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  • 09월 04일 13시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

Crystal Structure Showing the Dehydration, Deamination, and Dealumination of Partially NH4+-exchanged Zeolite Y (FAU), |Na33H26(Al5O4)|[Si126Al66O384]-FAU

등록일
2009년 8월 14일 12시 54분 14초
접수번호
0923
발표코드
34P88포 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
목 <발표Ⅰ>
발표형식
포스터
발표분야
물리화학
저자 및
공동저자
서성만, 김후식, 김경화1, 이오석, 임우택
안동대학교 응용화학과, Korea
1포항가속기연구소 빔라인부 엑스선운영2팀, Korea
A single crystal of zeolite Y, |Na71|[Si121Al71O384]-FAU, was ion exchanged to generate |(NH4)38Na33|[Si121Al71O384]-FAU. This was then vacuum dehydrated at 673 K, and, without re-exposure to the atmosphere, its structure was determined crystallographically using synchrotron X-radiation in the cubic space group Fd3-m at 294 K. It was refined to the final error index R1 = 0.0532 with 522 reflections for which Fo > 4σ(Fo). The composition (best integers) is determined to be |Na33H26(Al5O4)|[Si126Al66O384]-FAU which means fully dehydration, deamination, and dealumination were achieved. The 33 Na+ ions per unit cell were found at two crystallographically distinct positions: nine at site I (in the centers of the D6Rs) and 24 at site II (in supercages opposite S6Rs). The 2.5 sodalite units contained a dimeric tetrahedral aluminate cation (Al-O = 1.40(8) and 1.60(8) Å) at its center. Each [Al5O4]7+ cation coordinates to framework oxygen of D6Rs with tetrahedral manner. This work demonstrates that it is possible to obtain large amount of dealuminated species within the H-Y zeolite framework which should enhance the acidity of adjacent sites for higher catalytic activity.

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