Reactants and conditions of organic mechanisms Flashcards
Combustion
Oxygen
Excess for complete
Limited for incomplete
Alkane -> Haloalkane
Free Rad Substitution
UV light and X2
How does UV light split a halogen molecule?
Homolytically
Haloalkane -> alcohol
Nucleophilic Substitution
Heat under reflux with aqueous NaOH
Why must substitution reactions to form alcohols be carried out in aqueous conditions?
Otherwise elimination may occur
Haloalkane -> Nitrile
Nucleophilic Substitution
Heat under reflux with ethanol KCN or NaCN
Why must KCN be ethanolic when it is used to form a nitrile and NH3 be ethanolic when forming an amine?
Otherwise an alcohol may form if there is any water present.
Haloalkane -> amine
Nucleophilic Substitution
Heat in a sealed container with ethanolic ammonia.
Haloalkane -> Alkene
Heat under reflux with ethanoic NaOH
How do the conditions effect the product when haloalkanes react with OH- ions?
Halogenoalkanes can react with hydroxide (OH-) ions in both substitution and elimation reactions.
If substitution occurs an alcohol is formed, whereas if elimination occurs an alkene is
formed.
The solvent used can help ensure more of one product is formed than the other, although final prod-
uct mixture can still contain both the alcohol and alkene.
If a hot aqueous solvent is used, more alcohol forms.
If a hot ethanolic solvent is used, more alkene forms.
Alkene -> Alcohol (addition method)
Electrophilic Addition
Conc sulphuric acid and then heat.
Alkene -> Haloalkane
Electrophilic Addition
HX
Alkene -> alcohol (hydration method)
Electrophilic Addition and Hydration
Heat with steam and an acid catalyst
Glucose -> ethanol
Fermentation
Yeast, Anaerobic Atmosphere (no oxygen) and Warm Temperature
Alcohol -> aldehyde or ketone
Oxidation
Heat and distill with acidified potassium dichromate.
Aldehyde -> Carboxylic acid
Oxidation
Heat with acidified potassium dichromate.
Reflux if straight from primary alcohol
Alcohol -> alkene
Elimination
Heat with conc acid catalyst.
Aldehyde/Keytone -> alcohol
Reduction
NaBH4
Aldehyde/Keytone -> hydroxynitrile
Nucleophilic Addition
KCN in dilute acid
Why must KCN be used instead of HCN in reactions?
HCN is very reactive and dangerous.
Why might hydroxynitriles be produced with optical isomerism?
If a chiral carbon centre is formed in the product, the final product mixture will be racemic,
containing both enantiomers in a 50:50 ratio. This is because carbonyl groups are planar and
there is equal chance of the :CN- nucleophile attacking the carbonyl group from above or be-
low the plane - producing two possible enantiomers in equal amounts
Carboxylic Acid -> alcohol
Esterification
Heat under reflux with water and conc H2SO4
Ester -> carboxylic acid and alcohol
Acid hydrolysis
Warm with aqueous dilute acid
Ester -> carboxylate ion and alcohol
Base hydrolysis
Warm with aqueous dilute base
How is acid hydrolysis used to make fuel?
Biodisel can be made by the reaction of oil (tri-ester) with methanol in the presence of an acid catalyst,
forming methyl esters that can be used as a diesel fuel.
Acyl chloride -> carboxylic acid
Nuclephilic addition elimination
Add water
Acyl chloride -> ester
Nuclephilic addition elimination
Add alcohol
Acyl chloride -> amide
Nuclephilic addition elimination
Add ammonia
Benzene -> Nitrobenzene
Electrophilic Substitution
Concentrated HNO3 and concentrated H2SO4
Formation of nitronium ion
HNO3 + 2H2SO4 -> NO2+ + H3O+ + 2HSO4-
Benzene -> aromatic ketone
Electrophilic Substitution
Warm with AlCl3 catalyst
Nitrile -> amine
Reduction
LiAlH4 in dry ether and then dilute acid, or, H2 gas and nickel catalyst.
Nitrobenzene -> Phenylamine
Reduction
HCl and Tin catalyst and then NaOH
