Dissociation Constant of N -Methyldiethanolamine in Aqueous Solution at Temperatures from 278 K to 368 K

The chemical equilibrium constant for the dissociation of protonated N -methyldiethanolamine (MDEA, CH 3 N(C 2 H 5 OH) 2 ) in aqueous solutions is determined from electromotive force measurements at temperatures from 278 K to 368 K. Experimental results are reported and compared to literature values. Experimental results (on molality scale) are correlated by ln K = [−819.7/( T /K)] − 79.474 + 10.9756 ln( T /K).