Preparation and structural study of fully dehydrated, highly Mg^sup 2+^-exchanged zeolite Y (FAU, Si/Al = 1.56) from undried methanol solution

• Published in: Journal of porous materials 2014-10, Vol.21 (5), p.659
• Main Authors: Kim, Hu Sik, Choi, Sang June, Lim, Woo Taik
• Format: Article
• Language: English
• ISSN: 1380-2224; 1573-4854
• DOI: 10.1007/s10934-014-9812-9

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Single-crystal of fully dehydrated, Mg^sup 2+^-exchanged zeolite Y, |Mg^sub 34.5^Na^sub 6^|[Si^sub 117^Al^sub 75^O^sub 384^]-FAU (Si/Al = 1.56), was successfully prepared from undried methanol solution (water concentration 0.02 M). A crystal of Na-Y was treated with 0.05 M MgCl^sub 2^ ·6H2O in the solvent at 333 K, followed by vacuum dehydration at 723 K and 1 × 10^sup -6^ Torr for 2 days. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques, in the cubic space group ... at 100 K. It was refined to the final error indices R ^sub 1^/wR ^sub 2^ = 0.0587/0.2210 with 1,294 reflections for which F ^sub o^ > 4σ(F ^sub o^). In the structure of |Mg^sub 34.5^Na^sub 6^|[Si^sub 117^Al^sub 75^O^sub 384^]-FAU, 34.5 Mg^sup 2+^ ions per unit cell are found at four different crystallographic sites: 15 per unit cell are located at site I at the center of the hexagonal prism [Mg-O = 2.216(2) Å], two are at site I' in the sodalite cavity near the hexagonal prism [Mg-O = 2.20(3) Å], only one is located at site II' in the sodalite cavity [Mg-O = 2.197(23) Å], and the remaining 16.5 are at site II near single 6-oxygen rings in the supercage [Mg-O = 2.103(3) Å]. The residual 6 Na^sup +^ ions per unit cell are found at site II [Na-O = 2.218(7) Å]. No water molecules are found in this structure.[PUBLICATION ABSTRACT]