High pressure solubility data of carbon dioxide in (tri-iso-butyl(methyl)phosphonium tosylate + water) systems

Ionic liquids are attracting great attention nowadays due to their interesting properties which make them useful in a broad range of applications including reaction media or separation/capture of environmentally hazardous gases such as carbon dioxide. In many cases, for practical and/or economical reasons, the use of aqueous solutions of ILs would be preferable to their use as pure compounds. In this work, high pressure equilibrium data for the {carbon dioxide (CO2) + tri-iso-butyl(methyl)phosphonium tosylate [iBu3MeP][TOS] + water system were measured at temperatures ranging from (276 to 370) K and pressures up to 100 MPa. Measurements were performed using a high-pressure cell with a sapphire window that allows direct observation of the liquid–vapour transition. Mixtures with different IL concentrations were studied in order to check the influence of the amount of IL on the solubility of CO2 in the aqueous mixture. The results show that the presence of IL enhances the solubility of CO2 in the (IL + water) system revealing a salting-in effect of the IL on the solubility of CO2. The appearance of a three phase region was observed for IL concentrations higher than 4 mol% of IL in water when working at pressures between 4 and 8 MPa and temperatures between (280 and 305) K. In this range, the upper limit of the VLE region observed is shown to increase with the temperature being almost independent of the IL initial concentration in the mixture.Fundação para a Ciência e a Tecnologia (FCT)FEDERCICECO, University of Aveir

Experimental Densities and Speeds of Sound of Substituted Phenols and Their Modeling with the Prigogine-Flory-Patterson Model

This work provides new experimental data of speed of sound and density for seven pure components of pyrolysis bio-oil at atmospheric pressure for several phenols (phenol, o-, m-, and p-cresol), two phenolic ethers (2-methoxyphenol and eugenol) and one phenolic ester (methyl salicylate) at temperatures of (288.15 to 343.15) K. Densities and sound velocities are correlated with the Prigogine-Flory-Patterson (PFP) model. The properties are well described with the PFP model showing a better performance for the denser substances. The relation between density and speed of sound evidence the complex thermophysical behavior of substituted phenols

Novel data and a group contribution method for the prediction of the speed of sound and isentropic compressibility of pure fatty acids methyl and ethyl esters

Speed of sound of fatty acid esters are relevant for the formulation of biodiesel fuels but data on this property are scarce on literature. In this work speeds of sound of three saturated fatty acid methyl esters (caprate, myristate, palmitate) two unsaturated (oleate, linoleate) as well as two fatty acid ethyl esters (caprate, myristate) were measured using a pulse echo technique operating at 3 MHz. The measurements were carried out at atmospheric pressure in the temperature range 283.15-373.15 K. Additional density measurements were performed in order to estimate the isentropic compressibility and the molecular compressibility. From these data, a group contribution method was developed to predict the molecular compressibility and speed of sound of both methyl and ethyl esters with an uncertainty of circa 0.1%. (C) 2012 Elsevier Ltd. All rights reserved

An atomic contribution model for the prediction of speed of sound

Speed of sound is an important property in many applications and it is being increasingly used in different technological areas. In this work a database of speed of sound and density at atmospheric pressure for n-alkanes, branched alkanes, n-alkenes, aromatics, alcohols, ethers and esters were collected from the open literature. Using these data a Wada group contribution model recently proposed by us was used as the basis for the development of a new atomic contribution model to predict speed of sound for all the families of compounds investigated in this work. It is shown that the proposed model is able to predict the speed of sound for compounds of these families with deviations close to the experimental reproducibility. This work also discusses the effect of branching on the Wada's constant, pointing out the importance of new measurements for this type of compounds. (C) 2013 Elsevier B.V. All rights reserved

Speed of Sound, Density, and Derivative Properties of Methyl Oleate and Methyl Linoleate under High Pressure

Speeds of sound were measured for methyl oleate and methyl linoleate (C15H30O2) at pressures up to 200 MPa along isotherms ranging from (283.15 to 393.15) K. Additional density measurements were carried out by using a U-tube densimeter up to 100 MPa from (293 to 393) K. From the integration of speed of sound, density was evaluated up to 200 MPa, and the isentropic compressibility was determined in the same p-T domain. A correlation that represents both the density and the speed of sound within their experimental uncertainties is reported to evaluate both the volume and its derivatives with respect to pressure (isothermal compressibility) and temperature (isobaric expansion)

Speed of Sound, Density, and Derivative Properties of Ethyl Myristate, Methyl Myristate, and Methyl Palmitate under High Pressure

Speeds of sound have been measured in ethyl myristate (C16H32O2), methyl myristate (C15H30O2), and methyl palmitate (C17H34O2) at pressures up to 100 MPa along isotherms ranging from (293.15 to 403.15) K. The measurements were carried out using a pulse echo technique operating at 3 MHz. Additional compressed liquid density measurements were performed from (293.15 to 393.15) K with pressures from (0.1 to 100) MPa in order to evaluate isentropic compressibility using speed of sound measurements. An equation of state that represents both the density and the speed of sound temperature reported experimental data within their estimated uncertainties is given to evaluate the volume as well as its derivatives of these components

Measurement and prediction of the speed of sound of biodiesel fuels

Speed of sound is an important fuel thermophysical property that directly characterizes the fuel injection and the NOx emissions in diesel engines especially for injectors activated with pressure. Nevertheless, the experimental data of speed of sound for biodiesel fuels are very scarce in the literature. Thereby, this work aims at measuring the speed of sound for biodiesels fuels and evaluating some predictive models to estimate the speed of sound from the composition of fatty acid methyl esters in the biodiesel. For that purpose the measurement of speeds of sound for three fatty acid methyl esters and ten biodiesel fuels at atmospheric pressure and temperatures from 288.15 to 343.15 K was done. The ability of two versions of Auerbach's relation, and the ideal mixture mixing rule to describe the speed of sound of biodiesels was evaluated. The results evinced that, with the exception to the original version of Auerbach's relation, the other models studied provide a good estimate of the experimental data. The modified Auerbach's relation displays an overall average relative deviation of 1.64%, and the ideal mixture mixing rules predict the biodiesel speed of sound with only 0.37% of overall deviation. Moreover, the dependency of speed of sound on pressure was also correlated with a linear equation, presenting only an overall deviation of 0.56%. These models can thus be a good tool to estimate the speeds of sound using only information about the biodiesel composition. (C) 2012 Elsevier Ltd. All rights reserved

Thermal conductivity of heavy, even-carbon number n-alkanes (C22 to C32)

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