Partial molar volumes of phenalkylamines and their physiologically active derivatives in water

The partial molar volumes at infinite dilution, V0, for a number of phenalkylamines, their physiologically active derivatives, and their hydrochloride salts have been measured and related to their van der Waals volumes. Results indicate a value of 13.8 mL mol−1 for the electrostriction of water molecules by the terminal [Formula: see text] group. Volumes of proton ionization in these compounds vary between 2.90 and 6.26 mL mol−1.