Methods of preparing a catalyst

A polymerization catalyst prepared by

• (a) forming a hydrogel comprising (i) water and (ii) an agglomeration of titanium-silica-chromium nanoparticle, wherein each titanium-silica-chromium nanoparticle agglomerate is an agglomeration of titanium-silica-chromium nanoparticles, the agglomerates having an average titanium penetration depth designated x with a coefficient of variation for the average titanium penetration depth of less than about 1.0 wherein a silica content of the hydrogel is of from about 18 wt. % to about 35 wt. % based on a total weight of the hydrogel;
• wherein the titanium content is from about 0.15 wt. % to about 1.5 wt. % based on the total weight of the hydrogel;
• wherein the chromium content is from about 0.15 wt. % to about 1.2 wt. % based on the total weight of the hydrogel and wherein the pH of the solution at gelation is from about 2 to about 5;
• (b) alkaline aging the hydrogel to form an aged hydrogel;
• (c) washing the aged hydrogel to form a washed hydrogel;
• (d) vacuum oven-drying the washed hydrogel to form a precatalyst;
• and
• (e) calcining the precatalyst to form the polymerization catalyst having a pore volume of equal to or greater than about 1.33 mL/g.

A polymerization catalyst prepared by

• (a) forming a hydrogel comprising (i) water and (ii) an agglomeration of titanium-silica-chromium nanoparticle, wherein each titanium-silica-chromium nanoparticle agglomerate is an agglomeration of titanium-silica-chromium nanoparticles, the agglomerates having an average titanium penetration depth designated x with a coefficient of variation for the average titanium penetration depth of less than about 1.0 wherein a silica content of the hydrogel is from about 18 wt. % to about 35 wt. % based on a total weight of the hydrogel;
• wherein the titanium content is from about 0.15 wt. % to about 1.5 wt. % based on the total weight of the hydrogel;
• wherein the chromium content is from about 0.15 wt. % to about 1.2 wt. % based on the total weight of the hydrogel and wherein the pH of the solution at gelation is from about 2 to about 5;
• (b) alkaline aging the hydrogel to form an aged hydrogel;
• (c) washing the aged hydrogel to form a washed hydrogel;
• (d) drying the washed hydrogel by azeotropic distillation to form a precatalyst;
• and
• (e) calcining the precatalyst to form the polymerization catalyst having a pore volume of equal to or greater than about 2.87 mL/g.