Aluminosilicophosphate zeolites

The nomenclature used throughout this paper designates the structural type by the letter of the most closely related phosphorus-free synthetic zeolite as used in the Union Carbide laboratories (4, 5). Table II in Ref. 5 contains a description of the synthetic zeolites described here. For the aluminosilicophosphate zeolites, these letter designations are prefixed by P to indicate that the zeolite framework contains phosphorus substituted in the tetrahedral (Si, Al) site. For example, the phosphate zeolite structurally related to Type A zeolite is designated P-A P-R zeolite is the phosphate zeolite related to zeolite R, a synthetic sodium aluminosilicate zeolite with a chabazite type framework structure (5). The aluminosilicophosphate zeolites will be abbreviated to phosphate zeolites or phosphorus-substituted zeolites throughout this paper. 

Ternary reaction diagrams showing the regions of gel composition for synthesizing the phosphate zeolites are shown in Figures 1-3 for the sodium aluminosilicophosphate zeolites, and in Figures 4 and 5 for the analogous potassium system. 

Zeolite P-C (Analcime Structure Type). Zeolite P-C was crystallized from sodium aluminosilicophosphate gels prepared by simultaneously... 

Zeolite P-R and P-G (Chabazite Structure Type). Zeolite P-G was crystallized from potassium aluminosilicophosphate gels prepared by the same procedure used in the preparation of P-W gel. Zeolite P-R was crystallized in the sodium system by using NaOH in place of KOH. The reactant gel was crystallized at 125°-175°C and saturated water vapor pressure for 48-120 hours. Zeolite P-G containing up to 21 wt % P2O5, and zeolite P-R containing up to 16 wt % P2O5 were synthesized. 

Zeolite P-L (L Structure Type). Zeolite P-L was synthesized from aluminosilicophosphate gels prepared by the procedure described for zeolites P-W and P-G using KOH solution as the source of base. The use of a solid silica source such as Cab-O-Sil facilitates the formation of P-L... 

The formation of the aluminosilicophosphate gel requires a reactive form of phosphorus such as phosphoric acid for its incorporation into the gel structure and zeolite framework. The mere presence of a phosphate salt such as sodium metaphosphate in the reactant gel will not result in phosphorus incorporation in the zeolite crystal lattice. 

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