise to the boiling point of the reaction solution, and ammonia is not vaporized.

The remaining conditions are determined by determining two of the three conditions of the amount of ammonia added to the alkylene oxide, the reaction temperature, and the reaction pressure, but by satisfying all three conditions, , The reaction heat can be efficiently recovered (removed),
The reaction between the alkylene oxide and ammonia can be performed more efficiently.

As described above, in the present invention, since heat is removed by vaporizing ammonia, it is not necessary to provide a cooling device in the reactor, or even if it is provided, the heat transfer area can be reduced. This makes it possible to simplify the configuration of the apparatus relating to the reaction.

In the case where dialkanolamine or trialkanolamine is produced by increasing the concentration of alkylene oxide, the reaction temperature may be too high simply by removing heat by vaporizing ammonia. Therefore, in such a case, an external heat removal method by cooling from a normal reactor wall and a heat removal method by vaporization of ammonia can be used in combination.

The method for recovering ammonia is not particularly limited, and various conventionally known methods can be used. In the present invention, ammonia is vaporized using the heat of reaction, so that the heat of reaction can be used efficiently. From this, it is possible to reduce the cost for recovering the unreacted ammonia.

Further, in order to maintain a stable operation state of the reactor and recover the reaction heat, the vaporization rate of ammonia in the reactor is preferably kept within a range of 1% by weight to 80% by weight. , More preferably in the range of 10% to 50% by weight. If the vaporization rate of the ammonia is less than 1% by weight, the latent heat of vaporization of the ammonia becomes too small and the heat of reaction cannot be sufficiently removed. For this reason, the reaction temperature is too high, which is not preferable. On the other hand, if the vaporization rate of ammonia is more than 80% by weight, the liquid phase portion decreases, and the reaction between ammonia and alkylene oxide does not proceed smoothly, which is not preferable. In the present invention, the vaporization rate of ammonia is:
The values calculated based on the latent heat of vaporization of ammonia and the difference between the inlet and outlet temperatures of the reactor are shown.

Under the above-mentioned conditions, the LHSV (liquid hourly space velocity) depends on the type and amount of the catalyst, but is in the range of 1 hr ^-1 to 1 hr ^-1.
Is preferably in the range of 00hr ^-1, more preferably in the range of 2hr ^-1 ~50hr ^-1. If the LHSV is less than ¹ hr ^-1 , the contact time between ammonia and the alkylene oxide with the catalyst is sufficiently long, so that the alkylene oxide can be efficiently converted into the desired alkanolamines, but the alkylene oxide is completely converted. The amount of catalyst required to convert to the desired alkanolamines is relatively too high. Further, the amount of alkanolamines produced per unit time is reduced. For this reason, it is necessary to increase the size of the reactor, which leads to an increase in equipment cost, and it is not preferable because the alkanolamines cannot be obtained at low cost. On the other hand, if the LHSV is greater than 100 hr ^-1 , the contact time between ammonia and the alkylene oxide with the catalyst is too short, so that the alkylene oxide cannot be sufficiently converted into the desired alkanolamine, which is not preferable.

As described above, according to the production method of the present invention, when reacting ammonia with alkylene oxide, the heat of reaction is taken from the reaction system as heat of vaporization of ammonia. Therefore, even when the alkylene oxide concentration in the raw material is relatively high, the reaction can be performed adiabatically. As described above, according to the present invention, the heat of reaction is used as heat of vaporization of ammonia and is effectively recovered (removed), so that a rise in temperature inside the reactor can be suppressed.

Further, since the heat of reaction is used as the heat of vaporization of ammonia and is efficiently recovered, it is not necessary to increase the molar ratio between ammonia and alkylene oxide in order to suppress the heat of reaction as in the prior art. That is, the molar ratio of ammonia to alkylene oxide can be reduced (that is, the concentration of alkylene oxide in the reaction solution can be increased). Further, since it is not necessary to keep all the ammonia in a liquid phase, the reaction pressure can be reduced. This makes it possible to reduce the size of the reactor (continuous flow reactor) and the apparatus for collecting and circulating ammonia. From this, it is possible to reduce equipment costs for producing alkanolamines and efficiently react ammonia with alkylene oxide. Therefore, the cost for the entire process in the reaction of ammonia and alkylene oxide can be reduced.

