JPH1190238A - Preparation of catalyst for manufacture alkanolamine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of impurities to be produced by treating with an acid a catalyst which is uneven to a reaction system and is used for the manufacture of alkanolamine represented by specific formula by causing a chemical reaction between alkylene oxide represented by specific formula and ammonia. SOLUTION: In formulae I, II (wherein, R1, R2, R3 and R4 and a hydrogen atom, a methyl group or an ethyl group; m and n are an integer of 0-3 which makes (n+m) 1-3), the catalyst which is ununiform to a reaction system and is used for the manufacture of alkanolamine represented by formula II by causing a chemical reaction between alkylene oxide represented by formula I and ammonia, is treated with an acid. The preferred catalyst is a catalyst of such a construction that a rare earth element is carried by a fire-resistant inorganic carrier. The acid to be used is particularly not limited but is especially preferably hydrochloric acid and/or nitric acid. The treatment method using the acid is not particularly limited but is especially preferably to thermally treat the catalyst in the presence of the acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for preparing a catalyst used for producing an alkanolamine by reacting an alkylene oxide with ammonia, a catalyst for producing an alkanolamine prepared by the method, and a method for producing the alkanolamine. The present invention relates to a method for producing an alkanolamine used.

[0002]

2. Description of the Related Art As a method for producing an alkanolamine by aminating an alkylene oxide with ammonia, conventionally, industrially, an ethyleneamine, that is, a monoethanolamine, is produced by reacting ethylene oxide with aqueous ammonia using water as a catalyst. , Diethanolamine and triethanolamine are being produced.

[0003] It is generally known that the impurities generated during the production of ethanolamines are glycol ethers, which are compounds in which the hydroxyl groups of ethanolamines are ethoxylated.

[0004] Specifically, impurities produced during the production of ethanolamines include monoethanolamine glycol ether H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ OH and diethanolamine glycol ether (HOCH ₂ C).
H ₂ ) HN (CH ₂ CH ₂ OCH ₂ CH ₂ OH), triethanolamine glycol ether (HOCH ₂ CH ₂ ) ₂ N
(CH ₂ CH ₂ OCH ₂ CH ₂ OH).

[0005] These impurities include monoethanolamine,
It is not desirable for commercial use of diethanolamine and triethanolamine. In particular, diethanolamine glycol ether and diethanolamine, and triethanolamine glycol ether and triethanolamine have boiling points close to each other and are very difficult to separate, so that diethanolamine glycol ether or triethanol as an impurity in the product diethanolamine or triethanolamine as impurities. Amine glycol ether will be mixed.

[0006] In addition, impurities generated during the production of ethanolamines reduce the yield of monoethanolamine, diethanolamine and triethanolamine.

As a method for reducing such impurities generated by the conventional method, US Pat. No. 5,334,763 discloses a method of adding a very small amount of carbon dioxide or a compound generating carbon dioxide to a reactor. Have been.

On the other hand, in the conventional method, since water is used as a catalyst, there are problems such as a large utility cost for the recovery of the water and a high corrosiveness of the alkanolamine aqueous solution. Many attempts have also been made on a method for producing alkanolamines in the above. However, since the alkylene oxide and ammonia hardly react, the presence of a catalyst is indispensable.

Therefore, for example, homogeneous catalysts such as organic acids, inorganic acids and ammonium salts have been proposed (Swedish Patent No. 158,167). However, this homogeneous catalyst has difficulty in separating the catalyst, and its performance is not sufficient. As an attempt to fix the homogeneous acid catalyst, an ion exchange resin having a sulfonic acid group fixed to the resin has been proposed (Japanese Patent Publication No. 49-47728). This catalyst has relatively high activity and selectivity and is industrially practiced.

