Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
  • C07C273/18—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas
  • C07C273/1809—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas with formation of the N-C(O)-N moiety
  • C07C273/1836—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas with formation of the N-C(O)-N moiety from derivatives of carbamic acid
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C269/00—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C269/00—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
  • C07C269/04—Preparation of derivatives of carbamic acid, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups from amines with formation of carbamate groups

Definitions

• This invention relates to a process for the carbonylation of a nitrogen-containing organic compound by reacting said compound with carbon monoxide in the presence of a rhodium or ruthenium catalyst.
• a f ew ref erence s have taught the addi ti on of a primary amino compound (and/or related compounds, such as urea, biurets, and allophanates) to further improve the rate and selectivity of reactions catalyzed by a platinum group metal compound in combination w ith a redox-active - metal halide-cocatalyst.
• a primary amino compound and/or related compounds, such as urea, biurets, and allophanates
• Patent 4 , 178 ,455 discloses that, in a process for converting nitroaromatic to urethane catalyzed by a platinum, palladium, rhodium, or ruthenium compound and a Lew is-acid promoter, the rate and selectivity are improved by adding to the reaction, an organic primary am ino compound, a urea compound, a biuret compound, an allophanate compound, or a mixture thereof.
• the preferred Lew is acid promoters are redox-active metal salts, especially iron chlorides. This patent illustrates (by example) only palladium catalysts with iron chloride promoters.
• pyridine in large molar excess is utilized to suppress corrosion in a process utilizing a catalyst system comprising (1) palladium, ruthenium, rhodium or compounds thereof, and (2) a Lewis Acid, e.g. ferric chloride.
• a catalyst system comprising (1) palladium, ruthenium, rhodium or compounds thereof, and (2) a Lewis Acid, e.g. ferric chloride.
• a Lewis Acid e.g. ferric chloride
• U.S. Patents 4,219,661; 4,262,130; and 4,339,592 teach palladium catalysts with iron oxide and iron chloride co-catalysts in which addition of tertiary amines is one embodiment.
• Patent 4,297,501 discloses a process in which mixtures of a primary amine and a nitroaromatic are carbonylated to urethane with a Group VIII noble metal compound and an oxychloride compound capable of undergoing redox reactions.
• the nitroaromatic corresponds to the primary amine, and the patent teaches the following reaction stoichiometr :
• U.S. 4,304,922 similarly discloses a process in which mixtures of N,N'-diaryl urea and nitroaromatic are carbonylated to urethane with the same catalyst/co- catalyst systems of U.S. 4,297,501. Illustrated by examples are PdCl 2 , RhCl 3 , IrCl 3 , PtCl 4 and RUCI3 as Group VIII noble metal compounds. Iron oxychloride and several other redox active metal oxides and chlorides are illustrated as co-catalysts. In examples in which redox active metal oxides are used, anilinium hydrochloride is also added to provide active anionic chloride. In the preferred embodiment of this patent, the N,N*-diaryl urea and nitroaromatic have the same aryl groups, and the patent teaches that the following reaction stoichiometry is obtained:
• Patent 4,304,922 illustrates that when RhCl ⁇ is used as catalyst in combination with iron oxychloride as co-catalyst, nitrobenzene and N,N'- diphenylurea (1:2 molar ratio) are both consumed (100% and 99% conversion, respectively) to give urethane product 99% selectivity based on nitrobenzene plus N,N'-diphenylurea).
• Japan Kokai 55-7227 discloses a process in which molecular hydrogen is notice added, to a process for carbonylating nitroaromatic, in the presence of a palladium catalyst, to increase the reaction rate.
• the description of the invention specifies a palladium catalyst, accompanied by promoters such as tertiary amines, iron and vanadium compounds, and chlorine ions. All illustrated examples use a supported palladium- selenium on carbon catalyst promoted with pyridine and either FeCl or VOCI3 (these are redox-active metal chlorides).
• the patent teaches that the addition of hydrogen causes hydrogenation of a fraction of the nitroaromatic to generate the corresponding primary arylamine in situ..
• 3,338,956 discloses a metal carbonyl catalyst of Group VIA, VIIA, or VIIIA for this reaction.
• U.S. Patent 3 ,993,685 teaches the addition of tertiary amines, especially pyridine, to platinum group metal catalysts to obtain improved activity in the absence of redox-active metal co-catalysts.
