JPS6125704B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing urethane, and more specifically, using a catalyst system consisting of a platinum group metal or a compound containing a platinum group element and an onium compound whose anion is a halogen, in the presence of an oxidizing agent, This invention relates to a method for producing urethane by reacting a primary amine or a secondary amine (excluding aromatic amines) with carbon monoxide and an organic hydroxyl compound. Urethanes are important compounds used in carbamate-based pesticides, etc., but conventionally, they have been made by reacting the corresponding isocyanates with alcohols, or by reacting them with alcohols.
It was produced by a method in which the corresponding amines and chloroformic acid esters were reacted. However, all of these methods have drawbacks, such as the need to use highly toxic and corrosive phosgene in order to produce isocyanates or chloroformates used as raw materials. On the other hand, a method has also been proposed in which primary amine, carbon monoxide, and alcohol are oxidatively converted into urethane using a noble metal catalyst without using phosgene. (Japanese Unexamined Patent Publication No. 120551/1983) However, in this method, the cocatalyst is a Lewis acid such as copper chloride, iron chloride, iron oxychloride, vanadium chloride, vanadium oxychloride, etc., and is capable of carrying out a redox reaction in the reaction system. Elemental chlorides must be dissolved in the reaction system, and these dissolved chlorides are highly corrosive to metal materials such as reaction vessels, piping, and valves, so expensive metal materials must be used. There is a problem with the equipment. Furthermore, in order to separate and recover these dissolved chlorides from the product urethanes, not only do they require complicated operations and a large amount of cost, but these cocatalysts also have the disadvantage of being difficult to use in redox reactions. Since the hydrogen chloride produced in the reduced state becomes the hydrochloride of unreacted amine, it cannot be completely returned to the original chloride even by reoxidation in the reaction system, and therefore it is not recovered. The drawback is that these cocatalysts also have to be re-prepared when the reaction is repeated, since some are sometimes partially reduced. In order to overcome these drawbacks, the present inventors have made the following points:
As a result of extensive research into methods for producing urethane by oxidatively converting primary or secondary amines (excluding aromatic amines) into urethanes, we found that Lewis acid and redox reactions are the main causes of these drawbacks. We have discovered a new catalyst system that allows the reaction to proceed catalytically without the use of chlorides of elements that carry out the reaction, and based on this knowledge, we have completed the present invention. That is, in the present invention, in producing urethane by reacting a primary amine or a secondary amine (excluding aromatic amines) with carbon monoxide and an organic hydroxyl compound in the presence of an oxidizing agent, (a) At least one selected from platinum group metals and compounds containing platinum group elements, and (b) selected from onium compounds whose anions are halogens and compounds that can produce these in a reaction system. The present invention provides a method for producing urethane characterized by using a catalyst system comprising at least one type. As described above, a major feature of the present invention is that at least one compound selected from platinum group metals and compounds containing platinum group elements, and at least one compound selected from onium compounds whose anion is a halogen. By using this catalyst system, urethane can be obtained with good selectivity and high yield from primary amines or secondary amines. This fact is truly surprising and has not been known until now, and could not have been expected from the prior art mentioned above (Japanese Unexamined Patent Publication No. 120551/1983). That is, in this prior art, a catalyst system in which a platinum group compound is used as a main catalyst and a chloride of an element that can undergo a redox reaction in a reaction system is used as a co-catalyst, such as palladium chloride as a typical example, is used. A catalyst system that combines iron oxychloride with iron oxychloride is used. In such a system, divalent palladium is involved in the reaction and is reduced to zero as the reaction progresses.
