LITHIUM ISOTOPE-SEPARATION BY CHEMICAL-EXCHANGE WITH POLYMER-BOUND AZACROWN COMPOUNDS

The chromatographic separation oflithium isotopes was investigated by chemical exchange with the recently synthesized polymer-bound dibenzo pyridino diamide azacrown (DBPDA) and reduced dibenzo pyridino diamide azacrown (RDBPDA). Column chromatography was employed for the determi nation of the effect of solvents and ligand conformation on the separa tion coefficients. The maximum separation coefficients, epsilon, for t he DBPDA and RDBPDA at 20.0 +/- 0.02 degrees C with acetonitrile as el uent, were found to be 0.034 +/- 0.002 and 0.035 +/- 0.002, respective ly. The isotope separation coefficient and adsorption capability of th e lithium ion on the DBPDA and RDBPDA were only slightly dependent on ligand structure, but strongly dependent on the solvent. DBPDA and RDB PDA appeared to have almost the same value for the isotope separation coefficient of lithium.