Alcohols

Oxidation

Heat

KMnO₄/H+ → purple to colorless

K₂Cr₂O₇/H+ → orange to green

Esterification

alcohol + carboxylic acid + h2so4

Test for Alcohols

• ethanoic acid, conc Sulfuric, warm NaHCO3

+PCl5

• anhydrous

Lucas Test

Lucas Reagent → conc. HCL and ZnCl2

1 → white cloudiness only on heating

2 → white cloudiness after 5-10 mins

3 → white cloudiness immediately

Hydrogen Halides (Hbr)

conc of hydrogen halide, reflux and heat

Dehydration - Preparation of Alkene

cH2So4, 180

Dehydration to form an ether

• c H2So4, 140*C

Iodoform

→ vicinal Ch3 to Oh

→ NaOH

Preparation of Alcohols - Hydration of Alkenes

• conc Sulfuric acid

• reflux with warm H30

Preparation of Alcohols - Reduction of Aldehydes/Ketones and Carboxylic acids

LiAlH4 in dry ether → reduces all groups

NaBH4 → NOT CARBOXYLIC ACIDS

Preparation of Alcohols - Alkaline Hydrolysis of Haloalkanes

Heat, reflux NaOH

Industrial Preparation of Ethanol - Fermentation of Sugars

• Yeast provides - zymase

• no air → prevent oxidation of ethanol

• yeast is killed at 15%

• 35 degrees allowing the enzyme to work

Industrial Preparation of Ethanol - Steam Hydration of Ethene

• 300 degrees, 60-70atm, H3Po4

• LOW TEMP AND HIGHER PRESSURES → BETTER YIELD

Characteristics of Polyhydric Alcohols

• better solubility

• more viscous

ALL BCS OF HYDROGEN BONDING!!

Physical Properties of Alcohols

• b.p and m.p increase with the mass of alchol → more id-id

• branching reduces it bcs poorer packing

• Longer chain alcohols are not soluble in water as the surface area of id-id increases but the surface are of the h-bond doesnt