An ab initio study of the selective of alkali and alkaline earth metal cations for crown ethers
- Pacific Northwest National Lab., Richland, WA (United States)
Crown ethers are a class of macrocyclic polyether that are known to preferentially bind certain cations in potentially complex mixtures of other cations. They are being considered as candidates for separating radioactive cesium (137Cs) and strontium (90Sr) from the high level waste tanks on the Hanford Nuclear Reservation. We present the results of RHF and Mp2 calculations on a variety of crown ethers, including 12-crown-4, 18-crown-6 and Clark Still`s 18-crown-6 derivative. Gas phase calculations show that 18-crown-6 most strongly blinds lithium, but our results indicate that potassium selectivity is recovered with the inclusion of even a small number of waters of hydration in the calculations. Several polarized Gaussian basis sets were used in an effort to derive convergence estimates for the binding enthalpies. The only available experimental values, obtained from FT-ICR experiments by A.R. Katritzky, et al, are over 30 kcal/mol smaller than our best estimate for K+/18-crown-6.
- OSTI ID:
- 560091
- Report Number(s):
- CONF-970443--
- Country of Publication:
- United States
- Language:
- English
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