Nitro-aromatic hydrogenation

, by Valérie Meille, Claude De Bellefon, Bruno Fumey, Tuong Van Le Doan, Gauthier Averlant, Petr Stavarek

Catalytic hydrogenation is largely used in pharmaceutical industry, for which the most popular reactor is a batch one. This technology gives mass and/or heat transfer limitations resulting in lower selectivities and reduced production (safety reasons). Continuous production (« batch to continuous processes ») would help intensifying these processes by increasing the selectivity and reducing the reactor volume.

Within IMPULSE European project (started in march 2005), LGPC has proposed to develop structured reactors for a continuous production of hydrogenated product of 1 to 5kg/day. Nitro-aromatic hydrogenation has been selected as the target reaction. Its specificity is linked to its high exothermicity ( 500 kJ.mole-1) and its high reaction rate (example of nitro-benzene). Moreover, nitro compounds that are interesting for pharma industry are not as simple as nitro-benzene and are possibly poorly soluble, easily degraded... The proposed reactor will have to face these different problems.