Ion size selectivity

A water-soluble sulfonated crown ether (see Figure 80) has been prepared and used as an ion size selection reagent. In the synergistic extraction of alkaline earth ions with 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone and trioctylphosphine oxide in cyclohexane, addition of the sulfonated crown ether shifted the extraction for the larger ions to a higher pH level, thereby improving the... 

Figure 80 The structure of a sulfonated crown ether usable as an ion size selective masking reagent.

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