Orientation of Chemical Properties by Direct Synthesis of Molecular Sieves
This subject was discussed on the basis of a broad collective experimental experience and not only that of the presented papers (1). The classical concept of a nuclei as a critically sized “species” allowing spontaneous growth in a system by virtue of lowering the free energy of the “solution” — was accepted. This may occur spontaneously in a supersaturated system or by the addition of such material promoters from an external source. The issue of whether the latter are nuclei or seeds was discussed at length, and depending on the specific zeolite or synthesis slurry in question, both mechanisms may be invoked. Nuclei in this case are structureless in the sense that such a source may induce crystal growth of many different structures in several different gel systems, whereas seeds are viewed as being structure specific. They direct the crystallization to only one structure — that of the seed.
KeywordsCrown Ether Natural Zeolite Spontaneous Growth Bronsted Acid Site Zeolite Synthesis
Unable to display preview. Download preview PDF.
- 1.R. M. Barrer, “Hydrothermal Chemistry of Zeolites”, Ch. 4, Academic Press (1982)Google Scholar
- 2.H. Kacirek and H. Lechert, J. Phvs. Chem., 79; 1589 (1975); ibid, 80; 1291 (1976)Google Scholar
- 3.D. E. W. Vaughan, Eur. Pat. App., 0132347 (1985)Google Scholar
- 4.C. H. Elliott, J. and C. V. McDaniel, U. S. Patent 3, 639, 099 (1972)Google Scholar
- 5.D. W. Breck “Zeolite Molecular Sieves”, J. Wiley/Krieger, 58 (1984)Google Scholar
- 6.D. E. W. Vaughan, Mater. Res. Soc. Symp. Ser. III: 89, Ed. M. M. J. Treacy, J. M. Thomas, and J. M. White (1988)Google Scholar
- 8.E. M. Flanigen, R. L. Patton and S. T. Wilson, “Innovation in Zeolite Materials Sciences”, SSSC #37:13, Ed. P. J. Grobet, W. J. Mortier, E. F. Vansant and G. Schultz-Ekloff (1988)Google Scholar
- 9.F. d’Yvoire, Bull. Soc. Chim. France, 1762 (1961)Google Scholar
- 10.E. G. Derouane and R. von Ballmoos, Eur. Pat. Appl. 0146389 (1984)Google Scholar
- 11.M. E. Davis, J. M. Garces, C. H. Saldarriga and MdC. Montes de Correa, Intl. Pat. WO 89 /01912 (1989)Google Scholar