JPH09136862A - Production of methylamine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound which is a chemical intermediate important as a raw material for various solvents, pharmaceuticals, rubber chemicals, surfactants, etc., by continuously using a zeolite catalyst over a long period while suppressing the lowering of the catalytic activity. SOLUTION: The objective methylamine is produced by contacting methanol and ammonia, a methanol-methylamine mixture and ammonia or methylamine mixture and ammonia with a zeolite catalyst layer. Preferably at least two zeolite catalyst layers are arranged in series and the reaction is carried out while keeping the temperature difference between the inlet and the outlet of each zeolite catalyst layer within the range of 5-70 deg.C. The zeolite catalyst is e.g. mordenite, chabazite or levynite.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing methylamine by a gas phase catalytic reaction of methanol and ammonia. More specifically, the present invention relates to a process for producing methylamine, which enables more effective utilization of the high dimethylamine selectivity characteristic of zeolite catalysts when producing methylamines using zeolite as a catalyst. Dimethylamine is an important chemical intermediate as a raw material for various solvents, pharmaceuticals, rubber chemicals, surfactants and the like.

[0002]

2. Description of the Related Art Generally, dimethylamine is obtained by reacting methanol and ammonia in the vapor phase at a high temperature (around 400 ° C.) in the presence of a solid acid catalyst such as alumina, silica-alumina having a dehydration and amination action. Is manufactured by. Usually, in this reaction, in addition to dimethylamine (hereinafter referred to as DMA), monomethylamine (hereinafter referred to as MMA) and trimethylamine (hereinafter referred to as TM).
A) is a by-product. Since the demand for these by-produced methylamines is significantly lower than that of DMA, they are recycled to the reaction system for reuse after separating dimethylamine from the reaction product.

Distillation is commonly used to separate dimethylamine from the produced methylamine. However, TMA
Since a complicated azeotropic system is formed with ammonia, MMA, and DMA, a very complicated distillation operation and a large-scale apparatus are required to separate this, and the energy consumption cost of the DMA recovery process is very large. Becomes An example of this recovery process is shown in detail, for example, in "Completed Revision of Manufacturing Process Drawing" (published on April 25, 1978 by Kagaku Kogyo Co., Ltd.).

In order to reduce the manufacturing cost of DMA and downsize the apparatus, by-product methylamine,
In particular, it is important to suppress the generation of TMA as much as possible and promote the generation of DMA. However, the selectivity of the three types of methylamine is thermodynamically determined on the above-mentioned amorphous solid acid catalyst such as alumina or silica-alumina, and the production rate of TMA greatly exceeds that of DMA under normal reaction conditions. For example, when the reaction temperature is 400 ° C. and the ratio of ammonia and methanol at the reactor inlet is 1: 1 (weight ratio), the equilibrium production ratio of each amine calculated thermodynamically is MMA: DMA: weight ratio.
TMA = 0.284: 0.280: 0.436.
In this case, the DMA selectivity defined by Equation 1 below is 2
It is only 8.4%.

[0005]

(Equation 1) (W _M , W _D , and W _T are MMA and DM, respectively.
A, the weight production ratio of TMA, M _MW , D _MW and T _MW represent the molecular weights of MMA, DMA and TMA, respectively)

Since the selectivity of DMA is insufficient, it is necessary to always separate a large amount of MMA and TMA from the reaction system and to allow the reaction to proceed equilibrium favorably to DMA in a large amount. Must be recycled to the reaction system along with excess ammonia.

In recent years, various zeolite catalysts have been proposed to solve this problem. For example, zeolite A
Japanese Patent Application Laid-Open No. 56-69846, Japanese Patent Application Laid-Open No. 54-148708, and Japanese Patent Application Laid-Open No. 58-69846.
U.S. Pat. No. 4,082,805 regarding ZSM-5, ZSM-11 and ZSM-21, JP-A-56-113747 regarding ferrierite and erionite,
JP-A 61-178951 and JP-A 63-8358 relating to zeolite rho, ZK-5 and chabazite
JP-A-61-254256, which relates to a catalyst in which DMA selectivity is further improved by treating a specific zeolite with a chemical such as tetraethyl orthosilicate.
Japanese Patent Application Laid-Open No. 7-1999 relating to mordenite modified with silylating agent
No. 2740, D by modifying by various methods
Japanese Patent Application Laid-Open No. Sho 56-56 relates to mordenite having improved MA selectivity.
-46846, JP-A-59-21050, JP-A-58-49340, JP-A-6-9510, and the like, zeolite X, Y, L, levinite, analsite, chabazite, gmelinite, erionite, putilolite,
US related to ferrierite, clinoptyllite, etc.
There are catalysts described in respective publications such as P3,384,667.

