Modification of metal complex on hydrogenation of o-chloronitrobenzene over polymer-stabilized platinum colloidal clusters

The effect of metal complex on hydrogenation of o-chloronitrobenzene (CNB) over poly-vinylpyrrolidone-stabilized platinum clusters (PVP-PO has been st udied in methanol at 303 K and atmospheric pressure. The addition of metal complexes to the catalytic system can considerably modulate both the activi ty and the selectivity of the catalyst. A low activity (0.41 mol H-2/mol Pt s) and low selectivity (42.6%) were obtained when the neat PVP-Pt colloida l clusters were used as a catalyst. Upon the addition of the complexes Ni(A cAc)(2) and Na[Co(AcAc)(3)], the better selectivity to o-chloroaniline to-C AN) were promoted to 76.2% and 76.5%, and the higher activities (0.72 mol H -2/mol Pt s and 0.83 mol H-2/mol Pt s) were obtained, respectively. On the other hand, when the complex Ni(en)(3)Cl-2 was introduced as a modifier, th e highest selectivity to o-CAN (94.0%) was achieved, though the activity wa s lowered to 0.16 mol H-2/mol Pt s. (C) 1999 Elsevier Science B.V. All righ ts reserved.