• Rhodium chloride and hydridocarbonyl tris (triphenyl-phosphine) rhodium in combination with pyridine are exemplified.
• the result obtained by adding a primary amine to a rhodium or ruthenium catalyst system essentially free from redox-active metal components is substantially different from the result obtained when a primary amine is added to either Group VIII metal catalysts (including ruthenium, rhodium and palladium) in the presence of redox active metal co-catalysts or certain palladium catalysts in the absence of redox active metal co-catalysts.
• Group VIII metal catalysts including ruthenium, rhodium and palladium
• the present invention provides a process for converting a nitrogen-containing organic compound, selected from the group consisting of nitro, nitroso, azo, and azoxy compounds, into a carbamic acid derivative by reacting said nitrogen-containing organic compound with carbon monoxide wherein the improvement comprises the steps of:
• step (b) contacting the solution of step (a) with carbon monoxide, in the presence of a catalyst essentially free of redox active metal halide components and comprising rhodium or ruthenium at conditions sufficient to convert said nitrogen- containing organic compound into said carbamic acid derivative.
• Said carbamic acid derivative may be a urethane or a urea (depending on whether a hydroxyl containing organic compound is included in the solution of step (a).) If the solution of step (a) includes only the nitrogen-containing compound and the primary amine —and any inert solvent— the carbamic acid derivative will be a urea, which may be separated and alcoholyzed to the urethane in a separate step.
• the present invention provides a process for preparing a urethane by reacting a nitrogen-containing organic compound, selected from the group consisting of nitro, nitroso, azo and azoxy compounds, with carbon monoxide and a hydroxyl-containing organic compound, the improvement which comprises the steps of:
• step (d) recovering a primary amine, in an amount equal or greater than the primary amine in the primary amine-containing solution of step (a).
• the primary amine recovered is equal to or greater than the primary amine initially provided in the reactant solution.
• the primary amine can be constantly recycled and no further addition of primary amine, urea, hydrogen, etc. is needed to maintain the desired rate and selectivities.
• the primary amine (illustrated by anil ine) is an intermediate in the f ormation of urethane from the nitrogen-containing organic compound, but is not in net produced or consumed by the desired net reaction. It has been found that the primary amine is not in net consumed and the desired reaction stoichiometry is obtained even when primary amine is initially added to the reaction. It has been further found that the rate of conversion of nitrogen-containing organic compound to urethane and the selectivity of the reaction are increased when the initial amount of primary amine added to the reaction is increased. The initial amount of primary amine and its favorable effects on the rate and selectivity of the reaction persist for the conversion of an indefinite amount of nitrogen-containing organic compound to urethane.
• the primary amine can be provided directly or by the in situ alcoholysis of a urea, biuret, or allophanate compound.
• Urea is alcoholyzed to form amine and urethane: RNHCONHR + R*OH— ⁇ RNH 2 + RNHC0 2 R'
• Biurets and allophanates similarly provide primary amine by alcoholysis under the reaction conditions.
• a fraction of the nitrogen-containing compound e.g. nitrobenzene
• the primary amine aniline
• the primary amine may also be provided in situ by the addition of water, in which case a fraction of the nitrogen- containing compound is reduced to primary amine by hydrogen equivalents obtained from shifting water and carbon monoxide to carbon dioxide.
• the carbonyl compounds which result from dehydrogenation of alcohol react with the primary amine to form undesired condensation products and water. Additional nitrogen-containing compound may then be reduced to the primary amine by hydrogen equivalents derived from water by the shift reaction.
• the selectivity of urethane production is increased by increasing the amine-to-alcohol ratio.
• the amine-to- alcohol ratio is increased by increasing the amine concentration and/or by decreasing the alcohol concentration.
• the primary amine may become the maj or reaction solution component and act as solvent.
• the alcohol concentration may be independently decreased by using an inert solvent in pl ace of excess al cohol in the initial reaction solution.
• N, N'-disubstituted urea is present in the reaction mixture during the reaction.
• nitrobenzene is reacted with alcohol, anil ine, or many inert solvents as solvent
• the N, N'- diphenyl-urea appears as a solid in samples of the reaction mixture which are cool ed.
• the sol id has been f iltered from the solution components of such samples (including the soluble catalyst) , and characteriz ed as N, N' -diphenyl urea.