However, ion exchange resins have a problem that the maximum use temperature is low. The maximum temperature at which commercially available ion-exchange resins can be used is as low as about 120 ° C. (“Ion-exchange-a guide to theory and application-”, translated by Rokuro Kuroda and Masami Shibukawa, published by Maruzen Co., Ltd. in 1981, page 34) Therefore, when the reaction is carried out with a lower molar ratio of ammonia and ethylene oxide, the temperature of the catalyst layer exceeds the heat resistance temperature due to the heat of the reaction, and the catalyst deteriorates when used under such temperature conditions for a long time. There is a problem.
Therefore, the molar ratio of ammonia to ethylene oxide is 2
It is difficult to reduce the amount to about 0 to 25 or less, and even if it can be applied when only monoethanolamine is manufactured, it is difficult to apply when manufacturing diethanolamine or triethanolamine, and there is a problem of increasing flexibility. .

[0011] In order to overcome the drawback of the ion exchange resin having low heat resistance, an inorganic catalyst having excellent heat stability has been studied. U.S. Pat. No. 4,438,281 states that
It is disclosed that commonly used silica alumina exhibits activity. Industrial and Engineering Chemistry, Product Research and Development, 1986, Volume 25, 424-
On page 430, ion exchange resins and various zeolite catalysts are compared and studied. In addition, Japanese Patent Application Laid-Open No. 2-225446
In the publication, an acid-activated clay catalyst is disclosed. Further, JP-A-7-173114 discloses a catalyst in which a rare earth element is supported on an inorganic refractory carrier.

[0012] However, none of these known documents mention impurities generated during the production of ethanolamines, that is, monoethanolamine glycol ether, diethanolamine glycol ether, and triethanolamine glycol ether.

The above-mentioned US Pat. No. 5,334,763 does not disclose a method for reducing impurities when an inorganic catalyst is used.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art. That is, one object of the present invention is to provide a method for preparing a heterogeneous catalyst which is a heterogeneous catalyst to be used in producing alkanolamines and which is effective in reducing the amount of impurities formed. Is to do. Another object of the present invention is to provide the catalyst thus prepared itself and a process for producing alkanolamines using the catalyst.

[0015]

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, the heterogeneous catalyst for producing alkanolamine has been treated with an acid in advance to obtain glycol ethers and the like. It has been found that the amount of undesirable impurities produced during the production of alkanolamines can be reduced.

Thus, according to the present invention, general formula (I)

[0017]

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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 react with ammonia Formula (II)

[0019]

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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 (n + m) is 1 to 3) A catalyst for producing an alkanolamine represented by the formula (1), wherein the catalyst which is heterogeneous in the reaction system is treated with an acid: Is provided.

According to the present invention, there is also provided an alkanolamine-producing catalyst prepared by the above method.

According to the present invention, the alkanolamine represented by the general formula (II) is produced by reacting the alkylene oxide represented by the general formula (I) with ammonia in the presence of such a catalyst. A method for producing an alkanolamine is provided.

The heterogeneous catalysts for producing alkanolamines include solid acid catalysts such as acid-activated clay, silica alumina, molecular sieves, and zeolite; catalysts having a rare earth element supported on an inorganic refractory carrier; and crosslinked layered compound catalysts. Conventionally known heterogeneous catalysts can be used. Among them,
A catalyst in which a rare earth element is supported on an inorganic refractory carrier is preferred, and a catalyst in which the inorganic refractory carrier is a layered clay compound is particularly preferred.

The acid used in the treatment is not particularly limited as long as it does not remain in the catalyst due to washing, thermal decomposition, etc., and is a volatile acid such as hydrochloric acid if it is an inorganic acid. Oxalic acid, glycolic acid and the like can be used as long as they are nitric acid or organic. Among these acids, hydrochloric acid and / or nitric acid are particularly preferred.

Further, the treatment method using the acid is not particularly limited, and for example, the catalyst can be stirred in an acid or the catalyst can be heat-treated in the presence of an acid.
Among these treatments, it is particularly preferable to heat-treat the catalyst in the presence of an acid.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail.

In the method for producing the alkanolamine represented by the general formula (II) (hereinafter referred to as alkanolamines), the general formula (I) used as a raw material
Wherein R ¹ , R ² , R
^A compound in which the substituents represented by 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 which are particularly useful industrially can be obtained.

