US 5,672,556 A · Crystalline silicate compositions and method of preparation

Abstract

Crystalline silicate compositions having unique combinations of framework-confined uniform mesopores and textural mesopores and to a method for their preparation. The compositions typically possess a small particle size of .ltoreq.400 .ANG., a ratio of textural to framework-confined mesoporosity of 0.2 or greater, and a novel ability to discriminate, to adsorb, and with a metal element in the mesopores, to catalytically transform large organic molecules. The method for the formation of the mesoporous structure is accomplished by hydrogen bonding between a non-ionic amine template and a non-ionic inorganic oxide precursor followed by hydrolysis and crosslinking under mild reaction conditions. The templated products of this invention are preferably obtained using water as a hydrolyzing reagent and an alcohol as a co-solvent. The framework-confined uniform mesopore size can be expanded without the use of an auxiliary organic (pore expanding agent). The template can be easily recovered and recycled, preferably, by ethanol extraction.

Claims23

Dependent claims

A calcined crystalline silicate containing composition having uniform framework-confined mesopores having a pore size greater than about 20 .ANG. as determined by N.sub.2 adsorption and textural mesopores and consisting essentially of particles with a size of less than about 400 .ANG., two hysteresis loops in a N.sub.2 adsorption-desorption isotherm, a ratio of textural to framework mesopores of at least about 0.2, a specific surface area of 300 to 1500 square meters per gram, prepared by a method which comprises reacting a neutral silicon-containing inorganic oxide precursor, a Ti containing inorganic oxide precursor and a neutral amine template in water and an organic co-solvent to form a reaction product and hydrolysis of the reaction product and has a composition as follows:

L.sub.x M.sub.y Si.sub.z O.sub.q
wherein L is optional and is at least one trivalent element selected from the group consisting of B, Al, Ga, Cr and Fe;
M is Ti;
x, y, z and q are the molar parts of L, M, Si and O, respectively and wherein x when L is present is about 0.001 and 0.5;
y is between about 0.001 and 0.4;
z is between about 0.4 and 1 and q is between about 1 and 3.

3 more elements

A method for preparation of a synthetic, crystalline silicate composition which can be calcined comprising:

(a) preparing an aged, non-ionic silicon precursor solution containing an organic co-solvent with stirring at a temperature of at least 0.degree. C. for at least 5 minutes wherein the solution can optionally contain a metal as an inorganic oxide precursor;
(b) preparing a homogeneous solution of a non-ionic amine template in a hydrolysis agent selected from the group consisting of water, the organic co-solvent and mixtures thereof with stirring at a temperature between about 0.degree. and 100.degree. C.;
(c) mixing of the solutions of steps (a) and (b) at a temperature between about 0.degree. and 100.degree. C. to form a gel which is aged for at least thirty minutes to form a crystalline product;
and
(d) separating the template and at least some of the hydrolysis agent from the crystalline product, wherein the template produces a pore size of greater than 20 .ANG. in the silicate composition.

2 more elements

Dependencies are inferred from the claim text.

Crystalline silicate compositions and method of preparation

Life of this patent

Crystalline silicate compositions and method of preparation

Life of this patent

Abstract

Claims23