JPS61191664A - Production of aryl aromatic carbamate - Google Patents

Abstract

PURPOSE:The reaction between a aromatic nitro compound, an aromatic hydroxy compound and carbon monoxide is conducted in the presence of a novel catalyst to give the objective compound which is used as a feedstock for agricultural chemicals, isocyanates and polyurethane in high yield with good operability. CONSTITUTION:The reaction between an aromatic nitro compound, an aromatic hydroxy compound and carbon monoxide is carried out in the presence of a catalyst of metallic palladium or a palladium compound, in addition, a cocatalyst of a specific combination of a phosphorus halide, an inorg compound and a tertiary amine, in a solvent such as benzene at 160-220 deg.C under a carbon monoxide-partial pressure of 100-500kg/cm<2>G for 10min-10hr to give the objective compound. EFFECT:Since the catalyst according to the present invention is extremely reduced in its corroding properties, inexpensive usual materials may be employed for the react.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing an aromatic carbamic acid aryl ester useful as a raw material for agricultural chemicals, isocyanates, or polyurethanes.

More specifically, the present invention relates to a method for producing an aromatic carbamic acid aryl ester from an aromatic nitro compound, an aromatic hydroxy compound, and carbon monoxide using a novel catalyst system.

[Conventional technology]

Monoaromatic isocyanates are generally produced by reacting aromatic amines obtained by reducing aromatic nitro compounds with phosgene. In recent years, new methods for producing isocyanates have been developed due to the lack of raw material resources, soaring prices, and the strong toxicity of intermediate raw materials such as phosgene.

One of these methods involves reacting an organic nitro compound with carbon monoxide and an organic hydroxy compound to produce the corresponding carbamic acid ester, which is then decomposed into an isocyanate and an organic hydroxy compound.

In this case, when an alcohol is used as the organic hydroxy compound, an aromatic carbamic acid alkyl ester can be obtained.

Aromatic carbamic acid alkyl esters generally have a high decomposition temperature, and when attempting to obtain aromatic isocyanates by thermal decomposition, a high temperature of 250°C or higher is usually required to obtain an effective reaction rate for industrial implementation. This causes many problems such as deterioration of raw materials and products, decrease in yield, and increase in utility costs.

On the other hand, aromatic carbamic acid aryl esters obtained using aromatic hydroxy compounds as organic hydroxy compounds can be thermally decomposed at relatively low temperatures, which alleviates the above-mentioned problems in the thermal decomposition process. This is extremely advantageous compared to using it as a raw material.

However, the conventional method for producing aromatic carbamic acid aryl ester from an aromatic nitro compound, an aromatic hydroxy compound, and carbon monoxide has various problems.

For example, Japanese Patent Publication No. 56-12,632 describes a method for producing aromatic carbamic acid esters using a catalyst consisting of palladium, ruthenium or rhodium, a Lewis acid, and a tertiary amine, but uses phenol as the hydroxy compound. The reaction rate is lower and the yield is lower than when alcohol is used.

Moreover, the reaction liquid becomes a slurry, making separation and purification of the catalyst and reactants troublesome.

In addition, Japanese Patent Publication No. 43-23-939 describes a method for producing aromatic carbamic acid esters in the presence of a carbonyl-containing derivative of a group I metal of the periodic table such as rhodium as a catalyst and a co-catalyst such as ferric chloride. However, when phenol is used as the hydroxy compound, the yield is significantly lower than when alcohol is used.

In addition, U.S. Pat. No. 3,531,512 (1970) proposes a method using palladium and a Lewis acid as a catalyst, but this method also has a low yield when phenol is used, and it also It is extremely corrosive to diferrous iron, stainless steel, etc., making it difficult to put it into practical use.

Furthermore, as a method for producing an aromatic carbamic acid ester with an improved catalyst system, a method using a catalyst consisting of metal palladium or a palladium compound, vanadium oxytrichloride, and a tertiary amine (Japanese Patent Application Laid-Open No. 54-22-339), A method in which a platinum group metal and/or its compound is used as a main catalyst and a Lewis acid and an oxide of a group Va or Vla metal of the periodic table such as vanadium are used as a co-catalyst (Japanese Patent Application Laid-Open No. 128-128-550)
, a method using a catalyst consisting of metallic palladium or a palladium compound, an iron compound, a bicyclic amidine, and a halogen compound has been reported (Japanese Patent Application Laid-open No. 57-32-251), and phenols are used as usable hydroxy compounds. Although they are listed, specific examples are not mentioned.

