A COMPARISON OF EQUATIONS FOR FITTING PROTONATION CONSTANTS OF CARBOXYLIC-ACIDS IN AQUEOUS TETRAMETHYLAMMONIUM CHLORIDE AT VARIOUS IONIC STRENGTHS

The protonation of acetic, malonic, succinic, citric, 1,2,3-propanetri carboxylic, 2-methyl-1,2,3-propanetricarboxylic, 1,2,3,4-butanetetraca rboxylic, and benzenehexacarboxylic acids was studied potentiometrical ly, at 25 degrees C and at various ionic strengths in aqueous tetramet hylammonium chloride, in the range 0 less than or equal to I-c less th an or equal to 3 mol-dm(-3) (0 less than or equal to I-m less than or equal to 4.4 mol-kg(-1)). Protonation constants were fitted by several equations (Debye-Huckel type, Fitter and Bromley equations) for the d ependence on ionic strength. General equations, containing some common parameters, independent of the acid considered, are reported.