Process for the production of a core/shell zeolitic material having a CHA framework structure

摘要

The present invention relates to a process for the preparation of a zeolitic material having a CHA framework structure, said zeolitic material comprising zeolite crystals having a core-shell structure, wherein said process comprises the steps of
(1) providing a mixture comprising one or more sources for Z2O5, one or more sources for X2O3, optionally one or more structure directing agents, and seed crystals having a CHA framework structure, wherein the CHA framework structure of the seed crystals comprises YO2, X2O3, and optionally Z2O5, and wherein the seed crystals have a diameter of 450 nm or greater;(2) crystallizing the mixture provided in (1) to afford zeolite crystals comprising a core of seed crystal provided in step (1) and a shell crystallized on the seed crystal;

wherein Z is a pentavalent element, Y is a tetravalent element, and X is a trivalent element.

主权项

1. A process for the preparation of a zeolitic material having a CHA framework structure, said zeolitic material comprising zeolite crystals having a core-shell structure, wherein said process comprises the steps of
(1) providing a mixture comprising one or more sources for Z2O5, one or more sources for X2O3, optionally one or more structure directing agents, and seed crystals having a CHA framework structure, wherein the CHA framework structure of the seed crystals comprises YO2, X2O3, and wherein the seed crystals have a diameter of 450 nm or greater; and (2) crystallizing the mixture provided in (1) to afford zeolite crystals comprising a core of seed crystal provided in step (1) and a shell crystallized on the seed crystal; wherein Z is a pentavalent element, Y is a tetravalent element, and X is a trivalent element, wherein the framework structure of the seed crystals does not comprise Z2O5 in addition to X2O3 and YO2.