METHOD FOR PREPARING ANILINE AND CATALYST FOR PREPARING ANILINE AND OTHER AMINES Russian patent published in 2003 - IPC

FIELD: organic chemistry, chemical technology, catalysts. SUBSTANCE: invention relates to the improved method for preparing aniline and new catalyst for preparing aniline and other amines. Aniline is a raw in production of dyes, antioxidants, stabilizing agents for rubber, addition agents to fuels and oils, pharmaceutical preparations and other products of organic synthesis. Method involves steam-phase hydrogenation of nitrobenzene at enhanced temperature on oxide copper-zinc-aluminum catalyst of the following composition, wt.-%: CuO, 52-63; ZnO, 24-27; Al₂O₃, 5-11; CaO, 1.1- 6.1; SiO, 1.8-2.2; P₂O₅, 1.8-2.2; graphite, the balance. Process is carried out at temperature 180-350 C and the end product is isolated from catalysate by rectification. Usually, hydrogenation is carried out by feeding nitrobenzene as measured 0.4-0.7 g/h/1 g of catalyst in the mole ratio hydrogen : nitrobenzene in the ranges = (3.5-4.5):1. Hydrogen can be diluted with nitrogen in the volume ratio = 3:2. Invention relates also to catalyst of composition indicated above. Method provides preparing aniline with yield 99.8% and conversion of nitrobenzene above 99.99% for 850 h of continuous working on the new catalyst. New using catalyst doesn't require expensive promoting additions, working period of catalyst is prolonged without reduction of its activity (820 h, not less) and after regeneration catalyst recovers its initial activity. Catalyst can be used in reduction of other nitro-compounds in preparing, for example, o-toluidine, cyclohexylamine. EFFECT: improved preparing method, enhanced yield and conversion, valuable properties of catalyst. 5 cl, 9 ex