At the same time, trivalent iron is reduced to divalent iron, and this divalent iron is further oxidized. It is thought that the main product, urethane, is produced through a catalytic cycle of the so-called Watzker reaction type, in which iron is reoxidized by a chemical agent and returned to trivalent iron. As described above, in the prior art methods, it has been shown that the chloride of an element having a redox effect in the reaction system is essential as a reoxidizing agent for the main catalyst. Elements that have such a function are those that can undergo redox reactions selected from the elements of groups a to a and groups b to b of the periodic table, and specifically include copper and zinc. , mercury, thallium, tin, titanium, arsenic, antimony, bismuth, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, etc. Among them, only copper, vanadium, manganese, and iron have been tested. These examples are only described as examples, and these examples only involve urethanization reactions of aromatic primary amines, and do not exemplify reactions of aliphatic amines or alicyclic amines. In contrast, the method of the present invention uses onium compounds whose anions are halogens or compounds that can generate these in a reaction system, and these compounds do not contain any metal components or Under normal reaction conditions, the cation moiety cannot undergo a redox reaction. Therefore, it is presumed that the reaction of the present invention proceeds by a completely different reaction mechanism from the reactions described in the prior art. It is unclear how onium compounds whose anions are halogens act in the reaction of the present invention, but when combined with platinum group metals or compounds containing platinum group elements, primary It is clear that it plays an important role as a catalyst component in the oxidative urethanization reaction of amines or secondary amines. In other words, the urethanization reaction of this reaction will not proceed quickly if only an onium compound whose anion is a halogen is used, and even if only a platinum group metal or a compound containing a platinum group element is used, under the conditions of this reaction, urethane formation will not proceed quickly. The chemical reaction hardly progresses, or even if it does proceed, only a small amount of urethane is obtained, and especially when only platinum group elements in a metallic state are used, hardly any urethane is obtained. For example, palladium is one of the effective catalyst components for this reaction, but the reaction hardly progresses if only palladium black, which is zero-valent metal palladium, is used alone. However, when an onium compound whose anion is a halogen, such as tetramethylammonium iodide, is added, urethane can be obtained almost quantitatively. In this way, in the method of the present invention, a solid platinum group compound in a metallic state can also be used as one of the catalyst components, which means that the expensive platinum group compound can be separated from the reaction system by a simple method such as filtration. , it has been shown that it can be recovered, which is industrially advantageous. Another major feature of the present invention is that it uses onium compounds whose anions are halogens, and since most of these compounds are water-soluble, they can be easily separated and recovered from the product. Unlike conventionally used heavy metal chlorides, they do not mix into products as contaminants. The platinum group metal and platinum group element-containing compound used in the method of the present invention may contain at least one component selected from platinum group elements such as palladium, rhodium, platinum, ruthenium, iridium, and osmium. There are no particular limitations on these elements, and these elements may be in a metallic state or may be components forming a compound. In addition, these catalyst components include activated carbon, graphite,
Silica, alumina, silica - alumina, silica -
It may be supported on a carrier such as titania, titania, zirconia, barium sulfate, calcium carbonate, asbestos, bentonite, diatomaceous earth, polymer, ion exchange resin, zeolite, molecular sieve, magnesium silicate, magnesia, etc. . Examples of platinum group elements in the metallic state include metals such as palladium, rhodium, platinum, ruthenium, iridium, and osmium, these metal blacks, and catalyst components containing these metal ions on the above-mentioned carrier, and then hydrogen and Those reduced with formaldehyde, alloys or intermetallic compounds containing these metals, etc. are used. Further, the alloy or intermetallic compound may be one of these platinum group metals, or may be one of these platinum group metals, or may contain other elements such as selenium, tellurium, sulfur, antimony, bismuth,
