DD145631A1 - Process for the preparation of aromatic isocyanates - Google Patents

Abstract

The aim of the invention is an improved method for economical production of aromatic isocyanates by Reaction of aromatic nitro compounds with carbon monoxide, the with relatively small amounts of precious metals in the catalyst system expires while the catalyst system remains active. For this one sìetzt aromatic nitro compounds with carbon monoxide under im essential water and hydrogen-free conditions elevated temperature (160 to 300 ° C) and elevated pressure (20 to 600 at) in the presence of a catalyst system consisting of palladium and / or Rhodium and / or at least one compound of these precious metals, at least one iron halide complex of the general formula ÄkFelXmLn and / or suitable starting substances for the formation of these Eisenhalogenidkomplexe under Reaktionsbadingungen. In the Formula X = halogen, L = aromatic nitrogen-containing heterocyclic ligand, A = an organic. Cation and k, l, m, n are integer indices with k, n = 0 and l, m = 0.

Description

The invention relates to an improved process for the preparation of aromatic isocyanates from aromatic nitro compounds and carbon monoxide in contrast to a new catalyst system.

Aromatic isocyanates are required in large quantities for the preparation of medicaments, herbicides and, above all, polyurethanes. They are produced industrially by phosgenation of amines, which are obtained by reduction of the corresponding nitro compound. The use of phosgene and thus of chlorine, which does not appear in the final product, more expensive this two-stage process and brings environmental protection problems with it.

Characteristics of the known technical solutions

There has already been a process for the direct conversion of aro-r ranic nitro compounds with carbon monoxide to aromatic isocyanates in the presence of a noble metal catalyst according to the formal reaction equation

R-UO ₉ + 3 CO ^^ - R-NCO -§- 2 C0 "proposed * However, this method can not technically

be used, since with the described catalyst only traces of aromatic isocyanates are formed. In many of the following patents, slightly improved catalysts are described which are intended to enable a technical utilization of the process. , Thus, the use of mixed catalysts is described which contain at least one palladium or Rhodiumhalogeiiid and at least one oxide of the transition metals V, Mo, V / o, Wb, Cr or Ta. As oxidic component and Fe ₂ O ^ can be used. Furthermore, a catalyst system of a noble metal halide, an aromatic nitrogen-containing heterocyclic compound and these transition metal oxides is described.

But even with these catalysts, an economic process is not possible · The catalysts lose their activity by reduction of the noble metal and are usually only 1 to 3 times discontinuous applicable «Therefore, an addition of pyridine hydrochloride has been proposed to re-deposited under reaction conditions metallic palladium to transform active complexes.

However, with these, and also with the aforementioned catalyst systems, usually sufficient selectivity is not achieved. Thus, in the reaction of 2,4-dinitrotoluene (DIiT) in the presence of palladium black, pyridine hydrochloride and oxygen-containing oxidants, only 21 to 33 % of the industrially interesting toluylene-2,4-diisocyanate (TDI) is obtained at a DNT conversion of 88 to 92%.

It is particularly disadvantageous that, for most of these processes, relatively large amounts of the expensive noble metal coronaut must be used in order to obtain TDI in acceptable yields. So vsird. B. a molar ratio of DNT: PdCl ₂ »16.5: 1 needed to obtain in the presence of the catalyst system PdC1 ^ / pyridine / feMoJ ^^ A 76 % TDI yield. At a molar ratio DKT: ^pdcl 2 ^s 33 ϊ 1, only 42 % TDI is produced with this catalyst system.

Object of the invention

The aim of the invention is to develop an improved process for the economical production of aromatic isocyanates.

presentation; the essence of the invention

The invention has for its object to develop a process for the preparation of aromatic isocyanates with good yields.

