| abstract |
ABSTRACT OF THE DISCLOSURE The present invention relates to a silica-based synthetic material characterized in that it is composed by crystalline silica which has been modified with chemical elements chosen from the group consisting fo Cr, Be, Ti, V, Zn and B which enter into the crystalline lattice of silica as replacing elements for silicon, corresponding to the general formula: 0.0001 - 1 MnOm.SiO2 wherein MnOm is the oxide of one or more of the elements above mentioned, said material having a specific surface area exceeding 150 m2/g and having a porous structure. For effecting such a replacement of silicon in the silica lattice, a silicon compound and a compound of silicon-replacing element are reacted, in solution, and in the presence of a clathrating substance, at a temperature of from 100°C to 220°C for a time from a few hours to several days until crystallization is completed: the crystals are then fired at a temperature from 300°C to 700°C and purified. The novel crystalline bodies are useful, for example, as catalysts for a number of chemical reactions. |