The thermodynamic dissociation constants of four diastereoisomeric pairs of 1 : 2-disubstituted succinic acids have been measured (in water at 25") by a combination of conductometric and potentiometric procedures. The results do not confirm the apparent trend which could be observed in the earlier classical data, viz., that the meso-acid is consistently weaker than the racemic acid.

24-05 461. Chemical Cmtitution and the Dissociation Constants of Monocurboxylic Acib. Part X VII.* ortho-E'ects in Substituted Salicylic Acids.

Conductances in ethyl methyl ketone a t 25" are reported for a series of quaternary alkylammonium salts including the tetra-n-alkylammonium iodides and bromides from methyl up to n-octyl. Single-ion conductances have been evaluated by use of n-butyltri-isopentylammonium tetraphenylboride as the reference electrolyte. Hydrodynamic radii give no evidence of solvation of the cations while association parameters indicate anion penetration of the cations in association.

Two earlier papers (J., 1941, 550; 1944, 411), which appeared under specific titles, are regarded as Parts XI and XI1 of this series.

No abstract