further substitution
What further substitution means in Chemistry A-Level, as defined for AQA.
Definitions of further substitution
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Reference: AQA
The sequence runs on because the amine still has a lone pair, so it attacks another halogenoalkane, through the secondary and tertiary amine to the quaternary ammonium salt.
The primary amine is a nucleophile and attacks more halogenoalkane, yielding a mixture of primary, secondary, tertiary amines and quaternary ammonium salts.
Any CH₃Cl formed is itself attacked, giving CH₂Cl₂, then CHCl₃ and finally CCl₄, so the product is always a mixture.
Topics that use further substitution
- Chlorination of alkanes (AQA A-Level)
- Nucleophilic properties (A-level only) (AQA A-Level)
- Preparation (A-level only) (AQA A-Level)
Related terms
- addition-elimination
- amide formation
- anhydride versus acyl chloride
- attack at a δ⁺ carbon
- attraction to negative surfaces
- azo dyes
- Bond enthalpy
- carbon chain length
Using further substitution in the exam
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