CS274021B1 - Method of aromatic nitro-compounds' reducing carbonylation - Google Patents

Abstract

Aromatic nitro-compounds (nitrobenzene, dinitrobenzene, dinitrotoluene) are carbonylated with carbon monooxide, which can contain hydrogen or inert gasses, in the presence of organic hydroxy compounds (aliphatic alcohols C1 to C5), at 80 to 220 degrees C and pressure of 1 to 30 MPa and with catalytic action of metals and compounds of platinum (Pd). Furthermore, at least one halide from the group I.b, II.b, V.a, V.b, VI.b, VII. and iron and/or at least one tertiary amine (pyridine), whereas oxygen (O, O2, O3) and/or peroxide (H2O2, tert-butylhydroperoxide, di-tert-butylperoxide) in a total amount of 0.02 to 6 % by weight (1 to 3 % by weight), calculated on the aromatic nitro-compounds, is added to the reaction environment, altogether or in parts.

Description

³ CS 274021 Bl

The invention relates to a process for the reductive carbonylation of aromatic nitro compounds, in particular lithiumtrotoluone, as well as their derivatives with carbon monoxide and organic hydroxyl compounds, in the presence of catalysts and other active activators, thereby forming the corresponding urethanes. mono- to trialkylarylurethanes or alkyl-N-phenylcarbamates to trialkyl-N-phenyltricarbamates.

Monoisocyanates and diisocyanates can be prepared by carbonylating nitro compounds with carbon monoxide at higher temperatures and pressures under the catalytic action of halides VIII. groups of the periodic system together with iron and vanadium oxides and optionally also in the interaction of pyridine bases, the reaction medium being free of water and hydrogen (Macho V. et al., Chemical Industry 25/50, 140 (1975); Schwetlick K. and ii GDR Pat. 123 807). That is, water and hydrogen react in situ with the isocyanates formed (Beeenyli G. et al. React. Kinet. Catal. Lett. 24, 293 (1984)). Thus, in the presence of even small amounts of hydrogen in carbon monoxide in the carbonylation of nitrobenzene under the catalytic action of palladium chloride, not phenyl phenyl isocyanate but diphenylurea is obtained. Thus, despite the intensive study of the carbonylation of nitroaromatics to aromatic isocyanates from r. 1964, selectivity problems persist, and ultimately low isocyanate yields.

However, the purity requirements of raw materials, both in terms of the presence of hydrogen and water, may be much lower if the isocyanates are led through a reductive carbonylation of nitro compounds, e.g. nitrobenzene with carbon monoxide in the presence of an alcohol such as methanol, ethanol, etc. The resulting alkylphenylurethane (alkyl-N-phenylcarbamate) is then cleaved thermally or thermocatalytically to the phenyl isocyanate to regenerate the alcohol. These reactions can be illustrated as follows:

- 200 c ^ O ^ -JHC00R + 2CO ₂ ', 0> COOIi c 0 + ROH

The excess alcohol present reacts in situ with the phenyl isocyanate formed to the corresponding alkylphenylurethane (alkyl N-phenylcarbamate) and thus effectively protects it from other subsequent and possibly simultaneous reactions. Said reductive N-carbonylation of nitroarenes is generally catalysed by platinum group metals of the periodic system and their compounds, with the assistance of metal halides of groups Ib, II.b, Va, Vb, VI.a, VI.b, VII.a and iron, as well as t-amines (Japanese Pat. 57 (82), 200, 349 (1982); CA 99, 5375 (1983)).