• the amount of urea present during the reaction depends on the amine-to-al cohol ratio ini tially present. The higher the ratio, the higher the amount of urea present. When enough alcohol is provided, however, little or no urea persists to the end of the reaction. At the end of the reaction it is substantially reacted w ith alcohol to make urethane according to equation (4) . Some or pe rhaps all of the urethane appear s to be f orme d v ia oxidative cabonylation to am ine to urea, followed by urea al coholysis :
• urea wherein no primary amine, urea, biuret or allophanate is present
• a fraction of the nitrogen-containing organic compound e.g. nitrobenzene
• the nitrogen-containing organic compound e.g. nitrobenzene
• the molar ratio of hydrogen to the nitrogen-containing organic compound is less than 1, the remainder of the nitrogen- containing organic compound is converted to urea by the desired reaction stoichiometry.
• an improved yield of urea is obtained when from 50 to about 60 percent of the nitrogen-containing organic compound is converted to primary amine, by hydrogenation, with the maximum being obtained at 50 percent conversion.
• the amine concentration decreases during the reaction, and the observed rate of nitrogen-containing organic compound conversion corespondingly decreases during the reaction.
• the molar ratio of nitrogen-containing organic compound to the primary amine is greater than 1, not all of the nitrogen- containing compound will be converted to urea. Thus, in the absence of alcohol, there will be unreacted nitrogen- containing organic compound left when all of the primary amine is consumed into urea. If the amine is used in large excess to the nitro compound (as solvent, for example) however, the fractional changes in amine concentration and rate of urea production are small or insignificant.
• the overall selectivity of urethane synthesis can be increased by separating the urea synthesis and urea alcoholysis into two process steps, so that the selectivity reducing reactions of the alcohol in the catalytic carbonylation step are avoided.
• the nitrogen-containing organic compound usef ul in the process of this invention will contain at least one non-cyclic group in which a nitrogen atom is directly attached to a singl e ca rbon atom and through a doubl e bond to oxygen or another nitrogen atom.
• the nitrogen- containing organic compound is selected f rom the group consisting of nitro, nitroso, azo and azoxy compounds.
• Suitable nitrogen-containing organic compounds for use in the process of this invention are compounds represented by the general formulae:
• R and R are radicals independently selected from the group consisting of C to C 2Q hydrocarbyl radicals and substituted derivatives thereof, x is an integer of from 1 to 2 , y is an integer of f rom 1 to 3 , and z is an intege r of from 0 to 1.
• the substituted hydrocarbyl radical may include hetero atoms selected f rom the group consisting of halogen, oxygen, sulfur, nitrogen and phosphorus atoms.
• the nitrogen-containing compounds represented by formula I include nitro compounds (wherein x is 2) and nitroso compounds (wherein x is 1) .
• Suitable nitro compounds are mononitro compounds such as nitrobenzene, alkyl and alkoxy nitrobenzenes wherein the alkyl group contains up to 10 carbon atoms, aryl and aryloxy nitrobenzenes, wherein the aryl group is phenyl, toyl, naphthyl, xylyl, chlorophenyl, chloronitrobenzenes, a inonitrobenzenes, carboalkoxy amino nitrobenzenes wherein the alkoxy group has up to 10 carbon atoms, aryl and aryloxy dinitrobenzenes, trinitro compounds such as trinitrobenzene, alkyl and alkoxytrinitrobenzenes, aryl and aryloxytrinitrobenzenes, the substituents being any of those al ready mentioned and chlorotrinitrobenz ene
• Substituted or unsubstituted al iphatic nitro compounds such as nitromethane, nitrobutane, 2 ,2 '-dimethyl nitrobutane, nitrocyclopentane, 3-methylnitrobutane, nitrooctadecane, 3-nitropropene-l , phenyl nitromethane, p-bromophenyl nitromethane, p-methoxy phenyl nitromethane,dinitroethane, dinitrohexane, dinitrocycl ohexane, di- (nitrocycl ohexyl) -methane are also suitable.
• the above nitro compounds may include more than one of the above substituents (in addition to the nitro group (s ) such as in nitroaminoal kylbenz enes, , nitroalkyl carboal koxy amino benzenes, etc.
• Suitable nitroso compounds are the aromatic nitroso compounds such as nitrosobenzene, nitrosotoluene, dinitrosobenzene, dinitrosotol uene and the aliphatic nitroso compounds such as nitrosobutane, nitrosocyclohexane and dinitrosomethylcyclohexane.
