| 摘要 |
<p>The solid catalyst based on amorphous particulate silica comprising titanium (IV), and showing in ultraviolet reflection spectography an absorption band at about 240 nm, is characterized in that the titanium is present in the catalyst in an amount by weight comprised between 0.1 and 10 % with respect to the weight of the silica, and in that the ratio r of the UV absorption intensity mesured at 240 nm and the absorption intensity mesured at 33nm is at least 3.</p> |
