U.S. patent number RE34,137 [Application Number 07/420,364] was granted by the patent office on 1992-12-01 for method of manufacturing aromatic urethane and intermediate product thereof.
This patent grant is currently assigned to NKK Corporation. Invention is credited to Takao Ikariya, Masanori Itagaki, Masatsugu Mizuguchi, Itaru Sakai, Osamu Tajima.
United States Patent |
RE34,137 |
Ikariya , et al. |
December 1, 1992 |
Method of manufacturing aromatic urethane and intermediate product
thereof
Abstract
The present invention relates to a method of manufacturing
aromatic urethane, an aromatic mononitro-compound, an aromatic
primary amine, and carbon monoxide being reacted using a catalyst
containing a platinum group metal-containing compound as a major
constituent to prepare N,N'-di-substituted urea. The resultant
N,N'-di-substituted urea is reacted with a hydroxyl
group-containing organic compound to prepare an aromatic primary
amine and aromatic urethane, and the aromatic primary amine is
separated to obtain aromatic urethane.
Inventors: |
Ikariya; Takao (Tokyo,
JP), Itagaki; Masanori (Yokohama, JP),
Mizuguchi; Masatsugu (Kawasaki, JP), Sakai; Itaru
(Yokohama, JP), Tajima; Osamu (Kamakura,
JP) |
Assignee: |
NKK Corporation (Tokyo,
JP)
|
Family
ID: |
27529122 |
Appl.
No.: |
07/420,364 |
Filed: |
October 12, 1989 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
902527 |
Sep 2, 1986 |
04678856 |
Jul 7, 1987 |
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Foreign Application Priority Data
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Sep 4, 1985 [JP] |
|
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60-195306 |
Sep 4, 1985 [JP] |
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60-195307 |
Sep 4, 1985 [JP] |
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60-195308 |
Nov 8, 1985 [JP] |
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60-250497 |
Nov 8, 1985 [JP] |
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60-250499 |
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Current U.S.
Class: |
560/24; 546/55;
546/309; 560/25; 560/27; 560/30; 560/32; 564/48; 546/48; 560/28;
560/12; 546/308; 560/31; 564/55; 560/48 |
Current CPC
Class: |
C07C
273/1809 (20130101) |
Current International
Class: |
C07C
273/00 (20060101); C07C 273/18 (20060101); C07C
125/065 (); C07C 125/067 (); C07C 125/073 (); C07C
125/075 () |
Field of
Search: |
;560/24,12,27,28,30,31,32 ;546/48,55,308,309 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lone; Werren B.
Attorney, Agent or Firm: Frishauf, Holtz, Goodman &
Woodward
Claims
What is claimed is:
1. A method of manufacturing aromatic urethane, comprising:
the urea producing step of reacting an aromatic mononitro-compound,
an aromatic primary amine, and carbon monoxide by using a catalyst
having a platinum group metal-containing compound as a major
constituent to prepare N,N'-di-substituted urea and of separating
and recovering the resultant N,N'-di-substituted urea from a
reaction solution.Iadd., said aromatic primary amine being in an
excessive amount to function as a solvent and said reaction is in
the absence of halogen or a halogen compound.Iaddend.;
the step of reacting the N,N'-di-substituted urea as an
intermediate product prepared in the urea producing step with an
organic compound containing a hydroxyl group to prepare an aromatic
primary amine and aromatic urethane, and of separating the aromatic
primary amine from the aromatic urethane, thereby obtaining the
aromatic urethane; and
the step of recirculating the separated aromatic primary amine
.[.in the.]. .Iadd.to said .Iaddend.urea producing step.
2. A method according to claim 1, wherein the platinum group
metal-containing compound is a rhodium complex compound.
3. A method according to claim 1, wherein the platinum group
metal-containing compound is a ruthenium complex compound.