Thus, the reductive N-carbonylation of nitroarenes to carbamates is catalyzed by platinum complex Cl, Pt (PPh 3) 2 with tin tetrachloride or ferric chloride, optionally titanium tetrachloride and triethylamine in ethanol at 180 ° C and 6 MPa. The yields of ethyl N-phenylcarbamate are 38-87% (Watanabe Y. et al., Bul. Chem. Soc. Japan 56, 3343 (1983)). Virtually all catalytic systems active in the synthesis of isocyanates from nitro compounds and carbon monoxide are also active in the synthesis of carbamates. Thus, when used as a catalyst (Rh (CO) ₂ Cl) 2 with ferric chloride and media in a phenol environment, phenyl-N-phenylcarbamate is obtained with a yield of 28%, methyl-N-phenylcarbamate in methanol and 1,3-dinitrobenzene in methanol dimethyl 1,3-phenylenedicarbamate (Manov-Juvensklj VI, Nefedov Β K .: Uspechi chim. 50, 889 (1981)). Again, nitrobenzene is carbonylated to ethyl N-phenylcarbainate in ethanol in the presence of the PdCl 3 -pyridine-FeCl 3 catalyst system at a carbon monoxide pressure of 2-12 MPa and at a temperature of 180-220 ° C. As the palladium chloride content increases, the reaction rate increases as expected, but practically does not occur without ferric chloride, and the palladium chloride is reduced to palladium black (Nijazov, Nefedov: Doc. USSR 246, 118 (1979); Jan B, Ju., Nefedov Β. K .: Sinteza on the warp of the oksid ugleroda,

130. izdatePstvo Khimiya, Moscow (1987)). However, such a process requires a relatively high level

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CS 274021 B1 content of the catalyst system, in particular both palladium and ferric salts.

However, the positive effect of oxygen has been unequivocally proved and used in the synthesis of alkylphenylurethanes, resp. alkyl-N-phenylcarbamates from aniline instead of nitrobenzene, carbon monoxide and alcohols. Thus, urethane compounds are prepared from primary or secondary amines or ureas with carbon monoxide, alcohol and oxygen at 80-300C and 0.1-50 MPa using a platinum group metal catalyst and a halogen-containing compound such as e.g. Ethyl N-phenyl carbamate is formed from aniline, ethanol, carbon monoxide and oxygen at 160 and 8.6 MPa on palladium black or rhodium on activated carbon together with cesium iodide for 1 h with a yield of 85% (Pukoaka Sh. et al .: European Patent 83,096 (1983), J. Chem. Soc., Chem. Commun., 1984, p. 399, J. Org. Chem., 49, 1458 (1984), Japanese Pat 58 (83), 157,753. (1983); CA 100, 51299 (1984); Japanese Pat 58 (83), 164,565 (1983); CA 100,513-02; Japanese Pat 59 (84) 106,452 (1984); CA 102 5910 (1985). Similar results are obtained with other oxygen-containing aromatic amines, alcohols and carbon monoxide, in a protonic acid environment, with the catalytic action of honey and at least one metal of the palladium, rhodium, ruthenium, iridium and cobalt catalysts. (European Pat.

173,457 (1986)) or palladium (II) chloride together with ferric oxychloride (German Pat. No. 2,908,251). Even diphenylmethane diisocyanates (MDI) can be produced from aniline, carbon monoxide, ethanol and oxygen via the intermediate ethyl N-phenylcarbamate under the catalytic action of palladium and iodides, or generally alkali metal halides, followed by condensation with formaldehyde in an acidic medium (diluted). to diethyl-4,4'-diphenylmethanedicarbamate and to a small extent to diethyl-2,4'-diphenylmethanedicarbamate and thermal decomposition at 100-350 ° C to MDI (mainly 4,4'-diphenylmethane diisocyanate) and ethanol (Chemtech 14

670 (1984); Chono et al .; C. Λ. 100, 139, 654 (1984). These processes, however, require aromatic amines, such as aniline, 1-methyl-2,4-diamine-benzene, as starting nitrogen raw materials,

4,4'-diamino-diphonyl-methane and the like Dimethyl-2,4-toluene dicarbamate as a precursor of 2,4-toluene diisocyanate may be prepared from a drawbar of 2,4-dinitrotoluene, carbon monoxide and methanol under the catalytic effect of palladium on alumina or activated carbon and ferric chloride, but low yields are obtained ( French Pat. 2,008,365).

