## Doctoral Dissertations

#### Title

A spectroscopic investigation of metal effects on poisoned and passivated fluid cracking catalysts (FCC's) and the sol-gel synthesis and characterization of multicomponent oxides

January 1994

#### Keywords

Chemistry, Inorganic

Ph.D.

#### Abstract

Naphthenate, phthalocyanine and porphyrin ligands have been used to represent vanadium and nickel contaminants in petroleum feedstocks. Lanthanum HY zeolites were then V-loaded with each of these species and the vanadium deposited was passivated with tetraphenyl tin. Materials were studied by luminescence emission and lifetime measurements after drying, calcination and steam aging. Results suggest that the naphthenates are degraded most readily followed by phthalocyanines and by porphyrins. Vanadium after the oxidative decomposition (in air) of the naphthenate and phthalocyanine ligands forms $\rm V\sb2O\sb5$. When vanadyl mesotetraphyenl porphyrin was used to metal load the LaY crystals, $\rm V\sb2O\sb5$ formation was observed only after steam aging. Tin addition minimizes vanadia formation irrespective of the vanadium contaminant used. Luminescence can detect $\rm V\sb2O\sb5$ formation when LRS (and XRD) cannot.^ Sol-gel techniques have been used to synthesize ternary and quanternary metal oxides. Oxides such as aluminates, silicates, titanates, ferrites and cuprates were synthesized at lower processing temperatures than conventional solid state methods. Powders were produced by heating the dry gel to 900$\sp\circ$C for 20 hours. Under basic conditions, glasses can be produced and fibers could be drawn from the sol. And when the counter cation was UO$\sb2\sp{2+}$ a foam-like structure was formed.^ Substituted 214 compounds were synthesized, as well as the superconductor 123. Thin films of 123 on silica were produced in solution with the use of an immersion heater. The synthesis was done in an alcohol-water solution and no special precautions were taken in the preparation of the precursors.^ Lead titanates and substituted lead titanates were synthesized using sol-gel techniques. Special handling procedures were not required with a new heating apparatus developed. Particle sizes were determined by X-ray line broadening and SEM. The green density was $>$60% and the shrinkage was $<$8%. ^

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