Redispersing noble metal on hydrocarbon conversion catalyst - by treatment with soln. of ethylene-di:amine tetra:acetic acid or salt

摘要

A noble metal is redispersed on a supported hyrocarbon conversion catalyst contg. a zeolite, when at least part of the metal has become agglomerated, by contacting the catalyst with a soln. contg. the stoichiometric amt., w.r.t. the metal, of EDTA or a EDTA salt, to incipient wetness. The temp. and pressure are such that the soln. is kept in the liq. phase. An aq. soln. of EDTA (salt) is pref. The salts may be those of Gp. I metals, NH4 or alkyl-ammonium; ammonium and/or alkyl-ammonium salts are pref. Use of excess soln is to be avoided. Treatment is partic. at ambient temp. and pressure for 1-100 hrs.. The metals is not leached from the support. EDTA (salt) does not attack the support.