Synthesis of MeAPO Molecular Sieves

In Section 3.4.2, the aluminophosphate zeolites were described, now a more detailed description of the synthesis methods of these materials ensues. The development of crystalline, microporous phosphate-based oxides was initiated in 1982 with the synthesis of materials with aluminophosphate composition [127], A new development in this field was the synthesis of silico-aluminophosphates in 1984 [66], The number of structures and types of phosphate-based crystalline microporous oxides increased with the synthesis of metal aluminophosphates [128-131], obtained by the substitution of A1 by Ga [72], and Be [132], Zn [133], and P by As and V [134,135], Currently, there are about 18 different elements, that is, Li(I), Co(II), Fe(II), Mg(II), Mn(II), Zn(II), Be(II), Ni(II), Sn(II), B(III), Al(III), Ga(III), Fe(III), Cr(III), Si(IV), Ge(IV), Ti(IV), As(V), and V(V) that can be combined with P(V) in different framework types [136], 

Crystalline microporous aluminophosphates containing framework metals, that is, MeAPO, constitute an interesting group of molecular sieves [29,137], These materials are synthesized hydrothermally between 100°C and 250°C using organic templates, and crystallize into different structure types. 

A typical synthesis procedure is summarized by the following steps [29]  

Alumina is slurried in half quantity of water, which will be used for the synthesis. 

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