JP2946440B2 - Reductive alkylation / reductive amination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 for synthesizing chemical products used in the fields of food, medicine, agrochemicals and the like.

[0002]

2. Description of the Related Art Reductive alkylation and reductive amination are reactions in which ammonia and amines are reductively alkylated with carbonyl compounds such as aldehydes and ketones. It becomes a reaction to be aminated. This reaction is roughly divided into two depending on the difference in the reduction method.

[0003] One is a method using a reducing agent such as formic acid, formamide, sodium borohydride, and sodium cyanoborohydride. This was discovered in 1885 as a reductive amination (alkylation) of carbonyl compounds with amines performed by Leukart using ammonium formate. Then, in 1892, Warrach used formic acid, moderated the reaction conditions, suppressed side reactions, and extended the system to various systems. For this reason, this reaction is also called a Leukart-Wallach reaction. However, this method has problems that the reducing agent cannot be used repeatedly and that it is often difficult to separate the reducing agent from the reaction product.

[0004] Another method is a reaction in which a catalytic reduction is carried out in a hydrogen atmosphere using a metal catalyst such as platinum, nickel or cobalt. This reaction has the advantage that the operation is simpler and the reaction product is easily separated from the catalyst as compared with the method using a reducing agent. At this time, when a noble metal such as palladium, rhodium, or platinum is used, the catalytic activity is high and the reaction proceeds at low temperature and low pressure. However, it is, of course, expensive and not suitable for industrial use. Also,
When a relatively inexpensive metal such as nickel, cobalt, or copper is used, the catalytic activity is low, and high temperature and high pressure conditions are required.

[0005] Hydrogen storage alloys that have been recently developed and are attracting attention for their applications are currently used in the fields of automobiles, heat pumps, and indoor air conditioning systems. Examples of hydrogen storage alloys include LaNi ₅ and MgNi. , TiFe, etc., and the functions such as hydrogen storage amount, discharge pressure, and discharge temperature of the alloy vary greatly depending on the constituent metals thereof. Therefore, the selection of the alloy is important for its use.

As an example of the hydrogenation reduction reaction using a hydrogen storage alloy, hydrogen reduction of olefins, hydrogenation of carbon monoxide, and synthesis of ammonia are described in “Hydrogen Storage Alloy Data Book” (Yono Shobo 1987). ,further,
Atmospheric pressure hydrogenolysis of methyl oleate to form C ₁₈ alcohols is described in The Chemical Society of Japan (The 54th Annual Spring Meeting 1987)
Year). Also, hydrogenation of fats and oils (Japanese Patent Application Laid-Open No. 63-268799), production of sugar alcohols (Japanese Patent Application No. 2-219100), reduction of disulfide bonds (Japanese Patent Application No.
-277808) and the Deprotection Law (Japanese Patent Application No. 2-277809) have also been reported.

However, there is no report on the case where reductive alkylation / reductive amination was performed using a hydrogen storage alloy.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to the use of a highly reactive hydrogen storage alloy in performing reductive alkylation and reductive amination of a compound having a carbonyl group using catalytic reduction. No need to use any catalyst at all, and a large amount of hydrogen discharged from the hydrogen storage alloy can be used at low pressure. Using simple equipment, safe and inexpensive reductive alkylation / reductive amination It is an object of the present invention to provide a method for performing the above.

[0009]

According to the present invention, a compound having a carbonyl group is allowed to coexist with an amino compound such as ammonia to perform reductive alkylation and reductive amination.
(Representing rare earth element or Ca element) and catalytic hydrogenation with hydrogen released from the alloy using a hydrogen storage alloy whose main phase is a compound having hexagonal CaCu ₅ type crystal structure with Ni as an essential element And performing reductive alkylation and reductive amination.

Hereinafter, the present invention will be described in detail. 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 containing M (representing a rare earth element or Ca element) and Ni as essential elements.
In addition, the CaCu _5- type crystal phase contained in the hydrogen storage alloy is 50%.
% Or more, with the balance being intermetallic compounds other than the main phase, impurities, additional elements, etc., present as a second phase or a mixed phase.

