The Dipole Moments of the Oligether of Ethylene Glycol

Abstract

The dipole moments of ethylene glycol dimethyl ether (N=1), diethylene glycol dimethyl ether (N=2), triethylene glycol dimethyl ether (N=3), and tetraethylene glycol dimethyl ether calculated on the assumptions that: (i) the dipole moments of these chain molecules are given by the vector sum of the polar groups of ether whose group moment is 1.20 D, and (ii) all the internal rotations of a chain molecule are free. The calculated values of N= 1, N= 2, N=3, and N=4 are 1.67D, 2.03D, 2.33D, and 2.60D, respectively. The agreement between the observed and the calculated values is satisfactory. The solvent effect and the temperature dependence of the observed dipole moments have also been discussed in terms of chain flexibility.

Permittivity and density of the systems (monoglyme, diglyme, triglyme, or tetraglyme+n-heptane) at several temperatures

“…The values thus obtained and the value of l g are in table 9. This value matches one of those indicated in [38] where l g was determined in dilution of n-hexane and benzene.…”

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

“…triglyme and tetraglyme) and crown ethers (e.g. 18-crown-6, 15-crown-5 and 12-crown-4) in H 2 O and D 2 O; their results suggest that the hydration of crown ethers increases with their size and is predominated by the hydrophobic hydration of -CH 2groups; they also indicate that there is a subtle difference between the hydration of the -CH 2 CH 2 O-group in crown and straight-chain compounds, and the compressibility data reveal a more negative compressibility due to the addition of a -CH 2 CH 2 O-group to crown 23 Heat capacity at 25 C (J mol À1 K À1 ) E T (30), kcal mol À1 E N T Monoglyme 1.62, 75 1.61, 57 1.59, 76 1.71 (in benzene) 76 7.18, 77 7.20, 72 7.55 78 38.2 0.231 191.14 79…”

Volumetric Properties of Binary Tetraethylene Glycol Dimethyl Ether + Heptane Mixtures between (278.15 and 353.15) K and up to 25 MPa

“…It is also observed that the internal pressure values of TEGDME are greater than those of heptane and, as expected, they increase with the mole fraction of TEGDME, ranging from 224 MPa for pure heptane at 343.15 K and 1 MPa to 337 MPa for pure TEGDME at 283.15 K and 20 MPa. This is due to the presence of the polar group (µ ) 2.4 D for TEGDME, 35 while µ is close to 0 for heptane 36 ). This behavior has also been found in a previous work for other mixtures.…”