The present inventors investigated the production of aromatic carbamic acid aryl esters from aromatic nitro compounds, aromatic hydroxy compounds, and carbon monoxide, and found that the conventional method using alcohol could be used as is in place of aromatic hydroxy compounds. So, even if a highly active catalyst is used to produce an aromatic carbamic acid alkyl ester, there may be problems such as a decrease in the reaction rate and yield of the desired product, deterioration in the operability of the catalyst-reaction liquid, and the material of the reactor. It turns out that many problems arise.

[Problem that the invention seeks to solve]

The present invention has been made based on the above-mentioned viewpoints, and is capable of producing aromatic carbamic acid aryl esters from aromatic nitro compounds, aromatic hydroxy compounds, and carbon monoxide in good yields using a new catalyst system. Another object of the present invention is to provide a manufacturing method with good operability.

[Means to solve the problem]

The present inventors have completed the present invention as a result of intensive studies to achieve the above-mentioned objectives. That is, the present invention provides a method for producing an aromatic carbamic acid aryl ester by reacting an aromatic nitro compound, an aromatic hydroxy compound, and carbon monoxide in the presence of a catalyst. This is a method for producing an aromatic carbamic acid aryl ester, which is characterized by carrying out the reaction at high temperature and high pressure using a catalyst system consisting of a phosphorus compound, an iron compound, and a tertiary amine.

According to the method of the present invention, aromatic carbamic acid esters, which can be easily thermally decomposed under mild conditions to obtain the corresponding isocyanates in high yields, can be produced at a higher reaction rate than in conventional methods. Can be produced with high yield.

Furthermore, since the catalyst metal component is extremely small compared to conventional methods, the catalyst component is well melted, and the reaction liquid does not substantially become a slurry, making it easy to handle.

Furthermore, material corrosion is less than in conventional methods, and equipment made of normal industrial materials can be used.

The aromatic nitro compound used as the main raw material in the method of the present invention is an aromatic compound having at least one nitro group as a nuclear substituent, and the number of nitro groups may be one or two or more. . That is, it may be a mononitro compound or a polynitro compound. Further, the aromatic compound may contain a substituent other than a nitro group.

For example, these include nitrobenzenes, dinitrobenzenes, dinitrotoluenes, nitronaphthalenes, nitroanthracenes, nitrobiphenyls, bis-trophenyl) alkanes, bis-trophenyl) ethers, bis-trophenyl) ) thioethers, bistrophenyl) sulfones, nitrodiphenoxyalkanes,
Examples include nitrophenothiazines and heterocyclic compounds such as 5-nitropyrimidine. Specific compounds include nitrobenzene, o-, m- and p-nitrotoluene, 0-nitro-p-xylene, 1-nitronaphthalene, m- and p-dinitrobenzene, 2.4- and
．． 6-sinitrotoluene, dinitromesitylene, 4.4
'-Dinitrobiphenyl, 2,4-dinitrobiphenyl, 4,4'-dinitrodibenzyl, bis(4-nitrophenyl)methane, bis(4-nitrophenyl)ether, bis(2+4-dinitrophenyl)ether, bis(
4-nitrophenyl)thioether, bis(4-nitrophenyl)sulfone, bis(4-nitrophenoxy)ethane, α,α′-dinitro p-xylene, α,αl-
Dinitro m-xylene, 2.4.6-1-linitrotoluene, O-, m- and p-chloronitrobenzene, 2
, 3-13.4- and 2.5-dichloronitrobenzene, 1-chloro-2,4-dinitrobenzene, 1-bromo-4-nitrobenzene, 1-fluoro-2,4-dinitrobenzene, O-, m- and p-nitrophenyl carbamate, o-, m- and p-nitroanisole, 2,4
-dinitrophenylur, ethyl p-nitrobenzoate,
Examples include m-nitrobenzenesulfonyl chloride, 3-nitrophthalic anhydride, 3,3'-dimethyl-4,4'-dinitrobiphenyl, 1,5-dinitronaphthalene, and isomers of these aromatic nitro compounds or Mixtures can also be used, as can homologs. Also,
Aromatic nitroso compounds, azo, and azoxy compounds can also be used as well as aromatic nitro compounds.

