Electrical properties (permittivity

Electrical properties (permittivity and conductivity) and speed of sound were determined in commercial
vegetable oils from sunflower, corn, soybean, grape, cotton, olive, canola and chia, and in biodiesel from
these oils. Electrical properties were measured in the frequency range from 20 Hz to 2 MHz at temperatures
between 300 K and 343 K. The calibration uncertainty of the measuring system was below 1%.
The speed of sound was determined at the frequencies of 1.53 MHz, 5.66 MHz and 9.43 MHz. The
uncertainty of the results was below 0.05%.
In all the measurements in this work, the temperature of the samples was stabilized within ±0.1 K.
The experimental data for the speed of sound and permittivity of vegetable oils and biodiesel samples
fit very satisfactorily to a linear dependence with temperature, whereas the conductivities follow an
Arrhenius law.
In all the samples, the fitting parameters of the real part of the relative permittivity, the activation
energy of the conductivity and the speed of sound allow to distinguish between the vegetable oil and
the biodiesel obtained from it.
Within the temperature range studied in this work, a linear correlation is found between the speed of
sound and the permittivity of vegetable oils and biodiesel