Copper, silver, gold, zinc, tin, vanadium, iron, cobalt, nickel, mercury, lead, thallium, chromium,
It may also contain molybdenum, tungsten, or the like. On the other hand, compounds containing platinum group elements include, for example, inorganic salts such as halides, sulfates, nitrates, phosphates, and borates; organic acid salts such as acetates, oxalates, and formates; and cyanides. ; Hydroxides; Oxides; Sulfides; Nitro group, cyano group,
Complex compounds of metals such as metal salts containing anions such as halogens and oxalate ions, and salts or complexes containing ammonia, amines, phosphines, carbon monoxide, chelate ligands, etc.; organic ligands or organic groups Examples include organometallic compounds having the following. Among these catalyst components, those containing palladium or rhodium or both are particularly preferred, such as Pd black; Pd black;
-C, Pd-Al ₂ O ₃ , Pd-SiO ₂ , Pd-TiO ₂ , Pd-
Supported palladium catalysts such as ZrO ₂ , Pd-BaSO ₄ , Pd-CaCO ₃ , Pd-asbestos, Pd-zeolite, Pd-molecular sieve; Pd-Pb, Pd-
Se, Pd-Te, Pd-Hg, Pd-Tl, Pd-P, Pd-
Cu, Pd―Ag, Pd―Fe, Pd―Co, Pd―Ni, Pd―
Alloys or intermetallic compounds such as Rh; and these alloys or intermetallic compounds supported on the above-mentioned supports; PdCl ₂ , PdBr ₂ , PdI ₂ , Pd
(NO ₃ ) ₂ , PdSO ₄ and other inorganic salts; Pd
(OCOCH ₃ ) ₂ , organic acid salts such as palladium oxalate; Pd(CN) ₂ ; PdO; PdS; M ₂ [PdX ₄ ], M ₂
Palladate salts represented by [PdX ₆ ] (M represents an alkali metal or ammonium ion,
represents a nitro group, a cyano group, or a halogen. ); Ammine complexes _of palladium such as [Pd(NH ₃ ) _{4 ]} X ₂ , [Pd(en) ₂ ] ) ₂ , PdCl ₂ (PR ₃ ) ₂ , Pd
(CO)( _PR3 ) ₃ , Pd( _PPh3 ) ₄ , PdCl(R)
(PPh ₃ ) ₂ , Pd(C ₂ H ₄ )(PPh ₃ ) ₂ , Pd(C ₃ H ₅ ) ₂ and other complex compounds or organometallic compounds (R represents an organic group); Pd(acac) ₂ Complex compounds coordinated with chelate ligands such as Ph black; supported rhodium catalysts similar to Pd; Rh alloys or intermetallic compounds similar to Pd, and those supported on supports; RhCl ₃
and hydrates, RhBr ₃ and hydrates, RhI ₃ and hydrates, Rh ₂ (SO ₄ ) ₃ and inorganic salts such as hydrates; Rh ₂
(OCOCH ₃ ) ₄ ; Rh ₂ O ₃ , RhO ₂ ; M ₃ [RhX ₆ ] and hydrates (M and X have the same meanings as above); [Rh
Rhodium ammine complexes such as ( _NH3 ) ₅ ] _X3 , [Rh(en) ₃ ] _X3 ; Rhodium carbonyl clusters such as _Rh4 (CO) ₁₂ , _Rh6 (CO) ₁₆ ;
(CO) ₂ ] ₂ , RhCl ₃ (PR ₃ ) ₃ , RhCl (PPh ₃ ) ₃ , RhX
Complex compounds or organometallic compounds such as (CO)L ₂ (X has the same meaning as above, and L is a ligand consisting of an organophosphorus compound and an organoarsenic compound), RhH(CO)(PPh ₃ ) ₃ There are many types. In the present invention, only one type of these platinum group metals or compounds containing platinum group elements may be used, or two or more types may be used as a mixture, and there is no particular restriction on the amount used. Usually, it is desirable that the amount of the component containing the platinum group element is in the range of 0.0001 to 50 mol % based on the amine. Furthermore, the onium compound used in the present invention, in which the anion is a halogen, is a compound containing an element with a lone pair of electrons, and a proton or other cationic reagent is bonded to these lone pairs to generate a lone electron. An element having a pair increases the valence of a covalent bond by 1 to become a cation, and has a halogen anion as a counter ion. Examples of such onium compounds include ammonium compounds, phosphonium compounds ([R ¹ R ² R ³ R ⁴ P] X), arsonium compounds ( ^[ R ¹ R ² R ³ R ⁴ As] R ² R ^{3 R 4} Sb]X), oxonium compounds ([ ^{R 1 R 2 R 3 O ] R 3} S] (O)X) ^, selenonium compounds, ([ ^{R 1 R 2 R 3 Se ] 3} Sn]X) ^, iodonium compounds ( ^[ R ¹ R ^{2 I ]} Represents a group selected from group groups and aromatic aliphatic groups, each of which may be the same or, in some cases, may be a constituent element of a ring containing an element having a lone pair of electrons. X represents a halogen selected from F, Cl, Br, and I as described above.Such halogenated onium compounds include ammonia, amines, phosphine compounds, arsine compounds, It is easily obtained by reaction with stibine compounds, oxy compounds, sulfide compounds, sulfoxide compounds, selenide compounds, telluride compounds, etc. These compounds may be produced outside the reaction system, or These may be produced within the system. Of course, they may be produced by other methods, or may be produced within the reaction system by other methods. Preferred are halogenated ammonium compounds, halogenated phosphonium compounds, halogenated arsonium compounds and halogenated sulfonium compounds, and particularly preferred are halogenated ammonium compounds and halogenated phosphonium compounds. formula() Hydrogen halide salts and quaternary ammonium halides of nitrogen-containing compounds having the group represented by Here, three or four lines connected to N represent bonds between the nitrogen atom and other atoms or groups, and X represents F, Cl, Br, and I as described above. In formula (), examples of atoms or groups bonded to nitrogen include hydrogen, alkali metal atoms, hydroxyl groups, aliphatic groups, alicyclic groups, aromatic groups, araliphatic groups, and heterocyclic groups. Further, in formula (), nitrogen itself may be an element constituting a ring, as in, for example, piperidine, pyridine, or quinoline. Furthermore, two or more groups represented by formula () may be present in the molecule. Such ammonium halide compounds are
