JPS6259253A - Production of urea - Google Patents

Abstract

PURPOSE:To obtain urea in high recovery of a catalyst and in high yield, by reacting an aromatic primary amine with an aromatic nitro compound and carbon monoxide in the presence of a catalyst consisting essentially of a platinum group metal-containing compound. CONSTITUTION:An aromatic primary amine (e.g., aniline) is reacted with an aromatic nitro compound (e.g., nitrobenzene) by the use of a catalyst consisting essentially of a platinum group-containing compound [e.g., Ru3(CO)12] to give the aimed urea. The urea has low solubility insolvents or in aromatic amines and nitro compounds. Therefor, the formed urea is precipitated as crystal only by cooling the solution after the reaction to about room temperature, the solution is filtered to efficiently give the urea as a solid substance. On the other hand, since the catalyst has been dissolved in the filtrate, it is directly usable economically. The side reactions are few and the urea can be obtained in high yield.

Description

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

[Prior art and its problems]

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. However, the method using cobalt car-nyl or silver acetate does not provide very high yield and selectivity of ureas. Furthermore, methods using sulfur or selenium generally have high yields and selectivities, but require straightforward operations to separate and recover catalyst components. The method using platinum group metal sounds is published in 1986-4112.
3. It has been proposed in Japanese Patent Application Laid-Open No. 58-144363, etc., but the maximum yield of the former is about 60 cm. In addition, in the latter case, the catalyst system is complex, containing a halodan compound and oxygen gas in addition to palladium, which is the main metal catalyst, and requires complicated operations to recover the catalyst. There is a problem in which materials must be used.

[Purpose of the invention]

This invention was made in view of the above circumstances, and its objectives are to achieve a high yield of ureas, to facilitate the separation and recovery of catalyst components, and to avoid the use of halodane compounds as co-catalysts, which are expensive. The purpose of this project is to develop a method for producing ureas that does not require the use of raw materials.

[Structure of the invention]

This invention is a method for producing ureas by reacting an aromatic primary amine, an aromatic nitro compound, and carbon monoxide using a catalyst mainly containing a compound containing a platinum group metal.

This reaction is thought to proceed according to the following general formula.

Examples of aromatic primary amines include anilines, aminonaphthalenes, aminoanthracenes, aminopyphenyls, etc. Specific compounds include aniline, 6-Hm
-1 and p-toluidine.

0-g m-, and p-chloroaniline, α and β
naphthylamine, 2-methyl-1-aminonaphthalene,
Mention may be made of diaminobenzene, triaminobenzene, aminetoluene, diaminotoluene, aminopyridine, diaminopyridine, aminenaphthalene, cyaminonaphthalene and isomers thereof as well as mixtures thereof.

Aromatic mononitro compounds include nitrobenzenes,
Nitronaphthalenes, nidotetraanthracenes, nitropiphenyls, or at least one hydrogen substituent, such as a halogen atom, a cyano group, an alicyclic group, an aromatic group,
Nitro compounds in which aralkyl group, alkoxy group, sulfoxide group, sulfone group, carbonyl group, ester group, adendo group, etc. are substituted.Specific compounds include nidotetrabenzene, (1-1 !El-1 and p
-Nitrotoluene, 0-nitro-p-xylene, 2-methyl-1-nitronaphthalene% o-, m-, and p-
Examples include chloronitrobenzene, 1-promo-4-nido-tetrabenzene, isomers thereof, and mixtures thereof. However, it is preferable to use nitro compounds corresponding to aromatic primary amines.

- Carbon oxide may be pure or may contain nitrogen, aldine, helium, carbon dioxide, hydrocarbons, halogenated hydrocarbons, etc.

A compound containing a platinum group metal is a compound of a platinum group element such as ruthenium, rhodium, palladium, or platinum, and an organometallic compound having a ligand or an organic group such as carbon oxide or phosphines. It is desirable that the material does not contain halodan elements. Specifically, Ru (Co), HR
u (Co).

Ru(Co)3(PPh,)2. Ru(Co)3(d
ppe)2.

(Ru(Co)2(FICO2)P(C-CoHll)
3) Ruthenium complex compounds such as 2, Ru(aeae)5, Rh6(Co)16 *RhH(Co)(PPh
), Rh(acac)(Co)(PPh3)
.

Rh(acac)(Co)2 + Rh(acac)5
Examples include rhodium complex compounds such as. However, d
pp. represents diphenylphosphinoethane, and acac represents acetylacetonate.

Further, cobalt, iron, rhodium, fragilam, etc. can be used in combination with these platinum group metal compounds.

The reaction temperature is usually 30-300°C, preferably 120-200°C.
It is carried out in a temperature range of 0'0°C. Reaction pressure is 1-50
0kl! /cm”, preferably 10-150 kg
, /+y+", and the reaction time is 1 depending on other conditions.
-> Although it varies, it usually takes several minutes to several hours.

Although this reaction can be carried out without using a solvent, it is preferably carried out in a suitable solvent, for example an aromatic hydrocarbon such as benzene, toluene or xylene.

〔Effect of the invention〕

The ureas obtained by this method have low solubility in solvents, aromatic amines, and 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, shiureas can be efficiently obtained as a solid substance. On the other hand, since the catalyst is dissolved in the F liquid, it can be reused as it is, which is economical.

