JPH04342578A - Production of n-alkylated cyclic alkyleneimine - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high yield by reacting a cyclic ether with ammonia in the vapor phase in the presence of a catalyst, removing a specific compound from the resultant reaction mixture and then reacting the prepared reaction mixture wish an alcohol, etc., in the vapor phase. CONSTITUTION:A cyclic ether (preferably THF, etc.) is catalytically reacted with ammonia in the vapor phase in the presence of a solid acid catalyst (preferably faujasite type zeolite, etc.), preferably under conditions of 5-20 molar ratio of ammonia/cyclic ether, 300-380 deg.C temperature and 1-20kg/cm<2>G pressure. Components having a lower boiling point than that of a cyclic alkyleneimine are removed from the resultant cyclic alkyleneimine-containing reaction mixture and the residue is then reacted with an alcohol (preferably methanol) or ether (preferably methyl ether) in the vapor phase in the presence of a solid acid catalyst under conditions of 1-5 molar ratio of alcohol/cyclic alkyleneimine, 300-400 deg.C and 0.1-10kg/cm<2>G pressure to afford the objective compound.

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 N-alkylated products of cyclic alkyleneimines. Specifically, the present invention relates to an improvement in a method for producing an N-alkylated product of a cyclic alkyleneimine from a cyclic ether.

0002

BACKGROUND OF THE INVENTION N-alkylated products of cyclic alkyleneimines are useful substances as intermediates for the production of pharmaceuticals, insecticides, rubber vulcanization accelerators, and the like. Cyclic alkyleneimine N-
To obtain the alkylated product, a cyclic ether is used as a starting material, which is reacted with ammonia to give a cyclic alkylene imine, which is then converted into an alcohol
A possible method is to perform N-alkylation by reacting with alcohol or ether.

Conventionally, various methods for producing pyrrolidine from tetrahydrofuran and ammonia have been proposed as methods for producing cyclic alkylene imines from cyclic ethers, as shown below. (a) A method of reacting tetrahydrofuran and ammonia at 400°C in the presence of an alumina catalyst [Chemical Abstracts. Vo
l. 32, 548 (1938)]. (b) A method in which tetrahydrofuran and excess ammonia are reacted at 275 to 375°C in the presence of a γ-alumina catalyst (U.S. Patent No. 2,
No. 525, 584). (c) A method in which tetrahydrofuran and ammonia are reacted using a γ-alumina catalyst treated with boric acid (Japanese Patent Publication No. 19940/1983). (d)
A method of reacting tetrahydrofuran and ammonia using a zeolite catalyst [J. Catalysis, 35
, 325-329 (1974)].

On the other hand, various methods shown below are known as methods for obtaining N-alkylated products of cyclic alkyleneimines. (a) A method of reacting morpholine and alcohol at 150-300°C and 35-350 atm using a catalyst consisting of nickel or cobalt, copper and titanium dioxide (Belgium Patent No. 694068), (b )
A method of reacting piperazine and alcohol at 200°C using a Raney-nickel catalyst [J. Org. Chem
, 21, 86-87 (1956)], (c) A method of reacting piperidine and alcohol using an aluminum oxide catalyst [Coll. of Czechoslova
k Chemical Communications
, Vol. 33, No. 2, 609-613 (1968)
], (d) A method of reacting a cyclic alkylimine such as morpholine, piperazine, piperidine, etc. with an alcohol in the presence of a silicon dioxide catalyst containing phosphoric acid (Japanese Patent Laid-Open No. 48
(e) cyclic alkylene imine and alcohol or ether using faujasite type zeolite in which cation sites are exchanged with hydrogen ions, ammonium ions or polyvalent metal ions, and A method of reacting in a gas phase (JP-A-2-62869).

[0005]

[Problems to be Solved by the Invention] However, in the reaction of producing a cyclic alkylene imine by reacting a cyclic ether and ammonia in the gas phase in the presence of a solid acid catalyst, thermal decomposition, condensation, polymerization, etc. Various side reactions are likely to occur, and as a result, large amounts of by-products such as hydrocarbon decomposition products and high-boiling cyclic alkylene imine condensates are produced, making it difficult to obtain cyclic alkylene imines in good yields. Can not. Therefore, when producing an N-alkylated product of a cyclic alkylene imine by N-alkylating this cyclic alkylene imine, the consistent yield from the cyclic ether as a starting material was extremely low. The object of the present invention is to solve the above-mentioned problems caused by conventional methods and to produce N-alkylated products of cyclic alkyleneimines from cyclic ethers in excellent consistent yields.

