NMR study of hydrogen bonding association of some sterically hindered alcohols in carbon tetrachloride, chloroform and cyclohexane

The self-association (dimerization) due to hydrogen bonding for some alcohols with bulky side chains was investigated by nuclear magnetic resonance spectroscopy. The systems studied include 2,4-dimethyl-3-pentanol or 3-methyl-3-pentanol in [H-2(12)]cyclohexane, carbon tetrachloride or [H-2(1)]chloroform, and 2,3,4-trimethyl-3-pentanol in carbon tetrachloride. The dilution shift data of hydroxyl proton were measured and employed to deduce the monomer shift, dimer shift and dimerization constant with the help of a graphic method. Use of van't Hoff plot for dimerization constants thus obtained at different temperature gave the enthalpy and entropy of dimerization. Also discussed herein is the effect of substituent hindrance and dielectric constant of solvent on the self-association.