JPH0458462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for catalytic hydrogenation of furfurylamine (hereinafter sometimes abbreviated as FAM) and/or tetrahydrofurfurylamine (hereinafter sometimes abbreviated as 4HFAM).

According to the method of the invention, from furfurylamine and/or tetrahydrofurfurylamine
- The reaction conditions for producing aminopentanol and piperidine can be optimized, and these useful target products can be efficiently produced.

5-Aminopentanol is a difunctional compound and is useful as a raw material for various resins, a resin additive, and as an intermediate for pharmaceuticals, agricultural chemicals, rubber chemicals, and the like. Piperidine is also a compound useful as a raw material for medicines, agricultural chemicals, rubber chemicals, and the like. Therefore, techniques for industrially producing these compounds at low cost are of great interest.

A well-known method for producing piperidine is to hydrogenate piperidine, but since pyridine is relatively expensive, many production methods using raw materials other than pyridine have been proposed. for example,
Deammoniated cyclization reaction of 1,5-pentanediamine, tetrahydropyran, 1,5-
There are methods using ammonolysis reaction of pentanediol or tetrahydrofurfuryl alcohol, respectively, and methods using hydrogenation reaction of FAM or 4HFAM, but these methods are difficult to obtain raw materials, require high temperatures, and have low yields. Alternatively, none of these methods can be used as an industrial method because the process is complicated and uneconomical.

Among these methods, FAM or 4HFAM hydrogenation reaction method involves reductive ammonolysis from furfural, which is produced in large quantities from agricultural products, and 4HFAM can be obtained by hydrogenation of FAM, both of which can be obtained in high yield. Therefore, if a method for obtaining piperidine in high yield using these raw materials could be established, it would be an excellent industrial production method.

According to US Pat. No. 2,265,201, piperidine is "favorably produced" through a batch hydrogenation reaction at 250°C and 200 atm for 10 hours by adding liquid ammonia to FAM and using a cobalt catalyst weighing one-tenth of the weight of the raw materials. It is said that it can be obtained with "yield" (values are not stated). It is said that piperidine can be obtained in ``good yield'' using 4HFAM in the same manner as with FAM, except that carbon monoxide is added. Furthermore, it is said that piperidine can be obtained in a "good yield" using a copper chromite catalyst or a nickel catalyst in a system in which ammonia is added under conditions of high temperature and high pressure. Although not shown in the examples, a platinum catalyst may also be used, while in liquid phase reactions, although also not shown in the examples, it is said that it is advantageous to use an inert catalyst such as methanol or cyclohexane.

Then FAM without adding ammonia
Example of obtaining 9% piperidine yield using Raney nickel as a catalyst under a pressure of 100 atmospheres or more [J.Am.chem.Soc. Vol. 67, p. 693 (1945)],
Example of obtaining 11% yield with copper chromite catalyst [Acta
Chem. Scand. Vol. 20, p. 591 (1966)].

On the other hand, some reports are known regarding attempts to produce 5-aminopentanol from 4HFAM. Keimatsu et al. reported an example of catalytic hydrogenation of 4HFAM hydrochloride as a raw material in the presence of a platinum oxide catalyst (3 wt% concentration relative to the raw material) to produce 5-aminopentanol hydrochloride in a relatively high yield [Pharmaceutical Journal No. 544] No. 506 (1927)]. However, Yahama et al.
It has been reported that hydrogenation of 4HFAM to 5-aminopentanol was attempted in the presence of catalysts such as platinum oxide, nickel, and chromium, but no formation of 5-aminopentanol or piperidine was observed in any case. [Industrial Chemistry Magazine, Vol. 53,
No. 24 (1950)].

As mentioned above, the technology for producing piperidine from tetrahydrofurfurylamine has not reached the level of industrial implementation because it requires industrially harsh conditions or the yield of the target product is too low. is the current situation. Also, 5
- Regarding the technology for producing aminopentanol, it is essential to treat the amine, which is the raw material and the target product, as a hydrochloride, which leads to corrosion of equipment, complexity of the process, and expensive catalysts such as platinum oxide It is considered to be an unfinished industrial technology as it involves the use of large amounts of.

