JPH07126228A - Production of alkanolamine and catalyst used therefor and preparation of catalyst - Google Patents

Abstract

PURPOSE:To provide the method capable of reducing the molar ratio of ammonia to an alkyleneoxide to a practical extent and of selectively producing the monoalkanolamine, and to provide a catalyst used therefor. CONSTITUTION:A 2-4C alkyleneoxide of formula I (R<1>-R<4> are H, methyl, ethyl) is reacted with ammonia in the presence of an inorganic solid catalyst having an average catalyst particle diameter of >=0.3mm, fine pore diameters of 10nm-10mum, and a fine pore volume of >=0.2-1cm<3>/mm to produce an alkanolamine of formula II. The catalyst is prepared by adding 20-200wt.% of a fine pore-forming agent (preferably crystalline cellulose) to a catalyst, molding the mixture, and subsequently burning off the fine pore-forming agent at a high temperature. A rare earth element carried on an inorganic refractory carrier, a crosslinked clay compound, and a microporous crystal having a fine pore diameter of 0.45-0.7nm is preferable as the active component of the catalyst. Since the ratio of the ammonia can be reduced, the cost for recovering the non-reacted ammonia can be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly useful for suppressing the product of addition of alkylene oxide to all active hydrogen when a alkylene oxide is aminated with ammonia to produce alkanolamines using a solid catalyst. , A monoalkanolamine selectively and with high productivity. In particular, it is useful in the production of ethanolamines which industrially aminates ethylene oxide with ammonia.

[0002]

2. Description of the Related Art As a method for producing alkanolamines by aminating alkylene oxide with ammonia, industrially, ethylene oxide and aqueous ammonia (20
(Ammonia concentration of about 40% by weight) is used to produce ethanolamines. In this method, in addition to monoethanolamine, diethanolamine and triethanolamine are by-produced, but the demand for triethanolamine is declining among these, so it is necessary to suppress the production of triethanolamine.
Therefore, the reaction is usually carried out with a large excess of ammonia such that the molar ratio of ammonia and ethylene oxide is about 3 to 5, but the selectivity of triethanolamine is still 10 to 2
It is 0% by weight or more and the selectivity of monoethanolamine is 50% by weight or less.

On the other hand, in a system in which water does not exist, alkylene oxide and ammonia hardly react. Therefore, the presence of a catalyst is essential for such reactions,
For example, a homogeneous catalyst of organic acids, inorganic acids, ammonium salts, etc. has been proposed (Patent No. 15 of Sweden).
8167). The homogeneous catalyst had a difficulty in separating the catalyst, and the performance was not sufficient. As an attempt to immobilize this homogeneous acid catalyst, an ion exchange resin in which a sulfonic acid group is immobilized on a resin has been proposed (Japanese Patent Publication No. 49-4772).
No. 8). This catalyst is relatively active and selective and is industrially practiced. However, the ion-exchange resin has a problem that the maximum operating temperature is low. The maximum temperature that can be used with commercially available ion-exchange resins is as low as about 120 ° C (see "Ion-exchange-theory and application guide-").
(Translated by Rokuro Kuroda and Masami Shibukawa, published by Maruzen Co., Ltd. in 1981, page 34) Therefore, if the reaction is carried out at a low molar ratio of ammonia and ethylene oxide, the temperature of the catalyst layer will exceed the heat resistant temperature due to the heat of reaction. However, there is a problem that the catalyst deteriorates when used under such temperature conditions for a long time. Therefore, it is difficult to set the molar ratio of ammonia and ethylene oxide to about 20 to 25 or less. Therefore, in order to overcome the drawback of the ion exchange resin that the heat resistance is low, an inorganic catalyst having excellent thermal stability has been investigated. U.S. Pat. No. 4,438,281 discloses that commonly used silica alumina is active. Industrial and Engineering Chemistry, Product Research and Development,
In 1986, Vol. 25, pp. 424-430, ion exchange resins and various zeolite catalysts are comparatively examined.
In terms of selectivity, it was not superior to the ion exchange resin. Further, JP-A-2-225446 discloses an acid activated clay catalyst. Even with these catalysts, the yield of monoethanolamine may be as high as 60% by weight or more. However, since the selectivity to monoalkanolamine is not sufficient in any case, the reaction is carried out with the molar ratio of ammonia and ethylene oxide being 20 to 30 times or more, and the equipment cost for recovering and recycling ammonia is required. It is large and practically difficult.