[0006]

[Means for Solving the Problems] As a result of repeated studies to achieve the above object, the present inventors separated a cyclic alkylene imine from a reaction mixture obtained by reacting a cyclic ether with ammonia. The present invention was achieved by confirming that an N-alkylated product of a cyclic alkyleneimine can be efficiently obtained when a specific component in a mixture is removed and then subjected to an N-alkylation treatment. That is, the gist of the present invention is (a) a first step of reacting a cyclic ether and ammonia in the gas phase in the presence of a solid acid catalyst to obtain a reaction mixture containing a cyclic alkyleneimine; ) From the reaction mixture obtained in the first step, the residue obtained by removing at least a part of the components with a lower boiling point than the cyclic alkylene imine is heated in the gas phase in the presence of alcohol or ether and a solid acid catalyst. A second step of obtaining an N-alkylated product of a cyclic alkylene imine by reacting the N-
It consists in a method for producing an alkylated product.

The present invention will be explained in detail below. (a) First step: Production of cyclic alkylene imine In the first step, a cyclic ether and ammonia are reacted in the gas phase in the presence of a solid acid catalyst to produce a cyclic alkylene imine. Various cyclic ethers are used as raw material, but usually the following formula (1)

[Chemical formula 1] (In the formula, R has 2 to 2 carbon atoms, which may be substituted with an alkyl group, an alkylene group, an aryl group, or an alkoxy group.
12 polymethylene groups; or a polymethylene heterochain group having 2 to 10 carbon atoms and having 1 to 2 nitrogen atoms, oxygen atoms, or sulfur atoms in the chain).

Specifically, for example, propylene oxide,
Examples include tetrahydrofuran, tetrahydropyran, cyclohexene oxide, styrene oxide, dioxane, and morpholine, with tetrahydrofuran and tetrahydropyran being preferred. Examples of the solid acid catalyst used in the first step include silica-alumina, alumina, zeolite, silica-magnesium oxide, silica-zirconium oxide, and especially silica-alumina,
Alumina and zeolite are preferred. As the zeolite, faujasite-type zeolite and chabasite-type zeolite, in which at least a portion of the cation sites are ion-exchanged with hydrogen, ammonium, or polyvalent metal cations, are preferably used.

The reaction in the first step is carried out by bringing the above-mentioned cyclic ether and ammonia into contact in the gas phase in the presence of a solid acid catalyst. Reaction temperature is usually 250-400℃
, preferably from the range of 300 to 380°C. The reaction is carried out under atmospheric pressure to increased pressure, preferably 0.
5 to 50 kg/cm2G, particularly preferably 1 to 20 kg
/cm2G. Further, the ammonia/cyclic ether molar ratio is generally in the range of 1 to 50, preferably 2 to 30, and more preferably 5 to 20. The gas phase catalytic reaction can be carried out in a general manner such as a fixed bed format or a fluidized bed format. Space velocity [total gas amount of cyclic ether and ammonia in standard state (1000 ml/hr)/
The amount of catalyst (1000 ml) can be varied over a wide range depending on conditions such as reaction temperature and ammonia/cyclic ether molar ratio, but it is usually 50 to 4000 hr-1,
Preferably space velocities in the range 100 to 3000 hr-1 are employed.