It can be easily obtained by a reaction between a corresponding nitrogen-containing compound and a hydrogen halide, or a reaction between a nitrogen-containing compound and an alkyl halide or an aryl halide. Examples of nitrogen-containing compounds that can form salts or quaternary ammonium halides with hydrogen halides, alkyl halides, or aryl halides include ammonia; primary amines, secondary amines, and tertiary amines. hydroxylamines; hydrazines; hydrazones; amino acids; oximes; imidoesters; amides and various nitrogen-containing heterocyclic compounds. Preferred hydrogen halide salts of nitrogen-containing compounds include ammonia salts such as ammonium chloride, ammonium bromide, and ammonium iodide; salts of primary amines or secondary amines used as raw materials of the present invention; diphenylamine, triphenylamine; Salts of aromatic amines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, dimethylamine, trimethylamine, diethylamine, triethylamine, dipropylamine, tripropylamine, dibutylamine, tripropylamine, methylethylamine , salts of aliphatic amines such as dimethylethylamine, diethylmethylamine, ethylbutylamine, dibutylmethylamine, tributylamine, trihexylamine, ethylenediamine, hexamethylenediamine; fatty acids such as cyclopropylamine, cyclohexylamine, N-methylcyclohexylamine, etc. Salts of cyclic amines; benzylamine, N-methylbenzylamine, N,N
-Salts of aromatic aliphatic amines such as diethylbenzylamine, dibenzylamine; Salts of nitrogen heterocyclic compounds; dimethylacetamide, N
- Amide salts such as methylpyrrolidone are used. Examples of quaternary ammonium halides include tetramethylammonium halide, tetraethylammonium halide, tetrapropylammonium halide, tetrabutylammonium halide, trimethylethylammonium halide, trimethylbutylammonium halide, diethyl dibruammonium halide. Aliphatic quaternary ammonium halides such as halogenated N,N,N-trimethylcyclohexyl ammonium; alicyclic quaternary ammonium halides such as halogenated N,N,N-trimethylcyclohexylammonium; aromatic aliphatic such as halogenated tetrabenzylammonium, halogenated trimethylbenzylammonium, etc. Quaternary ammonium halides; aromatic quaternary ammonium halides such as halogenated N,N,N-trimethylphenylammonium, halogenated N,N,N-triethylphenylammonium; halogenated N-methylpyridinium, Halogenated N-ethylpyridinium, Halogenated N
- Heterocyclic quaternary ammonium halides such as methylquinolinium, halogenated N-ethylquinolinium, halogenated N,N-dimethylpiperidinium, and halogenated N,N'-dimethylimidazolinium are preferred. used. Examples of halogenated phosphonium compounds include symmetrical tetraalkylphosphonium compounds such as halogenated tetramethylphosphonium, halogenated tetraethylphosphonium, halogenated tetrapropylphosphonium, halogenated tetrabutylphosphonium, and halogenated tetrahexylphosphonium; halogenated ethyltrimethyl Phosphonium, asymmetric tetraalkylphosphonium compounds such as halogenated diethyldimethylphosphonium; halogenated tetraphenylphosphonium,
Symmetrical tetraarylphosphonium compounds such as halogenated tetra(p-tolyl)phosphonium;
Asymmetric tetraarylphosphonium compounds such as halogenated (α-naphthyl)triphenylphosphonium; alkylaryl mixed phosphonium compounds such as halogenated methyltriphenylphosphonium, halogenated ethyltriphenylphosphonium, and halogenated phenyltrimethylphosphonium; halogen Tetraaralkylphosphonium compounds such as tetrabenzylphosphonium oxide are preferably used. Examples of halogenated arsonium compounds include symmetrical tetraalkylarsonium compounds such as tetramethylarsonium halide and tetraethylarsonium halide; asymmetrical tetraalkylarsonium compounds such as methyltriethylarsonium halide and dimethyldiethylarsonium halide; Symmetrical tetraarylarsonium compounds such as halogenated tetraphenylarsonium; alkylaryl mixtures such as halogenated methyltriphenylarsonium, halogenated ethyltriphenylarsonium, and halogenated phenyltrimethylarsonium Arsonium compounds and the like are preferably used. Examples of halogenated sulfonium compounds include symmetrical or asymmetrical alkylsulfonium compounds such as trimethylsulfonium halide, triethylsulfonium halide, and methyldiethylsulfonium halide; arylsulfonium compounds such as triphenylsulfonium halide; dimethyl halide Alkylarylsulfonium compounds such as phenylsulfonium and halogenated methyldiphenylsulfonium; halogenated bicyclo(2,2,1')-heptane-1