[0004]

An object of the present invention is to reduce the molar ratio of ammonia and alkylene oxide to a practically advantageous molar ratio, and to produce a monoalkanolamine with good selectivity even at that molar ratio. An object of the present invention is to provide an industrial method and a method for preparing a catalyst used therein.

As a result of intensive studies, the present inventors have found a catalyst exhibiting excellent performance in synthesizing alkanolamines from ammonia or amine and alkylene oxide in the liquid phase (Japanese Patent Application No. 4- 20208
No. 1, Japanese Patent Application No. 5-203038). However, these catalysts are evaluated in the case of a catalyst having an extremely small particle size, and if the catalyst is charged into the reactor of about 1 to 5 m as it is, the pressure loss becomes 3 to 50 MPa, which is a serious problem in practice. 0.3 in order to reduce the pressure loss of the catalyst layer to a practical level.
It is necessary to mold to a particle size of mm or more. Molding into such a particle size causes a problem that the catalytic performance is deteriorated.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the volume of pores having a pore diameter of 10 nm or more and 10 μm or less is 0.2 to 1 cm ³ / g. It was found that the above problems can be solved by using, and as a method for preparing such a catalyst,
The present invention has been completed by finding a method in which 20 to 200% by weight of the weight of the catalyst raw material after drying is mixed with the catalyst raw material and molded, and then removed by high temperature treatment.

Thus, according to the invention, the general formula (I) having 2 to 4 carbon atoms

[0008]

[Chemical 5] (In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group.), An alkylene oxide represented by the formula: 0.3 mm or more, pore diameter 10 nm or more 10 μm
The following formula (I) is characterized in that the reaction is carried out in the presence of an inorganic solid catalyst having a pore volume of 0.2 to 1 cm ³ / g.
I)

[0009]

[Chemical 6] (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I).) And a general formula having 2 to 4 carbon atoms ( I)

[0010]

[Chemical 7] (In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group.) By reacting an alkylene oxide represented by the general formula (II)

[0011]

[Chemical 8] (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I).) A catalyst used for producing an alkanolamine having an average catalyst particle size of 0. Inorganic solid catalyst for alkanolamine production, wherein the volume of pores having a pore diameter of 10 nm or more and 10 μm or less is 0.2 to 1 cm ³ / g, and
After the catalyst raw material was mixed with the pore-forming agent and molded, the pore-forming agent was removed by high temperature treatment to obtain a pore diameter of 10 nm or more.
The present invention relates to a method for preparing a catalyst for producing a noalkanolamine, which is characterized in that the volume of pores of μm or less is 0.2 to 1 cm ³ / g.

Since the catalyst according to the present invention is superior in monoalkanolamine selectivity to the heretofore known solid acid catalysts and has high heat resistance, the molar ratio of ammonia to alkylene oxide can be lowered. And
Since it is possible to reduce the pressure loss of the catalyst layer, it can be industrially favored.

The present invention will be described in detail below.

As the active component of the catalyst according to the present invention, a known solid catalyst component can be used, but if the original catalytic performance is not excellent, the effect of increasing the pore volume hardly appears. A catalyst in which a rare earth element is supported on an inorganic refractory carrier, a crosslinked clay compound, or microporous crystals having a pore size of 0.45 to 0.7 nm is preferable.

In the rare earth element-supported catalyst, the rare earth element is a lanthanoid group of the periodic table (lanthanum, cerium,
Praseodymium, neodymium, samarim, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium), scandium and yttrium are used.

