CA1150292A - Preparation of aromatic urethanes - Google Patents
Preparation of aromatic urethanesInfo
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- CA1150292A CA1150292A CA000346047A CA346047A CA1150292A CA 1150292 A CA1150292 A CA 1150292A CA 000346047 A CA000346047 A CA 000346047A CA 346047 A CA346047 A CA 346047A CA 1150292 A CA1150292 A CA 1150292A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
- C07C271/06—Esters of carbamic acids
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Abstract
ABSTRACT OF THE DISCLOSURE:
Aromatic urethanes are prepared by reacting aromatic amines with hydroxy compounds, carbon monoxide and oxygen or nitro compounds at elevated temperatures and superatmospheric pressure, using special selenium or sulfur catalysts. The aromatic urethanes obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents, drugs and polyurethanes.
Aromatic urethanes are prepared by reacting aromatic amines with hydroxy compounds, carbon monoxide and oxygen or nitro compounds at elevated temperatures and superatmospheric pressure, using special selenium or sulfur catalysts. The aromatic urethanes obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents, drugs and polyurethanes.
Description
29~
- 1 - O.Z. 0050/033719 Preparation of aromatic urethanes The present invention relates to a novel process for the preparation of aromatic urethanes by reacting aromatic amines with hydroxy compounds, carbon monoxide and oxygen or nitro compounds at elevated temperatures and superatmospheric pressure, using special noble metal catalysts or selenium or sulfur catalysts.
m e conventional methods of industrial preparation of urethanes are the reaction of hydroxy compounds with isocyanates (Houben-Weyl, Methoden der Organischen Chemie, Volume 8, pages 141 - 142) or of chlorocarbonic acid esters with amines (Houben-Weyl, Methoden der Organischen Chemie, Volume 8, page 138), both the iso-cyanates and the chlorocarbonic acid esters generally being obtained by phosgenation, of the corresponding amines and alcohols respectively. The use of phosgene, which is highly toxic, necessitates expensive measures to protect the environment.
Chem. Letters, (1972), 373 - 374, discloses the reaction of aniline with equimolar amounts of selenium and with ten-fold molar amounts of triethylamine and - methanol, whilst passing carbon monoxide into the mixture, to give the triethylamine salt of N-phenylselenocarbamic acid, which is then converted in a second stage, whilst passing oxygen into the mixture, to methyl N-phenyl-carbamate. The yield of 30 per cent, and the unecono-mical procedure of having to use a large excess of tri- -ethylamine, are disadvantages of the process; furthermore, ~l~V29;~
hydrogen selenide is formed in stoichiometric amounts during the reaction, and this requires special safety measures in carrying out the reaction.
J. Org. Chem., 28 (1963), 585 - 586 discloses, as the outcome of investigations concerning the optimum conditions of preparation, that a yield of 2~.3 per cent of methyl N-phenylcarbamate is obtained by employing a molar ratio of aniline to sulfur, instead of selenium, of from 1 : 1.05 to 1 : 1.5, a molar ratio of aniline to added triethylamine of from 1 : 0.1 to 1 : 0.5, and an excess of methanol. The article points out expressly that these constitute the optimum conditions and that the method, which is unsatisfactory in respect of yield, simplicity and economy, is incapable of giving a better yield; furthermore, a stoichiometric amount of hydrogen sulfide is formed, and this also demands substantial safety measures.
It has now been found that aromatic urethanes may be obtained in an advantageous manner by catalytic reaction of an aromatic amine with a hydroxy compound, carbon monoxide and an oxidizing agent if the reaction is carried out with oxygen or a nitro compound as the oxidizing agent, in the presence of a catalytic amount of a selenium-containing and/or sulfur-containing catalyst, together with an additional basic com-pound as an auxiliary catalyst, at not less than 100C and under a pressure of not less than 50 bar.
Where aniline and methanol are used, with oxygen or nitrobenzene as the oxidizing agent, the reaction may be represented by the following equations:
a) 2 ~ NH2+2C0~2CH30H+02 __~ 2 ~ NHC02CH3 + 2H20 b) 2 ~ NH2+3co+3cH3oH + ~ N02 > 3 ~ NHC02CH3 +
Compared to the conventional processes, the process according to the invention gives aromatic urethanes in better yield, higher space-time yield and greater purity. These advantageous results are surprising in view of the prior art.
Furthermore, the reaction according to the invention, employing nitro compounds as oxidizing agents, was unexpected because it is known that organic nitro compounds react with amines and carbon monoxide in the presence of tertiary amines as aux-iliary bases, of palladium compounds as catalysts and of xylene as a solvent, at elevated temperatures under superatmos-3~5~3Z92 _ 4 _ o.Z. 0050/033719pheric pressure, to give good yields of urea compounds (J. Org. Chem, 40 (1975), 2,819 - 2,822).
The amine and the hydroxy compound can be reacted with one another in stoichiometric amounts or using an excess of either relati~e to the other; ad~antageously, however, from 1 to 100, especially from 5 to 50, equi-valents of hydroxy compound are used per amino group in the amine. Preferred urethanes are monourethanes and diurethanes, and compounds of the formula . ~ H I, Rl-a- -N-C-O-R2 . _ O _ n lo preferred amines are monoamines and diamines and com-pounds of the formula R1-a ~.~H2] II, and preferred hydroxy compounds are those of the ~ormula R2-OH III;
in these formulae, Rl is a monova1ent or-divalent aro-matic radical, preferably phenyl which is unsubstituted or is substituted by one or more, especially 1, 2 or 3, alkyl groups, alkoxy groups of 1 to 4 carbon atoms, bromine atoms, fluorine atoms and/or chlorine atoms, or is phenylene, diphenylmethane, diphenylene-methane, naphthyl or naphthylene, R2 is an aliphatic, araliphatic, cycloalîphatic or aromatic radical, preferably alkyl of .. . , _ .
