Publications Details
Zirconium-titanium phosphate acid catalysts synthesized by sol gel techniques
Recently a large effort has been put into identifying solid acid materials, particularly sulfated zirconia and other sulfated metal oxides, that can be used to replace environmentally hazardous liquid acids in industrial processes. We are studying a group of mixed metal phosphates, some of which have also been sulfated, for their catalytic and morphological characteristics. Zirconium and titanium are the metals used in this study and the catalysts are synthesized from alkoxide starting materials with H3PO4, H2O, and sometimes H2SO4 as gelling agents. The measurement of acidity was achieved by using the isomerization of an olefin as a model reaction. The phosphate stabilized the mixed metal sulfates, preventing them from calcining to oxides boosting their initial catalytic activity. The addition of sulfate prevented the formation of the catalytically inactive mixed metal pyrophosphates when calcined at high temperatures (>773 K). 1998 Elsevier Science B.V.