DE19635723A1 - Catalyst composition giving high conversion and selectivity - Google Patents

Abstract

A composition containing: (a) a sub-group VIII metal or compound, (b) an organic heterocyclic nitrogen compound, (c) a metallocene of formula (I) and/or (d) a half-sandwich complex of formula (II) is claimed; in which M, M' = iron (Fe), cobalt, nickel, ruthenium, chromium, manganese, vanadium, titanium, zirconium or hafnium or M' = molybdenum or tungsten. R1-R5 = (1) hydrogen (H); (2) 1-24 carbon (C) alkyl, aryl or aralkyl; (3) a condensed aliphatic, aromatic or heterocyclic ring system with \} 40 C, optionally with aliphatic or aromatic substituents; (4) a group of the formula -(X)n-Y(R6)R7; X = CR8R9 or SiR8R9; R8, R9 = H or 1-26 C alkyl; n = 0-3; Y = nitrogen (N), phosphorus, arsenic or antimony; R6, R7 = H or alkyl, aryl or aralkyl with > 40 C or together = part of an aliphatic or aromatic ring system; or (5) one of R1-R5 with one of R'1-R'5 = a divalent group of the formula -A(R10)(R11)-a; A = C or silicon (Si); R10, R11 = H or 1-24 C alkyl; a = 1-6; x = 2-4; y = 1 or 2. Also claimed is a method of preparing isocyanates by reacting organic nitro- and/or nitroso-compounds with carbon monoxide (CO) in the presence of (I).

Description

The present invention relates to a composition and its composition Use for the one-step production of isocyanates from organic Nitro and / or nitroso compounds as well as a single-stage process Production of isocyanates, which is the combination according to the invention served setting.

Organic isocyanates are valuable and versatile materials, for example way for the production of polyurethanes or herbicides. Particularly important Examples of isocyanates are tolylene diisocyanate (TDI) and methylene-4,4'-di phenyl diisocyanate (MDI). There have been a variety of in recent years Try alternatives to the common representation of isocyanates or their To find precursors, the urethanes. The usual procedure is based on the "phosgene route" (see, for example, "Recent Advances in Isocyanate Chemistry", S. Ozaki, Chem. Rev. 1972, 72, 457-496). The problem here are high sales of chlorine via phosgene and carbamic acid chloride in chlorine hydrogen, the toxicity of the phosgene and the associated high Safety requirements, the corrosiveness of the reaction mixture and the toxicity of the solvents usually used. Other manufacturing processes for isocyanates are therefore becoming increasingly important.  

One variant is the reductive carbonylation of nitro and / or nitroso compounds with carbon monoxide and a transition metal catalyst. This method has two advantages: first, the use of high toxic phosgene avoided, on the other hand, the hydrogenation step the conventional route (implementation of the nitro compound to correspond the amine derivative) can be dispensed with. The isocyanate is therefore in one get one-step reaction directly.

The principle of this isocyanate production has long been known. As Kataly In the reductive carbonylation, catalysts become Group VIII metals used.

DE-OS 12 37 103 includes the use of Edelme tallen like palladium, either on a support or as a salt, as in for example PdCl₂, known.

DE-OS 12 83 230 also relates to a method, accordingly a catalytic converter gate is used on the basis of a noble metal. Particularly good Stige results are in combination with other catalysts such. B. Lewis acids achieved. Examples of these are halides of iron, aluminum um, tin, titanium, gallium or copper.

In DE-PS 16 68 529 the use of mixed catalysts is be wrote the at least one palladium or rhodium halide and at least one oxide of the transition metals vanadium, molybdenum, tungsten, Contain niobium, chrome or tantalum.

A catalyst system made from a precious metal halide, an aromatic, nitrogen-containing heterocyclic compound and transition metal oxides is described by DE-OS 18 15 517.  

DE-OS 19 44 747 also relates to a process for the production of organic isocyanates, the catalyst system used ver ver contains divided iron oxide.

DE-OS 21 65 355 describes a one-step process for the preparation aromatic isocyanates from the corresponding nitro compounds and Carbon monoxide in the presence of palladium and / or rhodium halides, heteroaromatic nitrogen compounds and an iron and / or manganese molybdate.

Finally, a catalyst system is used in DD-PS 1 23 807, that of at least one halide of the transition metals of VIII group, at least one organic nitrogen compound and one Cocatalyst, which contains at least one iron-vanadium mixed oxide.