The raw material for the rare earth element may be any that is insoluble in the reaction solution after being prepared by heat treatment, and in particular nitrates, sulfates, carbonates, acetates, oxalates, heteropolyacid salts, phosphates, Halides, oxides, hydroxides and the like can be used. As the carrier of the catalyst of the present invention, a specific surface area of 1 to 500 m ² / g and inorganic fire resistance may be used, and various known carriers such as natural products (diatomaceous earth,
Pumice, clay, etc.), single oxides (silica, alumina, titania, zirconia, etc.), complex oxides (silica alumina, titania silica, zirconia silica, perovskites, etc.), inorganic refractories (silicon carbide, silicon nitride, graphite, etc.) , Inorganic ion exchangers (SAPO, MeA
PO, metallosilicate, layered clay compound, etc.) can be used.

As a supporting method, an ion exchange method, an impregnation method, a kneading method or the like can be used.

The impregnation method is a method in which a molded carrier is put into a soluble rare earth element solution and heated to remove the solvent and carry it.

The kneading method is a method of molding a cake obtained by adding a rare earth element compound supported on a carrier powder and sufficiently kneading with a kneader using a small amount of solvent.

The ion exchange method is a method in which a carrier is added to a soluble rare earth element solution, alkali metal ions and the like at the exchange site of the ion exchanger are ion-exchanged with the rare earth element, and then the carrier is separated and carried. The ion exchange method is convenient for uniformly loading the rare earth element on the carrier.
In the ion exchange method, an inorganic ion exchanger is used as a carrier. Examples of inorganic ion exchangers include SAPO and M
Examples include eAPO, metallosilicate, and layered clay compound.

SAPO is crystalline aluminum phosphate (A
1PO) is a substance in which a part of phosphorus is replaced with silicon or a pair of aluminum and phosphorus is replaced with two silicons. M
Similarly, eAPO is a substance obtained by substituting aluminum of AlPO with a metal element (Co, Mg, Mn, Zn, Fe, etc.) other than silicon. Each has its own ion exchange site, SAPO-5, -11, -17, -40, MAP
O (Mg) -5, -11, -36, MnAPO-5,-
11, CoAPO-5, -36, FAPO (Fe) -3
4, ZAPO (Zn) -34, etc. are known (the-number is the same identification number as AlPO of the corresponding structure).

The metallosilicate is a substance in which the silicon portion in crystalline silicon oxide is replaced with a metal and has very uniform pores, and the charge balance is lost due to the replacement with the metal, resulting in ion exchange. The site exists. As the metallosilicate, specifically, a crystalline aluminosilicate known as zeolite is often used. As zeolite, A type, X type, Y type, L type, pentasil type (ZSM-
5, ZSM-11), mordenite, ferrierite, etc. can generally be used. As other metallosilicates, iron silicates, nickel silicates and the like can be used.

Smectite clay is known as the layered clay compound, and specifically, montmorillonite, saponite, hectorite, nontronite and the like are used.
These clay compounds also have an ion exchange site, and alkali metal ions such as sodium usually occupy this site, and they often exhibit basicity.

In preparation methods other than the kneading method, a soluble salt (nitrate, halide, heteropolyacid salt, etc.) is used as the catalyst raw material.

The loading ratio varies depending on the surface area of the carrier and the type of rare earth element, but is usually in the range of 1 to 50% by weight.

When loaded by the ion exchange method, it can be used without high temperature treatment, but it is usually 300 to 700 ° C.
High temperature treatment in the range of to obtain a catalyst. The high temperature treatment is usually carried out in the air, but when the oxidation treatment is not particularly required, the catalyst raw material can be thermally decomposed in an atmosphere of an inert gas such as nitrogen or in a vacuum.

The crosslinked clay catalyst is a so-called pillared clay, in which a relatively bulky metal oxide enters between silicate layers of a layered clay belonging to the smectite system to form a crosslinked structure, and the pillar forms a silicate layer. The distance is wide.