4. A method according to claim 1, wherein the N,N'-di-substituted
urea reacts with the hydroxyl group-containing organic compound
without using a catalyst. .[.5. A method according to claim 1,
wherein the aromatic primary amine is added in an excessive amount
so as to use the aromatic primary amine as a solvent..]. .[.6. A
method of manufacturing ureas by reacting an aromatic primary
amine, an aromatic nitro-compound, and carbon monoxide by using a
catalyst essentially consisting of a platinum group
metal-containing compound..]. .[.7. A method according to claim 6,
wherein the platinum group metal-containing compound is a rhodium
complex compound..]. .[.8. A method according to claim 6, wherein
the platinum group metal-containing compound is a ruthenium complex
compound..]. .[.9. A method according to claim 6, wherein the
aromatic primary amine is used in an excessive amount to use the
aromatic primary amine as a solvent..].
.Iadd.10. A method according to claim 1 wherein said catalyst is
selected from the group consisting of Ru.sub.3 (CO).sub.12, H.sub.4
Ru.sub.4 (CO).sub.12, Ru(CO).sub.3 (PPh.sub.3).sub.2, Ru(CO).sub.3
(dppe), (Ru(CO).sub.2 (HCO).sub.2 P(C-C.sub.6
H.sub.11).sub.3).sub.2, Ru(acac).sub.3, Rh.sub.6 (CO).sub.16,
RhH(CO)(PPh.sub.3).sub.3, (Rh(acac)(CO)(PPh.sub.3),
Rh(acac)(CO).sub.2, and Rh(acac).sub.3, wherein dppe represents
diphenylphosphinoethane and acac represents
acetylacetonato..Iaddend. .Iadd.11. A method according to claim 1
wherein said catalyst is selected from the group consisting of
Ru.sub.3 (CO).sub.12, H.sub.4 Ru.sub.4 (CO).sub.12, Ru(CO).sub.3
(PPh.sub.3).sub.2, Ru(CO).sub.3 (dppe), (Ru(CO).sub.2 (HCO).sub.2
P(C-C.sub.6 H.sub.11).sub.3).sub.2, and Ru(acac).sub.3, wherein
dppe represents diphenylphosphinoethane and acac represents
acetylacetonato..Iaddend. .Iadd.12. A method according to claim 1,
wherein said aromatic mononitro-compound corresponds to said
aromatic primary amine..Iaddend. .Iadd.13. A method according to
claim 1, wherein said aromatic primary amine is aniline..Iaddend.
.Iadd.14. A method according to claim 1, wherein said aromatic
primary amine is aniline; and said aromatic mononitro-compound is
nitrobenzene..Iaddend. .Iadd.15. A method according to claim 10,
wherein said aromatic mononitro-compound corresponds to said
aromatic primary amine..Iaddend. .Iadd.16. A method according to
claim 2, wherein said aromatic primary amine is aniline; and said
aromatic mononitro-compound is nitrobenzene..Iaddend. .Iadd.17. A
method according to claim 3, wherein said aromatic primary amine is
aniline; and said aromatic mononitro-compound is
nitrobenzene..Iaddend. .Iadd.18. A method according to claim 10,
wherein said aromatic primary amine is aniline; and said aromatic
mononitro-compound is nitrobenzene..Iaddend. .Iadd.19. A method
according to claim 11, wherein said aromatic primary amine is
aniline; and said aromatic mononitro-compound is
nitrobenzene..Iaddend. .Iadd.20. A method according to claim 1
wherein said urea producing step is carried out in a first reactor
and said step of producing the aromatic urethane is carried out in
a second reactor.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing aromatic
urethane.
2. Description of the Prior Art
Various conventional methods of manufacturing aromatic urethane
have been proposed. These methods are classified into a method
using an aromatic nitro-compound as a starting material and a
method using an aromatic primary amine as a starting material.
According to the conventional method using an aromatic
nitro-compound as a starting material, an aromatic nitro-compound
(e.g., nitrobenzene), an organic compound (e.g., an alcohol)
containing a hydroxyl group, and carbon monoxide are allowed to
react reductively with each other in the presence of a catalyst
having a platinum group compound such as a palladium or rhodium
compound as a major constituent to manufacture aromatic urethane.
Examples of this method are described in Japanese Patent Disclosure
(Kokai) Nos. 51-98240 and 54-22339 and Japanese Patent Publication
No. 43-23939.
