The Viscosities of Aqueous Guanidinium Solutions

Abstract

The viscosities of aqueous guanidinium salt solutions were measured at relatively low concentration at various temperatures. The viscosity B-coefficient of Jones-Dole equation and the activation energies of viscous flow for the guanidinium salt solutions were obtained and shown in Tables 1 and 4. The contribution of guanidinium ion to the activition energy of viscous flow was 20 cal/mol and the B-coefficients of guanidinium ion were O. O^2-8, 0. O^2-2 and O. O^2-9 at 10, 25 and 35° C respectively. However, as shown in Fig.5, these values become negative (-0.077 at 25° C) when the size effect of guanidinium ion, which is evaluated by Einsteins' viscosity equation for large solute particle, is taken into account. This means that the positive value of B-coefficient is mostly due to the contribution of hydrodynamic obstruction effect. Based on the above results, guanidinium ion was concluded to be a structure breaker ion.