Optimizing preparative conditions for tungstated zirconia modified with platinum as catalyst for heptane isomerization

Pt/WO3–ZrO2 catalysts were prepared under different conditions to optimize the preparative variables for active and selective catalyst in heptane isomerization. The variables examined were (1) pre-drying temperature of hydrous ZrO2, (2) way of impregnation, (3) pH of impregnating solution of ammonium metatungstate, (4) WO3 loading, (5) calcination temperature, (6) calcination atmosphere, and (7) Pt source. In addition to well-known strong effects of (4) and (5), all the variables affected to some extent the activity and selectivity for heptane isomerization. In particular, type of Pt source exerted substantial influence on the activity of the resulting catalyst, H4PtCl6 performing better than Pt(NH3)4Cl2.