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Inhibition of Dimerization of Copper(II) Carboxylates by Cyclohexane Ring in Extraction of Copper(II) with Cyclohexanecarboxylic Acid

1987; Oxford University Press; Volume: 60; Issue: 10 Linguagem: Inglês

10.1246/bcsj.60.3557

1348-0634

Hiromichi Yamada, Miyuki It o, Masateru Mizuta,

Radioactive element chemistry and processing

Abstract The extraction of copper(II) with cyclohexanecarboxylic acid in benzene was carried out at 25 °C and at the aqueous ionic strength of 0.1 mol dm−3 (NaClO4). The partition constant, KD,HA of cyclohexanecarboxylic acid between benzene and water, and the dimerization constant, K2,HA of cyclohexanecarboxylic acid in benzene were determined: logKD,HA=0.90 and logK2,HA=1.54, respectively. The monomeric and dimeric copper(II) cyclohexanecarboxylates were responsible for the extraction: Cu2++(HA)2,o \ightleftharpoons (CuA2)o+2H+ Cu2++2(HA)2,o \ightleftharpoons (CuA2(HA)2)o+2H+ 2Cu2++2(HA)2,o \ightleftharpoons (Cu2A4)o+4H+ 2Cu2++3(HA)2,o \ightleftharpoons (Cu2A4(HA)2)o+4H+ with the extraction constants, logKex(10)=−8.34, logKex(12)=−7.33, logKex(20)=−12.47, and logKex(22)=−11.73, respectively. By comparing the overall formation constant of the dimeric copper(II) cyclohexanecarboxylate, Cu2A4(HA)2 in the aqueous phase with that of copper(II) decanoate and lipoate, the cyclohexane ring was found to inhibit the formation of the dimeric copper(II) carboxylate.