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. The hydrogenation activity on the varied formate derivatives as hydrogen source increased with decrement of electronegativity of cation species in formate derivatives. We provide a general guideline to designate a substituent hydrogen source over supported Au catalysts on the hydrogenation reaction.