Studies on physico-chemical properties with the relaxation phenomena of some normal aliphatic alcohols in non polar solvent under Giga Hertz electric field at a single temperature

Abstract

Double relaxations of some normal aliphatic alcohols have been studied to get relaxation times τ 1 and τ 2 due to rotation of flexible part and end over end rotation of the whole molecule from the intercept and slope of a linear equation of (Χ oij - Χ' ij )/Χ' ij against Χ ij /Χ' ij for different weight fractions wj's of solute in n-heptane at 25 °C under electric field frequencies of 24.33, 9.25 and 3.00 GHz. Alcohols like 1-butanol, 1-hexanol, 1-heptanol and 1-decanol are long straight chain hydrogen bonded polymer type molecules having -OH groups which may bend twist or rotate internally about C-C bond under GHz electric field exhibiting characteristic τ. Estimated τ j obtained from ratio of slopes of individual variation of Χ ij and Χ' ij against w j at w j → 0 are compared with those of Murthy et al., Gopalakrishna (reported data) and τ 1 , τ 2 by double relaxation method. Relative contributions c 1 and c 2 due to τ 1 and τ 2 towards dielectric relaxations estimated from Frohlich's equations are compared with the experimental ones obtained by graphical technique. Graphical variations of Χ' ij /Χ oij and Χ ij /Χ oij with wj at w j =0 together with arbitrary curve of (1/Φ) log (cos Φ) against Φ in degree have been utilised to get symmetric γ and asymmetric δ distribution parameters. The symmetric relaxation time τ s by y and characteristic relaxation time τ cs by δ and Φ are computed to suggest symmetric relaxation behaviour of the molecules. Linear coefficient β's of Χ' ij - wj curves and dimensionless parameters b 1 and b 2 involved with estimated τ 1 and τ 2 are used to get dipole moments μ 1 and μ 2 due to rotation of flexible part and the whole molecule which are compared with reported μ's (Gopalakrishna) and μ theo 's. The slight disagreement between μ j and μ theo obtained from available bond angles and reduced bond moments of substituent polar groups attached to parent molecules arises due to strong internal hydrogen bonds present among the -OH groups of dipolar liquid molecules.