Investigation of dielectric relaxation in tributyl phosphate from susceptibility and conductivity measurement under microwave field

Susceptibility (chi (ij)'s) and conductivity (sigma (ij)'s) measurement techniques are proposed to determine dielectric behaviour in terms of relaxation time tau and dipole moment mu of tributyl phosphate (TBP, j) dissolved in various non-polar solvent (i) (p-xylene, cyclohexane and n-heptane) under S-band, C-band, X-band and Ku-band microwave field at different temperatures (25, 30 and 35 degrees C) within Debye's dielectric model. The possibility of double relaxation times (tau (2) and tau (1)) for inter- and intra-molecular rotation of the polar molecule TBP is predicted from measured data of chi ij '</mml:msubsup> (= epsilon ij '-epsilon (infinity ij)), chi ij '' (= epsilon ij '') and chi (0ij) (= epsilon (0ij) - epsilon (infinity ij)) at different weight fractions w(j)'s of solute, applying slope and intercept of <mml:mfrac><mml:msub>chi 0ij-chi ij ' chi ij '</mml:mfrac> against <mml:mfenced close=")" open="("><mml:mfrac>chi ij '' chi ij '</mml:mfrac></mml:mfenced> linear equation to confirm mono relaxation behaviour tau (2) only. tau 's are measured from individual variation of real and imaginary parts of chi (ij) and sigma (ij) with w(j)'s as well as linear relation of imaginary against real. The dipole moments mu (j)'s are measured from both the measurement techniques under S-band (3.2 GHz), C-band (6.8 GHz), X-band (11.2 GHz) and Ku-band (16.5 GHz) microwave field at 25, 30 and 35 degrees C temperatures. Various molecular associations are determined in terms of relaxation time tau and dipole moment mu in polar-non-polar liquid mixture. Thermodynamic energy parameters are also calculated from Eyring rate theory to predict molecular dynamics or nature of molecular environment surrounding the polar molecule TBP. Debye relaxation mechanism in all the systems under observation is validated by the estimated Debye factor from both the measurement methods. A new simple microwave sensor is proposed to design for determination of TBP concentration from measured penetration depth at different temperatures under microwave field.