In the reaction mixture obtained in the first step, in addition to the product cyclic alkylene imine, unreacted raw materials such as ammonia and cyclic ether and by-products such as cyclic alkylene imine such as hydrocarbons are present. It contains components with a lower boiling point than the imine, and further contains by-products and the like with a higher boiling point than the cyclic alkylene imine. The features of the present invention are as follows:
Without separating and purifying the cyclic alkylene imine from the reaction mixture, only the components with a lower boiling point than the cyclic alkylene imine contained in the reaction mixture are removed, and the mixture containing the cyclic alkylene imine and the higher boiling point component is purified from the subsequent cyclic alkylene imine. It is used as a raw material for the imine N-alkylation step (second step). Among the low-boiling components, it is preferable to remove a substantial amount of ammonia, particularly preferably the entire amount. It is also desirable to remove low boiling point components such as cyclic ethers and hydrocarbons as much as possible. If a large amount of unreacted raw materials and by-products having a boiling point lower than that of these cyclic alkylene imines remain, side reactions in the subsequent second step increase and the burden of purification increases.

(b) Second step: Production of N-alkylated product of cyclic alkylene imine In the second step, after removing low boiling point components from the reaction mixture obtained in the first step, the cyclic alkylene imine and the high boiling point sub-product are removed. The N-alkylated product of a cyclic alkylene imine is produced by reacting a mixture containing a living organism with an alcohol or an ether in the gas phase in the presence of a solid acid catalyst. Alcohol
Examples of the alcohol include aliphatic alcohols such as methanol, ethanol, propanol, isopropanol, and butanol; alicyclic alcohols such as cyclopentanol and cyclohexanol; Examples include aromatic alcohols such as alcohol, and among them preferred are aliphatic alcohols having 4 or less carbon atoms, and methanol is particularly preferred. Examples of ethers include ethers corresponding to the above-mentioned aliphatic alcohols, such as methyl ether, ethyl ether, propyl ether, isopropyl ether, butyl ether, etc. In particular, methyl ether is suitable.

[0012] Examples of the solid acid catalyst used in the second step include silica-alumina, alumina, zeolite,
Examples include silica-magnesium oxide and silica-zirconium oxide, with silica-alumina, alumina, and zeolite being particularly preferred. As the zeolite, faujasite type zeolite in which at least a portion of its cation sites are ion-exchanged with hydrogen, ammonium, or polyvalent metal cations is preferably used.

[0013] In the reaction of the second step, a mixture containing a cyclic alkylene imine and a high-boiling by-product obtained by removing the low-boiling by-product from the reaction mixture of the first step, and an alcohol or an ether. is carried out by contacting them in the gas phase in the presence of a solid acid catalyst. The reaction temperature is usually 200 to 400
℃, preferably selected from the range of 300 to 400℃. The reaction is carried out under atmospheric pressure to increased pressure, preferably 0.1 to
It is 10kg/cm2G. Further, the molar ratio of alcohol/cyclic alkyleneimine is generally in the range of 1 to 10, preferably 1 to 5. The molar ratio of ether/cyclic alkyleneimine is suitably half that of alcohol.

[0014] The gas phase catalytic reaction can be carried out in a general manner such as a fixed bed format or a fluidized bed format. Space velocity [
Total gas volume of cyclic alkyleneimine, high boiling substance, alcohol or ether under standard conditions (1000 ml/h
r)/catalyst amount (1000 ml)] can be varied over a wide range depending on conditions such as reaction temperature and molar ratio of alcohol or ether/cyclic alkylene imine, but is usually 50 to 4
000 hr-1, preferably 100-3000 hr
A space velocity of −1 is adopted. The N-alkylated product of the cyclic alkyleneimine produced in the second step described above can be easily separated and purified from the reaction mixture by well-known separation means such as distillation.

[0015]

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples unless the gist thereof is exceeded.

Example 1 First step: Upright reaction tube made of SUS-316 (inner diameter 25
90 cc of glass beads were filled in the upper part of the cyclic ether and ammonia evaporation pre-zone (480 mm in length), and a silica-alumina catalyst (480 mm in length) was packed in the lower part as a reaction zone.
40 g of N631HN (manufactured by JGC Chemical Co., Ltd.) was filled. The reaction tube was heated from the outside with an annular electric furnace to maintain the pre-evaporation zone and reaction zone at a predetermined temperature. Tetrahydrofuran (abbreviated as THF) and ammonia were added to the reaction zone at 593.9 mmol/hr and 4166.8 mmol/hr (ammonia/THF), respectively.
molar ratio: 7.0), reaction temperature 370°C, catalyst amount (g)/total raw material supply amount (mol/hr): 8.4
g・hr/mol, space velocity (hr-1): 1330,
The reaction was carried out under the conditions of reaction pressure: 10 kg/cm2G. The conversion rate of THF was 96.8%, and the selectivity of pyrrolidine was 92.8%.