The aromatic hydroxy compounds used in the present invention include monovalent and polyvalent monocyclic and polycyclic aromatic hydroxy compounds. Further, these aromatic hydroxy compounds may be substituted with a substituent inert to this reaction, such as a monovalent substituent such as an alkyl group, a halogen atom, or a carboxylic acid ester group, or may be substituted with an alkylene group, an oxy group, It may be crosslinked with a divalent group such as a sulfinyl group, a sulfonyl group, or a carbonyl group.

For example, phenol, chlorophenol, cresol, ethylphenol or alkylphenols such as linear or branched propylphenol, butyl and higher nonylphenols, catechol, resorcinol, pyrogallol, phloroglucinol, α-naphthol, β-
Naphthol, anthranol, phenanthrol, 4.
Examples include 4'-dihydroxydiphenylmethane and 2,2'-isopropylidene diphenol.

The amount of these aromatic hydroxy compounds used must be at least in an equimolar ratio to the nitro group of the aromatic nitro compound. If the molar ratio is less than the equimolar ratio, the reaction becomes slow and the yield of the target aromatic carbamic acid aryl ester decreases. Furthermore, using the aromatic hydroxy compound in a large excess relative to the aromatic nitro compound is not only not economically advisable but also tends to lower the yield. It is usually used in a molar ratio of 1 to 10, preferably 1 to 5 molar relative to the nitro group of the aromatic nitro compound. In addition, the amount of aromatic hydroxy compound used in the total raw material liquid is 5 to 85%.
wt%, preferably 10 to 75 wt%.

In the method of the present invention, metal palladium or a palladium compound is used as the main catalyst, including simple metals such as baladilum black, halides, cyanides, thiocyanides,
Addition compounds or complexes with isocyanides, oxides, sulfates, nitrates, organic acid salts such as acetic acid, carbonyl compounds, tertiary amines such as triethylamine, pyridine, isoquinoline, or organic phosphorus compounds such as triphenylphosphine. Examples include complexes, divalent or zero-valent palladium complexes coordinated with neutral ligands such as carbon monoxide, and the like. Reactions also occur with noble metals other than palladium, such as platinum, ruthenium, rhodium, and iridium, and aromatic carbamic acid aryl esters are produced, but in very small quantities, making industrial use difficult.

If these can be used as they are in the reaction, they can be used as carriers such as alumina, silica, silica alumina, carbon, barium sulfate, calcium carbonate, asbestos, bentonite, diatomaceous earth, Fuller's earth, organic ion exchange resin, inorganic ion exchange resin, silicic acid. It may be supported on magnesium, zeolite, aluminum silicate, molecular sieve, or the like.

Furthermore, these carriers may be charged into the reactor separately from palladium or their compounds.

The amount of palladium used for the nitro compound can vary widely depending on the type and other reaction conditions;
1 to 1 in weight ratio as a single metal to the nitro compound
x 104, preferably 5 x 10' to 5 x 10''''4
Used within the range of

The process of the present invention is characterized by the use of a co-catalyst system consisting of a combination of a special compound consisting of a halogenated phosphorus compound, an iron compound and a tertiary amine in addition to the main catalyst palladium or its compound.

In order to carry out the method of the present invention effectively, the use of each catalyst component is essential, but the addition of halogenated phosphorus compounds is particularly effective, increasing the activity of the catalyst system and promoting the reaction. Suppresses the formation of by-products and increases the selectivity of the target product.

Examples of the halogenated phosphorus compounds used in the method of the present invention include phosphorus trifluoride, phosphorus trichloride, phosphorus tribromide, phosphorus triiodide, phosphorus pentafluoride, phosphorus pentachloride, phosphorus pentabromide, and phosphorus tetrabromide. Phosphorus halide compounds such as niline chloride and niline tetraiodide; alkyl- or aryl-substituted phosphorus halide compounds such as dimethylbromophosphine, diphenylchlorophosphine, and ethylphosphorus tetrachloride; phosphozyl fluoride, phosphoryl chloride, phosphoryl bromide, - Phosphorus oxyhalides such as phosphoryl difluoride chloride, phosphodyl dichloride-fluoride, pyrophosphoryl chloride, and phosphorus oxyhalide; Quaternary phosphonium halides such as tetraethylphosphonium chloride; Phosphonyl halides such as ethylphosphonate dichloride ; Examples include alkyl phosphate halogenides such as methyl phosphate dichloride.

These halogenated phosphorus compounds are palladium 1
From 0.05 to 20 gram atoms of phosphorus are used per gram atom, preferably from 0.1 to 10 gram atoms. Also, for 1 mole of raw material nitro compound, IX 10-3
The concentration in the reaction solution is preferably I x 10-' g or more per 1 kg of the total reaction solution.

