REACTION IN ION-EXCHANGERS - CHARACTERIZATION OF THE ETHYLENEDIAMINE PROTONATION EQUILIBRIUM IN A SULFONIC MEMBRANE DEVOTED TO CARBON-DIOXIDE FACILITATED TRANSPORT

A method of characterization of the protonation equilibrium of ethylen ediamine (EDA) in a cation-exchange membrane is propounded. This metho d involves an intermediate reaction of the membrane (initially in the mixed EDAH(+)-EDAH(2)(2+) form) with gaseous carbon dioxide then the e lution and the titration of the carbamic acid formed. This method is m ore precise and is preferred to the conversion of the sorbed EDAH(+) a nd EDAH(2)(2+) into EDA by sodium hydroxide followed by an acidic titr ation. The selected method allows to calculate accurately the apparent equilibrium constant K of the protonation of EDA in the membrane and is very useful to characterize the carrier (EDAH(+)) content of membr anes conditioned to achieve facilitated transport of carbon dioxide. T he data obtained will be used in an improved analysis of this transpor t process.