JPH0733718A - Production of alkanolamine by amination of alkylene oxide - Google Patents

Abstract

PURPOSE:To produce an alkanolamine compound in high selectivity by using a catalyst composed of a crystalline metallosilicate containing a specific metal taken into the silicate and aminating an alkylene oxide with ammonia or an amine. CONSTITUTION:An alkanolamine of formula III is produced by reacting an alkylene oxide of formula I (R<1> to R<4> are H, methyl or ethyl) with ammonia or amine of formula II (R<5> is H or 1-5C alkyl). The reaction is carried out in the presence of a catalyst consisting of a crystalline metallosilicate containing at least one kind of metal selected from Fe, Co, Ni, B, Ga, Cr, Sc, Ti and Ge taken in the lattice. The metal is especially preferably Fe. Since the catalyst has excellent monoalkanolamine selectivity and high heat-resistance, the molar ratio of the ammonia or amine to the monoalkylene oxide can be decreased to reduce the recovering cost of unreacted ammonia or amine. At the same time, the total amount of the feeding raw materials can be decreased to reduce the size of the apparatus and save the apparatus cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing alkanolamines by aminating alkylene oxide with ammonia or amine using a catalyst. The production method of the present invention is suitable for use in, for example, a production method of ethanolamines in which ethylene oxide is industrially aminated with ammonia.

[0002]

2. Description of the Related Art A method for producing alkanolamines by aminating alkylene oxide with ammonia or amine is industrially conducted by reacting ethylene oxide with aqueous ammonia to produce ethanolamines. There is. In this method, in addition to monoethanolamine, diethanolamine and triethanolamine are by-produced. Among these products, the demand for triethanolamine is declining, and it is required to suppress the production of triethanolamine. If the molar ratio of ammonia to ethylene oxide (ammonia / ethylene oxide) is increased, the selectivity of monoethanolamine tends to increase. Usually, the reaction is carried out at a molar ratio of about 3 to 5, but the monoethanolamine does not react with monoethanolamine. The selectivity is 50 wt% or less, and the triethanolamine selectivity is 10 to 20 wt% or more.

On the other hand, in a system without water, the reaction rate of alkylene oxide and ammonia is extremely low, and the selectivity of the mono-adduct is extremely low. Therefore, the presence of a catalyst is indispensable for such a reaction, and various catalysts such as organic acids, inorganic acids, ammonium salts, ion exchange resins, and zeolites have been studied (for example, Swedish Patent No. 158167). No. JP-A-49-4772
No. 8, Industrial and Engineering
Chemistry Product Research and Development, 1986, Vol. 25, pp. 424-430, U.S. Pat. No. 4,438,281). Among these methods, the selectivity of monoethanolamine is 60% by weight to 90% by weight.
Some of them are as high as several% by weight, but in order to obtain such a high monoethanolamine selectivity, the reaction is carried out with the molar ratio of ammonia to ethylene oxide being 30 times or more. However, under such a reaction condition, the equipment cost for recovering and recycling ammonia is increased, which is not practical. In addition, ion exchange resins tend to obtain higher monoethanolamine selectivity than zeolites, but ion exchange resins have a problem with heat resistance.Therefore, the use of ion exchange resins reduces the molar ratio of ammonia to ethylene oxide. You cannot do it.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a monoalkanolamine with good selectivity, which can reduce the molar ratio of ammonia or amine to alkylene oxide to a practical level. .

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that excellent performance is obtained in the synthesis of alkanolamines from ammonia or amine and alkylene oxide in a liquid phase. We have found a catalyst that works and have completed the present invention. That is, the present invention provides the following general formula (I) having 2 to 4 carbon atoms in the presence of a catalyst.

[Chemical 4] (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 an alkylene oxide represented by the following general formula (II)

Embedded image R ⁵ —NH ₂ (II) (wherein, R ⁵ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) and is reacted with ammonia or an amine represented by the following general formula (III)

[Chemical 6] (In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are represented by the formulas (I) and (I
It is the same as I). ) In the method for producing alkanolamines, the catalyst Fe, C in the lattice is used.
A method for producing alkanolamines is characterized by using a crystalline metallosilicate incorporating at least one of o, Ni, B, Ga, Cr, Sc, Ti and Ge.

Since the catalyst according to the present invention is superior in monoalkanolamine selectivity to the conventionally known solid acid catalyst and has high heat resistance of the catalyst, it is necessary to reduce the molar ratio of ammonia or amine to alkylene oxide. Is also possible.

