Ochem SN1, E1, SN2, E2 reaction differences

ROH, H₂O, X^-

S_N1 and E1 Attacking Species

CN^-, RS^-, RCO₂^-, X^-

S_N2 Attacking Species

R₃C^-, R₂N^-, RO^-, H^-, LDA, ^tBuO^-

E2 Attacking Species

Methyl

Only S_N2 can react with this degree of substitution

1°

S_N2 and E2 can react with this degree of substitution

2°

All can react with this degree of substitution

3°

S_N1, E1, and E2 can react with this degree of substitution

H₂O, Ethanol, Ethanoic Acid

Polar Protic Solvent, increases rate of S_N1 and E1, follows charge stability but reverses size trend

DMSO, acetone, DMF

Polar Aprotic Solvent, increases rate of S_N2 and E2 (unless E2 base is OH^-), follows charge stability

High heat reaction

Favors elimination

Low heat reaction

Favors substitution