JPH032157A - Production of ureas - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to improvements in methods for producing ureas.

[Prior Art] As a method for producing ureas, a method has been proposed in which an amine and carbon monoxide are reacted using a catalyst such as cobalt carbonyl, silver acetate, sulfur, selenium, or a platinum group metal.

Furthermore, when nitrobenzene and carbon monoxide are reacted in the presence of hydrogen under a ruthenium complex catalyst, N,N'
-It is known that diphenyl urea and aniline are produced.

In the above-mentioned method for producing ureas using amine and carbon monoxide, a method using cobalt carbonyl or silver acetate is described in Can, J. Chell, 40171, respectively.
g (1982), J.Org.Chem., 3726
70 (1972), but the yield and selectivity for ureas are not very high. In addition, a method using sulfur or selenium is described in J, Org, Chem, 2633.
09 (1981), J. Allier.

Cheffl, Soc, 938344 (1970). Although these methods generally have high yield and selectivity, they require complicated operations to separate and recover catalyst components.

Methods using platinum group metals are described, for example, in Japanese Patent Publication No. 53-41
123, and J,Org,Chem,, 4Q281.
9 (1975), and further proposed in Japanese Patent Laid-Open No. 144363/1983. The former has a low yield of about 60%. In addition, in the latter case, the catalyst system is complex, containing oxygen gas as well as halogen compounds and carbon oxides in addition to palladium, which is the main metal catalyst, and requires complicated operations to recover the catalyst. There is a problem in that the reactor requires the use of expensive materials with excellent corrosion resistance.

On the other hand, Inorg, Chem, 9342 (1970)
When nitrobenzene and carbon monoxide are reacted in the presence of hydrogen using a ruthenium complex catalyst, N,N
'-Diphenylurea is obtained, but the reaction rate is slow and a large amount of aniline is inevitably produced as a by-product.

Furthermore, JP-A Nos. 62-111960 and 62-11
No. 1958, when nitrobenzene is used as an aniline solvent and carbon monoxide is reacted with a ruthenium complex catalyst, N
, N'-diphenylurea is obtained. However, in this reaction, there is a possibility that the ruthenium complex catalyst precipitates during the post-treatment process and exits the system together with the crystals of the urea compound that is the product.

Further, in Japanese Patent Application No. 63-012018, although catalyst precipitation is suppressed by the addition of a solvent, no increase in the reaction rate is observed due to the addition of the solvent.

[Problem to be solved by the invention] The present invention has been made in view of the above circumstances, and its purpose is to facilitate separation of the product after the reaction and the catalyst component, and to Ureas that have a high yield of ureas and can further increase the reaction rate and efficiently recycle the catalyst by using a compound that has coordination ability with the catalyst metal as part of the solvent. The purpose of this invention is to provide a method for manufacturing the same.

[Means for Solving the Problems] The present invention involves reacting an aromatic primary amine, an aromatic nitro compound, and carbon monoxide, using a catalyst mainly composed of a compound containing a platinum group metal, In addition, the present invention is a method for producing ureas in which a compound having a coordinating power toward metals is used as part of the solvent.

This method is believed to proceed according to the following reaction formula.

2ArNH2+CO -ArNHCNHAr+2 [H] +) A r NO2+ 2 CO+ 2 [H]
-a-ArNH2+2CO2 ArNH2+ArNO2+3C0 Ar N HCN HA r + 2 CO2 [H: means M-H (M: catalytic metal) Aromatic primary amines include anilines, aminonaphthalenes, aminoanthracenes, amino There are biphenyls, etc., and specific compounds include aniline, o-, m-, and p-)
Luidine, o-, m- and p-chloroaniline, α- and β-naphthylamine, 2-methyl-1-aminonaphthalene, diaminobenzene isomers, triaminobenzene isomers, aminetoluene isomers, diaminotoluene Examples include each isomer, each isomer of aminonaphthalene, and mixtures thereof.

