Dimethyl ether dipole moment

View molecular models of dimethyl ether and ethylene oxide on Learning By Modeling Which one has the greater dipole moment Do the calculated dipole moments bear any relation ship to the observed boiling points (ethylene oxide +10°C dimethyl ether —25°C) d... 

Drawings using arrows help us see why acetone has a larger dipole moment than dimethyl ether. The arrows show the charge displacement for each polar bond. Experimental values for the dipole moments are butane, 0 D methyl ethyl ether, 1.12 D and acetone, 2.88 D. 

Molar Kerr constants mK and dipole moments squared of polytoxyethylene giycoils (POEG) and polyjoxyethylene dimethyl ether)s (POEDE) are reported in the isotropically polarizable solvents carbon tetrachloride, cyclohexane, and dioxane. Data for mK/x for POEG appear to reach an asymptotical value, Calculations of mK/x and /x based on the RIS model show good agreement with the experimental results. 

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. 

Deliquescent, orthorhombic, elongated, six-sided tablets from dimethyl phthalate. dj 1.282. mp 45-46. bp0J 83. Fomin of dicyandiamide begins at 122. Dipole moment in benzene at 2Cryoscopic constant (water) 26.8-28.4. Sp ht 0.547 cal/g/ C between 0° and 39. Heat of formation 14.05 kcal/mole (25 ) heat of combustion —176-4 kcal/-mole (25 ) heat of fusion 2.1 kcal/mole. Heat of vaporization 16.4 kcal/mole. Soly (g/100 g soln) in water at 15 77.5, at 43 100 in butanol at 20 28.8, in methyl ethyl ketone 50.5, in ethyl acetate 42.4. Sol in alcohols, phenols, amines, ethers, ketones. Very sparingly sol in benzene, haJogeaated hydrocarbons. Practically insol in cyclohexane. Solid cyanamide should be stored in a cool, dry place. Polymerizes at 122. Optimum pH for storage of solns is 4, Attacks various metals. Solns can be stored in grass provided they are stabilized with phosphoric, acetic, sulfuric, or boric acid. LDM in rats 125 mg /kg orally. 

Figure 23. Component dipole moments of p-chloroanisole and of hydro-quinone-dimethyl ether.

Consider each of the following molecules in turn (a) dimethyl ether, (CH3)20 (b) trimethylamine, (CH3)3N (c) trimethylboron, (CH3)3B and (d) dimethylberyUium, (CH3)2Be. Describe the hybridization state of the central atom (i.e., O, N, B, or Be) of each molecule, tell what bond angles you would expect at the central atom, and state whether the molecule would have a dipole moment. 

Rationalize the differences between the following dipole moments for water, dimethyl ether, and ethylene oxide (oxirane) ... 

In fact, the boiling point of dimethyl ether is almost as low as the boiling point of propane. Both dimethyl ether and propane lack the ability to form hydrogen bonds. The slightly higher boiling point of dimethyl ether can be explained by considering the net dipole moment. 

As with sufur dioxide, methyl chloride, and hydrogen sulfide, so with dimethyl ether there is no systematic correlation between Xmc20 (or Me2o) on the one hand, and dipole moment or dielectric constant of S, on the other. 

Consider the physical properties of the two isomeric compounds, ethanol and dimethyl etiher, presented in Table 7.3. Since the dipole moment values are so close, how can we explain the much higher normal boiling point temperature of ethanol Or, the more than double amount of energy needed to vaporize one mole of ethanol as compared to one of dimethyl ether In other words, what kind of intermolecular forces are responsible for these differences ... 

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