According to the conventional method using an aromatic primary
amine as a starting material, aromatic primary amine (e.g.,
aniline), an organic compound (e.g., an alcohol) containing a
hydroxyl group, and carbon monoxide are allowed to react
oxidatively with each other in the presence of an oxidizer such as
oxygen or an organic nitro-compound through a catalyst containing a
platinum group metal compound such as a palladium or rhodium
compound to prepare aromatic urethane. Examples of this method are
described, e.g., in Japanese Patent Disclosure (Kokai) Nos.
55-124750, 55-120551, and 59-172451.
In either method, since use of only a platinum group metal compound
as the major constituent of the catalyst results in low synthetic
activity of urethane, a halogen compound such as iron chloride,
iron oxychloride, vanadium oxychloride, or potassium iodide is used
as an assistant catalyst. A mixture of the platinum group metal
compound and the assistant catalyst are dissolved in a reacting
system. However, the halogen compound greatly corrodes a metal
material such as a reaction chamber and piping valves. For this
reason, an expensive metal material having a good anticorrosion
property must be used.
When a platinum group metal compound as a main catalyst is
dissolved in a reaction solution or a solid platinum group metal
compound is used, the platinum group metal partially contains a
halogen compound and the halogen compound is eluted in the reaction
solution. In order to recover the platinum group metal compound
from the reaction solution at the end of reaction, cumbersome
operations and high cost are required.
In addition, an organic compound containing a hydroxyl group for a
reaction material is used as a reaction solution, and aromatic
urethane has high solubility in the organic compound containing a
hydroxyl group. For this reason, in order to crystallize and
separate aromatic urethane from the solution after reaction, the
solution must be cooled to an extremely low temperature of several
tens of minus degrees in centigrade. Alternatively, the solution
must be condensed and cooled to allow precipitation of crystals.
Even if such precipitation is performed, it is difficult to recover
aromatic urethane dissolved in the solution separately from the
catalyst. Another method of recovering aromatic urethane is a
distallation method. In this case, however, since the dissolved
catalyst must be recovered as a distillation residue, aromatic
urethane must be distilled. However, aromatic urethane is a
compound having a high boiling point and must be distilled at a
temperature of 100.degree. to 150.degree. C. under a high vacuum of
about 1 mmHg.
Furthermore, if an aromatic nitro-compound is used as a starting
material, a small amount of nonreacted aromatic nitro-compound is
left in the reaction solution. If distillation is performed in this
state, aromatic urethane is colored in brown by the aromatic
nitro-compound.
As described above, it is difficult to separate and recover
aromatic urethane from the solution and further recover the
catalyst for reuse regardless of a recovery method, i.e.,
crystallization or distillation.
If an aromatic nitro-compound is used as a starting material an
aromatic amine is by-produced, and if an aromatic primary amine is
used as a starting material, N,N'-di-substituted urea is
by-produced, thereby decreasing the yield of aromatic urethane.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of
manufacturing aromatic urethane to solve various conventional
problems without using a halogen compound as an assistant catalyst,
to prepare aromatic urethane according to a two-step reaction, to
increase the yield of intermediate product and aromatic urethane
and to easily recover the catalyst and the resultant aromatic
urethane.
In order to achieve the above object of the present invention,
there is provided a method of manufacturing aromatic urethane,
comprising:
the urea producing step of reacting an aromatic mononitro-compound,
an aromatic primary amine, and carbon monoxide by using a catalyst
having a platinum group metal-containing compound as a major
constituent to prepare N,N'-di-substituted urea and of separating
and recovering the resultant N,N'-di-substituted urea from a
reaction solution;
the step of reacting the N,N'-di-substituted urea as an
intermediate product prepared in the urea producing step with an
organic compound containing a hydroxyl group to prepare an aromatic
primary amine and aromatic urethane, and of separating the aromatic
primary amine from the aromatic urethane, thereby obtaining the
aromatic urethane; and
the step of recirculating the separated aromatic primary amine in
the urea producing step.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An aromatic mononitro-compound, aromatic primary amine, and carbon
monoxide are reacted using a catalyst using a ruthenium complex
compound as a major constituent.
