Alcoholic Ammonia vs Aqueous for Treating Haloalkanes

[ambuj123]

Why do we use alcoholic Ammonia not Ammonia only or aqueous ammonia while using it to treat haloalkanes to form primary,secondary or tertiary amines.
same for treatment of haloalkanes with alcoholic silver cyanide to form alkyl iso cyanide.why don't we use aqueos AgCN
Thanx

 

[movies]

Probably because water is a pretty good nucleophile in its own right. Using alcohol solvents limits the amount of undesired alcohol formation.

 

[chem_tr]

I agree with Movies, and want to add something more; haloalkanes don't like water at all, it cannot be dissolved in it. Alcohol is a good solvent to solvatize haloalkanes, providing enough particles to react with each other.

Ammonia is a base, and if you trap it in a solvent, it can "live" for a prolonged period, sometimes enough to cause something in the solution.

 

[GCT]

chem tr seems to have the main point, read up on protic polar solvents, this subject is probably under the SN2, elimination reaction introduction chapter.

 

[ambuj123]

THanx

Thank you for the help