Aliya Hussain
Unit 14.4: making designer chemicals
Page
P5 2-23
P6 2-23
M6 23-25
D4 25-27
1
,Aliya Hussain
Preparation of compound without a carbonyl functional group
An alcohol from a halogenoalkane
The halogen is replaced by -OH and an alcohol is formed when a
halogenoalkane is heated under reflux with a solution of sodium or potassium
hydroxide. To prevent the loss of volatile substances from the mixture, heating
under reflux is done with a condenser placed vertically in the flask.
The solvent is usually a 50/50 mixture of ethanol and water, because
everything will dissolve in that. The halogenoalkane is water insoluble. The
halogenoalkane and sodium hydroxide solution would not mix if the solvent
was only water, and the reaction would only occur where the two layers met.
For example, using 1-bromopropane as a typical primary halogenoalkane:
figure 1
A substitution reaction occurs when the bromine (or another halogen) in the
halogenoalkane is simply replaced by a -OH group. Propan-1-ol is formed in
this example.
The mechanism:
Below is the mechanism for the reaction involving bromoethane:
Figure 2
This is an example of
nucleophilic substitution.
The mechanism is known as an SN2 reaction because it includes collision
between two species in the slow stage (in this case, the only step) of the
reaction.
Figure 3
Transition state
2
, Aliya Hussain
Formation of Propan-1-ol
Figure 4
https://www.youtube.com/watch?
v=cABdOpBP3hk
Reflux refers to an experimental method that involves heating a reaction
mixture to the boiling point temperature of the reaction solvent and inducing
the solvent to recondense back into the reaction flask using a condenser.
Many organic chemical reactions take very long to complete therefore, they go
through a reflux reaction because during the reflux process heat is applied and
the reaction speeds up.
Equipment
- Round bottom flask
- Bunsen burner
- Tripod stand
- Condenser
- Clamp stand
- Thermometer
- 1-bromopropane
- Ethanol solvent
- Sodium hydroxide
- Anti-bumping granules
Method
1. Set up the equipment before starting the experiment
2. In the round bottom flask 1-bromopropane (10ml), and Sodium
hydroxide (10ml)
3. Add anti- bumping granules to the flask to allow smooth boiling.
3
Unit 14.4: making designer chemicals
Page
P5 2-23
P6 2-23
M6 23-25
D4 25-27
1
,Aliya Hussain
Preparation of compound without a carbonyl functional group
An alcohol from a halogenoalkane
The halogen is replaced by -OH and an alcohol is formed when a
halogenoalkane is heated under reflux with a solution of sodium or potassium
hydroxide. To prevent the loss of volatile substances from the mixture, heating
under reflux is done with a condenser placed vertically in the flask.
The solvent is usually a 50/50 mixture of ethanol and water, because
everything will dissolve in that. The halogenoalkane is water insoluble. The
halogenoalkane and sodium hydroxide solution would not mix if the solvent
was only water, and the reaction would only occur where the two layers met.
For example, using 1-bromopropane as a typical primary halogenoalkane:
figure 1
A substitution reaction occurs when the bromine (or another halogen) in the
halogenoalkane is simply replaced by a -OH group. Propan-1-ol is formed in
this example.
The mechanism:
Below is the mechanism for the reaction involving bromoethane:
Figure 2
This is an example of
nucleophilic substitution.
The mechanism is known as an SN2 reaction because it includes collision
between two species in the slow stage (in this case, the only step) of the
reaction.
Figure 3
Transition state
2
, Aliya Hussain
Formation of Propan-1-ol
Figure 4
https://www.youtube.com/watch?
v=cABdOpBP3hk
Reflux refers to an experimental method that involves heating a reaction
mixture to the boiling point temperature of the reaction solvent and inducing
the solvent to recondense back into the reaction flask using a condenser.
Many organic chemical reactions take very long to complete therefore, they go
through a reflux reaction because during the reflux process heat is applied and
the reaction speeds up.
Equipment
- Round bottom flask
- Bunsen burner
- Tripod stand
- Condenser
- Clamp stand
- Thermometer
- 1-bromopropane
- Ethanol solvent
- Sodium hydroxide
- Anti-bumping granules
Method
1. Set up the equipment before starting the experiment
2. In the round bottom flask 1-bromopropane (10ml), and Sodium
hydroxide (10ml)
3. Add anti- bumping granules to the flask to allow smooth boiling.
3