According to the invention, the object is achieved in that in semi-continuous process implementation aromatic nitro compounds with carbon monoxide under substantially water and hydrogen-free conditions at elevated temperatures and elevated pressure in the presence of a catalyst system consisting of palladium and / or rhodium and / or at least one compound of these Noble metals or at least one Eisenhalogenidkompiex of the general formula A, Pe-JC L

X = halogen

L = aromatic nitrogenous ,. heterocyclic

ligand

A = organic cation k, l, m, n = integer indices k, n »0 l, m - 0

Examples of X, halogens are chlorine, bromine and iodine, preferably chlorine. Examples of L, aromatic nitrogen-containing heterocyclic ligands, are the compounds pyrrole, imidazole, byrazole, indole , Carbazole, pyridine, pyrazine, pyrimidine, pyrazide, quinoline, isoquinoline, acridine, naphthyridine, phenanthroline, purine, adenine, and their derivatives. In the description and the claims

- 4 * *

printing "suitable starting materials for the formation of the invention egg senhalogenidkomplexe" on such aromatic nitrogen * heterocyclic compounds. The term "derivatives" in the specification and claims refers to substituted aromatic nitrogen-containing heterocycles having predominantly the following substituents

- Halogen atoms, such as fluorine, chlorine, bromine and iodine

- Alkyl radicals, such as the methyl, ethyl, propyl, isopropyl, η-butyl, sec-butyl, isobutyl and tert-butyl group

Aryl radicals, such as the phenyl, naphthyl, tolyl and xylyl groups

- heteroaryl radicals, such as the pyridyl group

Aralkyl radicals, such as the benzyl group

- olefiniscjie radicals, such as the allyl and viny! group

- Alkylamino groups

- Ether groups

- Thioether groups.

Examples of A, organic cations are

- quaternary Ainiaoniumionen, \ uie tetramethylammonium, tetraethylammonium _s tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, !!, Hjli-triethyl-N-benzylammonium soviie K-alkylated tertiary aromatic nitrogen-containing heterocycles and their derivatives,

- protonated tertiary amines, vJie trimethylammonium, triethylammonium »tripropylammonium, tribia.tylammonium, tripentylammonium, dicyclohexylethylammonium and K-protonated tertiary aromatic nitrogen-containing heterocycles and their derivatives / *

Preferably, the organic cation A and the aromatic nitrogen-containing heterocyclic ligand L are chosen so that the resulting Eisenhalogenidkomplex is adequately soluble under the reaction conditions in each case applied solvent * Particularly effective catalyst systems are obtained by the

, , '. , - 5 *

Application of the following iron halide complexes, · and / or their suitable starting substances

Iron (II) complexes

₂ ^, PeCl ₂ (py) ₂ , FeCl ₂ (Py) ₄ , ZT ^ e (Py ') 6-7 ^cl 2 andthe analogous complexes with quinoline and isoquinoline; (pyH) ₂ FeCl. ² ', (BU ₄ H) ₂ PeCl.- "as well as the analogous complexes with quinolinium and isoquinoliniunications or other quaternary ammonium ions;

Iron (III) complexes PeCl ₃ (py), PeCl ₃ (Py) ₂ ,

and the analogous complexes with quinoline and isoquinoline (PyH) PeCl ₄ , (PyH) ₃ Pe ₂ Cl ₉ = 2 (PyH) PeCl ₄ .pyHCl, (pyH) ₂ Fe ₂ Cl ₈ (py) ₂ and the analogous complexes with quinolinium and isoquinolinium cations or quinoline and isoquinoline ligands; (Acrid.H) _? -

⁴ ^ = (Acrid.H) PeCl. e (Acrid "H) Cl and (Bu ^ N) PeCl, as well as analogous complexes with other quaternary ammonium ions.

1) py = pyridine; 2) pyH = pyridinium; 3) Bu = n-butyl; 4) (Acrid.H) = acridinium '

These iron complexes as catalyst component according to the invention are compounds known per se, the preparation of which is readily achieved by the processes described in the literature ZT-S7. The term "suitable starting substances for the formation of the iron halide complexes of the invention" in the description and the claims further refers to iron halides, halo-fererrates or the substances which form them, and the halides of the organic cations already described. The molar ratio, in which the suitable starting substances are used to form the iron halide complexes according to the invention, is largely freely selectable. "" In general, stoichiometric amounts are used. "Often it is but beneficial, a surplus

of aromatic nitrogen-containing heterocyclic compound with respect to the iron halide or haloferrate. Palladium and / or rhodium, as finely divided metals, may be applied to an inert support. Examples of this are psyllium black for black palladium on barium sulphate or carbon »

According to the invention, the palladium and / or rhodium compound to be used is largely freely selectable. "The oxidation state of these precious metals in the compound used and their initial solubility in the reaction medium is not critical."