The alkanolamines represented by the general formula (II) according to the present invention have an alkanol structure corresponding to the starting alkylene oxide, wherein R ¹ , R ² , R
^A compound in which the substituents represented by ³ and R ⁴ are each independently constituted by a hydrogen atom, a methyl group or an ethyl group, and have 1 to 3 alkanol groups represented by m or n, that is, a monoalkanolamine And / or dialkanolamine and / or trialkanolamine. Such alkanolamines include:
Although not particularly limited, specific examples include monoethanolamine, diethanolamine, triethanolamine, and propanolamine.

As impurities generated in producing the alkanolamines, glycol ethers and the like can be mentioned. The glycol ethers are compounds in which the hydroxyl groups of alkanolamines are ethoxylated. Glycol ethers formed in the case of industrially particularly useful ethanolamines include monoethanolamine glycol ethers H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ OH,
Diethanolamine glycol ether (HOCH ₂ C
H ₂ ) HN (CH ₂ CH ₂ OCH ₂ CH ₂ OH), triethanolamine glycol ether (HOCH ₂ CH ₂ ) ₂ N
(CH ₂ CH ₂ OCH ₂ CH ₂ OH) and the like.

The heterogeneous catalyst for producing alkanolamine is not particularly limited.
Conventionally known heterogeneous catalysts such as solid acid catalysts such as acid-activated clay, silica alumina, molecular sieves, and zeolite, catalysts in which rare earth elements are supported on an inorganic refractory carrier, and crosslinked layered compound catalysts can be used. Among these heterogeneous catalysts for producing alkanolamines, catalysts in which a rare earth element is supported on an inorganic refractory carrier are preferred, and catalysts in which the inorganic refractory carrier is a layered clay compound are particularly preferred.

The acid used in the acid treatment of the heterogeneous catalyst for producing an alkanolamine which characterizes the present invention is not particularly limited as long as it can be removed by washing or thermal decomposition and does not remain in the catalyst. For example, volatile acids are preferred. Specifically, acetic acid is used as the organic acid,
Examples of oxalic acid, tartaric acid, benzoic acid, glycolic acid, and inorganic acids include hydrochloric acid, nitric acid, and carbonic acid. Among these acids, inorganic acids are preferred, and hydrochloric acid and nitric acid are particularly preferred.
These acids are usually used alone, but may be used in combination.

These acids can be used after being diluted with a solvent. The solvent is not particularly limited, and for example, water, methanol, ethanol and the like can be used. Among these solvents, water is desirable.
The concentration is preferably 0.01 to 10 stipulated,
In particular, 0.05 to 1 is preferred. If the thickness is less than 0.01, the processing time becomes extremely long, which is not practical. On the other hand, if the concentration is higher than 10N, the activity of the catalyst may decrease.

The amount of the catalyst with respect to the acid in the acid treatment of the present invention is not particularly limited, but is usually 0.1 to 50% by weight, preferably 0.5 to 15% by weight, based on the acid amount. Weight percent. If the amount of the catalyst is less than 0.1% by weight with respect to the amount of the acid, the production efficiency of the catalyst is reduced, while if it is more than 50% by weight, the acid treatment of the catalyst may not be sufficiently performed.

In the present invention, the temperature at which the catalyst is treated with an acid is not particularly limited.
Preferably, it is selected in the range of 10 to 100 ° C. If the temperature is lower than 0 ° C., the processing time becomes extremely long, which is not practical. on the other hand,
If the acid treatment is performed at a temperature higher than 150 ° C., the activity of the catalyst may be reduced. There is no particular restriction on the pressure,
The pressure is usually from normal pressure to 0.5 MPa, preferably normal pressure. Also, the time for contacting the catalyst with the acid is not particularly limited, but is usually 10 minutes to 24 hours, preferably 3 minutes.
The choice is from 0 minutes to 12 hours. If the time is shorter than 10 minutes, the acid treatment of the catalyst may not be sufficiently performed. The number of times of contact between the catalyst and the acid is not particularly limited, but is usually selected in the range of 1 to 10 times, preferably 1 to 5 times.

