Solvent Effects on Substitution Reactions: Dielectric Constants and Classifications

Vocabulary flashcards detailing solvent classifications (polar aprotic, nonpolar aprotic, protic), their structures, dielectric constants, and suitability for SN1 or SN2 substitution reactions.

Polar aprotic solvents

A class of solvents ideal for $S_N2$ reactions that possess dipole moments but lack acidic protons, including DMSO, acetonitrile, DMF, and acetone.

Protic solvents

A class of solvents required for $S_N1$ reactions that contain hydrogen atoms bonded to electronegative atoms, including water, formic acid, methanol, ethanol, and acetic acid.

Nonpolar aprotic solvents

Solvents with low dielectric constants that lack acidic protons, including dichloromethane, diethyl ether, toluene, and hexane.

DMSO

A polar aprotic solvent ideal for $S_N2$ reactions with the chemical structure $(CH_3)_2S=O$ and a dielectric constant of $48.9$.

Acetonitrile

A polar aprotic solvent ideal for $S_N2$ reactions with the chemical structure CH_3C\tbond N and a dielectric constant of $37.5$.

DMF

A polar aprotic solvent ideal for $S_N2$ reactions with the chemical structure $(CH_3)_2NCHO$ and a dielectric constant of $36.7$.

Acetone

A polar aprotic solvent ideal for $S_N2$ reactions with the chemical structure $(CH_3)_2C=O$ and a dielectric constant of $20.7$.

Dichloromethane

A nonpolar aprotic solvent with the chemical structure $CH_2Cl_2$ and a dielectric constant of $9.1$.

Diethyl ether

A nonpolar aprotic solvent with the chemical structure $(CH_3CH_2)_2O$ and a dielectric constant of $4.3$.

Toluene

A nonpolar aprotic solvent with the chemical structure $C_6H_5CH_3$ and a dielectric constant of $2.3$.

Hexane

A nonpolar aprotic solvent with the chemical structure $CH_3(CH_2)_4CH_3$ and a dielectric constant of $1.9$.

Water

A protic solvent required for $S_N1$ reactions with the chemical structure $H_2O$ and a dielectric constant of $79$.

Formic acid

A protic solvent required for $S_N1$ reactions with the chemical structure $HCO_2H$ and a dielectric constant of $59$.

Methanol

A protic solvent required for $S_N1$ reactions with the chemical structure $CH_3OH$ and a dielectric constant of $33$.

Ethanol

A protic solvent required for $S_N1$ reactions with the chemical structure $CH_3CH_2OH$ and a dielectric constant of $24$.

Acetic acid

A protic solvent required for $S_N1$ reactions with the chemical structure $CH_3CO_2H$ and a dielectric constant of $6.2$.