Key Concepts In Organic Chemistry: Alcohols, Ethers & Thiols
-Alcohols have the general formula R-OH. The O atom is always ignored in calculations of units of
unsaturation. The O in alcohols is sp hybridized (two sp orbitals are occupied by non-bonding pairs).
Thiols have the general formula R-SH. The S atom is always ignored in calculations of units of
unsaturation. In alcohol/thiol naming, the OH/SH group always takes priority over π bonds. Alcohols are
classed as 1°, 2° or 3° depending on the type of sp C atom to which the OH group is bonded.
-Hydrogen bond refers to the attractive force between an H of one functional group and the δ- of the
lone pair on the O (or other) atom of another. A hydrogen bond is not a true (σ) bond, but is instead a
coulombic attraction between partial charges on atoms in neighbouring molecules.
-Alcohols tend to have very high boiling points for their size. OH groups greatly increase the solubility of
organic molecules in water. One of the most noteworthy physical feature of thiols is their incredibly
-Like H 2, alochols and thiols are amphiprotic, they can function as acids (in the presence of sufficiently
strong bases) or as bases (in the presence of sufficiently strong acids). Alcohols, like water, also react
with Group 1 and 2 metals to form alkoxide salts, with the liberation of hydrogen:
ROH + Na RONa + 1/2H 2
-The conversion of alcohols to alkyl halides is a substitution reaction that proceeds by an SN or an SN
mechanism, depending on the structure of the alcohol. In the reaction of alcohol with HX (X = Cl, Br, I),
tertiary alcohols react by an SN me1hanism, but only after the hydroxyl group is protonated to make an
oxonium ion. This converts the OH to an excellent LG, OH . Prim2ry and secondary alc