The pillar source may be a sol of a cationic oxide, a cationic hydroxide or a mixture thereof. Specific examples of the cationic oxide sol include titania sol produced by hydrolyzing titanium tetraisopropoxide with an aqueous hydrochloric acid solution. As the cationic hydroxide, polyaluminum chloride represented by (Al ₂ (OH) _n Cl _6-n ) _m (where n is about 3 and m is 10 or less) is partially dissolved in water. Polynuclear aluminum hydroxide hydrolyzed into aluminum; polynuclear aluminum hydroxide obtained by hydrolyzing Al, Cr, Bi, Fe chlorides, nitrates, and sulfates aqueous solutions by adding alkali little by little while stirring, Chromium hydroxide, bismuth hydroxide, iron hydroxide; and polynuclear zirconium hydroxide obtained by dissolving zirconyl oxychloride in water.

The microporous crystal is a crystal having very uniform pores, and examples thereof include the metallosilicate, SAPO, MeAPO, and the like described above as the carrier for the rare earth element.

As the pore-forming agent to be used, a substance which does not adversely affect the catalytic performance and can be removed by high temperature treatment can be used. Examples thereof include various ammonium salts such as ammonium nitrate and ammonium acetate, organic compounds such as oxalic acid and urea, and water-insoluble organic compounds such as various polymers and fibers. A water-insoluble organic compound can be preferably used in terms of pore generation efficiency and ease of molding. It suffices that it can be burned and removed by the high-temperature treatment of 1., and crystalline cellulose is particularly preferable in terms of handleability.

As the crystalline cellulose, powder obtained by crushing filter paper, powder obtained by crushing pulp, or the like is used.

When an organic pore-forming agent such as crystalline cellulose is used, it cannot be decomposed and removed by a simple heat treatment, so that it is burned and removed in a gas containing oxygen (it is convenient to use air).

When the pore volume of the catalyst is less than 0.2 cm ³ / g, the selectivity and activity are low, and when it is 1 cm ³ / g or more, the strength of the catalyst decreases, which is not practical.

Since the prepared catalyst is used in a fixed bed, it is compression-molded, or a binder is used to mold it to an average particle size of 0.3 mm or more and then to use it in the reaction. There are various definitions of the average particle diameter in the case of non-spherical shape, but here, it is defined as the diameter of a sphere having the same outer surface area.

Although the reason why the catalyst is effective for the present reaction is not completely clear, possible actions are described below.

The phenomenon that the activity decreases and the selectivity of the sequential reaction such as this reaction decreases as the particle size of the catalyst increases, the diffusion resistance in the catalyst particles cannot be ignored and the inside of the catalyst is sufficiently utilized. It is thought that it happens because it is not done. In order to reduce the diffusion resistance, it is considered effective to increase the catalyst porosity and decrease the labyrinth degree. Increasing the pore volume is believed to have an effect on this.

The starting alkylene oxide according to the present invention has the above general formula (I) having 2 to 4 carbon atoms.

[0038]

[Chemical 9] (In the formula, each of R ¹ , R ² , R ³ and R ⁴ independently represents a hydrogen atom, a methyl group or an ethyl group.), And examples thereof include ethylene oxide and propylene oxide. General formula (II) corresponding to these raw materials

[0039]

[Chemical 10] (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I)) to obtain an alkanolamine. Specific examples thereof include ethanolamine and propanolamine.

Since the reaction must be carried out in the liquid phase, the reaction pressure must be kept higher than the vapor pressure of the reaction liquid at the maximum temperature in the reactor.

Usually, the production of monoalkanolamines can be carried out in the temperature range of 50 to 300 ° C.
A preferred range is 80 to 200 ° C. Operating pressure is 1
Is about 20 MPa.

The molar ratio of ammonia to alkylene oxide is preferably in the range of 1: 1 to 40: 1.

Under the above conditions, the hourly space velocity (LH
It has been found that conditions where the SV) is from 4 to 15 or higher are particularly advantageous for the quantitative conversion of alkylene oxides.

[0044]

The present invention has the following effects.

First, since the catalyst according to the present invention has a high selectivity for the production of monoalkanolamines, the production ratio of alkanolamines is the same even if the ratio of ammonia and alkylene oxide is lower than those of other solid catalysts. The cost of recovering ammonia for the reaction is reduced. At the same time, since the total amount of the feed materials is reduced, the reaction system and the recovery system can be downsized, and the equipment cost can be reduced.