The present inventors have intensively studied the reaction behavior of 4HFAM and the behavior of various reaction products in the presence of a catalyst for catalytic hydrogenation of 4HFAM, and have found that by using a specific catalyst and adopting a specific hydrogenation mode, 5-amino We established a technology to efficiently produce pentanol and piperidine, and completed the present invention.

That is, the present invention provides a method for producing 5-aminopentanol and piperidine by subjecting furfurylamine and/or tetrahydrofurfurylamine to a liquid phase catalytic hydrogenation reaction in the presence of a cobalt-based catalyst, wherein the reaction is carried out at a temperature of 150 to 300°C. temperature and 1~
A method for catalytic hydrogenation of furfurylamine and/or tetrahydrofurfurylamine, which is characterized in that the reaction is carried out under a hydrogen pressure of 100 atm and the conversion of tetrahydrofurfurylamine is controlled in the range of 3 to 70 mol%. This is what we provide.

In the hydrogenation reaction of tetrahydrofurfurylamine (), the oxygen-carbon bond of the furan ring is first broken and the ring is opened, and then nitrogen-containing 6 is formed by intramolecular dehydration.
A membered ring, piperidine (), is produced. on the other hand,
Cleavage between the carbon at position 5 of the furan ring and the oxygen yields undesirable by-products such as n-amylamine (). Furthermore, the reaction raw material (),
The target product and side reaction products are generally highly reactive under hydrogenation conditions, causing a condensation reaction between the two molecules and ring-opening polymerization of the raw material dimer () and its subsequent product, piperidine (). Undesirable reactions such as the formation of polyamines () are likely to occur.

In order to suppress these side reactions and promote only the hydrogenation ring-opening intramolecular dehydration reaction of the furan ring that leads to piperidine, it is necessary to effectively combine reaction factors such as the type of catalyst, reaction pressure, and reaction temperature. be. The present inventors conducted various studies from the above viewpoints, and
We have found that only cobalt-based catalysts can efficiently carry out the desired hydrogenation ring-opening reaction of furan rings under specific conditions. Furthermore, by carrying out the reaction under specific conditions using a cobalt-based catalyst,
A new fact has been discovered that it is possible to produce 5-aminopentanol (), which is a hydrogenated ring-opening product of 4HFAM () and a precursor of piperidine (), in a considerable yield. That is, as mentioned earlier, except for the special case of tetrahydrofurfurylamine () hydrochloride,
It has been revealed that it is possible to produce 5-aminopentanol (), which was previously thought to be impossible even using a wide variety of catalyst species.

Figure 1 shows an example of the distribution of various products with respect to the conversion rate of 4HFAM when 4HFAM is hydrogenated in the presence of a cobalt-based catalyst. According to this figure-1, the main primary product from the hydrogenation ring-opening reaction of the furan ring of 4HFAM is 5-aminopentanol (), and 5-aminopentanol is sequentially converted to piperidine. be understood. In addition, if the conversion rate of 4HFAM is too high, the ring-opening polymerization reaction of piperidine will occur.
The total yield of the desired products, 5-aminopentanol and piperidine, decreases.

That is, by controlling various reaction conditions, it is possible to control the production ratio of 5-aminopentanol and piperidine, and furthermore, in order to suppress the undesirable sequential reaction of piperidine, the conversion rate of the raw material 4HFAM can be controlled. By not increasing the conversion rate, and more specifically by controlling the conversion rate within the range of 3 to 70%, it is possible to produce the desired products, 5-aminopentanol and piperidine, in high yields. For example, in Figure 1, the conversion rate of 4HFAM is 25
5-aminopentanol selectivity when suppressed to %
It becomes possible to carry out the reaction at a high selectivity of 40 mol % and a piperidine selectivity of 55 mol %, that is, a total selectivity of the target product of 95 mol %.

Below, conditions for obtaining 5-aminopentanol and piperidine in good yield using tetrahydrofurfurylamine as a raw material will be described in more detail.

Catalyst The catalyst used in the present invention is cobalt-based. The term "cobalt-based catalyst" as used herein means a catalyst whose hydrogenation activity is at least mainly due to cobalt, and which contains a small amount of promoter or co-catalyst as is customary for metal catalysts such as cobalt. It also includes things.
An example of a preferred cocatalyst is rhenium.

