Verfahren zur Herstellung von aromatischen Aminen durch Gasphasenhydrierung

摘要

A process is disclosed for producing aromatic amines by catalytic hydrogenation of corresponding aromatic nitro compounds in the gaseous phase on fixed catalysts which contain one or several metals of groups VIIIa, Ib, IIb, IVa, Va, VIa, IVb and Vb of the periodic table of elements (Mendeleev) on a ceramic substrate with a BET surface of less than 40 m<2>/g, at molar ratios from hydrogen to nitro group(s) from 3:1 to 30:1 and at temperatures in the catalytic bed from 180 to 500 DEG C. The process is characterised in that the aromatic nitro compound load of the catalyst is continuously or gradually increased from 0.01-0.5 to 0.7-5.0 kg/l x h, the maximum load being attained within 10 to 1000 hours. This process can be carried out without problems on an industrial scale and ensures a high space-time yield, together with an improved productivity of the catalysts used.