Selective demetallation of zeolites and related materials.

摘要

Crystalline molecular sieve materials are demetallated by a process comprising: (i) obtaining a sieve material wherein transition metal occupies framework cation positions, (ii) contacting the sieve material with a complexing agent, having a pH over 3, at 0-300 deg.C to remove the transition metal, and (iii) soln. phase, vapour phase, thermal, hydrothermal or mixts. thereof annealing. The sieve material is pref. a zeolite, zeolitic material, metal aluminophosphate, metal silico-aluminophosphate, metallo silicate , metal-stanno silicate, titano-silicate, zircono-silicate or mixts. thereof.