CA1042462A - Process for the manufacture of ureas - Google Patents

Abstract

PROCESS FOR THE MANUFACTURE OF UREAS
ABSTRACT OF THE DISCLOSURE
A process for the production of ureas by con-tacting at elevated temperatures and pressures in a basic solution a nitrogenous organic compound containing at least one non-cyclic group, in which a nitrogen atom is directly attached to a single carbon atom and is also attached through a double bond to an oxygen or another nitrogen atom, with carbon monoxide and with water or another nitrogenous organic compound in which the nitrogen atom is directly attached to at least one hydrogen atom, in the presence of an active amount of a catalyst selected from the group consisting of selenium, sulfur, compounds con-taining selenium, sulfur compounds and mixtures thereof.

Description

~o~z ` B~CKGROUND OF THE INVENTION
., The presen-t invention relates to a process for the manufacture of ureas and, more particularly, to a process for the manufacture of ureas by reaction of a nitrogenous compound having a-t least one hydrogen a-tom attached -to the nitrogen or water with carbon monoxide and a nitrogenous compound in which the nitrogen is directly attached to a single carbon atom and also is attached through a double bond to an oxygen or another nitrogen under elevated temperatures and pressure conditions in a ; basic solution and in the presence of a sulfur or selenium catalyst.
Uxea and substituted ureas are important inter-mediates in the preparation of various products, particularly agricultural chemicals useful in soil treatment, as fungicides, insecticides, and germicides, in weed control ~-and other uses. For example 3-(3,4-dichlorophenyl)~
dimethylurea is a preemergenae weed control product; 1,1-dimethyl-3-phenylurea is an excellent herbicide; and 3-(p-chlorophenyl~-l,l-dimethylurea is a non-selective weed con-trol product. Thus any method which can be used to produce these and similar ureas is a valuable and useful process.
It is well known in the art to produce ureas by the reaction of an amine compound with an isocyanate or alternatively by the reaction of an amine with phosgene;
the reaction chosen is dependent upon the nature of the desired urea. 'Such processes suffer from a number of dis-advantages among whîch are the necessity for handling toxic and highly reactive compounds, the expense of the start-ing compounds and the necessi-ty of working in expensive corrosion resistant apparatus resistaht to by-produc-t .~

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hydrogen chloride genera-ted in the phosgene reaction.
; Other procedures are available; for exa~ple in U.S. Patent

2,877,268 there is described a process for preparin~ ureas by an apparently non-cataly-tic reaction of amines with car-bonyl sulfide, while British ;Patent 1,275,702 describes a catalytic process for converting amines to ureas using selenium, carbon monoxide and oxygen. It should be noted that in each of the processes it is an amine that is con-verted to a urea.
The instant invention is a simple one-step process for the preparation of ureas which eliminates the need for an isocyanate, phosgene, and in one embodiment water is used instead of an amine. Thus it is possible to start with cheaper and more readily available nitrogen-containing organic compounds.
~UMN~Y OF THE INVENTION
In accordance with the invention a ni-trogenous compound having a nitrogen atom directly attached to a single carbon atom and which is also attached through a double bond to an oxygen atom or another nitrogen atom is contacted with a nitrogenous compound having at least one hydrogen atom attached to nitrogen or with water and carbon monoxide in a basic solution at -temperatures in the range from 50C. to 2500C. under pressures in the range of from 10 atmospheres to 200 a-tmospheres in the presence of a selenium or sulfur cat~lyst or a combination thereof to produce a urea.
It is an object of -the present invention~ there-fore, to provide an improved process for the production of ureas.
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~no-ther object o-~ the present invention is to provide an efficient, one-step process for preparing ureas in high yields by reaction of a ni-trogenous compound having a nitrogen atom directly attached to a single carbon atom and which also is attached through a double bond to an oxygen atom or another nitrogen atom with water or a nitro~
genous compound in which the nitrogen atom is directly attach-ed to one or more hydrogen atoms and carbon monoxide by using catalytic amounts of selenium, sulfur, co~pounds of selenium, compounds of sulfur or any combination thereof.
~nother object of the present invention is to provide a process for the production of ureas which uses readily available, low cost starting materials.
~no-ther o~ject of the present invention is to provide a prooess for the production of ureas which does not require handling tQXiC and reactive starting materials. ~-~nother object of the present inven-tion is to provide a process for the production of ureas which does not result in the co-production of coxrosive hydrogen chloride.
These and other objects of -the invention will beoome apparent from the following description of the process and from the claims.
E~CRIPTION OF THE INVENTION
Suitable nitrogenous compounds containing at least one non-cyclic group in which the nitrogen atom is directly attached -to a single carbon atom and is also attached through a double bond -to an oxygen or another nitrogen atom typically include such compounds as organic nitro, nitroso, azo, and azoxy compounds generally containing . . ~ . . . . .

