Dielectric relaxation studies of N,N-dimethyl formamide and N,N-dimethyl acetamide on complexation with phenols

Dielectric absorption studies of H-bonded complexes of N,N-dimethyl formamide and N,N-dimethyl acetamide with p-cresol, p-chlorophenol, 2,4-dichlorophenol and p-nitrophenol in benzene have been made at 308 K using 9.37 GHz dielectric relaxation set up. The validity of the single frequency equation of Higasi et al. for multiple relaxation time tau((1)) is found to be function of the hydrogen bonding strength of the phenolic hydrogen, whereas the group rotation relaxation time tau((2)) is a function of the steric interactions of the proton donor. The relaxation time is maximum at 50:50 mol% ratio. (C) 2003 Elsevier Science B.V. All rights reserved.