Further, since the rise in temperature inside the reactor can be suppressed, the reaction can be carried out with a high alkylene oxide concentration even when a catalyst having poor heat resistance such as an ion exchange resin is used. Therefore, the production method according to the present invention can be applied to a case where only a monoalkanolamine is produced and a case where diethanolamine or triethanolamine is produced. Further, since the reaction can be performed at a temperature equal to or lower than the heat-resistant temperature of the ion exchange resin, deterioration of the ion exchange resin can be suppressed. For this reason, the life of the catalyst can be prolonged.

Further, according to the present invention, as described above,
Since the rise in reaction temperature can be suppressed and the reaction pressure can be reduced, the molar ratio of ammonia to alkylene oxide can be freely changed according to demand. As described above, by freely changing the molar ratio between ammonia and alkylene oxide according to demand, the number of addition of alkylene oxide molecules to one molecule of ammonia is 1,
Since the formation ratio of a few kinds of products (monoalkanolamine, dialkanolamine, trialkanolamine) can be freely controlled, desired alkanolamines can be produced with high productivity.

[0048]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto.

The LHSV, the selectivity of ethanolamines as alkanolamines, and the vaporization rate of ammonia are defined as follows.

[0050]

(Equation 1)

The conversion of ethylene oxide was almost 100.
%, And products other than ethanolamines were hardly formed. The amount of ammonia vaporized inside the reactor was calculated based on the latent heat of vaporization of ammonia and the difference between the inlet temperature and the outlet temperature of the reactor.

Example 1 200 g of montmorillonite was added to 10 L of a 0.05 mol / L lanthanum nitrate aqueous solution while stirring. The mixture was stirred at room temperature for one day, after which
Filtered. Then, the solid obtained by filtration, 10
The resultant was washed with L pure water and then dried at 100 ° C. for 1 day.
Further, this solid was subjected to a high-temperature treatment at 500 ° C. for 5 hours under a flow of air by a predetermined method. The obtained solid is
It was pulverized to a particle size of 0.1 mm to 0.2 mm by a predetermined method to obtain a catalyst (hereinafter, referred to as catalyst A for convenience of description).

Next, a reactor having an inner volume of 60 cm ³ (made of stainless steel tube: inner diameter 10.7 mm) was charged with the catalyst A. On the other hand, in front of the reactor (upstream side), a tubular preheating section (inner diameter 6 mm,
20cm in length), using an oil bath as a preheater,
The preheating section was heated. Next, liquid ammonia and ethylene oxide were continuously fed into the preheating section at a constant rate by a so-called ascending method using a high-pressure pump, whereby the ammonia and ethylene oxide were mixed and heated, and supplied to the reactor. At this time, the molar ratio of ammonia to ethylene oxide was set to 10. The reactor was slightly heated by a heater (heater) for keeping the temperature warm, and supplied with the amount of heat lost by heat radiation, so that the reactor was substantially insulated. At this time, the reactor inlet temperature was set to 70 ° C., and the reaction pressure was controlled to 10 MPa. Then, ethylene oxide and ammonia were continuously reacted. The LHSV at this time was 5 hr ^-1 . The outlet temperature of the reactor was 150 ° C. Next, the obtained reaction solution was collected, and the reaction solution was analyzed using gas chromatography to determine the selectivity of the product, ethanolamines. As a result, the selectivity for monoethanolamine was 77.5% by weight, the selectivity for diethanolamine was 20.0% by weight, and the selectivity for triethanolamine was 2.5% by weight. Table 1 shows the reaction conditions and the reaction results.

Example 2 The same reaction and operation as in Example 1 were performed, except that the reaction pressure was changed from 10 MPa to 9 MPa. Table 1 shows the reaction conditions and reaction results.
Shown in

Comparative Example 1 The same reaction and operation as in Example 1 were performed, except that the reaction pressure was changed from 10 MPa to 20 MPa so as to prevent ammonia from evaporating. Table 1 shows the reaction conditions and the reaction results.

