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US 9,067,864 B2Granted
Process for producing aromatic amines
AssigneeBayer MaterialScience AG
InventorsKnut Sommer, Ido Schwarz, Susanne Buchholz, Franz-Ulrich Von Gehlen, Andre Lago, Karl-Heinz Wilke, Holger Orzesek, Hans-Georg Pirkl, Peter Lehner, Stephan Schubert
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Abstract
Aromatic amines are produced by adiabatic hydrogenation of nitroaromatic compounds in the gas phase on one or more fixed catalysts. The nitroaromatic reactant is passed over the catalyst under pressure and at elevated temperature with hydrogen, water, optionally nitrogen and substantially in the absence of the aromatic amine produced from the nitroaromatic.
Claims10
A process for producing aromatic amines represented by the formula
- in which
- R1 represents hydrogen, a methyl group, an ethyl group or an amino group, and
- R2 represents hydrogen, a methyl group, or an ethyl group comprising hydrogenating a nitroaromatic compound represented by the formula
- in which
- R2 represents hydrogen, a methyl group, or an ethyl group, and
- R3 represents hydrogen, a methyl group, an ethyl group, or a nitro group,
- with hydrogen on a fixed catalyst,
- in which:
- (1) hydrogenation is performed at
- (a) an absolute pressure of from 1 to 50 bar,
- (b) a gas mixture inlet temperature of from 150 to 400° C., and
- (c) a maximum catalyst temperature of 600° C. under adiabatic conditions, and
- (2) a gas mixture comprising:
- (i) from 3 to 150 moles of hydrogen per mole of nitro groups and
- (ii) from 1 to 100 moles of water per mole of nitro groups is passed through the fixed catalyst at the start of hydrogenation, and
- (3) hydrogen which is substantially free from aromatic amine which is separated from the reaction mixture during hydrogenation is returned to the hydrogenation reaction.
13 more elements
Dependencies are inferred from the claim text.