A perspective on zeolite synthesis: How do you know what you`ll get?
- California Institute of Technology, Pasadena, CA (United States)
- Chevron Research & Technology, Richmond, CA (United States)
Zeolites are an important class of compounds for mant reactions involving hydrocarbons, such as, for example, the preparation of synfuels.In this paper we consider some of the emerging guidelines in zeolite preparation. Generally, the history of these syntheses has shown an inverse relationship for OH/SiO{sub 2} and SiO{sub 2}/Al{sub 2}O{sub 3}. With a exceptions (to be discussed), these parameters even establish some discreet regions in silicate zeolite products. At high OH, trends are: (1) Large pore, low density zeolites; (2) Small pores with sizable cavities and also low densities; (3) 4-ring and 6-ring subunit construction; and (4) Intermediate pore and 5-ring subunits missing. At low OH/SiO{sub 2} leading to high SiO{sub 2}/Al{sub 2}O{sub 3} virtually all of the above properties are excluded yielding: (1) Mostly 5-ring construction; (2) Clathrasils compete as products; (3) Nonintersecting channel systems become favorable and (4) Products without organic guests become excluded. To introduce further complexity, we can overlay onto the above issues kinetic factors affecting nucleation selectivity. Still, with all these issues considered, it is possible to design guest molecules to achieve synthesis objectives. In this regard, we will also consider the emerging, exciting aspects of zincosilicate and borosilicate influences on phase selectivity, as well as the issues of short and long-range order in crystal growth.
- OSTI ID:
- 126754
- Report Number(s):
- CONF-950402-; TRN: 95:006086-0777
- Resource Relation:
- Conference: 209. American Chemical Society (ACS) national meeting, Anaheim, CA (United States), 2-6 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of 209th ACS national meeting; PB: 2088 p.
- Country of Publication:
- United States
- Language:
- English
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