It is observed from Tables that the o and geff

It is observed from Tables 1–6 that, the εo, ε∞, τ, and geff values of alcohols with amides mixtures (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90%) lie between the individual values of pure alcohol and amides. This result indicates the existence of molecular association between the alcohol and amide molecules. Similar results were reported by (Kroeger (1987) and Ritzoulis and Fidantsi (2000) for DMA-alcohol mixtures. The values of εo, ε∞, τ, and geff increases as the percentage of alcohol in amides increases for all the systems. This suggests that the intermolecular association is taking place in all these systems. Similar results were reported by Khirade et al. (1999a), for DMF-alcohol mixtures. It can be seen from Tables 1–6 that, the values of εo and ε∞ for pure alcohol and amides and binary mixtures of alcohols with amides are in the order: 1-butanol > 1-pentanol > 1-hexanol > 1-heptanol > 1-octanol > 1-decanol for concentrations studied. This trend can be ascribed to the decrease of dipoles per unit volume with an increase in the size of the alcohol molecules. This observed result is in close agreement with the investigation of Patil et al. (1999), for aniline with ethanol, 1-propanol, 1-butanol, 1-hexanol and 1-heptanol systems. Further, they have reported that the decreasing trend of εo and ε∞ values can be attributed to decrease in the number of dipoles in the mixture, which may lead to the decrease in the molar volume of the rotated molecule. It is observed from Tables 1–6 that, the values of τ for pure alcohols and amides and binary mixtures of various alcohol with amides increase in the order: <1-butanol < 1-pentanol < 1-hexanol < 1-heptanol < 1-octanol < 1-decanol. This indicates that the higher alkyl chain length of alcohols hinders the rotation of the molecule which leads to increasing relaxation time is noticed. This may be linearly correlated with the variations of viscosity and molecular size of the alcohols. From this result, it AEBSF may be concluded that the strength of hydrogen bonding is linearly increases with chain length of alcohols. Similar conclusions were drawn by Balamurugan et al. (2005), for triethylamine and pyridine with alcohol (1-hexanol, 1-heptanol and 1-octanol) systems. The alcohols with NMA have higher τ values than the DMA. This may be due the variation of inductive effect in secondary and tertiary amides. Similar results were reported by Kalaivani et al. (2005), for NMA and DMA with acetonenitrile systems. The information about the solute–solvent interaction is also given by the Bruggeman factor. The effective volume of the solute gets modified by solute–solvent interactions and is best illustrated by the non-linearity of the Bruggeman formula (Bruggeman, 1935). The Bruggeman factor may be used as an indicator of solute-solvent interaction. The Bruggeman plots of volume fraction of alcohol Vs Bruggemann factor (FBM) for alcohols-amides mixtures are given in Fig. 1. It can be seen from these figures cell cycle FBM is not a linear function of volume fraction of alcohol. The observed results indicate the existence of an intermolecular association between OH group of alcohol and CO group of amide. Similar interpretations are given by Rana and Vyas (2002b) for aniline with alcohols. The excess parameters related to ε0 and τ provides valuable information regarding interaction between the polar-polar liquid mixtures. These properties are also useful for detection of the cooperative domain in the mixture and may evidence the formation of multimers in the mixture due to intermolecular association. The structural information about the liquids from the dielectric relaxation parameter may be obtained using the Kirkwood correlation parameter g (Kirkwood, 1939). This factor is also a parameter for obtaining information regarding orientation of electric dipoles in polar liquids. The g for the pure liquid may be obtained using the expressionwhere μ is the dipole moment in the gas phase, ρ is the density at temperature T, M is the molecular weight, k is the Boltzmann constant, and N is Avogadro\'s number.