~ V4~46i2 up to 24 carbon atoms. Of these, the organic nitro com-pounds are generally preferred and -the nitro aromatic and tertiary nitroaliphatic compounds are most preferred.
Nitro compounds for use in the process inclu~e mononitro compounds such as nitrobenzene, alkyl and alkoxy nitrobenzenes wherein the alkyl group contains up to 10 carbon atoms, aryl and aryoxy nitrobenzenes, wherein the a~yl group is phenyl, tolyl, xylyl, naph-thyl, chlorophenyl, chlorotolyl, or chloronaphthyl, chloronitrobenzenes such as 4-chloronitrobenzene, 3,4-dichloronitrobenzene, dinitro-compounds such as dinitrobenzene, alkyl and al~oxy dinit~o-benzenes wherein the alkyl group contains up to 10 carbon atoms, aryl and aryloxy dinitrobenzenes wherein the aryl group is any of those mentioned above, chlorodinitrobenzenes, trinitrocompounds such as trinitrobenzene, alkyl and alkoxy-trinitrobenzenes, aryl and aryloxytrinitrobenzenes ~li~h the substituents being any of those already mentioned and chloro-trinitrobenzenes as well as similarly substituted mono and polynitro derivatives of the naphthalene, diphenyl, diphenylmethane, anthracene andpphenanthracene series as well as nitropyridines.
~rom this group of nitro compounds the aromatic nitrocompounds such as nitrobenzene, p-nitroanisole, p-nitrophenetole, p-nitrotoluene, 3,4-dichloronitrobenzene~
p-chloronitrobenzene, m-chloronitrobenzene, dinitrobenzene, dinitrotoluene~ and the ter-tiary aliphatic nitrocompounds such as 2-methyl-2-nitropropane and l-methyl-l-nitrocyclo-hexane are preferred. ~;
Examples of suitable nitrosocompounds are the aromatic nitrosocompounds such as nitrosobenzene, ni-troso-toluene and p-chloro-nitrosobenzene.

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z Suitable azo compounds have the general formula R,-N~N-R2 wherein Rl and R2 are either the same or different substi-tuted or unsubstituted alkyl or aryl groups selected from among those already listed in the descrip-tion of suitable nitrocompounds. ~zobenzene, chloroazubenzenes and alkyl or aryl substituted azo~enzenes are particularly preferred.
Suitable azoxy compounds have the general formula ` ~ , R -N=N-R
wherein R3 and R4 may be the same or different substituted or unsubstituted alkyl or aryl groups selected from among ; those already listed in the description of suitable ni-trocompounds. ~zoxybenzene, chloro-azoxybenzenes, alkyl and aryl substit~ted azobenzenes are particularly preferred.
The invention includes the use of any mixture of nitrocompounds, nitroso compounds, azo or azoxycompounds.
It is preferred to use nitrocompounds rather than nitroso, azo or azoxy compounds.
When, in the practice of this invention, any of the above-mentioned nitrogen compounds; i.e., the nitro, nitroso, azo or azoxy compounds are used as the sole reacting nitrogen compound, the resulting ureas are the symme-trical 1,3-diarylureas, 1,3-dialkylureas, or sub-stituted 1,3-diaryl or 1,3-dialkylureas. For example, when nitrobenzene is used as the only reacting nitrogen compound then carbanalide or 1,3-diphenylurea is the product.
Likewise, p-methylnitrobenzene yields 1,3-di-p-tolyurea and 3,4-dichloronitrobenzene yields 1,3-bis(3,4-dichloro-phenyl)urea.