~15~329Z
- 5 - o.z. 0050/033719 1 to 18, especially of 1 to 7, carbon atoms, cycloalkyl o~ 5 to 8 carbon atoms, aralkyl or alkylaryl of 7 to 12 carbon atoms, or phenyl, n is 1 and a is a single bond or n is 2 and a is 2 single bonds. The above radicals may additionally be substituted by groups and/or atoms which are inert under the reaction conditions, for exam-ple alkyl or alkoxy, each of 1 to 4 carbon atoms.
Examples of suitable starting materials II are:
aniline; a- and ~-naphthylamine; anilines substituted in the o-position, m-position or p-position by chlorine, bromine, methyl, ethyl, propyl, isopropyl, butyl, sec.-butyl, tert.-butyl, isobutyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert.-butoxy or sec.-butoxy, and correspondingly substituted a- and ~-naphthyl-amines; anilines carrying two identical or different substituents from those enumerated above, in the 2,3-,
- 1 - O.Z. 0050/033719 Preparation of aromatic urethanes The present invention relates to a novel process for the preparation of aromatic urethanes by reacting aromatic amines with hydroxy compounds, carbon monoxide and oxygen or nitro compounds at elevated temperatures and superatmospheric pressure, using special noble metal catalysts or selenium or sulfur catalysts.
m e conventional methods of industrial preparation of urethanes are the reaction of hydroxy compounds with isocyanates (Houben-Weyl, Methoden der Organischen Chemie, Volume 8, pages 141 - 142) or of chlorocarbonic acid esters with amines (Houben-Weyl, Methoden der Organischen Chemie, Volume 8, page 138), both the iso-cyanates and the chlorocarbonic acid esters generally being obtained by phosgenation, of the corresponding amines and alcohols respectively. The use of phosgene, which is highly toxic, necessitates expensive measures to protect the environment.
Chem. Letters, (1972), 373 - 374, discloses the reaction of aniline with equimolar amounts of selenium and with ten-fold molar amounts of triethylamine and - methanol, whilst passing carbon monoxide into the mixture, to give the triethylamine salt of N-phenylselenocarbamic acid, which is then converted in a second stage, whilst passing oxygen into the mixture, to methyl N-phenyl-carbamate. The yield of 30 per cent, and the unecono-mical procedure of having to use a large excess of tri- -ethylamine, are disadvantages of the process; furthermore, ~l~V29;~
hydrogen selenide is formed in stoichiometric amounts during the reaction, and this requires special safety measures in carrying out the reaction.
J. Org. Chem., 28 (1963), 585 - 586 discloses, as the outcome of investigations concerning the optimum conditions of preparation, that a yield of 2~.3 per cent of methyl N-phenylcarbamate is obtained by employing a molar ratio of aniline to sulfur, instead of selenium, of from 1 : 1.05 to 1 : 1.5, a molar ratio of aniline to added triethylamine of from 1 : 0.1 to 1 : 0.5, and an excess of methanol. The article points out expressly that these constitute the optimum conditions and that the method, which is unsatisfactory in respect of yield, simplicity and economy, is incapable of giving a better yield; furthermore, a stoichiometric amount of hydrogen sulfide is formed, and this also demands substantial safety measures.
It has now been found that aromatic urethanes may be obtained in an advantageous manner by catalytic reaction of an aromatic amine with a hydroxy compound, carbon monoxide and an oxidizing agent if the reaction is carried out with oxygen or a nitro compound as the oxidizing agent, in the presence of a catalytic amount of a selenium-containing and/or sulfur-containing catalyst, together with an additional basic com-pound as an auxiliary catalyst, at not less than 100C and under a pressure of not less than 50 bar.
Where aniline and methanol are used, with oxygen or nitrobenzene as the oxidizing agent, the reaction may be represented by the following equations:
a) 2 ~ NH2+2C0~2CH30H+02 __~ 2 ~ NHC02CH3 + 2H20 b) 2 ~ NH2+3co+3cH3oH + ~ N02 > 3 ~ NHC02CH3 +
Compared to the conventional processes, the process according to the invention gives aromatic urethanes in better yield, higher space-time yield and greater purity. These advantageous results are surprising in view of the prior art.
Furthermore, the reaction according to the invention, employing nitro compounds as oxidizing agents, was unexpected because it is known that organic nitro compounds react with amines and carbon monoxide in the presence of tertiary amines as aux-iliary bases, of palladium compounds as catalysts and of xylene as a solvent, at elevated temperatures under superatmos-3~5~3Z92 _ 4 _ o.Z. 0050/033719pheric pressure, to give good yields of urea compounds (J. Org. Chem, 40 (1975), 2,819 - 2,822).
