Section 3 : Organic Chemistry
Organic Synthesis
The synthesis of an organic compound can involve several steps. Chemists use synthetic routes to
show the reagents, conditions + any special procedures needed to get from one compound to another.
Designing Synthetic Routes
When designing synthetic routes, chemists aim to…
1. Design processes that do not require a solvent.
- Avoiding using solvents reduces both the hazards associated w/ the process + the amount of waste
created by a synthetic route.
• Solvents are often ammable + toxic so can pose safety risks.
• Having to separate solvents from products or dispose of solvents after the reaction is complete
can create a lot of waste too.
2. Design processes that use non-hazardous starting materials.
- These may be toxic, corrosive or ammable.
• Often the use of KCN is avoided as it is toxic, + other synthetic routes will be used instead
- This limits the potential for accidents + environmental damage.
3. Design production methods w/ fewer steps that have a high % atom economy.
- Chemists will always try to limit the no. of steps in a conversion as there is a loss at each step as
the % yield is not 100% for each reaction.
- A higher % atom economy means more of the starting materials are converted into useful
products, which minimises waste.
Devising a Step-Wise Synthesis for an Organic Compound
In your exam you could be asked to devise a step-wise synthesis, w/ up to 4 steps, for an organic
compound. When answering the question, make sure to include:
• Special procedures (e.g. re uxing).
• Conditions (e.g. high temp./pressure or catalyst).
• Safety precautions (e.g. fume cupboard for toxic gases such as HCl or HCN; avoid splashes on bare
skin for bromine water, acids or alkalis).
Please note the next 2 diagrams…
• Synthetic Routes for Making Organic Compounds
and
• Synthetic Routes for Aromatic Compounds
have been taken from the
A-Level Chemistry for AQA: Year 2 Student Book,
so the page no.s found in the diagrams refer to pages
found in that textbook.
fl fl fl
Organic Synthesis
The synthesis of an organic compound can involve several steps. Chemists use synthetic routes to
show the reagents, conditions + any special procedures needed to get from one compound to another.
Designing Synthetic Routes
When designing synthetic routes, chemists aim to…
1. Design processes that do not require a solvent.
- Avoiding using solvents reduces both the hazards associated w/ the process + the amount of waste
created by a synthetic route.
• Solvents are often ammable + toxic so can pose safety risks.
• Having to separate solvents from products or dispose of solvents after the reaction is complete
can create a lot of waste too.
2. Design processes that use non-hazardous starting materials.
- These may be toxic, corrosive or ammable.
• Often the use of KCN is avoided as it is toxic, + other synthetic routes will be used instead
- This limits the potential for accidents + environmental damage.
3. Design production methods w/ fewer steps that have a high % atom economy.
- Chemists will always try to limit the no. of steps in a conversion as there is a loss at each step as
the % yield is not 100% for each reaction.
- A higher % atom economy means more of the starting materials are converted into useful
products, which minimises waste.
Devising a Step-Wise Synthesis for an Organic Compound
In your exam you could be asked to devise a step-wise synthesis, w/ up to 4 steps, for an organic
compound. When answering the question, make sure to include:
• Special procedures (e.g. re uxing).
• Conditions (e.g. high temp./pressure or catalyst).
• Safety precautions (e.g. fume cupboard for toxic gases such as HCl or HCN; avoid splashes on bare
skin for bromine water, acids or alkalis).
Please note the next 2 diagrams…
• Synthetic Routes for Making Organic Compounds
and
• Synthetic Routes for Aromatic Compounds
have been taken from the
A-Level Chemistry for AQA: Year 2 Student Book,
so the page no.s found in the diagrams refer to pages
found in that textbook.
fl fl fl
