JPH034064B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a carbamate or a derivative thereof from an organic nitrogen compound, carbon monoxide, and an organic hydroxyl group-containing compound as defined below in the presence of a palladium-based catalyst. Carbamates are important chemicals. This is because it can be easily converted to isocyanates, which are useful and versatile raw materials for the production of polyurethanes and related compounds. Various isocyanates, especially toluene diisocyanate (TDI), via the so-called phosgene route
Much research has been carried out to develop alternatives to the well-known process of producing the most important isocyanates (and their precursor carbamates) such as methylene-4,4'-diphenyl diisocyanate (MDI). It took place over many years. On this point, see S. Ozaki's article ``Reasons, Advances, In, Isocyanates, Chemistry''[``Chem.Rev.'' Vol. 72 (1972)]
See pages 457-496]. For example, much work has been done on the reduction of aromatic nitro compounds with carbon monoxide and lower alkanols in the presence of sulfur, selenium or tellurium catalysts. A disadvantage that was considered inevitable in this process was that a small but certain amount of catalyst (particularly selenium and selenium compounds) remained in the product, and therefore the problem of this impurity could not be solved. A lot of research has been done for. Another alternative is to use compounds or complexes of group metals as catalysts together with one or more co-catalysts.
An example of this method is described in British Patent No. 1129551, in which a catalyst comprising iridium, rhodium, platinum, palladium, molybdenum or iron and a ligand is used in an excess molar amount as a co-catalyst. is disclosed for use with an amount of ferric chloride. German Published Patent No. 2903950 discloses that certain chlorides [especially iron chloride [Fe()]]
The use of cocatalyst systems based on iron oxides and/or iron oxide hydrates with iron chloride [complexes of Fe()] or hydrochlorides of tertiary amines] is disclosed. As is clear from the above-mentioned literature, the use of a co-catalyst containing a salt of a metal, such as iron, which can be present in two or more valences, is an essential condition in the known process, and this co-catalyst is present in an amount equal to or less than the amount of the main catalyst. A substantial molar excess based on the amount must be used. The use of more complex complex systems has also been proposed to overcome the substantial corrosion problems inherent in the use of ferrous or ferric chlorides. When an organic nitrogen compound, carbon monoxide, and an organic hydroxyl group-containing compound are reacted in the presence of palladium and certain types of ligands, a substantial molar excess of the cocatalyst relative to the amount of the main catalyst is present. It has now been surprisingly found that carbamates and/or their derivatives can be prepared with high selectivity without the need for the use of cocatalysts themselves as well as the use of cocatalysts. It has also surprisingly been found that the reaction rate and selectivity of this reaction step can be further increased by carrying out the reaction in the presence of an acid. The above-mentioned pronounced effect of acid addition is achieved only when the reaction is carried out according to the invention with a specific type of ligand, and it is true that the reaction is carried out according to the invention with a specific type of ligand, and it is not possible to use conventional ligands such as triphenylphosphine or pyridine. In this case, the above effect cannot be obtained. The invention therefore provides a method of combining an organic compound containing at least one hydroxyl group, carbon monoxide, an aromatic nitro compound in the presence of a catalyst system containing palladium and/or a palladium compound and a Group A ligand. In the method for producing carbamates and/or derivatives thereof by reacting the general formula (wherein each L represents a phosphorus atom; R, R ¹ , R ² and R ³ may be the same or different from each other, and each of them represents an alkyl, aryl, alkaryl or aralkyl group) and these groups may be substituted with one or more inert substituents, or R and R ¹ and/or R ² and R ³ are
Together with the atom L to which they are attached, they can also form a cyclic structure; R ⁴ and R ⁵ may be the same or different from each other, each of which carries a water atom or a lower alkyl group. n = 2, 3 or 4) or a ligand which is 2,2'-bipyridine, 1,10-phenanthroline or a derivative thereof. be. The process according to the invention has the advantage that the organic nitrogen compounds mentioned above can be completely converted to the desired carbamate with a selectivity of over 90%. Furthermore, corrosion problems and the formation of dimethyl ether by-products from methanol never occur significantly in the process of the present invention. Moreover, compared to the recovery/separation of small amounts of palladium or other group metals from large amounts of iron compounds when using multimetallic catalyst systems according to the known methods described above. , palladium recovery can be carried out much more easily with the method of the invention. Another important feature of the present invention is the ability to prepare carbamates from nitrogen compounds and CO under mild reaction conditions at high reaction rates and in high yields. From this point of view,
