EFFECT OF THE ADDITION OF ELECTROLYTES ON THE PARTITION-COEFFICIENTS,ACTIVITY-COEFFICIENTS, AND ACID DISSOCIATION-CONSTANTS OF CARNITINE AND ITS ACETYL AND PROPIONYL DERIVATIVES

The partition coefficients, P, between n-octanol and water of carnitin e, acetylcarnitine, propionylcarnitine, and tetraethylammonium pentacy anopropenides have been determined spectrophotometrically at 20 degree s C, The value of P increases upon addition of electrolytes, the incre ase produced by LiCl being particularly high. The carnitine cations ar e 'salted-out' by electrolytes as shown by the variation of their 'sin gle ion' activity coefficients (relative to that of the tetraethylammo nium ion) with electrolyte concentration. These cations are appreciabl y more hydrated than the reference tetraethylammonium ion. The conside red carnitine cations are at least one pK(a)(where K-a is the acid dis sociation constant) unit more acidic than butanoic acid in water at 25 degrees C, Electrolyte addition somewhat increases the pK(a) of these cationic acids.