The amine and the hydroxy compound can be reacted with one another in stoichiometric amounts or using an excess of either relati~e to the other; ad~antageously, however, from 1 to 100, especially from 5 to 50, equi-valents of hydroxy compound are used per amino group in the amine. Preferred urethanes are monourethanes and diurethanes, and compounds of the formula . ~ H I, Rl-a- -N-C-O-R2 . _ O _ n lo preferred amines are monoamines and diamines and com-pounds of the formula R1-a ~.~H2] II, and preferred hydroxy compounds are those of the ~ormula R2-OH III;
in these formulae, Rl is a monova1ent or-divalent aro-matic radical, preferably phenyl which is unsubstituted or is substituted by one or more, especially 1, 2 or 3, alkyl groups, alkoxy groups of 1 to 4 carbon atoms, bromine atoms, fluorine atoms and/or chlorine atoms, or is phenylene, diphenylmethane, diphenylene-methane, naphthyl or naphthylene, R2 is an aliphatic, araliphatic, cycloalîphatic or aromatic radical, preferably alkyl of .. . , _ .
~15~329Z
- 5 - o.z. 0050/033719 1 to 18, especially of 1 to 7, carbon atoms, cycloalkyl o~ 5 to 8 carbon atoms, aralkyl or alkylaryl of 7 to 12 carbon atoms, or phenyl, n is 1 and a is a single bond or n is 2 and a is 2 single bonds. The above radicals may additionally be substituted by groups and/or atoms which are inert under the reaction conditions, for exam-ple alkyl or alkoxy, each of 1 to 4 carbon atoms.
Examples of suitable starting materials II are:
aniline; a- and ~-naphthylamine; anilines substituted in the o-position, m-position or p-position by chlorine, bromine, methyl, ethyl, propyl, isopropyl, butyl, sec.-butyl, tert.-butyl, isobutyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert.-butoxy or sec.-butoxy, and correspondingly substituted a- and ~-naphthyl-amines; anilines carrying two identical or different substituents from those enumerated above, in the 2,3-,
2,4-, 2,5-, 2,6-, 3,4- or 3,5-position, and correspondingly substituted - and ~-naphthylamines; o-, m- and p-amino-diphenylmethane, corresponding diaminodiphenylmethanes and monoaminodiphenylmethanes and diamino-diphenylmethanes monosubstituted or disubstitutedby the above substituents; anilines monosubstituted by an additional amino group, or disubstituted by an amino group and another of the-substituents enumerated above, in the positions enumerated above, and correspondingly substituted a- and ~-naphthylamines. Advantageous starting materials are m- and p-diaminobenzene, o-, m-and p-aminotoluene, 2,4- and 2,6-diaminotoluene, o-, m-and p-chloroaniline, 2,4-, 3,4- and 3,5-dichloroaniline, . . , ~
- 6 - O.Z. 0050/033719 o- and p-anisidine, 1,5-diaminonaphthalene and all the substituted and unsubstituted diaminodiphenylmethanes referred to above; aniline, 2,4- and 2,6-diaminotoluene,
- 6 - O.Z. 0050/033719 o- and p-anisidine, 1,5-diaminonaphthalene and all the substituted and unsubstituted diaminodiphenylmethanes referred to above; aniline, 2,4- and 2,6-diaminotoluene,
3,5-dichloroaniline, 4,4'- and 2,4'-diaminodiphenyl-methane and 1,5-diaminonaphthalene are particularly pre-ferred.
Examples of suitable starting materials III are the following alcohols: methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, he~yl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, cetyl alcohol, margaric (heptadecyl) alcohol, stearyl alcohol, 2-ethylhexanol, methylpentanol; isobutyl alcohol, sec.-butyl alcohol, tert.-butyl alcohol~ isoamyl alcohol, isohexyl alcohol, isoheptyl alcohol, isooctyl alcohol, isononyl alcohol, isodecyl alcohol, isoundecyl alcohol, isododecyl alcohol, isotridecyl alcohol, isotetradecyl alcohol, isopentadecyl alcohol, isohexadecyl alcohol, isoheptadecyl alcohol and isooctadecyl alcohol; ethylene glycol monoethers and propylene glycol monoethers obtained by reacting the above fatty alcohols of 10 to 20 carbon atoms with 2, 3, 4 or 5 moles of ethylene oxide or propylene oxide per mole of alcohol, and corresponding glycol monoethers of the above fatty alcohols obtained by simultaneous reaction with ethylene oxide and propylene oxide in the above molar ratios; methyl-ethylene glycol, ethyl-ethylene glycol, n-propyl-ethylene glycol, iso-propyl-ethylene glycol, n-butyl-ethylene glycol, ;29Z
- 7 - o.z. 0050tO337l9 isobutyl-ethylene glycol, sec.-butyl-ethylene glycol, tert.-butyl-ethylene glycol, methyl-1,2-propylene glycol, ethyl-1,2-propylene glycol, cyclohexanol, benzyl alcohol, cyclopentanol, cycloheptanol, phenylethyl alcohol, phenyl-propanol, phenol, cyclooctanol, 2-methylphenol, 3-methyl-phenol, 4-methylphenol, 2-methoxyphenol, 3-methoxyphenol,
Examples of suitable starting materials III are the following alcohols: methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, he~yl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, cetyl alcohol, margaric (heptadecyl) alcohol, stearyl alcohol, 2-ethylhexanol, methylpentanol; isobutyl alcohol, sec.-butyl alcohol, tert.-butyl alcohol~ isoamyl alcohol, isohexyl alcohol, isoheptyl alcohol, isooctyl alcohol, isononyl alcohol, isodecyl alcohol, isoundecyl alcohol, isododecyl alcohol, isotridecyl alcohol, isotetradecyl alcohol, isopentadecyl alcohol, isohexadecyl alcohol, isoheptadecyl alcohol and isooctadecyl alcohol; ethylene glycol monoethers and propylene glycol monoethers obtained by reacting the above fatty alcohols of 10 to 20 carbon atoms with 2, 3, 4 or 5 moles of ethylene oxide or propylene oxide per mole of alcohol, and corresponding glycol monoethers of the above fatty alcohols obtained by simultaneous reaction with ethylene oxide and propylene oxide in the above molar ratios; methyl-ethylene glycol, ethyl-ethylene glycol, n-propyl-ethylene glycol, iso-propyl-ethylene glycol, n-butyl-ethylene glycol, ;29Z
- 7 - o.z. 0050tO337l9 isobutyl-ethylene glycol, sec.-butyl-ethylene glycol, tert.-butyl-ethylene glycol, methyl-1,2-propylene glycol, ethyl-1,2-propylene glycol, cyclohexanol, benzyl alcohol, cyclopentanol, cycloheptanol, phenylethyl alcohol, phenyl-propanol, phenol, cyclooctanol, 2-methylphenol, 3-methyl-phenol, 4-methylphenol, 2-methoxyphenol, 3-methoxyphenol,
4-methoxyphenol, 2,3-dimethylphenol, 3,4-dimethylphenol, 2,6-dimethylphenol, 3,5-dimethylphenol, 2,3-dimethoxy-phenol, 3,4-dimethoxyphenol and 3,5-dîmethoxyphenol.
