| 摘要 |
Catalyst of formula (TiO2)n.A12O3 (where n is 0.1 to 40) is prepared in two steps : a) treating a solution of Al cpd. and Ti cpd. with a Ti:Al g. atom ratio 20:1 to 1:20, dissolved in a water-miscible solvent, with an aqs. system (water, NH4OH or aqs. organic solvent) in order to precipitate Ti and A1 together as a mixture of hydroxides and oxides ; and b) heating the precipitate at raised temp. in vacuo or in the presence of H2, N2, air, O2, A, CO2, co, Ne, He or an alkali or alkaline earth metal of atomic no. 3 to 56 inclusive. High catalyst activity and polymerisation velocities. The polymers have high mol. wt. and good mechanical properties. |