Example 3 The same procedure as in Example 1 was carried out except that the molar ratio of ammonia to ethylene oxide was changed from 10 to 20 and the reactor inlet temperature was changed from 70 ° C. to 100 ° C. Reaction and operation were performed. Table 1 shows the reaction conditions and the reaction results.

Comparative Example 2 The same reaction and operation as in Example 3 were performed, except that the reaction pressure was changed from 10 MPa to 16 MPa in order to prevent ammonia from evaporating. Table 1 shows the reaction conditions and the reaction results.

Example 4 The procedure of Example 1 was repeated, except that the molar ratio of ammonia to ethylene oxide was changed from 10 to 8, and the reactor inlet temperature was changed from 70 ° C. to 50 ° C. Reaction and operation were performed. Table 1 shows the reaction conditions and the reaction results.

Comparative Example 3 The same reaction and operation as in Example 4 were performed, except that the reaction pressure was changed from 10 MPa to 25 MPa so as to prevent ammonia from evaporating. Table 1 shows the reaction conditions and the reaction results.

Example 5 In Example 1, the catalyst was changed from catalyst A to a cation exchange resin (DOW Chemical Co., Ltd .: DOW).
EX (registered trademark), 50W-X8, 20-50 mesh; hereinafter, referred to as catalyst B for convenience of explanation), and
Molar ratio of ammonia to ethylene oxide from 10
20 and the reactor inlet temperature from 70 ° C to 90 ° C
The same reaction and operation as in Example 1 were carried out, except that the reaction was changed to. Table 1 shows the reaction conditions and the reaction results.

Comparative Example 4 In Example 5, the reaction pressure was increased from 10 MPa to 20 MPa so that ammonia did not evaporate.
The same reaction and operation as in Example 5 were performed, except that the reaction was changed to. Table 1 shows the reaction conditions and the reaction results.

[0062]

[Table 1]

Example 6 A jacketed reactor (stainless steel) having an inner diameter of 20 mm and a length of 1700 mm was charged with the catalyst B so that the catalyst layer length was 1500 mm. At this time, a portion 200 mm to 600 mm from the inlet of the catalyst layer was filled with the catalyst B diluted with inert quartz sand so as to have a volume of 1: 1. A thermometer protective tube having an outer diameter of 3 mm was attached to the center of the reactor for temperature measurement, and the reactor was kept at 100 ° C. by flowing a heat medium through a jacket for keeping the temperature.
Next, the ammonia and ethylene oxide are mixed and heated by using a high-pressure pump to feed liquid ammonia and ethylene oxide at a constant rate by a so-called ascending method so that the total amount per hour becomes 4 kg. Supplied. At this time, the molar ratio of ammonia to ethylene oxide was set to 10, the inlet temperature of the reactor was set to 60 ° C., and the reaction pressure was controlled to 8 MPa. Then, ethylene oxide and ammonia were continuously reacted. LHSV at this time
Was 17 hr ⁻¹ . Also, since the outer wall of the reactor is kept at 100 ° C., the heat of reaction is removed through the reactor wall,
The maximum temperature in the reactor was 120 ° C. FIG. 1 shows the temperature distribution inside the catalyst layer at this time. Next, the obtained reaction solution was collected, and the reaction solution was analyzed using the same method as in Example 1 to determine the selectivity of ethanolamine as a product. Table 2 shows the reaction conditions and the reaction results.

Comparative Example 5 The same reaction and operation as in Example 6 were performed, except that the reaction pressure was changed from 8 MPa to 30 MPa so that ammonia did not evaporate. FIG. 2 shows the temperature distribution inside the catalyst layer at this time. Table 2 shows the reaction conditions and the reaction results.

