CIE AS/A Level Chemistry 19.1 Primary amines Study Notes- 2025-2027 Syllabus
CIE AS/A Level Chemistry 19.1 Primary amines Study Notes – New Syllabus
CIE AS/A Level Chemistry 19.1 Primary amines Study Notes at IITian Academy focus on specific topic and type of questions asked in actual exam. Study Notes focus on AS/A Level Chemistry latest syllabus with Candidates should be able to:
recall the reactions by which amines can be produced:
(a) reaction of a halogenoalkane with NH₃ in ethanol heated under pressureClassification of amines will not be tested at AS Level.
Preparation of Amines
At AS Level, amines are prepared by a small number of key reactions. Classification of amines is not required and will not be tested.
(a) Reaction of a Halogenoalkane with Ammonia
Amines can be produced by reacting a halogenoalkane with ammonia dissolved in ethanol.
Conditions: heat in a sealed tube or under pressure.
General equation: \( \mathrm{R\!-\!X + NH_3 \rightarrow R\!-\!NH_2 + HX} \)
The reaction involves nucleophilic substitution, where ammonia acts as the nucleophile.
Example
State the reagents and conditions needed to prepare ethylamine from bromoethane.
▶️ Answer / Explanation
Bromoethane is reacted with ammonia dissolved in ethanol.
The mixture is heated under pressure in a sealed tube.
Example
Explain why ammonia must be used in excess in the reaction between a halogenoalkane and ammonia.
▶️ Answer / Explanation
Excess ammonia increases the chance of forming the amine.
It reduces further reactions between the halogenoalkane and the amine product.
This helps limit the formation of more substituted amines.