One specific example of a preferred cobalt-based catalyst for use in the present invention is cobalt lanate.

Raney cobalt is developed with an alkali in an aqueous solution according to a conventional method. After development, it is washed until no alkali ions are detected, and then water is pushed out with a solvent used in the hydrogenation reaction before use. If the solvent for the hydrogenation reaction is not compatible with water, simply push out the water with a water-soluble and lipophilic solvent such as methanol or dioxane, and then push it out again with the desired solvent. good. Raney cobalt may also contain promoter metals such as manganese, iron, nickel, copper, molybdenum, tungsten, rhenium, chromium, and the like. The preferred content of each metal is about 0.01 to 0.3 (atomic ratio) of metal to cobalt.

Another group of cobalt-based catalysts preferred in the present invention are reduced cobalt. Reduced cobalt is usually cobalt oxide obtained by decomposing cobalt salts such as basic cobalt carbonate, cobalt carbonate, cobalt hydroxide, or cobalt nitrate, in which the coexisting functional groups are converted into gas and removed. It is obtained by heating in a stream of reducing gas such as hydrogen.

Reduced cobalt can be obtained with a carrier. Cobalt with a carrier can be obtained by allowing a carrier to coexist when producing a cobalt salt, or by mixing the carrier with a salt or cobalt oxide and then subjecting it to reduction treatment. As carriers, diatomaceous earth, silica,
Alumina, zirconia, magnesia and the like are preferred. If necessary, it may be molded and used.

The reduced cobalt may contain a promoter. A cobalt catalyst containing rhenium as a promoter can be obtained by co-precipitating a rhenium compound when producing a cobalt salt as described above, or by mixing a cobalt salt or cobalt oxide with a rhenium compound and then subjecting it to reduction treatment. . As the rhenium compound, perrhenic acid, ammonium perrhenate, etc. are usually preferred. A preferable rhenium content is about 0.01 to 0.3 (atomic ratio) to cobalt.

The reduction in the preparation of the abovementioned catalysts is usually carried out in a stream of steam at temperatures of from 150 to 500°C, preferably from 200 to 300°C. After reduction, it is used in a state where air is shut off. The method of impregnating the material with a reaction solvent and blocking air is simple and convenient. If necessary,
The reduction product may be brought into contact with air, carbon dioxide gas, etc. gradually in an inert gas to perform a so-called stabilization treatment so that it can be taken out into the air without igniting.

Organic Solvent In the present invention, the use of a solvent is not essential as long as the conversion rate of the raw material tetrahydrofurfurylamine is controlled within the range of 3 to 70%, and it can also be carried out by suspending the catalyst only in the raw material. However, the use of a solvent is generally expected to have the effect of suppressing the condensation reaction of the desired product, as long as it does not inhibit the hydrogenation reaction, and in fact often produces good results. When a solvent is used, it is appropriate to use it in an amount of 0.1 to 30 times, preferably 0.5 to 10 times, the amount of raw materials used.

Examples of solvents that are particularly effective in the present invention include hydrocarbon compounds, oxygen-containing compounds, and nitrogen-containing compounds. Hydrocarbon compounds include chain hydrocarbons such as n-hexane, n-octane, and liquid paraffin, cyclic hydrocarbons such as cyclopentane, cyclohexane, cyclooctane, and decalin, and benzene, toluene, tetralin, indane, and octahydroanthracene. These include aromatic hydrocarbons.

Oxygenated compounds include tertiary alcohols (especially saturated alcohols) and ethers.
For example, in the former, tert-butyl alcohol, 2-methyl-2-butanol, and 2-methyl-2-
Examples include hexanol.

Examples of ethers include diethyl ether, dipropyl ether, dibutyl ether, diamyl ether, and diisoamyl ether. In dialkyl ethers, the two alkyl groups may be different or each may be branched. Ethers also include dialkyl ethers of glycol, but in monoglycol dialkyl, it is preferable that the glycol moiety has 2 to 4 carbon atoms and the alkyl group has 1 to 5 carbon atoms (an alkyl group having 3 or more carbon atoms) (The base may be branched).
Furthermore, in the dialkyl ethers of polyethylene glycol as a group of ethers, the alkyl groups are the same as those mentioned above, and the number of linked ethoxy groups is 2 to 6, preferably 2 to 4. The ethers may be cyclic ethers, with dioxane and tetrahydrofuran being preferred solvents.