The resulting reaction mixture was condensed and collected in a trap cooled with an ethylene glycol-water refrigerant. Next, this was distilled at 50°C under normal pressure to remove low-boiling substances (ammonia, propylene, butadiene, etc.), and the residual liquid was analyzed by gas chromatography. ), 2.5% (by weight) of by-products with a lower boiling point than pyrrolidine, 3.5% (by weight) of by-products with a higher boiling point than pyrrolidine, and 21.5% (by weight) of water.
Met. Table 1 shows the compositions of pyrrolidine, low-boiling components, high-boiling components, and water before and after distillation.

[0018]

[Table 1]

Second step: In the upper part of the same reaction tube used in the first step, 90 cc of glass beads were filled as a pre-evaporation zone for the cyclic alkylene imine and methanol, and in the lower part, an alumina catalyst (as a reaction zone) was filled. SCM-250 Low
(Manufactured by Ne Poulenc) 50g was filled. The reaction tube was heated from the outside with an annular electric furnace to maintain the pre-evaporation zone and reaction zone at a predetermined temperature. The residual liquid obtained in the first step and methanol were added to the reaction zone at a rate of 212.2% each.
It was supplied in an amount of 5 mmol/hr (the amount of pyrrolidine in the pot residue) and 276.36 mmol/hr (methanol/pyrrolidine molar ratio: 1.3), under normal pressure and at a temperature of 36 mmol/hr.
5°C, catalyst amount (g)/total raw material supply amount (mol/hr):
65.8 g・hr/mol, space velocity (hr-1):
The reaction was carried out under 189 conditions.

The resulting reaction mixture was condensed and collected in a trap cooled with an ethylene glycol-water refrigerant, and the resulting reaction product was analyzed by gas chromatography. Further, uncondensed gas components were collected in a gaseous state and analyzed by gas chromatography, and were found to be methylamines, hydrocarbons, dimethyl ether, etc. The conversion rate of pyrrolidine was 97.3%, and the yield of N-methylpyrrolidine was 93.6%. Note that the yield of N-methylpyrrolidine was calculated based on pyrrolidine in the feedstock.

Comparative Example 1 In Example 1, instead of the pyrrolidine-containing bottom liquid and methanol (methanol/pyrrolidine molar ratio: 1.3) used in the second step, a solution separated from the bottom liquid was used. Purity 79.8
Almost the same as the second step of Example 1 except that 232.12 mmol/hr of pyrrolidine and 301.24 mmol/hr of methanol (methanol/pyrrolidine molar ratio: 1.3) were used. Conditions: normal pressure, reaction temperature 360°C, catalyst amount (g)/total raw material supply amount (mol/
hr): 65.3 g・hr/mol, space velocity (hr
-1): The reaction was carried out under the conditions of 191. The conversion rate of pyrrolidine was 97.8%, and the yield of N-methylpyrrolidine was 90.0%. The yield of N-methylpyrrolidine was calculated based on the pyrrolidine in the feed.

Example 2 First step: At the top of the reaction tube used in Example 1, a cyclic acetate was placed.
Glass beads 9 as a pre-evaporation zone for ester and ammonia
0 cc, and 20 g of alumina catalyst (SCM-250 manufactured by Rhone-Poulenc) was charged as a reaction zone at the bottom.
Filled. The reaction tube was heated from the outside with an annular electric furnace to maintain the pre-evaporation zone and reaction zone at a predetermined temperature. THF and ammonia were added to the reaction zone at 29% each.
5.6 mmol/hr and 2083.4 mmol/
hr (ammonia/THF molar ratio: 7.0), reaction temperature 370°C, catalyst amount (g)/total raw material supply amount (mol/hr): 8.4 g・hr/mol, space velocity (hr-1): 1570, reaction pressure: 2 kg/cm
The reaction was carried out under 2G conditions. The conversion rate of THF is 92.
8%, and the selectivity of pyrrolidine was 69.4%.