Examples of iron compounds include iron halides such as ferrous chloride, ferric chloride, ferrous bromide, and ferric bromide, dichlorotris (2
,2'-bipyridyl)iron, tetrabromo(tetraethylammonium)iron, tetrachloro(tetraethylammonium)iron, tetrachlorohis(tetraethylammonium)iron, dichlorotetrapyridineiron, iron complexes containing halogens and bases, ferrous acetate. , carboxylates such as ferric acetate and ferrous oxalate, oxides such as ferrous oxide, ferric oxide, and triiron tetroxide, iron trihydroxide, iron monoxide hydroxide, and water. Examples include hydroxides such as iron diacetate oxide, ferrates such as potassium iron tetroxide, iron tris(acetylacetone), ferric nitrate, and iron chloride oxide.

The iron component is added to the reaction system as a metal or as at least one compound selected from oxides, hydroxides, carbonyl compounds, and organic complex compounds. Examples of iron organic complex compounds include ferrocene, iron acetylacetonate,
Examples include iron acetylide, iron porphyrin, and iron phthalocyanine.

The amount of iron component used is usually 0.1 to 100 gram atoms as metal per 1 gram atom of palladium, preferably 0.
．． 2 to 10 gram atoms and a molar ratio of I
The molar ratio is from X 10-3 to I X 10-1. If the amount of this iron component used is too small, the expected catalytic activity cannot be obtained, and if it is too large, not only will the yield of the desired product decrease, but also the treatment of the mixture after the reaction will be troublesome, which is undesirable. .

As the tertiary amine, aliphatic, aliaromatic, alicyclic, aromatic tertiary amines and nitrogen-containing heterocyclic compounds are used. If these may be in unsubstituted form, suitable substituents inert to this reaction may be used, such as halogen atoms, alkyl groups, aryl groups, alkenyl groups, cyano groups, aldehyde groups, alkoxy groups, phenoxy groups, alkylthio groups, It may have a substituent such as a phenylthio group, a carbamyl group, a carbalkoxy group, or a thiocarbamyl group.

These include, for example, aliphatic tertiary amines such as trimethylamine, triethylamine, tripropylamine, and tributylamine, N,N-dimethylaniline, N,N-
Fatty aromatic amines such as diethylaniline, N,N-diisopropylaniline, N,N-dimethylcyclohexylamine, N,N-diethylcyclohexylamine, N,N-diisopropylcyclohexylamine, 1,
4-Diazabicyclo (includes alicyclic tertiary amines such as 2,2,23 octane, aromatic tertiary amines such as triphenylamine, and nitrogen-containing heterocyclic compounds such as pyridine, quinoline, and isoquinoline) Among them, nitrogen-containing heterocyclic compounds are particularly effective in improving the yield and reaction rate of urethane. Examples of effective nitrogen-containing heterocyclic compounds other than those mentioned above include l-methylpyrrole, 1 -phenylpyrrole, 1-methylimidazole, l
-Methylindole, 1-phenylindole, indolenine, 2-isobenzazole, indolizine, 1-methylcarbazole, 2-chloropyridine, 2-bromopyridine, 2-fluoropyridine, 4-phenylpyridine, 2-, 3 -, and 4-methylpyridine, 2-methyl-
5-ethylpyridine, 2,6-dimethylpyridine, 2.
4.6-drimethylpyridine, 2-vinylpyridine, 2
-Styrylpyridine, 3-chloropyridine, 2,6-dichloropyridine, 2-chloro-4-methylpyridine, 4
-Phenylthiopyridine, 2-methoxypyridine, 4-
Dimethylaminopyridine, α-picolinate phenyl ester, γ-picolinate methyl ester, 2,6-dicyatubiridine, α-picolinaldehyde, α-picolinamide, 5,6,7,8-tetrahydroquinoline, 2.2
'-Dipyridyl, 2-chloroquinoline, acridine, phenanthridine, benzoquinoline, benzisoquinoline, naphthyridine, pyrazine, 4.6-dimethylpyrazine, 2.6-dimethylpyrazine, pyridazine, pyrimidine, quinoxaline, 2.3 -Dimethylquinoxaline, quinazoline, phthalazine, phenazine, cinnoline, pteridine and the like. They can also be used as polymers such as polyvinylpyridine. The third of these
The grade amine may be added to the reactor separately from the raw materials and other catalyst components, or a portion of it may be previously treated with a portion of the other components of the catalyst system to convert it into a suitable compound such as a complex or adduct. It can also be used as -For example,
Although palladium chloride, ferrous chloride, and lysine can be added separately to a reactor and reacted, a palladium chloride-pyridine complex can be prepared in advance, and the complex, other raw materials, catalyst components, and tertiary amine can be reacted. It is also possible to additionally add and react.