It can be said that the method of the present invention has great practical value. In the ligand suitable for the method of the present invention, L in the general formula () is a phosphorus atom, and R, R ¹ , R ² and
A ligand that satisfies the conditions that R ³ is the group described above, R ⁴ and R ⁵ are the same or different, each is hydrogen or a methyl group, and n = 2, 3 or 4. . In particular, L in the general formula () is a phosphorus atom, R,
R ¹ , R ² and R ³ may be the same or different from each other and each is an aryl or alkaryl group, which groups contain one or more halogen, alkoxy or aryloxy groups. It may be included as a substituent,
R ⁴ and R ⁵ may be the same or different from each other, each being a hydrogen atom or a methyl group, and it is highly preferred to use a ligand satisfying the condition that n=2, 3 or 4. The particular ligand used in the method of the invention belongs to the class of bididate ligands, i.e. it contains two heteroatoms and
It is a type of complex group or complex molecule that can form a bond with a metal through these heteroatoms. Examples of ligands in which L in the general formula () is phosphorus include the following: tetramethyldiphosphinoethane, tetramethyldiphosphinopropane, tetraethyldiphosphinoethane, tetrabutyldiphosphinoethane, Dimethyldiethyldiphosphinoethane, tetraphenyldiphosphinoethane, tetraperfluorophenyldiphosphinoethane, tetraphenyldiphosphinopropane,
Tetraphenyldiphosphinobutane, dimethyldiphenyldiphosphinoethane, diethyldiphenyldiphosphinopropane, tetratolyldiphosphinoethane, ditolyldiphenyldiphosphinoethane, tetratrifluoromethyldiphosphinotetrafluoroethane , tetraphenyldiphosphinoethane and its derivatives, 1,2-bis-(diphenylphosphino)benzene and its derivatives. Preference is given to using tetraphenyldiphosphinoethane, tetraphenyldiphosphinopropane and tetraphenyldiphosphinobutane, particular preference being given to tetraphenyldiphosphinoethane and tetraphenyldiphosphinopropane. Examples of inert substituents which may be present in the ligand of general formula () include: fluorine or chlorine atoms, alkoxy or aryloxy groups, especially methoxy or phenoxy groups; cyano groups; LRR ¹ and/or the group -LR ² R ³ (wherein L, R, R ¹ , R ² , R ³ have the meanings given above).
Additional substituents - LRR ¹ and/or groups - LR ² R ³
In the compound of general formula () having the formula (), at least two of the groups L are considered to exhibit a metal-L bond. Furthermore, 2,2'-bipyridine, 1,10-phenanthroline or derivatives thereof can also be used as ligands. As mentioned above, carbamates are prepared from aromatic nitro compounds. Examples of aromatic nitro compounds include: nitrobenzene, alkyl- and alkoxynitrobenzenes, aryl- and aryloxynitrobenzenes, dinitrobenzenes, alkyl-, alkoxy-, aryl-, and aryloxydinitrobenzenes, such as 2, 4-dinitrobenzene, 2,6-dinitrotoluene,
4,4'-dinitrodiphenylmethane; polynitrobenzene. Preferred organic nitro compounds are nitrobenzene, m-dinitrobenzene, nitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoene and 4,4'-dinitrodiphenylmethane. Surprisingly, when preparing carbamates from organic nitro compounds containing nitrogen-oxygen bonds, especially aromatic nitro compounds, when the reaction is carried out in the presence of primary or secondary amines or urea (derivatives), It has been found that even better results can be obtained. In this case, the conversion rate of the organic nitrogen compound becomes even better, and the selectivity to the desired carbamate also becomes higher. In this case, the primary or secondary amine or urea (derivative) is also co-converted to the desired carbamate. Primary amines of the general formula R ⁶ NH ₂ (where R ⁶ represents a substituted or unsubstituted alkyl, aryl, alkaryl, aralkyl or cycloalkyl group) can advantageously be used. Preference is given to using primary amines containing up to 14 carbon atoms, and particular preference to using aromatic primary mono- and diamines containing 6 to 13 carbon atoms, examples of which include aniline, p-amino toluene, 2,4-diaminotoluene, 2,6-diaminotoluene and 4,
Examples include 4'-methylene dianiline. Very good results were obtained using aniline as co-reactant. It has been found that the presence of primary amines can lead to the formation of urea derivatives. For example, nitrobenzene, carbon monoxide, and methanol are combined in the presence of aniline at a relatively low temperature (e.g., 90°C).
