Chemical reviews online
finally!
Some cages...
...of interesting 8MR zeolites are seen below. These materials have tremendous uses in catalysis, sorption and ion-exchange.
The review features 11 unique tables, comparing data across papers and methods and has been in the making for a long time.
It hopes to inspire other scientists in the field, as well as present a complete story on synthesis and catalysis with small-pore zeolites.
The review focuses only on (Si,Al)O4 compositions, and, of course, 8MR as largest openings.
Below, you can see some of the more exotic 8MR zeolites, i.e. SAS, IHW and ITE. These can be made in Fluoride media with the shown OSDAs.
Read all about it here Chemical Reviews
Small-Pore Zeolites: Synthesis and Catalysis
In the past decade or so, small-pore zeolites have received greater attention than large- and medium-pore molecular sieves that have historically dominated the literature. This is primarily due to the commercialization of two major catalytic processes, NOx exhaust removal and methanol conversion to light olefins, that take advantage of the properties of these materials with smaller apertures. Small-pore zeolites possess pores that are constructed of eight tetrahedral atoms (Si4+and Al3+), each time linked by a shared oxygen These eight-member ring pores (8MR) provide small molecules access to the intracrystalline void space, e.g., to NOx during car exhaust cleaning (NOx removal) or to methanol en route to its conversion into light olefins, while restricting larger molecule entrance and departure that is critical to overall catalyst performance. In total, there are forty-four structurally different small-pore zeolites. Forty-one of these zeolites can be synthesized, and the first synthetic zeolite (KFI, 1948) was in fact a small-pore material. Although the field of 8MR zeolite chemistry has expanded in many directions, the progress in synthesis is framework-specific, leaving insights and generalizations difficult to realize. This review first focuses on the relevant synthesis details of all 8MR zeolites and provides some generalized findings and related insights. Next, catalytic applications where 8MR zeolites either have been commercialized or have dominated investigations are presented, with the aim of providing structure–activity relationships. The review ends with a summary that discusses (i) both synthetic and catalytic progress, (ii) a list of opportunities in the 8MR zeolite field, and (iii) a brief future outlook.