However, it is based on such compounds of these noble metals, which react under reaction conditions with the erfinaungsgemäßen iron complexes on soluble, active catalyst complexes. Examples of such compounds are:

Halides such as PdCl ₂ , PdBr ₂ , RhCl ₃ , RhBr ₃

- Oxides or oxide hydrates, such as PdO, PdOoH ₂ O ₃

- Complexes, like

Bis (dibenzylideneacetone) palladium (O), dichlorobis (benzonitrile) palladium (II), dichlorobis (pyridine) palladium (II), chloro-bis (quinoline) palladium (II), dichlorobis-ds-quinoline) palladium (II), bis -CpyridiniumJtetrachloropalladatClI) (C ₅ H ₅ IIh) ^ ^ PdCl, bis "(li ^, H-triethyl-l-benzylammonium) tetrachloropalladate (II) / JC ₂ H _{5) 3} H (C ₇ H ₇ 27ZP <ICL ₄ _7 , Bis ~ (tetra-n-butylammonium hexachlorodipalladate ClI) /, ^ .Hg) .e7 ₂ ~ / PdgClr 7 and analogous rhodium complexes

<* Carbonyls, as Palladiufficarbonylchlorid / P _n "dCl (C027, rhodium carbonyl chloride / Rh ₂ Cl ₂ (CO), J

Essential to the superiority of the process of the invention over other processes for the preparation of aromatic isocyanates from aromatic compounds and carbon monoxide is the stability of the soluble, active catalyst complexes, consisting of metallic palladium and / or rhodium and / or at least one compound of these precious metals and the iron halide complexes according to the invention form under the reaction conditions.

._ ₇ _.,. 5 2If;

Due to certain reaction conditions, the soluble, active catalyst complexes remain effective even with repeated use, and deactivation by deposition of metallic palladium and rhodium can be avoided. In the presence of the catalyst system described, it is possible to use aromatic nitro compounds with carbon monoxide according to the invention. be reacted aromatic isocyanates. As starting compounds for the process of the invention it is preferred to use those aromatic nitro compounds which contain from 6 to 20 carbon atoms per molecule. However, it can also be any other aromatic Mtroverbindung, which translate into an aromatic isocyanate, can be used. In general, substituted and unsubstituted aromatic mono-, di- and polynitro compounds are used as starting compounds. Examples of such aromatic nitro compounds are litrobenzol, 1- and 2-Kitronaphthalin, o-, m ~, p-lTitrotoluol, o-, m-, p _f ~ ChXorbenzol, Hitromesitylen, dinitrobenzene, 1-chloro, "2,4-dinitrofcenzol, 2, 4-Dinitrotoluene, 2,6-dinitrotoluene, 4,4 '* Dinitropheny! Methane, 4,4'-Dinitrodiphenyläthex, 2,2', 4f4 '~ Tetranitrodiphenylmethan. Di- or Polyiiitroverbindungen whose nitro groups have already been partially converted into isocyanate groups, such as 2-nitro-4-isocyanatotoluol and 4-Ni ~ t ~ 2-isocyanatotoluene can be used as starting compounds · This is the case when the method of Invention is carried out continuously in the cycle or discontinuously, batchwise and incompletely reacted aromatic di- or Polynitroverbindungen back again in the processββ

The molar ratio of nitro groups (-IiOg) to be converted to the iron halide complex and the noble metal {p & QgJ : (JeJ : / M7 (M => Pd, Rh) is variable.) Most commonly, a molar ratio of ^ -ΕΟ ₂ _7: / Fe / : / M / ^{from 1:} L " ^s 1 ^to 10000: 10: 1, preferably from 100: 4: 1 to 3000: 30: 1, to obtain the desired stability of the catalyst system." To deactivate by deposition of metallic palladium and rhodium It is still necessary to avoid sales

8- «ag · *

of the aromatic Sitro compound used only to a certain degree depending on the particular molar ratio used / PJOFJ / m7. '

The carbon monoxide used may optionally also contain carbon dioxide and other inert gases in certain amounts. However, the carbon monoxide should be substantially free of water and hydrogen. Bas's method of the invention also proceeds with hydrogen-containing carbon monoxide, but the described stability of the catalyst and the catalyst described are selective isocyanate formation substantially only achieved when the hydrogen content of the carbon monoxide is less than 0.1 vol # - #, preferably less than 0.01 vol. -% is _o

To convert a nitro group requires 3 moles of carbon monoxide, but in practice one works with an excess of carbon monoxide. The molar ratio to be applied / ßO7 t ~ Z. "- ^ Qo_7" ^ i ^ d is essentially determined by whether the process viirde carried out batchwise or continuously

A suitable discontinuous embodiment of the process of the invention consists for example in the fact that the reaction partners and the catalyst system are placed in an autoclave or in a similar pressure vessel. In this embodiment, the carbon monoxide can also be continuously replenished during the reaction time.