• the nitrogen-containing compounds represented by Formula II include both azo compounds (wherein z is 0) and azoxy compounds (wherein z is 1).
• Suitable compounds represented by Formula II include azobenzene, nitroazobenzne, chloroazobenzene, alkyl or aryl substituted azobenzene, azoxybenzene, nitroazoxybenzene, chloroazoxybenzene, etc.
• the primary amine compound utilized in this invention may be selected from the group consisting of compounds represented by the general formula:
• Examples of such primary amines include methylamine, ethylamine, butylamine, hexylamine, ethylenediamine, propylenediamine, butylenediamine, cyclohexylamine, cyclohexyldiamine, aniline, p-toluidine, o-m-and p-diaminobenzenes, amino- .
• methylcarbanilic acid esters especially the 5-amino-2 methyl-, 2-amino-5-methyl-, and 3-amino-2-methyl carboalkoxyaminobenzenes, wherein said alkoxy group has up to 10 cabon atoms, o-, m- and p-nitroanilines, nitroaminotoluenes, especially those designated above, o- and p-phenylenedi amine, benzylamine, o-amino-p-xylene, 1- aminophthaline, 2,4-and 2,6-diaminotoluenes, 4,4'- diaminodibenzyl, bis (4-aminophenyl) thioether, bis (4- aminophenyl) sulfone,, 2,4,6-triaminotoluene, o-, m-and p- chloroanilines, p-bromoaniline, l-fluoro-2,4- diaminobenzene
• those which can be derived from the starting nitro compound are preferred.
• nitrobenzene is used as the starting aromatic nitro compound
• anil ine is preferred.
• 2-amino-4-nitrotoluene, 4-amino-2- nitrotoluene, and 2,4-diaminotoluene are pref erably used when the starting aromatic nitro compound is 2 ,4- dinitrotoluene
• 2-amino-6-nitrotoluene, and 2,6- diaminotol uene are pref erably used when the starting aromatic nitro compound is 2 ,6-dinitrotoluene.
• the primary amine compound can be provided by the in- situ decomposition of the corresponding urea or biuret as represented by compounds having the general formulae :
• R j is as def ined above.
• R ⁇ may represent different radicals in the same compound. That is non-symmetrical ureas and biurets, e . g.
• no particul ar l imitation is placed on the amount of primary amine used.
• it i s pref erably used i n an amount equal to f rom 0.1 to 100 m ol es per gm-atom of ni trogen in the nitrogen-containing organic compound.
• Suitable solvents include, for example, aromatic solvents such as benzene, toluene, xylene, etc.; nitriles such as acetonitrile, benzonitrile, etc.; sulfones such as sulfolane, etc.; halogenated aliphatic hydrocabons such as l,l,2-trichloro-l,,2,2,- trifluoroethane, etc.; halogenated aromatic hydrocarbons such as monochlorobenzene, dichlorobenzene, trichlorobenzene, etc.; ketones; esters; and other solvents such as tetrahydrof uran, 1,4-dioxane, 1,2- dimethoxyethane, etc.
• aromatic solvents such as benzene, toluene, xylene, etc.
• nitriles such as acetonitrile, benzonitrile, etc.
• sulfones
• hydroxy-containing organic compounds for use in the process of this invention include compounds represented by the general formula
• Hydroxy compounds suitable for use in the process of the present invention may be, for example, mono- or polyhydric alcohols containing primary, secondary or tertiary hydroxyl groups as well as mono- and polyhydric phenols. Mixtures of these hydroxy compounds may also be * used.
• the alcohols may be aliphatic or aromatic and may bear other substituents in addition to hydroxyl groups but the substituents should (except as hereinafter described) preferably be non-reactive to carbon monoxide under the reaction conditions.
• phenol and monohydric alcohols such as methyl, ethyl, n- and sec-propyl, n-, iso, sec-and tert butyl, amyl, hexyl, lauryl, cetyl, benzyl, chlorobenzyl and methoxy benzyl • alcohols as well as diols such as ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol, triols such as glycerol, trimethylol propane, hexanetriol, tetrols such as pentaerythritol and the ethers of such polyols providing that at least one hydroxyl group remains unetherif ied.
• diols such as ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol
• triols such as glycerol, trimethylol propane, hexanetriol
• tetrols such as pentaerythr
• the etherifying group in such ether alcohols normally contains up to 10 carbon atoms and is pref erably an al kyl, cycloalkyl or aralkyl group which may be substituted w ith, for example, a halogen or an alkyl group.
