GAS-LIQUID CHROMATOGRAPHIC STUDY OF ORTHO-EFFECT OF PHENOLS

The specific retention volumes have been measured for a series of ortho-, meta- and para-phenols and anisoles in a wide range of solvents using gas-liquid chromatography. From these, specific retention volume ratios, activity coefficient ratios, heats and entropics of solutions have been calculated. A. The specific retention volume and activity coefficient ratios show the order of strength of intramolecular hydrogen bonding in ortho-substituted phenols. B. The heats and entropies of solution are proven to follow a linear relation for each series. The heats can be understood in terms of the physical forces of solution and the interactions between ortho-substituted groups. C. Disagreement in the literature over the strengths of the intramolecular hydrogen bonding in ortho-halogenated phenols is resolved by the gas chromatographic measurements. The solvents can be divided into two groups depending upon their ability to break or not to break the intramolecular hydrogen bonding in ortho-phenols. © 1978 Oxford University Press.