A suitable continuous embodiment of the process of the invention consists, for example, in contacting the reaction partners and the catalyst system during passage through a reaction tube. In both the discontinuous and continuous embodiments, the required stability and selectivity only becomes · Achieved when the material of the reaction vessel is inert under reaction conditions towards the reactants and the catalyst system, or if the reaction vessel is internally lined or coated with a suitable inert material.

The process of the invention can be carried out without a solvent. However, it is often advantageous to add a solvent.

way. Suitable solvents are organic nitriles, liquid aromatic hydrocarbons such as benzene _y toluene, xylenes and liquid, halogenated, aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene ©, 1-chloronaphthalene, di- and polychlorinated diphenyl ether, chlorinated: diphenylinethane and chlorinated diphenyl · The concentration of the aromatic Kitroverbindung in the solvent is variable, is preferable to add 5 to 50% solutions of reacting a · the reaction requires in the present invention the application of elevated temperature and pressure * Suitable reaction temperatures between 160 ⁰ C and 300 ⁰ C, preferably between 180 ⁰ C and 260 ^° C. Suitable reaction pressures above 20 at, preferably between 50 at and 600 at "

The reaction time depends on the temperature, the pressure, the amount of catalyst used, the aromatic ITitro compound used, the type of reaction vessel and the desired conversion. Generally, the discontinuous embodiment of the process of the invention requires reaction times of half an hour up to 24 hours .

Kach the reaction, the reaction mixture can be worked up by various separation methods. Examples of separation methods are distillation (prection) and selective extraction. Preferably, the formed aromatic isocyanate is distilled from the reaction mixture when the boiling point difference between the aromatic isocyanate and the aromatic urotro compound allows this separation. In this case, one works without or with a high-boiling solvent whose boiling point is possibly still above the boiling point of the aromatic Uitroverbindung used. In this way, unreacted or incompletely isactivated aromatic Hitro compounds remain dissolved in the distillation residue together with the catalyst system and can be used again for the reaction.

The process of the invention has the advantage that selective formation of aromatic isocyanates in good yields

μ 10 ρ-

in the presence of a catalyst system. The catalyst system according to the invention contains only relatively small amounts of noble metal, is highly stable and has the advantage that it remains active under reaction conditions and can be used repeatedly.

The invention will be explained in more detail below with reference to 81 examples.

Example example t

Preparation of phenyl isocyanate from nitrobenzene

In a special glass insert, 0.110 g of bis (tetra-n-butylammonium) -di- chloro-tetrachlorodipalladatill) (Bu ₄ N) ₂ -PdpGlg and 1.42 g of isoquinolinium tetrachloroferrate (III) (Isochin.H) PeGl, in 50 ml of nitrobenzene solved. The fill level of 50 ml was indicated on the glass insert. "The glass vessel thus charged was placed in a 500 ml steel autoclave." In the sealed autoclave, 3 times 50 atms of hydrogen-free carbon monoxide were injected for rinsing. After that carbon monoxide was forced to the outlet pressure of 180 at once and the autoclave used in a container heated to 250 ⁰ C heating block "While -. The reaction was heating block and autoclave moved by a shaker" The pressure rose to 264 at After hours, the autoclave was taken from the heating block and cooled, after relaxing and opening the glass insert was removed and connected via a Schliff connection with the 50 cm column of a vacuum distillation apparatus. At a pressure of 20 Torr so 5.7 g of phenyl isocyanate were distilled off. Thereafter, nitrobenzene was topped up to the 50 ml mark of the glass insert and this used as described again and repeatedly for the reaction. When used six times, the following quantities of phenyl isocyanate (PhNCO) were recovered