The amount of tertiary amine used is at least 0.05 molar ratio, preferably at least 0.1 molar ratio, based on the nitro group of the nitro compound used as a raw material.

If the molar ratio is less than 0.05, the reaction becomes extremely slow and the selectivity decreases.

Although the process of the present invention can be carried out without the presence of a solvent, the use of a solvent is preferred in order to effectively carry out the invention.

Examples of solvents include aromatic solvents such as benzene, toluene, and xylene, nitriles such as acetonitrile and benzonitrile, sulfolane solvents such as sulfolane, and 1.1.2-trichloro-1゜2.2-trifluoro. Aliphatic halogenated hydrocarbons such as ethane, halogenated aromatic hydrocarbons such as monochlorobenzene, dichlorobenzene and trichlorobenzene, ketones, esters, tetrahydrofuran, 1,4-dioxane, 1.2-
Dimethoxyethane or the like can be used as a solvent.

The solvent is generally used in an amount of Ill or more, preferably in a weight ratio of 3 or more, relative to the aromatic nitro compound.

Even if the amount used is large, there is no problem with the reaction, and the upper limit of the amount used is determined mainly from an economic standpoint. If a solvent is not used, the reaction rate will be slow and the yield of the target product will be poor.

In carrying out the method of the present invention, there are no particular limitations on the method of charging, but it is desirable to add the nitro compound and the catalyst component after dissolving or partially dissolving them in the aromatic hydroxy compound or a suitable solvent.

The order of addition is also not limited, but can be varied within the constraints of the equipment used. For example, a suitable pressure reactor such as an autoclave is charged with a catalyst, an aromatic nitro compound, and an aromatic hydroxy compound, carbon monoxide is introduced under pressure, and the mixture is heated and stirred until the desired reaction is completed. Carbon monoxide can also be supplied intermittently or continuously by exhausting carbon dioxide gas generated as the reaction progresses. The reaction may be carried out batchwise, semi-continuously or continuously. Excess carbon monoxide after the reaction can be recycled.

The reaction temperature is generally maintained in the range of 100 to 250°C, with a range of 140 to 240°C being particularly preferred. Although the reaction proceeds faster at higher temperatures, a temperature of 160 to 220°C is usually sufficient.

The reaction pressure is 50 to 1000 kg as the partial pressure of carbon monoxide.
/-01 More preferably 100 to 500 kg/cdG
is within the range of

The reaction time varies depending on the nature of the nitro compound used, the reaction temperature, the reaction pressure, the type and amount of the catalyst, the reaction apparatus, etc., but is generally carried out in the range of 10 minutes to 10 hours. After the reaction is complete, the reaction mixture is cooled and evacuated, and the reaction product is processed by conventional methods including filtration, distillation, or other suitable separation methods to free the carbamide from unreacted materials, impurities, solvents, catalysts, etc. Separation of acid aryl esters is carried out.

〔Example〕

The present invention will be specifically explained using Examples or Comparative Examples.

In all of the following Examples and Comparative Examples, an electromagnetic stirring autoclave made of stainless steel (5OS-316L) was used for all reactions.

Further, the conversion rate and yield were calculated from the results of gas chromatography analysis and liquid chromatography analysis.

In addition, the corrosion rate was measured by inserting a test piece of 5O3-316L.
ll/ye calculated from its surface area and weight loss after reaction
Expressed in ar.

In addition, the following abbreviations of compounds were used. That is, dinitrotoluene is abbreviated as DNT,) lylene dicarbamate diphenyl ester is abbreviated as TDC-P, N-trotolyl) carbamic acid phenyl ester is abbreviated as TNC-P, and when it is necessary to indicate the position of a substituent, for example, 2 .2.4-DNT for 4-dinitrotoluene, l-rylene-2
, 2 for 4-dicarbamic acid diphenyl ester
．． A number indicating the position was added in front, such as 4-T D C-P.