In the reactions described, the cocatalyst is in the form of Transition metal oxides or halides used in organic Solvents are sparingly soluble and only under reaction conditions become soluble or change to a soluble form. This results in the Rule for difficulties with a possibly necessary follow-up dose tion of the cocatalyst. It was therefore the task of a team to find setting, which on the one hand guarantees a high reaction turnover and on the other hand is very soluble in organic solvents in order to to avoid difficulties mentioned in the subsequent dosing.

Surprisingly, it has now been found that a composition at least containing a metal or a compound of a metal VIII. Group of the Periodic Table, an organic, heterocyclic, stick substance-containing compound and an optionally substituted or given  bridged metallocene according to the above disadvantages of the catalysts does not have the prior art.

The invention therefore relates to at least one composition containing

• a) a metal or a compound of a metal of subgroup VIII of the periodic table,
• b) an organic, heterocyclic, nitrogen-containing compound,
• c) a compound of formula I. where M is Fe, Co, Ni, Ru, Cr, Mn, V, Ti, Zr or Hf and the radicals R¹ to R⁵ and R′¹ to R′⁵ each independently
  • c1) hydrogen,
  • c2) an alkyl, aryl or aralkyl radical having 1 to 24 carbon atoms
  • c3) a fused-on aliphatic or aromatic or heterocyclic ring system with up to 40 C atoms, which in turn can each be aliphatic or aromatic substituted,
  • c4) a substituent of the formula II where each X is CR⁸R⁹ or SiR⁸R⁹, where R⁸ and R⁹ are each independently hydrogen or an alkyl radical having 1 to 26 carbon atoms, n is 0, 1, 2 or 3, Y is N, P, As or Sb and R⁶ and R⁷ each independently represent hydrogen, alkyl, aryl or aralkyl radicals having up to 40 C atoms or together form part of an aliphatic or aromatic ring system,
    stand or
  • c5) a radical from the group R¹ to R⁵ together with a radical from the group R'¹ to R'⁵ a divalent radical of the formula III represents, wherein A is C or Si and R¹⁰ and R¹¹ each independently represent hydrogen or an alkyl radical having 1 to 24 carbon atoms and a is a value from 1 to about 6
  and or
• d) a compound of formula IV where M 'is M or Mo or W and R¹ to R⁵ can have the meaning given under c1) to c4) and x is 2, 3 or 4 and y is 1 or 2.

Furthermore, the present invention relates to the use of the Invention appropriate composition in the one-step production of isocyanates.

The invention also relates to a method for single-stage production provision of isocyanates from organic nitro or nitroso compounds or mixtures of two or more thereof and carbon monoxide by the Nitro or nitroso compounds or mixtures of two or more of them with carbon monoxide in the presence of a composition of the above be implemented.

The composition according to the invention contains as component a) Metal or a compound of a metal of subgroup VIII Periodic table. If the metals themselves are used, it happens usually in a form in which the metals are as large as possible Have surface. For this purpose, the metals are either extremely fine grind or applied to a carrier material to better Ver division of the catalyst and an increase in its effective surface area to reach. For this purpose, alumina, silica, Coal, barium sulfate, calcium carbonate, asbestos, bentonite, diatomaceous earth  and / or fuller earth can be used. Aluminum is also suitable oxides or zeolites.

Insofar as component a) a metal compound is used suitable oxides, sulfates, nitrates, halides, Carbonates, sulfides or oxalates of the element group mentioned are preserved. In particular compounds of metals of the platinum series, particularly preferred Palladium, rhodium, platinum and iridium halides and their mixtures are preferably used in the context of the present invention. Typi Examples of suitable halides are palladium dibromide and palladium dichloride, palladium difluoride, palladiumdodide, rhodium tribromide, rhodium trichloride, rhodium trifluoride, rhodium trÿodid, platinum tetrabromide, platinum dibro mid, platinum tetrachloride, platinum dichloride, platinum tetrafluoride platinum odide, platinum tetraiodide, ruthenium trichloride, ruthenium tetrafluoride, iridium tribromide, Iridium tetrabromide, iridium trichloride, iridium dichloride, iridium tetrachloride, Iridiumtrÿodid, Iridiumtetrajodid and their mixtures. Likewise, if also not preferred, oxides of the above metals can be used as catalyzes sator can be used. This includes, for example, palladium oxide, Rhodium oxide or platinum oxide. Mixed precious metal Alkali metal halides, such as Na₂PdCl₄.

The use of palladium metal and / or palladium compound is preferred gene, in particular the use of palladium chloride (PdCl₂) preferred is.

