| Autor: |
G. C. Bye, J. G. Robinson |
| Rok vydání: |
2007 |
| Předmět: |
|
| Zdroj: |
Journal of Applied Chemistry and Biotechnology. 24:633-637 |
| ISSN: |
0375-9210 |
| Popis: |
Pseudoboehmite samples were prepared by ageing the amorphous hydroxide obtained by the hydrolysis of aluminium s-butoxide using water or aqueous ethanol. Further ageing resulted in the formation of a mixture of crystalline trihydroxides. The two re-crystallisation stages are accompanied by similar but opposite changes in the volume of the aqueous suspension but pseudoboehmite can only be identified by X-ray diffraction in a separated xerogel. Crystallinity of the latter was shown to be enhanced by preparation in 80% ethanol but at concentrations providing only a little more than the water needed for hydrolysis of the alkoxide a new modification of pseudoboehmite was observed. X-ray line broadening and displacement indicated that it possessed an even greater degree of lattice strain than exists in the common form. The composition and specific surface of a number of pseudoboehmite xerogels suggest that the major part of the water, in excess of that in the basic structures AlOOH, is present in a surface monolayer with a minor amount responsible for lattice strain. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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