Acta Phys. -Chim. Sin. ›› 1990, Vol. 6 ›› Issue (02): 183-189.doi: 10.3866/PKU.WHXB19900211

• ARTICLE • Previous Articles     Next Articles

Studies on Acidity of Anhydrous LaHY Zeolite by In-Situ IR and Mas-NMR Method

Xue Zhi-Yuan; Zhu Lei-Ming; Dai Lin-Sen   

  1. Center of Analysis and Measurement, Fudan University, Shanghai
  • Received:1988-10-04 Revised:1989-05-30 Published:1990-04-15
  • Contact: Xue Zhi-Yuan

Abstract: Acidity of La~(3+)-exchanged HY zeolite has been studied by the measurements of adsorption on the in-situ IR system and MAS-NMR method. The results show that:
1.The IR bands at 3631 and 3556 cm~(-1) are all assigned to hydroxyl group of strong acidic sites. The band at 3531 cm~(-1) is assigned to nonacidic hydroxyl group, since it has no interaction with ammonia. It is possible that two hydroxyl groups coor-dinate with one La~(3+) directly; the band at 3520 cm~(-1) is assigned to weak acidic hy-droxyl group, because it has weak interaction with ammonia, and one hydroxyl group may coordinate with one La~(3+) directly.
2. The hydroxyl group at 3638 cm~(-1), which is in supercage of HY Zeolite, is of heterogeneity of actidity resulting from silicon atoms with different numbers of coordinated Aluminium.