Chemistry: Alcohols and esters

Acidity (what determines it?) + Compare the acidity of ethanol and water

• The ability to donate proton

More Polar -OH bond is, stronger acid

Weaker acid:

• Positive inductive effect, -OH in ethanol is less polarised

• -OH(-) => conjugate base of water

• C2H3O- : conjugate base of ethanol; O is more negative (+ Inductive effect) → more likely to re-bond with H+ → less stable, weaker

Summary: Ways to Produce? Reagents?

Produce (5 ways)

• Alkenes: (2): hydration (Heat + H3PO4) NUOC (STEAM) A36, nuoc lanh oxidation with cold dilute ACIDIFIED KMnO4 → COLD DILUT → MILD O AGENT, = ISN’T FULLY BROKEN

• Halogenoalkane, hydrolysis with H2O (aq) + nucleophilic substitution + Heat

• Aldehydes + Ketones: reduction with LiAlH4, NaBH4; reduced to your origin & 2[H] * No condition

• Carboxylic acid: reduction with LiAlH4, 4[H] * No condition

• Ester: hydrolysis with dilute acid / alkali

• Reactions (4)

• Oxygen (Combustion): sufficient oxygen

• Substitution with HX or KBr conc H₂SO₄ / H₃PO₄ (Basically 4 for Halogenoalkanes)

• Na_(s)

• Dehydration reaction to alkene

• Oxidation to Aldehydes / Ketones w/ Acidified K₂Cr₂O₇

Condensation reaction

Two molecules are combined to form a larger molecules and at the same time eliminating a smaller molecule

Hydrolysis of Esters (easy) (Condensation reaction) → Producing

Add dilute Acid / Alkali + heat → condensation occured, alcohol forms!

easy: no need for concentrated

General form:

Add acid → like original: an alcohol + carboxylic acid : Acid ←> Alcohol

Add alkali → almost: alcohol (obvi) + … -oate (Eg: Sodium ethanoate)

what pass is passed

Combustion → reactions

→ CO₂ + H₂O

Na

General equation:

Alcohol + sodium → Sodium Alkoxide + H₂ → Identifying reagents so don’t you dare to forget!!!

Aldehydes + Ketones

Acidified K₂Cr₂O₇ (Mild OXIDATION THO!) / KMnO₄

Primary alcohol: heat & oxidising agent → Aldehyde (distilled off) +H₂O → Carboxylic acid (reflux)

Secondary alcohol: Ketone

Identify alcohols
Cr₂O₇^2- colour is green

basically change from orange → green if it’s either primary or secondary

Dehydration to alkene

Al₂O₃ + heat or A CONCENTRATED ACID

Esterification (YES)

Carboxylic acid + conc H₂SO₄ Catalyst

Deduce this + to react with wut? to form wut??

CH3CH(OH)

with aqueous alkaline I₂

to form pale yellow precipitate CHI₃ (Tri - iodomethane) + RCO₂^-

Substitution → Cl

PCl3 + heat, PCl₅ → HCl (steamy white fumes) proves presence of alcohol, HCl → H₂O, SOCl₂

Bromine

• HBr or reaction of NaBr + conc H₂SO₄ → HBr + NaBH₄ (nas is for halogenoalkane….KBr + conc H₂SO₄)

• or

• 2P + 3Br₂ → 2PBr₃

→ Halogenoalkane + P(OH)₃

Iodine (normally)

• 2P + 3I₂ → 2PI₃

→ Halogenoalkane + P(OH)₃