• the most pref erred hydroxy 1-containing organic compound f or use in the proce ss of thi s i nvention is methyl alcohol or a simil ar lower alkanol , e.g. a C j to C5 alcohol .
• the process of this invention includes the use of any mixture of nitro compounds, nitroso compounds, azo or azoxy compounds w ith any mixture of hydroxy compounds and al so the use of compounds containing both functions, i.e. hydroxynitro compounds, hydroxy nitroso compounds, hydroxyazo and hydroxyazoxy compounds such as 2- hydroxynitroe thane, 2-hydroxynitrosoethane, nitrophenol s, ni tronaphthols, nitrosophenols, nitrosonaphthols, hydr oxyaz Tavernznes and hydr oxyazoxybenz enes. Mixtures of these nitrogen-containing compounds may also be used.
• the catalyst util iz ed in the process of this invention may be selected f rom the group consisting of ⁇ rhodium or ruthenium salts, e.g. the hal ides, nitrate, sulfate, a cetate, f ormate, carbonate, etc. and rhodium or ruthenium compl exes (especially rhodium or ruthenium carbonyl complexes) including ligands capable of coordinating w ith the rhodium or ruthenium atom.
• the complex may include one or more rhodium or ruthenium atoms and suitabl e l igands may include carbon-carbon unsaturated groups as in ethylene, isobutylene, cyclohexene, norbornadiene, cyclooctatetraene.
• Other suitabl e l igands include acetylacetonate (acac), hydrogen atoms, carbon monoxide, nitric oxide, alkyl-radicals, alkyl or aryl nitriles or isonitriles, nitrogen-containing heterocyclic compounds such as pyridine, piperidine, and organo phosphines, arsines or stilbines.
• a rhodium or ruthenium catalyst for use in the present process further comprises a polyamino ligand having at least two tertiary amino groups capable of coordinating with rhodium.
• a polyamino ligand having at least two tertiary amino groups capable of coordinating with rhodium.
• such polyamino ligand may be selected from the group of compounds represented by the general formula:
• ligands according to the general formula are 1,2-bis (diethylamino)ethane 1,2- bis(dimethylamino)propane, 1,2-bis (dimethylamino)ethane, 1,2-bis (di-t-butylamino)ethane, 1,2- bis (diphenylamino)ethane, 1,2-bis (diphenylamino)propane, 1,2-bis (diphenyla ino)butane, 2,2'-bipyridine, 2,2'- biquinoline, bispyridylglyoxal, and 1,10-phenanthroline and derivatives thereof. Preference is given to the use of 2,2'-bipyridine and 1,10-phenanthroline.
• the catalyst utilized in the process of this invention may comprise a bis-phosphino rhodium or ruthenium compound.
• the bis-phosphino rhodium or ruthenium compound may also include the above anions, i.e. sulfate, acetate, trifluoroacetate, formate, carbonate, etc. and/or other ligands, discussed above, cpable of coordinating with the rhodium or ruthenium atom.
• the bis-phosphino rhodium or ruthenium compound may include more than one rhodium or ruthenium atom.
• the bis-phosphino ligand of the rhodium or ruthenium catalyst may be represented by the general formula:
• R 3 R 4
• R 7 P-R 9 -P (R 7 ) (Rg)
• R 3 R 4
• R7 and Rg are as defined above and Rg is a divalent radical providing sufficient spacing to enable both phosphorus atoms to coordinate with a rhodium or ruthenium atom.
• Rg may be a hydrocarbyl having from 1 to 10 atoms or a substituted derivative thereof including one or more heteroatoms selected from the group connsisting of halogen, oxygen, sulfur, nitrogen, and phosphorus atom.
• Rg comprises from 2 to 6 carbon atoms.
• suitable bis phosphine ligands include bis (l,2-diphenylphosphino)benzene, bis(l,2- di phenyl hosphino) -ethane, bis (3,3- diphenylphosphino)propane, etc.
• the rhodium or the ruthenium catalyst is preferably utilized as a homogeneous. catalyst and therefore one criteria for the selection of the rhodium or ruthenium compound is its solubility under the condi tions of reaction in the mixture of the nitrogen-containing organic compound and the primary amino compound (and, if desired, the hydroxy 1-containing organic compound) .