Aromatic mononitro compounds include nitrobenzenes,
Nitronaphthalenes, nitroanthracenes, nitrobiphenyls, or at least one hydrogen substituent, such as a halogen atom, a cyano group, an alicyclic group, an aromatic group, an alkyl group, an alkoxy group, a sulfone group, a sulfoxide group, There are nitro compounds substituted with carbonyl groups, ester groups, amide groups, etc. Specific compounds include nitrobenzene, o-, m- and p-nitrotoluene, 0-nitro-p-xylene, 2-methyl-1
-Nitronaphthalene, dinitrobenzene isomers, trinitrobenzene isomers, dinitrotoluene isomers,
Examples include nitronaphthalene isomers, om-chloronitrobenzene, 1-bromo-4-nitrobenzene, and mixtures thereof. However, it is preferable to use nitro compounds corresponding to aromatic primary amines.

Examples of the coordinating amide compound to be added include amides, specifically N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidinone, etc. Substitutions represented by the general formula RI R2NCNR3R4 Urine 1; elementary compound (R1, R2, R3, R4 are alkyl groups and
alkylene containing 3 to 5 carbon atoms connected by a carbon chain) 1, specifically N, N, N', N' tetramethylurea, 1.3-dimethyl-2-imidazolidinone, 1.3
-dimethyltetrahydro-2(IH)-pyrimidinone, etc., general formula RI R2NC-(CH2). A phosphine-amide compound represented by -PPh2 (RIR2 is an alkyl group having 1 to 5 carbon atoms, and n is 1 to 5), with the general formula R' CN-CH2). Phosphine-amide compounds represented by -PPh2R2 (RIH2 is an alkyl group having 1 to 6 carbon atoms and an alkylene having 3 to 5 carbon atoms connected by a carbon chain), their isomers, and mixtures thereof etc.

Oxygen-containing organic sulfur compounds, such as sulfoxides, are represented by the general formula R1-5o-R2 or R15o2-R2. Here, R1 and R2 are alkyl containing 1 to 8 carbon atoms, substituted with alkoxy, or substituted with phenyl, and R1 and R2 are alkylene containing 4 to 7 carbon atoms connected by a carbon chain. Specific examples include dimethyl sulfoxide, diphenyl sulfoxide, and sulfolane.

In the method of the present invention, it is possible to use only the compound with coordinating power to be added as a solvent, but it is also preferable to carry out the method in a mixed solvent with other suitable solvents. Such other suitable solvents include, for example, aromatic hydrocarbons such as benzene, toluene, xylene and mesitylene, halogenated aliphatic hydrocarbons such as chlorohexane and chlorocyclohexane, chlorobenzene, bromobenzene and dichlorobenzene. , halogenated aromatic hydrocarbons such as trichlorobenzene, etc. are used.

Carbon monoxide may be pure or may contain nitrogen, argon, helium, carbon dioxide, halogenated hydrocarbons, and the like.

Compounds containing platinum group metals are compounds such as platinum group elements such as ruthenium, rhodium, palladium, and platinum, and ligands such as carbon oxide and phosphines, or organometallic compounds having an organic group. , those containing no halogen elements are preferred. Specifically, Ru3 (Co)+
2+H4Ru4 (Co)12. [Ru2, (CO
)4(HCOO)2]n, Ru
(Co) 3 (dppe).

Ru (Co) 3 (PPh3) 2 , Ru(
acac) 3 and other ruthenium complex compounds, Rh 6
(CO) +61RhH(Co)(PPh3)3, R
h(acac)(Co)(PPh3), Rh(acac
c) (Co)2.

Examples include rhodium complex compounds such as Rh (acac)3. However, PPh3 is triphenylphosphine, dppe is diphenylphosphinoethane, acac
indicates acetylacetonate.

In addition to these complex compounds, inorganic platinum group metal compounds that convert into active species in the reaction system can also be used. Specifically, Ru02nH20s Ru-black, Ru carbon, etc. are mentioned. These compounds are
It is thought that it changes into a carbonyl complex in the reaction system and provides active species.

Furthermore, cobalt, iron, rhodium, palladium, etc. can be used in combination with these platinum group metals.

The reaction temperature is usually 30-300°C, preferably 120-200°C.
It is carried out in the temperature range of 00°C. Reaction pressure is 1-500
kg/c, preferably in the range of 10 to 150 kg/c♂, and the reaction time varies depending on other conditions, but is usually from several minutes to several hours.