- Cyclic sulfonium compounds such as sulfonium and thiopyrylium halide are preferably used. These halogenated onium compounds can be used alone or in combination of two or more. Of course, one molecule may contain two or more of the same or different onium halide groups. Further, among such halogenated onium compounds, those in which the halogen species is bromine or iodine are preferably used, and those containing iodine are particularly preferred. The amount of the onium halide compound used in the present invention is not particularly limited, but is usually in the range of 0.001 to 10,000 times the amount of the metal element in the platinum group element-containing component used. It is preferably used in Primary amine or secondary amine used as raw material of the present invention
A class amine (excluding aromatic amines) is a compound containing at least one amino group in one molecule as shown by the following formula: NH. Here, the two lines connected to N represent bonds between the nitrogen atom and other atoms or groups. Examples of such atoms or groups include hydrogen, halogen, alkali metal atoms, hydroxyl groups, amino groups, aliphatic groups, alicyclic groups, araliphatic groups, and heterocyclic groups. Further, this nitrogen may itself be an element constituting a ring, such as in pyrrole, piperidine, piperazine, morpholine, and the like. Examples of such primary amines include ammonia, methylamine, ethylamine, propylamine (each isomer), butylamine (each isomer), pentylamine (each isomer), hexylamine (each isomer), and dodecylamine. Aliphatic primary monoamines such as (each isomer); ethylenediamine, diaminopropane (each isomer), diaminobutane (each isomer), diaminopentane (each isomer), diaminohexane (each isomer), diaminodecane Aliphatic primary diamines such as (each isomer); 1,2,3-triaminopropane, triaminohexane (each isomer), triaminononane (each isomer), triaminododecane (each isomer) alicyclic primary triamines such as cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, diaminocyclobutane, diaminocyclohexane (each isomer), triaminocyclohexane (each isomer); Polyamines; benzylamine, di(aminomethyl)benzene (each isomer), aminomethylpyridine (each isomer), di(aminomethyl)pyridine (each isomer),
Aroaliphatic primary mono- and polyamines such as aminomethylnaphthalene (each isomer), di(aminomethyl)naphthalene (each isomer); aminofuran (each isomer), aminotetrahydrofuran (each isomer), aminothio Heterocyclic primary amines such as phene (all isomers), aminopyrrole (all isomers), and aminopyrrolidine (all isomers) are preferably used. Examples of secondary amines include aliphatic secondary amines such as dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, ethylmethylamine, ethylpropylamine, butylmethylamine, and ethylhexylamine; Alicyclic secondary amines such as cyclopropylamine, dicyclohexylamine, methylcyclohexylamine; aromatic aliphatic secondary amines such as dibenzylamine, ethylbenzylamine, diphenethylamine; difuranylamine, dithiophenylamine, etc. Heterocyclic secondary amines; pyrrolidine, pyrrole, 3-pyrrolidone, indole, carbazole, piperidine, piperazine, β-piperidone, γ-piperidone, imidazole, pyrazole, triazole, benzimidazole, morpholine, 1,3-oxazine, etc. Cyclic secondary amines and the like are preferably used. In addition, in these primary amines and secondary amines, one or more hydrogens of the organic group bonded to nitrogen may be substituted with other substituents, such as lower aliphatic groups, amino groups, carboxyl groups, ester groups, alkoxy groups, cyano groups, Halogen, nitro group, urethane group, sulfoxide group, fluorone group, carbonyl group, amide group,
It may be substituted with an aromatic group, an aromatic aliphatic group, or the like. Furthermore, these primary amines and secondary amines may have unsaturated bonds. Further, it may be a hydrazine type compound in which the above-mentioned amino group is directly bonded to an organic group having a nitrogen atom through N—N. Compounds having an amino group and a hydroxyl group in the molecule, such as ethanolamine and propanolamine, can also be used in this reaction, and in such cases, a cyclic urethane can be produced. One or more of these primary amines and secondary amines may be used. The organic hydroxyl compound used in the present invention is a monohydric or polyhydric alcohol, or a monohydric or polyhydric phenol, and examples of such alcohol include linear or branched alcohols having 1 to 20 carbon atoms. monohydric or polyhydric alkanols or alkenols in the chain,