In addition to the above com component a) as component b) also organic, preferably aromatic ces, heterocyclic, nitrogen-containing compounds which act as ligands on the Metals or metal compounds described above are coordinated can be present. As a rule, this is a one  five- or six-membered compound containing heteroaromatic ring, which are exclusively nitrogen and carbon, but usually no longer than two nitrogen atoms and at least two double bonds in the heteroaro contains matical ring. Derivatives of this heteroaromatic nitrogen connections can be used. For the purposes of Invention an organic, preferably aromatic, heterocyclic, stick understood compound containing the substituents on the ring such as wise halogen atoms, e.g. B. fluorine, chlorine, bromine and / or iodine atoms, Alkyl radicals with 1 to 40 carbon atoms, aryl radicals, such as phenyl, cresyl and Xylyl residues, olefinic residues, such as allyl and vinyl residues, hydroxyl residues, Mercapto residues, amino residues, alkylamino residues, nitrile residues, oximino residues, Aldehyde residues, ether residues such as aryl, alkyl and alkenyl ether residues, thio ether residues, such as aryl, alkyl and alkenyl thioether residues, carboxyl residues, Carbalkoxy, carbamyl, carboaryloxy or thiocarbamyl bear, the substituents usually up to about 40 carbon atoms, preferably up to about 24 carbon atoms. Also as a ligand The polycyclic analogs of the five- or six-membered can be used heteroaromatic substances, for example, condensed on Benzene ring, a fused cycloaliphatic ring or an ankon densified, nitrogen-containing heteroaromatic ring. Exactly if applicable, although not preferred within the scope of the invention simple salts of the above compounds, for example the proto form, quaternary salts or oxides.

To the heteroaromatic nitrogen compounds and their derivatives, the suitable ligands include, for example, 1-methylpyrrole, 1-phenyl pyrrole, imidazole, 1-methylimidazole, pyrazole, indole, indolenine (3-pseudoindole), 2-isobenzazole, indolizine, carbazole, pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, further monoalkylpyridines such as ethylpyridine, propylpyridine, Isopropyl pyridine, butyl pyridine, isobutyl pyridine or tert-butyl pyridine, 2,6-di  methyl pyridine, 2,4,6-trimethyl pyridine, 4-phenyl pyridine, 2-vinyl pyridine, 2-styryl pyridine, 2-bromopyridine, 2-chloropyridine, 3-chloropyridine, 2,6-dichloropyri din, 2-bromo-4-methylpyridine, 2-fluoropyridine, 2-allyloxypyridine, 4-phenylthio pyridine or 2-methoxypyridine, piccolic acid, nicotinic acid, 2,6-dicyanopyri din, pyridine-2-aldehyde (piccolinaldehyde), 2-aminopyridine, 4-dimethylamino pyridine, diphenyl-4-pyridylmethane, 4-hydroxypyridine, 2-mercaptopyridine, 2-oximino methyl pyridine (piccolinal doxime) or 4-tert-butyl pyridine. Farther can be used quinoline, 2-chloroquinoline, 8-hydroxyquinoline, isoquinoline, Acridine, phenanthridine, 7,8-benzoquinoline, 4H-quinolizine, naphthyridine, Carboline, phenanthroline, benzo [h] isoquinoline, benzo [g] quinoline, benzo [g] iso quinoline, benzo [h] quinoline, benzo [f] quinoline, benzo [f] isoquinoline, 1H-benzo [de] quinoline, 4H-benzo [de] quinoline, 4H-benzo [de] isoquinoline, 1H-benzo [de] isoquinoline, purine, adenine, pteridine, 7H-pyrazino [2,3-q] carbazole, pyrazi no [2,3-d] pyridazine, 4H-pyrido [2,3-c] carbazole, pyrido [1 ′, 2 ′: 1,2] imidazo [4,5-b] quinoxaline, 6H-perimidine or perimidine.

Among the six-membered heterocycles with two N atoms are examples as suitable pyrazine, 4,6-dimethylpyrimidine, 2,6-dimethylpyrazine or Pyridazine. Quinoxaline, 2,3-dimethylquinoxaline, Phthalazine, quinazoline, phenazine or cinnoline.

Examples of simple salts of the nitrogen compounds mentioned above are as the hydrohalides, the hydronitrates, hydrosulfates or Hydroaceta te, such as B. pyridine hydrochloride, 2-chloropyridine-1-oxide hydrochloride, 4-chlorine pyridine hydrochloride or 4,4-dipyridyl dihydrochloride can be used. As a quarter nary salts are suitable for use, for example 1-methylquinolinium chloride, lauryl pyridinium chloride or 1- (4-pyridyl) pyridinium chloride.

