THERMODYNAMICS OF POLY-L-PHENYLALANINE, P OLY-L-METHIONINE AND PROCESSES OF THEIR PREPARATION BY POLYCONDENSATION OF L-PHENYLALANINE AND L-METHIONINE IN THE TEMPERATURE-RANGE FROM 0 TO 350 K

The thermodynamic properties of poly-L-phenylalanine and poly-l-methio nine heat namely capacity C-p(0) in the range of 9 to 340 K and energi es of combustion at 298.15 K, have been studied by the methods of prec ise calorimetry. From the experimental data, the thermodynamic functio ns H-0(T)-H-0(0), S-0(T)-S-0(0), G(0)(T)-G(0)(0) of the polymers for t he temperature range have from 0 to 350 K, enthalpies of combustion De lta H-comb(0), and thermochemical parameters of formation Delta H-f(0) , Delta S-f(0), Delta G(f)(0) at T=298.15 K and p=101.325 kPa have bee n evaluated. The results obtained and the literature data for the corr esponding L-amino acids have been used to calculate the enthalpy, entr opy and the Gibbs function for the processes of poly-L-phenylalanine a nd poly-L-methionine preparation by polycondensation in the temperatur e range of 0 to 350 K. It has been shown that in this temperature rang e, the polycondensation of L-phenylalanine is thermodynamically favour ed and that of L-methionine is hindered.