Hydrogenation of o-chloronitrobenzene to o-chloroaniline over Pd/C in supercritical carbon dioxide

Hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) with Pd/C has been investigated in supercritical carbon dioxide (scCO2) at 308 K. The influences of several parameters such as CO2, H2 pressures, Pd metal particle size and reaction time have been discussed. CO2 pressure presented markedly effects on the reaction rate and product selectivity under the reaction conditions used, the selectivity to o-CAN at CO2 pressure from 8 to 13 MPa (supercritical region) was larger than that at CO2 pressure below 6 MPa (subcritical region). Moreover, the larger selectivity to o-CAN was obtained in scCO2 compared with that in ethanol.

Graphical abstractIn the hydrogenation of o-CNB over Pd/C, the presence of scCO2 could improve the yield of o-CAN. The reactive rate and the selectivity to o-CAN depended largely on CO2 pressure. In addition, the larger Pd particle benefited the formation of o-CAN in scCO2.Figure optionsDownload full-size imageDownload as PowerPoint slide