Thermodynamic properties of aqueous diethanolamine (DEA), N,N-dimethylethanolamine (DMEA), and their chloride salts: apparent molar heat capacities and volumes at temperatures from 283.15 to 328.15 K

Apparent molar heat capacities C-p,C-phi and apparent molar volumes Vg for aqueous diethanolamine (HOC2H4)(2)NH, diethanolammonium chloride (HOC2H4)(2 )NH2Cl, N,N'-dimethylethanolamine (HOC2H4)(CH3)(2)N, and N,N'-dimethylethan olammonium chloride (HOC2H4)(CH3)(2)NHCl were determined from 283.15 to 328 .15 K with a Picker flow microcalorimeter and vibrating tube densimeter. Th e experimental results have been analyzed in terms of Young's Rule with the Guggenheim form of the extended Debye-Huckel equation and appropriate corr ections for chemical relaxation effects. These calculations lead to standar d partial molar heat capacities and volumes for the neutral amines, (HOC2H4 )(2)NH(aq) and (HOC2H4)(CH3)(2)N(aq), and the ions (HOC2H4)(2)NH2+(aq) and (HOC2H4)(CH3)(2)NH+_(aq) over the experimental temperature range.