Example 7 In a reactor similar to that in Example 6,
The catalyst A was filled so that the catalyst layer length was 1500 mm. At this time, the portion of 200 mm to 800 mm from the inlet of the catalyst layer was filled with the catalyst A diluted with inert quartz sand so as to have a volume of 1: 1. At the center of the reactor, a thermometer protection tube with an outer diameter of 3 mm was attached for temperature measurement.
A heat medium was flowed through the jacket to keep the temperature at 120 ° C. Next, the ammonia and ethylene oxide are mixed and heated by using a high-pressure pump to feed liquid ammonia and ethylene oxide at a constant rate by a so-called ascending method so that the total amount per hour becomes 4 kg. Supplied. At this time, the molar ratio of ammonia to ethylene oxide was set to 5, the inlet temperature of the reactor was set to 50 ° C,
The reaction pressure was controlled at 10 MPa. Then, ethylene oxide and ammonia were continuously reacted. LH at this time
The SV was 16 hr ^-1 . The outer wall of the reactor is 120 ° C.
, The heat of reaction was removed through the reactor walls and the maximum temperature in the reactor was 146 ° C. FIG. 3 shows the temperature distribution inside the catalyst layer at this time. Next, the obtained reaction solution was collected, and the reaction solution was analyzed using the same method as in Example 1 to determine the selectivity of ethanolamine as a product. Table 2 shows the reaction conditions and the reaction results.

Comparative Example 6 The same reaction and operation as in Example 7 were performed, except that the reaction pressure was changed from 10 MPa to 40 MPa so as to prevent ammonia from evaporating. FIG. 4 shows the temperature distribution inside the catalyst layer at this time. Table 2 shows the reaction conditions and the reaction results.

Example 8 10 kg of montmorillonite was added to 500 L of a 0.05 mol / L yttrium nitrate aqueous solution while stirring. The mixture was stirred at room temperature for 1 day and then filtered. Next, the solid obtained by filtration is washed with 500 L of pure water, and 5 kg of crystalline cellulose powder is obtained.
And kneading with a kneader, then extruder
It was molded to 0.4 mm and 1 mm to 3 mm in length. Further, this solid is dried at 100 ° C. for one day, and then subjected to a high temperature treatment at 500 ° C. for 5 hours under a flow of air by a predetermined method to obtain a catalyst (hereinafter referred to as catalyst C for convenience of explanation). did.

Next, using the catalyst C, a reaction was carried out using a reaction apparatus shown in FIG. First, a reactor 1 (made of steel: inner diameter 60 mm) having an inner volume of 7 L was filled with 6 L of catalyst C. On the other hand, in front of the reactor (upstream side), a tubular preheater 2 (20 mm in inner diameter, 1 m in length, and 5 mm in diameter of the preheating section) provided with an electric heater (not shown) is provided outside, and the preheating section is heated by an electric heater did. Next, liquid ammonia and ethylene oxide were continuously fed into the preheater 2 at a constant rate by a so-called ascending method using the high-pressure pumps 3 and 5. Thereby, the ammonia in the ammonia material cylinder 10 and the ethylene oxide in the ethylene oxide material tank 11 are mixed and mixed.
Heated and fed to reactor 1. At this time, the molar ratio of ammonia to ethylene oxide was set to 8. Reactor 1
Is heated slightly by an unillustrated heater (electric heater) to keep the heat, and by supplying the amount of heat lost by heat dissipation,
Substantially insulated. At this time, the inlet temperature of the reactor 1 was set at 45 ° C., and the reaction pressure was controlled at 10 MPa. Then, ethylene oxide and ammonia were continuously reacted.
The LHSV at this time was 3.5 hr ^-1 . The outlet temperature of the reactor 1 was 155 ° C. The reaction liquid exiting the reactor 1 was reduced in pressure to 2 MPa under the control of the pressure control valve 6 and introduced into the ammonia recovery tower 7. Here, unreacted ammonia is separated from ethanolamines generated by the reaction, condensed in an ammonia condenser 9, collected in a collected ammonia tank 8, and recycled by the high-pressure pump 4 to the reactor 1. used. On the other hand, ethanolamines as products were collected. This recycle reaction was continued for 400 hours, and after confirming that the reaction activity was stabilized, the selectivity of the product ethanolamines was determined in the same manner as in Example 1. As a result, the selectivity for monoethanolamine was 73.0% by weight, the selectivity for diethanolamine was 23.5% by weight, and the selectivity for triethanolamine was 3.5% by weight. In addition, no accumulation of by-products due to the recycling use of ammonia and no change in the selectivity of ethanolamines due to the catalyst A were found, and stable production was possible.