Among the nitrogen-containing compounds, tertiary amines (especially saturated amines) are preferred. Examples include trimethylamine and triethylamine. The alkyl groups substituted on the nitrogen atom may be different from each other, and a cyclic imine substituted with N-alkyl,
For example, N-pentylpiperidine is a preferred solvent. An ether bond may be present in the ring. For example, N-alkyl substituted morpholine and the like.

Hydrogenation reaction conditions In order to maintain a high selectivity to 5-aminopentanol and piperidine from the raw material 4HFAM, the conversion rate of 4HFAM should be controlled to 3 to 70 mol%, preferably 5 to 60 mol%. desirable. A lower conversion rate is preferable from the viewpoint of improving selectivity, but
If the conversion rate is too low, excessive labor is required to separate the target product from the raw material, which is not preferable. Furthermore, when the conversion rate is increased to 60 mol % or more, the sequential reactions of the target products become significant and the selectivity decreases rapidly.

In order to increase the production ratio of 5-aminopentanol, it is preferable to carry out the process in a low conversion range, and in order to increase the production ratio of piperidine, it is preferable to carry out the reaction at a rate of about 60 to 70% as long as undesirable sequential reactions can be suppressed. It is desirable to carry out the process at a high conversion rate. In addition, as a method of increasing the piperidine production ratio, it is also possible to recirculate the produced 5-aminopentanol to the reaction system, or to perform a separate dehydration reaction of 5-aminopentanol.

The main factors of effective hydrogenation reaction conditions for controlling the conversion rate of the raw material 4HFAM to 3 to 70 mol%, preferably 5 to 60% are reaction temperature, reaction time, and catalyst concentration.

The reaction temperature is about 150-300℃, preferably 160-300℃.
The temperature is around 250℃. When the reaction temperature is below the above range, the hydrogenation reaction of the furan ring of 4HFAM becomes extremely slow, and the dimerization reaction accompanied by the deammonization reaction of the raw material takes precedence, which tends to lower the selectivity of the target product. On the other hand, if the reaction temperature is above the above range, the rate of formation of the target product will be faster, but the successive reactions of the target product will be further promoted, which is not preferable.

The reaction time varies mainly depending on the reaction temperature and catalyst concentration, but is usually set in the range of 0.05 to 20 hours, preferably 0.1 to 10 hours.
In order to suppress the conversion rate of the raw materials to about 60%, the reaction time is set to be short as the reaction temperature increases.

The reaction pressure is approximately 1 to 100 atm as hydrogen partial pressure.
Preferably, about 3 to 60 atm is sufficient.

The amount of catalyst used is calculated by weight relative to the amount of raw materials used.
A suitable amount is 0.001 to 0.5 times, preferably 0.01 to 0.3 times.

A method in which a small amount of ammonia is allowed to coexist in the reaction system for the purpose of improving the selectivity of the target product is often effective. In this case, the appropriate amount of ammonia to be used is about 0.1 to 20 moles, preferably about 0.5 to 10 moles, per mole of the raw material. Use of a large amount of ammonia is not only undesirable because the total pressure becomes too high under the reaction conditions, but also undesirable because it reduces the rate of hydrogenation of the raw material.

The reaction can be carried out either continuously or batchwise. All of the above explanations have been limited to 4HFAM as the raw material amine, but when furfurylamine (FAM), which is a hydrogenated precursor of 4HFAM, is used as the raw material, a catalytic hydrogenation reaction can be carried out in the same way. 5
- Aminopentanol and piperidine can be produced. In addition, when using FAM as raw material,
Generally, it is better to generate 4HFAM by first hydrogenating the furan ring under relatively mild hydrogenation reaction conditions, and then performing the hydrogenation ring-opening reaction on the furan ring. A total yield of pentanol and piperidine can be obtained.

The method according to the present invention will be explained in more detail with reference to Examples below. It goes without saying that the present invention is not limited to these examples.