• the rhodium or ruthenium compound is al so selected with a view toward the catalytic activity of the compound. Mixtures of rhodium and ruthenium compounds may be used.
• the rhodium or ruthenium compound comprising a polyamino ligand or a bi s-phosphino ligand may be preformed or f ormed in s itu in the reaction solution by separately dissolving a rhodium or a ruthenium compound and the respective l igand. Since the catalyst is util iz ed in very l ow concentration, it is preferred that the compound is preformed to ensure that such l igand w ill be coordinated with the rhodium or ruthenium during the reaction.
• the rhodium or ruthenium catalyst may be used in mixture with co-catalysts or pr omoters so long as the co- catalyst, unl ike the redox-active metal hal ide co- catalysts of the prior art, does not change the reactivi ty of the catalyst system to consume added amines.
• Mono- ter tiary amines are one class of suitable pr omoters f or the rhodium catalysts of this invention.
• Sui tabl e *mono- ter tiary amines are those described in U. S. 3 ,993 ,685 herein incorporated by reference.
• the catalyst is free of halide to avoid corrosion problems.
• d i n amounts equal to at l ea st 1 mol e pe r g - atom of nitrogen in the nitrogen-containing compound.
• the amount of the rhodium or ruthenium compound used as the catalyst may vary widely according to the type thereof and other reaction conditions. However, on a weight basis, the amount of catalyst is generally in the range of from 1 X 10 " ⁇ to 1 part, and preferably from 1 X 10 ⁇ 4 to 5 X 10 "" ⁇ parts, per gram-atom of nitrogen in the starting nitrogen-containing organic compound when expressed in terms of its metallic component.
• the reaction temperature is generally held in the range of 80° to 230° C, and preferably in the range of from 100° to 200° C.
• the reaction pressure is generally in the range of from 10 to 1,000 kg/cm 2 G, and preferably from 30 to 500 kg/cm 2 G.
• the reaction time depends on the nature and amount of the nitrogen-containing organic compound used, the reaction temperature, the reaction pressure, the type and amount of catalyst used, the type of reactor employed, and the like, but is generally in the range of from 5 minutes to 6 hours.
• the reaction mixture is cooled and the gas is discharged from the reactor. Then, the reaction mixture is subjected to any conventional procedure including filtration, distillation, or other suitable separation steps, whereby the resulting urethane or urea is separated from any unreacted materials, any by-products, the solvent, the catalyst, and the like.
• the urethanes and the ureas prepared by the process of the invention have wide applications in the manufacture of agricultural chemicals, isocyanates, and polyurethanes.
• the invention is more fully illustrated by the following examples. However, they are not to be construed to limit the scope of the invention.
• reaction was conducted in batch mode in a 300 ml stainless steel autoclave reactor equipped with a stirring mechanism which provides constant dispersion of the gas through the liquid solution. Heating of the reaction is provided by a jacket-type furnace controlled by a proportioning controller.
• the autoclave is equipped with a high pressure sampling system for removal of small samples of the reaction solution during the reaction in order to monitor the reaction progress. Reaction solutions were prepared and maintained under anaerobic conditions. Reaction samples were analyzed by gas chromatography.
• Example 2 The procedure was the same as for Example 1 except that 9.32g (0.100 mole) aniline was initially provided to the reaction. The volume of methanol ws reduced so that the total solution volume was again 75 ml. Complete conversion of nitrobenzene occurred over 3.5 hours at 160°C and yielded 0.088 mole methyl N-phenylcarbamate (88% selectivity based on nitrobenzene) and 0.112 mole aniline (12% selectivity to additional aniline based on nitrobenzene ) .
• the amine concentration and amine-to-alcohol ratio may be further increased by replacing more alcohol in the initial solution w ith amine.
• Amine may become the maj or reaction solution component and thus act as solvent for the reaction.
• the a ine-to-alcohol ratio may also be increased by simply replacing some of the excess alcohol with an inert solvent.
• Example 2 The procedure was the same as Example 1 except only 6.40g (0.200 mole) methanol was initially provided to the reaction solution. Toluene was added as an inert solvent to again give a total solution volume of 75 ml. Complete conversion of nitrobenzene occurred in 8.5 hours at 160°C yielding 0.095 mole methyl N-phenyl carbamate (95% selectivity based in nitrobenzene) and 0.054 mole aniline (4% selectivity to additional aniline based on nitrobenzene) .
