Synthesis of Alkyl Substituted Dicyclohexano-18-crown-6 Homologues for Strontium Extraction in HNO3 Media

A series of dicyclohexano-18-crown-6 (DCH18C6) homologues containing different alkyl substituents were synthesized for a comparative study of the extraction ability towards strontium. The synthesis and the structure characterization of the intermediates and the products were detailed. The crown ether homologues were labeled as CX-DCH18C6 (X=3∼7), where the X represents the number of the carbon atoms in the alkyl substituents. The extraction ability of the CX-DCH18C6 samples towards strontium in solvent extraction system was investigated. The substituent effect of the samples was discussed, and the factors affecting the separation such as solvent, acidity and initial metal concentration were examined.