Catalyst Preparation Example 1 150g of cobalt nitrate [Co(NO ₃ ) ₂・6H ₂ O]
An aqueous solution of 141 g of ammonium bicarbonate (NH ₄ HCO ₃ ) dissolved in 650 ml of distilled water was added dropwise to an aqueous solution of 175 ml of distilled water with stirring over 2 hours while keeping the temperature at 20 to 22°C. The precipitate of basic cobalt carbonate was filtered and thoroughly washed with distilled water to obtain a basic cobalt carbonate salt cake (Co content: 9.09% by weight). 165g of this cake (15g as Co
1.96 g of ammonium perrhenate (NH ₄ ReO ₄ ) and 6.7 g of ammonium molybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ ] were added in the form of an aqueous solution.
After thoroughly kneading, the mixture is kneaded and dried while heating to around 80°C. The obtained powder was further dried at 100-110°C for 12 hours, treated at 450°C for 1 hour in an air stream, and then reduced at 300°C for 2 hours in a hydrogen stream to form a cobalt-rhenium-molybdenum catalyst. [Co:Re:Mo=1:0.03:0.15 (atomic ratio)] was obtained.

Catalyst preparation example 2 Raney-cobalt-manganese alloy (Co:Mn:Al
= 30:3.5:66.5) 17g to 85g of 25% NaOH aqueous solution
After gradually adding the mixture to the solution while stirring to avoid significant heat generation at room temperature, the mixture was heated to 50°C while stirring, and decanted after 1 hour.
Decantation washing was repeated 10 times with 200 ml of warm water, followed by washing 5 times with 200 ml of dioxane to obtain a Raney cobalt-manganese catalyst.

Example 1 0.2 g of the catalyst from Catalyst Preparation Example 2, 2.02 g of trahydrofurfurylamine as a raw material, and 18.18 g of dioxane as a solvent were charged into a 50 c.c. autoclave with stirring, hydrogen was introduced, and the mixture was heated at 200 to 210°C and 40 kg. /
cm ² and a stirring speed of 1000 rpm for 5 minutes. After cooling the autoclave, the reactants were separated from the catalyst and analyzed using a gas chromatograph. As a result, the conversion rate of tetrahydrofurfurylamine was 23.5%.
The selectivity of the reacted tetrahydrofurfurylamine to 5-aminopentanol was 19.2 mol%, the selectivity to piperidine was 76.2 mol%, and the total selectivity to the desired product was 95.4 mol%.

Comparative Example 1 When the reaction was carried out under the same conditions as in Example 1 except that the reaction time was 60 minutes, the conversion rate of tetrahydrofurfurylamine was 98%, the selectivity to 5-aminopentanol was 0.5 mol%, The selectivity to piperidine is 77.4 mol%, and the selectivity to the target product is
It decreased to 77.9 mol%.

Example 2 A reaction was carried out under the same reaction conditions as in Example 1, except that 0.5 g of the catalyst from Catalyst Preparation Example 1, 5.05 g of tetrahydrofurfurylamine as a raw material, and 5.0 g of dioxane as a solvent was used. The conversion rate of amine was 22.5%, and the selectivity to 5-aminopentanol, piperidine, and the desired product were 41.8, 47.8, and 89.6 mol%, respectively.

Example 3 Using 0.2 g of the catalyst from Catalyst Preparation Example 1, 2.02 g of tetrahydrofurfurylamine as a raw material, and 18.18 g of dioxane as a solvent, the reaction temperature was 210°C, 40
The conversion rate of tetrahydrofurfurylamine was changed by changing the reaction time from 5 minutes to 40 minutes at Kg/cm ² and stirring speed of 1000 rpm, and the changes in each product with respect to the conversion rate were investigated. The results are shown in Figure 1. .

Example 4 Using 1.5 g of the catalyst from Catalyst Preparation-1 and 15 g of tetrahydrofurfurylamine as a raw material, the reaction was carried out at a reaction temperature of 210°C and a reaction pressure of 50 kg/cm ² for 10 minutes. The conversion rate of tetrahydrofurfurylamine was as follows.
At 40.5%, the selectivity to 5-aminopentanol, piperidine and desired product was 32.0, respectively.
They were 49.5 and 81.5 mol%.