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The process of this invention, however, is no-t limited to the production of symmetrical 1,3-dialkyl and : 1,3-diaryl ureas~ ~ddition of o-ther suitable nitrogenous compounds in which the nitrogen is attached to one or more hydrogen atoms can result in unsymmetrical 1,3-dialkyl-, 1-3-diaryl-, 1,1-diaryl-3-aryl-, 1,1-dialkyl-3-aryl-, l-alkyl-3-aryl- and 1,1-dialkyl-3-alkyl ureas. Suitable nitrogenous compounds in which the nitrogen atom is attached to one or more hydrogen atoms are generally the primary and secondary aromatic, aliphatic, aralkyl and cycloalkyl amines.
Generally, the amine group-containing compounds :
conform with one or the other of the general formula ; RlNH2; RlR2NH; R ' lN1~2, R ' lR ' 2NH; RlR ' lNH
wherein Rl and/or R2 may be the same or two different ; optionally substituted aliphatic, cycloaliphatic or arali-phatic groups, preferably con-taining from 1 to 20 carbon atoms, or R'1 and/or R'2 may be the same or two different aromatic groups containing one or more benzenoid rings and . 20 preferably not more than 3 rings which can be fused or ~oined by single valency bonds, directly or through bridging ~:
groups which can be, for example, oxygen, nitrogen or sulfur atoms or sulfoxide, sulfone, amine,amide, or carbonyl .: ~
. groups, or alkylene groups in which, if desired, the carbon chain can be interrupted by, for example, oxygen or sulfur ., .
atoms, sulfoxide, sulfone or carbonyl groups, for example, methylene, oxymethylene, dimethylene sulfone or dimethylene ketone groups. ~
The group Rl and R2 can be alkyl, cycloalkyl, :
i 30 alkylene, cycloalkylene or aral~yl and the main carbon .
chain can, if desired, be interrupted, for example by ., .

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oxygen, nitrogen or sulfur atoms, sulfoxide, sulfone, amine, amide, carbonyl or carboxylic ester groups. The main chain can bear as substitutents, for example, alkyl, alkoxy, aryl or aryloxy groups normally containing less than 10 carbon atoms. Especially suitable compounds of the type RlNH2 and RlR2NH are those in which R is methyl, ethyl, n- and iso- propyl, n-, iso , sec- and tert- butyl, amyl, hexyl, lauryl, cetyl, benzyl chloro-benzyl, methoxybenzyl, cyclohexyl and in the case of the secondary amines RlR2NH the R groups may be the same or any combina-tion of the aforementioned groups.
Especially suitable compounds o-f the type R'lNH2 and R'lR2NH are those in which R is a benzenoid ring which can carry substituents, for example, alkyl and alkoxy groups containing up to 10 carbon atoms and halogen atoms such as phenyl, chlorophenyl, tolyl, xylyl, naphthyl, chloronaphthyl, pyridyl, chloropyridyl and in the case of secondary amines R'lR12NH the R groups may be the same or any combination of the aforementioned groups.
Examples of particularly suitable amines fitting the general formulas RlN~2~ RlR2MH~ R lNH2~ 1 2 RlR'lNH are methylamine, dimethylamine, ethylamine,diethyl-amine, propylamine, isopropylamine, dipropylamine, diiso-propylamine, butylamine, dibutylamine, isobutylamine, di-isobutylamine, amylamine, hexylamine, oxtylamine, cetylamine, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, cyclooctylamine, benzylamine, dibenzyl-amine, p-chlorobenzylamine, aniline, p-anisidine, p-toluidine,