[0069]

[Table 2]

As is clear from the results of the above Examples and Comparative Examples, the outlet temperatures of the reactors of Examples 1 to 5,
It can be seen that the maximum catalyst layer temperature in Examples 6 and 7 was kept lower than the corresponding outlet temperature of the reactor or the maximum catalyst layer temperature in the corresponding comparative example, regardless of the conditions. Further, in Comparative Examples 1, 3, 5, and 6, when the reaction was carried out at a low molar ratio of ammonia to alkylene oxide, the reaction heat caused the outlet temperature of the reactor or the maximum temperature of the catalyst layer to be extremely high. In contrast, Examples 1.2
-In the case of 4.6 to 8, it can be seen that the reaction temperature can be suppressed from increasing even when the reaction is performed with a lower molar ratio of ammonia to alkylene oxide. From this, if the production method of the present invention is used, it is possible to freely change the molar ratio between ammonia and alkylene oxide according to demand.

Further, the outlet temperatures of the reactors of Comparative Examples 1 to 4 and the catalyst layer maximum temperature of Comparative Example 6 were compared with the corresponding reactor outlet temperatures or catalyst layer maximum temperatures.
Since it is considerably high, it can be seen that the ethanolamines obtained in Comparative Examples 1 to 6 are inferior in quality as compared with the ethanolamines obtained in Examples 1 to 7, respectively.

The outlet temperature of the reactor in Comparative Example 4 and the maximum temperature of the catalyst layer in Comparative Example 5 greatly exceeded the normal heat-resistant temperature of the catalyst B of 120 ° C.
There is a problem in terms of catalyst life. Heretofore, ion exchange resins such as catalyst B have been widely used industrially because of their excellent selectivity and catalytic activity, but when they are reacted at a molar ratio of ammonia to alkylene oxide of 20 or less. As can be seen from Comparative Examples 4 and 5, there was a problem that the heat of reaction greatly exceeded the heat-resistant temperature of the catalyst, and as a result, the catalyst was significantly deteriorated.
However, according to the method of the present embodiment, the reaction can be performed at a temperature equal to or lower than the heat resistant temperature of the catalyst, so that the life of the catalyst can be extended.

From the above, according to the method of the present invention,
By effectively collecting the heat of reaction, an increase in the reaction temperature can be suppressed. Furthermore, it is not necessary to apply a high reaction pressure to suppress the vaporization of ammonia. For this reason, it is possible to reduce the cost of an apparatus for recovering and circulating ammonia and economically produce alkanolamine. Further, since the molar ratio of ammonia to alkylene oxide can be freely changed according to demand, a desired alkanolamine can be obtained with high productivity.

[0074]

According to the present invention, as described above, the compound represented by the general formula (I)

[0075]

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Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and liquid ammonia, By reacting in the presence of a heterogeneous catalyst in the reactor, the general formula (II)

[0077]

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(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and m and n are 0 to 3 in which (m + n) is 1 to 3) In the method for producing an alkanolamine represented by the formula (3), a part of the liquid ammonia is vaporized.
The reaction pressure at the maximum temperature inside the reactor.
This is a method of controlling the vapor pressure to be equal to or lower than the vapor pressure of

Further, as described above, the method for producing an alkanolamine according to the present invention is characterized in that the addition amount of liquid ammonia to 1 mol of the above-mentioned alkylene oxide is in the range of 1 mol to 50 mol, and the reaction temperature is 20 to 300 ° C. This is a method in which the reaction pressure is within the range and 2 MPa to 30 MPa.

Further, the method for producing an alkanolamine of the present invention is a method in which the vaporization rate of liquid ammonia in the reactor is in the range of 1% by weight to 80% by weight as described above.

The method for producing an alkanolamine of the present invention is a method in which the reaction is conducted adiabatically as described above.

Further, the method for producing an alkanolamine according to the present invention is a method for recovering and reusing unreacted ammonia as described above.

According to the production method of the present invention, when reacting ammonia with alkylene oxide, the heat of reaction is taken from the reaction system as heat of vaporization of ammonia. Therefore, even when the alkylene oxide concentration in the raw material is relatively high, the reaction can be performed adiabatically. As described above, according to the present invention, the heat of reaction is used as heat of vaporization of ammonia and is effectively recovered (removed), so that a rise in temperature inside the reactor can be suppressed.

