Redispersion of noble metals on supported catalysts
AssigneeExxon Research & Engineering Co.
InventorLloyd A. Pine
Life of this patent
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Abstract
Noble metals on supported zeolite-containing hydrocarbon conversion catalysts, which have been at least partially damaged by thermal and/or hydrothermal stresses resulting in a maldistribution of the supported metal, are redispersed to a highly active, high surface area state by contacting said catalyst with ethylenediaminetetraacetic acid (EDTA), or a salt thereof, to the point of incipient wetness and then removing said acid by heat treatment.
Claims15
A process for redispersing a noble metal on a supported zeolite-containing hydrocarbon conversion catalyst, at least a portion of said noble metal having become agglomerated, which comprises contacting said agglomerated catalyst with a solution containing at least a stoichiometric amount, based on the amount of noble metal present, of ethylenediaminetetraacetic acid or a salt thereof to incipient wetness for a time sufficient to redisperse a major portion of the metal throughout the catalyst, the temperature and pressure during said contacting being such that said solution is maintained in the liquid phase.
A process for redispersing a noble metal on a supported zeolite-containing hydrocarbon conversion catalyst, at least a portion of said noble metal having become agglomerated during contact with an oxygen-containing gas at a temperature ranging from about 700.degree. to 1100.degree. F., which comprises contacting said agglomerated catalyst with a solution containing at least a stoichiometric amount, based on the amount of noble metal present, of ethylenediaminetetraacetic acid or a salt thereof to incipient wetness for a time sufficient to redisperse a major portion of the metal throughout the catalyst, the temperature and pressure during said contacting being such that said solution is maintained in the liquid phase, and thereafter drying the redispersed catalyst.
Dependencies are inferred from the claim text.