This reaction progresses according to the following general
formula: ##STR1##
The aromatic primary amine comprises anilines, aminonaphthalenes,
aminoanthracenes, amonobiphenyls, and the like. Examples of these
aromatic primary amine are aniline, o-, m- and p-toluidine, o- m-
and p-chloroaniline, .alpha.- and .beta.-naphthylamine
2-methyl-1-aminonaphthalene, diaminobenzene, triaminobenzene,
aminotoluene, diaminotoluene, aminopyridine, diaminopyridine,
aminonaphthalene, diaminonaphthalene, an isomer thereof, and a
mixture thereof.
An aromatic mononitro-compound comprises nitrobenzenes,
nitronaphthalenes, nitroanthracenes, nitrobiphenyls, and a
nitro-compound wherein at least one hydrogen atom is substituted
with another substituent (e.g., a halogen atom, a cyano group, an
alicyclic group, an aromatic group, an alkyl group, an alkoxyl
group, a sulfoxide group, a sulfone group, a carbonyl group, an
ester group, and an amide group). Examples of these aromatic
mononitro-compound are nitrobenzene, o-, m-, and p-nitrotoluene,
o-nitro-p-xylene, 2-methyl-1-nitronaphthalene, o-, m- and
p-chloronitrobenzene, 1-bromo-4-nitrobenzene, an isomer thereof,
and a mixture thereof. It should be noted that a nitro-compound
corresponding to the selected aromatic primary amine is
preferable.
Carbon monoxide may be pure carbon monoxide, or may be mixed with
nitrogen, argon, helium, carbon dioxide gas, hydrocarbon, or
halogenated hydrocarbon.
A platinum group metal-containing compound is a compound of a
platinum group metal (e.g., ruthenium, rhodium, palladium, and
platinum) and an organometallic compound having a ligand (e.g.,
carbon monoxide and a phosphine) or an organic group). In this
case, the platinum group metal-containing compound preferably does
not contain a halogen atom. Preferred examples of such a compound
are a ruthenium complex compound such as Ru.sub.3 (CO).sub.12,
H.sub.4 Ru.sub.4 (CO).sub.12, Ru(CO).sub.3 (PPh.sub.3).sub.2,
Ru(CO).sub.3 (dppe), (Ru(CO).sub.2 (HCO).sub.2 P(C-C.sub.6
H.sub.11).sub.2, and Ru(acac).sub.3, and a rhodium complex compound
such as Rh.sub.6 (CO).sub.16, RhH(CO)(PPh.sub.3).sub.3,
Rh(acac)(CO)(PPh.sub.3), Rh(acac)(CO).sub.2, and Rh)acac).sub.3,
wherein dppe represents diphenylphosphinoethane and acac represents
acetylacetonato.
Cobalt, iron, rhodium, palladium, or the like is combined with a
platinum group metal compound.
When a ruthenium complex compound is used as a major constituent of
a catalyst, a reaction temperature generally falls within the range
of 30.degree. to 300.degree. C. and preferably 120.degree. to
200.degree. C. A reaction pressure generally falls within the range
of 1 to 500 kg/cm.sup.2 and preferably 10 to 300 kg/cm.sup.2.
When a rhodium complex compound is used as a major constituent of a
catalyst, a reastion temperature generally falls within the range
of 80.degree. to 300.degree. C. and preferably 120.degree. to
200.degree. C.
A reaction pressure generally falls with the range of 1 to 500
kg/cm.sup.2 and preferably 20 to 300 kg/cm.sup.2. The reaction time
varies according to other conditions but generally falls within the
range of 0.5 to 24 hours.
The reaction can be achieved without using a solvent. However, a
proper solvent such as an aromatic hydrocarbon (e.g., benzene,
toluene, xylene, and cyclohexane) may be used. When the
concentration of aromatic primary amine as a starting material is
increased, the reaction rate is increased. Therefore, an aromatic
primary amine is used in an excessive amount and can be
substantially used as a solvent, thereby achieving the reaction at
a maximum rate.