Use: Ί »2« 3 »4« 5o 6, total

^m PMfff! nZi7 5.7 6.0 6.0 6.2 6.2 6.0 4.0 34.1

- 11 -

Embodiment 2

i S ΊΑΊ

• ^ & * v & ff

Example 1 was repeated in the manner described with the difference that p-Hitrotoluol was used as a 30% solution in -Chlornaphthalin · 100 ml of this solution were together sit sit the described catalysts in the described manner, wherein each after the vacuum distillation so much p Citrotoluene was added again as p-tolylisocyanai (p-Tl) was recovered by distillation:

Commitment; 1 _O 2. 3. 4 «5« 6. 7. Total

³ » ^{9 4} » ^{6 5} »° ⁴ » ^{8 5} »° ⁵ » ° ⁴ ' ^{4 32} » ⁷

The two-part and percentages in Examples 3 x to 81 are by weight. The indicated yields of aryl isocyanates relate to the amount of the respective nitro-compound used ·

Example 3

Into a glass insert were added 1.82 g (10 min) of 2,4-dinitrotoluene (DNT), 7.38 g of o-dichlorobenzene (o-DCB), 33.6 mg (0.1 mmol) of di-chlorobis ( pyridine) palladium (II) PdCl ₂ (py) ₂ and 67 mg (0.1 mmol) (PyH] UFe ₂ Cl _0. The glass vessel thus charged was placed in a stainless steel autoclave whose reaction space volume was 80 ml. IAAL 50 at hydrogen freiee carbon monoxide were in the sealed autoclave then to flush 3 pressed in. After that again pressed hydrogen-free carbon monoxide until the output pressure 250 at one. then put it the autoclave preheated to 260 ⁰ C heating block a · During the reaction, heating block and The autoclave was moved through a shaker, the pressure rose to 348 ° C during the run, and after 3 hours, the autoclave was removed from the heating block and cooled, and after being let down and opened, the contents of the glass were analyzed by gas chromatography.

· * 12 *

215 247

100 % conversion of 2,4-dinitrotoluenes (DKT), 59 % yield of toluylene ~ 2,4-diisocyanate (TDI) 28 % yield of monoisocyanates (2-isocyanato-4-nitrotoluene, 2-hitro-4-isocyanatotoluene)

Embodiment 4

Example 3 was repeated as described, with the difference that 16 ₉ 8 mg (0.05 mmol) of PdCl ₂ (py) _{2 were} used. · All other amounts remained as described in Example 3. Result:

DNT conversion: 100 % TDI yield: 48 % monoisocyanates: 35 %

The following 2 examples were carried out comparatively, the catalysts used are not the subject of the invention. However, the results of these examples demonstrate the superiority of the process of the invention over other processes employing these catalysts,

Ausführun gsbeispiel 5

The embodiments 3 and 4 were in the manner described was repeated with the exception that _S 8 mg (0.05 mmol) PdCl 'were used ^e 2 ⁰ 3 "result.:' ₂ (py) and 0.14 g of ⁱ as the catalyst 16

DHI ~ conversion 45% TDI yield 3 % monoisocyanates 33%

Embodiment 6

The working examples 3 and 4 were repeated as described, with the difference that ala catalyst 16.8 mg (0.05 mmol) Pd01 ₂ (py) ₂ and 0.14 g of iron heptamolybdate Fe ₂ MOyO ₂ *

- 13 -

were used. 55 % Result: 0 % DHT sales 22 % TDI-A us bag 7 to 47 monoisocyanates AusführunRsbeispiele

In glass inserts of appropriate size were 0.411 g (3 ramol) p-Hitrotoluol (p-NT) 2.6 go ~ DCB, palladium on BaSO ^ support (Pd content 5 / O or a Pa 11a diumv er bond together with various inventive Iron complexes were added in such amounts that the examples were carried out with the following molar ratios: / Pd7: / Je ? : β- ^ iJ = 1: 10: 500 and £ Pd7: £ Fe7: / 5-HTT "= 1: 20: 1000 The glass inserts were used in stainless steel autoclaves, the reaction chamber volumes of which were 25 ml.

Embodiments 7 to 47 were carried out analogously to Examples 3 and 4 with the difference that the reaction temperature was lowered slightly, but the reaction time was increased to 4 hours. The outlet pressure was in any case 250 at. Details can be found in Table 1.