The present invention will be described in detail below. Fe, C incorporated into the crystalline metallosilicate lattice of the catalyst
The atomic ratio of metal such as o, Ni, B, Ga, Cr, Sc, Ti and Ge to silicon is preferably 1 to 10 to 1: 300.
It is 0, more preferably 1 to 20 to 1: 100. If the atomic ratio of silicon to these metals is less than 1:10, the amount of metal in the lattice is too large and the crystal structure of the metallosilicate becomes unstable. On the other hand, if it is more than 3000, the amount of metal is too small and the active sites become The density is too small and the reaction activity is significantly reduced.

In the as-synthesized crystalline metallosilicate, alkali metal ions are contained in its ion exchange sites. In that state, there are almost no acid sites and the activity is low. Therefore, it is desirable to exchange the alkali metal ions with protons, ammonium ions, polyvalent cations, etc. to increase the activity.

The method for preparing the crystalline metallosilicate according to the present invention is described in JOURNAL O
F CATALYSIS) 98: 491-501 (1986) and the like, and is prepared by such a known method in the present invention. For example, there is used a method in which a silica source as a raw material and a metal source to be incorporated into the lattice are mixed and hydrothermal synthesis is performed using an organic template agent. In the synthesized crystalline metallosilicate, the alkali metal is ion-exchanged with a proton, an ammonium ion or a polyvalent cation, if necessary. If necessary, as the outer surface treatment, steaming treatment at high temperature, silicon tetrachloride treatment, alkoxysilane treatment, or the like is performed. When the prepared catalyst is used in a fixed bed, it is simply compression-molded, or a binder is used for molding and then subjected to the reaction.

The reason why the crystalline metallosilicate is effective as a catalyst for this reaction is not completely clear, but its possible actions are described below. Crystalline metallosilicates are widely known as substances having micropores, and the catalytic action is that the metal incorporated in the lattice causes the generation of acid sites and the reaction within the micropores. It is characterized by so-called shape selectivity, in which reaction results vary depending on size and shape. Further, with respect to zeolites generally known as aluminosilicate, the crystalline metallosilicate used in the present invention is in a form in which aluminum in the zeolite lattice is replaced with another metal, and the nature of the acid point caused by the metal Can be changed by changing the type of metal. Taking the reaction of ammonia and ethylene oxide as an example of the reaction for producing alkanolamines, first, monoethanolamine is produced, then ethylene oxide is subjected to an addition reaction to produce diethanolamine, and further ethylene oxide is subjected to an addition reaction to produce triethanolamine. To generate. As the number of ethylene oxide added increases, the molecular size of the product increases. Therefore, if the reaction is carried out in the micropores of the crystalline metallosilicate catalyst of the present invention capable of recognizing this size, it is considered that a large molecule is not produced and a product having a small addition mole number of ethylene oxide is selectively produced. To be In addition, it is considered that the shape selectivity and the selectivity can be further improved by changing the metal species to control the properties of the acid sites.

The production of alkanolamines can be carried out in a continuous slurry bed reactor or a continuous flow fixed bed reactor. A fixed bed is preferred for practical reasons. Usually, alkylene oxide and ammonia or amines are fed as an ascending method into a reactor filled with a catalyst. The amount of catalyst is preferably an amount sufficient to exert the desired contact effect.

The alkylene oxide as a raw material according to the present invention is an alkylene oxide represented by the above general formula (I) having 2 to 4 carbon atoms, and examples thereof include ethylene oxide and propylene oxide. In addition to ammonia as the other raw material, the amines are primary amines represented by the general formula (II), such as methylamine, ethylamine and propylamine. The alkanolamine represented by the general formula (III) is obtained corresponding to these raw materials. Specific examples include ethanolamine, N
-Methylethanolamine, N-ethylethanolamine, N-propylethanolamine, propanolamine, N-methylpropanolamine, N-ethylpropanolamine and the like are exemplified.

During the reaction, it is desirable to carry out the reaction at a maximum temperature at which the reaction mixture is formed, at least under a pressure higher than the vapor pressure of the raw materials so that the reaction liquid maintains a liquid phase state. Usually, the production of monoalkanolamines is 50 ° C to 30 ° C.
It can be carried out in the temperature range of 0 ° C. A preferred range is 80 to 250 ° C. Operating pressure is 1 ~ 30MPa
Is.

