Equilibria for the isomerization of (secondary-alkyl)phenols and cyclohexylphenols

Equilibria of a series of isomerizations and trans-alkylations of alkylphenols have been investigated in the liquid phase over a wide range of temperatures. Equilibria of isomerizations connected with the displacement of a substituent on a benzene nucleus were studied for secondary-butyl-, -amyl-, -hexyl-, and cyclohexyl-phenols, and di-(secondary-butyl)phenols. Equilibria of positional isomerization connected with the displacement of an oxyphenyl radical in an alkyl chain were investigated for oxyphenyl-pentanes, -hexanes, -octanes, and -decanes. Trans-alkylation was investigated for di- and tri-(secondary-butyl)phenols. Values of ΔrHmo and ΔrSmo were found for all investigated reactions. An analysis was made of the thermodynamic quantities for the reactions. Enthalpies of formation of isopropylphenols (ipp) in the gaseous state were calculated. The values of ΔmHmo(kJ·mol−1) were found at 298.15 K: o-ipp, −(175.3±2.4); p-ipp, −(175·3±2.4); m-ipp, −(175.3±2.4); 2,4-di-ipp, −(254.1±2.8); 2,5-di-ipp, −(254.1±2.8); 2,6-di-ipp, −(254.1±2.8); 3,5-di-ipp, −(254.1±2.8); 2,4,6-tri-ipp, −(333.0±3.1).