Edexcel Chemistry Organic reactions & mechanisms

Alkane to Haloalkane

Halogen X2 and UV

Haloalkane to Alcohol

warm aq NaOH reflux, sub OR Mg dry ether then carbonyl then dilute acid

Alkene to Alkane

H2, Ni catalyst 150 degs

Alcohol to Haloalkane

KBr 50% c H2SO4 20 degs / PCl5 or HCl 20 deg

Alkene to Alcohol

H2O (steam)/H3PO4 300 degrees 60-70 atm

Alcohol to Alkene

c H3PO4, heat, 170 degs

secondary alcohol to ketone

K2Cr2O7, H2SO4, reflux

Primary alcohol to aldehyde

K2Cr2O7/ d H2SO4, distil

primary alcohol to carboxylic acid

K2Cr2O7, H2SO4, reflux

Haloalkane to Nitrile

KCN, ethanol, reflux

Haloalkane to Amine

NH3/ethanol

EXCESS ETHANOLIC AMMONIA

ketone to secondary alcohol

LiALH4

de

aldehyde to primary alcohol

LiAlH4 de

Alcohol to Ester

Carboxylic acid/conc. H2SO4, heat

OR

Acid anhydride

OR acyl chloride (nuc ad/elim)

Carboxylic acid to ester

Alcohol/conc H2SO4/heat

Aldehyde/Ketone to Hydroxynitrile

KCN(aq)/H+(aq) or HCN ethanol

Hydroxynitrile to Amine

H2/Ni high temp and pressure catalalytic hydrogenation

Hydroxynitrile/Nitrile to Carboxylic acid

H2O, HCl, Heat

ester to carboxylic acid

dilute acid, heat

Ester to Carboxylate

OH-, heat

Acyl chloride to ester

alcohol 20

Acyl chloride to carboxylic acid

cold H2O

Carboxylic acid to acyl chloride

PCl5

rtp

Acyl chloride to primary amide

NH3 rtp

Acyl chloride to secondary amide (N sub)

primary amine rtp

nucleophilic addition

Carbonyl compounds with NaBH4

Ketones/aldehydes to hydroxynitriles

Nucleophilic substitution

Haloalkane to alcohol

Electrophilic addition

Alkene to haloalkane

Electrophilic substitution

Benzene

Kekule's model

Evidence to disprove Kekule's model

Does not react readily with bromine (does not undergo electrophilic addition)

Hydrogenation enthalpy less exothermic than expected

Length of C-C bonds

Delocalised model of benzene

Each carbon uses 3 out of 4 electrons to bond to 2 other carbons

Each electron has electron in p-orbital

P-orbitals overlap sideways above and below the plane to form ring of electron density

Creates system of pi-bonds

Phenol to Nitrophenol

dilute HNO3

Friedel-Crafts Acylation

RCOCl, AlCl3

What can phenol not react with?

Na2CO3

Why is phenol more reactive than benzene?

Lone pair of electrons in p-orbital of oxygen atom delocalise into the benzene ring

Electron density increased

Less stable

More susceptible to electrophilic attack

Bromination of phenol

Forms white ppt

Bromine decolourises

Room temp.

Nitration of phenol

Room temperature and dilute nitric acid are the only reactants and conditions required (with the nitration of benzene, higher temperatures (55^oC) and concentrated sulfuric acid are also necessary).

Test for carbonyl group

Add 2,4-DNPH

If present, orange ppt forms

Recrystallise

Measure melting point

Compare to known values

Test for aldehydes

Tollens reagent: silver mirror if aldehyde present

Silver ions act as oxidising agent

Aldehyde oxidised to carboxylic acid

Why are carboxylic acids soluble in water?

Polar C=O and O-H bonds allowing them to hydrogen bond.

Carboxylic acids and metals

Hydrogen gas formed (effervescence)

Metal disappears

Carboxylic acid and metal oxide

salt, water

Carboxylic acid and alkali

salt, water

Carboxylic acid and carbonate

Salt, water and carbon dioxide

Why should preparation of acyl chloride be carried out in a fume cupboard?

Toxic gases produced (HCl, SO2)

Acyl chloride and water

Violent reaction

HCl and carboxylic acid formed

Ammonia + acyl chloride

Primary amine + NH4Cl

Primary amine + acyl chloride

Secondary amide + CH3NH3+Cl-

Hydrolysis of Nitriles

nitrile + hcl + 2h20 ---> carboxylic acid + nh4cl

Distillation

A process that separates the substances in a solution based on their boiling points

Reflux

What do anti-bumping granules do?

Prevent large bubbles - even heating

How to purify an organic liquid

Use separating funnel

Add NaHCO3 - this will produce CO2

Invert funnel and open tap to release CO2 - invert until no more gas released

Add more water, the aqueous layer will grow

Separate the layers

Add a drying agent until it stops clumping and a clear solution is formed

Redistil to remove organic impurities

Large range = impure

How to purify an organic solid

Dissolve solid in minimum amount of hot solvent

Filter hot under reduced pressure to remove insoluble impurities (anti-bumping granules)

Leave to cool

Crystals reform

Wash crystals to remove soluble impurities

Dry crystals

Check purity using melting point or TLC

What does a yield over 100% mean?

Not dried properly

What is TMS used for?

Standard reference chemical against which shifts are measured

Gives shift of 0

Stereoisomers

molecules that have the same structural formulas and bonding patterns but different arrangements of atoms in space

Structural isomers

Molecules with the same molecular formula but with different structural arrangements of atoms.

What is a sigma bond?

Orbitals completely overlap

What is a pi bond?

Partials sideways overlap of adjacent p orbitals above and below the plane of the bonding carbon atoms.

Cis/trans isomerism

A special type of E/Z isomerism in which there is a non-hydrogen group and a hydrogen atom on each C of a C=C double bond: the cis isomer (Z isomer) has the H atoms on each carbon on the same side; the trans isomer (E isomer) has the H atoms on each carbon on different sides of the bond.

What is the most stable carbocation?

tertiary carbocation

Recycling polymers

Conserve finite fossil fuels

Decrease waste going to landfill

Polymers must be sorted by type

PVC recycling

Disposal and recycling of PVC hazardous due to high chlorine content

Dumping PVC in landfill not sustainable

Grind PVC and use to manufacture new products

waste polymers as fuel

Some have high stored energy value

Can be incinerated to produce steam to power turbine producing electricity

Feedstock recycling

Chemical and thermal processes that can reclaim monomers, gases or oil from waste polymers

Bioplastics

produced from plant starch, cellulose, plant oils and proteins

Biodegradable polymers

polymers that can be broken down by microorganisms into water, carbon dioxide and biological compounds

Photodegradable polymers

Contain bonds that are weakened by absorbing light to start the degradation

Nitrogen oxide radicals and ozone depletion

b3nzene halobensene

X2 hallogen carrier, 20 degrees

benzene nitrobenzene

c HNO3 c H2SO4 below 55 degrees

nitrobenzene phenylamine

tin conc HCl, reflux then NaOH

benzene aklyl benzene

halogenoalkane, ALCl3 catalyst, reflux

benzene phenylketone

acyl chloride, AlCl3 catalyst , reflux

phenol to 2,4,6 tribromoophenol

br water, 20 degres