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Wikipedia / Polar aprotic solvent

A polar aprotic solvent is a solvent that lacks an acidic proton and is polar. Such solvents lack hydroxyl and amine groups. In contrast to protic solvents, these solvents do not serve as proton donors in hydrogen bonding, although they can be proton acceptors. Many solvents, including chlorocarbons and hydrocarbons, are classifiable as aprotic, but polar aprotic solvents are of particular interest for their ability to dissolve salts. Methods for purification of common solvents are available.

Solvent

Chemical formula

Boiling point

Dielectric constant

Density

Dipole moment (D)

Comment

Polar aprotic solvents

acetone

(CH3)2CO

56.1 °C

21.8

0.785 g/cm3

2.91

reacts with strong acids and bases, somewhat protic due to keto-enol equilibrium and the unavoidable presence of water due to aldol condensation

acetonitrile

CH3CN

82 °C

38.3

0.776 g/cm3

3.20

reacts with strong acids and bases

dichloromethane

CH2Cl2

39.6 °C

9.08

1.327 g/cm3

1.6

low boiling point

dimethylacetamide

(CH3)2NCOCH3

165 °C

37.8

0.94 g/cm3

3.72

reacts with strong acids and bases

dimethylformamide

(CH3)2NCHO

153 °C

36.7

0.95 g/cm3

3.86

reacts with strong acids and bases

N-methylpyrrolidone

CH3NCOC3H6

203 °C

32.3

1.028 g/cm3

4.09

high boiling point

dimethylimidazolidone

(CH3N)2COC2H4

225 °C

37.6

1.056 g/cm3

4.09

high boiling point

dimethylpropyleneurea

(CH3N)2COC3H6

246.5 °C

36.1

1.064 g/cm3

4.23

high boiling point

dimethyl sulfoxide

(CH3)2SO

189 °C

46.7

1.10 g/cm3

3.96

reacts with strong bases, difficult to purify

ethyl acetate

C2H5OCOCH3

77.1°C

6.02

0.902 g/cm3

1.88

reacts with strong bases

hexamethylphosphoramide

[(CH3)2N]3PO

232.5 °C

29.6

1.03 g/cm3

5.38

high boiling point, high toxicity

propylene carbonate

CH3C2H3O2CO

242 °C

64.9

1.205 g/cm3

4.94

high boiling point

pyridine

C5H5N

115 °C

13.3

0.982 g/cm3

2.22

reacts with protic and Lewis acids

sulfolane

C4H8SO2

286 °C

43.3

1.27 g/cm3

4.8

high boiling point

tetrahydrofuran

C4H8O

66 °C

7.6

0.887 g/cm3

1.75

polymerizes in presence of strong protic and Lewis acids

References