Methods of Preparing a Catalyst

Abstract

A hydrogel comprising water, and a plurality of titanium-silica nanoparticle agglomerates, wherein each titanium-silica nanoparticle agglomerate is an agglomeration of titanium-silica nanoparticles, the agglomerates having an average titanium loading designated x with a coefficient of variation for the average titanium loading of less than about 1.0, wherein a silica content of the hydrogel is of from about 10 wt. % to about 35 wt. % based on a total weight of the hydrogel.

What is claimed is: 
     
         1 . A hydrogel comprising:
 water; and   a plurality of titanium-silica nanoparticle agglomerates, wherein each titanium-silica nanoparticle agglomerate is an agglomeration of titanium-silica nanoparticles, the agglomerates having an average titanium loading designated x with a coefficient of variation for the average titanium loading of less than about 1.0,   wherein a silica content of the hydrogel is of from about 10 wt. % to about 35 wt. % based on a total weight of the hydrogel.   
     
     
         2 . The hydrogel of  claim 1  wherein the titanium-silica nanoparticles have a coefficient of variation of the average titanium penetration depth of from about 0.1 to about 0.9. 
     
     
         3 . The hydrogel of  claim 1  wherein the titanium-silica nanoparticles have an average particle size of from about 4 to about 7 nanometers. 
     
     
         4 . The hydrogel of  claim 3  wherein a coefficient of variation for the average particle size of the titanium-silica nanoparticles is less than about 1. 
     
     
         5 . The hydrogel of  claim 1  having an x value of from about 0.25 wt. % to about 8 wt. % based on the total weight of the hydrogel. 
     
     
         6 . The hydrogel of  claim 1  having an x value of from about 1 titanium atoms/sqnm to less than about 4 titanium atoms/sqnm. The hydrogel of  claim 1  having a mL pore water in the pores of the hydrogel, per g of silica of from about 1.9 cm 3 /g to about 4.6 cm 3 /g. 
     
     
         8 . A xerogel prepared by dehydration of the hydrogel of  claim 1 . 
     
     
         9 . A pre-catalyst prepared by adding a chromium-containing compound to the xerogel of  claim 8 . 
     
     
         10 . A polymerization catalyst prepared by calcining the pre-catalyst of  claim 9 . 
     
     
         11 . The polymerization catalyst of  claim 10  having a macroparticle size distribution of from about 0.1 μm to about 400 μm. 
     
     
         12 . The polymerization catalyst of  claim 10  having a S s :S l  ratio of about 1. 
     
     
         13 . The polymerization catalyst of  claim 10  having a Ti o /Ti c  ratio of about 1. 
     
     
         14 . The pre-catalyst of  claim 9  having a ratio of titanium X-ray photoelectron spectroscopy 2P signal to silicon X-ray photoelectron spectroscopy 2P signal of equal to or less than about 0.04. 
     
     
         15 . The pre-catalyst of  claim 9  having a ratio of titanium X-ray photoelectron spectroscopy 2P signal to silicon X-ray photoelectron spectroscopy 2P signal of equal to or less than about 0.025. 
     
     
         16 . The polymerization catalyst of  claim 10  having a ratio of titanium X-ray photoelectron spectroscopy 2P signal to silicon X-ray photoelectron spectroscopy 2P signal of equal to or less than about 0.025. 
     
     
         17 . The polymerization catalyst of  claim 10  having a ratio of titanium X-ray photoelectron spectroscopy 2P signal to silicon X-ray photoelectron spectroscopy 2P signal of equal to or less than about 0.04. 
     
     
         18 . A polyethylene polymer powder prepared using the polymerization catalyst of  claim 10 . 
     
     
         19 . The polyethylene polymer powder of  claim 18  having a melt index ranging from about 0.01 g/10 min to about 100 g/10 min. 
     
     
         20 . The polyethylene polymer powder of  claim 18  having a high load melt index ranging from about 1 g/10 min. to about 1000 g/10 min.