Exemplary embodiments 48 to 53

Some of the embodiments 7 to 22 were repeated as described with the difference that technical Koh-. According to the invention, the reactions also take place under isocyanate formation, however, this comparison demonstrates that the required yields and the selectivity are only achieved with hydrogen-free carbon monoxide. The reaction time was 3 hours, the temperature 215 ⁰ G and the outlet pressure 170 ate details are shown in Table 2 *

- '14

  ; ''; '', \ .. ·. · - 14 -

Exercise Examples 54-60

Some of Embodiments 7 to 17 were repeated in the same manner as described above, except that a minimum catalyst concentration was employed. Thus, for each example, 2.5 'ml' of a solution containing 6 * ΙΟ "** m was added ( Bu.I) ₂ PdpClg and 1.2 m of p-UT in o-DGB was used The iron complex was added so that with a molar ratio of £ Pd7: / JqJ " : / J-IiT / = 1: 100 : 10,000 was worked. Details can be found in table 3.

Exemplary clock u ng, sbeispiele 61 to 64

Embodiment 7 was repeated as described except that no palladium or a palladium compound, but rhodium (I) carbonyl chloride / IlhClCCO) ₂ J ^ p in the presence of 20 mg (PyH) -Fe ₂ CIg was used as a catalyst. Details are given in Table 4.

Execution example 65 to 81

The embodiments 7 to 47 were repeated in the manner described with the difference that instead of the iron complexes used there are each 27 mg (Bu ₄ U) PeCl. and an aromatic nitrogen-containing heterocyclic compound (base) in the presence of the palladium component. The reaction time was 4 hours, the temperature 235 ° C, details are shown in Table 5.

- 15

Table 1: Implementation Examples 7 to 47 (Reaction of p-Kitrοtoluol to p-tolyl isocyanate)

Kr ·: iron complex

Pd component temperature Reacting pressure / srt /

Yield ^ '

mg

It

it is with it

Il M It ti Il

η ti

mg (pyH) ₂ Pe ₂ Cl ₈ (py) ₂

Il

It It It

It Il M ti

2.8 1.4

13.0 6.5 1.0 1.0 2.0 2.0 1.0 1.7 2.8 1.4

13.0 6.5 1.0 0.5

mg

"T * ~ Cm V /

mg

mg Pd / BaSO.

mg "

mg PdCl ₂

mg ^M

mg PdCl ₂ (py) ₂

mg

mg Pd (dba) ₂ ¹ /

mg (Bu ₄ K) ₂ Pd ₂ Cl ₆

mg "

mg Pd / BaSO ₄ .

mg

mg PdCl ₂

mg 236 236 235 235 236 233 234 234 220 235

 236 233 235 235 234

340 340 305 340 330 335 310 310 315 330 340 335 335 340 330

62

54 56 48 92

83 61 46 56 82 74 60

47 93 83

60

52 48

47 63 54 59

46

49 69 68 57 45 71 70

dba = dibenzylideneacetone

Continuation Table 1

Ex. iron complex mg (PyH) ₂ Fe ₂ Cl ₈ (Py) ₂ Pd component temperature ßeaktions- p-NT P-TI ^ Kr · :. 21 Il 2.0 mg PdCl ₂ (py) ₂ druok at £, 7 ψ yield / l7 22 Il η 1.0 mg " 235 305 74 68 23 H mg (Isoquinine) FeCl ₄ ^i; 1.7 mg Pd (dba) ₂ 234 320 62 61 24 20 * It 2.8 mg (Bu ₄ IO ₂ Pd ₂ Cl ₆ 220 315 54 45 25 It ti 1.4 mg " 235 305 75 60 26 ii η 13.0 mgPd / BaSO ₄ 235 305 50 46 27 Il M 6.5 mg " 235 305 52 41 28 It ft 2.6 mg PdOlgClsoohin, 340 56 38 29 It mg (Chin.H) PeCl ,, ³ ) 1.3 mg » ^2} 235 335th 53 41 30 20 t Il 2.8 mg (Bu ₄ H) ₂ Pd ₂ Cl ₆ 235 340 40 38 31 Il It 13.0 mg Pd / BaSO ₄ 235 305 26 23 32 M mg (Acrid.H) ^ Pěčín 2.6 mg PdCl ₂ (Chin.) ⁴ ^ 235 330 39 28 33 35 & m * M 2.8 mg (Bu ₄ U) ₂ Pd ₂ Cl ₆ 235 330 21 20 34 It ti 1.4 mg " 235 340 96 57 35 η II- 13.0 mg PdZBaSO ₄ 235 343 48 45 36 Il 6.5 mg " 234 305 32 30 37 235 330 32 30