Examples of oxides of heteroaromatic nitrogen compounds are Quinoline oxide, pyridine oxide, isoquinoline oxide or imidazole oxides, pyridine-1-oxide,  4-bromopyridine-1-oxide, 2-hydroxypyridine-1-oxide, piccolic acid-1-oxide, 4-meth oxypyridine-1-oxide, 2-bromo-6-methylpyridine-1-oxide, 2- or 4-piccoline-1-oxide applicable.

Preferred as a component in the composition according to the invention b) contain pyridine, quinoline, isoquinoline and / or methylpyridine.

As complexes of heteroaromatic nitrogen compounds with inorganic Compounds can be used, for example, pyridine, quinoline and isoquinones lin complexes, such as (pyridine) ₃FeCl₃, pyridine · SO₃, pyridine · CrO₃, Pyridine · VCl₃, pyridine · V₂O₅ or pyridine · MoO₃.

If necessary, component a) can also be used in such a form in which they already have a complex with an organic, has formed nitrogenous ligands. As organic, nitrogenous Ligands can in particular be the compounds of component b) be set. Such a complex that is not in situ from the component a) and component b) in the composition according to the invention is formed, but is already used in a complex form either used instead of components a) and b) or in addition will. If the nitrogenous ligand is a compound of the component b), the identical or another connection of the Component b) are present. Also as nitrogenous ligands in the Complexes that can be used are ligands derived from compounds of the Component b) are displaced from the complexes. These include ins especially the compounds PdCl₂ (benzonitrile) ₂ and PdCl₂ (NCCH₃) ₂.

Metallocenes can be used as component c) for the purposes of the present invention of the general formula I can be used.

M stands for metals that are capable of at least a cyclopentadienyl radical or a substituted cyclopentadienyl radical enter into a coordinative bond known to the person skilled in the art.

Basically, all metals are suitable for this, which are able to enter into such a bond, but the metals iron, cobalt, Nickel, ruthenium, chromium, manganese, vanadium, titanium, zirconium and / or Hafnium, especially iron as the metallic central atom M before is moving.

As substituents R¹ to R⁵ and R'¹ to R'⁵, the cyclopentadienyls carry a wide variety of substituents. Both Cyclo pentadienyl radicals carry identical substituents, but it is also possible that both cyclopentadienyl radicals are substituted differently. This can both the number and type of substituents, or both Respectively.

In the following, instead of "cyclopentadienyls" or "cyclopentadienyl radicals" also uses the abbreviation Cp. Unless expressly stated otherwise both the abbreviation Cp and the prefix relate  "Cyclopentadienyl-" on both unsubstituted and substituted Cyclopentadienyl residues.

For R¹ to R⁵ and R'¹ to R'⁵, for example, alkyl, aryl or Aralkyl radicals with 1 to 24 carbon atoms can be used. These include ins special methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, Pentyl, hexyl, octyl, decyl, 2-ethylhexyl or higher linear or branched alkyl radicals, such as, for example, hexadecyl or octadecyl radicals. So can, for example, 1,1'-dimethylferrocene, 1,1′-diethylferrocene, 1,1′-diisopropylferrocene, 1,1′-dibutylferrocene, 1,1′-di- tert-butylferrocene, 1-methyl-1'-ethylferrocene, 1-methyl-1'-propylferrocene, 1-ethyl 1'-isopropylferrocene, 1-methylferrocene, 1-ethylferrocene. 1-propylfer rocene, 1-isopropylferrocene, 1-butylferrocene, 1-isobutylferrocene, 1-tert-butyl ferrocene, 1-hexylferrocene, 1-octylferrocene, 1- (2-ethylhexyl) ferrocene, 1-decyl ferrocene, 1-dodecylferrocene or 1-stearylferrocene can be used. As well it is possible that one or both ferrocenyl residues have more than one sub bear stituents. Examples include 1,2: 1 ', 2'-tetramethylferrocene, 1-ethyl 2-methyl-1'-ethyl-2'-methylferrocene or higher substituted analog ga, for example the decamethylferrocene, in which both cyclopenta dienyl rings are completely substituted with methyl groups, in the fiction according to the meaning can also be used. Other connections of the above The person skilled in the art easily obtains species by exchanging hydrogen atoms against suitable alkyl radicals in the cyclopentadienyl rings, for which Use of the respective cocatalyst parameters such as accessibility and Solubility in different solvents are decisive.

In addition to the linear or branched alkyl radicals, the cyclopenta dienyl units are also substituted by suitable aryl or aralkyl radicals be. These include, for example, phenyl, naphthyl, anthryl or phen anthryl residues, both cyclopentadienyl rings with one or more of the  mentioned substituents with the same or different pattern sub can be substituted. The aromatic substituents can in turn carry further substituents, linear and / or branched alkyl radicals are preferred. Mixed substitution of cyclo is also possible pentadienyl rings with alkyl, aryl and / or aralkyl radicals.