As a method for bringing the catalyst into contact with the acid at the time of the acid treatment in the present invention, a method of adding the acid to the catalyst and stirring in a slurry state or a method of circulating the acid by using the catalyst as a fixed bed can be used.

In the present invention, the method of removing the acid from the catalyst after the treatment with an acid is not particularly limited, and examples thereof include a method of washing the catalyst after the acid treatment and a method of performing a high-temperature treatment.

The washing method is not particularly limited, but a method of adding a solvent to the catalyst and stirring in a slurry state, or a method of circulating the solvent using the catalyst as a fixed bed can be used. The washing solvent is not particularly limited, and for example, water, methanol, ethanol and the like can be used. Washing is desirably continued until substantially no acid remains on the catalyst.

The method of the high-temperature treatment is not particularly limited, but is usually performed in air. When oxidation treatment is not particularly required, high-temperature treatment can be performed in an atmosphere of an inert gas such as nitrogen or in a vacuum. The catalyst is preferably subjected to a high temperature treatment at a temperature at which the acid is thermally decomposed and no longer remains on the catalyst, and usually a high temperature treatment in the range of 300 ° C to 700 ° C to obtain the catalyst. Heat treatment at a high temperature of 700 ° C. or more may lower the activity of the catalyst.

In the present invention, a particularly preferable method for removing the acid from the catalyst after the treatment with an acid is a method in which the catalyst after the acid treatment is washed by the above-mentioned washing method and then further treated by the above-mentioned high-temperature treatment method. .

The reactor used in the present invention is not particularly limited, and various conventionally known reactors, for example, a continuous flow reactor can be used. Also,
The method of supplying the raw materials to the reactor and the method of charging the catalyst are as follows:
It is not particularly limited. In the present invention, when the reaction is carried out in a liquid phase, the reaction pressure must be kept higher than the vapor pressure of the reaction solution at the highest temperature in the reactor. On the other hand, the recovery (removal of heat) of the reaction heat generated by the reaction between ammonia and the alkylene oxide can be performed by vaporizing a part of the liquid ammonia. That is, the heat of reaction due to the reaction between ammonia and the alkylene oxide (approximately 24
(kcal / mol) by controlling the reaction pressure below the vapor pressure of the reaction liquid at the maximum temperature expected from the temperature rise due to the temperature rise by kcal / mol, so that the reaction can be performed in a gas-liquid mixed phase state.

The method for recovering ammonia is not particularly limited, and various known methods can be used. It is preferable that a part of the liquid ammonia is vaporized by the reaction heat because the reaction heat can be efficiently used.

The amount of liquid ammonia to alkylene oxide is not particularly limited, but the molar ratio of alkylene oxide to ammonia is usually in the range of 1: 1 to 1:50, preferably in the range of 1: 2 to 1:40. Range. The reaction temperature is not particularly limited, but is usually in the range of 20 ° C to 300 ° C,
Preferably, it is selected from the range of 30 ° C to 200 ° C. When the reaction temperature is lower than 20 ° C., the reaction rate becomes low, and the amount of catalyst required for completely converting the alkylene oxide to the desired alkanolamine becomes relatively too large, so that the reactor needs to be enlarged. And the equipment cost may increase, and the alkanolamines may not be obtained at a low cost. On the other hand, when the reaction temperature is higher than 300 ° C., the temperature in the reactor becomes too high, and the amount of ammonia vaporized becomes too large, so that the liquid phase portion of the reaction solution becomes small, and the reaction between ammonia and alkylene oxide proceeds smoothly. It may not progress.

The operating pressure is usually 2 MPa to 30 MPa
a, preferably in the range of 4 MPa to 20 MPa. If the operation pressure is lower than 2 MPa, the amount of ammonia vaporized becomes too large, and therefore, the liquid phase portion of the reaction solution becomes small, and the reaction between ammonia and alkylene oxide may not proceed smoothly.

