Synthesis of BEA by dry gel conversion and its characterization

P. R. Hari Prasad Rao, C. A. Leon Y Leon, K. Ueyama, M. Matsukata

Research output: Contribution to journalArticle

64 Citations (Scopus)

Abstract

Zeolite BEA with SiO2/Al2O3 ratios ranging from 30 to 740 were crystallized at 413 and 453 K by the dry gel conversion technique. The particle size of the products increased with increasing SiO2/Al2O3 ratio as well as with increasing crystallization temperature. In as-synthesized BEA, the TEA+ ions interacting with Si-O- decomposed between 473 and 673 K and those interacting with Al-O- were cleaved between 673 and 798 K. During their elimination, the TEA+ ions interacting with Al-O- underwent higher degradation than those interacting with Si-O-. Chemical compositions showed the least influence on the fractions of decomposition product during the elimination between 473 and 673 K. The framework of H-BEA and NH4-BEA zeolites with SiO2/Al2O3 ratios ranging from 400 to 740 were stable even at 1373 K, whereas H-BEA with SiO2/Al2O3 = 30 was stable only up to 1173 K and became amorphous when calcined at 1373 K. After calcination at 1373 K, Na-BEA with SiO2/Al2O3 = 400 and 730 were transformed to tridymite (dense phase) whereas that with SiO2/Al2O3 = 30 became amorphous. The elimination of Na+ ions is necessary to have a BEA remain stable above 1173 K.

Original languageEnglish
Pages (from-to)305-313
Number of pages9
JournalMicroporous and Mesoporous Materials
Volume21
Issue number4-6
DOIs
Publication statusPublished - 1998 May

Keywords

  • Crystallization
  • Dry gel conversion
  • High silica zeolite
  • Interaction of TEA ions with zeolite
  • Thermal stability
  • Zeolite BEA (beta)

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials

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