Another in the context of the present invention as component c) Leading compound class with heterocyclic are leading to good results Residues substituted metallocenes.

In particular, it is preferred if as heterocyclic substituents such substituents are used as component b) in the inventions composition according to the invention may be present. This includes all of the above mentioned ligands, pyridine in particular being preferred as a substituent is. To what is preferably used in the context of the present invention heterocyclically substituted metallocenes include, for example, 2-ferrocenyl pyridine, 3-ferrocenylpyridine and 4-ferrocenylpyridine. It is also possible the use of on both cyclopentadienyl rings with substituents from the suitable for use as component b) suitable group substituted metalloce NEN such as 1,1'-bis (3-pyridyl) ferrocene. The use of Ferrocenes substituted with mixed ligands possible.

The radicals R¹ to R⁵ and R'¹ to R'⁵ can be used in the sense of the present Invention also part of a condensed, aromatic, optionally be hydrogenated or partially hydrogenated ring system.

These include, for example, indenyl residues, which are themselves alipha may be substituted table and / or aromatically. It is also possible that pairs of residues R¹ to R⁵ and / or R'¹ to R'⁵ Are part of a heterocyclic ring system, so that this heterocyclic  Ring system optionally as a ligand for the catalyst used can act. In this case, nitrogen atoms are present as heteroatoms moves.

The metallocenes which can be used according to the invention can either be used alone or together with the already discussed substituents also substituents of the general formula II

carry. Here Y stands for nitrogen, phosphorus, arsenic and / or antimony, preferably by a "spacer" X of the respective cyclopentadienyl ring is separated. Alkylene and / or are particularly suitable as spacers Dialkylsilylene residues. The dialkylsilylene residues can, depending on desired effect, such as solubility, with alkyl radicals 1 to 26 carbon atoms can be substituted, but usually lower molecular alkyl radicals with for example 1 to 4 carbon atoms and in particular with a carbon atom are preferred. In particular, within the present invention, however, alkylene radicals with 1 to 4 carbon atoms sets, with methylene and / or ethylene radicals being preferred. The heteroato me Y usually carry further substituents (R⁶, R⁷) for Are hydrogen and / or alkyl, aryl or aralkyl radicals. You can also the radicals R⁶ and R⁷ together represent a cyclic system.

For the purposes of the present invention, such substituents are preferred Formula II in which X is CH₂ or Si (CH₃) ₂ and Y is nitrogen.

Furthermore, so-called "ver bridged metallocenes "can be used as component c)  Metallocenes each correspond to a group R¹ to R⁵ together with a radical from the group R'¹ to R'⁵ a divalent radical of Formula III mentioned above, wherein A is carbon or silicon and R¹⁰ and R¹¹ for hydrogen and / or alkyl radicals with 1 to 24 carbon atoms stand. Such residues of the formula III are used in particular as a bridge sets, in which A for carbon and the radicals R¹⁰ and R¹¹ for water substance and a stand for values of 2 or 3.

Furthermore, instead of or together with component c) as Component d) for carrying out the present invention compounds of the formula IV mentioned at the outset, where M is already has the meaning given. The compounds of formula IV are are so-called "half-sandwich complexes" in which compared to the above-mentioned compounds by a cyclopentadienyl Carbon monoxide residue is replaced. The number x is the coordinative bound carbon monoxide molecules depending on the metal used, where in the case of the preferably used metal atoms two, three or four carbons monoxide residues can be complexed. Examples of as component d) Compounds that can be used are, for example, (C₅H₅) Co (CO) ₂, (C₅H₅) V (CO) ₄ or (C₅H₅) Mn (CO) ₃.

If appropriate, the compounds of the formula IV can also be dimeric Form are present so that a dinuclear Cp metal-carbonyl complex ent where y stands for the number 2. In the case of the preferred one As a rule, two carbon monoxide molecules are complexed with iron, so that x stands for the number 2 and y for the number 2.

These include in particular compounds of the formula [(C₅H₅) M (CO) _n ] ₂, such as, for example, [(C₅H₅) M (CO) ₂] ₂ (M = Fe, Ru), [(C (H₅) W (CO) ₃] ₂ or [(C₅H₅) Ni (CO)] ₂.

Is used as component d) a compound of general formula IV sets, the cyclopentadienyl radical (s) can be substituted by one or more re of the above-mentioned substituents.

