A highly active and stable platinum-modified sulfated zirconia catalyst -: 1.: Preparation and activity for n-pentane isomerization

A procedure to prepare Pt-promoted sulfated zirconia (SZ) catalysts which results in highly active and stable catalyst for n-pentane isomerization at atmospheric conditions, is described. High temperature calcination of SZ prior to Pt addition leads to elimination of loosely-bound sulfur species from the zirconia surface. Reducing the catalyst after Pt addition results in further increase in apparent activity. Upon repeated regenerations, an increase of up to 60% in conversion with iso-pentane selectivity of over 80% is observed. It is proposed that regenerative oxidation/reduction cycles lead to a restructuring of the acid and metal sites which facilitates hydrogen migration and helps to arrest deactivation. (C) 2004 Elsevier B.V All rights reserved.