Further, since the pressure loss of the catalyst layer can be reduced, the power for supplying the raw materials can be saved, and the pump,
The pressure resistance of the reactor can be lowered, and the equipment cost can be further reduced.

[0047]

EXAMPLES The examples which follow show examples of the production of ethanolamines mainly from ethylene oxide and ammonia. The examples are intended for purposes of illustration and are not intended to limit the invention.

The LHSV, ethylene oxide conversion and monoethanolamine selectivity are defined as follows. Products other than ethanolamines were not produced, so the conversion of ethylene oxide (mol%)
Is equal to the overall yield (mol%) of (mono, di, tri) ethanolamine based on ethylene oxide.

[0049]

[Equation 1]

[0050]

[Equation 2]

[0051]

[Equation 3] The pore volume was determined by the mercury penetration method.

[Catalyst preparation example] Catalyst raw material powder a This is an example in which lanthanum is used as a rare earth element and montmorillonite is used as a carrier. Was added with stirring montmorillonite 2kg lanthanum nitrate aqueous solution 100 dm ³ of 0.05 mol / dm ^3, stirring is carried out for 1 day at room temperature, filtered, 1
It was washed with pure water of 00 dm ³ . This cake was dried at 100 ° C. for 1 day and then pulverized to 200 mesh or less to obtain a catalyst raw material powder a.

Catalyst A To 100 g of the catalyst raw material powder a, 30 g of Avicel (Crystalline Cellulose manufactured by Asahi Chemical Industry Co., Ltd.) and water were added and kneaded in the same weight as the total weight of the catalyst raw material powder and Avicel.
It was molded into a pellet having a diameter of 0.5 mm and a length of 2 to 5 mm by an extruder and dried at 100 ° C. for 1 day. The equivalent particle size was 1 to 1.6 mm.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.26 cm ³ / g.

Catalyst B A catalyst was prepared in the same manner as catalyst A except that the amount of Avicel used was 60 g.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.4 cm ³ / g.

Catalyst C A catalyst was prepared in the same manner as catalyst A except that the amount of Avicel used was 100 g.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.7 cm ³ / g.

Catalyst D A catalyst was prepared in the same manner as catalyst A except that 30 g of filter paper powder was added and mixed with 100 g of catalyst raw material powder a.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.3 cm ³ / g.

Catalyst E A catalyst was prepared in the same manner as the catalyst A except that 150 g of ammonium nitrate was added to 100 g of the catalyst raw material powder a and mixed and kneaded.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.32 cm ³ / g.

Catalyst F An example of a crosslinked clay is a montmorillonite catalyst using zirconia as pillars. 0.4 mol / dm ³ of aqueous solution of zirconium oxychloride 30Dm ³ was aged for 48 hours at 60 ° C.. After thoroughly dispersing 900 g of montmorillonite in ³⁰ dm ³ of distilled water, the aged zirconium oxychloride aqueous solution was added dropwise and well stirred. After completion of dropping, the mixture was heated at 65 ° C. for 3 hours while stirring as it was. After the heating, it was washed with distilled water until no zirconium ions were detected, and dried with a hot air dryer at 60 ° C. This 2
Milled to less than 00 mesh, 100 g of this and Avicel 6
After adding 160 g of pure water again to 0 g and kneading with a kneader, it was molded into a cylindrical shape having a diameter of 0.5 mm and a length of 2 to 10 mm by an extruder. This was subjected to a high temperature treatment at 450 ° C under air flow to obtain a catalyst.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.38 cm ³ / g.

Catalyst G This is an example of using iron silicate as a microporous crystal.

Pentacyl-type iron silicate (XRD analysis shows that the crystal structure is MFI type, Fe / Si atomic ratio = 1 /
25, ion exchange with ammonium ion) 10 to 20 g
Weight% montmorillonite was added as a binder, 12 g of Avicel was added, and a small amount of water was used and kneaded well in a mortar. After drying at 120 ° C for 12 hours, under air flow 500
After high temperature treatment at ℃, it was crushed to 0.7 to 1 mm to obtain a catalyst.

