Small crystal LTL framework type zeolites

摘要

Small crystal LTL framework type zeolites, characterized as polycrystalline aggregates, each of the aggregates comprising a plurality of spherical or cube-like crystallites and wherein each crystallite has an average crystallite size of from 10 to 50 nm, are disclosed. Such zeolites can be prepared by hydrothermal conversion of FAU framework type zeolites at low H2O/SiO2 mole ratios.

主权项

1. A method for preparing an LTL framework type zeolite, characterized as polycrystalline aggregates, each of the aggregates comprising a plurality of spherical or cube-like crystallites and wherein each crystallite has an average crystallite size of from 10 to 50 nm, the method comprising:
(a) preparing a reaction mixture comprising:
(1) a FAU framework type zeolite;(2) hydroxide ions;(3) a source of alkali metal (M); and(4) water; wherein the reaction mixture comprises, in terms of mole ratios, the following:SiO2/Al2O3 5 to 60M/SiO20.15 to 0.50OH/SiO20.15 to 0.50H2O/SiO2 3 to 12 where M is potassium or a mixture of potassium and one or more other alkali metals; and (b) subjecting the reaction mixture to crystallization conditions sufficient to form crystals of the LTL framework type zeolite.