• Example 1 wherein the ratio of methanol to nitrobenzene was 15:1, the selectivity was 76%, while in this Example, wherein the ratio of methanol to nitrobenzene was 2:1, the selectivity was increased to 95%.
• a ratio of methanol (or other hydroxy-containing organic compound) to nitrobenzene (or other nitrogen-containing organic compound) of less than 15:1, more preferably a ratio of from 1:1 to 5:1, most preferably a ratio of from 1:1 to 3:1, e.g. about 2:1.
• Example 4 The procedure was the same as for Example 3 except that no methanol is provided to the reaction. Additional tol uene solvent was added to again give 75 ml total reaction solution. Af ter 10 hour s at 160°C, 0.048 mole nitrobenzene and 0.008 mole aniline remained (52% and 42% conversion, respectively) . The mixture contained copious amounts of a white organic colid. After cooling, the sol id w as f iltered and characterized (IR, NMR) as predominantly N, N'-diphenyl urea. The spectra and the excess consumption of nitrobenzene over anil ine indicate that N, N , ,N"-triphenylbiuret was al so present.
• Example 4 During the course of the urea synthesis of Example 4, the observed rates of nitrobenzene and aniline conversion decreased as the anil ine was consumed. However, the anil ine-dependent rate of nitrobenzene conversion to urea in this experiment was approximately equal to the anil ine- dependent rates of nitrobenzene conver sion to urethane in the expe r iment s of Exampl es 1 and 4. Thi s show s th at ur ea synthesis is kinetically competent to account f or all of urethane synthesis in the presence of alcohol.
• Example 2 The procedure was the same as for Example 1 except that 0.23g (1.40 millimole) tetraethylammoniumchloride was also provided to the reaction. Complete conversion of nitrobenzene occurred over 6.0 hours at 160°C and yielded 0.077 mole methyl N-phenylcarbamate (77% selectivity based on nitrobenzene) and 0.071 mole aniline (21% selectivity to additional anil ine based on nitrobenzene ) .
• Example 6 The procedure was the same as for Example 6 except that no aniline was initially provided to the reaction. Commplete nitrobenzene conversion required 15 hours at 160°C. Selectivities based on nitrobenzene were 60% to methyl N-phenylcarbamate and 34% to aniline.
• Example 6 shows that the rate and selectivity of the reaction are improved by initially providing primary amine to the reaction, when the reaction also includes chloride ion.
• Example 6 also shows that the amine is not, in net, consumed when the reaction contains chloride ion.
• the amine is consumed in the presence of redox-active metal chloride co- catalysts, it is the additional presence of the redox- active metal which causes the amine consumption.
• Example 7 The procedure was the same as for Example 7 except that no aniline was initially provided to the reaction. Additional toluene solvent was added to again give a total initial solution volume of 75 ml. After 1.5 hours at 160°C under carbon monoxide, 0.023 mole nitrobenzene remained and no products were observed by the gas chromatographic analytical system. The mixture was cooled, methanol was added, and the gas was changed to nitrogen as in Example 7. After 1.0 hours at 160°C under nitrogen, the solution contained 0.013 mole nitrobenzene, 0.003 mole anil ine, 0.001 mole N-methylene anil ine, 0.004 mole N-methyl aniline, and less than 0.001 mole methyl N- phenyl carbamate.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Priority Applications (4)

Applications Claiming Priority (10)

Publications (1)

Family

ID=27505505

Family Applications (1)

Country Status (9)

Cited By (2)

Citations (4)

• 1986
  • 1986-02-25 BR BR8605693A patent/BR8605693A/pt unknown
  • 1986-02-25 EP EP19860901706 patent/EP0215848A4/en not_active Withdrawn
  • 1986-02-25 WO PCT/US1986/000415 patent/WO1986005179A1/en not_active Application Discontinuation
  • 1986-02-25 AU AU55403/86A patent/AU586591B2/en not_active Ceased
  • 1986-02-27 KR KR1019860001367A patent/KR940003065B1/ko active IP Right Grant
  • 1986-03-03 CA CA000503125A patent/CA1276166C/en not_active Expired - Lifetime
  • 1986-10-24 DK DK511286A patent/DK511286D0/da not_active Application Discontinuation
  • 1986-11-03 NO NO86864387A patent/NO166711C/no unknown
  • 1986-11-04 FI FI864485A patent/FI864485A/fi not_active IP Right Cessation

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events