Transfer activity coefficients between some dipolar aprotic solvents and alcohols of salts composed of various anions and potassium complexed with Bis(4,4'(5')-t-butylbenzo)-18-crown-6

Abstract

Stability constants, K^f(LK⁺) and K^f(LKX) = [LKX]/[L][KX] at 25º in the dipolar aprotic solvents acetone (Me₂CO), acetonitrile (MeCN), propylene carbonate (pc), N,N-dimethylformamide (HCONMe₂), dimethyl sulfoxide (Me₂SO), as well as in the alcohols, methanol (MeOH), isopropyl alcohol (Pr¹OH), and butan -1-ol (BuOH) have been determined, L being bis(4,4'(5')-t-buty1benzo)-18- crown-6 (di(BuBo)-18-cr-6). This crown is considerably more lipophylic than is dibenzo-18-crown-6. Values of K^f(LKX) have been found from values of K^f(LK⁺), KA(KX) and KA(LKX). Transfer activity coefficients, ^Me2^COγ^S, have been calculated (based on the Parker proposal that γ(Ph₄As⁺) = γ(BPh₄-) between acetone and the various solvents used of K⁺, Br^-, ClO₄^-, P1^- (picrate), LK⁺, KX, and LKX. It is found that K⁺ is more strongly solvated in Me₂CO than in the other aprotic solvents of low donicity. The reverse is true between Me₂CO and HCONMe₂ or Me₂SO (even after correcting for the Born effect).