Comparative Example 2 When the reaction was carried out under the same reaction conditions as in Example 4 except that the reaction time was 60 minutes, the conversion rate of tetrahydrofurfurylamine was 92.4%, and the conversion rate to 5-aminopentanol, piperidine and the target product was 92.4%. The selectivity decreased to 3.5, 45.0 and 48.5 mol%, respectively.

Example 5 0.5 g of the catalyst from Catalyst Preparation-2, 5.05 g of tetrahydrofurfurylamine as a raw material, 5.0 g of dioxane as a solvent, and ammonia at a molar ratio of 2 to the raw material were added, and the reaction temperature was 185°C and the reaction pressure was When the reaction was carried out at 60Kg/ ^cm2 for 15 minutes, the conversion rate of tetrahydrofurfurylamine was 45.0%.
The selectivities for 5-aminopentanol, piperidine and desired product were 52.5, 40.9 and 5, respectively.
It was 93.4 mol%.

Example 6 When the reaction was carried out under the same conditions as in Example 4 except that ammonia was added at a molar ratio of 1.2 times that of tetrahydrofurfurylamine and the reaction time was 15 minutes, the conversion rate of tetrahydrofurfurylamine was as follows.
At 30.0%, the selectivity to 5-aminopentanol, piperidine and desired product was 38.0, respectively.
They were 51.2 and 89.2 mol%.

Comparative Example 3 When the reaction was carried out under the same conditions as in Example 6 except that the reaction time was 60 minutes, the conversion rate of tetrahydrofurfurylamine was 84.8%, and the selectivity to 5-aminopentanol, piperidine and the target product was 84.8%. were 4.9, 64.8 and 69.7 mol%, respectively.

Example 7 A reaction was carried out under the same conditions as in Example 1, except that furfurylamine was used instead of tetrahydrofurfurylamine as a raw material and the reaction time was 10 minutes. The conversion of furfurylamine was 95%, and the selectivity to tetrahydrofurfurylamine, 5-aminopentanol and piperidine were respectively
They were 71.0, 7.1 and 19.8 mol%.

The conversion rate of 4HFAM calculated from these values is 28.9
%, and the selectivities to 5-aminopentanol, piperidine, and the target compound based on 4HFAM were 24.4, 68.4, and 92.8 mol%, respectively.

Example 8 0.5 g of the catalyst from Catalyst Preparation Example 1, 5.0 g of furfurylamine as a raw material, and 5.0 g of dioxane as a solvent were charged, and after reacting at a reaction temperature of 100°C and 40 kg/cm ² for 180 minutes (usually at this stage, furfurylamine was The furan ring was almost completely hydrogenated to produce tetrahydrofurfurylamine, and a small amount of 5 was produced.
-The total yield of aminopentanol and piperidine was about 98-99 mol%), the reaction temperature was raised to 210°C, and the reaction was continued for an additional 5 minutes. The conversion rate of furfurylamine was 100%, and the yields of tetrahydrofurfurylamine, 5-aminopentanol, and piperidine were 76.3 and 76.3, respectively.
They were 9.6 and 10.8 mol%.

The conversion rate of 4HFAM calculated from these values is 23.7
%, and the selectivities to 5-aminopentanol, piperidine, and the target compound based on 4HFAM were 40.5, 45.6, and 86.1 mol%, respectively.

[Brief explanation of drawings]

Figure 1 shows Example 3, which is an example of the method of the present invention.
FIG. 2 is a correlation diagram between the conversion rate of tetrahydrofurfurylamine and the selectivity to each product, showing the reaction results. In Figure 1, [] is 5-aminopentanol selectivity, [] is piperidine selectivity, []+[]
indicate the amine polycondensate selectivity, respectively.

Claims (1)

[Claims] 1. A method for producing 5-aminopentanol and piperidine by subjecting furfurylamine and/or tetrahydrofurfurylamine to a liquid phase catalytic hydrogenation reaction in the presence of a cobalt-based catalyst, in which the reaction
Furfurylamine and/or tetrahydrofurfurylamine, which is characterized in that the reaction is carried out at a temperature of 150 to 300°C and a hydrogen pressure of 1 to 100 atm, with the conversion rate of tetrahydrofurfurylamine controlled in the range of 3 to 70 mol%. Catalytic hydrogenation method of hydrofurfurylamine.