Zirconia-titania-silica tergels and their use as catalyst supports
AssigneeEnron Chemical Company
InventorsRobert A. Dombro, William Kirch
Life of this patent
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Abstract
A method of preparing a high pore volume, high surface area zirconia-titania-silica tergel useful as an olefin polymerization or copolymerization catalyst support comprises the steps of coprecipitating hydrous zirconia, hydrous titania and hydrous silica, aging and washing the resulting hydrotergel, removing water from the washed hydrotergel and optionally calcining the resulting xerotergel. Resins with predetermined properties such as high melt index, broad molecular weight distribution, high weight swell, etc. can be produced from catalysts of the chromium or Ziegler type based on these supports.
Claims54
A method of preparing zirconia-titania-silica tergels comprising the steps of:
- (a) mixing a zirconium compound of the formula M.sub.4 Zr(C.sub.2 O.sub.4).nH.sub.2 O and a titanium compound of the formula M.sub.2 TiO(C.sub.2 O.sub.4).sub.2.nH.sub.2 O, where M is an alkali metal or ammonium ion and n equals 0 to 10, with a silicon compound of the formula A.sub.2 SiO.sub.3, where A is an alkali metal ion, in an aqueous solution at a pH sufficiently high to avoid precipitation of a tergel;
- (b) adding an acidic material to said solution to lower the pH thereof sufficiently to result in precipitation of a porous hydrotergel containing silica, titania and zirconia and having a pore volume of at least about 1.5 cc/g, said zirconium, titanium and silicon compounds of (a) being mixed in proportions selected to result in respective independent concentrations of said zirconia and titania of between about 0.1 wt. % and 5 wt. % with respect to said silica;
- (c) aging said hydrotergel of (b);
- (d) washing and said hydrotergel of (c) with an aqueous liquid;
- and
- (e) removing water from the washed hydrotergel of (d) by a method selected to avoid substantial collapse of the pores of said hydrotergel to produce a xerotergel having a pore volume of at least about 1.5 cc/g.
A zirconia-titania-silica tergel prepared by the method comprising the steps of:
- (a) mixing a zirconium compound of the formula M.sub.4 Zr(C.sub.2 O.sub.4).nH.sub.2 O and a titanium compound of the formula M.sub.2 TiO(C.sub.2 O.sub.4).sub.2.nH.sub.2 O, where M is an alkali metal or ammonium ion and n equals 0 to 10, with a silicon compound of the formula A.sub.2 SiO.sub.3, where A is an alkali metal ion, in an aqueous solution at a pH sufficiently high to avoid precipitation of a tergel;
- (b) adding an acidic material to said solution to lower the pH thereof sufficiently to result in precipitation of a porous hydrotergel containing silica, titania and zirconia and having a pore volume of at least about 1.5 cc/g, said zirconium, titanium and silicon compounds of (a) being mixed in proportions selected to result in respective independent concentrations of said zirconia and titania of between about 0.1 wt. % and 5 wt. % with respect to said silica;
- (c) aging said hydrotergel of (b);
- (d) washing said aged hydrotergel of (c) with a aqueous liquid;
- and
- (e) removing water from the resulting washed hydrotergel of (d) by a method selected to avoid substantial collapse of the pores of said hydrotergel to produce a xerotergel having a pore volume of at least about 1.5 cc/g.
An olefin polymerization or copolymerization catalyst prepared by the method comprising the steps of:
- (a) mixing a zirconium compound of the formula M.sub.4 Zr(C.sub.2 O.sub.4).nH.sub.2 O and a titanium compound of the formula M.sub.2 TiO(C.sub.2 O.sub.4).sub.2.nH.sub.2 O, where M is an alkali metal or ammonium ion and n equals 0 to 10, with a silicon compound of the formula A.sub.2 SiO.sub.3, where A is an alkali metal ion, in an aqueous solution at a pH sufficiently high to avoid precipitation of a tergel;
- (b) adding an acidic material to said solution to lower the pH thereof sufficiently to result in precipitation of a porous hydrotergel containing silica, titania and zirconia and having a pore volume of at least about 1.5 cc/g, said zirconium, titanium and silicon compounds of (a) being mixed in proportions selected to result in respective independent concentrations of said zirconia and titania of between about 0.1 wt. % and 5 wt. % with respect to said silica;
- (c) aging said hydrotergel of (b);
- (d) washing said aged hydrotergel of (c) with an aqueous liquid;
- (e) removing water from the washed hydrotergel of (d) by a method selected to avoid substantial collapse of the pores of said hydrotergel to produce a xerotergel having a pore volume of at least about 1.5 cc/g;
- (f) calcining said xerotergel of (e);
- (g) introducing a catalytically active compound onto said calcined xerotergel of (f);
- and,
- (h) activating to produce an active polymerization or copolymerization catalyst.
Dependencies are inferred from the claim text.