Alumina sol, process for preparing the same, process for preparing alumina molding using the same, and alumina-based catalyst prepared thereby
OwnerGoro Satoinventor
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Abstract
An alumina sol, containing a small amount of water of crystallization inside the crystal lattice of boehmite, having high mechanical strength, properties suitable for use as an alumina adsorbent or carrier, and the ability to be formed without additional concentration. The alumina sol comprises a fibrous boehmite having the molecular formula Al2O3.1.05-1.30 H2O with the weight average diameter and the weight average length being respectively in the range of 3 to 50 nm and in the range of 30 to 3000 nm, and has an alumina concentration of 15 to 60% by weight.
Claims8
A process for producing an alumina sol comprising fibrous crystalline boehmite exhibiting ρ-crystal structure, comprising mixing alumina produced by rapid heating dehydration of aluminum hydroxide with alumina having higher solubility than boehmite in an amount of 0 to 95% by weight in terms of oxide, adding at least one inorganic monobasic acid, and then subjecting the resulting mixture to hydrothermal treatment at a temperature of 70 to 350° C. in the presence of water, said hydrothermal treatment being carried out with stirring accompanied by substantially slight shearing, without stirring or a combination thereof, and said mixture having a chemical composition by mol represented by aAl2O3.bHA.cH2O wherein HA is a sum of effective acid and a, b and c are numbers satisfying the following relation:
- k=(b/a)·(b/c)
- wherein the k value is in the range of 0.0005 to 0.01, and containing alumina in a concentration of 5% to 60% by weight.
A process for producing an alumina sol comprising fibrous crystalline boehmite exhibiting ρ-crystalline structure, comprising mixing alumina produced by rapid heating dehydration of aluminum hydroxide with alumina having higher solubility than boehmite in an amount of 0 to 95% by weight in terms of oxide, adding at least one lower aliphatic monocarboxylic acid, and then subjecting the resulting mixture to hydrothermal treatment at a temperature of 70 to 350° C. in the presence of water, said hydrothermal treatment being carried out with stirring accompanied by substantially slight shearing, without stirring or a combination thereof, and said mixture having a chemical composition by mol represented by aAl2O3.bHA.cH2O wherein HA is a sum of effective acid and a, b and c are numbers satisfying the following relation:
- k=(b/a)·(b/c)
- wherein the k value is in the range of 0.002 to 0.05, and containing alumina in concentration of 5 to 60% by weight.
Dependencies are inferred from the claim text.