When the reaction is carried out at a temperature of 120 DEG C., large amounts of 1,3-diphenylurea are produced, which can be isolated as such. When the reaction temperature is raised to 130 DEG-150 DEG C., the 1,3-diphenylurea thus formed is quantitatively converted to the desired carbamate. Careful control of the reaction conditions also provides the advantage of being able to adjust the ratio of urea derivative and carbamate products accordingly. Urea (derivatives) can also be used as co-reactant in the method of the invention. Examples of suitable urea derivatives include: dialkyl- and diarylureas, especially symmetrical diarylureas such as diphenylurea, di-p-tolylurea, especially diphenylurea. The first compound used together with the organic nitrogen compounds already mentioned.
Alternatively, the amount of secondary amine or urea (derivative) used has no critical conditions and can be varied within a wide range. This amine or urea (derivative)
and the organic nitrogen compound in a molar ratio of 1:10 to 1:1.
Preferably, the ratio is 10:1. As already mentioned, the method of the present invention involves reacting an organic nitrogen compound, carbon monoxide, and an organic compound containing at least one hydroxyl group.
Monohydric or polyhydric alcohols containing primary, secondary or tertiary hydroxyl groups can be used, and also mixtures of these compounds. An organic compound containing at least one hydroxyl group may, for example, have the general formula R ⁷ (OH) _n (where m is an integer of 4 or less and R ⁷ has up to 20 carbon atoms, preferably up to 6 carbon atoms). (representing a substituted or unsubstituted alkyl group, aryl group, alkaryl group or aralkyl group). Examples of compounds of the general formula R ⁷ (OH) _n (where m and R ⁷ have the meanings given above) include monohydric alcohols such as methanol, ethanol, n-propanol, 2-propanol, butanol, amyl alcohol, hexyl alcohol, lauryl alcohol, acetyl alcohol, benzyl alcohol, chlorobenzyl alcohol, methoxybenzyl alcohol, methoxyethanol, butoxyethanol, cyclohexyl alcohol, phenol, cresol. Examples of polyhydric alcohols include: diols such as ethylene glycol, diethyl glycol, propylene glycol, dipropylene glycol; triols such as glycerol, trimethylolpropane, hexanetriol. Ethers of polyhydric compounds can also be used. However, this ether must contain at least one free hydroxyl group in its molecule. Preference is given to using lower alcohols, examples of which include methanol, ethanol, propanol, isopropanol, butanol, sec-butanol, isobutanol, ethylene glycol, glycerol,
Mention may be made of trimethylolpropane, but methanol and ethanol are particularly preferred. There are no critical conditions for the ratio of organic nitrogen compound to hydroxyl group-containing compound. This is because in the method of the present invention, any one of these compounds can be used in excess and the surplus can be used as a solvent. Although it has been found advantageous to carry out the process of the invention in the presence of a (large) excess of the organic hydroxyl-containing compound, it is of course also possible to use an excess of the given organic nitrogen compound. . The process according to the invention can also be carried out in the presence of inert diluents, examples of which include: aliphatic or aromatic hydrocarbons such as hexane, benzene, toluene; Halogenated hydrocarbons such as perfluoroalkanes; ketones, esters, ethers. The process of the invention is carried out in the presence of a palladium-based catalyst. Palladium can be used as is, supported on an inert carrier such as carbon or alumina. Alternatively, palladium can be used in the form of palladium compounds, especially palladium salts. Good results are also obtained when using palladium compounds that are substantially soluble in the main reaction mixture. Examples of useful palladium salts include: palladium chloride, palladium bromide, palladium iodide, sodium tetrachloropaldate, potassium tetrachloropaldate, potassium tetraiodopaldate, palladium acetate, propionic acid. Palladium, palladium isobutyrate, palladium acetylacetate and similar palladium compounds. Preference is given to using palladium salts of organic acids, palladium acetate being particularly preferred. It will be appreciated that the presence of palladium and/or a palladium compound together with the compound of general formula () is an essential condition in order to obtain the desired carbamate with high selectivity and high yield. The amount of palladium or palladium compound used in the process of the invention is preferably 0.001-10% by weight, more preferably 0.005-3% by weight (based on the weight of nitrogen compounds present in the reaction compound).
