JPH0672968A - Reductive alkylation-reductive amination method - Google Patents

Abstract

PURPOSE:To efficiently perform the reductive alkylation.reductive amination reaction useful in the fields of foods, medicines, agrichemicals, etc., in a high yield under a highly safe condition by hydrogenating a carbonyl group-containing compound with a specific hydrogen storage alloy in the coexistence of an amino compound. CONSTITUTION:A carbonyl group-containing compound such as benzaldehyde is reduced with hydrogen in the coexistence of an amino compound such as methylamine to perform the reductive alkylation/reductive amination reaction, the hydrogen being released from a hydrogen storage alloy containing as a main phase a compound having a hexagonal CaCi5 type crystal structure containing M (rare earth element or Ca element) and Ni as essential elements.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a reductive alkylation / reductive amination method using a hydrogen storage alloy. INDUSTRIAL APPLICABILITY The method of the present invention is useful in the synthesis of chemical products used in the fields of food, medicine, agricultural chemicals and the like.

[0002]

2. Description of the Related Art The reductive alkylation method / reductive amination method is a reaction in which ammonia or amine is reductively alkylated with a carbonyl compound such as an aldehyde or a ketone. The reaction is amination. This reaction can be roughly divided into two depending on the reduction method.

One is a method using a reducing agent such as formic acid, formamide, sodium borohydride, sodium cyanoborohydride and the like. This was discovered in 1885 as a reductive amination (alkylation) reaction of carbonyl compounds with amines performed by Leukart using ammonium formate. In 1892, Warrach used formic acid to moderate the reaction conditions and suppress side reactions to expand into various systems. Therefore, this reaction is also called the Leukart-Wallach reaction. However, this method has a problem that the reducing agent cannot be repeatedly used and that it is often difficult to separate the reducing agent and the reaction product.

Another method is a catalytic reduction reaction using a metal catalyst such as platinum, nickel or cobalt in a hydrogen atmosphere. This reaction has the advantages that the operation is simpler and the reaction product and the catalyst are easier to separate than the method using a reducing agent. At this time, when a noble metal such as palladium, rhodium or platinum is used, the catalytic ability is high and the reaction proceeds at low temperature and low pressure. However, as a matter of course, it is expensive and not suitable for industrial use. Also,
When a relatively inexpensive metal such as nickel, cobalt or copper is used, it has a low catalytic activity and requires high temperature and high pressure conditions, so that it is necessary to use an expensive heat and pressure resistant container as the reaction container.

Hydrogen storage alloys, which have been developed in recent years and are attracting attention for their applications, are currently used in the fields of automobiles, heat pumps, indoor air-conditioning systems, and the like. Examples of hydrogen storage alloys include LaNi ₅ and MgNi. , TiFe, etc., and the functions of the alloy such as hydrogen storage capacity, discharge pressure, discharge temperature, etc. differ greatly depending on the constituent metals, so the selection of the alloy is important for its use.

By the way, as an example of the hydrogenation reduction reaction with a hydrogen storage alloy, hydrogenation reduction of olefins, hydrogenation of carbon monoxide and synthesis of ammonia are described in "Hydrogen Storage Alloy Data Book" (published by Yono Shobo 1987). ,further,
Regarding the C ₁₈ alcohol formation reaction by atmospheric pressure hydrogenolysis of methyl oleate, the Chemical Society of Japan (The 54th Annual Meeting of the Spring 1987)
(Held annually). Further, hydrogenation of fats and oils (JP-A-63-268799), production of sugar alcohol (Japanese Patent Application No. 2-219100), reduction of disulfide bond (Japanese Patent Application No.
-277808) and the deprotection law (Japanese Patent Application No. 2-277809).

However, there is no report on an example in which reductive alkylation / reductive amination is carried out using a hydrogen storage alloy.

[0008]

DISCLOSURE OF THE INVENTION The present invention utilizes a highly reactive hydrogen storage alloy in carrying out reductive alkylation / reductive amination of a compound having a carbonyl group by using catalytic reduction. It is not necessary to use any of the above catalysts, and a large amount of hydrogen exhausted from the hydrogen storage alloy can be used at low pressure. Using a simple device, it is safe and inexpensive to carry out reductive alkylation / reductive amination. It is an object to provide a method of doing.