[0008] With such a zeolite catalyst, unlike the usual amorphous catalyst such as silica-alumina, it seems that all of them have a DMA selectivity higher than the thermodynamic equilibrium value. For example, Japanese Patent Application Laid-Open No. 59-21050 discloses a method for selectively producing DMA using mordenite. For example, a mordenite catalyst having various cation compositions is used, and an equal weight mixture of ammonia and methanol is mixed with 270. About 50 to about 6 by reacting at a reaction temperature of ~ 360 ° C.
A DMA selectivity of 0% is obtained. This is a value of about 2.0 to about 3.0 when converted into the DMA equilibrium magnification defined by the following Equation 2.

[0009]

(Equation 2)

Almost all of the above-mentioned zeolite catalysts have a DMA equilibrium ratio of 1.2 to 4.0, and most of them have a DMA equilibrium ratio of 1.5 to 3.5. When such a zeolite catalyst having a high DMA selectivity is used in the continuous production process of methylamines, the catalyst DMA
Increased DMA concentration in the reactor outlet gas due to the high selectivity, resulting in a reduction in the amount of recycled material from the recovery process to the reactor and a reduction in the total amount of material sent from the reactor to the recovery process. Is possible. This effect is expressed by comparing the unit process flow rates defined in Equation 3 below.

[0011]

(Equation 3)

The unit process flow rate can be adjusted by increasing / decreasing the amount of the substance recycled from the recovery system to the reactor, especially ammonia. The degree of ammonia recycling depends on the atomic ratio of N / C (nitrogen). (The ratio of the number of atoms to the number of carbon atoms), that is, the atomic ratio of N and C in the total amount of substances sent from the reactor to the recovery process. In order to reduce the load of the recovery process, it is necessary to reduce the unit process flow rate as much as possible, that is, to reduce N / C, but
It is not preferable to greatly reduce N / C because of problems such as by-product impurities.

The above-mentioned feature of the zeolite catalyst is that the unit process flow rate can be reduced without significantly decreasing N / C as compared with the conventional thermodynamic equilibrium regulation type catalyst. From this viewpoint, N / C is usually 1.0 or more, preferably 1.3 or more. For example, N /
At C = 2.0, using zeolite catalysts having different DMA equilibrium ratios, MMA, DMA, and TMA were each about 25 m long.
The unit process flow rates for manufacturing ol / hr, 65 mol / hr, and 10 mol / hr are as follows. Catalyst DMA equilibrium ratio Unit process flow rate ───────────────────────────────── Silica alumina (conventional type) 1.0 18 Zeolite (1) 1.5 13 Zeolite (2) 2.2 10 In this case, it is necessary to lower the unit process flow rate as much as possible from the above value (that is, “18”) which is the most usual case of the conventional catalyst. It becomes an important meaning to utilize the catalyst. However, such a zeolite catalyst is packed in an adiabatic reactor similar to the conventional catalyst,
When the reaction was started at the lowest possible temperature (for example, catalyst layer inlet temperature: 250 ° C. to 260 ° C.) in order to prevent the formation of coke substances, a rapid decrease in catalytic activity occurred as shown in Comparative Examples below. It turned out to be a very big problem in practical use. The decrease in catalytic activity is represented by the deterioration constant (ρ) according to the definitions of the following equations 4 and 5.