[Operations and Effects of the Invention] The ureas obtained by the method of this invention have low solubility in solvents and raw materials such as aromatic amines and aromatic nitro compounds. Therefore, simply by cooling the solution after the reaction to about room temperature, the produced ureas will precipitate out as crystals. Therefore, by filtering this solution, ureas can be efficiently obtained as a solid substance. On the other hand, since the catalyst is stabilized by the added coordinating solvent and exists in the filtrate without being precipitated, it can be reused as is, which is economical. After the reaction, when cooling to room temperature and crystallizing, components other than ureas in the reaction mixture can be easily separated by washing with a solvent such as toluene or benzene, and only ureas can be taken out alone.

In this reaction, compounds that do not participate in the reaction, such as toluene and cyclohexane, can also be used as part of the solvent. In addition, since increasing the concentration of aromatic primary amine increases the reaction rate, by adding a large excess of aromatic primary amine and using it as part of the solvent, the reaction can be carried out at a high reaction rate. .

In addition, in this invention method, by adding a coordinating solvent,
An increase in the reaction rate occurs and the reaction can be carried out at a higher reaction rate.

Further, in this invention, since there is no need to use a halogen compound, corrosion of equipment materials is extremely low, and there is no need to use expensive materials for the reactor.

Furthermore, this reaction has fewer side reactions and can yield ureas in high yields.

[Example] Example 1 In a magnetic stirring autoclave with an internal volume of 200 ml, 5.6 g of nitrobenzene, 7.8 g of aniline, and 2) luene were added.
7m1, N, N, N', N'-tetramethylurea (
(hereinafter abbreviated as TMU)6. 3g, Ru3(CO) 12
After adding 20 mg and replacing the system with carbon monoxide,
- Carbon oxide was press-ined at 50 kg/c+#.

The reaction was carried out at 160° C. for 2.0 hours while stirring. After the reaction is complete, cool to room temperature, evacuate, filter the reaction solution, and purify with N.
, 3.5 g of N'-diphenylurea crystals were obtained. When the filtrate was analyzed by gas chromatography and high performance liquid chromatography, it was found to contain 0.1 g of N,N'-diphenylurea and 2.9 g of nitrobenzene. From this, N.
T based on catalyst metal atom for N'-diphenylurea production
OF (Turn 0ver Frequency)
The selectivity based on 100h-+1 nitrobenzene is 94
%Met.

Example 2 Next, using the same apparatus and the same operation as shown in Example 1, the amount of TMU was 16.4 g, and the amount of toluene was 15 m
Table 1 shows the results of an experiment to produce N,N'-diphenylurea instead of Example 1.

Comparative Example 1 Using the same equipment as in Example 1 and using the same operation, TMU was not added and the amount of toluene was changed to 32 ml.
Table 1 shows the results of an experiment for producing N,N'-diphenylurea.

Comparative Example 2 In the same apparatus and the same operation as shown in Example 1, pyridine was added instead of TMU, and N, N'-
Table 1 shows the results of the diphenyl urea production experiment.

Comparative Example 3 In the same apparatus and the same operation as shown in Example 1, benzonitrile was added instead of TMU, and N,N
Table 1 shows the results of the experiment for producing '-diphenylurea.

Examples 3 to 8 Table 2 shows the results of N,N'-diphenylurea production experiments conducted using the same apparatus and the same operation as shown in Example 1, but with different coordinating solvents added. .

Example 9 In the same apparatus and in the same operation as shown in Example 1, the catalyst used was [Ru2(Co)4(HCOO)2
Table 3 shows the results of a production experiment of N,N'-diphenylurea instead of 1n.

Procedural amendment 1989 10. , i3 Lord Wen Yi

Claims (2)

[Claims] (1) When producing ureas by reacting aromatic primary amines, aromatic nitro compounds, and carbon monoxide, a catalyst mainly containing compounds containing platinum group metals is used, and those metals are A method for producing ureas that uses an amide compound or an oxygen-containing sulfur compound with coordinating power as part of the solvent or as a ligand. (2) A method for producing ureas according to claim 1, which does not use a halogen compound.