However, according to the present invention, there is provided a method for the reductive carbonylation of aromatic nitro compounds, in particular nitrobenzene, dinitrotoluene and derivatives thereof, with carbon monoxide and an organic hydroxy compound, preferably an aliphatic alcohol C ^-C ^ at a temperature of 80 to 220 ° C and a pressure of 1 to 30 MPa at the catalytic action of a system formed of a metal or metals of the platinum group and / or compounds thereof, preferably palladium compounds and at least one halide of Group Ib, II.b, Va, Vb, VI.a, VI.b, VII.a and iron; and / or at least one tertiary amine, preferably pyridine, is carried out in such a way that oxygen and / or peroxide are added in one or more portions to the reaction medium in a total amount of 0.02 to 6% by weight, preferably 1 to 3% by weight, calculated as aromatic nitro compound or aromatic nitro compound.

In particular, the reductive carbonylation of the aromatic nitro compounds of the present invention yields mainly alkyl-N-phenylcarbamates and derivatives thereof, mainly useful as pesticides or pesticide intermediates, and in particular intermediates for the production of arylisocyanates to aryltriisocyanates.

The advantage of the process according to the invention is the higher reaction rate and the selectivity of the reductive carbonylation in the presence of controlled amounts of oxygen and resp. lower consumption of noble metals or their compounds as components of the catalytic system. A further advantage is the possibility of using a mixture thereof with inert gases and hydrogen instead of pure carbon monoxide, whereby hydrogen admixtures can be used in the reaction and thus reduce the carbon monoxide consumption.

The components of the catalytic system for the reductive carbonylation of aromatic nitro compounds, the pressure and temperature data of the reaction are well known from the cited sources as well as from other known publications and patents.

CS 274021 Bl

The oxygen supplied to the carbonylation reaction medium may be in the form of atomic, molecular or oligomers of oxygen, mainly ozone, and may be added together with carbon monoxide or separately, e.g. mixed with nitrogen and thus use oxygen as a donor of oxygen. Particularly suitable are ozone impurities in molecular oxygen or air.

The term peroxide in the present invention includes both hydrogen peroxide and sodium peroxide, organic hydroperoxides such as a target. butyl hydroperoxide, ethylbenzene hydroperoxide, cumene hydroperoxide, as well as organic peroxides, in particular more thermally stable, such as di-tert-butyl peroxide, dicumyl peroxide and the like, but useful although dibenzoyl peroxide, diocinyl polyoxide and other commercially available organic peroxides.

It is desirable to regenerate the components of the catalytic system, especially the platinum group metal compounds, most commonly palladium compounds, such as e.g. by known methods (Jap. Pat. 61 (86), 215 362 (25.9.1986) and Japanese Pat. 61 (06), 215 363 (25.9.1986; C. Nos 106, 199 706 and 217). 411 (1987)) or returning at least a substantial portion of the distillation residue of the carbonylation product distillation, which contains, in addition to a small amount of by-products, mainly components of the catalytic system of carbonylation of aromatic nitro-compounds.

The carbonylation of the aromatic nitro compounds according to the invention can be carried out in a continuous, semi-continuous or continuous manner,

Further details of the process as well as the advantages are also evident from the examples.

Example 1

Weigh 15 g of nitrobenzene, 30 g of methanol, 0.9 g of palladium chloride, 2 g of pyridine, 2 g of pyridine hydrochloride, 0.05 g of uranium dioxide, 0.3 g of iron oxide and 0.3 g into a 300 cm ³ rocking autoclave. g of vanadium pentoxide. After the autoclave is closed and the air is removed, carbon monoxide is admixed with an admixture of 0.009% by volume. oxygen and 0.5 vol. hydrogen at a pressure of 13 MPa at room temperature.

Carbonylation is carried out at 170 ° C for 2 hours. Nitrobenzene conversion reached 67% and selectivity to methyl N-phenylcarbamate 90.1% and aniline 8.5%.