In the sense of the present invention, it has proven to be advantageous if the compounds used as components c) or d) are none Bear substituents. In this case, the radicals R¹ to R⁵ and R'¹ to R'⁵ hydrogen, the preferred substance being ferrocene (Bis (cyclopentadienyl) iron (II)) is used.

The invention also relates to a method for single-stage production provision of isocyanates from organic nitro and / or nitroso compound gene by the nitro and / or nitroso compounds with carbon monoxide in Presence of the composition according to the invention as defined above be implemented.

As a starting compound for the process according to the invention, any organic nitro compound that convert into an organic isocyanate lets be used. In general, aromatic, cycloaliphatic and aliphatic mono- or polynitro compounds, which may also be can be substituted, according to the inventive method in the corresponding mono- and / or polyisocyanates are transferred. The Be Drawing "organic nitro compound" includes in the description as in unsubstituted as well as substituted organic nitrover bindings of the above types. Can also be used in the sense of Organic nitroso compounds, although the Use of nitro compounds is preferred. Examples of suitable nitro Compounds that can be converted into isocyanates according to the invention for example aromatic nitro compounds such as nitrobenzene, dinitrotoluene, Nitronaphthalenes, nitroanthracenes, nitrodiphenyls, bis (nitrophenyl) methanes,  Bis (nitrophenyl) ether, bis (nitrophenyl) thioether, bis (nitrophenyl) sulfone, Nitrodiphenoxyalkanes and / or nitrophenothiazines. Also as a substrate in For the purposes of the present invention, nitrocycloalkanes such as for example nitrocyclobutanes, nitrocyclopentanes, nitrocyclohexanes, dinitro cyclohexane or bis (nitrocyclohexyl) methane.

Nitroalkanes, for example, are also suitable for the reaction Nitromethane, Nitroethane, Nitropropane, Nitrobutane, Nitrohexane, Nitrooc tane, nitrooxadecane, dinitroethane, dinitropropane, dinitrobutane, dinitro hexanes, dinitrodecanes, phenyl nitromethanes, bromophenyl nitromethanes, nitro phenyl nitromethanes, methoxyphenyl nitromethanes, bis (nitromethyl) cyclohexanes or bis (nitromethyl) benzenes. All mentioned connections can be made with be substituted by one or more additional substituents, such as nitro, Nitroalkyl, alkyl, alkenyl, alkoxy, aryloxy, alkylthio, arylthio, Carboxyalkyl, cyan or isocyanate groups or halogen atoms, and can thus serve as starting compounds in the new process.

Specific examples of appropriately substituted and usable organic Nitro compounds are o-nitrotoluene, m-nitrotoluene, p-nitrotoluene, o-nitro-p-xylene, m-dinitrobenzene, p-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoiuol Dinitromesitylene, 4,4, -dinitrodiphenyl, 4,4-dinitrodibenzyl, bis- (p-nitrophe nyl) methane, bis (2,4-dinitrophenyl) methane, bis (p-nitrophenyl) ether, bis (2,4-di nitrophenyl) ether, bis (p-nitrophenyl) sulfone, o-nitrophenyl isocyanate, m-nitro phenyl isocyanate, p-nitrophenyl isocyanate, 1,6-dinitro-n-hexane or 1,4-bis (nitromethyl) cyclohexane.

In addition, isomers and mixtures of these organic Connections are used, as are homologs and other ver turned connections.  

The method according to the invention is particularly effective in the transfer aromatic nitro compounds in the corresponding isocyanates. The Be Drawing "aromatic nitro compounds" refers to such aromati Nitro compounds that have at least one directly attached to an aromatic Carbon-bound nitro group contain, the aromatic Carbon ring can still be substituted as indicated above. Preferred organic nitro compounds used in the invention are nitrobenzenes, both the mono- and the Including polynitrobenzenes and their mixtures of isomers, nitroalkylbenzenes Lich of the various nitrated toluenes and nitrided xylenes, nitrated Diphenyl and nitrided diphenylmethane. Generally the organi contain Nitro compounds as well as the substituted organic nitrover bonds between 1 and about 20 carbon atoms, preferably between about 6 and about 14 carbon atoms.

The inventive method can in the absence of a solvent be carried out, however, better yields of organic Isocyanates obtained when the reaction in a solvent that is inert to the components of the reaction system. As Inert solvents are preferably linear and / or branched alkanes with 6 to 12 carbon atoms, aromatics, halogenated aromatics, aromatic Ether and / or commercially available hydrocarbon mixtures used. Examples for this are n-heptane, cyclohexane, benzene. Toluene and xylene, halides, aromatic hydrocarbons, such as monochloronaphthalene, monochlorobenzene, Dichlorobenzene and / or trichlorobenzene. The preferred solvents that can be used in the context of the present invention count Toluene and o-dichlorobenzene.

