Self-diffusion coefficients of hexamethylphosphoric triamide and ethylene glycol molecules in ethylene glycol solutions

Abstract

The self-diffusion coefficients of the molecules of hexamethylphosphoric triamide (HMPT) and ethylene glycol (EG) in ethylene glycol solutions in the concentration range 0-16 mol % HMPT and molecules of pure HMPT in the temperature range 30–60°С are measured by the spin-echo method on protons. Activation energies for the corresponding processes of self-diffusion were calculated. The obtained data are discussed in terms of solvophobic effects in the EG–HMPT system. The self-diffusion coefficient of pure HMPT was 0.344 × 10⁻⁵ cm²/s at 33.2°C, and the self-diffusion activation energy was 3.86 kcal/mol.