THERMODYNAMIC PARAMETERS OF TRANSFER OF N‐ACETYL ETHYL ESTERS OF DIFFERENT AMINO ACIDS FROM ORGANIC SOLVENTS TO WATER

Abstract

The distribution coefficients of N-acetyl ethyl esters of glycine, diglycine, β-alanine, alanine, valine, norvaline, leucine and norleucine between water and different organic solvents have been measured at different temperatures. Similar distribution coefficients have been measured for simple amides, urea, formamide, acetamide and N-methyl acetamide. From the distribution measurements, ΔG_tr, the free energy of transfer of the solutes from organic solvents to water has been calculated. The temperature dependence of the distribution coefficient values has been utilised to determine the enthalpy of transfer, ΔH_tr, and entropy of transfer ΔS_tr for the above process. From these results similar thermodynamic parameters for the transfer of different nonpolar side chains and peptide groups have been determined and compared with the available data in the literature.