In addition, the hourly space velocity (L
HSV) is ¹ hr ^-1 , although it depends on the type and amount of catalyst used.
It is preferably in the range of ~100hr ^-1, 2hr ^-1 ~50hr
The range of ^-1 is more preferred. When the hourly space velocity is less than ¹ hr ^-1 , the contact time of ammonia and alkylene oxide with the catalyst becomes sufficiently long, so that the alkylene oxide can be efficiently converted into the desired alkanolamines, but The amount of catalyst required for complete conversion to alkanolamines is relatively too large, and the amount of alkanolamines produced per unit time is small. Is higher,
There is a possibility that the alkanolamines cannot be obtained at low cost. On the other hand, if the hourly space velocity is greater than 100 hr ^-1 , the time during which the ammonia and the alkylene oxide come into contact with the catalyst becomes short, and it may not be possible to convert the alkylene oxide into the desired alkanolamine.

[0045]

The following examples illustrate the process for producing ethanolamines primarily from ethylene oxide and ammonia. These examples are intended for illustrative purposes only and do not limit the invention.

The LHSV, the conversion of ethylene oxide and the selectivity of monoethanolamine in each example are defined as follows.

[0047]

(Equation 1)

[0048]

(Equation 2)

[0049]

(Equation 3)

[0050]

(Equation 4)

[0051] was added with stirring Montmorillonite 100g in Preparation Example of Catalyst A] of 0.05 mol / dm ³ aqueous lanthanum nitrate solution 5 dm ³ Example 1, stirring is carried out for 1 day at room temperature, filtered, the 5 dm ³ It was washed with pure water.
The cake was dried at 100 ° C. for one day, and then subjected to a high temperature treatment at 400 ° C. for 4 hours under an air flow. The obtained solid is 0.1 to 0.1
It was pulverized to a particle size of 0.2 mm to obtain a catalyst A.

Example 2 [Preparation Example of Catalyst B] 15 g of Contact A was added to 1 dm ³ of a 0.1 N hydrochloric acid aqueous solution, followed by stirring at room temperature for 10 hours. After the completion of the stirring, the catalyst was washed with deionized water until no chlorine ions were detected. Next, after drying at 120 ° C., the catalyst was subjected to a high temperature treatment at 400 ° C. for 4 hours under an air flow to obtain a catalyst B.

Example 3 [Preparation Example of Catalyst C] 15 g of Catalyst A was added to 1 dm ³ of 0.1 N hydrochloric acid aqueous solution, and the mixture was boiled for 1 hour. After the completion of boiling, the catalyst was washed with deionized exchanged water until no chlorine ions were detected. Then 1
After drying at 20 ° C., the mixture was subjected to high temperature treatment at 400 ° C. for 4 hours under an air flow to obtain Catalyst C.

Example 4 [Preparation Example of Catalyst D] 15 g of Catalyst A was added to 1 dm ³ of 0.1 N hydrochloric acid aqueous solution, and the mixture was boiled for 1 hour. After the boiling, decantation is performed, and 1 dm ³ of 0.1N hydrochloric acid aqueous solution is added to the mixture for 1 minute.
Boil for an hour. This operation was repeated, and boiling was performed four times. After the completion of boiling, the catalyst was washed with deionized exchanged water until no chlorine ions were detected. Next, after drying at 120 ° C., the catalyst was subjected to a high temperature treatment at 400 ° C. for 4 hours under an air flow to obtain a catalyst D.

Example 5 [Preparation Example of Catalyst E] 15 g of Catalyst A was added to 1 dm ³ of a 0.1 N aqueous nitric acid solution, and the mixture was boiled for 1 hour. After the boiling, decantation is performed, and 1 dm ³ of a 0.1N aqueous nitric acid solution is added thereto to add 1 dm ^3.
Boil for an hour. This operation was repeated, and boiling was performed four times. After completion of boiling, the catalyst was thoroughly washed with deionized water, dried at 120 ° C., and then subjected to a high temperature treatment at 500 ° C. for 4 hours under an air flow to obtain a catalyst E.

