Prediction of Internal Pressure of Binary Liquid Mixtures Using Flory's Statistical Theory

Internal pressures of a number of binary liquid mixtures of varying natures of component liquids have been predicted using Flory's statistical theory. The predicted values have been compared with the experimentally calculated ones. Good approximation has been observed.

Effect of antioxidant butylated hydroxyl anisole on the thermal or oxidative stability of sunflower oil (Helianthus Annuus) by ultrasonic

The aim of the current investigation was to evaluate the efficiency of butylated hydroxyl anisole (BHA) as an antioxidant in sunflower oil (Helianthus Annuus). The oxidation stability of sunflower oil have been investigated by the effects of varying amounts of BHA. The antioxidant incorporated sunflower oil system and control edible oil were subjected to heating at 180 ± 5 °C continuously for a period of 4 h per day for consecutive 4 days. The parameters used to assess the thermal degradation and oxidation properties of the oils include ultrasonic velocity, viscosity, density and peroxide value. The fatty acid compositions of the oils were measured by gas chromatography. Adiabatic compressibility, intermolecular free length, relaxation time and acoustic impedance have been calculated from experimental data. Viscosity, density and ultrasonic velocity change in control oil is from 3.72 × 10(-2) to 13.2 × 10(-2) Nsm - 2, 918 to 994 kg/m3 and 1412 to 1484 m/s respectively and in sunflower oil with 200 ppm BHA is from 3.88 × 10(-2) to 7.52 × 10(-2) Nsm - 2, 926 to 962 kg/m3 and 1418 to 1463 m/s respectively for 16 h of heat treated oil. The ultrasonic results obtained have shown reduction in thermal degradation and improvement in oxidation stability of antioxidant loaded oil in comparison to base oil. Hence, it can be recommended that sunflower oil with 200 ppm BHA can be used for frying without adverse effect on physical properties. The ultrasonic velocity can be used for assessment of stability of frying oil.

Effect of antioxidant tertiary butyl hydroquinone on the thermal and oxidative stability of sesame oil (sesamum indicum) by ultrasonic studies

The aim of the current investigation is to evaluate the efficiency of tertiary butyl hydroquinone (TBHQ) as an antioxidant in sesame oil (sesamum indicum) by density, viscosity and ultrasonic velocity. The effects of varying amounts of TBHQ on the oxidation stability of sesame oil have been investigated. The antioxidant incorporated sesame oil system and control edible oil were subjected to heating at 180 ± 5 °C continuously for a period of 4 h per day for consecutive 4 days. The parameters used to assess the thermal degradation and oxidation properties of the oils include ultrasonic velocity, viscosity, density and peroxide value. The fatty acid compositions of the oils were measured by gas chromatography. Adiabatic compressibility, intermolecular free length, relaxation time and acoustic impedance have been calculated from experimental data. Viscosity, density and ultrasonic velocity change in control oil is from 3.6553 × 10(-2) to 11.1729 × 10(-2) Nsm(-2), 912.59 to 940.31 kg/m(3) and 1,421 to 1,452 m/s respectively and in sesame oil with 200 ppm TBHQ is from 3.6793 × 10(-2) to 6.4842 × 10(-2) Nsm(-2), 913.78 to 922.45 kg/m(3) and 1,421 to 1,431 m/s respectively for 16 h of heat treated oil. The ultrasonic results obtained have shown reduction in thermal degradation and improvement in oxidation stability of antioxidant loaded oil in comparison to base oil. Hence, it can be recommended that sesame oil with 200 ppm TBHQ can be used for frying without adverse effect on physical properties. The ultrasonic velocity can be used for assessment of stability of frying oil.

Comments on ‘Prediction of internal pressure of binary liquid mixtures using Flory's statistical theory’

A. Ali and M. Tariq ( J. Chem. Res., 30, 2006, 261) have reported the prediction of internal pressure of binary liquid mixtures using Flory's statistical theory. It is now shown that the Ali–Tariq approach to calculate thermal expansion coefficient αp and isothermal compressibility κT for both organic liquids and liquid mixtures, is totally wrong, misleading and introduces errors in thermodynamic data. It should also be emphasised that once the correct expressions for calculating Flory's interaction parameter X12 are known, one should use only those expressions to derive X12 in the prediction of any thermodynamic property of liquid mixtures.