JPH06173056A - Production of alkylurea compound by electroysis - Google Patents

Abstract

PURPOSE:To produce an alkylurea compd. under mild conditions by electrolyzing carbon monoxide and an alkylamine with an anode contg. a Pt group element. CONSTITUTION:Carbon monoxide and an alkylamine such as methylamine, dimethylamine or ethylamine are electrolyzed with an anode contg. a Pt group element such as Pd, Pt or Ru. At this time, methanol acetonitrile or the like is used as a solvent, sodium iodide or the like is used as a supporting electrolyte and conditions in electrolysis are regulated to about 0-100 deg.C temp., about 1-20atm pressure and about 1-20A/dm<2> current density. The objective alkylurea compd. is easily produced under mild conditions.

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 an alkylurea compound useful as a synthetic raw material for pharmaceuticals, agricultural chemicals, dyes and the like from carbon monoxide and an alkylamine by an electrolytic reaction.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an alkylurea compound, 1) a method of reacting an alkylamine with carbon dioxide (Japanese Patent Publication No. 62-9107), and 2) a method of reacting an alkylamine with urea (Japanese Patent Publication No. 2). -7945),
3) Method of reacting alkylamine with carbon monoxide and oxygen (Japanese Patent Publication No. 2-57064, J. Am. Chem.
Soc., 93, 6344 (1971) and the like are known. However, the methods 1) and 2) require high temperature and high pressure reaction conditions. The method 3) has a risk of explosion and the like because a mixed gas of carbon monoxide and oxygen is heated and used, and further, there is a problem that selenium or the like having strong toxicity is used as a catalyst.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned various problems in the prior art and develops a mild and convenient method for producing an alkylurea, which comprises carbon monoxide and an alkylamine. To provide a method for electrolytically producing an alkylurea compound with good results under mild conditions.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that an anode containing a platinum group element is used to electrolyze carbon monoxide and an alkylamine. As a result, they found that an alkylurea compound was produced under mild conditions, and reached and completed the present invention. The production reaction of the alkylurea compound in the present invention is
It can be represented by the following formula.

[0005]

[Chemical formula 1] 2HNRR '+ CO → RR'NC (O)
NRR ′ + H _{2 In the} formula, R and R ′ are hydrogen or an alkyl group having 1 to 8 carbon atoms, and may be the same or different from each other.

The alkylamine used in the present invention is a primary or secondary aliphatic amine having 1 to 8 carbon atoms, specifically, methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropyl. Examples thereof include amine, butylamine, dibutylamine and the like.

In the method of the present invention, the platinum group element used for the anode is palladium, platinum, ruthenium, rhodium, iridium or osmium, and these metals or compounds can be used. Examples of the compound include oxides, halides, nitrates, complex compounds and the like. Further, it is possible to use one or more of these elements in combination, and there is no particular limitation on the shape or the like as long as it is an electrode containing these platinum group elements. It is possible to use, for example, a film, or an electrode used in a usual electrolytic production method, on which a platinum group element is vapor-deposited, plated, or pressure-bonded, or those compounds are supported.

The solvent used in the present invention is not particularly limited as long as it is a solvent used in a usual electrolytic production method, but has an oxidation potential higher than that of the starting alkylamine in order to avoid side reactions involving the solvent. It is desirable to use a low one. Examples include acetonitrile, dimethylformamide, methanol and the like. It is also possible to use the alkylamine itself as the electrolytic solvent.

The supporting electrolyte used in the present invention is not particularly limited as long as it can be dissolved in a solvent and an amine as a raw material, and as a cation component, an anion such as an ion of a Group 1A element of the periodic table, a quaternary alkylammonium ion or the like, an anion. A supporting electrolyte composed of a combination of chlorine ion, bromine ion, iodine ion and the like can be used as a component. Among the anion components, iodide ion is particularly preferable because it has high selectivity for the alkylurea compound. The supporting electrolyte in the present invention is 0.1 to 20% by weight based on the raw material amine.
Is preferred.

