Control of catalytic hydrogenation of nitro cpds. - by monitoring redox potential

摘要

Optimum yields are obtd. from reactors used for liq.-phase catalytic hydrogenation of organic nitro cpds. (I) by (a) continuously monitoring the concn. of (I) in the reaction mixt. by measuring the redox potential of the mixt. with a p.d.- measuring probe, and (b) adjusting the concn. of (I) and/or the catalyst when the actual potential diverges from a predetermined value. The redox potential is pref. measured relative to the potential of a hydrogen electrode in the same reaction mixt., and the supply of (I) and/or the addn. of fresh catalyst is controlled in response to the divergence of the potential from the predetermined value. The process allows optimum space-time yields to be achieved with min. catalyst consumption.