Example-1 In an autoclave with an internal volume of 500 mA, 2.4-DN
T15.0g, phenol 31g dichlorobis(
pyridine) palladium 0.189 g, phosphoryl chloride 0.086 g 1 dichlorobis(pyridine) iron 0.321
g, quinoline 4.9g5o-dichlorobenzene 164
A solution consisting of g was charged. This solution was a homogeneous solution containing no insoluble matter. 160 kg/a after replacing the autoclave with carbon monoxide at 10 kg/cA twice
Pressurized to aG. Raise the temperature to 200℃ while stirring, and maintain the same temperature and reaction pressure of 250 to 200 kg/crA.
After reacting at G for 210 minutes, the reaction solution was cooled to 70° C., the pressure was released, and the reaction solution was analyzed by liquid chromatography. Reaction liquid is 70℃
It was a substantially homogeneous solution containing almost no insoluble matter.

As a result of the analysis, the reaction solution did not contain the raw material 2,4-DNT or the intermediate mononitro compound, and contained 23.9 g of 2,4-T.
Contains DC-P. The yield based on 2.4-DN'T was 80%. The corrosion rate of 5US-316L is 0
．． It was 07 Tsuru/year.

Comparative Examples-1 to 2 In order to clearly demonstrate the effect of the promoter system of the present invention, Comparative Example-1
Example-2 except that phosphoryl chloride was not used in Comparative Example-2, and dichlorobis(pyridine)iron was not used in Comparative Example-2, and the reaction was conducted for the reaction times shown in Table 1.
The reaction was carried out in the same manner as in 1. The results are shown in Table 1 again together with the results of Example-1. Any of the co-catalyst components of the present invention may be omitted (and the reaction rate may be reduced, resulting in the target T
The yield of DC-P decreased.

Comparative Example-3 To show the influence of the amount of phenol used in the present invention, 0-
The reaction was carried out in the same manner as in Example 1, except that 180 g of phenol was used without using dichlorobenzene. The results are shown in Table 2 together with the results of Example-1. Example-
The reaction results were significantly inferior to those of 1.

Example-2 Nitrobenzene 10.1 instead of 2,4-DNT
The reaction was carried out at 200° C. for 180 minutes in the same manner as in Example-1. The conversion rate of nitrobenzene was 100%, and phenylcarbamic acid phenyl ester was obtained with a yield of 90%.

Example-3 15.0 g of crude DNT obtained by dinitration of toluene
(2,4 combined 77%, 2.6 combined 19%, and 2
．． Contains about 4% of 3-13°4- and 2,5-units. ) was used to react in the same manner as in Example-1. The conversion rate of DNT is 1
The diester was obtained at a yield of 80% based on the 2,4- and 2.6 monomers in the raw materials, with no mononitro compound present. Corrosion rate of 5uS-316L is 0.09m/yea
It was r.

Comparative Example-4 2,4-D N 710.7g, phenol 200g,
The reaction was carried out in the same manner as in Example 1, except that 0.5 g of 5% palladium-carbon, 2.4 g of pyridine, and 0.13 g of ferric chloride were charged. The yield of 2.4-T D C-P was 1% or less, the yield of intermediate TNC was 40%, and unreacted 2.4-DNT was 20%.

Examples 4 to 10 2.4-D N T using various compounds as catalysts
Table 3 shows the results of the reaction between phenol and carbon monoxide. Conditions and methods other than those listed in Table 3 are the same as in Example-1.

Example 11 Nitrobenzene, phenol, and carbon monoxide were reacted in the same manner as in Example 2 except that isoquinoline or pyridine was used as the tertiary amine instead of quinoline.

N-phenylcarbamic acid phenyl ester was obtained in the same yield as in Example-2.

〔Effect of the invention〕

According to the method of the present invention, aromatic carbamic acid esters can be produced from aromatic nitro compounds, aromatic hydroxy compounds, and carbon monoxide in good yield and with good operability. Furthermore, the catalyst system according to the method of the present invention is extremely non-corrosive, allowing the use of commonly available inexpensive materials in the reactor.

Claims (1)

[Claims] 1) In a method for producing an aromatic carbamic acid aryl ester by reacting an aromatic nitro compound, an aromatic hydroxy compound and carbon monoxide in the presence of a catalyst, metallic palladium or a palladium compound or a halogenated phosphorus compound is used. A method for producing an aromatic carbamic acid aryl ester, which comprises reacting at high temperature and pressure using a catalyst system consisting of an iron compound and a tertiary amine.