Final answer:
Primary amines are the major product in halogenoalkane to amine synthesis by preferring excess ammonia, controlled temperatures, and avoiding strong bases, which inhibits over-alkylation. Industrial processes may also use higher concentrations of alkane.
Step-by-step explanation:
To ensure that the primary amine is the major product when manufacturing amines from halogenoalkanes, there are specific conditions and methods that must be followed during the synthesis process.
Halogenoalkanes, also known as alkyl halides, can undergo nucleophilic substitution reactions where the halogen is replaced by an amine group. The primary aim is to avoid over-alkylation which can lead to secondary or tertiary amines.
Amine synthesis from halogenoalkanes involves using a large excess of ammonia. By favoring an excess of ammonia, the reaction tends to stop at the primary amine stage rather than substituting additional alkyl groups onto the nitrogen atom, which would lead to secondary and tertiary amines.
Additionally, controlled reaction temperatures and the avoidance of strong bases can minimize further substitution reactions. The industrial process might employ a higher concentration of alkane as well to reduce the concentration of potential secondary products.
For example, in the formation of chloroethane from ethene, the reaction with hydrogen chloride yields a monosubstituted alkyl halide, which then can react with excess ammonia to form ethylamine, a primary amine, preferentially over diethylamine or triethylamine.