The resultant N,N'-di-substituted urea has low solubility with
respect to the solvent. For this reason, the solution after the
reaction is simply cooled to precipitate N,N'-di-substituted urea
as crystals. Therefore, the resultant solution is filtered to
obtain solid N,N'-di-substituted urea. The catalyst is obtained as
a solution together with the solvent. The solvent containing the
catalyst can be used again.
The organic compound containing N,N'-di-substituted urea and a
hydroxyl group reacts according to the following formula to prepare
aromatic primary amine and aromatic urethane. ##STR2##
The organic compound containing a hydroxyl group comprises
monoalcohols and monophenols. Examples of such a compound are
monoalcohols (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl,
and t-butyl) and alkyl phenols (e.g., phenol, chlorophenol, and
methyl, ehtyl, n-propyl, and isopropyl substituted phenol).
The reaction temperature generally falls within the range of
80.degree. to 300.degree. C. and preferably 120.degree. to
200.degree. C. The reaction pressure is a pressure naturally
obtained at a reaction temperature of the hydroxyl group-containing
organic compound or solvent.
The reaction time varies according to other conditions but
generally falls within the range of 1 to 10 hours.
This reaction can be achieved without using a catalyst.
After the end of reaction, distillation is performed to recover
aromatic urethane as a distillation residue. On the other hand,
aromatic primary amine is recovered by distillation. Aromatic
primary amine is used again in the production of
N,N'-di-substituted urea in the first-step reaction.
According to the present invention, since N,N'-di-substituted urea
produced in the first-step reaction has low solubility in the
solvent, it can be easily crystallized, and N,N'-di-substituted
urea can be effectively recovered by filtration. In addition, the
catalyst is contained together with the solvent in the filtered
solution. The catalyst can be reused in the first-step
reaction.
The catalyst contains a compound containing a platinum group metal
as a major constituent. A halogen compound need not be used. For
this reason, the metal members required for the reaction are little
corroded, and an expensive material need not be used.
The first-step reaction is free from a side reaction and can
produce N,N'-di-substituted urea at a high yield.
An excessive amount of aromatic primary amine is added in the urea
production reaction, and aromatic primary amine is used as a
solvent to increase the reaction rate.
In the second-step reaction, the catalyst need not be used.
Aromatic urethane is not eluted and can be recovered as a
distillation residue. Aromatic primary amine as a distilled
material and the compound containing a residual hydroxyl group have
relatively low boiling points. Therefore, distillation can be
performed at moderate conditions, thus simplifying the operations.
In addition, the recovered aromatic primary amine can be reused in
the first-step reaction. The second-step reaction results in little
side reaction in the same manner as in the first-step reaction.
Therefore, aromatic urethane can be prepared in the two-step
reaction at a high yield.
EXAMPLES
The present invention will be described in detail by way of
examples. In the following examples, term "alkyl carbamate" is used
instead of term "urethane", and the individual material names are
indicated.
EXAMPLE 1
3.82 g of nitrobenzene, 2.85 g of aniline, 34.58 g of toluene, and
0.10 g of Ru.sub.3 (CO).sub.12 were charged in an electromagnetic
stirring type autoclave having an inner volume of 200 ml. Carbon
monoxide was supplied to the autoclave at a pressure of 50
kg/cm.sup.2. The materials were stirred and reacted at a
temperature of 160.degree. C. for 6 hours. After the reaction, the
mixture was cooled to room temperature. The autoclave was then
evacuated, and the reaction solution was filtered to obtain 5.91 g
of crystals. The crystals were analyzed by liquid chromatography
and found to have a 90% yield of N,N'-diphenyl urea for
nitrobenzene. In addition, the reactive filtered solution
containing the catalyst after the separation of N,N'-diphenyl urea
was used to repeat the above test under identical conditions. The
yield of N,N'-diphenyl urea was 90%.
3.00 g of the resultant crystals and 50.00 g of methyl alcohol were
filled in another electromagnetic stirring type autoclave having an
inner volume of 200 ml and were stirred and reacted at a
temperature of 160.degree. C. for 3 hours. When the reacted
solution was analyzed, it had a 94% yield for N-phenylmethyl
carbamate and a 95% yield for aniline.