3,4-dichloroaniline, m-chloroaniline, diphenylamine, ~,4"-dichlorodiphenylamine, N-methylethylamine, N~methylpropyl-amine, N-methylbuty~-amine, N-methylisobutylamine, ' '. . , ~ ' ' ;' . ' .'~
~, ~ ' . ' 4ib;2 N-ethylbu-tylamine, allylamine, N-me-thylcyclohexylamine, N~methylaniline, N-ethylaniline, N-allylaniline, N-methyl-

4-chloroaniline and N-methyl-p-anisidine.
Thus, for example, using the above described amine and nitro compounds under the conditions of our invention the following ureas can be preparedo 3-(3,4-dichlorophenyl~-l,l-dimethylurea by reaction of 3,4-di-chloronitrobenzene with dimethylamine; 1,1-dimethyl-3-phenylurea by reaction of nitrobenzene with dimethylamine, 3-(p-chlorophenyl~-1, l-dimethylurea by reaction of p-chloronitrobenzene with dimethylamine; and 1,1'-(4-methyl-m-phenylene~bis~3-isopropylurea] by reaction of 2,4-dinitrotoluene with isopropylamine. O-ther combinations of amines and nitrocompounds can be used to obtain more or less readily the corresponding ureas. Such combinations are not limited -to those amines and nitrocompounds described above and are apparent to one skilled in the art.
Catalysts for use in this invention include ;~
sulfur, selenium, sulfur compounds, selenium compounds and mixtures thereof. Selenium metal has been found to be as good as most selenium compounds and is conveniently handled in the powdered form. Other suita~be selenium compounds are selenium dioxide,.selenium trioxide, mixtures ~
of these oxides, titanium diselenide, selenium dlsulfide, `
sodium selenite, zinc selenite, sodium selenide, po-tassium ~;
.: , ' seleni~de, po-tassium hydrogen selenide, hydrogen selenide, `
carbonyl selenide, barium selenide and organic selenium com-pounds. These compounds are no-t all of equivalent ac-tivi-ty.
Suitable sulfur compounds include sulfur itself, numerous inorganic sulfur compounds such as hydrogen sulfide, potassi- :
um hydrogen sulfide, potassium sulfide, sodium sulfide, ~
, '~ ' , -l,,,".. -.-.. - ., - ,...... .. .. .

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34;~2 ~ulfur dioxide, carbonyl sulfide, aluminum sul~ide, inor-ganic polysulfides such 3S ammonium polysulfide and organic sulfides and polysulfides having up to 20 carbon atoms such as diethylpolysul~ide.
The catalyst material, as indica-ted above, can be self-supported or can be deposited on an inert support or carrier for dispensing the ca-talyst to increase its effective surface. Alumina, silica, carbon, barium sulfate, calcium carbonate, organic ion exchange resins and analogous materials are useful as carriers for this purpose. ~ particular example of a supported catalyst is an ion exchange resin containing selenium as the cation and a sulfonic or carboxylic acid -function as the anionic part of the resin, such as a selenium contaiming sulfonated macroporous styrene divinylbenzene resin. Selenium or -~
s~lfur containing molecular sieves can also be employed as -~
well as complexes of selenium or s~lfur with a ligand.
Base and water is preferably added to the reacti'on unless the primary or secondary amine is used as the base.
Organic bases and metal carboxylic acid salts are effective. -Organic bases suitable -for the reaction include such amines as triethylamine, pyridine, quinoline, and n,n-dimethylaniline. Compounds normally considered as weak ~-bases, such as the metal salts of carboxylic acids, sul-fonic acids and phosphoric acid, are preferred bases.
Examples of such compounds and salts of other weak acids are lithium aceta-te, sodium acetate, potassium acetate, palladium acetate, ruthenium ace-tate, the lithium sal-t of p-toluenesulfonic acid, the li-thium salt of methyl s~
sulfonic acid, lithium acid phosphate, the lithium salt of boric acid, calcium acetate, sodium formate, lithium formate and antimony triacetate. The acid salts can be added ~,..... . .. .
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4~;2 pr~formed or can be made in the reaction mixture by adding appropriate quantities of corresponding base and acid.
There is no limit on the type of acid used or the corresponding metal oxide or hydroxide employed. Thus, aliphatic, cycloaliphatic and aromatic acids, such as propionic, octanoic, cyclohexane carboxylic/ benzoic, oxalic, malonic and the like can be employed. However, oxides or hydroxides of transition metal compounds tend to be more expensive than the alkali and alkaline earth metal hydroxides.
In those cases where unsymmetrical ureas are prepared by reaction of a nitrocompound with an amine the amine itself is of-ten suitable as a base and no other additional basic compound need be added. Even so, there are some instances where addition of a base other than -the reacting amine can be advantageous and, in such in-` stances, any of the above-described bases are suitable for this purpose.
While the process of the invention can typically be operated effectively in the absence of a solvent, a solvent can be employed. ~ro~tic solvents such as benzene, toluene, xylene; nitrile solvents such as acetonitrile and ~;
. ~
benzonitrile; amide type solvents such as N,N-dimethyl formamide and N,N-dimethyl acetamide; aliphatic, alicyclic or aromatic sulfoxide and sulfone solvents, such as dimethyl sulfoxide; aliphatic halogenated hydrocarbons such as -~ 1,1,2-trichloro- 1,2,2-trifluoroethane; halogenated aromatic hydrocarbons such as monochlorobenzene, dichlorobenzene and trichlorobenzene; ketones; esters; and ether solvents -~
such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane and the like all can be employed as solven-ts. The ether .

