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Quantitative relationships between boehmite and γ-alumina crystallite sizes

Published online by Cambridge University Press:  03 March 2011

J. Sánchez-Valente ,
F. Hernández-Beltrán ,
M.L. Guzman-Castillo ,
J.J. Fripiat  and
X. Bokhimi
J. Sánchez-Valente*
Affiliation:
Instituto Mexicano del Petróleo, 07730 Mexico D.F., Mexico
F. Hernández-Beltrán
Affiliation:
Instituto Mexicano del Petróleo, 07730 Mexico D.F., Mexico
M.L. Guzman-Castillo
Affiliation:
Instituto Mexicano del Petróleo, 07730 Mexico D.F., Mexico
J.J. Fripiat
Affiliation:
Instituto Mexicano del Petróleo, 07730 Mexico D.F., Mexico
X. Bokhimi
Affiliation:
Institute of Physics, The National University of Mexico (UNAM), 01000 Mexico D.F., Mexico
*
a) Address all correspondence to this author. e-mail: jsanchez@imp.mx
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Abstract

Nanocrystalline boehmite obtained by limited hydrolysis of aluminum tri-sec-butoxide or aluminum chloride was aged under different conditions before being calcined above the dehydroxylation temperature. When aging was carried out under hydrothermal conditions, the condensation of the structural units obeyed a first-order kinetic law with apparent activation energy of 12.2 kcal/mol. Under dehydroxylation conditions, the boehmite fragmentation is accounted for by a simple power law that links its volume to that of the resulting γ-alumina. The main variable is the volatile compounds content (water for instance) in the fresh sample. In terms of texture, a better organization of the initial nanoparticles in the boehmite means a lower surface area and larger pore diameter in the corresponding γ-alumina.

Keywords

Crystal growthKineticsTexture
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 5 , May 2004 , pp. 1499 - 1503
Copyright
Copyright © Materials Research Society 2004

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References

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