| abstract |
The present invention relates to a process for the preparation of a micro-meso porous material which comprises: (a) preparing a mixture starting from a tetraalkylortho-silicate, a C3-C6 alkyl alcohol or dialcohol, a tetra-alkylammonium hydroxide having the formula R1(R2)3N-OH wherein R1 is a C3-C7 alkyl and R2 is a C1 or C3-C7 alkyl, optionally in the presence of one or more metal compounds, in which the molar ratios are within the following ranges: alcohol/sio2 < or equal to 20; R1(R2)3N-OH/sio2 = 0.05-0.4; H2O/sio2 = 1-40; metal oxides/sio2 = 0-0.02; (b) subjecting this mixture to hydrolysis and subsequent gelation at a temperature of between 20 DEG C and a temperature close to the boiling point of the alcohol or mixture of alcohols present; (c) subjecting the gel obtained to drying and calcination. The material thus obtained is characterized by a surface area of more than 500 m<SP>2</SP>/g, a pore volume of between 0.3 and 1.3 ml/g, an average pore diameter of less than 40 A and an X-ray diffraction spectrum (XRD) from powders which does not have a crystalline structure, but possibly a widespread ""scattering"" with angular values of not more than 2θ = 5 DEG. Said material can be conveniently used as a heterogeneous catalyst, as an adsorbent or as a carrier for catalysts in industrial processes, in the fields of refining, petrochemistry, basic chemistry and fine chemistry. |