1 1 - ' compounds, for example can be aliphatic, aromatic or heterocyclic, and they can also be either mono or poly-ethers, or combinations o-E these compounds.
~lso suitable are the organic amines such as pyridine, triethylamine and the reactant primary and secon-dary amines used when unsymmetrical ureas are prepared.
Combinations of tertiary amines can be used as can various combinations ~f tertiary amines with primary or secondary reactant amines.
The invention is carried out with at least molar amounts of reac-tants, e., nitrocompound, amine and carbon monoxide.
Preferably, however, a molar ~xcess of the amine compound or the nitrocompound or both are present but, generally, in the case of preparing the unsymmetrical ureas, a molar excess of the amine is us~d.
' The mole ratio of the nitrocompound to the ;
catalyst can vary over a wide range, i.e from 5:1 to s 2000:1; however, a somewhat more preferred range of moles of nitrocompound to the catalys-t is 5:1 to 1000:1. It will be understood that with reference to the moles of catalyst it is meant the element selenium or sulfur and not the moles of the form in which the catalyst is charged.
Similarly, with respect to the amount of base employed the mole ratio (based on equivalent nitrogroups) can vary from 50^1 to 1.10 of the nitrocompound to the base. When the desired products are unsymmetrical 1,3-ureas which require the reaction of an amine with a nitrocompound in many cases the reacting amine can also serve as the base. When this is the case the mole ratio of nitrocompound to base may be well outside the limits ..
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described above without any detrimental effect on the reaction.
When symmetrical 1,3- ureas are the desired product by reaction of the nitrocompound, the presence of water can ~e advantageous. Thus, the mole ratio of wa-ter to catalyst, i.e. S or Se, can range from as little as about 0.5:1 to as much as 1000:1 or more. Su~h water can be added separately or produced "in situ", for example, when a base such as potassium hydroxide and an acid such as acetic acid are employed in equivalent molar amounts to give the weakly basic compound potassium acetate and water in equi-molar amounts.
The order of mixing the reactants is not critical and can be varied within the limitations of the equipment - employed. A simple procedure is to charge the ni-trogenous j compound (or compounds~, catalyst, base and/or water into the reaction vessel, introduce the proper amount of carbon monoxide and then heat -the mixture to obtain the desired reaction. ~ suitable pressure vessel, such as an auto- -clave, which is preferably provided with heating means ;
and agitation means, such as a stirrer or an-~external rocking mechanism, is employed for the reaction.
Generally, the amount o-f carbon monoxide in the free space of the reactor is sufficient to maintain the desired pressure as well as to provide a reactant for the process. ~s the reaction progresses additional carbon monoxide can be fed to the reac-tor either intermittently or continuously. ~lthough grea-ter and lesser amounts of carbon monoxide can be employed if desired, generally the total amount of carbon monoxide added during the reaction is between about 3 and about 50 moles and preferably .,~,.. .. . ... . .. .. . . ..

