Alcohols, Phenols and Ethers - Preparation and Properties of Alcohols and Phenols

Preparation of Alcohols from Alkenes: Acid catalyzed hydration follows Markovnikov's rule, whereas Hydroboration-Oxidation ($B_2H_6$ followed by $H_2O_2/OH^-$) results in Anti-Markovnikov addition of $H_2O$.

Preparation of Alcohols from Carbonyl Compounds: Aldehydes are reduced to $1^\circ$ alcohols and ketones to $2^\circ$ alcohols using $LiAlH_4$, $NaBH_4$, or $H_2/Pd$.

Grignard Reagent Synthesis: Formaldehyde yields $1^\circ$ alcohols, other aldehydes yield $2^\circ$ alcohols, and ketones yield $3^\circ$ alcohols when reacted with $RMgX$.

Industrial Preparation of Phenol: Phenol is manufactured from Cumene (isopropylbenzene). Air oxidation of cumene produces cumene hydroperoxide, which is decomposed by dilute acid to yield Phenol and $CH_3COCH_3$ (Acetone) as a valuable byproduct.

Acidity of Alcohols and Phenols: Phenols are more acidic than alcohols due to the resonance stabilization of the phenoxide ion ($C_6H_5O^-$). Electron-withdrawing groups ($-NO_2$) increase acidity, while electron-donating groups ($-CH_3$, $-OCH_3$) decrease it.

Lucas Test: Used to distinguish between $1^\circ$, $2^\circ$, and $3^\circ$ alcohols using Lucas reagent (conc. $HCl + ZnCl_2$). $3^\circ$ alcohols show immediate turbidity, $2^\circ$ after 5 minutes, and $1^\circ$ only upon heating.

Reimer-Tiemann Reaction: Treatment of phenol with $CHCl_3$ and aqueous $NaOH$ followed by acidification introduces an $-CHO$ group at the ortho position, forming Salicylaldehyde.

Kolbe's Reaction: Phenoxide ion reacts with $CO_2$ followed by acidification to produce $2$-hydroxybenzoic acid (Salicylic acid).