JP2793485B2 - Process for producing alkanolamine, catalyst used therefor, and process for preparing catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the production of alkanolamines by amination of an alkylene oxide with ammonia using a solid catalyst, and particularly to the suppression of the product of addition of an alkylene oxide to all active hydrogens. And a method for selectively producing monoalkanolamines with high productivity. Particularly, it is useful in the production of ethanolamines for aminating ethylene oxide with ammonia industrially.

[0002]

2. Description of the Related Art As a method for producing an alkanolamine by aminating an alkylene oxide with ammonia, industrially, ethylene oxide and aqueous ammonia (20%) are used.
(Ammonia concentration of ４０40% by weight) to produce ethanolamines. In this method, in addition to monoethanolamine, diethanolamine and triethanolamine are by-produced. Among them, the demand for triethanolamine has declined, and thus it is required to suppress the production of triethanolamine.
For this reason, usually, the reaction is carried out with a large excess of ammonia such that the molar ratio of ammonia to 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 also 50% by weight or less.

On the other hand, in a system in which water does not exist, the alkylene oxide hardly reacts with ammonia. Therefore, the presence of a catalyst is indispensable for such a reaction,
For example, homogeneous catalysts such as organic acids, inorganic acids and ammonium salts have been proposed (Swedish Patent No. 15).
No. 8167). In the case of a homogeneous catalyst, there were difficulties 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 sulfonic acid groups are immobilized on the resin has been proposed (Japanese Patent Publication No. 49-4772).
No. 8). 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-guide to theory and application-”
(Translated by Rokuro Kuroda and Masami Shibukawa, published by Maruzen Co., Ltd. in 1981, p. 34) Therefore, when the reaction is carried out with a low molar ratio of ammonia and ethylene oxide, the temperature of the catalyst layer exceeds the heat resistance temperature due to heat of reaction. However, when used under such temperature conditions for a long time, there is a problem that the catalyst is deteriorated. For this reason, it is difficult to reduce the molar ratio of ammonia to ethylene oxide to about 20 to 25 or less. Therefore, in order to overcome the drawback of the ion exchange resin having low heat resistance, an inorganic catalyst having excellent thermal stability has been studied. U.S. Pat. No. 4,438,281 discloses that commonly used silica alumina exhibits activity. Industrial and engineering chemistry, product research and development,
In 1986, Vol. 25, pp. 424-430, ion exchange resins and various zeolite catalysts are compared and studied.
It was not superior to ion exchange resins in terms of selectivity. Japanese Patent Application Laid-Open No. 225446/1990 discloses an acid-activated clay catalyst. In some of these catalysts, the yield of monoethanolamine is as high as 60% by weight or more. However, since the selectivity to monoalkanolamine is not sufficient in all cases, the reaction is carried out at a molar ratio of ammonia to ethylene oxide of 20 to 30 times or more, and equipment costs for recovering and recycling ammonia are reduced. There are many practical difficulties.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the molar ratio of ammonia to alkylene oxide to a practically advantageous molar ratio, and to produce a monoalkanolamine with high 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 in the method.

As a result of intensive studies, the present inventors have found a catalyst exhibiting excellent performance in synthesizing alkanolamines from ammonia or an amine and an alkylene oxide in a liquid phase (Japanese Patent Application No. Hei. 20208
No. 1, Japanese Patent Application No. 5-203038). However, these catalysts are evaluated for catalysts having an extremely small particle size. If the catalyst is charged into a reactor of about 1 to 5 m as it is, the pressure loss becomes 3 to 50 MPa, which is a serious problem in practical use. 0.3 to reduce the catalyst layer pressure loss 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 catalyst performance is reduced.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have found that the volume of pores having a pore diameter of 10 nm or more and 10 μm or less is 0.2-1 cm ³ / g. Is found to be able to solve the above problems, and as a method for preparing such a catalyst,
A method for removing 20 to 200% by weight of a pore forming agent based on the weight of the dried catalyst raw material into the catalyst raw material and then removing the mixture by high-temperature treatment was found, and the present invention was completed.

That is, according to the present invention, general formula (I) having 2 to 4 carbon atoms

[0008]

Embedded image (Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group.) 0.3 mm or more, pore diameter 10 nm or more and 10 μm
The reaction is carried out in the presence of an inorganic solid catalyst having the following pore volume of 0.2 to 1 cm ³ / g.
I)

[0009]

Embedded image (Wherein, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I)), and the general formula (C) having 2 to 4 carbon atoms. I)

[0010]

Embedded image (Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group), and reacting the alkylene oxide represented by the general formula (II)

[0011]

Embedded image (Wherein, R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I)), wherein the catalyst has 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 0.3 mm or more and a pore diameter of 10 nm or more and 10 μm or less is 0.2 to 1 cm ³ / g;
After mixing and molding the pore forming agent with the catalyst raw material, the pore forming agent is removed by high-temperature treatment, and the pore diameter is 10 nm or more.
The present invention relates to a method for preparing a catalyst for producing noalkanolamine, wherein the volume of pores having a size of μm or less is set to 0.2 to 1 cm ³ / g.

