Phase Equilibria in Binary Mixtures of Water with Triglyme and Tetraglyme: Experimental Determination and Thermodynamic Modeling was written by Kolin, Ondrej;Dohnal, Vladimir. And the article was included in Journal of Chemical & Engineering Data in 2020.Formula: C8H18O4 This article mentions the following:
Because of their many favorable properties and specifically balanced amphiphilic nature, glymes (oligomeric ethylene glycol diethers) are of great technol. and theor. interest. This study focuses on the phase equilibrium and energetics of aqueous solutions of two important members of the glyme series, triglyme (triethylene glycol di-Me ether) and tetraglyme (tetraethylene glycol di-Me ether). For these systems, we carried out accurate measurements of water activity at two temperatures (298.15 and 313.15 or 318.15 K) in the whole composition range, boiling temperatures at three pressures (50, 70, and 90 kPa), and freezing temperatures in the water-rich region. The melting temperature and melting enthalpy of the neat glymes were also determined We correlated our water activity data simultaneously with some related thermal data from the literature using an extended SSF-type excess Gibbs energy (GE) model. The established model descriptions provided not only particularly good fit of the underlying data but, as proven by due comparisons to other results from both the literature and this work, showed a superior performance, extrapolating very well to both higher and lower temperatures The high-fidelity global modeling also enabled us to present a clear picture of the energetics of the two aqueous glymes. At near-ambient temperatures, both systems exhibit non-monotonous activity coefficient courses with composition, large exothermic effects, and remarkably deep drops of the entropy accompanying the mixing, their pos. GE being entropy-driven. On increasing the temperature, the former features gradually decline while GE keeps about the same magnitude and becomes enthalpy-driven. Although both systems show a great tendency to phase splitting above the normal boiling temperature of water, our model calculations predicted the lower critical solution temperature behavior only for the aqueous solution of triglyme. The observed pattern of the energetic behavior has been well elucidated in terms of competitive water-water and water-ether H-bonding. In the experiment, the researchers used many compounds, for example, 2,5,8,11-Tetraoxadodecane (cas: 112-49-2Formula: C8H18O4).
2,5,8,11-Tetraoxadodecane (cas: 112-49-2) belongs to ethers. Of all the functional groups, ethers are the least reactive ones. Ether bonds are quite stable towards bases, oxidizing agents and reducing agents. But on the other hand, ethers undergo cleavage by reaction with acids. Autoxidation is the spontaneous oxidation of a compound in air. In the presence of oxygen, ethers slowly autoxidize to form hydroperoxides and dialkyl peroxides. If concentrated or heated, these peroxides may explode. To prevent such explosions, ethers should be obtained in small quantities, kept in tightly sealed containers, and used promptly.Formula: C8H18O4
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem