Carboxyl group orientation in K-palmitate/water using 13C double resonance spectroscopy

13C-NMR is used to probe the motion and orientation of the carboxyl group in a 70% potassium palmitate/30% water mixture. An increase in delta sigma with increasing temperature corresponds to a change of orientation of the carboxyl group. Comparison with 2H-NMR and lineshape simulations show that near 57 degrees C the molecules exchange between two orientations at a rate between 10-500 Hz.