In contrast, under otherwise similar conditions, but using carbon monoxide with 1.5 vol. oxygen and 2.1 vol. hydrogen conversion of nitrobenzene reaches 98% and selectivity to methyl N-phenylcarbamate 92.1% and aniline 7.9%.

7 and otherwise similar conditions, but using 60 g of n-butanol instead of 30 g of methanol, the conversion of nitrobenzene reached 88.9 Sa, the selectivity to butyl N-phenylcarbamate was 87.5% and the aniline 9.9%.

Example 2

100 g of nitrobenzene, 200 g of methanol, 1.5 g of anhydrous palladium chloride, 15 g of iron (III) chloride anhydrous and 15 g of pyridine are weighed into a rotating stainless steel autoclave with an electrical resistance winding of 1 dm ³ . After the autoclave is closed, the air is purged with nitrogen containing 0.8% v / v. oxygen. Carbon monoxide with 2.44 vol% admixtures is then passed through. hydrogen, 1,72 S vol. nitrogen and 0,39% vol. oxygen up to 14 MPa / 25 ° C. Thus, the total amount of molecular oxygen present is 0.5% by weight. / Nitrobenzene. Thereafter, the autoclave was heated to 170 ° C for 30 minutes with constant rotation and held for 3 hours. It is then cooled to room temperature, the unconverted carbon monoxide is discharged and the liquid product weighed and analyzed. Nitrobenzene conversion reached 44.9%, selectivity to methylphenylurethane 92.3% and aniline 4.2%.

Example 3

The procedure is analogous to Example 2 except that the autoclave is purged with oxygen instead of nitrogen. In this case, a total of 1.4 wt. molecular (

• CS 274021 B1 4 oxygen / nitrobenzene.

Nitrobenzene conversion reached 64.7%, selectivity to methyl N-phenylcarbamate (methylphenylurethane) 92.4% and aniline 7.6%.

In another experiment already with 2.1 wt. % molecular oxygen and in addition 0.7 wt. added target. butylhydroperoxide calculated on nitrobenzene nitrobenzene conversion reached 89.3%, selectivity to methyl N-phenylcarbamate (methylphenylurethane) 92.6% and aniline 7.4%.

In a third experiment with 2.1 wt. in addition, 1.5 wt. di-t-butyl peroxide. Nitrobenzene conversion is 93.1%, methyl N-phenylcarbamate selectivity is 92.7% and aniline 7.1%.

Example 4

The procedure is similar to that in Example 3, except that 70 g of 2,4-dinitrotoluene is used instead of 100 g of nitrobenzene. The 2,4-dinitrotoluene conversion is 99.7% and the selectivity to dimethyl 2,4-toluenedicarbamate is 86.1%,

Under otherwise similar conditions, but with nitrogen purging the autoclave, without the addition of di-torc. % of butyl hydroperoxide and with carbon monoxide with an admixture of only 0.009% by volume. The oxygen conversion of 2,4-dinitrotoluene reaches 47.9% and the selectivity to dimethyl 2,4-toluenedicarbamate is 46.3%.

Claims (1)

OBJECT OF THE INVENTION A method for the reductive carbonylation of aromatic nitro compounds, in particular nitrobenzene, dinitrotoluene and derivatives thereof, with carbon monoxide and an organic hydroxy compound (s), preferably an aliphatic alcohol to C ^, at a temperature of 80 to 220 ° C and a pressure of 1 to 30 MPa, formed from a metal or metals from the platinum group and / or compounds thereof, preferably palladium compounds and at least one halide from Group Ib, II.b, Va, Vb, VI.b, VII.a and iron and / or at least one tertiary amine, preferably pyridine, characterized in that oxygen and / or peroxide is added in one portion or in portions in a total amount of 0.02 to 6% by weight, preferably 1 to 3%, to the reaction medium; calculated on the aromatic nitro compound or aromatic nitro compounds.