The catalyst according to the present invention has higher selectivity for monoalkanolamine and higher heat resistance than the conventionally known solid acid catalyst, so that the molar ratio of ammonia to alkylene oxide can be reduced. And
Since it is possible to reduce the pressure loss of the catalyst layer, it can be carried out industrially advantageously.

Hereinafter, the present invention will be described in detail.

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 is hardly exhibited. A catalyst in which a rare earth element is supported on an inorganic refractory carrier, a crosslinked clay compound, or a microporous crystal having a pore diameter of 0.45 to 0.7 nm is preferable.

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

The rare earth element raw material may be any material that becomes insoluble in the reaction solution after being prepared by heat treatment, and particularly includes nitrates, sulfates, carbonates, acetates, oxalates, heteropolyacid salts, phosphates, and the like. A halide, an oxide, a hydroxide, or the like can be used. The carrier of the catalyst of the present invention may have a specific surface area of 1 to 500 m ² / g and inorganic refractory, and may be any of various known carriers such as natural products (diatomaceous earth,
Pumice, clay, etc.), single oxides (silica, alumina, titania, zirconia, etc.), composite oxides (silica alumina, titania silica, zirconia silica, perovskite, 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 charged into a soluble rare earth element solution, and the solvent is removed by heating to carry the carrier.

The kneading method is a method in which a rare earth element compound supported on a carrier powder is added, and a kneading machine is sufficiently kneaded using a small amount of a solvent to form a cake.

The ion exchange method is a method in which a carrier is put into a soluble rare earth element solution, alkali metal ions and the like at an exchange site of the ion exchanger are ion-exchanged with the rare earth element, and then separated from the solution and supported. The ion exchange method is convenient for uniformly supporting 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, M
eAPO, metallosilicate, layered clay compound, and the like.

SAPO is a crystalline aluminum phosphate (A
lPO) is a substance in which part of phosphorus is replaced with silicon or a pair of aluminum and phosphorus is replaced with two silicons. M
eAPO is a substance in which aluminum of AlPO is replaced by a metal element other than silicon (such as Co, Mg, Mn, Zn, or Fe). Each has an 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).

Metallosilicate is a substance in which the silicon portion of crystalline silicon oxide is replaced with a metal, has extremely uniform pores, and the charge balance is lost by the amount of the metal replaced, so that ion exchange is performed. Site exists. As the metallosilicate, specifically, a crystalline aluminosilicate known as zeolite is often used. As zeolites, A type, X type, Y type, L type, pentasil type (ZSM-
5, ZSM-11, etc.), mordenite, ferrierite and the like can be generally used. As other metallosilicates, iron silicate, nickel silicate and the like can be used.

As the layered clay compound, smectite clay is known, and specifically, montmorillonite, saponite, hectorite, nontronite and the like are used.
These clay compounds also have an ion exchange site, and usually an alkali metal ion such as sodium occupies this site, and often exhibits basicity.

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

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

When supported by an ion exchange method, it can be used without high-temperature treatment.
The catalyst is subjected to a high temperature treatment in the range described above. The high-temperature treatment is usually performed in the air, but when the oxidation treatment is not particularly required, the catalyst 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. A relatively bulky metal oxide enters between the silicate layers of the layered clay belonging to the smectite system to form a crosslinked structure. The spacing is widening.

The pillar source may be a cationic oxide sol, 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, a polyaluminum chloride represented by (Al ₂ (OH) _n Cl _6-n ) _m (where n is about 3 and m is 10 or less) is dissolved in water and partially Polynuclear aluminum hydroxide obtained by hydrolyzing an aqueous solution of each of chlorides, nitrates, and sulfates of Al, Cr, Bi, and Fe by adding a small amount of an alkali while stirring the solution; Chromium hydroxide, bismuth hydroxide, iron hydroxide; polynuclear zirconium hydroxide obtained by dissolving zirconyl oxychloride in water;

The microporous crystal is a crystal having very uniform pores, and examples of the rare earth element carrier include the above-mentioned metallosilicate, SAPO, MeAPO and the like.

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, ease of molding, and the like, and as the water-insoluble organic compound has a certain degree of hygroscopicity, it is a fine powder and is several hundred degrees. It is only necessary to be able to be removed by combustion in the high-temperature treatment, and crystalline cellulose is particularly preferable in terms of handleability.

As the crystalline cellulose, a powder obtained by pulverizing filter paper or a powder obtained by pulverizing pulp 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 burnt and removed in a gas containing oxygen (use of air is convenient).

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

The prepared catalyst is subjected to compression molding for use in a fixed bed, or molding to have an average particle diameter of 0.3 mm or more by using a binder, and then subjecting it to a reaction. There are various definitions of the average particle size in the case of not being spherical, 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 in the present reaction is not completely clear, the possible actions are described below.

