What are the methods used to prepare amines?

There are several methods for preparing amines. 

• Alkylation of ammonia: When ammonia reacts with an alkyl halide, it produces a mixture of primary, disubstituted, and trisubstituted amines. This results in a mixture of products. 
• Reductive amination of aldehydes or ketones: This involves their reduction in the presence of ammonia or primary/secondary amines and results in the formation of primary, secondary, or tertiary amines. When a ketone reacts with ammonia, and this is followed by catalytic or chemical reduction using sodium cyanoborohydride, it yields a primary amine. 
• In Gabriel synthesis, potassium phthalimide is reacted with an alkyl halide to produce an N‐alkyl phthalimide. This N‐alkyl phthalimide can be hydrolyzed by aqueous acids or bases into the primary amine.