Selectivity Tuning Options in Hydrogenation of m-Chloronitrobenzene to m-Chloroaniline Over Mono- and Bimetallic Supported Pt Catalysts

Supported monometallic (Pt, Ni,) and bimetallic (Ni–Pt) catalysts were prepared for the selective liquid phase hydrogenation of m-chlronitrobenzene to m-chloroaniline (m-CAN). It was found that the use of sodium carbonate as an additive substantially reduced the extent of dehydrohalogenation in the case of monometallic, 1% Pt/C catalyst, to give the highest selectivity of 96% to m-CAN. Ni–Pt bimetallic catalyst although showed almost complete selectivity (>99%) to m-chloroaniline; its activity was several fold lower than that of 1% Pt/C–Na2CO3 system. However, compared with Ni monometallic catalyst, bimetallic Ni–Pt showed higher activity and selectivity due to the presence of electron rich surface metallic Pt stabilized by Ni having lower ionization potential compared with Pt.