Formic Acid or Formate Derivatives as the In Situ Hydrogen Source in Au-Catalyzed Reduction of para-Chloronitrobenzene

Formic acid and formate derivatives as hydrogen source on the hydrogenation of para-chloronitrobenzene (p-CNB) over supported gold catalysts were investigated. The hydrogenation activity in various formate derivatives followed the order: HCOOH < HCOONa < HCOOK < HCOONH₄, which was in accordance with the decrement of electronegativity of cation species in formate derivatives. Moreover, in the case of HCOONH₄ as hydrogen source, the p-CNB conversion could enhance ten-fold as the hydrogen source of H₂ at 60 ^oC. This promotion effect was also found in other supported Au catalysts. These results provide a general alternative hydrogen source to replace conventional H₂ as reducing agent for fine chemical processes.