Back to results
US 5,474,754 AGranted
Preparation of an aluminosilicotitanate isomorphous with zeolite beta
AssigneeArco Chemical Technology, L.P.
InventorsRobert J. Saxton, John G. Zajacek
Life of this patent
Estimating the term…
Abstract
Aluminosilicotitanates having a framework structure isomorphous with zeolite beta are prepared by heating a solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel which has been impregnated with a quaternary tetraethyl ammonium species. The aluminosilicotitanates, which are useful oxidation catalysts, are obtained in high yield using a minimum quantity of template.
Claims15
A method of making a crystalline aluminosilicotitanate having a framework structure isomorphous to zeolite beta comprising:
- (a) reacting a hydrolyzable silicon compound, a hydrolyzable titanium compound, and a hydrolyzable aluminum compound with water under acidic conditions to form a solubilized partial hydrozylate characterized by the absence of precipitated silicon dioxide and titanium dioxide;
- (b) contacting the solubilized partial hydrozylate with an amount of a quaternary tetraethyl ammonium species effective to catalyze further hydrolysis to form a solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel;
- (c) contacting the solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel with a solution of the quaternary tetraethyl ammonium species in a solvent to form an impregnated cogel, wherein the total amount of quaternary tetraethyl ammonium species in steps (b) and (c) is within 50% of the amount needed to occupy the pore volume of the solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel and the amount of solvent is sufficient to dissolve the quaternary tetraethyl ammonium species without forming a slurry of the impregnated cogel in said solvent;
- and
- (d) heating the impregnated cogel at a temperature of from 120.degree. C. to 160.degree. C. for a time sufficient to form the crystalline aluminosilicotitanate.
2 more elements
A method of making a crystalline aluminosilicotitanate having a framework structure isomorphous to zeolite beta comprising:
- (a) reacting a tetraalkyl orthosilicate, a titanium alkoxide, and an aluminum salt with water under acidic conditions to form a solubilized partial hydrozylate characterized by the absence of precipitated silicon dioxide and titanium dioxide;
- (b) contacting the solubilized partial hydrozylate with an amount of quaternary tetraethyl ammonium species effective to catalyze further hydrolysis to form a solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel;
- (c) contacting the solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel with a solution of the quaternary tetraethyl ammonium species in a solvent to form an impregnated cogel, wherein the total amount of quaternary tetraethyl ammonium species in steps (b) and (c) is within 20% of the amount needed to occupy the pore volume of the solid amorphous SiO.sub.2 --TiO.sub.2 --Al.sub.2 O.sub.3 cogel and the amount of solvent is sufficient to dissolve the quaternary tetraethyl ammonium species without forming a slurry of the impregnated cogel in said solvent;
- (d) heating the impregnated cogel at a temperature of from 130.degree. C. to 140.degree. C. for a time sufficient to form the crystalline aluminosilicotitanate;
- and
- (e) calcining the crystalline aluminosilicotitanate at a temperature greater than 400.degree. C.;
- wherein the amounts of tetraalkyl orthosilicate, titanium alkoxide, aluminum salt, and quaternary tetraethyl ammonium species are selected such that the impregnated cogel has a composition expressed in terms of molar ratios within the following ranges:
- SiO.sub.2 /TiO.sub.2 10-100
- SiO.sub.2 /Al.sub.2 O.sub.3 30-800
- X.sup.- /SiO.sub.2 0.05-0.6
- H.sub.2 O/SiO.sub.2 1-5
- M.sup.+ /SiO.sub.2 <0.5
- TEA.sup.+ /SiO.sub.2 0.05-1.0
- wherein M.sup.+ is an alkali metal cation, TEA.sup.+ is the tetraethyl ammonium cation, and X.sup.- is the counter anion present in the quaternary tetraethyl ammonium species.
11 more elements
Dependencies are inferred from the claim text.