What do you actually get if you react bromoethane with ammonia?,Making primary amines from nitriles

What do you actually get if you react bromoethane with ammonia? Whatever you do, you get a mixture of all of the products (including the various amines and their salts) shown on this page. To get mainly the quaternary ammonium salt, you can use a large excess of bromoethane. If you look at the reactions going on, each one needs additional bromoethane. If you provide enough, then the chances are that the reaction will go to completion, given enough time. On the other hand, if you use a very large excess of ammonia, the chances are always greatest that a bromoethane molecule will hit an ammonia molecule rather than one of the amines being formed. That will help to prevent the formation of secondary (etc) amines - although it won't stop it entirely. Making primary amines from nitriles Nitriles are compounds containing the -CN group, and can be reduced in various ways. Two possible methods are described here. Reducing nitriles using LiAlH4 One possible reducing agent is lithium tetrahydridoaluminate(III) - often just called lithium tetrahydridoaluminate or lithium aluminium hydride. The nitrile reacts with the lithium tetrahydridoaluminate in solution in ethoxyethane (diethyl ether, or just "ether") followed by treatment of the product of that reaction with a dilute acid. Overall, the carbon-nitrogen triple bond is reduced to give a primary amine. For example, with ethanenitrile you get ethylamine: Notice that this is a simplified equation - perfectly acceptable to UK A level examiners. [H] means "hydrogen from a reducing agent".
The reduction of nitriles using hydrogen and a metal catalyst The carbon-nitrogen triple bond in a nitrile can also be reduced by reaction with hydrogen gas in the presence of a variety of metal catalysts. Commonly quoted catalysts are palladium, platinum or nickel. The reaction will take place at a raised temperature and pressure. It is impossible to give exact details because it will vary from catalyst to catalyst. For example, ethanenitrile can be reduced to ethylamine by reaction with hydrogen in the presence of a palladium catalyst.