The amount of inert solvent affects the feasibility of method according to the invention does not exert a great influence, is preferably  the proportion of nitro and / or nitroso compound to be converted in relation about 5 to 40% by weight of the solvent, particularly preferably about 5 up to 20% by weight.

The implementation is usually in a suitable pressure vessel, e.g. B. an autoclave with a stirrer or shaker is provided. For the implementation of the reaction should be in the As a rule, attention should be paid to inert reaction conditions, especially the Largely excludes the presence of water or hydrogen. One little or no influence on the course of the invention The process exerts the initial presence of carbon dioxide. For The reaction vessel should for example the autoclave, before, during or after loading the solid and liquid reaction components with an inert gas, such as for example nitrogen or argon.

The autoclave is expediently filled after the filling and / or liquid reaction components filled with carbon monoxide. Here is usually at a pressure between about 20 and about 500 bar, preferably between about 100 and about 400 bar and particularly preferred between 140 and 250 bar at a temperature between 150 and 250 ° C set. Generally the amount of carbon monoxide is in the free space of the reactor is insufficient to maintain the desired pressure received and also supply carbon monoxide to the extent that Reaction progresses. Therefore you usually have to add carbon monoxide Lich intermittent or continuous as the reaction progresses, deliver to the reactor.

The reaction temperature is usually above 23 ° C, usually between about 130 ° C and 300 ° C. Reaction temperatures of  about 150 ° C to 250 ° C, with temperatures from about 180 ° C to about 230 ° C are particularly preferred. As a rule, the pressure should be at Carrying out the reaction be about 20 to about 500 bar.

The reaction time depends on the organic nitro or Nitroso compound, temperature, pressure and the amount used the composition of the invention as well as the applied equipment. Usually you need to do it in batches between about 0.25 and about 10 hours to achieve the desired reaction degree, but it can also have shorter or longer reaction times be respected. Are preferred in the context of the present invention Response times from about 0.5 to about 6 hours, and particularly preferred from about 0.5 to about 3 hours.

The ratio of nitro and / or nitroso groups to component a) should usually around 10,000: 1 and about 5: 1. Preferably lies the ratio at about 1000: 1 and about 10: 1 and especially before between about 100: 1 and about 20: 1.

The molar ratio of component a) to component c) or com component d) is generally between approximately 20: 1 and approximately 1:20, ratios from about 10: 1 to about 1: 5, and especially about 5: 1 to about 1: 1 are preferred.

In the context of the method according to the invention, it is also possible that the isocyanates formed in the reaction mixture immediately to mono- and / or Polyurethanes are implemented. Amongst these are polyurethanes not to understand macromolecular compounds, but low molecular weight compounds that carry more than one urethane group. This usually happens in that the implementation in the presence of a  Alcohol is carried out with the resulting isocyanates immediately reacted further to the corresponding urethane.

As alcohols which can be used in the sense according to the invention, are, for example, the monofunctional alcohols, such as methanol, ethanol, Propanol, butanol, pentanol, hexanol, heptanol or octanol, and ver branched aliphatic monofunctional alcohols, such as Isopro panol, isobutanol, tert-butanol or 2-ethylhexanol are suitable. Likewise a higher aliphatic alcohols, for example decanol, dodecanol, Tetradecanol, hexadecanol or octadecanol. Are also suitable in aromatic alcohols, such as phenol, or substituted phenols, such as methylphenol, ethylphenol, propylphenol, Isopropylphenol, butylphenol, isobutylphenol or tert-butylphenol, and phenols substituted with higher alkyl groups. Unsuitable in the sense of present invention are, for example, nitro- and / or nitrosophenols, since they are implemented in the sense of the invention described polymeric products.

In addition to or instead of the monofunctional alcohols are optionally polyfunctional alcohols such as glycols or higher functional alcohols, such as trimethylolpropane, pentaerythritol or carbohydrates. In this case, however, the stoichio metric ratio between alcohol and nitro or nitroso groups be respected. If the polyfunctional alcohol is used in excess for example 1 mol of alcohol per mol of nitro or nitroso group, so ent are molecules that also contain OH groups in addition to methane groups. Puts the nitro or nitroso component in excess, for example 1 mol of nitro or nitroso compound per mol of hydroxyl group, so arise in In the case of monofunctional nitro or nitroso compounds completely Alcohols reacted with urethane groups; with polyfunctional nitro or  In addition to the urethane groups, nitroso compounds also contain isocyanate groups in the molecule.

The following examples serve the process according to the invention to explain in more detail and are not a limitation.