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

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

[0038]

Embedded image (Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group), and examples thereof include ethylene oxide and propylene oxide. The general formula (II) corresponding to these raw materials

[0039]

Embedded image (Wherein R ¹ , R ² , R ³ and R ⁴ are the same as those in the general formula (I)). Specific examples include ethanolamine and propanolamine.

Since the reaction must be 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.

Usually, the production of monoalkanolamines can be carried out in a temperature range of 50 to 300 ° C.
A preferred range is 80-200 ° C. Operating pressure is 1
２０20 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
Conditions with an SV) of 4 to 15 or more have proven to be particularly advantageous for the quantitative conversion of alkylene oxides.

[0044]

The present invention has the following effects.

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

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

[0047]

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

The LHSV, the conversion of ethylene oxide and the selectivity of monoethanolamine are defined as follows. No products other than ethanolamines were formed, and thus 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 a mercury intrusion method.

[Catalyst Preparation Example] Catalyst raw material powder a This is an example using lanthanum as a rare earth element and montmorillonite 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 00 dm ³ of pure water. The cake was dried at 100 ° C. for 1 day, and pulverized to 200 mesh or less to obtain a catalyst raw material powder a.

Catalyst A 30 g of Avicel (crystalline cellulose manufactured by Asahi Kasei Kogyo Co., Ltd.) and water were added to 100 g of the catalyst raw material powder a at the same weight as the total weight of the catalyst raw material powder and Avicel, and kneaded.
The mixture was formed 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 one day. The equivalent particle size was 1 to 1.6 mm.

The pore volume at 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 changed to 60 g.

The pore volume at 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 pore volume at 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 the catalyst A, except that 30 g of filter paper powder was added to 100 g of the catalyst raw material powder a, mixed and kneaded.

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

Catalyst F A montmorillonite catalyst using zirconia as a pillar in the example of the crosslinked clay. 0.4 mol / dm ³ of aqueous solution of zirconium oxychloride 30Dm ³ was aged for 48 hours at 60 ° C.. After 900 g of montmorillonite was well dispersed in ³⁰ dm ³ of distilled water, aged aqueous zirconium oxychloride was added dropwise and stirred well. After completion of the dropwise addition, the mixture was heated at 65 ° C. for 3 hours while stirring as it was. After the completion of the heating, the substrate was washed with distilled water until no zirconium ions were detected, and dried with a hot air drier at 60 ° C. This is 2
100 g and Avicel 6
After adding 160 g of pure water again to 0 g and kneading with a kneader, the mixture 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 treated at a high temperature of 450 ° C. in a stream of air to obtain a catalyst.

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

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

Pentasil 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
By weight, montmorillonite was added as a binder, 12 g of Avicel was added, and the mixture was kneaded well in a mortar using a small amount of water. After drying at 120 ° C. for 12 hours, 500
After high temperature treatment at ℃, it was crushed to 0.7 to 1 mm to obtain a catalyst.

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

Comparative Catalyst H Pure water was again added to 100 g of the catalyst raw material powder a in the same amount as the powder, and the mixture was kneaded with a kneader and then extruded with a diameter of 0.5 m using an extruder.
m, molded into a pellet with a length of 2-5 mm.
Sun dried. Then, it was subjected to high temperature treatment 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 at a pore diameter of 10 nm to 10 μm was 0.1 cm ³ / g.

Comparative Catalyst I A catalyst was prepared in the same manner as the catalyst F , except that Avicel was not added during kneading, and pure water used was changed to 100 g.

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

Comparative Catalyst J A catalyst was prepared in the same manner as the catalyst G, except that Avicel was not added during kneading.

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

[Production Example of Alkanolamine] Example 1 A reactor made of a stainless steel tube (inner diameter: 10.7 mm) having an inner volume of 5.5 cm ³ was charged with the catalyst A. 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. The pressure was maintained at 14 MPa. The reaction solution was collected and analyzed by gas chromatography. Table 1 shows the reaction conditions and results.

Examples 2 to 5 The reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to B, C, D and E. Table 1 shows the reaction conditions and results.

Comparative Example 1 A reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to H.

These comparative examples show that when the particle size of the catalyst is large, the pore volume of 10 nm to 10 μm is small,
It is an example showing that catalyst activity and selectivity are reduced. The reaction is carried out at a higher reaction temperature than in the corresponding example because the catalytic activity has decreased. Table 1 shows the reaction conditions and results.
Shown in

Example 6 A reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to F. Table 2 shows the reaction conditions and results.

Comparative Example 2 A reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to I. Table 2 shows the reaction conditions and results.

Example 7 A reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to G. Table 3 shows the reaction conditions and results.

Comparative Example 3 A reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to J. Table 3 shows the reaction conditions and results.

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]

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 215/08 B01J 21/16 C07C 213/04 C07B 61/00 300

Claims (3)

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