Interaction between phenol and electron donors in cyclohexane and carbon tetrachloride
Abstract
Association constants, kc, for the process phenol + electron donor ⇌ complex have been determined from absorbance measurements at a predetermined wavelength in the u.v. region for a series of solutions of phenol in cyclohexane–donor and carbon tetrachloride–donor mixtures of varying composition. Electron donors used are classified as ether- or alcohol-type and consist of 1,2-dimethoxyethane, tetrahydrofuran, dioxan, diethyl ether, di-isopropyl ether, di-n-butyl ether, methanol, ethanol, n-butanol, propan-2-ol, isoamyl alcohol, t-butyl alcohol, and dimethylformamide. It is found that (i)Kc is greater in cyclohexane than in carbon tetrachloride solution, (ii)Kc increases with increase in donor ET value, and in the case of the ethers with ΔνD the shift in the O–D stretching frequency of methan[2H]ol, defined as νD(benzene)–νD(ether), and (iii) variation in Kc arises principally from changes in the standard entropy of association, ΔS⊖.