The pore volume with a pore diameter of 10 nm to 10 μm was 0.35 cm ³ / g.

Comparative Catalyst H To 100 g of the catalyst raw material powder a, pure water was added again in the same amount as the powder, and the mixture was kneaded with a kneader and then the diameter was 0.5 m with an extruder.
m, molded into pellets of 2 to 5 mm in length, and 1 at 100 ° C
Day dried. After that, high temperature treatment was performed in air at 500 ° C. for 5 hours to obtain a catalyst. The equivalent particle size was 1 to 1.6 mm.

The pore volume with a pore diameter of 10 nm to 10 μm was 0.1 cm ³ / g.

Comparative catalyst I Prepared in the same manner as catalyst G except that Avicel was not added during kneading and pure water used was 100 g.

The volume of pores having a pore diameter of 10 nm to 10 μm was 0.11 cm ³ / g.

Comparative Catalyst J Prepared in the same manner as Catalyst G except that Avicel was not added during kneading.

The pore volume with a pore diameter of 10 nm to 10 μm was 0.09 cm ³ / g.

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

Examples 2 to 5 The reaction was carried out in the same procedure as in Example 1 except that the catalysts were changed to B, C, D and E. The reaction conditions and results are shown in Table 1.

Comparative Example 1 The reaction was carried out by the same procedure as in Example 1 except that the catalyst was changed to H.

In these comparative examples, when the catalyst particle size becomes large and the pore volume of 10 nm to 10 μm is small,
This is an example showing that catalytic activity and selectivity are lowered. Since the catalytic activity is lowered, the reaction is carried out at a higher reaction temperature than the corresponding examples. The reaction conditions and results are shown in Table 1.
Shown in.

Example 6 The reaction was carried out in the same procedure as in Example 1 except that the catalyst was changed to F. The reaction conditions and results are shown in Table 2.

Comparative Example 2 The reaction was carried out in the same procedure as in Example 1 except that the catalyst was changed to I. The reaction conditions and results are shown in Table 2.

Example 7 The reaction was carried out by the same procedure as in Example 1 except that the catalyst was changed to G. The reaction conditions and results are shown in Table 3.

Comparative Example 3 The reaction was carried out in the same procedure as in Example 1 except that the catalyst was changed to J. The reaction conditions and results are shown in Table 3.

Examples 1 to 5 correspond to Comparative Example 1, Example 6 corresponds to Comparative Example 2, and Example 7 corresponds to Comparative Example 3.

[0083]

[Table 1]

[0084]

[Table 2]

[0085]

[Table 3]

Claims (3)

[Claims] 1. A compound of the general formula (I) having 2 to 4 carbon atoms: (In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group.), An alkylene oxide represented by the formula: 0.3 mm or more, pore diameter 10 nm or more 10 μm
The following formula (I) is characterized in that the reaction is carried out in the presence of an inorganic solid catalyst having a pore volume of 0.2 to 1 cm ³ / g.
I) [Chemical formula 2] (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I).) A method for producing an alkanolamine. 2. General formula (I) having 2 to 4 carbon atoms: (In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group.) By reacting an alkylene oxide represented by the general formula (II): Chemical 4] (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I).) A catalyst used for producing an alkanolamine having an average catalyst particle size of 0. An inorganic solid catalyst for producing an alkanolamine, wherein the volume of pores having a pore diameter of 10 nm or more and 10 μm or less is 0.2 to 1 cm ³ / g and is 0.3 mm or more. 3. A catalyst raw material is mixed with 20 to 200% by weight of a pore-forming agent, and the mixture is molded. Then, the pore-forming agent is burned and removed by high-temperature treatment to reduce the volume of pores having a diameter of 10 nm to 10 μm to 0. A method for preparing a catalyst for producing an alkanolamine, characterized in that the content is 0.2-1 cm ³ / g.