Chain conformation of aliphatic alpha,omega-diamines in aqueous solutions

Potentiometric titration of aliphatic alpha,omega-diamines such as 1,3-, 1, 3-, and 1,6-diamines was carried out in aqueous solutions with and without added salt to study the effect of electrostatic interactions on the chain c onformations. The ratios of first to second association constants of proton K-1/K-2 were larger than 4 indicating the effects of electrostatic interac tions on the second association constant in a similar manner as alpha,omega -diacids. These data were analyzed by the theories of Bjerrum and Kirkwood- Westheimer, and the resulting charge distances were compared with the end-t o-end distances of various chain models.