1) An amine can be formed when 2-iodopentane is heated with ammonia in a sealed tube. This is an example of a nucleophilic substitution reaction.
a) Provide a full equation (using condensed formula) for this reaction. Name the reactants and the overall products too.
b) Name the organic product formed from this reaction and draw it’s displayed structure.
c) Provide a ‘curly arrow’ mechanism (in displayed formula) with an accompanying explanation for this process.
d) Describe a characteristic test (with the result that would be observed) to show the presence of the amine produced upon completion of the nucleophilic substitution reaction.
2) The amine produced in the above reaction forms a mixture of two optical isomers.
a) Draw the 3D structures of the two isomers of the amine product that you named and produced a drawing of in question 1 b).
b) Reference a different named example to explain the term optical isomer and draw the 3D structure of that example you named.
c) Describe (referencing the equipment used) how you can distinguish between the mixture of two optical isomers of this amine.
1) a)
CH3CH2CH2CH(CH3)I + NH3 ==> CH3CH2CH2CH(CH3)NH3 + I-
2- Iodopentane + Ammonia ==> I do not know + I do not know
b)
Displayed structure of products:
-----H--H--H--CH3-H
-----I----I----I-----I ---I
H - C - C - C - C - N - H -------- + -- (What is the displayed structure of I-)
------I---I----I-----I ---I
-----H--H---H---H --H
Is only one of the products organic? Which one or ones are organic?
c)?
d)?
2)?
a) The full equation for the reaction is: 2-iodopentane + ammonia → pentylamine + ammonium iodide
b) The organic product formed from this reaction is pentylamine, which has the following displayed structure:
H
|
H - C - C - C - C - C - NH2
|
I
c) The curly arrow mechanism for this process involves the nucleophilic attack of the ammonia molecule on the carbon atom attached to iodine in 2-iodopentane. This leads to the formation of a new carbon-nitrogen bond and the elimination of iodide ion. The mechanism can be represented as follows:
Step 1: Nucleophilic attack
H H
| |
C - C - C - C - C - NH2
| |
I H
Step 2: Bond formation and elimination
H
|
H - C - C - C - C - C - NH2
|
H
Explanation: The ammonia molecule acts as a nucleophile, attacking the carbon atom attached to iodine. The bond between carbon and iodine breaks, resulting in the formation of a new carbon-nitrogen bond. The iodide ion is eliminated as a leaving group.
d) To test for the presence of the amine produced, you can perform the Hinsberg test. In this test, mix the amine with benzene sulfonic acid and potassium hydroxide. If the amine is present, it forms a water-soluble sulfonamide precipitate. This can be observed as a white precipitate upon addition of the reagents.