[0014]

[Formula 4] k _t = k ₀ · exp (−ρt) (4) In the formula, ρ: deterioration constant k _t : reaction rate constant after t days have elapsed k ₀ : reaction rate constant at the start of reaction

[0015]

(Equation 5) In the formula, F: methanol supply rate R: gas constant T: reaction temperature P ₀ : initial methanol partial pressure V: catalyst volume x: methanol conversion rate

When a fixed bed reactor is used as in the present process, the catalyst is commercially available for at least one year, preferably 2
It is necessary to be able to use continuously for more than a year. If the initial catalytic activity is high enough within a commercially reasonable range, it can be used until the catalytic activity drops to about one half of the initial value. In this case, the deterioration constant corresponding to the catalyst life of one year is used. Is about 0.0021. However, when a zeolite catalyst is used in a conventional reactor, the deterioration constant value is 10 times or more the above-mentioned limit value regardless of which zeolite catalyst is used, as shown in the comparative example described below. Therefore, commercial continuous use of such catalysts becomes extremely difficult.

[0017]

As described above, it is important in the technical field of the present invention to develop a method for producing methylamine capable of continuously using a zeolite catalyst for a long period of time in order to prevent the formation of a coke substance during the reaction. Has become a problem.

It is an object of the present invention to provide a method for producing methylamine which suppresses the activity reduction of the zeolite catalyst in the methylamine production process and enables the continuous use of the zeolite catalyst for a long period of time. .

[0019]

The present invention achieves the above object and comprises at least two zeolite catalyst layers.
It is based on the discovery of the fact that the catalyst life can be significantly improved by providing two catalysts in series and maintaining the temperature difference between the inlet and the outlet in each catalyst layer during the reaction within a specific range. .

That is, the method for producing methylamine according to the present invention is a method for producing methylamine which comprises contacting a zeolite catalyst layer with methanol and ammonia, a mixture of methanol and methylamine and ammonia, or a mixture of methylamine and ammonia. Therefore, at least two zeolite catalyst layers are provided in series (however, the plurality of zeolite catalyst layers provided in series are formed of different kinds of zeolite catalysts even if they are formed of the same kind of zeolite catalyst). And the temperature difference between the inlet and the outlet of each zeolite catalyst layer is maintained within the range of 5 to 70 ° C., respectively, to carry out the reaction.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

[General Description] The method for producing methylamine according to the present invention is
Basically, it consists of bringing methanol and ammonia, methanol and methylamine mixture and ammonia, or methylamine mixture and ammonia into contact with the zeolite catalyst layer. This type of methylamine production method is well known, and is essentially the same as the conventional method, except that the present invention employs the configuration specified in the present application. Therefore, the present invention includes a method provided with any modification or addition that has been conventionally adopted unless it goes against the gist of the present invention. In the production of methylamine, a methylamine mixture (MMA, DMA, TMA and other mixtures) produced from methanol and ammonia as raw materials is once taken out of the reaction system and subjected to purification treatment, and then the unreacted raw material, It has been practiced to introduce a purified product such as by-product methylamine into the reaction system again. The method for producing methylamine according to the present invention includes such an embodiment. That is, a mixture of methanol and ammonia, a mixture of methanol and methylamine and ammonia, or a mixture of methylamine and ammonia is introduced into a reaction system consisting of bringing them into contact with a zeolite catalyst layer, and at least a part of the product is introduced into the reaction system. After extracting it outside, circulating it in the purification system and subjecting it to the purification treatment,
It also relates to the introduction of this purified product into the reaction system again with the rest of the product, which should be present.

[Zeolite Catalyst Layer] As the zeolite catalyst used in the method for producing methylamine according to the present invention, any purposeful one can be used. In the present invention, the preferred zeolite catalyst layer has a dimethylamine (DMA) selectivity of 1.2 times or more of the thermodynamic equilibrium value compared to the use temperature of the zeolite catalyst, particularly 1.
Those formed from 5 times or more of the zeolite catalyst are preferable. Specific examples of particularly preferable ones among such zeolite catalysts include mordenite, chabazite, levinite, zeolite rho, zeolite A, FU-
1, erionite, ZSM-5, ZSM-11, ZSM
-21, ZK-5 or montmorillonite, or a zeolite modified based on these, or the like. Particularly preferred among these are mordenite, chabazite or modified mordenite.

