Enrichment of Potassium Isotopes with Macrocyclic Polyether Potassium Complexes

Enrichment of the potassium isotopes is achieved by means of the chemical exchange reaction \documentclass{article}\pagestyle{empty}\begin{document}$$ ^{41} {\rm K}^{\rm + } + ^{39} {\rm KL}^{\rm + } \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\longrightarrow\over{\smash{\longleftarrow}\vphantom{_{\vbox to.5ex{\vss}}}$}} ^{39} {\rm K}^{\rm + } + ^{41} {\rm KL}^{\rm + } $$\end{document} Where L represents a macrocyclic polyether. Dicyclohexyl‐18‐crown‐6 ((cis‐syn‐cis)‐isomer) was investigated. The single stage‐separation factor a=1+ε was determined according to the method of Glueckauf from the elution curve and iso‐topic assays. One obtains ε‐values of 1.18, 0.84. and 0.74 × 10−3(±5×10−5) at −10, 0 and 10° respectively, in favor of the heavy isotope, indicating an enthalpy of isotopic exchange of −13 ± 4 Joule mol−1. The technical feasibility of a pre‐enrichment process for 40K starling with basic laboratory data is discussed.