Hostname: page-component-76fb5796d-zzh7m Total loading time: 0 Render date: 2024-04-26T10:46:25.676Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Kotanigawa, T., Yamamoto, M., Utiyama, M., Hattori, H. and Tanabe, K., The influence of preparation methods on the pore structure of alumina. Appl. Catal. 1, 185 (1981).CrossRefGoogle Scholar
2Beguin, B., Garboswki, E. and Primet, M., Stabilization of alumina toward thermal sintering by silicon addition. J. Catal. 127, 595 (1991).CrossRefGoogle Scholar
3Knözinger, H. and Ratnasamy, P., Catalytic aluminas: Surface models and characterization of surface sites. Cat. Rev.-Sci. Eng. 17, 31 (1978).Google Scholar
4Chen, F.R., Davis, J.G. and Fripiat, J.J., Aluminum coordination and Lewis acidity in transition aluminas. J. Catal. 133, 263 (1992).Google Scholar
5Bokhimi, X.J.A.Toledo-Antonio, Guzmán-Castillo, M.L. and Hernández-Beltrán, F., Relationship between crystallite size and bond lengths in Boehmite. J. Solid State Chem. 159, 32 (2001).Google Scholar
6Bokhimi, X., Toledo-Antonio, J.A., Guzmán-Castillo, M.L. and Hernández-Beltrán, F., Dependence of boehmite thermal evolution on atom bond length and crystal size. J. Solid State Chem. 161, 319 (2001).Google Scholar
7Guzmán-Castillo, M.L., Bokhimi, X., Toledo-Antonio, J.A., Salmones, J. and Hernández-Beltrán, F., Effect of Boehmite crystallite size and steaming on alumina properties. J. Phys. Chem. 105, 2099 (2001).Google Scholar
8Bokhimi, X. and Sánchez-Valente, J., Crystallization of sol-gel boehmite via hydrothermal annealing. J. Solid State Chem. 166,182 (2002).Google Scholar
9Sánchez-Valente, J., Bokhimi, X. and Hernández, F., Physicochemical and catalytic properties of sol-gel aluminas aged under hydrothermal conditions. Langmuir 19, 3583 (2003).CrossRefGoogle Scholar