The reaction is in general carried out at from 100 to 220C, preferably from 130 to 210C, especially from 140 to 200C, under a pressure of from 50 to 1,000 bar, preferably from 100 to 600 bar, batchwise or con-tinuously. The requisite pressure is advantageously obtained by means of the gases used, advantageously carbon monoxide and/or air or oxygen, and the autogenous pressure of the reaction mixture at the chosen temperature.
m e reaction can be carried out in the absence of a sol-vent or in the presence of a solvent which is inert under the reaction conditions. Advantageously, a reactant, for example the hydroxy compound, is used as the solvent.
Examples of other solvents which may be used are aromatic hydrocarbons~ eg. toluene, o-, m- and p-xylene and mesity-lene, and aromatic halohydrocarbons, especially chloro-hydrocarbons, eg. chloronaphthalene, dichloronaphthalene, chlorobenzene, fluorobenzene, o-, p- and m-dichlorobenzene, o-, m- and p-chlorotoluene and 1,2,4-trichlorobenzene.
Toluene, xylenes and mixtures of these are preferred.
The amount of solvent used is advantageously from 100 ~5VZ9~
to 10,000 per cent by weight, preferably from 200 to 1,000 per cent by weight, based on starting material II.
The carbon monoxide is employed in the stoichio-metric amount or in excess, advantageously in an amount of from 10 to 50, especially from 15 to 30, moles per amino group in the starting material II.
- ~L150292 In the process according to the invention it is possible to use, as first alternative, selenium-containing catalysts, especially selenium in.the form of the element or of selenium compounds. Examples of the latter are metal selenides, SeOC12 and TiSe2; the use of Se, SeS2 and COSe is preferred. The selenium-containing catalysts are used in catalytic amounts, advantageously of from 0.1 to 10, espe-clally from 0.5 to 5, per cent by weight of selenium (regard-l~ess of the actual constitution or composition of the selenium-containing catalyst), based on starting material II.
. _ ., ~ . .. . .
11~2~2 In the process according to the invention it is also possible to use, as second alternative, sulfur-containing catalysts, as a rule sulfur in the form of the element or of compounds of divalent sulfur. Examples of suitable catalysts are ammonium, sodium and potassium sulfides and polysulfides;
elementary sulfur, H2S, COS, Na2Sx and K2Sx ( x 2 6) are preferred. The sulfur-containing catalysts are as a rule employed in catalytic amounts, advantageously of from 0.5 to 20, especially from 3 to 10, per cent by weight of sulfur (regardless of the actual constitution or composition of the catalyst), based on starting material II.
Both in alternative 1) and in alternative 2), an additional basic compound is employed as an auxiliary catalyst.
The process according to the invention is as a rule carried out with a catalytic amount, advantageously of from 1 to 20, preferably from 5 to 15, per cent by weight of the basic com-pound, based on starting material II. Preferred basic com-pounds are alkaline earth metal salts and alkali metal salts, in particular salts of phosphoric acid and or alkanecarboxylic acids, and tertiary amines, as well as mixtures of these.
Specific examples of suitable basic compounds are potassium phosphate, sodium phosphate, lithium phosphate, calcium phos-phate, zinc acetate, sodium formate, sodium acetate, sodium propionate, sodium butyrate, sodium isobutyrate, potassium formate, potassium acetate, potassium propionate, potassium butyrate, 3Z9~
- ll - O.Z. 0050/033719 potassium isobutyrate, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, tri-isobutylamine, tri-sec.-butylamine, tri-tert.-butylamine, tribenzylamine, tricyclohexylamine, triamylamine, tri-hexylamine, N,N-dimethylaniline, N,N-diethylaniline, N,N-dipropylaniline, N,N-dimethyltoluidine, N,N-diethyl-toluidine, ~,N-dipropyltoluidine, N,N-dimethyl-p-amino-pyridine, N9N-diethyl-p-aminopyridine, N,N-dipropyl-p-aminopyridine, N-methylpiperidine, N-ethylpiperidine, lo N-methylpyrrolidine, N-ethylpyrrolidine, N-methylimidazole, pyridine, isoquinoline, quinoline, ~-picoline, ~-picoline, r-picoline, 2,6-lutidine and 2,4-lutidine; especially preferred compounds are triethyiamine, dimethylethylamine, methyldiisopropylamine, pyridine, p-dimethylaminopyridine, 1,4-diazabicyclo-G2,2,2]-octane, diazabicycloundecene, diazabicyclononene, lithium acetate, sodium acetate and potassium acetate.