EXAMPLE 2
Following the dame procedures as in Example 1 except that 0.13 g of
Ru.sub.3 (CO).sub.12 was used as the catalyst, nitrobenzene,
aniline and carbon monoxide were reacted to prepare 5.94 g of
N,N'-diphenyl urea crystals. The yield of N,N'-diphenyl urea for
nitrobenzene was 94%.
Following the same procedures as in Example 1, 3.00 g of the
crystals and 50.00 g of ethyl alcohol were reacted to obtain a 93%
yield for N-phenylethyl carbamate and a 95% yield for aniline.
EXAMPLE 3
Following the same procedures as in Example 1 except that 0.31 g of
Ru(CO).sub.3 (PPh.sub.3).sub.2 was used in place of Ru.sub.3
(CO).sub.12 as the catalyst, nitrobenzene, aniline and carbon
monoxide were reacted to prepare 5.77 g of N,N'-diphenyl urea
crystal. The yield of N,N'-diphenyl urea for nitrobenzene was
90%.
Following the same procedures as in Example 1, 3.00 g of the
crystals and 50.00 g of ethyl alcohol were reacted to obtain a 92%
yield for N-phenylmethyl carbamate and a 93% yield for aniline.
EXAMPLE 4
Following the same procedures as in Example 1 except that 0.31 g of
Ru(acac).sub.3 was used in place of Ru.sub.3 (--CO).sub.12 as the
catalyst nitrobenzene and that the reaction time was 8 hours,
aniline and carbon monoxide were reacted to prepare 6.04 g of
N,N'-diphenyl urea crystals. The yield of N,N'-diphenyl urea for
nitrobenzene was 96%.
Following the same procedures as in Example 1, 3.00 g of the
crystals and 30.00 g of methyl alcohol were reacted to obtain a 93%
yield for N-phenylmethyl carbamate and a 92 % yield for
aniline.
EXAMPLE 5
3.77 g of nitrobenzene, 2.78 g of aniline, 34.03 g of toluene, 0.38
g of Rh.sub.6 (CO).sub.16, and 1.24 g of triphenylphosphine were
charged in an electromagnetic stirring type autoclave having an
inner volume of 200 ml. Carbon monoxide was supplied to the
autoclave at a pressure of 50 kg/cm.sup.2. The materials were
stirred and reacted at a temperature of 160.degree. C. for 9 hours.
After the reaction, the mixture was cooled to room temperature. The
autoclave was then evacuated, and the reaction solution was
filtered to obtain 6.05 g of crystals. The crystals were analyzed
by liquid chromatography and found to have a 93% yield for
N,N'-diphenyl urea based on nitrobenzene.
300 g of the resultant crystals and 50.00 g of methyl alcohol were
filled in another electromagnetic stirring type autoclave having an
inner volume of 200 ml and were stirred and reacted at a
temperature of 160.degree. C. for 3 hours. When the reaction
mixture was analyzed, it had a 93% yield for N-phenylmethyl
carbamate and a 94% yield for aniline.
EXAMPLE 6
Following the same procedures as in Example 5 except that 0.30 g of
Rh.sub.4 (CO).sub.12 was used as the catalyst nitrobenzene and the
reaction time was 10 hours, nitrobenzene, aniline and carbon
monoxide were reacted to prepare 5.76 g of N,N'-diphenyl urea
crystal. The yield of N,N'-diphenyl urea based on nitrobenzene was
95%.
Following the same procedures as in Example 5, 3.00 g of the
crystals and 50.00 g of ethyl alcohol were reacted to obtain a 93%
yield for N-phenylethyl carbamate and a 95% yield for aniline.
EXAMPLE 7
Following the same procedures as in Example 5 except that 0.38 g of
Rh.sub.6 (CO).sub.16 was used as the catalyst and
triphenylphosphine was not added, nitrobenzene, aniline and carbon
monoxide were reacted to prepare 1.16 g of N,N'-diphenyl urea
crystals. The resultant crystals and the solution were analyzed to
obtain a nitro benzene conversion of 20% and a 93% selectivity for
converted nitrobenzene.