[0056] Example 6 [Preparation of Catalyst F] of 0.05 mol / dm ³ of yttrium nitrate aqueous 5 dm ³
Of montmorillonite was added thereto with stirring, stirred at room temperature for 1 day, filtered, and washed with 5 dm ³ of pure water. The cake was dried at 100 ° C. for one day, and then subjected to a high temperature treatment at 400 ° C. for 4 hours under an air flow. The obtained solid is put in 0.
It was ground to a particle size of 1-0.2 mm.

Thereafter, the above solid substance was added to 1 dm ³ of a 0.1 N aqueous nitric acid solution, and the mixture was boiled for 1 hour. After boiling, decantation was performed, and 1 dm ³ of a 0.1 N aqueous nitric acid solution was added, followed by boiling for 1 hour. This operation was repeated, and boiling was performed four times. After the boiling, the catalyst is thoroughly washed with deionized water, dried at 120 ° C., and then 500 ° C.
The catalyst was subjected to a high-temperature treatment under a flow of air for 4 hours to obtain a catalyst F.

Example 7 [Preparation Example of Catalyst G] Catalyst F was prepared except that a mixed aqueous solution containing 0.025 mol of lanthanum nitrate and 0.025 mol of iron nitrate in 1 dm ³ was used.
In the same manner as in the above, catalyst G was prepared.

Example 8 [Production Example of Alkanolamine] Catalyst B was charged into a stainless steel tube reactor (inner diameter: 10.7 mm) having an internal volume of 5.5 cm ³ . Ammonia and ethylene oxide were fed into the reaction vessel at a constant rate using a high-pressure pump by an ascending method, and the reaction vessel was heated in an oil bath. Reaction pressure was maintained at 14 MPa. The reaction solution was collected and analyzed by gas chromatography. Table 1 shows the results.

Examples 9 to 13 [Production of alkanolamine
Example] The reaction was carried out in the same procedure as in Example 8, except that the catalyst and the reaction conditions were changed. Table 1 shows the catalyst used, the reaction conditions, and the reaction results.

Comparative Example 1 A reaction was carried out in the same manner as in Example 8 except that the catalyst A was used. Table 1 shows the reaction results.

[0062]

[Table 1]

[0063]

According to the present invention, when an alkylene oxide is reacted with ammonia in the presence of a heterogeneous catalyst to produce an alkanolamine, the heterogeneous catalyst is treated with an acid in advance to produce an alkanolamine. The amount of generation of undesirable impurities such as ethers is reduced, and alkanolamines can be produced efficiently.

Claims (7)

[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 react with ammonia with 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
Is a method for preparing a catalyst used for producing an alkanolamine represented by (n + m), which represents an integer of 0 to 3 wherein 1 to 3), wherein the catalyst which is heterogeneous in the reaction system is an acid. A method for preparing a catalyst for producing an alkanolamine, wherein the catalyst is treated. 2. The method for preparing a catalyst for alkanolamine production according to claim 1, wherein after treating the heterogeneous catalyst with an acid, the acid is removed so as not to substantially remain on the catalyst. 3. The catalyst according to claim 1, wherein the heterogeneous catalyst comprises a rare earth element supported on an inorganic refractory carrier.
The method for preparing a catalyst for producing an alkanolamine according to the above. 4. The method according to claim 3, wherein the inorganic refractory carrier is a layered clay mineral. 5. The method for preparing a catalyst for producing an alkanolamine according to claim 1, wherein the acid is a volatile acid. 6. An alkanolamine-producing catalyst prepared by the method according to claim 1. Description: 7. An alkanolamine represented by the general formula (II) by reacting an alkylene oxide represented by the general formula (I) with ammonia in the presence of the catalyst according to claim 6. A method for producing an alkanolamine.