METHOD FOR PREPARING METALLOALUMINOPHOSPHATE (MEAPO) MOLECULAR SIEVES

摘要

The invention relates to a process for obtaining a metalloaluminophosphate (MeAPO) molecular sieve comprising the following steps in the order given:
a) providing an aqueous solution containing sources of at least 2 of the following:
- aluminium (Al),
- phosphorous (P),
- metal (Me);
b) adding a first MeAPO molecular sieve to the solution and modifying the pH before and/or after the addition of the first MeAPO molecular sieve to obtain an amorphous precursor;
c) separating the amorphous precursor from the water;
d) optionally washing and drying at a temperature below 450°C of the amorphous precursor;
e) contacting the amorphous precursor with an organic template-containing aqueous solution and with a source of Al, P or Me, which is not already present in step (a), optionally additional sources of Al and/or P and/or Me and optionally in the presence of aliphatic alcohols;
f) performing a crystallization of the amorphous precursor under autogeneous conditions so as to increase the concentration of the crystalline molecular sieve in respect to the initial precursor and so as to obtain a second MeAPO molecular sieve.