Following the same procedures as in Example 5, 1.00 g of the
crystals and 20.00 g of methyl alcohol were reacted to obtain a 92%
yield for N-phenylmethyl carbamate and a 93% yield for aniline.
EXAMPLE 8
3.71 g of nitrobenzene, 40.0 ml of aniline, and 0.0509 g of
Ru.sub.3 (CO).sub.12 were charged in an electromagnetic stirring
type autoclave having an inner volume of 200 ml. Carbon monoxide
was supplied to the autoclave at a pressure of 50 kg/cm.sup.2. The
materials were stirred and reacted at a temperature of 160.degree.
C. for 1.5 hours. After the reaction, the mixture was cooled to
room temperature. The autoclave was then evacuated, and the
reaction solution was filtered to obtain 5.42 g of crystals. The
filtered solution was analyzed by liquid chromatography and found
to contain 0.37 g of N,N'-diphenyl urea. However, no nitrobenzene
was detected.
The yield of N,N'-diphenyl urea separated from the solution was
85%. If N,N'-diphenyl urea contained in the solution was included,
a total yield thereof was 91%. A turn over rate of the catalyst was
84 (mol-PhNo.sub.2 /mol-Ru.hr).
3.00 g of the singly separated N,N'-diphenyl urea and 50.00 g of
methyl alcohol were filled in another electromagnetic stirring
autoclave having an inner volume of 200 ml and were stirred and
reacted at a temperature of 160.degree. C. for 3 hours. After the
reaction, the solution was analyzed to result in a 94% yield for
N-phenylmethyl carbamate and a 95% yield for aniline.
EXAMPLES 9 TO 12
Following the same procedures and apparatus as in Example 8, the
production test of N,N'-diphenyl urea was performed. The obtained
results are summarized in Table 1 below.
TABLE 1
__________________________________________________________________________
Reaction Starting Material Reaction Reaction Time Pressure Example
Nitrobenzene (g) Aniline (ml) Ru.sub.3 (CO).sub.12 (g) Temperature
(.degree.C.) (hr) (kg/cm.sup.2)
__________________________________________________________________________
9 7.41 40.0 0.0202 180 1.5 50 10 3.73 40.0 0.0500 160 2.0 30 11
2.49 40.0 0.1000 160 2.0 10 12 2.45 40.0 0.1000 140 2.0 50
__________________________________________________________________________
N,N'-diphenyl Solution After Reaction N,N'-diphenyl Nitrobenzene
Urea Selec- Turn Over Rate Nitrobenzene N,N'-diphenyl Urea Crystal
Conversion tivity Coef- (mol-PhNO.sub.2 / Example (g) Urea (g) (g)
Rate (%) ficient (%) mol-Ru .multidot. hr)
__________________________________________________________________________
9 1.87 0.35 8.67 75 94 316 10 0 0.40 5.18 100 87 .gtoreq.65 11 0
0.36 3.05 100 80 .gtoreq.22 12 0 0.41 3.49 100 93 .gtoreq.21
__________________________________________________________________________
EXAMPLE 13
The same procedures as in Example 8 were followed except that the
starting materials were 1.08 g of nitrobenzene, 40.0 ml of aniline,
and 0.0800 g of Ru(acac).sub.3, the reaction temperature was
160.degree. C., 50 kg/cm.sup.2 of CO were supplied, and the
reaction time was 2.0 hours. As a result, 2.80 g of crystals were
obtained. Nitrobenzene was not detected in the filtered solution by
0.27 g of N,N'-diphenyl urea was contained therein.
The yield of the singly separated N,N'-diphenyl urea was 90%. If
N,N'-diphenyl urea contained in the solution was included, a total
yield was 99%. A turn over rate of the catalyst was 36
mol-PhNo.sub.2 /mol-Ru.hr).
Following the same procedures as in Example 8, a total amount of
N,N'-diphenyl urea crystal was reacted with 50.00 g of ethyl
alcohol. After the reaction, the reaction mixture was analyzed to
obtain a 93% yield for N-phenylethyl carbamate and a 95% yield for
aniline.