The electrolytic cell used in the present invention may be either a diaphragm type or a diaphragmless type, but it is preferable to use the diaphragmless electrolytic cell from the viewpoint of economy. The material of the diaphragm in the case of using the diaphragm type electrolytic cell is not particularly limited as long as it is used in a usual electrolytic production method.
With respect to the shape and arrangement of the electrode pair and the energization method, the type adopted in a usual electrolytic manufacturing method can be used. In particular, the distance between the anode and the cathode is preferably as small as possible in order to improve the current efficiency and the voltage efficiency, and it is practically preferable to use a capillary gap cell or the like. The method of energizing the electrode pair may be either a monopolar method or a bipolar method, and an economically effective method can be selected.

The carbon monoxide used in the present invention preferably has a high purity, but it is desirable that the carbon monoxide does not contain oxidizing gas as much as possible in order to prevent the progress of side reactions such as oxidation of alkylamine. Further, the molar ratio of carbon monoxide and alkylamine in the electrolytic cell is not particularly limited as long as both coexist, but a condition with a large amount of carbon monoxide is preferable.

The conditions of electrolysis temperature, electrolysis pressure and current density in the present invention are not particularly limited, but are 0 to 100 ° C., 1 to
The pressure may be in the range of 20 atm and 1 to 20 A / dm ² . When carbon monoxide and lower alkylamine are supplied to the electrolytic cell as gas components, the reaction proceeds even at normal pressure, but some pressurization conditions are required to obtain a sufficient amount of dissolution in the electrolytic solvent. Lower is preferred.

[0013]

By carrying out an electrolytic reaction using an anode containing a platinum group element, it has become possible to produce an alkylurea compound from carbon monoxide and an alkylamine under mild conditions.

[0014]

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. Example 1 Methanol 184 was added to a 250 ml separable flask.
g and 3.8 g of sodium iodide were taken and mixed. ^Two rectangular palladium metal membrane electrodes (0.2 mm thick) having a geometric surface area of about 17 cm ² and carbon electrodes were fixed with a distance between electrodes of 4 mm, and each was connected as an anode and a cathode and immersed in the above electrolyte solution. . Monomethylamine was circulated and dissolved in the electrolytic solution. The dissolved amount was 3.8 g. There, 1.8 L of carbon monoxide was circulated while bubbling under normal pressure, and a direct current was passed under constant current control at a current density of 5.8 A / dm ² . The electrolysis voltage was about 7 V during the electrolysis reaction. The liquid is stirred with a magnetic stirrer, and the temperature of the electrolytic solution during the electrolytic reaction is about 15
It was kept at 25 ° C. 49.7mF After energizing, 1.
The formation of 6 g of 1,3-dimethylurea and 0.05 g of methyl N-methylcarbamate also leads to 0.0
The production of 4 g of hydrogen was observed. The current efficiency was 73%.

Example 2 Using the same electrolytic apparatus and method as in Example 1, 1.8 L of carbon monoxide was bubbled into an electrolytic solution containing 180 g of methanol containing 3.8 g of dimethylamine and 3.8 g of sodium iodide under normal pressure. While circulating, current density is 5.8A /
Energized at dm ² . The electrolysis voltage is 7 to 8V during the electrolysis reaction.
Was the value of. After energizing at 60.4 mF, it is 1.9 in the electrolyte.
The production of g of 1,1,3,3-tetramethylurea and 0.35 g of methyl N, N-dimethylcarbamate and the production of 0.05 g of hydrogen in the circulating gas were observed. The current efficiency was 54%.

Example 3 Using a platinum plate on a titanium plate (geometric surface area of about 17 cm ² ) as an anode, and using the same electrolytic apparatus and method as in Example 1, methanol 181 containing 3.5 g of methylamine was used.
g, and 1.8 g of carbon monoxide were circulated while bubbling through an electrolytic solution containing 3.8 g of sodium iodide, and electricity was supplied at a current density of 5.8 A / dm ² . After energizing 19.4 mF,
Formation of 0.55 g of 1,3-dimethylurea was observed in the electrolytic solution. The current efficiency was 64%.

Claims (1)

[Claims] 1. A method for producing an alkylurea compound from carbon monoxide and an alkylamine by an electrolytic reaction using an anode containing a platinum group element.