Chapter 16 Flashcards
What are the 3 steps to purify an organic product?
- Separating funnel
- Drying agent
- Distilllation
What is a separating funnel used for?
- It is used to separate the organic and aqueous layers in organic synthesis
How do separating funnels work?
- Make sure the tap is closed
- Pour the mixture into the separating funnel, put on the stopper and invert it to mix the layers, and then leave them to settle
- In order to tell the layers apart, you add water- the aqueous layer will increase in size
- Place a conical flask underneath the separating funnel, and use it to collect the lower (more dense) layer, and repeat for the other layer
What other part of the purification process happens inside the separating funnel?
- Removing acid impurities that may exist due to your preparation method
How do you remove acid impurities?
- Add aqueous sodium carbonate and shake in the separating funnel
- Hold the funnel upside down
- Any acid will react with sodium carbonate and release carbon dioxide
- Slowly open the tap to release the gas
Out of the two products, which is the desired product, and what has to be done as a result?
- The organic product
- Water has to be removed
How is water removed from the organic product?
- You add a drying agent, which is an anhydrous salt (it therefore takes up the water to become hydrated)
Give 3 examples of drying agents.
- Anhydrous calcium sulfate
- Anhydrous magnesium sulfate
- Anhydrous calcium chloride
Why do you distill the organic product?
- Some organic products have similar boiling points, so this removes any impurities
What can alkanes react to form?
- Haloalkanes
Alkane to haloalkane. Reactants, conditions and mechanism if applicable. Give 1 extra detail.
- Reactants: alkane and halogen
- Conditions: UV
- Mechanism: radical substitution
- Initiation:
Br-Br -UV-> ·Br + ·Br
(- Homolytic fission) - Propagation:
·Br + CH4 -> ·CH3 + HBr
·CH3 + Br2 -> CH3Br + ·Br
Termination:
·Br + ·Br -> Br2
·CH3 + ·CH3 -> C2H6
·CH3 + ·Br -> CH3Br
What can alkenes react to form?
- Alkanes
- Alcohols
- Haloalkanes
- Dihaloalkanes
Alkene to alcohol. Reactants, conditions and mechanism if applicable. Give 1 extra detail.
- Reactants: alkene and steam
- Conditions: H3PO4 (or concentrated sulfuric acid) catalyst, > 100°C (already indicated if you said steam/ wrote the gas state symbol)
- Positional isomerism is possible
Alkene to alkane. Reactants, conditions and mechanism if applicable.
- Reactants: alkene and hydrogen
- Conditions: nickel catalyst
Alkene to haloalkane. Reactants, conditions and mechanism if applicable. Give 3 extra details.
- Reactants: alkene and hydrogen halide (can be concentrated hydrochloric/ hydrobromic acid)
- Conditions: room temperature, no catalyst
- Mechanism: electrophilic addition
- Positional isomerism is possible, Markownikoff’s rule