Preferably, the palladium compound is used in relatively small amounts, for example less than 0.5% by weight (based on the weight of the nitrogen compound present in the reaction mixture). Surprisingly, it has been found that the use of a cocatalyst is unnecessary even when using only small amounts of palladium compounds. Regarding the amount of the compound of general formula () used, it is advantageous to use it in such an amount that the ratio of palladium (compound) to the compound of general formula () is from 0.05 to 50, preferably from 0.1 to 20. be. As already mentioned, the reaction is preferably carried out in the presence of an acid, which serves to increase the conversion of the organic nitrogen compound and in most cases also to increase the selectivity to the desired carbamate. If the atom L of the ligand is phosphorus, arsenic or antimony, preference is given to using acids with a pKa>3.5, especially carboxylic acids. Preferred acids are
Organic acids with pKa>3.5, especially carboxylic acids. Carboxylic acids containing 1-6 carbon atoms, especially acetic acid, are preferred. When the atom L of the ligand is nitrogen, the pKa
Preferably, acids with <3.5 are used. This is because in this case, a relatively strong acid has a greater effect on increasing the reaction rate than an acid with a pKa<3.5. Although hydrogen halides such as HCl can be used, acids with pKa<3.5 and free of halogen anions are more preferred. Hydrogen halides have relatively low activity as promoters and can cause equipment corrosion problems. Examples of suitable halogen anion-free acids include: sulfuric acid, phosphoric acid, perchloric acid, fluorosilicic acid, fluorosilicic acid, fluorosulfonic acid. Sulfonic acids of the formula R ⁸ SO ₃ H (wherein R ⁸ represents a substituted or unsubstituted hydrocarbon group) are particularly preferred. The hydrocarbon group may be an alkyl, aryl, aralkyl or alkaryl group containing 1 to 30 carbon atoms, preferably 1 to 14 carbon atoms. This hydrocarbon group may be substituted, for example, with a halogen atom (particularly a fluorine atom). Preferred sulfonic acids are p-toluenesulfonic acid and trifluoromethylsulfonic acid. The acid R ⁸ SO ₃ H may also be an ion exchange resin containing sulfonic acid groups, an example of which is Amberlite 252H, in which case the group R ⁸ is a polymeric hydrocarbon group, such as a sulfonic acid group. Group substitution - can be a polystyrene group. The amount of acid present in the reaction mixture is preferably 0.01−
150 equivalents, more preferably 0.1-100 equivalents, most preferably 1-50 equivalents (per gram atom of palladium). The carboxylic acid such as acetic acid is preferably used in an excess amount (based on the molar amount of the compound of general formula ()). The process according to the invention is advantageously carried out at temperatures below 300°C. The reaction temperature is preferably 75-200°C, more preferably 85-150°C. This reaction can generally be carried out at pressures above atmospheric pressure, pressures up to 500 bar can be applied. Preferably, the process of the invention is carried out under relatively low pressure. Good results are obtained when the initial pressure is 30-70 bar. Mixtures of carbon monoxide and hydrogen with a hydrogen content of up to about 20% by weight can also be used. The presence of hydrogen allows the formation of amines from organic nitrogen compounds (in situ formation), in particular the formation of aniline from nitrobenzene, which can then be converted to the desired carbamate. The method of the present invention is particularly useful for producing monocarbamates or derivatives thereof by reacting a mononitro, mononitrone, monoazo, or monoazoxy compound with carbon monoxide and an organic monohydroxy compound. Furthermore, the method of the present invention provides for producing polycarbamates or derivatives thereof by reacting polynitro, polynitrone, nitro-substituted azo or nitro-substituted azoxy compounds (preferably 2,4-dinitrotoluene) with carbon monoxide and organic monohydroxy compounds. This is a particularly useful manufacturing method in some cases. The operation of the process according to the invention can be carried out batchwise, semi-continuously or continuously. Reaction times will of course vary in relation to temperature and pressure. Generally, a reaction time of about 1 to 20 hours will be sufficient. The carbamates produced by the process of the invention can be used as such, for example as starting materials in the production of agricultural chemicals, dyes, pharmaceuticals or polyurethanes, or they can be reacted to by methods known in the art. Can be converted to isocyanate. A suitable conversion method is to heat the carbamate. Therefore, the present invention provides a compound obtained by reacting an organic nitrogen compound, carbon monoxide, and an organic compound having at least one hydroxyl group in the presence of a catalyst system containing palladium and a ligand of the general formula (). The present invention also provides a method for producing organic isocyanates by converting carbamates and/or derivatives thereof. EXAMPLES In order to more specifically illustrate the present invention, Examples are shown below. However, the scope of the present invention is by no means limited to the scope described in these Examples. As will be readily understood by those skilled in the art, the operating conditions of the method of the present invention may vary. Example 1 Nitrobenzene (7.5 ml), methanol (50 ml), palladium acetate (0.7 mmol) and tetraphenyldiphosphinoethane (4 mmol) were placed in a 300 ml autoclave (made of Hastelloy C alloy). The autoclave was then pressurized with carbon monoxide (initial pressure 40 bar). Temperature 135℃
The reaction mixture was kept at this temperature for 15 hours.
