Silica foam compositions
AssigneeBoard of Trustees operating Michigan State University
InventorsThomas J. Pinnavaia, Thomas R. Pauly, Seong-Su Kim
Life of this patent
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Abstract
Porous inorganic silica foam compositions are derived from water soluble silicate precursors and swollen non-ionic polymer templates are described. The compositions are useful as catalyst supports and as catalysts in hydrocarbon cracking and organic reactions, among other applications.
Claims18
A mesoporous to small macroporous cellular silica foam composition with interconnected cells joined at nexus defining cellular pores with open windows between the cellular pores and with SiO4 tetrahedra crosslinked to four adjacent silicon sites (Q4), to three adjacent silicon sites (Q3), and to two adjacent silicon sites (Q2), the ratio of Q4/(Q3+Q2) being between 2.5 and 8.
A hybrid mesoporous to small macroporous cellular silica foam composition with interconnected cells joined at nexus defining cellular pores with open windows between the cellular pores and with SiO4 tetrahedra of cell walls crosslinked to four adjacent silicon sites (Q4), to three adjacent silicon sites (Q3), and to two adjacent silicon sites (Q2) the ratio of Q4/(Q3+Q2) being between 2.5 and 8, containing a surfactant and an organic co-solvent which swells the surfactant in the cellular pores.
A process for the preparation of a mesoporous to small macroporous cellular silica foam composition with interconnected cells joined at nexus which comprises:
- (a) providing an aqueous mixture of a surfactant and an organic co-solvent which swells the surfactant as emulsifying agents;
- (b) providing a solution of a water soluble silicate;
- (c) providing an acid in an amount sufficient to cause precipitation of silica from the silicate solution at a pH between about 5.0 and 9.0;
- (d) combining the reagents in parts (a), (b) and (c) at a temperature greater than −20° C.;
- (e) allowing the reaction mixture of step (d) to age for a minimum time of 5 minutes at one or more temperatures above −20° C.;
- and
- (f) recovering the precipitated product from the solution.
Dependencies are inferred from the claim text.