[0011] These hydrogen storage alloys themselves have a high catalytic activity for the reduction reaction. Therefore, depending on the type of the alloy used and the setting of the reduction reaction temperature of the reaction solution, 20 kg / cm ² is required.
It is possible to safely perform reductive alkylation / reductive amination at a high conversion under a condition of a hydrogen gas pressure of less than. After the hydrogen storage alloy is pulverized, hydrogen is stored in the alloy at a temperature of 0 ° C. or lower in a hydrogen atmosphere for a certain period of time to absorb hydrogen.

In the present invention, the reaction solution and the hydrogen storage alloy preliminarily storing hydrogen are put into a reaction tank, and after deaeration, the reaction solution is maintained at a constant temperature while stirring, or by a jacket method. The hydrogen storage alloy is sealed in a tray type column capable of holding the hydrogen storage alloy at a certain temperature, and the reductive alkylation and reductive amino acid are circulated by circulating the reaction solution maintained at a certain temperature. Perform the conversion.

After the reaction, the hydrogen gas and the reaction liquid 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 characteristics of the hydrogen storage alloy, in that the reaction can be sufficiently performed under the condition that the hydrogen gas pressure is less than 20 kg / cm ² , and is advantageous in terms of maintenance and safety of the manufacturing apparatus. As the hydrogen storage alloy, a plating powder, a surface treatment powder, and an encapsulated alloy of copper, silicon, or the like, which are surface-modified for the purpose of improving corrosion resistance and thermal conductivity, can be used in the present invention.

[0014]

The present invention will be specifically described below with reference to examples. Example 1 A dead end type reaction vessel having a capacity of 1 liter was charged with 50 g of a hydrogen storage alloy CaNi _{5 in} which hydrogen was stored in advance. Then, the mixture was degassed at 25 ° C. and a degree of vacuum of 750 mmHg for 5 minutes.
0ml and 17g ammonia dissolved 150ml ethanol solution
Was poured into each container. Thereafter, the reaction temperature was adjusted to 25 ° C. while stirring. At this time, the hydrogen gas pressure in the container was 6.0 kg / cm ² . After 40 minutes, the reaction solution was analyzed by GC-MS, and it was confirmed that benzylamine and dibenzylamine were formed, respectively. By liquid chromatography, the yields were 81% and 7%, respectively.
Met.

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

Example 3 A dead end type reaction vessel having a capacity of 1 liter was charged with 50 g of hydrogen storage alloy LaNi _{5 in} which hydrogen was stored in advance. Then, the mixture was degassed at 25 ° C. and a vacuum of 750 mmHg for 5 minutes, 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 poured into the reaction vessel. Thereafter, the reaction temperature was adjusted to 25 ° C. while stirring. At this time, the hydrogen gas pressure in the container was 6.0 kg / cm ² . Two hours later, when the reaction solution was analyzed by GC-MS, 1-
It was confirmed that phenoxy-2- (2-hydroxyethylamino) propane was generated, and the yield was 61% by liquid chromatography.

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

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

[0019]

As described above, when reductive alkylation and reductive amination are performed using a hydrogen storage alloy according to the present invention, the hydrogen storage alloy itself has a high catalytic activity, and therefore, the conventional nickel storage material such as nickel is used. Hydrogen gas pressure 20 without the need for a catalyst
The reaction can be performed efficiently under highly safe conditions of less than kg / cm ² , and the reaction can be repeatedly performed. Further, the hydrogen storage alloy can store a larger amount of hydrogen gas than 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 between the reaction solution and the hydrogen storage alloy can be greatly reduced.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C07C 213/02 C07C 213/02 217/16 217/16 (72) Inventor Shunichi Dosako 5-15-Kitaura, Urawa-shi, Saitama 39-616 (72) Inventor Eiji Eiji 1-6-6-802 Irumagawa, Sayama City, Saitama Prefecture (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 209/26 C07B 31/00 C07B 43/04 C07C 211/27 C07C 211/54 C07C 213/02 C07C 217/16

Claims (1)

(57) [Claims] When a compound having a carbonyl group coexists with an amino compound and an amine is obtained 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 it with hydrogen released from the alloy Reductive alkylation characterized by that
Reductive amination method.