The reaction mixture was then cooled and then analyzed by gas-liquid chromatography. The conversion of nitrobenzene was 60%, the selectivity to methyl carbanilate was 82%, and the selectivity to aniline was 18%. This experiment was repeated, but this time the amount of tetraphenyl diphosphinoethane used was doubled. In this case, the conversion rate of nitrobenzene was 85% and the selectivity to methyl carbanilate was 80%. Example 2 The experiment described in Example 1 was repeated, but this time using 4 mmol of tetraphenyldiphosphinoethane.
The reaction was then carried out in the presence of acetic acid (10 mmol). The conversion rate of nitrobenzene was 95%, the selectivity to methyl carbanilate was 92%, and the conversion rate to aniline was 8%. Example 3 The experiment described in the previous example was repeated, but this time the amount of nitrobenzene used was reduced (2.5 ml). Gas-liquid chromatography data showed complete conversion of nitrobenzene with 92% selectivity to methyl carbanilate. Example 4 The experiment described in Example 3 was repeated, but this time 1 g of Pd/C (5% by weight) was used instead of palladium acetate. The reaction was carried out under the same conditions except for
The conversion of nitrobenzene was 30% and the selectivity to methyl carbanilate was 90%. Further experiments were conducted, and in the case of Pd/C (5
wt%) 1 g, tetraphenyldiphosphinopropane (0.7 mmol) and acetic acid (16 mmol)
It was used. Conversion of nitrobenzene after 5 hours is 98%, selectivity to methyl carbanilate is 97%
It was hot. Example 5 The experiment described in Example 2 was repeated, but this time 2,4-dinitrotoluene (5
(g, water content 50% by weight was used as is). The other conditions were the same, but
The 2,4-dinitrotoluene was found to be completely converted. There were only two products, the desired carbamate and the intermediate aminocarbamate, in a ratio of about 1. Example 6 In an autoclave (made of Hastelloy C alloy), nitrobenzene (7.5 ml), methanol (50 ml), palladium acetate (0.7 mmol), tetraphenyldiphosphinoethane (4 mmol) and acetic acid (2% by weight; nitrobenzene and methanol (total amount standard) was included. The autoclave was then pressurized with carbon monoxide (initial pressure 60 bar). Temperature 135℃
The reaction mixture was kept at this temperature for 15 hours.
The reaction mixture was cooled and then analyzed by gas-liquid chromatography. The conversion rate of nitrobenzene was 95% and the conversion rate to methyl carbanilate was 92%. Example 7 The experiment described in the previous example was repeated, but this time the amount of palladium acetate used was reduced by a factor of 10 (0.006 mmol), and the amount of tetraphenyldiphosphinopropane used was similarly reduced (0.36 mmol). mmol). Furthermore, the reaction time was shortened to 5 hours. The conversion of nitrobenzene was 50% and the selectivity to methyl carbanilate was 97%. Example 8 The experiment described in the previous example was repeated, but this time also in the presence of aniline (2 ml). The conversion of nitrobenzene was 70% and the conversion of aniline was 80%. Both nitrobenzene and aniline were converted to methyl carbanilate with almost 100% selectivity. No other products were observed. Example 9 The experiment described in Example 7 was repeated, but this time the amount of palladium acetate used was reduced by half (0.033 mmol) and the amount of tetraphenyldiphosphinopropane used was also reduced by half (0.18 mmol). The autoclave was pressurized with carbon monoxide and hydrogen (initial pressure: 52 bar carbon monoxide; 8 bar hydrogen).
