| abstract |
A precatalyst composition comprising: a) a silica support comprising silica, wherein the silica is present in an amount ranging from about 70 wt % to about 95 wt % based on the total weight of the silica support, b) a chromium-containing compound, wherein the amount of chromium is in the range of about 0.1 wt % to about 5 wt %, based on the amount of silica, c) a titanium-containing compound, wherein the amount of titanium is about 0.1 wt. %, based on the amount of silica In the range of wt % to about 20 wt %, d) a carboxylic acid, wherein the equivalent molar ratio of the titanium-containing compound to the carboxylic acid is in the range of about 1:1 to about 1:10, and e) a molecular formula containing at least one nitrogen atom A nitrogen-containing compound wherein the equivalent molar ratio of titanium-containing compound to nitrogen-containing compound is in the range of about 1:0.5 to about 1:10. |