| abstract |
A Pd catalyst for the redn. of nitro cpds. has an Al spinel support. The support pref. has a specific surface of 20-120 m2/g. and an av. pore dia. of 200-800 angstroms. the spinel-forming metal is pref. Co, Mg, Li, Ni, or Zn. The catalyst pref. contains 0.1-10, esp. 0.5-5wt.% Pd. It can be used (a) for the redn. of nitro cpds. in the presence of a liquid diluent, pref. recycled amine prodt., by trickling the reaction mixt. over the fixed catalyst at 50-240 degrees C under H2 pressure in a tube reactor, the heat of reation being removed by coolant surrounding the tube; (b) for the gas-phase redn. of mononitro cpds.; or (c) for the reductive alkylation of nitro cpds., by adding an aldehyde or ketone, pref. acetone, during hydrogenation. The catalyst is highly active and allows low reaction temps. to be used. the prodts. can be used, e.g., for the prodn. of isocyanates and plant-protection agents. |