Hydrolysis of Aluminum -Are All Gels Created Equal?

1990 ◽  
Vol 180 ◽  
Author(s):  
T. E. Wood ◽  
A. R. Siedle ◽  
J. R. Hill ◽  
R. P. Skarjune ◽  
C. J. Goodbrake
Keyword(s):  
Thermal Evolution ◽  
Mas Nmr ◽  
Aluminum Salt ◽  
Salt Solutions ◽  
Transition Alumina ◽  
Aluminum Ion ◽  
Hydrolysis Of

ABSTRACTThe nuclearity and structure of aluminum cations generated by the hydrolysis of aluminum salt solutions depends markedly on the method of preparation. This speciation affects not only the thermochemistry of processes leading to ceramics, but the microstructures of the ceramics themselves. A brief review of aluminum ion hydrolysis is presented along with a study of the thermal evolution of gels derived from aluminum salt solutions via several different hydrolysis methods. The observation of 5 - coordinate aluminum in a bulk transition alumina by MAS-NMR is reported. A new, high defect precursor of η-alumina dubbed “high-5 alumina” is described and the far reaching implications of this discovery are discussed.

HYDROLYTIC REACTIONS AND PROPERTIES OF DILUTE ALUMINUM SALT SOLUTIONS

1982 ◽  
Vol 62 (4) ◽  
pp. 559-569 ◽  
Author(s):  
S. SHAH SINGH
Keyword(s):  
Infrared Spectra ◽  
Aluminum Chloride ◽  
Aluminum Sulfate ◽  
Aluminum Nitrate ◽  
Aluminum Salt ◽  
Salt Solutions ◽  
Subtraction Technique ◽  
Dilute Solutions ◽  
Average Composition ◽  
Hydrolysis Of

Experiments were done to characterize the hydrolyzed solutions of aluminum nitrate, aluminum chloride and aluminum sulfate. The hydrolysis of the dilute solutions (10−3M) was accomplished under reflux process at 92 °C. The results showed that anions associated with Al have an effect on hydrolysis of aluminum and the order of ease of hydrolysis for similar concentrations of Al was NO3 > Cl > SO4. The average composition of the hydroxyaluminum cation (Aln(OH)m) was calculated as [Formula: see text] and [Formula: see text] for hydrolyzed solutions of Al(NO3)3, AlCl3, and Al2(SO4)3, respectively. The infrared spectra of the hydrolyzed species of aluminum were obtained by a subtraction technique and infrared peaks at 1410 cm−1 and 1085 cm−1 in the AlCl3 system and at 1435 cm−1 and 1070 cm−1 in the Al2(SO4)3 system were assigned to polynuclear hydroxyaluminum species having been formed due to reflux process.

Conditions for the formation of bayerite and gibbsite

1971 ◽  
Vol 38 (295) ◽  
pp. 358-368 ◽  
Author(s):  
W. J. Mchardy ◽  
A. P. Thomson
Keyword(s):  
Electron Microscopy ◽  
Carboxylic Acid ◽  
Electron Diffraction ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Acid Solutions ◽  
Salt Solutions ◽  
X Ray ◽  
Hydrolysis Of ◽  
Positively Charged

SummaryAluminium hydroxide gels have been prepared by the hydrolysis of amalgamated aluminium in water and by precipitation from aluminium salt solutions with an anion exchange resin in the hydroxyl form. The products crystallizing from such gels have been examined by electron microscopy and by X-ray and electron diffraction. Bayerite crystallizes as cone or pyramid-shaped particles and gibbsite as hexagonal plates or prisms. Two types of gel are postulated. The first type, pseudoboehmite, predominates in the absence of acids, is uncharged and rapidly crystallizes to bayerite; the second type, pregibbsite gel, occurs in carboxylic acid solutions, is positively charged and, in the absence of inorganic anions, crystallizes slowly to gibbsite.

The Similarity of Aluminum Salt Solutions and Aluminum Hydrosols

1934 ◽  
Vol 56 (9) ◽  
pp. 1844-1846 ◽  
Author(s):  
T. H. Whitehead ◽  
J. P. Clay
Keyword(s):  
Aluminum Salt ◽  
Salt Solutions

scholarly journals THE HYDROLYSIS OF ETHYL ACETATE BY NEUTRAL SALT SOLUTIONS.

1913 ◽  
Vol 35 (4) ◽  
pp. 396-418 ◽  
Author(s):  
William E. Henderson ◽  
David R. Kellogg
Keyword(s):  
Ethyl Acetate ◽  
Neutral Salt ◽  
Salt Solutions ◽  
Hydrolysis Of
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