The molar ratio of ammonia or amine to alkylene oxide is preferably in the range of 1: 1 to 40: 1.
Also in the present invention, if the ratio of ammonia or amine to alkylene oxide is increased, the selectivity of monoalkanolamines is increased, but the unreacted amount of ammonia or amine is increased, and ammonia or amine is recovered and used for circulation. The equipment will be large-scale. On the other hand, if the ratio of ammonia or amine to alkylene oxide is reduced, the amount of unreacted ammonia or amine will decrease and the equipment for recovering and recycling ammonia or amine will be simpler. The selectivity of the class becomes small. The ratio of ammonia or amine to alkylene oxide may be appropriately set in consideration of the requirement for the selectivity of monoalkanolamines and the requirement for equipment for recovering and recycling ammonia or amine. Also, 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.

[0015]

The present invention has the following effects. First, since the catalyst according to the present invention has high selectivity for the production of monoalkanolamines, even if the ratio of ammonia or amine to alkylene oxide is lower than that of other solid acid catalysts, the same production ratio of monoalkanolamines is obtained. Therefore, the recovery cost of unreacted ammonia or amine 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. Furthermore, this crystalline metallosilicate catalyst has heat resistance and can stably produce alkanolamines.

[0016]

EXAMPLES The examples which follow show examples of the preparation of ethanolamines mainly from ethylene oxide and amines. These examples are intended for purposes of illustration and are not intended to limit the invention. The LHSV, the conversion rate of ethylene oxide and the selectivity of monoalkanolamine are defined as follows. In addition,
No products other than ethanolamines have been produced, so the conversion of ethylene oxide (mol%) is equal to the overall yield (mol%) of the (mono, di, tri) alkanolamine based on ethylene oxide.

[0017]

[Equation 1]

Catalyst A Pentasil-type iron silicate (the crystal structure was ZSM-5 type from the analysis by X-ray diffraction) Fe / Si atomic ratio = 1/25 Ion exchange with proton Specific surface area 350 m ² / g

(Examples 1 and 2) Catalyst A was filled in a stainless steel tube reactor (inner diameter: 10.7 mm) 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. Pressure is 14
It was maintained at MPa. The reaction solution was collected and analyzed by gas chromatography.

Example 3 The reaction was carried out in the same procedure as in Example 1 except that the reaction starting amine in Example 1 was changed from ammonia to n-propanolamine and the reaction conditions were changed.

(Comparative Examples 1 and 2) Silica-alumina (manufactured by JGC Corporation, N-
631 containing 13 wt% Al2O3) was used, and the reaction was performed in the same manner as in Example 1.

(Comparative Examples 3 and 4) Instead of the catalyst A, a stabilized Y-type zeolite (HS manufactured by Tosoh Corporation) was used as the catalyst C.
Z-330HUA) was used, and the reaction was performed in the same manner as in Example 1. The pore size of the Y-type zeolite is about 0.8 nm Al / Si atomic ratio = 1/3 The reaction conditions and results used in each example are shown in Table 1 below.

[0023]

[Table 1] AM: amine EO: ethylene oxide n-propyl:
n-Propylamine Mono: 1 mol adduct Monoethanolamine or n-propylmonoethanolamine Di: 2 mol Adduct diethanolamine or n-propyldiethanolamine Tri: 3 mol Adduct triethanolamine

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Tsuneki 14-1 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Shokubai Kawasaki Laboratory

Claims (2)

[Claims] 1. The following general formula (I) having 2 to 4 carbon atoms in the presence of a catalyst: (Wherein, R ^1, R ^2, R ³ and R ⁴ are each independently hydrogen atom, a methyl group or an ethyl group.) Alkylene oxide represented by the following general formula (II) ## STR2 ## R ⁵ —NH ₂ (II) (wherein R ⁵ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), which is reacted with ammonia or an amine represented by the following general formula (III): (In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are represented by the formulas (I) and (I
It is the same as I). ) In the method for producing an alkanolamine, the catalyst comprises Fe, C in the lattice.
A process for producing an alkanolamine, which is a crystalline metallosilicate incorporating at least one of o, Ni, B, Ga, Cr, Sc, Ti and Ge. 2. The manufacturing method according to claim 1, wherein the metal incorporated in the lattice of the crystalline metallosilicate is Fe.