Nitro to amine reductions using aqueous flow catalysis under ambient conditions

A catalyst based on Pd on glass wool (Pd@GW) shows exceptional performance and durability for the reduction of nitrobenzene to aniline at room temperature and ambient pressure in aqueous solutions. The reaction is performed in a flow system and completed with 100% conversion under a variety of flow rates, 2 to 100 mLmin(−1) (normal laboratory fast flow conditions). Sodium borohydride or dihydrogen perform well as reducing agents. Scale-up of the reaction to flows of 100 mLmin(−1) also shows high conversions and robust catalytic performance. Catalyst deactivation can be readily corrected by flowing a NaBH(4) solution. The catalytic system proves to be generally efficient, performing well with a range of nitroaromatic compounds. The shelf life of the catalyst is excellent and its reusability after 6-8 months of storage showed the same performance as for the fresh catalyst.