Selective Reduction of Chloronitrobenzene to Chloroaniline on Ru/MgF2 Catalysts

The use of magnesium fluoride as a support for ruthenium has enabled to obtain a catalyst of high activity and selectivity for hydrogenation of ortho-chloronitrobenzene (o-CNB) to ortho-chloroaniline (o-CAN) in the liquid-phase at 353 K under 4 MPa of hydrogen pressure. The introduction of water to methanolic medium of the reaction (volume ratio of water to methanol equal to 1:2) has resulted in almost fivefold increase in catalytic activity, while selectivity towards o-CAN remained on the level close to 100%. The nature of ruthenium precursor and catalyst activation conditions appeared to have a clear influence on metallic phase dispersion that was reflected by the activity of Ru/MgF2 catalysts. The catalysts of poorer dispersion were more active in o-CNB hydrogenation, however, their selectivity to o-CAN was slight lower.