Abstract: Densities of glycine, L-alanine and L-serine in 2-chloroethanol-water mixed solvents have been measured at 298.15 K by an oscillating-tube densimeter. Apparent molar volumes, limiting partial molar volumes, transfer partial volumes, hydration numbers and volumetric interaction coefficients for these amino acids have been calculated. The results show that all of the transfer partial volumes from water to 2-chloroethanol-water mixed solvents are positive, and increase with increasing 2-chloroethanol concentration; all the hydration numbers decrease with increasing 2-chloroethanol concentration. From the results of the volumetric interaction coefficients, it is concluded that interaction between glycine and 2-chloroethanol is dominated by 1 : 1 and 1 : 2 forms, and interactions between alanine, serine and 2-chloroethanol molecule are dominated by 1 : 1 form.

Key words: Glycine, Alanine, Serine, 2-Chloroethanol, Partial molar volumes