me oxidizing agents are advantageously employed in a ratio of from 0.3 to l, preferably from 0.4 to 0.6, mole of nitro compound per amino group in the starting material II or, in the case of oxygen - advantageously in the form of air - as the oxidizing agent, in a ratio of from 0.1 to 5, preferably from 0.25 to 2, especially from 0.5 to l.5, mole of oxygen per amino group in the starting material II. Where organic nitro com~ounds are used as oxidizing agents, an advantageous embodiment is to use the nitro compounds corresponding to the amines II emp-loyed, if only to avoid the formation of by-products.
In this way, part or all of the o~idizing agent may be lZ92 - 12 - O.Z. 0050/033719 reduced to the aromatic amine and then undergo reaction, as starting material II, in accordance wlth the invention.
Hence, suitable nitro compounds are all compounds which correspond to the above amines with one or more or all of the amino groups replaced'by nitro groups. Prefer-red nitro compounds are nitrobenzene, Z,4!_ and 4,4'-di-nitrodiphe~ylmethane, 1,3-dinitrobenzene, 2,4-dinitro-toluene, 2,6-dinitrotoluene, o-nitrotoluene, p-nitro-toluene, 3-nitro-1,2-dimethylbenzene, 4-nitro-1,2-dimethyl-lo benzene, 2-nitro-1,3-dimethylbenzene, 4-nitro-1,3-dimethyl-benzene, 5-nitro-1,3-dimethylbenzene, 1,5-dinitronaphtha-lene, o-, m- and p-nitroaniline and p-chloronitrobenzene;
amongst these, nitrobenzene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, 3,5-dichloronitrobenzene and p-nitrotoluene are especially preferred.
The reaction may be carried out as follows: a mixture of starting materialsII and III, carbon monoxide, oxidizing agent and catalyst with or without auxiliary catalyst and/or solvent, is kept at the reaction temperature and reaction pressure for from l to 3.5 hours.
The end product I is isolated from the reaction mixture in a conventional manner, as a rule by filtration and fractional distillation or crystallization.
The aromatic urethanes obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents, drugs and polyurethanes. Regarding their use, reference may be made to the prior art publications cited and to Ullmanns Encyklopadie der technischen Chemie, Volume 5, pages 73 . ~
~,' . .
3Z~ ' to 76. The urethanes may be converted to corresponding isocyanates by elimination of alcohols or to corresponding ureas by reaction with amines (see also German Laid-Open Application DOS 2,635,490 and U.S. Patent 3,919,278).
In the Examples which follow, parts are by weight and bear the same relation to parts by volume as that of the kilogram to the liter.
9.3 parts of aniline, 83.7 parts of ethanol, 0.093 part of selenium and 0.5 part of 1,4-diazabicyclo-~2,2,2~-octane are introduced into an autoclave. The autoclave is sealed and charged with 200 bar of carbon monoxide and 50 bar of air. The mixture is then heated for 2 hours at from 100C
to 150C, whilst stirring, after which the autoclave is cooled and emptied. After removing the catalyst, 11.6 parts (74~ of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compourid being determined by gas chromatography.
The conversion, based on starting material II, is 95 per cent.
EXA~lPLE 2 Using a method similar to Example 1, 9.3 parts of aniline, 83.7 parts of ethanol, 0.1 part of sulfur and 0.5 part of 1,4-diazabicyclo-~2,2,2~-octane are mixed and kept for 2.5 hours at 190C under a pressure of 200 bar of carbon monoxide and 50 bar of air. 4.6 parts (71.5% of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compound being determined by gas chromatography. The conver-sion, based on starting material II, is 39 per centO
EXAMPL~ 3 Using a method similar to Example 1, 9.3 parts of aniline, 100 parts of ethanol, 0.06 part of selenium and 0.6 part of 1,4-diazabicyclo-~2,2,2~-octane are mixed. Instead of introducing air, 6.2 parts of nitrobenzene are added, and the ~1543Z92 mixture is reacted at 150C for 2 hours under a carbon mon-oxide pressure of 500 bar. 2.3 parts (84.5% of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compound being determined by gas chromatography. The conver-sion, based on starting material II, is 11 per cent. 24 per cent of the nitrobenzene have reacted.
Using a method similar to Example 3, 4 parts of 2,4-diaminotoluene, 100 parts of ethanol, 0.15 part of selenium, 0.3 part of 1,4-diazabicyclo-[2,2,2]-octane and 3 parts of 2,4-dinitrotoluene are kept for 2 hours at 80C undex a carbon monoxide pressure of 300 bar. Air to a pressure of 50 bar is then additionally forced in. The mixture is heated for 3 hours at 190C. 3.7 parts (29.9~ of theory) of toluylene 2,4-diethylurethane, melting point 109C, and 5.6 parts of a mixture of toluylene 2-amino-4-ethylurethane and toluylene 4-amino-2-ethylurethane are obtained. The total selectivity, based on urethanes, is 87 per cent. The conver-sion, based on starting material II, is 96 per cent. The dinitrotoluene has reacted completely.