In the present invention, at least two zeolite catalyst layers as described above are provided in series. Here, the plurality of zeolite catalyst layers provided in series do not necessarily have to be formed of the same kind of zeolite catalyst, and may be formed of different kinds of zeolite catalysts. Also, the dimethylamine selectivity of the zeolite catalyst layer may be different between the zeolite catalyst layers. Therefore, the total number of zeolite catalyst layers provided in series is 2 or more. From the viewpoint of the effect of the present invention, equipment cost, operability, etc.,
-10, preferably 2-7, especially 3-5 are preferred.

The reaction in each zeolite catalyst layer is different from the difference in methanol conversion rate between each zeolite catalyst layer based on the first zeolite catalyst layer inlet (exit-inlet).
Is preferably 10 to 60%, particularly preferably 15 to 5
Perform within the range of 0%. If it is less than 10%, the total number of zeolite catalyst layers will be large and the apparatus will be complicated, while if it exceeds 60%, the catalyst life will tend to be shortened.

The N / C (ratio of the number of nitrogen atoms and the number of carbon atoms) in the zeolite catalyst layer is preferably 0.8-3.
0, more preferably 1.0 to 2.5, and particularly preferably 1.2 to 2.2. If the atomic ratio of N / C is less than the above range, the amount of by-products tends to increase, while if it exceeds 3.0, the amount of recycling tends to increase and the device tends to increase in size.

[Temperature Control] In the present invention, the temperature difference between the inlet and the outlet of each zeolite catalyst layer is maintained within the range of 5 to 70 ° C., preferably 20 to 60 ° C., and particularly preferably 25 to 45 ° C. While reacting. When the temperature difference exceeds 70 ° C, the catalyst life tends to be shortened, while when it is less than 5 ° C, it is difficult to obtain a desired methanol conversion rate. As a method for controlling the temperature difference between the inlet and the outlet of the zeolite catalyst layer within the above range, any purposeful method can be adopted. For example, (a) control of the flow rate, flow rate, composition or temperature of the gas supplied to the zeolite catalyst layer, (b) control of the type and amount of the zeolite catalyst, contact area, (c) the inlet and outlet of the zeolite catalyst layer. Setting of distance, (d) Temperature control from outside the zeolite catalyst layer (including cooling and heating),
(E) There is other

From the viewpoint of preventing the formation of impurities such as coke, it is desirable that the inlet temperature of each catalyst layer be close to the lowest temperature at which the reaction starts at a purposeful rate, and usually 200 to
It is preferable to adjust the temperature to 350 ° C., preferably 220 to 330 ° C., and particularly preferably 230 to 310 ° C.

As a method for controlling the inlet temperature of the catalyst layer within the above range, any purposeful method can be adopted. One of the preferable methods in the present invention is to control the temperature of the feed to the catalyst layer within a predetermined range (including heating and cooling).
Since the feed to the first (first) zeolite catalyst layer is mainly composed of the raw material methanol newly introduced into the reaction system, the raw material ammonia, and the methylamine subjected to the purification treatment, Since it is often lower than the temperature range, heating is usually performed, while the feed to the second and subsequent catalyst layers may be higher than the above temperature range due to the heat of reaction in the preceding catalyst layer. Since it is many, cooling is usually performed in that case. The heating of the feed to the first zeolite catalyst layer depends on the reaction system and / or
The heat of the refining system can be used, while the temperature control of the feed to the second and subsequent catalyst layers is performed by heat exchange with a cooling medium, preferably air, nitrogen gas, steam, etc. Can be done by Further, as another method of controlling the inlet temperature of the second and subsequent zeolite catalyst layers, the feed gas to the catalyst layer is introduced with at least a part of the refined product from the refining system, or the raw material methanol or the raw material ammonia. There is a way to adjust by doing.

[Specific Example] A preferred specific example of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of the present invention, and the present invention is not limited to this. The raw materials methanol and ammonia (line) are combined with a recycled product (line; gas and / or liquid) mainly consisting of ammonia, MMA and TMA from the purification step (P), and subjected to operations such as evaporation and heating, It is supplied in a gaseous state (line) to the first section (S1) of the zeolite catalyst layer at a predetermined temperature. In this first section (S1), the raw materials and recycled products react, and the outlet gas (line-1) is the second section (S2) of the zeolite catalyst layer, and then the outlet gas (line-2) is the next section. It is sequentially supplied to (S3). Unreacted raw materials and recycled materials in the outlet gas react in each section.

