| http://www.w3.org/ns/prov#value | - (1.1) in a first stage (I) a carrier is prepared from (Ia) a finely divided silica gel which has a particle diameter of from 1 to 1,000, preferably from 5 to 500, in particular from 10 to 200, ??m, a pore volume of from 0.3 to 5.0, in particular from 1.0 to 3.0, cm3 /g and a surface area of from 100 to 1,000, in particular from 200 to 500, m2 /g, is of the formula SiO2 . a Al2 O3, where a is from
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