Extraction of copper with p‐tert‐butyl‐calixarenes

The extraction of copper with calixarenes was researched by comparing the results from calix[4]-, calix[6]- and calix[8]-arenes. The extraction ability increased as the order: calix [4]⇛ calix[8]⇛ calix[6]-arenes, with the binding ratio being 1:1. The extraction mechanism was also discussed, and its equation Cu(NH3)42+ +H2L(0)KexCu(NH3)4L(0) +2H+ and the extraction equilbrium constants (Kex) for calix[6]- and calix[8]-arenes were obtained respectively.