Using a method similar to Example 3, 9.3 parts of aniline, 100 parts of ethanol, 0.3 part of selenium, 0.6 part of 1,4-diazabicyclo-C2,2,2]-octane and 6.8 parts of p-nitro-toluene are heated for 2 hours at from 100C to 150C under a carbon monoxide pressure of 500 bar. 7.1 parts (71.7% of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compound being determined by gas chromatography.
The conversion, based on starting material II, is 60 per cent.
Using a method similar to Example 1, 9.9 parts of 4,~'-diamino-diphenylmethane, 100 parts of methanol, 1 part of ~15~Z9;~
selenium and 2 parts of 1,4-diazabicyclo-~2,2,2~-octane are introduced into an autoclave. The latter is sealed and charged with 200 bar of carbon monoxide and 50 bar of air.
The mixture is then heated for 3 hours at from 100C to 180C
whilst stirring, and the autoclav~ is cooled and emptied.
After separating off the catalyst, 9.5 parts (69.3~ of theory) of 4,4'-bis-(carbomethoxyamino)-diphenylmethane, melting point 189C, and 3,3 parts of 4-amino-4'-carbomethoxyaminodiphenyl-methane are obtained; the total selectivity in respec-t of urethanes is 98 per cent. The conversion, based on starting material II, is 87 per cent.
.
~r ~
i ~ 15 ~
The reaction is in general carried out at from 100 to 220C, preferably from 130 to 210C, especially from 140 to 200C, under a pressure of from 50 to 1,000 bar, preferably from 100 to 600 bar, batchwise or con-tinuously. The requisite pressure is advantageously obtained by means of the gases used, advantageously carbon monoxide and/or air or oxygen, and the autogenous pressure of the reaction mixture at the chosen temperature.
m e reaction can be carried out in the absence of a sol-vent or in the presence of a solvent which is inert under the reaction conditions. Advantageously, a reactant, for example the hydroxy compound, is used as the solvent.
Examples of other solvents which may be used are aromatic hydrocarbons~ eg. toluene, o-, m- and p-xylene and mesity-lene, and aromatic halohydrocarbons, especially chloro-hydrocarbons, eg. chloronaphthalene, dichloronaphthalene, chlorobenzene, fluorobenzene, o-, p- and m-dichlorobenzene, o-, m- and p-chlorotoluene and 1,2,4-trichlorobenzene.
Toluene, xylenes and mixtures of these are preferred.
The amount of solvent used is advantageously from 100 ~5VZ9~
to 10,000 per cent by weight, preferably from 200 to 1,000 per cent by weight, based on starting material II.
The carbon monoxide is employed in the stoichio-metric amount or in excess, advantageously in an amount of from 10 to 50, especially from 15 to 30, moles per amino group in the starting material II.
- ~L150292 In the process according to the invention it is possible to use, as first alternative, selenium-containing catalysts, especially selenium in.the form of the element or of selenium compounds. Examples of the latter are metal selenides, SeOC12 and TiSe2; the use of Se, SeS2 and COSe is preferred. The selenium-containing catalysts are used in catalytic amounts, advantageously of from 0.1 to 10, espe-clally from 0.5 to 5, per cent by weight of selenium (regard-l~ess of the actual constitution or composition of the selenium-containing catalyst), based on starting material II.
. _ ., ~ . .. . .
11~2~2 In the process according to the invention it is also possible to use, as second alternative, sulfur-containing catalysts, as a rule sulfur in the form of the element or of compounds of divalent sulfur. Examples of suitable catalysts are ammonium, sodium and potassium sulfides and polysulfides;
elementary sulfur, H2S, COS, Na2Sx and K2Sx ( x 2 6) are preferred. The sulfur-containing catalysts are as a rule employed in catalytic amounts, advantageously of from 0.5 to 20, especially from 3 to 10, per cent by weight of sulfur (regardless of the actual constitution or composition of the catalyst), based on starting material II.
Both in alternative 1) and in alternative 2), an additional basic compound is employed as an auxiliary catalyst.
The process according to the invention is as a rule carried out with a catalytic amount, advantageously of from 1 to 20, preferably from 5 to 15, per cent by weight of the basic com-pound, based on starting material II. Preferred basic com-pounds are alkaline earth metal salts and alkali metal salts, in particular salts of phosphoric acid and or alkanecarboxylic acids, and tertiary amines, as well as mixtures of these.
Specific examples of suitable basic compounds are potassium phosphate, sodium phosphate, lithium phosphate, calcium phos-phate, zinc acetate, sodium formate, sodium acetate, sodium propionate, sodium butyrate, sodium isobutyrate, potassium formate, potassium acetate, potassium propionate, potassium butyrate, 3Z9~
- ll - O.Z. 0050/033719 potassium isobutyrate, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, tri-isobutylamine, tri-sec.-butylamine, tri-tert.-butylamine, tribenzylamine, tricyclohexylamine, triamylamine, tri-hexylamine, N,N-dimethylaniline, N,N-diethylaniline, N,N-dipropylaniline, N,N-dimethyltoluidine, N,N-diethyl-toluidine, ~,N-dipropyltoluidine, N,N-dimethyl-p-amino-pyridine, N9N-diethyl-p-aminopyridine, N,N-dipropyl-p-aminopyridine, N-methylpiperidine, N-ethylpiperidine, lo N-methylpyrrolidine, N-ethylpyrrolidine, N-methylimidazole, pyridine, isoquinoline, quinoline, ~-picoline, ~-picoline, r-picoline, 2,6-lutidine and 2,4-lutidine; especially preferred compounds are triethyiamine, dimethylethylamine, methyldiisopropylamine, pyridine, p-dimethylaminopyridine, 1,4-diazabicyclo-G2,2,2]-octane, diazabicycloundecene, diazabicyclononene, lithium acetate, sodium acetate and potassium acetate.
