Organic Chemistry: Reactions and Synthesis Flashcards
How do we convert an alkene into an alkane? How much hydrogen do we need?
Add hydrogen. You need one hydrogen molecule for each double bond present.
What is the reaction from an alkene to an alkane called?
Hydrogenation.
What are the conditions for the reaction from an alkene to an alkane?
A temperature of 150°C and a Nickel catalyst.
How do we convert a haloalkane into an alkane?
Add a hydrogen halide so the halogen is replaced by a hydrogen.
How do we convert an alkane into an alkene? How much hydrogen do we get?
Remove hydrogen and you’ll get one molecule of hydrogen for each double bond created.
What is the reaction from an alkane to an alkene called?
Dehydrogenation.
What is the reaction from an alkane to a haloalkane called?
Free radical substitution.
How do we convert an alkane into a haloalkane?
Substitute one hydrogen for one halogen.
What are the conditions for the reaction from an alkane into a haloalkane.
UV light.
What are the three steps for Free Radical Substitution?
Initiation, Propagation and Termination
What happens in initiation in Free Radical Substitution? What is this process called?
UV light splits up two halogens into radicals. This is called homolytic fission.
What happens in termination in Free Radical Substitution?
Any two free radicals combine to make a stable molecule.
How do we convert an alcohol into an alkene?
Eliminate water from the alcohol.
What is the reaction from an alcohol to an alkene called?
Dehydration.
What are the conditions for the reaction from an alcohol to an alkene?
Catalyst of concentrated H₂SO₄
How do we convert a haloalkane into an alkene?
Remove the halogens from the haloalkane to make an alkene.
What is the reaction from a haloalkane to an alkene called?
Dehalogenation.
How do we convert an alkene into an alcohol?
Add water to the alkene.
What is the reaction from an alkene to an alcohol called?
Hydration.
What are the conditions for the reaction from an alkene to an alcohol?
Steam at 300°C with concentrated phosphoric acid
How do you convert an alkene into a haloalkane?
Add a halogen to an alkene.
What is the reaction from an alkene to a haloalkane called?
Electrophilic Addition
What happens in electrophilic addition?
- Electron pairs in the carbon double bond repel bromine, inducing dipole.
- π bond is attracted to the positive bromine dipole so the bromine dipoles come closer further repelling the σ bond.
- With the σ bond gone, the remaining electrons bond to one bromine creating a carbocation, where the other bromine will bond to.
What are the conditions for electrophilic addition?
H₂SO₄
How do we convert an alcohol to a haloalkane?
Replace the hydroxide ion with a halide ion.
What are the conditions for the reaction from an alcohol to a haloalkane?
Concentrated H₂SO₄ and a spectator ion.
How do we convert a haloalkane to an alcohol?
Replace the halide ion with a hydroxide ion
What is the reaction from a haloalkane to an alcohol called?
Nucleophilic Substitution
What happens in nucleophilic substitution ?
- The bromine will be more electronegative than the carbon so there are dipoles.
- Electrons in the C-Br bond are repelled by the electrons from the new -OH bond.
- Heterolytic fission takes place as the bromine atom gets both electrons from the carbon.
What are the conditions for the reaction from a haloalkane into an alcohol
Ethanol and NaOH
What do Alcohols produce when combusted?
Carbon Dioxide and Water
What types of Alcohols can we oxidise?
Primary and Secondary.
What mixture do we use to oxidise alcohols.
K₂Cr₂O₇ + H₂SO₄
When an alcohol is oxidised, what is the colour change and why?
The colour will change from orange to green because the orange contains dichromate ions whilst the green contains chromium ions.
What happens if we oxidate a primary alcohol using distillation?
The alcohol turns into water and an aldehyde.
What happens if we oxidate a primary alcohol using reflux?
The alcohol will turn into a carboxylic acid and water.
What is reflux?
Reflux is the continuous evaporating and condensing of a reaction mixture.
What happens if we oxidate a secondary alcohol?
The alcohol will turn into a ketone.
What happens if we oxidate a tertiary alcohol?
Nothing will happen as tertiary alcohols can’t be oxidised.