Conversion of nitrobenzene was 84%, selectivity to methyl carbanilate was 70%, and the remainder of the product was aniline. This experiment was repeated further, but this time the amount of tetraphenyl diphosphinopropane used was reduced by a factor of 4 (0.045 mmol). The conversion rate of nitrobenzene is 95%,
The selectivity to methyl carbanilate was 70%. Example 10 In an autoclave (made of Hastelloy C alloy),
Add 4-dinitrotoluene (5 g; used as is with water content of 50%), aniline (4 ml), methanol (50 ml), palladium acetate (0.033 mol), and tetraphenyldiphosphinopropane (0.045 mmol). Pressurized with carbon monoxide (initial pressure
60 bar). The temperature was raised to 135°C and the reaction mixture was kept at this temperature for 5 hours. According to gas-liquid chromatography analysis, the conversion of 2,4-dinitrotoluene was 95% and the conversion to aniline was 60%. Thus, the conversion of 2,4-dinitrotoluene to dicarbamate was carried out with a conversion rate of 70%, and the conversion to aminocarbamate was carried out with a selectivity of 30%. Aniline was converted to methyl carbanilate with almost 100% selectivity. . Example 11 The experiment described in Example 10 was repeated, but this time the temperature was
The temperature was 110° C. and nitrobenzene (7.5 ml) and aniline (4 ml) were used as raw materials. According to gas-liquid chromatography analysis, the original amount of aniline was completely converted and 1,3-diphenylurea was obtained in high yield (90%, based on aniline). Methyl carbanilate was obtained in a yield of 60% (based on nitrobenzene; conversion of nitrobenzene approximately 70%). The reaction temperature was then increased to 135°C and the reaction continued at this temperature for an additional 5 hours. The total conversion of nitrobenzene was 90%, and an additional amount of methyl carbanilate was obtained, which corresponded to the amount of 1,3-diphenylurea produced by the conversion. Ta. Example 12 The experiment described in Example 4 was repeated, but this time Pd/C
(5% by weight) 1g, tetraphenyldiphosphinopropane (0.17 mmol), acetic acid (16 mmol)
and aniline (2 ml) were used. After 5 hours, the nitrobenzene was completely converted and the aniline conversion was 50%. Both nitrobenzene and aniline were converted to methyl carbanilate. No other products were observed. Example 13 An autoclave (made of Hastelloy C alloy) was charged with nitrobenzene (7.5 ml), methanol (50 ml), palladium acetate (0.1 mmol), 2,2'-bipyridine (4 mmol) and acetic acid (8 mmol). The autoclave was then pressurized with carbon monoxide (initial pressure 60 bar). The temperature was raised to 135°C and the reaction mixture was kept at this temperature for 5 hours. The reaction mixture was cooled and then analyzed by gas-liquid chromatography. The conversion of nitrobenzene was 66% and the selectivity to methyl carbanilate was 80%. Azoxybenzene was observed as a by-product. Example 14 The experiment described in the previous example was repeated, but this time 1,10-phenanthroline (4 mmol) was used instead of 2,2-bipyridine. The conversion of nitrobenzene was 98% and the selectivity to methyl carbanilate was 91%. Aniline (5%) and azobenzene (4%) were observed as by-products. Example 15 The experiment described in the previous example was repeated, but this time also in the presence of aniline (2 ml). The conversion rate of nitrobenzene is 100%,
The conversion rate of aniline was 10%. The selectivity to methyl carbanilate based on converted starting material was 94%. The only by-product recognized was azobenzene. Example 16 The experiment described in Example 14 was repeated, but this time also in the presence of triethylamine (3 ml). The conversion of nitrobenzene was 100%. Azobenzene (63%) was found to be the main product and with it methyl carbanilate (37%). Example 17 The experiment described in Example 15 was repeated, but this time the reaction temperature was 115°C. 1,3-diphenylurea was obtained in a yield of 3.3 g, and with it methyl carbanilate in a yield of 80% (based on the amount of nitrobenzene used). The experiment described in Example 15 was then repeated again, except that 1,3-diphenylurea (2 g) was used instead of aniline, but in this case the conversion of nitrobenzene was 95% and the methyl carbamate The selectivity to nylate was 100%. And 1,3
- Diphenylurea was converted to methyl carbanilate and aniline. Example 18 A 300 ml autoclave (made of Hastelloy C alloy) was charged with nitrobenzene (7.5 ml), methanol (50 ml), palladium acetate (0.033 mmol), and the amounts of ligand and acid listed in Table A.