Examples include monovalent or polyvalent cycloalkanols, cycloalkenols, and aralkyl alcohols. Furthermore, these alcohols may contain other inert substituents, such as halogen atoms, cyano groups, alkoxy groups, sulfoxide groups, sulfone groups, carbonyl groups, ester groups, and amide groups. Specific examples of such alcohols include methanol, ethanol, propanol (each isomer), butanol (each isomer), pentanol (each isomer), hexanol (each isomer), heptanol (each isomer), Octanol (each isomer), Nonyl alcohol (each isomer), Decyl alcohol (each isomer), Undecyl alcohol (each isomer), Lauryl alcohol (each isomer), Tridecyl alcohol (each isomer), Tetra Aliphatic alcohols such as decyl alcohol (each isomer) and pentadecyl alcohol (each isomer); cycloalkanols such as cyclohexanol and cycloheptanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Alkylene glycol monoethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol, propylene glycol, diethylene glycol, Polyhydric alcohols such as propylene glycol, glycerin, hexanetriol, and trimethylolpropane; aralkyl alcohols such as benzyl alcohol are used. Examples of phenols that can be used include phenol, various alkylphenols, various alkoxyphenols, various halogenated phenols, dihydroxybenzene, 4,4'-dihydroxy-diphenylmethane, bisphenol-A, and hydroxynaphthalene. The oxidizing agent used in the present invention may be any conventional oxidizing agent, but preferred are molecular oxygen, organic nitro compounds, or mixtures thereof. Particularly preferred is molecular oxygen. This molecular oxygen is pure oxygen or a substance containing oxygen, which may be air, or other gases that do not inhibit the reaction of air or pure oxygen, such as nitrogen,
It may be diluted by adding an inert gas such as argon, helium, or carbon dioxide. In some cases, it may also contain gases such as hydrogen, carbon monoxide, hydrocarbons, and halogenated hydrocarbons. Further, the organic nitro compound may be any of alicyclic, aliphatic, and aromatic nitro compounds. Examples of alicyclic nitro compounds include nitrocyclobutane, nitrocyclopentane, nitrocyclohexane, dinitrocyclohexane (each isomer), bis-(nitrocyclohexyl)-methane, and examples of aliphatic nitro compounds include nitromethane, nitroethane, Nitropropane (each isomer), Nitrobutane (each isomer), Nitropentane (each isomer)), Nitrohexane (each isomer), Nitrodecane (each isomer), 1,2-dinitroethane, Dinitropropane (each isomer), dinitrobutane (each isomer), dinitropentane (each isomer), dinitrohexane (each isomer), dinitrodecane (each isomer), phenylnitromethane,
Bis-(nitromethyl)-cyclohexane, bis-(nitromethyl)-benzene, etc.; examples of aromatic nitro compounds include nitrobenzene, dinitrobenzene (each isomer), nitrotoluene (each isomer), dinitrotoluene (each isomer) , nitropyridine (each isomer), dinitropyridine (each isomer), nitronaphthalene (each isomer), dinitronaphthalene (each isomer), and the like. In addition, in these nitro compounds, at least one hydrogen has another substituent, such as a halogen atom, an amino group, a cyano group, an alkyl group, an alicyclic group, an aromatic group, an aralkyl group, an alkoxy group, a sulfoxide group, It may be substituted with a sulfone group, carbonyl group, ester group, amide group, etc. In the present invention, when the oxidizing agent is molecular oxygen,
For example, the reaction of primary amines proceeds according to the following general reaction formula. R ⁵ (NH ₂ ) _o +0.5n・O ₂ +n・CO+n・R ⁶ OH →R ⁵ (NHCOOR ⁶ )n+n・H ₂ O (here, R ⁵ is the organic residue of the primary amine, and R ⁶ is The organic residue of the organic hydroxyl compound (n represents the number of primary amino groups in one molecule of the amino compound) Molecular oxygen may be less or more than the equivalent amount, but oxygen / carbon monoxide or oxygen /Organic hydroxyl compound mixtures should be used outside the explosive field. In addition, when an organic nitro compound is used as an oxidizing agent, the organic nitro compound itself also participates in the reaction and becomes urethane, so if the structure is different from the amino compound, a urethane compound corresponding to each structure will be obtained, and the structure of both will be different. It goes without saying that the same urethane compound can be obtained if they are the same. In this case, the urethanization reaction, for example, the reaction of a primary amine, proceeds according to the following reaction formula. 2R ⁵ (NH ₂ ) _n +R ⁷ (NO ₂ ) _n +3m・CO+3m・R ⁶ OH →2R ⁵ (NHCOOR ⁶ ) _n +R ⁷ (NHCOOR ⁶ ) _n +2m・H ₂ O (Here, R ⁵ and R ⁶ are has the same meaning as above,
( ^R7 represents the organic residue of the organic nitro compound, m represents the number of amino groups and nitro groups in the amino compound and the nitro compound) When only the organic nitro compound is used as an oxidizing agent, the amount of the amino compound and the organic nitro compound The ratio is
Although it is preferable to use 1 mole of nitro group per 2 moles of amino group, it is of course possible to carry out the reaction at a value deviating from this stoichiometric ratio. Generally, the equivalent ratio of amino group to nitro group is 1.1:1
