Freeze-dried promoted and unpromoted sulfated zirconia and their catalyticpotential

A new synthesis route for sulfated zirconia and iron, manganese, and iron-m anganese promoted sulfated zirconia has been investigated. Zirconium hydrox ide precursors were prepared from hydrogel and hydro-alcogel; freeze-drying as well as oven-drying has been employed. The pure hydroxides, sulfated, a nd metal promoted sulfated zirconia were calcined at 650 degreesC and chara cterised by chemical analysis, XRD, TG/DTG/DTA, nitrogen adsorption, SEM, F TIR pyridine adsorption, and ammonia TPD. The catalytic activity of the sam ples was screened in the double bond isomerisation of 1-butene and the benz oylation of anisole. Significant differences in the textural and acidic properties were found fo r samples prepared either by freeze- or oven-drying. Virtually no differenc e in acidity was observed between sulfated and metal promoted sulfated zirc onia. Freeze-drying, especially the hydro-alcogel synthesis, was found to be a po werful preparation method for promoted and unpromoted sulfated zirconia cat alysts.