Bayer Aktiengesellschaft

Joachim Schneider

Helmut Waldmann

Zoltan Kricsfalussy

Harald Medem

Gunter Stammann

Catalysts for the gas-phase reduction of aromatic nitro compounds to aromatic amines are regenerated by treatment of the catalyst, at elevated temperature, with a gas mixture which contains oxygen, inorganic and/or organic amines and/or nitrogen oxides and, where appropiate, steam.

Process for the regeneration of catalysts for the gas-phase reduction of

An improvement in a process for the alkylation of an aromatic amine by contacting an aromatic amine with an alcohol in the presence of phosphoric acid, the improvement residing in including in the phosphoric acid an aliphatic amine containing at least one aliphatic radical having more then 3 carbon atoms, a phosphoric acid salt of said aliphatic amine or a quaternary ammonium salt of said aliphatic amine.

N-akylation of aromatic amines in the presence of an aliphatic amino

N-alkylated aromatic amines are prepared by heating an aromatic amine together with a lower aliphatic alcohol in the presence of from 0.01 to 1.0 mol of phosphoric acid per nitrogen equivalent at a temperature in the range of from 150.degree.-280.degree.C. Thereafter, the liquid phases that form are separated to isolate the N-alkylated aromatic amine.

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Krefeld, Germany

Joachim Schneider