[0009]

According to the present invention, when a compound having a carbonyl group is allowed to coexist with an amino compound such as ammonia to carry out reductive alkylation / reductive amination, M
Catalytic hydrogenation with hydrogen released from a hydrogen storage alloy whose main phase is a compound having a hexagonal CaCu ₅ type crystal structure (representing a rare earth element or Ca element) and Ni as an essential element. And reductive alkylation / reductive amination is performed.

The present invention will be described in detail below. Examples of the compound having a carbonyl group used in the present invention include formaldehyde, acetaldehyde, acetone,
Various compounds such as benzaldehyde may be mentioned. The hydrogen storage alloy used in the present invention has, as a main phase, a compound having a hexagonal CaCu ₅ type crystal structure in which M (representing a rare earth element or Ca element) and Ni are essential elements.
In addition, the CaCu ₅ type crystal phase contained in the hydrogen storage alloy is 50
It is contained by weight% or more, and the rest contains intermetallic compounds other than the main phase, impurities, additional elements, etc. as the second phase or mixed phase.

Since these hydrogen storage alloys themselves have high catalytic ability for the reduction reaction, depending on the type of alloy used and the reduction reaction temperature of the reaction solution, 20 kg / cm ²
It is possible to safely carry out reductive alkylation / reductive amination with a high reaction rate and under a hydrogen gas pressure of less than. After pulverizing this hydrogen storage alloy, hydrogen is absorbed in the alloy by holding it at a temperature of 0 ° C. or lower in a hydrogen atmosphere for a certain period of time.

In the present invention, the reaction solution and the hydrogen storage alloy in which hydrogen has been occluded in advance are placed in a reaction tank, and after degassing, the reaction solution is maintained at a constant temperature while stirring or by a jacket method. By enclosing the hydrogen storage alloy in a tray column that allows the hydrogen storage alloy to be maintained at a constant temperature, and circulating the reaction solution maintained at a constant temperature, reductive alkylation / reductive amino To convert.

After the reaction, the hydrogen gas and the reaction solution are recovered and the hydrogen storage alloy is cooled. This hydrogen storage alloy can be repeatedly used for the next reduction reaction by recycling hydrogen. The present invention is advantageous in terms of the maintenance and safety of the manufacturing apparatus, because the hydrogen storage alloy can be sufficiently reacted under the hydrogen gas pressure of less than 20 kg / cm ^{2 due to} the characteristics of the hydrogen storage alloy. Further, as the hydrogen storage alloy, a plating powder surface-modified for the purpose of improving corrosion resistance, thermal conductivity, etc., a surface-treated powder, an encapsulated alloy of copper or silicon, etc. can be used in the present invention.

[0014]

EXAMPLES The present invention will be specifically described with reference to the following examples. Example 1 50 g of hydrogen storage alloy CaNi _{5 in} which hydrogen was stored in advance was placed in a dead end type reaction vessel having a volume of 1 liter. Then, degassed at 25 ° C. and a vacuum degree of 750 mmHg for 5 minutes, and cooled with ethanol solution containing benzaldehyde (109 g) 15
150 ml ethanol solution containing 0 ml and 17 g ammonia
Was poured into each container. Then, the reaction temperature was adjusted to 25 ° C. with stirring. The hydrogen gas pressure inside the container at this time was 6.0 kg / cm ² . After 40 minutes, when the reaction solution was analyzed by GC-MS, it was confirmed that benzylamine and dibenzylamine were produced, respectively. By liquid chromatography, the respective yields are 81% and 7%
Met.

Example 2 In a dead-end type reaction vessel having a volume of 1 liter, 50 g of hydrogen storage alloy LaNi _{5 in} which hydrogen was stored in advance was placed. Then, degassed at 25 ° C. and a vacuum degree of 750 mmHg for 5 minutes and cooled, and 170 ml of a 22% by weight concentration of 2,3-dimethoxybenzaldehyde methanol solution and 23% by weight concentration of a methylamine methanol solution of 100 ml were placed in respective containers. Injected. Then, the reaction temperature was adjusted to 25 ° C. with stirring. The hydrogen gas pressure inside the container at this time was 6.5 kg / cm ² . After 2 hours, when the reaction solution was analyzed by GC-MS, it was confirmed that N-methyl-2,3-dimethoxybenzylamine had been produced, and the yield was 88% by liquid chromatography.