1) isoquinine .H = isoquinolinium, 4) Chin. = Quinoline

3) Chin.H = quinolinium;

Position Table 1:

Ex., Temperature Reactions p * -HT-

Kr .: iron complex Pd component Z. ^ 27 pressure / atj conversion / 17 yield / ^ /

38 35 mg (ACrId ^) ₂ PeCl ₅ 1.0 mg PdCl ₂ 235 340 75 50

39 21 mg (PyH) ₂ PeCl ₄ 1.0 mg »235 - 308 76 64

40 »11 0.5 mg" 233 310 65 57

41 "" 13.0 mg Pd / BaSO ₄ 235 335 50 48

42 »» 6.5 mg »235 340 46 44

43 ^{tt n} 2.0 mg PdCl ₂ (py) ₂ 235 335 94 75

44 " ^w 1.0mg η '* 235 340 86 59

45 27 mg PeCl ₂ (Py) ₄ 1.4 mg (Bu ₄ K) ₂ Pd ₂ Cl ₆ 234 315 53 51

46 »» · 0.5 mg PdCl ₂ 235 330 61 49

47 ⁿ "1.0 mg PdCl ₂ (py) ₂ 234 310 42 40

Table 2t Embodiments 48 to 53 (reaction with technical CO with 0.37 vol.% H ₃ )

For example, reaction p-KT-p-TI

Kr .: iron complex Pd-component pressure / a'tj turnover / ^ 7 AubevAe / W

48 20 mg (PyH) ₃ Pe ₂ Cl ₉ 2.8 mg (Bu ₄ K) ₂ Pd ₂ Cl ₆ 220 35, 8

49 »w w 13.0 mg Pd / BaSO ₄ 210 28 10

50 »» 2.0 mg PdCl ₂ (py) ₂ 215 41 7

51 mg (pyH) ₂ Pe ₂ Cl ₈ (py) ₂ 2.8 mg (Bu ₄ K) ₂ Pd ₂ Cl ₆ 220 25 2

52 "» 13 ₉ 0 mg Pd / BaSO / 210 22 2

53 "" 2.0 mg PdCl ₂ (py) ₂ 215 60 trace

  «18 -

CtJ CtJ

CO • ri

CQ • ri

P.

CJ

approx. 0

la

• ri φ

ca β ο • ri

ca φ

I approx

CJ

0) Hl

O JW

·· e φ P " ca ca • ri φ H 0) '' C CO

52-

co

ν-

ο W ο σ \

OJ OJ <Μ

• sä · O O τ- in τ-r-CVI OJ OJ CM OJ

O οο in σ «χ»

cn (Λ ίΛ W LTi ^ r ^ OJ OJ OJ CM OJ OJ OJ

in

m oy

o o

(Λ CO

ο in ο o

(Λ Π (Λ (Λ

O O O O O O

O ιη <τ \ in ¹ ^ t- ιτν tr »

OJ OJ OJ OJ OJ OJ

«Φ« si · νο «si-« Φ '

OJ

O CJ

to a.

hl

O OJ

¹ R

W)

"* IA VD N CX) -CTi-O

! A 1Λ ΙΓι IA ΙΓι 1Λ VD

CQ

§ • Η

co

Il

P ₁

.Ϊ4 O

ω fco

.CQ

CJ

CTi r-1 O OJ Φ

CD Ci)

CQ • Η Xl

CM

OO "

