FT-IR and computer modeling study of hydrogen bonding in N-alkyl acrylamide–toluene binary mixtures

Abstract Degree of hydrogen bonding driven self-association of N -( n -butyl)acrylamide, N -( n -octyl)acrylamide, N -( sec -octyl)acrylamide and N -( tert -octyl)acrylamide in toluene was investigated using IR spectroscopy and computer modeling methods. Consistent results were demonstrated in the treatment of the Amide-I (ν C=O ), Amide-II (δ N−H and ν C−N ) and Amide-A (ν N−H ) absorption bands in IR spectra. Thus, the content of non-bonded (free) amide groups decreases from 83–98% to 8–20% and the content of linear polyassociates increases to 80–90% with an increase in monomer concentration from 0.5 wt% to 50 wt%. The content of cyclic dimers was equal to the value between 5 and 10% regardless of the initial monomer concentration. Dependences of the association degree and the content of the linear polyassociates on the concentration were found to be similar for all of the studied amides.