The resulting reaction mixture was condensed and collected in a trap cooled with an ethylene glycol-water refrigerant. Next, this was distilled at 60°C under normal pressure to remove low-boiling substances, and the residual liquid in the pot was analyzed by gas chromatography, which revealed that the composition was 57.1% (by weight) of pyrrolidine, with a secondary substance having a lower boiling point than pyrrolidine. Product content: 3.0% (weight), by-product content with a higher boiling point than pyrrolidine: 18.0% (weight), and water: 21.
It was 9% (weight). Table 2 shows the compositions of pyrrolidine, low-boiling components, high-boiling components, and water before and after distillation.

[0024]

[Table 2]

Second step: The upper part of the reaction tube used in the first step was filled with 90 cc of glass beads as a preevaporation zone for the cyclic alkylene imine and methanol, and the lower part was filled with an alumina catalyst (SCM- 250 Rhone Pou
(manufactured by Ran Co., Ltd.) 20g was filled. The reaction tube was heated from the outside with an annular electric furnace to maintain the pre-evaporation zone and reaction zone at a predetermined temperature. The pot residue obtained in the first step and methanol were each added to the reaction zone at a rate of 64.46 mmol/
hr (amount of pyrrolidine in the pot residue) and 94.62 m
mol/hr (methanol/pyrrolidine molar ratio: 1.
5), under normal pressure, at a temperature of 365°C, and in an amount of catalyst (g
)/total raw material supply amount (mol/hr): 73.8 g・h
The reaction was carried out under the conditions of r/mol and space velocity (hr-1): 179.

The resulting reaction mixture was condensed and collected in a trap cooled with an ethylene glycol-water refrigerant, and the resulting reaction product was analyzed by gas chromatography. Further, uncondensed gas components were collected in a gaseous state and analyzed by gas chromatography, and were found to be methylamines, hydrocarbons, dimethyl ether, etc. . The conversion rate of pyrrolidine was 98.7%, and the yield of N-methylpyrrolidine was 106.2%. Note that the yield of N-methylpyrrolidine was calculated based on pyrrolidine in the feedstock.

Comparative Example 2 In Example 2, instead of the pyrrolidine-containing bottom liquid and methanol (methanol/pyrrolidine molar ratio: 1.5) used in the second step, a solution separated from the bottom liquid was used. Purity 79.8
Weight% of pyrrolidine 85.52 mmol/hr and methanol 858.52 mmol/hr (methanol/
The conditions were the same as in the second step of Example 2, except that pyrrolidine molar ratio: 1.5) was used, i.e., under normal pressure, reaction temperature 3.
60°C, catalyst amount (g)/total raw material supply amount (mol/hr)
:66.7g・hr/mol, space velocity (hr-1):
The reaction was carried out under 186 conditions. The conversion rate of pyrrolidine is 9
9.6%, and the yield of N-methylpyrrolidine was 8.
It was 6.3%. Note that the yield of N-methylpyrrolidine was calculated based on pyrrolidine in the feedstock.

[0028]

According to the present invention, only components with lower boiling points than the cyclic alkylene imine in the reaction mixture are removed without separating and purifying the cyclic alkylene imine from the reaction mixture obtained by reacting cyclic ether and ammonia. However, by immediately following the N-alkylation treatment, it is possible to not only produce an N-alkylated product of a cyclic alkylene imine from the cyclic ether in high yield, but also to reduce the load required for separation and purification of the cyclic alkylene imine. Since the cost can be saved, it greatly contributes to the industrial production of N-alkylated products of cyclic alkyleneimines.

Claims (1)

[Claims] Claim 1: (a) a first step of obtaining a reaction mixture containing a cyclic alkylene imine by reacting a cyclic ether and ammonia in the presence of a solid acid catalyst in a gas phase; Reacting the residue obtained by removing at least part of the components with a lower boiling point than the cyclic alkylene imine from the reaction mixture obtained in the step with alcohol or ether in the presence of a solid acid catalyst in the gas phase. 2. A method for producing an N-alkylated product of a cyclic alkylene imine, the method comprising: a second step of obtaining an N-alkylated product of a cyclic alkylene imine.