Example 3 In a dead-end type reaction vessel having a volume of 1 liter, 50 g of hydrogen storage alloy LaNi _{5 in} which hydrogen was stored in advance was placed. Then, the mixture was degassed for 5 minutes at 25 ° C. and a vacuum degree of 750 mmHg, and 200 ml of a methanol solution of phenoxyacetone having a concentration of 38% by weight and 200 ml of a methanol solution of ethanolamine having a concentration of 15% by weight were respectively injected into the reaction vessel. Then, the reaction temperature was adjusted to 25 ° C. with stirring. The hydrogen gas pressure inside the container at this time was 6.0 kg / cm ² . After 2 hours, the reaction solution was analyzed by GC-MS.
It was confirmed that phenoxy-2- (2-hydroxyethylamino) propane had been produced, and the yield was 61% by liquid chromatography.

Example 4 In a dead-end type reaction vessel having a capacity of 1 liter, 50 g of hydrogen storage alloy CaNi _{5 in} which hydrogen was stored in advance was placed. Then, degassed at 25 ° C. and a vacuum degree of 750 mmHg for 5 minutes, and cooled with methanol solution containing 109 g of benzaldehyde.
150 ml of a methanol solution containing 0 ml and 8.5 g of ammonia
Was poured into each container. Then, the reaction temperature was adjusted to 25 ° C. with stirring. The hydrogen gas pressure inside the container at this time was 6.0 kg / cm ² . After 90 minutes, the reaction solution was analyzed by GC-MS, and it was confirmed that dibenzylamine and benzylamine were produced, respectively, and the yields were 80% and 15%, respectively, by liquid chromatography. It was

Example 5 A dead-end type reaction vessel having a volume of 1 liter was charged with 50 g of hydrogen storage alloy LaNi _4.3 Al _{0.3 in} which hydrogen was stored in advance. Then, 100 ml of a 15 wt% concentration formaldehyde ethanol solution and 200 ml of a 42 wt% concentration diphenylamine ethanol solution, which had been degassed for 5 minutes at 25 ° C. and a vacuum degree of 750 mmHg, were respectively injected into the container. Then, the reaction temperature was adjusted to 25 ° C. with stirring. The hydrogen gas pressure inside the container at this time was 6.7 kg / cm ² . 40 minutes later,
When the reaction solution was analyzed by GC-MS, it was confirmed that methyldiphenylamine was produced, and the yield was 62% by liquid chromatography.

[0019]

As described above, when the reductive alkylation / reductive amination is performed using the hydrogen storage alloy according to the present invention, the hydrogen storage alloy itself has a high catalytic ability. Hydrogen gas pressure of 20 without the need for a catalyst
It is possible to efficiently carry out the reaction under highly safe conditions of less than kg / cm ² , and it is possible to repeatedly use the reaction. Further, the hydrogen storage alloy can store a large amount of hydrogen gas as compared with an industrial hydrogen storage device, and can operate at a low pressure as described above. Further, when the upflow tray column as described above is used, there is an operational advantage that the load on the separation of the reaction solution and the hydrogen storage alloy can be significantly reduced.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C07C 211/54 9280-4H 213/02 7457-4H 217/16 7457-4H 217/58 7457-4H // C22C 19/00 F (72) Inventor Shunichi Dosako 5-15-39-616 Kitaurawa, Urawa-shi, Saitama Prefecture (72) Inventor Eiji Ike 1-6-6-802 Irumagawa, Sayama-shi, Saitama Prefecture

Claims (1)

[Claims] 1. When a compound having a carbonyl group is made to coexist with an amino compound to obtain an amine by a reduction reaction,
Using a hydrogen storage alloy whose main phase is a compound having a hexagonal CaCu ₅ type crystal structure with M (representing a rare earth element or Ca element) and Ni as essential elements, and reducing with hydrogen released from the alloy Reductive alkylation characterized by
Reductive amination method.