<H CQ Xi

Hi © Xi

OJ

S ¹

VD VD VD "Φ OJ τ- τ- T-

VO VD VO

Oi τ- τ-

in + in ο

(Λ C ^ (Λ (Λ OJ OJ OJ CM

O O O ιη π- \ cn ο «Φ« Λ ΟΛ OJ τ-

Ο O O

in in ο

OJ OJ τ- τ-

OJ VO VD VD

τ- OJ ίΛ «Φ VO VD VD VO

Table 5: Exemplary embodiments 65 to 81 (reaction in the presence of (Bu ₄ K) PeCl ₄ ) Ex. Base. ^m Baee ^ ⁷ Pd component p, a _ i> r

p-UT-p-TI

Sales / 17 people / 17

65  pyridine 12 66 Il 39 67 Il 52 68 It 82 69 isoquinoline 98 70 quinoline 100 71 pyridine 22 72 Iaochinolin 103 73 111 74 pyridine 7 75 H 16 76 η 27 77 M 37 78 » 48 79 It 63 80  ti. 98 81   it- 121

13 a PdZBaSO ₄ it 250 310 23 Il It 250 315 44 η Il It 250 320 47 ti It tt 250 310 53 η ti M 250 310 48 It It tt 250 305 53 4.5 mg (Bu ₄ U) ₂ pd η ₂ C1 ₆ 15O 200 58 Il It 250 330 85 tt ti 250 330 94 2 mg PdCl ₂ (py) ₂ 250 330 24 ti 250 330 42 Il 250 330 55 η 250 325 63 η 250 335 70 η 250 335 80 It 250 335 80 η 250 330 89

42 44 48

39 50

65 65 24 41 54 61 66 76 76 73

Claims (4)

1 · A process for the preparation of aromatic isocyanates, characterized in that in a semi-continuous process, aromatic nitro compounds are reacted with carbon monoxide under substantially water and hydrogen-free conditions at elevated temperatures and elevated pressure in the presence of a catalyst system while maintaining certain molar ratios, with or without a high-boiling Working solvent and the resulting aromatic isocyanate is easily recovered by distillation from the reaction mixture · 2 · Method according to item 1, characterized in that a catalyst system is used which consists of Palladium and / or rhodium and / or at least one compound of these precious metals, - At least one iron halide complex of the general formula ^A k ^Pe l ^X m ^L n ^with X = halogen L = aromatic, nitrogen-containing, heterocyclic See ligand A = organic cation k, l, m, η = integer indices k, n = 0 · I ₁ Bl-O and / or suitable starting substances for forming these iron halide complexes under reaction conditions. 3. The method according to item 1 and 2, characterized in that Eisenhalogenidkoraplexe with chlorine, bromine and iodine, preferably chlorine, are used as halogen · - 21 « 215 4. The process according to items 1 and 2, characterized in that iron halide complexes with pyrrole, imidazol, pyrazole, indole, carbazole, pyridine, pyrazine, pyrimidine, pyrazide, quinoline, isoquinoline, acridine, naphthyridine, phenanthroline, purine, adenine, and derivatives of these Compounds can be used as ligands · 5. The method according to item 1 and 2, characterized in that Eisenhalogenidanionenkomplexe be used with organic cations such as quaternary ammonium ions and / or N-protonated tertiary amines · 6e method according to item 1 and 2, characterized in that suitable starting materials for forming the Eisenhalogenidkomplexe in the stoichiometric ratio or in excess of aromatic, nitrogen-containing heterocyclic compound to the iron halide or ₀ Halogenoferrat used v / earth. 7th method according to item 1 and 2, characterized in that palladium and / or rhodium metallic in finely divided form optionally on inert carriers and / or at least one compound of these noble metals, which reacts under reaction conditions with the iron complexes of the invention to soluble, active catalyst complexes used become· 8. The method according to item 1 and 2, characterized in that reacted as aromatic nitro compounds predominantly mono- and dinitro compounds. 9e method according to item 1 and 8, characterized in that the molar ratio of nitro groups to be reacted (-ΗΌ ^) to the iron complex and the noble metal ip & O ^ J ' ZX§7 · / W Iß. = Pd, Rh7 is selected between 1: 1: 1 and 1000: 10: 1, preferably between 100: 4: 1 and 3000: 30: 1.   -.... '. , '· · - 22 -. 10. The method according to item 1, characterized in that the reaction takes place at temperatures of 160 to 300 ⁰ C ·  11 β method according to item 1, characterized in that a reaction pressure of 20 to 600 at is applied · 12 · Process according to item 1 and 11, characterized in that in a semi-continuous process after distillative removal of the aromatic isocyanates again aromatic litroverbindung is added to the reaction mixture, which is used repeatedly without re-catalyst addition for the reaction.