Halogenoalkanes

Producing Halogenoalkanes: (3)

• Alkanes: free - radical substitution

• Alkenes: electrophilic addition of HX (or by reacting KBr with conc H2SO4 or H3PO3)

• Alcohols: reactions with: PCl3, (H3PO3); PCl5, (HCl, POCl3); SO2, (HCl, SOCl2)

Reactions of Halo (4) tell me every single damn thing about amines

• Alkenes: with NaOH (ethanolic), heat under reflux

• Alcohols: with H2O/ NaOH (aq), aka, hydrolysis, heat under reflux

• Nitriles, with KCN, HEAT under reflux

• AMINES: WITH NH3 in excess, in ethanol, heat under pressure, + H2O

Markovnikov’s rule <3

Amines: How does it work / type of reaction? the “phile” ? The chemical equation

How does it work?

• Nucleophilic substitution, side product + HX or none

Nucleophile: NH3

Product:

1. before: -amine + hydrohalogen

2. after: (when it’s in excess, Ammonia neutralises ACID)

| NH₃ + HBr → NH₄ Br

Chemical equation

• CH3CH2Br + 2NH3 → CH3CH2NH2 + NH4Br

Conditions:

• NH3 in ethanol

• Heat

• Sealed in container

Nitriles Niggrow nhớ sao?!?!, the “phile” in question, Side product, condition

• Nucleophilic substitution, in turn X- ion is left out (side product)

• Nucleophile: CN- ion

• Chemical equation:

• CH₃CH₂Br + CN- → CH3CH2CN + Br-

• Conditions: Add KCN → NIGGROEW NHỚ BÔI KCN!!!

• HEAT UNDER REFLUX

• CYANO!! or Nitrile

Producing Halo (how many things?)

, which are:

• Free radical substitution of Alkanes using Br, Cl

• Electrophilic addition of alkene using X2 or HX (conditions: at room temp)

• Substitution of Alcohol:

1. HX (or KX and H2SO4 or H3PO4)

2. PCl3 and heat: → halo + H3PO3

3. PCl5 and at room temp: → HCl + PCl3

Heat under reflux

Heating method using a condeser, prevent the vapour from reagents to escape

Alcohols (Nucleophile, conditions)

• Hydrolysis (Add H₂O) side product: HBr

• OR through the reaction with NaOH (aq) (substitution reaction) aka dilute alkali

• nucleophile: H2O or OH-

• Conditions: Heat under reflux

• Note: Hydrolysis slower

Identifying halogen: reagents, any conditions, add to what? Colour?

Slowly occurs by adding AgNO3 solution in a mixture of ethanol and water

Forms AgX precipitate

AgI - pale yellow

AgBr - cream

AgCl - white

SN₁

S & N: Substitution nucleophilic

1 or 2: order of reaction, how many factors determine the RoR

S_N2

One stage, occurs with primary

central shows TRANSITION

How it works:

1st

Nu attacks the Carbon

Transition:

AT THE SAME TIME, Nu - - - - C and - - - - leaving group

Note: PARTIAL CHARGES BEFORE AND AFTER

Nu attacks from opposite side ‘cause Like charges repel

S_N1

2 STAGES, HUHU NHỚ ATVNCG QUÁ ĐI MẤT

First:

electrons → X

Second:

Nu → C+ (Trigonal Planar intermediate)

ions left…

Involves Carbocations which is stabilised by the inductive effect

=> Tertiary

*HIGHLY IMPORTANT!!!: first step, there’s might not be no attack

Reactivity (electronegativity, bond length → ?)

Enegativity: decreases down the group

Size of Partial charges (GOING DOWN)

Bond length increases → Atomic size

Making Alkene (Does it include X or no?)

Elimination reaction, side product: NaX + H₂O

reagents: NaOH

Conditions: NaOH(_ethanol)

Heat under reflux