EXAMPLE 16
The same procedures as in Example 8 were followed except that the
starting materials were 2.32 g of nitrobenzene, 40.0 ml of aniline,
and 0.0817 g of Ru(--CO).sub.3 (PPh.sub.3).sub.2, the reaction
temperature was 160.degree. C., 50 kg/cm.sup.2 of CO were supplied,
and the reaction time was 1.5 hours. As a result, 3.38 g of
crystals were obtained. Nitrobenzene was not detected in the
filtered solution but 0.31 g of N,N'-diphenyl urea was contained
therein.
The yield of the singly separated N,N'-diphenyl urea was 85%. If
N,N'-diphenyl urea contained in the solution was included, a total
yield was 93%. A turn over rate of the catalyst was 109
(mol-PhNo.sub.2 /mol-Ru.hr).
Following the same procedures as in Example 8, 3.00 g of
N,N'-diphenyl urea crystals were reacted with 50.00 g of methyl
alcohol. After the reaction, the reaction mixture was analyzed to
obtain a 93% yield for N-phenylethyl carbamate and a 94% yield for
aniline.
COMPARATIVE EXAMPLE 1
6.12 g of nitrobenzene, 37.00 g of methanol, and 0.11 g of Ru.sub.3
(CO).sub.12 were filled in an electromagnetic stirring type
autoclave having an inner volume of 200 ml. Carbon monoxide was
supplied to the autoclave at a pressure of 50 kg/cm.sup.2 so as to
obtain a CO atmosphere. The starting materials were stirred and
reacted at a temperature of 160.degree. C. for five hours. After
the reaction, the solution was analyzed by liquid cromatography and
found to have a nitrobenzene conversion rate of 32%. The conversion
rate of N-phenylmethyl carbamate was as low as 13%, and the
conversion rate of by-produced aniline was 40%. In other words, the
yield of N-phenylmethyl carbamate was 4%, and the yield of aniline
was 13%.
COMPARATIVE EXAMPLE 2
4.63 g of aniline, 6.12 g of nitrobenzene, 37.00 g of methanol, and
0.11 g of Ru.sub.3 (CO).sub.12 were filled in an electromagnetic
stirring type autoclave having an inner volume of 200 ml. Carbon
monoxide was supplied to the autoclave at a pressure of 50
kg/cm.sup.2 so as to obtain a CO atmosphere. The starting materials
were stirred and reacted at a temperature of 160.degree. C. for
five hours. After the reaction, the solution was analyzed by liquid
cromatography and found to have a 61% yield for N-phenylmethyl
carbamate and a 4% yield for N,N'-diphenyl urea.
The resultant solution was placed in a -5.degree. C. refrigerator
for 24 hours, but no crystals were precipitated.
COMPARATIVE EXAMPLE 3
3.82 g of nitrobenzene, 2.85 g of aniline, 34.58 g of toluene, and
0.10 g of Ru.sub.3 (CO).sub.12 were filled in an electromagnetic
stirring type autoclave having an inner volume of 200 ml. Carbon
monoxide was filled at a pressure of 50 kg/cm.sup.2 to obtain a CO
atmosphere in the autoclave. The starting materials were stirred
and reacted at a temperature of 160.degree. C. for six hours. After
the reaction, the solution was cooled to room temperature, and the
reacted solution after the autoclave was evacuated was filtered to
obtain 5.91 g of N,N'-diphenyl urea. The filtered solution was
analyzed by liquid chromatography. No nitrobenzene was detected.
The yield of the singly separated N,N'-diphenyl urea was 90%, and a
turn over rate of the catalyst was 11 (mol-PhNO.sub.2
/mol-Ru.hr).
300 g of the resultant crystals and 50.00 g of methyl alcohol were
filled in another electromagnetic stirring type autoclave having an
inner volume of 200 ml. The starting materials were stirred and
reacted at a temperature of 160.degree. C. for three hours. After
the reaction, the reaction mixture was analyzed and found to have a
94% yield for N-phenylmethyl carbamate and a 95% yield for
aniline.
* * * * *