Synthesis aluminophosphate molecular sieves

Similarly, reactive oxide mixtures are also used to synthesize aluminophosphate molecular sieves, usually starting from phosphoric acid along with the addition of alumina and silica sources analogous to those used in zeolite synthesis with a notable exception alkylammonium salts and amines were ultilized in structure-direchng and space filling to the exclusion of alkali hydroxide solutions and alkali metal salts. 

Heat-up rate effects have been investigated with respect to microwave synthesis of AlPO phases, however there are few publications concerning the heat-up effects in conventional heating [58]. There has also been at least one study of pH and H2O level on aluminophosphate crystallization [59]. A recent paper attempts to study the unique crystallization process of several aluminophosphate molecular sieve compositions [60]. 

We report here, for the first time, the synthetic procedures used to crystallize the aluminophosphate molecular sieve VPI-5. Two synthesis methods are illustrated. The step by step procedures are discussed in detail and reveal the precise nature of synthesizing VPI-5. 

Conditions for A1PQ4-H3 and MCM-1 Synthesis. From previous section it cSh Be concluded that as far as the coordination of A1 is concerned, AlPC -EU is a hybrid between the aluminum phosphate hydrates like variscite and metavariscite and the aluminophosphate molecular sieves. It can be expected that the synthesis conditions under which it crystallizes will also be intermediate between those of hydrates and molecular sieves. Literature together with the present new data seem to confirm this. 

Synthesis and Characterization of Metal Aluminophosphate Molecular Sieves... 

The synthesis of the first members of a new family of aluminophosphate molecular sieves (the ALPOs) was disclosed by Union Carbide scientists in the early 1980s (Wilson et al., 1982a,b). The zeotype frameworks of the ALPO structures can be pictured as alternating [AlOJ and [P02]+ units and so are electrically neutral with both Al and P occupying adjoining T-sites. 

The synthesis of aluminophosphate molecular sieves in 1980s represents a breakthrough in the development of microporous materials. Since then, much of the worldwide synthetic efforts have been directed toward nonsilicate microporous materials. Many novel framework topologies could be found with phosphates, and many other elements could be incorporated into phosphates to produce additional new framework topologies or new compositions. 

For nearly 50 years, chemists failed to synthesize molecular sieves with channels larger than 12-membered rings. It was not until 1988 that Davis et al. successfully synthesized the first aluminophosphate molecular sieve, VPI-5 ((H20)42[A118P18072]), with 18-membered-ring apertures (12.7 x 12.7 A).[10] The synthesis of VPI-5 is another milestone in the development of microporous materials. 

Subsequently, Xu et al. studied the microwave-enhanced ionothermal synthesis of aluminophosphate molecular sieves.[113] By using the ionic liquid l-ethyl-3-... 

K. Choi, D. Gardner, N. Hilbrandt, and T. Bein, Combinatorial Methods for the Synthesis of Aluminophosphate Molecular Sieves. Angew. Chem., Int. Ed., 1999, 38, 2891-2894. 

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