IIn this short communication, we revise a correlation for the saturated liquid isothermal compressibility based on the data available in DIPPR (Postnikov, 2016) which considers the molecular non-sphericity and addresses a problem of predicting speeds of sound in saturated long-chained alkanes. In addition, we correct a misprint appeared in the cited work and provide programming code used for the realisation of the proposed calculations.
The paper analyses a possibility of utilising the information which is contained in DIPPR database for a calculation of the speed of sound, which is absent there. As an example, liquid hydrocarbons are considered: n-hexane, 1-hexene, cyclohexane, cyclohexene, benzene, and 1-hexanols, as well as representatives of n-alkanes with various hydrocarbon chain lengths. It is shown that the Brelvi-O’Connell correlation for the reduced bulk modulus, supplied with the correlations for the internal pressure at the normal boiling temperature, results in the values having accuracy comparable with other DIPPR data for the region below the boiling point bounded by the values of the reduced density around ρr ≈ 3.5. The source of errors originated from the Brelvi-O’Connell correlation for larger reduced densities is discussed.
An emerging ultrasonic technology aims to control high-pressure industrial processes that use liquids at pressures up to 800 MPa. To control these processes it is necessary to know precisely physicochemical properties of the processed liquid (e.g., Camelina sativa oil) in the high-pressure range. In recent years, Camelina sativa oil gained a significant interest in food and biofuel industries. Unfortunately, only a very few data characterizing the high-pressure behavior of Camelina sativa oil is available. The aim of this paper is to investigate high pressure physicochemical properties of liquids on the example of Camelina sativa oil, using efficient ultrasonic techniques, i.e., speed of sound measurements supported by parallel measurements of density. It is worth noting that conventional low-pressure methods of measuring physicochemical properties of liquids fail at high pressures. The time of flight (TOF) between the two selected ultrasonic impulses was evaluated with a cross-correlation method. TOF measurements enabled for determination of the speed of sound with very high precision (of the order of picoseconds). Ultrasonic velocity and density measurements were performed for pressures 0.1–660 MPa, and temperatures 3–30XC. Isotherms of acoustic impedance Za, surface tension σ and thermal conductivity k were subsequently evaluated. These physicochemical parameters of Camelina sativa oil are mainly influenced by changes in the pressure p, i.e., they increase about two times when the pressure increases from atmospheric pressure (0.1 MPa) to 660 MPa at 30XC. The results obtained in this study are novel and can be applied in food, and chemical industries.