Theoretical Evaluation of Ultrasonic Velocities in Binary Liquid Mixtures of Diethyl Malonate with Branched Alkanols at Different Temperatures
Ultrasonic velocities and densities of the binary liquid mixtures of diethyl malonate with 3- methyl -1- butanol, 2- methyl -1- propanol, 2-propanol and 2-butanol have been measured at temperatures (303.15, 308.15 , 313.15 , and 318.15) K over the entire composition range of ester. The theoretical values of ultrasonic velocity were evaluated using Nomoto relation, Impedance relation, Van Dael and Vangeel relation, Junjie’s relation, Rao’s specific velocity relation, Kudriavtsev relation and Danusso model. The molecular collaboration factor has been assessed from the standards of investigational and theoretical velocities. The variant of this collaboration factor with the composition mixture has been debated in terms of molecular collaborations.
The thermodynamic properties of fluids and fluid mixtures  have been exploited to identify the molecular relations comprising the components of a mixture and also for manufacturing applications relating to the heat transfer, mass transfer and fluid flow. The binary mixtures comprising diethylmalonate and alcohols were favored in the current investigation on the source of their industrial importance. Diethyl malonate (DEM) remains the diethyl ester of malonic acid. DEM is a colourless fluid. The odour of DEM is like that of apple juice. It is utilized in perfumes, preparation of the compounds such as barbiturates, vitamin B1, Vitamin B6 and synthetic flavorings. Alcohols are employed as hydraulic fluids in pharmaceutical and cosmetics, in medications for animals, in manufacturing perfumes, paint removers, flavors and dyestuffs, as defrosting and as antibacterial agents .
Ultrasonic sound velocity of liquid mixtures containing polar as well as non-polar groups are of extensive significance in understanding intermolecular interaction involving constituent molecules [3-8]. Relative studies on the tentative theoretical assessments of ultrasonic velocities for different organic liquid mixtures using different representations resembling Nomoto [9-10], Impedance relation , Van Dael and Vangael , Junjie , Rao’s specific velocity , Kudriavtsev relation  and Danusso model  have been carried out by various researchers. The current study is an extension of our research programme on application of theoretical models of ultrasonic velocities of liquid binaries at various temperatures [17-21].In the current investigation, diethyl malonate is mixed with alcohols at different mole fractions to learn the interactions amongst the fundamental molecules. The results are explained and discussed in terms of molecular interactions present in the investigated systems. The deviation in the variation of U2exp/U2imx, average percentage error, (APE), Chisquare test for goodness of fit, from unity have also been evaluated to further explain the non-ideality of the system. The ratio of U2exp/U2imx gives a suggestion of scope of interaction taking place among molecules of the mixtures, positive values of which support strong interactions among the components.