Furthermore, since there is no need to use a halodane compound, corrosion of the material is extremely low and there is no need to use expensive materials.

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

〔Example〕

Example 1 Nitrobenzene 3.82F, aniline 2.85111) Lezy3
4.581, Ru, (Co), 2o, 181 is added and after replacing the system with carbon monoxide, -carbon oxide f 50
The reaction was carried out at 160°C for 6 hours while stirring. After the reaction was completed, the reaction solution was cooled to room temperature, and after exhausting, the reaction solution was filtered to obtain crystals 5.91.9. The crystals were analyzed by liquid chromatography and the yield of N,N'-diphenylurea was 90% based on nitrobenzene.

Furthermore, when repeated tests were conducted under the same reaction conditions as above using the reaction tear fluid containing the catalyst after product separation, N
, the yield of N'-diphenylurea was 90%.

Example 2 Ru3(Co) as a catalyst, Ru(Co)3 in place of □
The same operation as in Example 1 was carried out except that 0.31.9 of (PPh3)2 was used to obtain 5.77 fi of N,N'-diphenylurea crystals. Nitrobenzene standard N,
The yield of N'-diphenylurea was 90%.

Example 3 Ru 3 (Co ) as catalyst, 2 substitutes F) K
Using 0.31g of Ru(aeac)5, the reaction time was 8.
By the same operation as in Example 1 except for the time, 9 N,
Obtained crystals of 6.04F of N'-di7-diA
It was Chi.

Example 4 Nitrobenzene 3.77 g, anisozoic acid 72.78 g, ) were placed in a magnetic stirring autoclave with an internal volume of 200 mm.
y 34.03N, Rh6(Co), 60.38 g,
Triphenylphosphine 1.241I' (il-added,
After replacing the system with carbon monoxide, 50 kg of -carbon oxide
/-3. 160'C without stirring
It reacted for 9 hours. After the reaction was completed, the reaction solution was cooled to room temperature, evacuated, and filtered to obtain crystals 6.05.9.

As a result of analyzing this crystal by liquid chromatography, the yield of N,N'-diphenylurea based on nitrobenzene was 93q6.

Comparative Example 1 Nitrobenzene 3.82II and aniline 2.85I were placed in a magnetic stirring autoclave with an internal volume of 200tnt! , instead of toluene as solvent J) 17m methanol 30.001
/, Ru5(Co), 20.1811 was added and the system was replaced with carbon monoxide, then 50 kg of -carbon oxide, /
cIn". While stirring, the temperature was 160℃.
The mixture was allowed to react for 6 hours. After the reaction was completed, the reaction solution was cooled to room temperature, evacuated, and analyzed by liquid chromatography. As a result, the yield of N,N'-diphenylurea based on aniline was 4%, and the yield of methyl N-7enylcarpamate was 61%.

Procedural amendment ffg+In (16”'j9.281:1 Director General of the Patent Office Michibe Uga 1, Indication of the case Japanese Patent Application No. 1988-195307 2, Name of the invention Process for producing ureas 3, Person making the amendment Case Relationship with Patent Applicant (412) Nippon Kokan Co., Ltd. 4, Agent 5, Voluntary Amendment 7, Contents of Amendment (1) "Aralkyl" in lines 4 to 5 of page 4 of the specification
Correct the statement to "alkyl".

(2) On page 5, line 6, “Ru(CO)s (dppe
) g J and it says “Ru(Co)s (dppe) J
I am corrected.

(3) On page 5, line 7, r P (C-Co Hl
t) Correct J to r P (C-Ca Htt ) J.

Procedural amendment ms <f", 1A"2n Director of the Patent Office Michibe Uga1, Indication of the case Japanese Patent Application No. 1988-1953072, Name of the invention Process for producing ureas 3, Person making the amendment Related Patent Applicant (412) Nippon Kokan Co., Ltd. 4, Agent 5, Spontaneous Amendment 7, Contents of the Amendment (1) In the third line from the bottom of page 3 of the central specification, the phrase “diaminonaphthalene” was replaced with “diaminonaphthalene.” correct.

(2) The second line from the bottom of the third page says "mixture".
"Mixtures, etc." is corrected.

(3) On the 5th page, line 20, the entry ノ/ml for r150 is corrected to r300Kp/7J.

(4) On page 7, line 11, the word "crystal" is corrected to "result."

Procedural Amendment Showa Part 1.9 JpO Commissioner of the Japan Patent Office Black 1) Yu Akira 1, Indication of the case Patent Application No. 1988-195307 2, Name of the invention Process for producing ureas 3, Person making the amendment Relationship with the case Patent applicant (412) Nippon Koukan Co., Ltd. 4, Agent 3-7-2 Kasumigaseki, Chiyoda-ku, Tokyo UBE Building 7 Contents of amendment (1) Page 3 of the specification, lines 4 to 7, columns 3 Correct the expression % expression % [].

(2) On page 9, line 12, "aniline standard" is corrected to "nitrobenzene standard."

−2=

Claims (1)

[Claims] A method for producing ureas by reacting an aromatic primary amine, an aromatic nitro compound, and carbon monoxide using a catalyst mainly containing a compound containing a platinum group metal.