As described above, the reaction is carried out while maintaining the temperature difference between the inlet and the outlet of each zeolite catalyst layer within the range of 5 to 70 ° C. The inlet temperature of each catalyst layer is usually adjusted to a range of 200 to 350 ° C.

The outlet gas of each catalyst layer is preferably temperature-controlled and then supplied to the next catalyst layer. This makes it easy to adjust the catalyst layer inlet temperature and maintain the temperature in the catalyst layer. The temperature control of the outlet gas is air,
It can be performed by a cooler or a heat exchanger using a medium such as nitrogen gas or steam, and a part (Q1, Q2) of the recycled product and / or a part (Q3) of the raw material can be directly used as the outlet gas. It can also be supplied. The latter control is particularly effective in terms of heat recovery and equipment cost reduction.

The exit gas (line) of the last section (S3) is heat-exchanged with the raw material supply line and then sent to the refining step (P). In the purification step (P), the methylamines are separated and recovered from the unreacted ammonia and the reaction product water by the plurality of distillation columns, and the unreacted ammonia and MMA are separated.
And TMA are returned to the reaction system as recycled products (lines).

The number of catalyst layers is preferably 2-10. Further, in the reaction in each catalyst layer, it is preferable that the difference (outlet-inlet) in the methanol conversion rate based on the first catalyst layer inlet in each catalyst layer is within the range of 10 to 60%.

N / C (ratio of the number of nitrogen atoms and carbon atoms) in the zeolite catalyst layer is preferably in the range of 0.8 to 3.0. The reaction pressure is usually from normal pressure to 200.
It is performed in the range of atm.

[0035]

The following examples serve to explain the present invention more specifically. Therefore, it goes without saying that the present invention is not limited to the specific disclosure scope of the following examples.

[Catalyst to be used] Z1 ... H-type mordenite steamed at 300 ° C. for 30 hours (diameter of about 5 mm) Z2 ... Cationic mordenite containing 0.7% by weight of K and Ca (diameter) A mixture of chabazite and erionite (diameter: about 5 mm) A: Amorphous silica alumina with a silica content of about 70% (diameter: about 5 mm)

Examples 1-5 Three adiabatic reactors (total volume of about 20
m ³ ), each of which is filled with a zeolite catalyst to cool the gas between each catalyst layer (S 1, S 2 and S 3) section,
Between S1 and S2 are recycled materials (liquid and gas), and between S2 and
During S3, recycled materials (liquid and gas) and air cooling were used together. Raw material methanol and raw material ammonia are supplied to S1 at 161 kgmol and 87 kgmol per hour, respectively, and MMA, DMA, and TMA are supplied at 20 kgmo per hour.
The continuous reaction (2 weeks to 1 month) was carried out so that it was produced at 1, 60 kgmol, and 7 kgmol. From the change in the methanol conversion rate in this case, the catalyst deterioration constants shown in Table 1 were obtained according to the above equations 4 and 5. The number of catalyst layers is 2 when the gas cooling between the catalyst layer sections is performed at one location, and is 3 when the gas cooling is performed at two locations.

Examples 6 to 8 Continuous reaction tests (2 weeks to 1 month) were performed by using a plurality of reaction tubes having a diameter of about 1 inch connected in series as shown in FIG. 2 and cooling between the reaction tubes. did. Since this device does not have a recovery process and a recycling process, assuming the case where recovery and recycling were performed in each case in advance, the following composition was prepared and used as a raw material.
Further, in order to make the heat radiation per unit amount of gas of the present apparatus equal to that of the reactor shown in FIG. 1, the surface of the reactor was heated and kept warm. The similarity of both devices was confirmed by Examples 3 and 6. Raw material composition (mol%) Ammonia Methanol MMA TMA Examples 6 to 7 60 30 8 2 Example 8 59 31 7 3 [Results] Table 1 collectively shows the results of Examples 1 to 8 above.