Examples

An autoclave was with the amounts given in Table 1 in the Substances listed in the table. In Examples 1 to 8 and in Comparative Examples A and B an autoclave with 235 ml Volume used. In Example 9, the volume of the autoclave was 300 ml and in Example 10 100 ml. The autoclave was based on the in Table 1 specified temperature heated, and then became carbon monoxide pressed up to the pressure specified in Table 1. The reaction mixture was for the time period specified in Table 1 at this temperature held, spent carbon monoxide was injected. Subsequently the reaction mixture was cooled and let down. The analysis of the Discharge was carried out by means of gas chromatography. The total turnover as well as the Selectivity of the reaction to the corresponding end products are also Table 1.

Legend for table 1:

1 = o-dichlorobenzene
2 = toluene
3 = not determined
4 = after 30 min .: 97%
5 = total selectivity to mono nitro and diisocyanates
6 = 1: 1 mixture of 2- and 4-nitro toluene
7 = A further 5 g of 2,4-dinitrotoluene were then added and the reaction was repeated under the same conditions.
Total sales of the second run: 91%,
Selectivity to 2,4-tolylene diisocyanate and to 2,4-tolylene nitroiso cyanate: 64%.

Claims (11)

1. Composition at least

• a) a metal or a compound of a metal of VIII. Subgroup of the periodic table,
• b) an organic, heterocyclic, nitrogen-containing compound,
• c) a compound of formula I. where M is Fe, Co, Ni, Ru, Cr, Mn, V, Ti, Zr or Hf and the radicals R¹ to R⁵ and R′¹ to R′⁵ are each independently of the other
  • c1) hydrogen,
  • c2) an alkyl, aryl or aralkyl radical having 1 to 24 carbon atoms
  • c3) a fused-on aliphatic or aromatic or heterocyclic ring system with up to 40 C atoms, which in turn can each be aliphatic or aromatic substituted,
  • c4) a substituent of the formula II where each X is CR⁸R⁹ or SiR⁸R⁹, where R⁸ and R⁹ are each independently hydrogen or an alkyl radical having 1 to 26 carbon atoms, n is 0, 1, 2 or 3, Y is N, P, As or Sb and R⁶ and R⁷ each independently of one another represent hydrogen, alkyl, aryl or aralkyl radicals having up to 40 C atoms or together form part of an aliphatic or aromatic ring system,
    stand or
  • c5) in each case one radical from the group R¹ to R jeweils together with one radical from the group R′¹ to R′⁵ a divalent radical of the formula III represents, where A is C or Si and R¹⁰ and R¹¹ each independently represent hydrogen or an alkyl radical having 1 to 24 carbon atoms and a is from 1 to about 6
    and or
• d) a compound of formula IV where M 'is M or Mo or W and R¹ to R⁵ can have the meaning given under c1) to c4) and x is 2, 3 or 4 and y is 1 or 2.

2. Composition according to claim 1, characterized in that as Component a) palladium metal and / or a palladium compound is included. 3. Composition according to one of the preceding claims, characterized characterized in that as component a) Pd, PdCl₂, PdBr₂, PdI₂ NaPdCl₄, PdCl₂ (benzonitrile) ₂, PdCl₂ (NCCH₃) ₂ and / or PdCl₂ (pyri din) ₂ is included. 4. Composition according to one of the preceding claims, characterized characterized in that X in formula II is CH₂ or Si (CH₃) ₂. 5. Composition according to one of the preceding claims, characterized characterized in that Y in formula II is nitrogen.   6. Composition according to one of the preceding claims, characterized characterized in that the radicals R¹ to R⁵ and R'¹ to R'⁵ for water stand fabric. 7. Composition according to one of the preceding claims, characterized characterized in that M stands for iron. 8. Composition according to one of the preceding claims, characterized characterized in that as component b) pyridine, quinoline, isoquinoline and / or methyl pyridine are included. 9. Use of a composition according to one of the preceding Claims for the production of isocyanates. 10. Process for the preparation of isocyanates from organic nitro and / or Nitroso compounds in which the nitro and / or nitroso Carbon monoxide bonds in the presence of a composition be used according to one of the preceding claims. 11. The method according to claim 10, characterized in that it is carried out using one or more of the following process parameters:

• a) reaction between a temperature of 130 and 300 ° C;
• b) reaction at a carbon monoxide overpressure of 20 to 50 bar;
• c) duration of the reaction 0.25 to 10 hours;
• d) The molar ratio of nitro and / or nitroso groups to component a) is between 10,000: 1 and 5: 1;
• e) The reaction is carried out in the presence of an alcohol.