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US 4,021,447 AGranted
Synthesis of zeolite ZSM-4
AssigneeMobil Oil Corporation
InventorsMae K. Rubin, Charles J. Plank, Edward J. Rosinski
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AssigneeMobil Oil Corporation
InventorsMae K. Rubin, Charles J. Plank, Edward J. Rosinski
Estimating the term…
As synthesized by previous methods, ZSM-4 zeolites are crystallized in the presence of substantial amounts of a tetramethylammonium hydroxide or halide. When synthesized in this way, they contain the tetramethylammonium cation as well as a metal cation such as sodium. To obtain a more catalytically active form, the sodium ion must be exchanged to very low levels. Catalysts prepared in this manner have been found to be quite low in stability. By synthesizing these zeolites in the presence of pyrrolidine or choline salts, ZSM-4 having a different organic nitrogen containing cation but the same crystal structure as previously prepared ZSM-4 is obtained. Catalysts made therefrom are, surprisingly, much more stable than those prepared from ZSM-4 made by previous methods.
A synthetic crystalline aluminosilicate zeolite having a composition as synthesized in terms of moles of oxides as follows:
In a method for synthesizing a ZSM-4 crystalline aluminosilicate zeolite containing an organic nitrogen cation, wherein a reaction mixture comprising sources of silica, alumina, alkali metal, water and organonitrogen cation precursor is prepared and maintained under conditions of temperature and pressure to effect crystallization of said zeolite, the improvement wherein said precursor is derived from a member of the group consisting of choline, choline salts and pyrrolidine.
Dependencies are inferred from the claim text.