Extraktion von Alkali‐ und Erdalkalimetallpikraten aus wässerigen Lösungen in Methylenchlorid durch ungeladene azyklische Ionophoren. Quantitative Interpretation

Abstract

Extraction of alkali and alkaline earth metal picrates from water into methylene chloride. Quantitative interpretation The ligands N, N, N′, N′ ‐tetraphenyl‐3, 6‐dioxaoctanediamide (1) , (−)‐( R, R )‐ N, N′ di [(ll ‐ ethoxycarbonyl) undecyl] ‐ N, N′ , 4, 5‐tetramethyl‐3, 6‐dioxaoctanediamide (2) , and N, N′ ‐diheptyl‐ N, N′ , 5,5‐tetramethyl‐3,7‐dioxanonanediamide (3) , reported earlier as components for liquid membrane electodes with selectivity for Ba 2+ (1) , Ca 2+ (2) and Li + (3) , were used to study models for the extraction of alkali and alkaline earth metal picrates from water into methylene chloride. The composition of the extracted complexes of alkaline earth cations with 1 and 2 proved to be mono‐ and diassociated with the picrate anion. The extraction selectivity observed for 1, 2 , and 3 towards different cations paralleled the potentiometric selectivity factors obtained for liquid membrane electrodes with 1, 2 , and 3 as membrane components.