Apparent molar volumes and viscosities of some alpha-amino acids in aqueous sodium butyrate solutions at 298.15 K

Densities and viscosities of aqueous solutions of alpha -amino acids (glyci ne, DL-alanine, DL-alpha -amino-n-butyric acid, DL-alpha -valine, and DL-al pha -leucine), + sodium butyrate have been measured as a function of concen trations of amino acid and electrolyte at 298.15 K. These data have been us ed to calculate apparent molar volumes and viscosity B-coefficients of the amino acids. The standard partial molar volumes, V degrees (2,Phi), standar d volumes of transfer, Delta V-t degrees and hydration-numbers of the amino acids have been determined. It has been shown and hydration-numbers of the amino acids have been determined. It has been shown that V degrees (2,Phi) , Delta V-t degrees and the B-coefficient vary linearly with increasing num ber of carbon atoms in the alkyl chain of the amino acids, and they were sp lit into contributions from the charged end group (NH3+, COO-) and CH2 grou ps of the amino acids. From the volumetric data, we found that sodium butyr ate interacts strongly with the charged center of the zwitterion of the ami no acids and has a strong dehydration effect on the amino acids.