.. ;.. .. : . . ... , : . . . . . ... . .

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between about 8 and abou-t 15 moles of carbon monoxide per non-cyclic group in which the nitrogen atom of the nitrogenous organic compound is directly attached to a - single carbon a-tom and is also at-tached by a double bond to an o~ygen or another nitrogen atom. The highest carbon monoxide requirements are generally utilized in a process in which carbon monoxide is added continuously, but suitable recycle of carbon monoxide containing gas streams gr~atly reduces the overall consumption of carbon monoxide.
The reaction temperature is generally maintained in the range of about 50C. to about 250C. and preferably within the range of from about 100 -to about 200C. These temperatures ranges permit a cOnVeniRnt rate of reaction to be achieved while avoiding undesirable side reactions.
It will be understood, however, -that any elevated -tempera- -tures below that at which the starting materials or the products decompose can be used. The reaction is carried out, as indicated above, at superatmospheric pressures which is normally between abuut 10 and 200 atmospheres, although higher or lower reaetion pressures can be employed if other reaction conditions are suitably adjusted. Preferably, however, only moderate carbon monox- -ide pressures in the range of about 10 to about 100 atmosph-eres are employed and the reaction is conveniently run at a temperature of below about 200C. within this pres-sure range.
While the reaction o-f the present invention is normally carried out batchwise, if desired, the reaction can be carried out semi-continuously or even continuously~
Ion exchange type catalysts, for example, are particularly suited for continuous reactions. The reaction time is ' ; '. , . ., ' ' '~ '' ' ; - ' ' . ~ ' ~' . , . ' ' ' ~4Z~t;;2 dependent upon the nature of the reactants, temperature, pressure and the type of catalyst employed, as well as the -type of equipment which is used. Nor~nally -the reaction time is less than 180 minutes and generally the effective ness of the catalysts of this invention permits the reac-tion to be completed wi-thin a time period between about ten minutes and about 120 minutes.
. .
~fter the reaction has been comple-ted, the temperature of the reaction mixture can be dropped to ambient te~perature and the pressure vessel vented. The reaction product is then treated by conventional procedures, including filtration, distillation, or o-ther suitable separation techniques, to effect separation of urea from ~-unreacted starting material, solvent, by-product, catalyst, ~` etc.
The invention is further illustrated by, but not ; limited to, the following examples.
The reactions set forth in these examples were all run in 316 Stainless Steel shaking autoclaves. It ~ ~
will be understood, however, that less expensive forms of -stainless steel can be used and that if desired equivalent reaGtion vessels, such as glasslined vessels, can be employed.
Conversions and yields reported in the examples were de~ermined by gas chromatographic analysis and by isola-tion of the product. The ureas were purified by recrystalliza-tion and the infrared spectra and meltinq points obtained.