me oxidizing agents are advantageously employed in a ratio of from 0.3 to l, preferably from 0.4 to 0.6, mole of nitro compound per amino group in the starting material II or, in the case of oxygen - advantageously in the form of air - as the oxidizing agent, in a ratio of from 0.1 to 5, preferably from 0.25 to 2, especially from 0.5 to l.5, mole of oxygen per amino group in the starting material II. Where organic nitro com~ounds are used as oxidizing agents, an advantageous embodiment is to use the nitro compounds corresponding to the amines II emp-loyed, if only to avoid the formation of by-products.
In this way, part or all of the o~idizing agent may be lZ92 - 12 - O.Z. 0050/033719 reduced to the aromatic amine and then undergo reaction, as starting material II, in accordance wlth the invention.
Hence, suitable nitro compounds are all compounds which correspond to the above amines with one or more or all of the amino groups replaced'by nitro groups. Prefer-red nitro compounds are nitrobenzene, Z,4!_ and 4,4'-di-nitrodiphe~ylmethane, 1,3-dinitrobenzene, 2,4-dinitro-toluene, 2,6-dinitrotoluene, o-nitrotoluene, p-nitro-toluene, 3-nitro-1,2-dimethylbenzene, 4-nitro-1,2-dimethyl-lo benzene, 2-nitro-1,3-dimethylbenzene, 4-nitro-1,3-dimethyl-benzene, 5-nitro-1,3-dimethylbenzene, 1,5-dinitronaphtha-lene, o-, m- and p-nitroaniline and p-chloronitrobenzene;
amongst these, nitrobenzene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, 3,5-dichloronitrobenzene and p-nitrotoluene are especially preferred.
The reaction may be carried out as follows: a mixture of starting materialsII and III, carbon monoxide, oxidizing agent and catalyst with or without auxiliary catalyst and/or solvent, is kept at the reaction temperature and reaction pressure for from l to 3.5 hours.
The end product I is isolated from the reaction mixture in a conventional manner, as a rule by filtration and fractional distillation or crystallization.
The aromatic urethanes obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents, drugs and polyurethanes. Regarding their use, reference may be made to the prior art publications cited and to Ullmanns Encyklopadie der technischen Chemie, Volume 5, pages 73 . ~
~,' . .
3Z~ ' to 76. The urethanes may be converted to corresponding isocyanates by elimination of alcohols or to corresponding ureas by reaction with amines (see also German Laid-Open Application DOS 2,635,490 and U.S. Patent 3,919,278).
In the Examples which follow, parts are by weight and bear the same relation to parts by volume as that of the kilogram to the liter.
9.3 parts of aniline, 83.7 parts of ethanol, 0.093 part of selenium and 0.5 part of 1,4-diazabicyclo-~2,2,2~-octane are introduced into an autoclave. The autoclave is sealed and charged with 200 bar of carbon monoxide and 50 bar of air. The mixture is then heated for 2 hours at from 100C
to 150C, whilst stirring, after which the autoclave is cooled and emptied. After removing the catalyst, 11.6 parts (74~ of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compourid being determined by gas chromatography.
The conversion, based on starting material II, is 95 per cent.
EXA~lPLE 2 Using a method similar to Example 1, 9.3 parts of aniline, 83.7 parts of ethanol, 0.1 part of sulfur and 0.5 part of 1,4-diazabicyclo-~2,2,2~-octane are mixed and kept for 2.5 hours at 190C under a pressure of 200 bar of carbon monoxide and 50 bar of air. 4.6 parts (71.5% of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compound being determined by gas chromatography. The conver-sion, based on starting material II, is 39 per centO
EXAMPL~ 3 Using a method similar to Example 1, 9.3 parts of aniline, 100 parts of ethanol, 0.06 part of selenium and 0.6 part of 1,4-diazabicyclo-~2,2,2~-octane are mixed. Instead of introducing air, 6.2 parts of nitrobenzene are added, and the ~1543Z92 mixture is reacted at 150C for 2 hours under a carbon mon-oxide pressure of 500 bar. 2.3 parts (84.5% of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compound being determined by gas chromatography. The conver-sion, based on starting material II, is 11 per cent. 24 per cent of the nitrobenzene have reacted.
Using a method similar to Example 3, 4 parts of 2,4-diaminotoluene, 100 parts of ethanol, 0.15 part of selenium, 0.3 part of 1,4-diazabicyclo-[2,2,2]-octane and 3 parts of 2,4-dinitrotoluene are kept for 2 hours at 80C undex a carbon monoxide pressure of 300 bar. Air to a pressure of 50 bar is then additionally forced in. The mixture is heated for 3 hours at 190C. 3.7 parts (29.9~ of theory) of toluylene 2,4-diethylurethane, melting point 109C, and 5.6 parts of a mixture of toluylene 2-amino-4-ethylurethane and toluylene 4-amino-2-ethylurethane are obtained. The total selectivity, based on urethanes, is 87 per cent. The conver-sion, based on starting material II, is 96 per cent. The dinitrotoluene has reacted completely.
