High pore volume and pore diameter aluminum phosphate and method of making the same
AssigneeW. R. Grace & Co.-Conn.
InventorsRimantas Glemza, Yves O. Parent
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Abstract
Aluminum phosphate compositions are provided which are characterized simultaneously by high porosity and phosphorous-to-aluminum ratios of approximately 1.0. The high porosity of these compositions is a function of high pore volume coupled with low surface area, resulting in high average pore diameter. These materials have excellent properties as catalysts and catalyst supports. Methods of making the compositions are also provided.
Claims16
A homogeneous, single-phase amorphous aluminum phosphate composition in which phosphorus and aluminum are present in a ratio of from about 0.8:1 to about 1:1 and which is characterized by a total pore volume of at least about 1.0 cubic centimeters per gram and a surface area of between about 200 and about 400 square meters per gram, the combination of pore volume and surface area yielding an average pore diameter of at least about 125 Angstroms.
A process for preparing high pore volume homogeneous aluminum phosphate composition, said process comprising:
- (a) forming an acidic aqueous solution of one or more aluminum salts and one or more phosphate salts, said solution having a P/Al ratio of about 0.8:1 to about 1:1,
- (b) partially neutralizing the acidic aqueous solution by the rapid addition of ammonia gas, with mixing, until gelation occurs thereby forming a hydrogel,
- (c) neutralizing the hydrogel formed in step (b) by soaking the hydrogel for at least about 2.0 hours in a concentrated aqueous basic solution of sufficient strength to yield an end pH of about 8.0-9.0 at a temperature of about 60.0 to 90.0.degree. C.,
- (d) washing the neutralized hydrogel in water or dilute ammonium hydroxide solution,
- (e) exchanging the washed hydrogel with alcohol, acetone, or ethyl acetate, and
- (f) drying the exchanged hydrogel to obtain the composition.
A process for preparing high pore volume, homogeneous aluminum phosphate compositions comprising:
- (a) forming an acidic aqueous solution comprising aluminum nitrate, aluminum chloride hydrate, aluminum bromide, aluminum bromate, aluminum chlorate or aluminum iodide hydrate, and orthophosphoric acid, ammonium phosphate or ammonium phosphate, dibasic, sail solution having a P/Al ratio of about 0.8:1 to about 1:1,
- (b) partially neutralizing the acidic aqueous solution by the rapid addition of ammonia gas, with mixing, until gelation occurs,
- (c) neutralizing the hydrogel formed in step (b) by soaking said hydrogel in a concentrated aqueous ammonium hydroxide or sodium hydroxide solution at a temperature of about 60.0 to 90.0.degree. C.,
- (d) washing the neutralized hydrogel in water or dilute ammonium hydroxide solution,
- (e) exchanging the washed hydrogel with alcohol, acetone or ethyl acetate, and
- (f) drying the exchanged hydrogel to obtain the composition.
Dependencies are inferred from the claim text.