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EXAMPL E
; Ten milliliters of nitrobenzene, 100 milliliters of tetrahydrofuran and two milliliters of water were charged into a 300 milliliter~;xocking autoclave along with 1.0 grams of selenium metal (gxey powder~ and 1.0 grams of sodium acetate. The autoclave was flushed with nitrogen and carbon monoxide and finally pressured to 800 psig with carbon monoxide. ~fter heating to 150C. for one hour the autoclave was cooled, vented and -the contents analyzed.
~ 66.3 per cent conversion of nitrobenzene resulted with a 33.8 per cent yield of purified carbanalide.
EXAMPLE II
Example I was repeated at 180C. using 0.5 grams water. ~ 48.9 per cent conversion resulted with a 57.7%
yield of pure carbanalide.
EXAMPLE III
The autoclave was charged with 13.7 grams of 4-nitrotoluene, 100 milliliters of tetrahydrofuran, 1.0 grams of sodium acetate, 1.0 gram of selenium metal and -~
0.5 milliliters of water. After flushing with nitrogen and carbon monoxide it was pressured to 800 psig with carbon monoxide and heated to 180C. for one hour. After cooling and venting analysis indicated a 61.0 per cent con-version and a yield of pure 1,3-d~-p-tolylurea of 45.9 per cent.
EXAMPLE IV
Similarly, 15.3 grams of 4-nitroanisole was reacted along with 100 milliliters of tetrahydrofuran, 1.0 gram selenium metal, 1.0 gram sodium acetate and 0.5 milliliters of H20 at an initial carbon monoxide pressure of 800 psig. ~fter one hour at 180C. a 68 per cent -.: . - .. .. : . ............ ; :.: . ~. .
:-:~., . ~ . ::, , . : : :
.. : :'' : - ;:, .

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conversion was obtained giving a 44.1 per cent yield of pure 1,3-bis (4-methox~phenyl) urea.
The follo~ing examp:les demonstrate the use o~
this invention to prepare unsymmetrical ureas by reaction of a ni~ro compound with an amine.
EXAMPLE V
Ten milliliters of nitrobenzene, 100 milliliters of tetrahydrofuran, 1.0 gram potassium acetate, 1.0 gram selenium metal and 9.0 grams of dimethylamine are charged to the autoclave. The au-toclave is flushed and pressured ;
to 800 psig with carbon monoxide and heated to 180C. for one hour. ~ter reaction 1,1-dimethyl-3-phenylurea is ~
obtained. ~ ; -EX~VPLE VI
Ten milliliters of nitrobenzene, 100 milliliters of tetrahydrofuran, 1.0 gram potassium acetate, 1.0 gram ;~
selenium and 21.4 grams of p-toluidine are charged to the autoclave which is then flushed and pressured to 800 psig -;
with carbon monoxide. The temperature is raised to 180C ;
for one hou~ glving 1-p-tolyl-3-phenylure~ as product.

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Claims (13)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for the production of ureas which comprises contacting at an elevated temperature and pressure in a basic solution a nitrogenous organic compound selected from the group consisting of organic nitro, nitroso, azo and azoxy compounds containing up to 24 carbon atoms, with carbon monoxide and a compound selected from the group consisting of water and a primary or secondary amine containing 1 to 20 carbon atoms, in the present of an active amount of a catalyst selected from the group consisting of selenium, sulfur, compounds containing selenium and inorganic or organic sulphides and mixtures thereof.

2. The method as claimed in Claim 1 wherein said nitro compound is a nitro aromatic compound.

3. The method as claimed in Claim 2 wherein said nitro aromatic compound is nitrobenzene.

4. The method as claimed in Claim 2 wherein said nitro aromatic compound is nitrotoluene.

5. The method as claimed in Claim 2 wherein said nitro aromatic compound is 4-nitroanisole.

6. The method as claimed in Claim 1 wherein said nitro compound is a tertiary nitroaliphatic compound.

7. The method as claimed in Claim 1 wherein said nitrogenous organic compound is reacted with carbon monoxide and water.

8. The method as claimed in Claim 7 wherein said catalyst is selenium.

9. The method as claimed in Claim 7 wherein said catalyst is sulfur.

10. The method as claimed in Claim 1 wherein said nitrogenous organic compound is reacted with carbon monoxide and a primary or secondary amine containing 1 to 20 carbon atoms.

11. The method as claimed in Claim 10 wherein said secondary amine is dimethylamine.

12. The method as claimed in Claim 10 wherein said primary amine is p-toluidine.

13. The method as claimed in Claim 1 wherein said temperature is in the range of from 50°C. to 250°C and said pressure is in the range of from 10 atmospheres to 200 atmospheres.