The autoclave was then pressurized with carbon monoxide (initial pressure 60 bar). The temperature was raised to 135°C and the reaction mixture was kept at this temperature for the specified time (see Table A). The reaction mixture was cooled and then analyzed by gas-liquid chromatography. Conversion rate of nitrobenzene, selectivity to methyl carbanilate, reaction rate [g (methyl carbanilate)/g (Pd)/
] were as listed in Table A. Comparative experiments were also conducted, and the results showed that when a ligand other than the one used in the present invention (i.e., triphenylphosphine, tetraphenyldiphosphinemethane, tributylphosphine, or pyridine) was used, It was found that little or no methyl carbanilate was formed even in the presence of acid cocatalysts. Furthermore, Experiments 9, 10, 12 and
In No. 13, the amount of palladium acetate used was 0.7 mmol instead of 0.033 mmol.

[Table] Example 19 The experiment described in Example 18 was repeated, but this time nitrobenzene (7.5 ml), methanol (50 ml), palladium in vinegar (0.033 mmol), aniline (4 ml), 1,
10-phenanthroline (1.5 mmol) and p
-Toluenesulfonic acid (0.33 mmol) was used. After 3 hours of reaction time, the conversions of nitrobenzene and aniline are 93% and 50%, respectively, and the yield of methyl carbanilate is
It was 60%. Furthermore, about 4 g of 1,3-diphenylurea was obtained. Example 20 The experiment described in Example 19 was repeated, but this time using 2 g of 1,3-diphenylurea instead of 4 ml of aniline. After a reaction time of 3 hours, the conversion of both nitrobenzene and 1,3-diphenylurea is 100%, and the selectivity to methyl carbanilate and aniline is 90% and 10%, respectively.
It was hot.

Claims (1)

[Claims] 1. An organic compound containing at least one hydroxyl group, carbon monoxide, and an aromatic nitro compound in the presence of a catalyst system containing palladium and/or a palladium compound and a Group A ligand. In the method for producing carbamates and/or derivatives thereof by reacting the general formula (wherein each L represents a phosphorus atom; R, R ¹ , R ² and R ³ may be the same or different from each other, and each of them represents an alkyl, aryl, alkaryl or aralkyl group) and these groups may be substituted with one or more inert substituents, or R and R ¹ and/or R ² and R ³ are
Together with the atom L to which they are attached, they can also form a cyclic structure; R ⁴ and R ⁵ may be the same or different from each other, each of which carries a hydrogen atom or a lower alkyl group. n = 2, 3 or 4) or a ligand which is 2,2'-bipyridine, 1,10-phenanthroline or a derivative thereof. 2 A patent in which R, R ¹ , R ² and R ³ of the ligand of general formula () are phenyl groups, L is phosphorus, R ⁴ and R ⁵ are hydrogen, and n is 2, 3 or 4 The method according to claim 1. 3. The method according to claim 2, wherein the ligand is tetraphenyldiphosphinoethane or tetraphenyldiphosphinopropane. 4 Primary or secondary amine or urea (derivative)
The method according to any one of claims 1 to 3, wherein the reaction is carried out in the presence of. 5. The method according to any one of claims 1 to 4, wherein the reaction is carried out in the presence of an acid. 6. The method according to claim 5, wherein the reaction is carried out in the presence of an acid with a pKa>3.5. 7. The method of claim 6, wherein the acid is a carboxylic acid containing 1-6 carbon atoms. 8. The method according to claim 7, wherein the reaction is carried out in the presence of an acid with a pKa<3.5. 9. Patents in which the acid is a sulfonic acid R ⁸ SO ₃ H (where R ⁸ represents an alkyl group having 1 to 30 carbon atoms, preferably 1 to 14 carbon atoms, an aryl group, an aralkyl group or an alkaryl group) The method according to claim 8. 10. The method according to claim 9, wherein the acid is p-toluenesulfonic acid or trifluoromethylsulfonic acid. 11 The amount of acid present in the reaction mixture is 0.01-150 equivalents, preferably 0.1-100 equivalents, more preferably 1
-50 equivalents (per gram atom of palladium). 12. Process according to any one of claims 1 to 11, wherein the reaction is carried out at a temperature of 75-200°C, preferably 85-150°C. 13. Process according to any one of claims 1 to 12, wherein the reaction is carried out under a pressure of less than 500 bar.