Further, since the heat of reaction is used as heat of vaporization of ammonia and is efficiently recovered, it is not necessary to increase the molar ratio of ammonia to alkylene oxide in order to suppress the heat of reaction as in the conventional case. That is, the molar ratio of ammonia to alkylene oxide can be reduced (that is, the concentration of alkylene oxide in the reaction solution can be increased). Further, since it is not necessary to keep all the ammonia in a liquid phase, the reaction pressure can be reduced. This makes it possible to reduce the size of the reactor (continuous flow reactor) and the apparatus for collecting and circulating ammonia. From this, it is possible to reduce equipment costs for producing alkanolamines and efficiently react ammonia with alkylene oxide. Therefore, the cost for the entire process in the reaction of ammonia and alkylene oxide can be reduced.

Further, since the temperature rise inside the reactor can be suppressed, the reaction can be carried out with a high alkylene oxide concentration even when a catalyst having poor heat resistance such as an ion exchange resin is used. Therefore, the production method according to the present invention can be applied to a case where only a monoalkanolamine is produced and a case where diethanolamine or triethanolamine is produced. Further, since the reaction can be performed at a temperature equal to or lower than the heat-resistant temperature of the ion exchange resin, deterioration of the ion exchange resin can be suppressed. For this reason, the life of the catalyst can be extended.

Further, according to the present invention, as described above,
Since the rise in reaction temperature can be suppressed and the reaction pressure can be reduced, the molar ratio of ammonia to alkylene oxide can be freely changed according to demand. As described above, by freely changing the molar ratio between ammonia and alkylene oxide according to demand, the number of addition of alkylene oxide molecules to one molecule of ammonia is 1,
Since the formation ratio of a few types of products (monoalkanolamine, dialkanolamine, trialkanolamine) can be freely controlled, desired alkanolamines can be produced with high productivity. It also has an effect.

[Brief description of the drawings]

FIG. 1 is a graph showing a temperature distribution inside a catalyst layer of a reactor in Example 6.

FIG. 2 is a graph showing a temperature distribution inside a catalyst layer of a reactor in Comparative Example 5.

FIG. 3 is a graph showing a temperature distribution inside a catalyst layer of a reactor in Example 7.

FIG. 4 is a graph showing a temperature distribution inside a catalyst layer of a reactor in Comparative Example 6.

FIG. 5 is a block diagram schematically showing one example of a reaction apparatus for performing the production method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor 2 Preheater 3 High pressure pump 4 High pressure pump 5 High pressure pump 6 Pressure control valve 7 Ammonia recovery tower 8 Recovered ammonia tank 9 Ammonia condenser 10 Ammonia material cylinder 11 Ethylene oxide material tank

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C07C 215/06 C07C 213/04

Claims (5)

(57) [Claims] 1. A compound of the general formula (I) (Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group) and liquid ammonia in a continuous flow reactor. The reaction is carried out in the presence of a heterogeneous catalyst to give a compound of the general formula (II) (Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and m and n are integers of 0 to 3 in which (m + n) becomes 1 to 3) Represents)
In the method for producing an alkanolamine represented by the formula , the reaction pressure is increased so that a part of the liquid ammonia evaporates.
Below the vapor pressure of the reaction solution at the maximum temperature inside the reactor
A method for producing an alkanolamine, which comprises controlling . 2. The addition amount of liquid ammonia to 1 mol of said alkylene oxide is in the range of 1 mol to 50 mol, the reaction temperature is in the range of 20 ° C. to 300 ° C. and the reaction pressure is 2 MPa to 2 mol.
The method for producing an alkanolamine according to claim 1, wherein the pressure is within a range of 30 MPa. 3. The method for producing an alkanolamine according to claim 1, wherein the vaporization rate of the liquid ammonia in the reactor is in the range of 1% by weight to 80% by weight. 4. The process for producing an alkanolamine according to claim 1, wherein the reaction is carried out adiabatically. 5. The process for producing an alkanolamine according to claim 1, wherein unreacted ammonia is recovered and reused.