Tin-containing zeolitic material having an MWW-type framework structure

摘要

A tin containing zeolitic material having an MWW-type framework structure (Sn-MWW), having a tin content of at most 2 weight-%, calculated as element and based on the weight of the Sn-MWW, and having an X-ray diffraction pattern comprising peaks at 2 theta diffraction angles of (6.6±0.1)°, (7.1±0.1)°, and (7.9±0.1)°.

主权项

1. A process for preparing a tin-containing zeolitic material having an MWW-type framework structure (Sn-MWW) comprising
(i) providing a boron-containing zeolitic material having an MWW framework structure comprising SiO2 and B2O3 (B-MWW); (ii) deboronating the B-MWW by treating the B-MWW provided in (i) with a liquid solvent system having a pH in the range of from 5.5 to 8; (iii) incorporating Sn into deboronated B-MWW obtained from (ii) by a process comprising
(iii.1) preparing an aqueous synthesis mixture containing the deboronated B-MWW obtained from (ii), an MWW template compound, and a tin source, wherein in the synthesis mixture, the molar ratio of Sn, calculated as SnO2, relative to Si, calculated as SiO2 and contained in the deboronated B-MWW, is at most 0.015:1;(iii.2) hydrothermally synthesizing a tin-containing zeolitic material having an MWW-type framework structure from the synthesis mixture obtained from (iii.1) thereby obtaining a tin-containing zeolitic material having an MWW-type framework structure in its mother liquor;(iii.3) separating the tin-containing zeolitic material having an MWW-type framework structure obtained from (iii.2) from its mother liquor; (iv) treating the tin-containing zeolitic material having an MWW-type framework structure obtained from (iii) with an aqueous solution having a pH of at most 5 thereby obtaining the Sn-MWW having an Sn content of at most 2 weight-%, calculated as element and based on the weight of the Sn-MWW, and optionally separating the Sn-MWW from the aqueous solution.