Dipole moment diethyl ether

Ethers like water and alcohols are polar molecules Diethyl ether for example has a dipole moment of 1 2 D Cyclic ethers have larger dipole moments ethylene oxide and tetrahydrofuran have dipole moments m the 1 7 to 1 8 D range—about the same as that of water (1 8D)... 

The rate enhancement of the Diels-Alder reaction in LP-NM has been attributed to the high dipole moment of nitromethane (3.40 D) in comparison with diethyl ether (1.33 D). 

Although ethers lack the polar hydroxyl group of alcohols, they are still strongly polar compounds. The dipole moment of an ether is the vector sum of two polar C—O bonds, with a substantial contribution from the two lone pairs of electrons. Table 14-1 compares the dipole moments of dimethyl ether, diethyl ether, and tetrahydrofuran (THF) with those of alkanes and alcohols of similar molecular weights. An ether such as THF provides a strongly polar solvent without the reactivity of a hydroxyl group. 

An example of reaction type (c) in Table 5-4 is the well-known Menschutkin reaction [30] between tertiary amines and primary haloalkanes yielding quaternary ammonium salts. Its solvent dependence was studied very thoroughly by a number of investigators [51-65, 491-496, 786-789]. For instance, the reaction of tri-n-propylamine with iodomethane at 20 °C is 120 times faster in diethyl ether, 13000 times faster in chloroform, and 110000 times faster in nitromethane than in -hexane [60]. It has been estimated that the activated complex of this Menschutkin reaction should have a dipole moment of ca. 29 10 Cm (8.7 D) [23, 64], which is much larger than the dipole moments of the reactant molecules (tris- -propylamine 2.3 10 Cm = 0.70 D iodomethane 5.5 10-3 1 64 D) [64]. 

Of these, probably the most decisive are type 2 and the combination of types 1 and 3. It is difficult to rationalize the weak H bonds formed by acetonitrile as a base (molecular dipole moment of 3.44 d) and the strong H bonds formed by trimethylamine (molecular dipole moment of 0.7 d) together with the interpretation that an acid A—H forms H bonds with these bases because of the electrostatic interaction of the A—H dipole with point charges on the nitrogen atoms. Another interesting comparison is afforded by the approximately equal H bond properties of acetone, diethyl ether, and dioxane, with dipole moments of 2.85 D, 1.15 D, and 0.4 d, respectively. These qualitative discrepancies can be backed by a substantial body of quantitative data. Table 8-1 collects some of these data, and verifies the absence of any systematic dependence of enthalpy of H bond formation upon the molecular dipole moment. Compilations of At, (814) and of AFshow that these properties are similarly unrelated to /i- Certainly these data show that the strength and behavior of a H bond are not determined in a direct way by the dipole moment. This lack of dependence is not easily reconciled with... 

Ethanediol. See Ethylene glycol Ethanoic acid. See Acetic acid Ethanol, 128, 130, 580-581 acidity of, 135, 740-741 and benzaldehyde, acetal from, 669 biological oxidation of, 600—602 chemical shifts, 606 conversion to diethyl ether, 592 dehydration of, 182 dipole moment of, 130, 863 by fermentation, 580-581 hydrogen bonding in, 130-131 industrial preparation of, 223, 581 physical properties of, 130, 132-133, 580 reduction of aryl diazonium salts by, 894, 907... 

Table 16.1 compares the physical properties of diethyl ether to those of an alkane (pentane) and an alcohol (1-butanol) of similar size and shape. With respect to boiling point, diethyl ether resembles pentane more than 1-butanol. With respect to dipole moment and solubility in water, the reverse is true. 

Accordingly, a linear relationship between dv and (D —l)/(D + 2) in different constitutions of the mixture is expected. The slope of the line is equal to the value of C and from C one obtains the dipole moment in the excited state, For this purpose, diethyl ether and acetonitrile were selected. Their refractive indexes are almost identical, 1.356 and 1.344, respectively however, the dielectric constants are 4.3 for diethyl ether and 37.5 for acetonitrile - a wide difference. 

Diethyl ether has a small dipole moment and can be considered Intermediate between polar and nonpolar. ... 

Ethers such as diethyl ether dissolve a wide range of polar and nonpolar organic compounds. Nonpolar compounds are generally more soluble in diethyl ether than alcohols because ethers do not have a hydrogen bonding network that must be broken up to dissolve the solute. Because diethyl ether has a moderate dipole moment, polar substances dissolve readily in it. 

---