4:1 to 4:1, preferably 1.5:1 to 2.5:1
It will be carried out in Of course, if molecular oxygen or other oxidizing agents are used at the same time, the amount of organic nitro compound may be less than the stoichiometric amount. In the method of the present invention, it is preferable to use an excess of the organic hydroxyl compound as the reaction solvent, but if necessary, a solvent that does not adversely affect the reaction can also be used. Examples of such solvents include aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; halogenated aromatics such as chlorobenzene, dichlorobenzene, trichlorobenzene, fluorobenzene, chlorotoluene, chlornaphthalene, and bromnaphthalene. Hydrocarbons; halogenated aliphatic hydrocarbons or halogenated alicyclic hydrocarbons such as chlorhexane, chlorocyclohexane, trichlorotrifluoroethane, methylene chloride, and carbon tetrachloride; nitriles such as acetonitrile and benzonitrile; sulfolane, Sulfones such as methylsulfolane and dimethylsulfolane; tetrahydrofuran, 1,
Ethers such as 4-dioxane and 1,2-dimethoxyethane; Ketones such as acetone and methyl ethyl ketone; Esters such as ethyl acetate and ethyl benzoate; N,N-dimethylformamide,
Examples include amides such as N,N-dimethylacetamide, N-methylpyrrolidone, and hexamethylphosphoramide. In the method of the present invention,
Other additives can also be added to the reaction system as necessary to carry out the reaction more efficiently. Suitable examples of such additives include zeolites, tertiary amines, and alkali metal salts and alkaline earth metal salts of acids such as hydrohalic acid, boric acid, aluminic acid, carbonic acid, silicic acid, and organic acids. It is. In the method of the present invention, the reaction is usually carried out at 80 to 300°C.
Preferably it is carried out at a temperature range of 120 to 220°C. The reaction pressure is 5 to 500Kg/cm ² , preferably 20 to 300Kg/cm 2 .
Kg/ ^cm2 , and the reaction time varies depending on the reaction system, catalyst system, and other reaction conditions, but is usually from several minutes to several hours. Furthermore, the reaction of the present invention can be carried out either batchwise or continuously, in which the reaction solution is continuously extracted while continuously supplying the reaction components. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Example 1 In a stirring autoclave with an internal volume of 140 ml, 40 m mol of cyclohexylamine, 40 ml of ethanol,
After adding 0.5 mg atom of palladium black and 2 mmol of tetramethylammonium iodide and replacing the inside of the system with carbon monoxide, 80 kg/cm ² of carbon monoxide and then 6 kg/cm ² of oxygen were introduced under pressure. 1 at 160℃ while stirring
After reacting for an hour, the reaction mixture was filtered to obtain a pale yellow solution. As a result of analyzing this solution, the reaction rate of cyclohexylamine was 82%, the yield of ethyl N-cyclohexylcarbamate was 80%, and the selectivity was 98%.
It was %. When ethanol was distilled off from this solution under reduced pressure, pale yellow crystals were precipitated. This crude crystal is ethyl N-cyclohexylcarbamate with a purity of 98%.
White crystals with 100% purity were obtained by recrystallizing once from ethanol. Examples 2 to 16 Table 1 shows the results of the same reaction as in Example 1, except that 2 mmol of various onium halide compounds were used in place of tetramethylammonium iodide.

【table】

[Table] Comparative Example 1 The same reaction as in Example 1 was carried out using only palladium black without using any onium halide compound. As a result, the reaction rate of cyclohexylamine was 10
%, ethyl N-cyclohexylcarbamate was produced in a yield of only 3%. Example 17 β in a stirring autoclave with an internal volume of 200 ml.
-Phenethylamine 50m mol, ethanol 50ml,
1g of Rh/C with 5w% rhodium supported on activated carbon,
After adding 3 mmol of tetramethylammonium iodide and replacing the inside of the system with carbon monoxide, 80 kg/cm ² of carbon monoxide and then 6 kg/cm ² of oxygen were introduced under pressure. After reacting at 160°C for 1 hour with stirring, the reaction mixture was filtered and the filtrate was analyzed. As a result, the reaction rate of β-phenethylamine was 80%, and the yield of ethyl N-(β-phenethyl)carbamate was 72%. The selection rate is
It was 90%. Comparative Example 2 The same reaction as in Example 17 was carried out without using tetramethylammonium iodide, but the reaction rate of β-phenethylamine was 9% and the yield of ethyl N-(β-phenethyl)carbamate was 2%. It was below. Example 18 The same reaction as in Example 17 was carried out except that 0.5 mmol of ruthenium black was used instead of Rh/C. As a result, β
-The reaction rate of phenethylamine is 55%, and N-(β
The yield of ethyl carbamate (phenethyl) is 45%.
