US 5,207,814 A · Process for preparing monoliths of aerogels of metal oxides

Abstract

A process for the preparation of monoliths of aerogels of metal oxides, which aerogel is either constituted by one single oxide, or is constituted by a mixture of oxides, is disclosed, which process consists of the following operating steps: (a) the relevant metal alkoxide(s) is/are mixed with water in the presence of a catalyst of acidic character; (b) the so obtained mixture is hydrolysed; (c) a colloidal suspension of the oxide of a metal equal to, or different from, the metal(s) used in the (a) step is added to the hydrolysate; (d) the so obtained colloidal solution is caused to turn into a gel (gelation) having the desired shape and dimensions; (e) the gel is washed; (f) the gel is dried at values of temperature and pressure which are higher than the critical pressure and temperature values of the solvent used for the washing.

Claims12

Dependent claims

Process for preparing monoliths of an aerogel of at least one oxide, which process comprises the following operating steps:

(a) mixing an alkoxide of at least one metal with water in the presence of an acidic catalyst to form a mixture;
(b) hydrolyzing the mixture obtained in step (a) to form a hydrolysate;
(c) adding an oxide of at least one metal as a fine powder having a high specific surface area to the hydrolysate of step (b) to form a colloidal solution;
(d) causing the colloidal solution of step (c) to become a gel;
(e) washing the gel;
(f) drying the gel at values of temperature and pressure which are higher than the critical pressure and temperature values of the solvent used for the washing to form said monolith.

3 more elements

Dependencies are inferred from the claim text.

Process for preparing monoliths of aerogels of metal oxides

Life of this patent

Process for preparing monoliths of aerogels of metal oxides

Life of this patent

Abstract

Claims12