METHOD OF PREPARING ZIRCONIA-SILICA XEROGELS, THE XEROGELS, AND XEROGEL CATALYSTS

摘要

A method of preparing large pore volume zirconia-silica catalyst supports, the resulting supports and a method of polymerizing olefins comprising contacting an olefin or mixture of olefins with a catalyst prepared with these supports. The supports are prepared by reacting a zirconium compound of the formula M4Zr(C2O4)4?nH2O , where M is an alkali metal or ammonium ion and n equals 0 to 10, with a silicon compound of the type A2SiO3 , where A is an alkali metal, in an aqueous solution at a pH equal to at least 11, then adding an acidic solution to a pH of about 5-9 to produce a hydrocogel. The hydrocogel is then aged and washed free of soluble by-products first with water, then with aqueous ammonium nitrate and again with water. The water is removed from the washed hydrocogel by azeotropic distillation or by washing with a water miscible solvent and then calcining the resulting xerocogel.