[0039]

[Table 1]

Comparative Examples 1 and 2 A silica-alumina catalyst (A) was charged in an adiabatic reactor having a volume of about 10 m ³ shown in FIG. 3, methanol and ammonia were supplied at 120 kgmol and 65 kgmol per hour, respectively, and M
MA, DMA, and TMA are 15 kgmol and 45 hourly, respectively.
A continuous reaction was carried out at a production rate of 5 kgmol. The catalyst deterioration constants in this case are shown in Table 2.

Comparative Examples 3 to 4 A zeolite catalyst (Z1) was packed in an adiabatic reactor having a volume of about 20 m ³ shown in FIG. 1 and methanol and ammonia were added without cooling the gas between the catalyst bed sections at all. Supplying 161 kgmol and 87 kgmol per hour respectively, M
MA, DMA and TMA are 20 kgmol and 60 hourly, respectively.
A continuous reaction was carried out at a production rate of kgmol and 7 kgmol. The catalyst deterioration constants in this case are shown in Table 2. In this case, since the gas cooling between the catalyst layer sections was not performed, the same adiabatic reactor as in Comparative Example 1 was used.

Comparative Examples 5 to 7 Continuous reaction tests were conducted using a plurality of reaction tubes having a diameter of about 1 inch connected in series as shown in FIG. 2 without cooling between the reaction tubes. Since this device does not have a recovery process and a recycling process, assuming the case where recovery and recycling were performed in each case in advance, the following composition was prepared and used as a raw material. Further, in order to make the heat radiation per unit amount of gas of the present apparatus equal to that of the reactor shown in FIG. 3, the surface of the reactor was heated and kept warm. The similarity of both devices was confirmed by Comparative Examples 4 and 5. In this case, since the gas cooling between the catalyst layer sections was not performed, the same adiabatic reactor as in Comparative Example 1 was used. Raw material composition (mol%) Ammonia Methanol MMA TMA Comparative Examples 5 to 7 60 30 8 2 [Results] Table 2 collectively shows the results of the above Comparative Examples 1 to 7.

[0043]

[Table 2]

[Discussion] Comparative Examples 1 and 2 are examples in which a conventional adiabatic reactor is used to carry out the reaction using silica alumina, which is a conventional thermodynamic equilibrium regulation type catalyst. The deterioration constant of the catalyst in this case is 0.8, and the catalyst life is equivalent to 2 years or more. Comparative Examples 3 to 7 are examples in which a similar device was used to carry out the reaction using various zeolite catalysts. The catalyst layer inlet temperature is 250 ° C. to 2 ° C., which is close to the minimum temperature at which the reaction starts at a reasonable rate in order to prevent side reactions such as coke formation.
Despite keeping the temperature as low as possible at 60 ℃,
The deterioration constant was an extremely large number of 17 to 24. This indicates that the catalyst life is only 1 to 2 months, which is a very unsatisfactory result for practical use. In general, since the pores of the zeolite catalyst are extremely smaller than those of the amorphous catalyst, its activity is likely to be affected by the coke substance deposited on the catalyst surface, and it is considered that this is because of this.

On the other hand, in Examples 1 to 8, according to the method of the present invention, the catalyst layer of zeolite was divided into 2 to 4 in series, and the temperature difference between the inlet and the outlet of each catalyst layer was 25.
This is an example in which the reaction was carried out under the same conditions as in the comparative example except that the operation was added to maintain the reaction within the range of 60 ° C to 60 ° C. As a result, surprisingly, the deterioration constant of the catalyst is 7 to
It dropped to 11. This corresponds to a catalyst life of 1 to 2 years or more, and it is recognized that the length is dramatically improved to a length that can be sufficiently used in industrial practice.

[0046]

EFFECTS OF THE INVENTION According to the method of the present invention, the catalyst life in the process for producing methylamines using a zeolite catalyst can be significantly improved, and the catalyst can be used for a long time in a reaction at a low reaction temperature below. Can be used continuously. Thereby, the production of methylamines can be carried out industrially advantageously.

[Brief description of the drawings]

FIG. 1 is a schematic flow sheet of one of the apparatuses for carrying out the method for producing methylamine according to the present invention.