The selection rate was 82%. Comparative Example 3 The same reaction as in Example 18 was carried out without using tetramethylammonium iodide, but the reaction rate of β-phenethylamine was 8% and the yield of ethyl N-(β-phenethyl)carbamate was 2%. It was below. Example 19 In a stirring autoclave with an internal volume of 200 ml.
-Octylamine 30m mol Nitrobenzene 15m
mol, methanol 50ml, palladium chloride 0.5m mol
Add 3mmol of tetrabutylammonium iodide and replace the system with carbon monoxide.
140Kg/cm ² was press-fitted. 5 at 180℃ while stirring
Allowed time to react. As a result of analyzing the reaction solution, the reaction rates of n-octylamine and nitrobenzene were 35% and 42%, respectively, and 7 mmol and 3 mmol of methyl N-n-octylcarbamate and methyl N-phenylcarbamate were produced, respectively. was. Examples 20 to 26 Table 2 shows the results of similar reactions in Example 1 using various platinum group metals or compounds containing platinum group elements in place of paldium black.

[Table] In these Examples, 0.5 mg atom of the platinum group metal or platinum group compound was used as the metal element, and the % expression indicates the weight % of the supported catalyst component. Pd-Te/C is obtained by co-supporting palladium chloride and tellurium dioxide at a molar ratio of 10:3 on activated carbon, which is then reduced with hydrogen at 350°C. Example 27 Example 1 was prepared by using 40 mol of di-n-butylamine in place of cyclohexylamine in Example 1 and 2 m mol of methyltriphenylphosphonium iodide in place of tetramethylammonium iodide.
As a result of carrying out exactly the same reaction as above, the reaction rate of di-n-butylamine was 85%, the yield of ethyl N,N-di-n-butylcarbamate was 78%, and the selectivity was 92%.
It was %. Example 28 The reaction was carried out in exactly the same manner as in Example 1 except that 40 mmol of piperidine was used instead of cyclohexylamine in Example 1. As a result, the reaction rate of piperidine was 83% and the yield of N-ethoxycarbonylpiperidine was The selection rate was 94% with 78%. Example 29 The reaction was carried out in exactly the same manner as in Example 1 except that 15 mmol of 1,6-hexamethylenediamine was used instead of cyclohexylamine in Example 1. As a result, the reaction rate of 1,6-hexamethylenediamine was
The yield of diethyl 1,6-hexamethylenedicarbamate was 87% and the selectivity was 93%. Example 30 Cyclohexylamine 40m mol, ethanol 20
ml, palladium black 0.5mg atom and hydrogen iodide 3m
mol of ethanol solution was placed in an autoclave and the reaction was carried out in the same manner as in Example 1. As a result, the reaction rate of cyclohexylamine was 80%, the yield of ethyl N-cyclohexylcarbamate was 70%, and the selectivity was 88%. It was hot. Example 31 The reaction was carried out in exactly the same manner as in Example 1 except that 20 mmol of piperazine was used instead of cyclohexylamine in Example 1. As a result, the reaction rate of piperazine was 88%, and N,N'-diethoxycarbonyl The yield of piperazine was 83% and the selectivity was 94%.

Claims (6)

[Claims] 1. A method for producing urethane by reacting a primary amine or a secondary amine (excluding aromatic amines) with carbon monoxide and an organic hydroxyl compound in the presence of an oxidizing agent, comprising: (a) a platinum group metal and a platinum group metal; (b) At least one type selected from compounds containing the element and (b) at least one type selected from onium compounds whose anions are halogens and compounds that can generate these in a reaction system. A method for producing urethane, characterized by using a catalyst system consisting of: 2. 2. The method of claim 1, wherein the oxidizing agent is molecular oxygen or an organic nitro compound or both. 3. 3. The method of claim 2, wherein the oxidizing agent is molecular oxygen. 4. 4. The method according to claim 1, wherein the platinum group metal and the compound containing the platinum group element are palladium, rhodium, palladium compounds, and rhodium compounds. 5. The method according to any one of claims 1 to 4, wherein the onium compound is an ammonium compound, a phosphonium compound, an arsonium compound, or a sulfonium compound. 6. 6. The method according to any one of claims 1 to 5, wherein the halogen species is iodine.