Preparation of essentially alkali-free titanium zeolites
AssigneeBASF SE
InventorsUlrich Mueller, Wolfgang Hoelderich
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Abstract
A process for preparing essentially alkali-free titanium silicate crystals having a zeolite structure, comprises reacting an SiO.sub.2 -containing mixture of water, a tetraalkylammonium compound, a titanium component and ammonia in the absence of a metal hydroxide or salt under hydrothermal conditions in a molar ratio of ammonia/tetraalkylammonium of from 3:1 to 200:1.
Claims8
A process for the preparation of essentially alkali-free and amine-free titanium zeolite crystals which have an elongate platelet shape and a diffractogram corresponding to the orthorhombic MFI structure with a characteristic band in the IR spectrum of from 950 to 960 cm.sup.-1, which comprises:
- reacting for crystallization under hydrothermal conditions an aqueous reaction mixture consisting of water, ammonia, SiO.sub.2, a tetraalkylammonium halide selected from the group consisting of tetrapropylammonium chloride and tetrapropylammonium bromide, and a peroxotitanate compound dissolved in water or alcohol, in a molar ratio of ammonia/tetraalkylammonium halide of from 3:1 to 200:1 while maintaining a molar ratio of ammonia, used as aqueous solution, to SiO.sub.2 of from 10:1 to 1:1, and in a molar ratio of SiO.sub.2 /TiO.sub.2 of from 10:1 to 1500:1;
- and
- subsequently subjecting the product of said hydrothermal crystallization to a heat treatment at from 350.degree. C. to 600.degree. C.
Dependencies are inferred from the claim text.