CONDUCTIVITY OF SOME TETRA-N-ALKYLAMMONIUM SALTS OF PECTIC ACID

From commercially available pectin, (OBIPEKTIN AG), pectic acid was is olated by alkaline catalysed hydrolysis and physicochemically characte rized. The conductivities of aqueous solutions of tetramethyl-, tetrae thyl-, tetra-n-propyl- and tetra-n-butyl pectate were determined. The concentration dependence of the conductivity as well as the conductome tric titration of the investigated systems exhibited typical polyelect rolyte behaviour. The mobility of the polyelectrolyte solute was found to be influenced by the nature of the counterion. The calculated valu es of the molar conductivity deduced on the basis of the Manning limit ing law were found to be lower than the experimental ones. The fractio n of free counterions was evaluated and found to depend on the concent ration and on the nature of the counterion. (C) 1997 Elsevier Science Ltd.