Using a method similar to Example 3, 9.3 parts of aniline, 100 parts of ethanol, 0.3 part of selenium, 0.6 part of 1,4-diazabicyclo-C2,2,2]-octane and 6.8 parts of p-nitro-toluene are heated for 2 hours at from 100C to 150C under a carbon monoxide pressure of 500 bar. 7.1 parts (71.7% of theory) of N-phenylethylurethane, melting point 52C, are obtained, the compound being determined by gas chromatography.
The conversion, based on starting material II, is 60 per cent.
Using a method similar to Example 1, 9.9 parts of 4,~'-diamino-diphenylmethane, 100 parts of methanol, 1 part of ~15~Z9;~
selenium and 2 parts of 1,4-diazabicyclo-~2,2,2~-octane are introduced into an autoclave. The latter is sealed and charged with 200 bar of carbon monoxide and 50 bar of air.
The mixture is then heated for 3 hours at from 100C to 180C
whilst stirring, and the autoclav~ is cooled and emptied.
After separating off the catalyst, 9.5 parts (69.3~ of theory) of 4,4'-bis-(carbomethoxyamino)-diphenylmethane, melting point 189C, and 3,3 parts of 4-amino-4'-carbomethoxyaminodiphenyl-methane are obtained; the total selectivity in respec-t of urethanes is 98 per cent. The conversion, based on starting material II, is 87 per cent.
.
~r ~
i ~ 15 ~
Claims (12)
1. A process for the preparation of aromatic ure-thanes by catalytic reaction of an aromatic amine with a hydroxy compound, carbon monoxide and an oxidizing agent, wherein the reaction is carried out with oxygen or a nitro compound as the oxidizing agent, in the presence of a catalytic amount of a selenium-containing and/or sulfur-containing cata-lyst, together with an additional basic compound as an aux-iliary catalyst, at not less than 100°C and under a pressure of not less than 50 bar.
2. A process as claimed in claim 1, wherein the reaction to give a urethane of the formula I, is carried out with an amine of the formula II, and a hydroxy compound of the formula R2-OH III, where R1 is a monovalent or divalent aromatic radical, R2 is an aliphatic, araliphatic, cycloaliphatic or aromatic radical, n is 1 and a is a single bond or n is 2 and a is 2 single bonds.
3. A process as claimed in claim 1, wherein the reaction is carried out at from 100 to 220°C.
4. A process as claimed in claim 1, wherein the reaction is carried out at from 130 to 210°C.
5. A process as claimed in claim 1, wherein the reaction is carried out under a pressure of from 50 to 1,000 bar.
6. A process as claimed in claim 2, wherein the reaction is carried out in the presence of from 100 to 10,000 per cent by weight, based on starting material II, of a solvent which is inert under the reaction conditions.
7. A process as claimed in claim 2, wherein the reaction is carried out with carbon monoxide in an amount of from 10 to 50 moles per amino group of starting material II.
8. A process as claimed in claim 2, wherein the reaction is carried out with from 0.1 to 10 per cent by weight of selenium (regardless of the actual constitution or composi-tion of the selenium-containing catalyst), based on starting material II.
9. A process as claimed in claim 2, wherein the reaction is carried out with from 0.5 to 20 per cent by weight of sulfur (regardless of the actual constitution or composition of the catalyst), based on starting material II.
10. A process as claimed in claim 2, wherein the reaction is carried out with from 1 to 20 per cent by weight, based on starting material II, of a basic compound.
11. A process as claimed in claim 2, wherein the reaction is carried out with from 0.3 to 1 mole of nitro compound per amino group in the starting material II.
12. A process as claimed in claim 2, wherein the reaction is carried out with from 0.1 to 5 moles of oxygen per amino group in the starting material II.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19792910132 DE2910132A1 (en) | 1979-03-15 | 1979-03-15 | Aromatic amine(s) from amine, hydroxyl cpd., and carbon mon-oxide - by catalytic oxidn. with oxygen or a nitro cpd. using a noble metal, selenium or sulphur catalyst |
| DEP2910132.4 | 1979-03-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1150292A true CA1150292A (en) | 1983-07-19 |
Family
ID=6065434
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000346047A Expired CA1150292A (en) | 1979-03-15 | 1980-02-20 | Preparation of aromatic urethanes |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS55124750A (en) |
| CA (1) | CA1150292A (en) |
| DE (1) | DE2910132A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0315178A2 (en) * | 1987-11-05 | 1989-05-10 | Mitsubishi Gas Chemical Company, Inc. | Process for producing a urethane and a carbonic acid ester |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3046982A1 (en) * | 1980-12-12 | 1982-07-15 | Bayer Ag, 5090 Leverkusen | METHOD FOR PRODUCING URETHANES |
-
1979
- 1979-03-15 DE DE19792910132 patent/DE2910132A1/en not_active Withdrawn
-
1980
- 1980-02-20 CA CA000346047A patent/CA1150292A/en not_active Expired
- 1980-03-14 JP JP3171780A patent/JPS55124750A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0315178A2 (en) * | 1987-11-05 | 1989-05-10 | Mitsubishi Gas Chemical Company, Inc. | Process for producing a urethane and a carbonic acid ester |
| EP0315178A3 (en) * | 1987-11-05 | 1989-08-23 | Mitsubishi Gas Chemical Company, Inc. | Process for producing a urethane and a carbonic acid ester |
| US4976679A (en) * | 1987-11-05 | 1990-12-11 | Takashi Okawa | Process for producing a urethane and a carbonic acid ester |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2910132A1 (en) | 1980-09-25 |
| JPS55124750A (en) | 1980-09-26 |
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