Patent ID: 6495733
Filing Date: 2002-12-17
Classification: B01J,C07C

Abstract:
A superacid catalyst having a porosity ranging from 0.1 to 0.30 cm3/g, consisting of at least 70% of pores with a diameter ranging from 1 to 4 nm, comprising zirconium oxide consisting of crystallites of pure tetragonal phase with dimension of less than 300 Angstroms, the zirconium oxide surface having sulfate groups thereon in a quantity corresponding to the total coverage of the surface of zirconium oxide by a monolayer of said sulfate groups, obtained by means or a process which comprises:(a) hydrolyzing a hydrolyzable derivative of zirconium in a basic medium in the presence of a tetra-alkylammonium hydroxide (TAA), sulfuric acid and acetylacetone (AcAc); (b) drying the product of step (a) and calcining the dried material at a temperature ranging from 250 to 650Â° C.; (c) optionally treating the product resulting from step (b) with an aqueous solution of a compound of a noble metal, and drying and calcining the treated product.