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US 7,740,821 B2Granted
Highly condensed mesoporous silicate compositions and methods
AssigneeUniversity of Massachusetts
InventorsJames J. Watkins, David M. Hess
Life of this patent
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Abstract
A mesoporous silicate is prepared by a method that includes combining a silicate precursor, a bifunctional catalyst, and a structure-directing surfactant in an aqueous medium having a pH of about 4 to about 10. A mesoporous silicate forms as an aqueous suspension and can then be isolated. The mesoporous silicate can be formed under mild conditions of temperature and pH, and it exhibits a surprisingly high degree of network condensation.
Claims5
A method of preparing a mesoporous silicate, comprising:
- combining
- a silicate precursor,
- a bifunctional catalyst, and
- a structure-directing surfactant
- in an aqueous medium having a pH of about 4 to about 10 to form an aqueous suspension comprising a mesoporous silicate;
- and
- isolating the mesoporous silicate;
- wherein the isolated mesoporous silicate has a degree of network condensation characterized by a value of Q4/(Q3+Q2) of at least 3, wherein Q4 represents the fraction of silicon centers bound to four other silicon centers via bridging oxygen atoms, Q3 represents the fraction of silicon centers bound to three other silicon centers via bridging oxygen atoms, and Q2 represents the fraction of silicon centers bound to two other silicon centers via bridging oxygen atoms.
5 more elements
A method of preparing a mesoporous silicate, comprising:
- combining
- a silicate precursor,
- a bifunctional catalyst, and
- a structure-directing surfactant
- in an aqueous medium having a pH of about 4 to about 10 to form an aqueous suspension comprising a mesoporous silicate;
- and
- isolating the mesoporous silicate;
- wherein the structure-directing surfactant is an alpha-(C12-C24-hydrocarbyl)-omega-hydroxy-poly(oxy-1,2-alkanediyl).
5 more elements
A method of preparing a mesoporous silicate, comprising:
- combining tetraethylorthosilicate with an aqueous solution at a temperature of about 10 to about 30° C. and allowing the resulting mixture to age for about 0.5 to about 10 days, thereby forming an aqueous suspension of a mesoporous silicate solid;
- wherein the aqueous solution comprises
- about 0.01 to about 0.1 mole per liter of cysteamine,
- about 0.001 to about 0.1 mole per liter of potassium phosphate,
- about 0.02 to about and 0.2 moles per liter of sodium chloride, and
- about 0.01 to about 0.1 mole per liter of an alpha-(C12-C24-alkyl)-omega-hydroxy-poly(oxy-1,2-ethanediyl), an alpha-(C12-C24-alkenyl)-omega-hydroxy-poly(oxy-1,2-ethanediyl), or a mixture thereof;
- and
- wherein the tetraethylorthosilicate and the aqueous solution are combined in a weight ratio of about 1:4 to about 1:1;
- separating the mesoporous silicate solid from the aqueous suspension;
- and
- washing the separated mesoporous silicate solid.
8 more elements
Dependencies are inferred from the claim text.