Impregnation of the Outer Layer of Active Alumina Pellets with a Ruthenium Salt

摘要

A request was received to investigate the possibility of manufacturing research quantities of active alumina-supported ruthenium catalysts; the metal being deposited only on the outer zone of the catalyst pellets so as to obviate diffusive intrusions. A technique is described whereby the outer layer (approximately 0,2 mm) of active alumina pellets is impregnated by immersion in a ruthenium chloride solution. The depth of penetration into wet pellets is controlled by the time of immersion (penetration being roughly a linear function of t 1/2) and to a lesser extent by the concentration of the solution. Pellets containing about 1,7% of ruthenium in the surface layer can be prepared through immersion in a 10% solution of RuCl3.3H2O for just longer than one minute. Due to adsorption onto the alumina surface, the ruthenium concentration in the impregnated zone decreases towards the inner edge of the zone.