A Raman spectroscopic study of molecular interaction in long‐chain primary amines systems

The NH, CH and CC stretching regions at 3100‐3400 cm −1 , 2800‐3000 cm −1 and 1000‐1150 cm −1 , respectively, and the low‐frequency accordion‐like vibration region, have been investigated by Raman spectroscopy for the octyl‐, nonyl‐, dodecyl‐, tetradecyl‐ and hexadecyl‐normal primary amines series, at different temperatures and for different physical states. The spectra were interpreted in terms of structural changes, particularly of the conformations of the paraffin chains, the chain length and the physical state. The changes in the NH region were associated mainly with molecular association, whereas the changes in the other spectral regions studied were associated mainly with the molecular packing of the chains.