FIG. 2 is another schematic flow sheet of an apparatus for carrying out the method for producing methylamine according to the present invention.

FIG. 3 is a schematic flow sheet of a conventional methylamine manufacturing apparatus.

[Explanation of symbols]

 S: Catalyst layer S1: First catalyst layer S2: Second catalyst layer S3: Third catalyst layer S4: Fourth catalyst layer P: Purification step C: Cooler C1: First catalyst layer outlet gas cooler C2: Second Catalyst layer outlet gas cooler: Raw material: Reactor supply gas -1: Second catalyst layer supply gas -2: Third catalyst layer supply gas -3: Fourth catalyst layer supply gas: Reaction product gas: Recycled product: Product: Product: Product: Out-of-system emission Q1: Branch recycled product for gas cooling at the outlet of the first catalyst layer Q2: Branch recycled product for cooling gas at the outlet of the second catalyst layer Q3: Raw material for cooling gas at the catalyst layer outlet

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // C07B 61/00 300 C07B 61/00 300

Claims (10)

[Claims] 1. A process for producing methylamine, which comprises contacting a zeolite catalyst layer with methanol and ammonia, a mixture of methanol and methylamine and ammonia, or a mixture of methylamine and ammonia with at least 2 zeolite catalyst layers. Provided in series (however, the plurality of zeolite catalyst layers provided in series may be formed of the same kind of zeolite catalyst or different kinds of zeolite catalyst), and The temperature difference between the inlet and the outlet of each zeolite catalyst layer is 5 to 70 ° C.
The method for producing methylamine, characterized in that the reaction is carried out while each is maintained within the range. 2. Methanol and ammonia, a mixture of methanol and methylamine and ammonia, or a mixture of methylamine and ammonia are introduced into a reaction system comprising contacting these with a zeolite catalyst layer, and at least a part of the product is introduced. Is extracted from the reaction system, circulated in the purification system and subjected to a purification treatment, and then this purified product is reintroduced into the reaction system together with the rest of the product which may be present. A method for producing methylamine, wherein at least two zeolite catalyst layers are provided in series (provided that the plurality of zeolite catalyst layers provided in series are different even if they are formed from the same type of zeolite catalyst). And the temperature difference between the inlet and the outlet of each zeolite catalyst layer is 5 to 70 ° C. A method for producing methylamine, characterized in that the reaction is carried out while maintaining each within the range. 3. The at least one zeolite catalyst is characterized by being formed by a zeolite catalyst having a dimethylamine selectivity of 1.2 times or more a thermodynamic equilibrium value as compared with the operating temperature of the zeolite catalyst. The method for producing methylamine according to claim 1 or 2. 4. The zeolite catalyst is mordenite, chabazite, levinite, zeolite rho, zeolite A, FU-1, erionite, ZSM-5, ZSM-1.
1, ZSM-21, ZK-5 or montmorillonite,
Alternatively, the method for producing methylamine according to any one of claims 1 to 3, which is selected from zeolites modified based on these. 5. The total number of zeolite catalyst layers is 2-1.
It is 0, The manufacturing method of the methylamine of any one of Claims 1-4 characterized by the above-mentioned. 6. The method for producing methylamine according to claim 1, wherein the temperature of the inlet of the at least one zeolite catalyst layer is in the range of 200 to 350 ° C. 7. The method for producing methylamine according to claim 1, wherein the gas supplied from one zeolite catalyst layer to the next zeolite catalyst layer is cooled. 8. The gas supplied from one zeolite catalyst layer to the next zeolite catalyst layer is cooled by introducing at least a part of a refined product from the refining system, raw material ammonia, or raw material methanol. The method for producing methylamine according to claim 2. 9. The N / C (ratio of the number of nitrogen atoms and the number of carbon atoms) in at least one zeolite catalyst layer is 0.8.
It is the range of -3.0, The manufacturing method of the methylamine of any one of Claims 1-8 characterized by the above-mentioned. 10. The reaction in each zeolite catalyst layer comprises:
The difference (exit-inlet) in the methanol conversion rate based on the first zeolite catalyst layer inlet in each zeolite catalyst layer is 10
It is in the range of -60%.
The method for producing methylamine according to any one of 1.