Variable-temperature 13C NMR spectroscopy is used to investigate barrier of C-N internal rotation in compound 4-(Phenyl) acetyl morpholine, and then with simulation of band shape broadening pattern at coalescence region, rate constants of exchange were obtained for all temperatures. For simulation of line-shape broadening Spin works software (version 3.1) was used, that with two interfaces made possible simulation with two band shape simulator programs, Dynamic Nuclear Magnetic Resonance (DNMR) and MEXICO. For obtaining the thermodynamic activation parameters Gaussian 98 program was used, resulting Delta G(298)(#) G toluene is 68.09 kJ/mol. (C) 2013 The Authors. Published by Elsevier B.V.