Synthesis of Fully Dehydrated Partially Cs+-exchanged Zeolite Y (FAU, Si/Al = 1.56), |Cs45Na30|[Si117Al75O384]-FAU and Its Single-crystal Structure

• Published in: Bulletin of the Korean Chemical Society pp. 1285 - 1292
• Main Authors: Sung Man Seo, Ghyung Hwa Kim, Seok Hee Lee, Jun-seok Bae, 임우택
• Format: Journal Article
• Language: English
• Published: 대한화학회 01.06.2009
• Subjects: 화학
• ISSN: 0253-2964; 1229-5949
• DOI: 10.5012/bkcs.2009.30.6.1285

Large single crystals of zeolite, |Na75|[Si117Al75O384]-FAU (Na-Y, Si/Al = 1.56), were synthesized from gels with composition of 3.58SiO2 : 2.08NaAlO2 : 7.59NaOH : 455H2O : 5.06TEA : 2.23TCl. One of these, a colorless single-crystal was ion exchanged by allowing aqueous 0.02 M CsOH to flow past the crystal at 293 K for 3 days, followed by dehydration at 673 K and 1 × 10-6 Torr for 2 days. The crystal structure of fully dehydrated partially Cs+-exchanged zeolite Y, |Cs45Na30|[Si117Al75O384]-FAU per unit cell (a = 24.9080(10) Å) was determined by single-crystal X-ray diffraction technique in the cubic space group Fd 3 m at 294(1) K. The structure was refined using all intensities to the final error indices (using only the 877 reflections with Fo > 4σ(Fo)) R1 = 0.0966 (Based on F) and R2 = 0.2641 (Based on F2). About forty-five Cs+ ions per unit cell are found at six different crystallographic sites. The 2 Cs+ ions occupied at site I, at the centers of double 6-ring (D6Rs, Cs-O = 2.774(10) Å and O-Cs-O = 88.9(3) and 91.1(3)o). Two Cs+ ions are found at site I’ in the sodalite cavity; the Cs+ ions were recessed 2.05 Å into the sodalite cavity from their 3-oxygen plane (Cs-O = 3.05(3) Å and O-Cs-O = 77.4(13)o). Site-II’ positions (opposite single 6-rings in the sodalite cage) are occupied by 7 Cs+ ions, each of which extends 2.04 Å into the sodalite cage from its 3-oxygen plane (Cs-O = 3.067(11) Å and O-Cs-O = 80.1(3)o). The 26 Cs+ ions are nearly three-quarters filled at site II in the supercage, being recessed 2.34 Å into the supercage (Cs-O = 3.273(8) Å and O-Cs-O = 74.3(3)o). The 4 Cs+ ions are found at site III deep in the supercage (Cs-O = 3.321(19) and 3.08(3) Å), and 4 Cs+ ions at another site III’ (Cs-O = 2.87(4) and 3.38(4) Å). About 30 Na+ ions per unit cell are found at one crystallographic site; The Na+ ions are located at site I’ in the sodalite cavity opposite double 6-rings (Na-O =2.578(11) Å and O-Na-O = 97.8(4)o). KCI Citation Count: 11