Nucleophilic substitution

propylamine can be prepared by heating 1-bromopropane with excess ethanolic ammonia in a sealed container. outline the mechansim for this reaction.

silver ethanoate reacts with 1-bromobutane to give an ester.

has anyone any idea of what these mechansims look like or does anyone know a website where i can see it?

thank you!

also what to features of the propylamine molecule enable it to behave as a nucleophile.

Reply 1

john !!

The bromine is electronegative so the electron pair spend more time orbiting it. this makes the carbon slightly positive and makes it a target for nucleophiles. The NH(3) molecule has a lone pair on the nitrogen becuase only 3 of the 5 nitrogen outer shell electrons are being used in bonding. this makes ammonia a nucleophile (lone pair is attracted to the slightly positive carbon). the lone pair forces its way in (but does not bond), and one N-H bond in the ammonia breaks, as does the C-Br bond. The Br and H join and so do the remaining NH(2) and C(3)H(7) groups to make 1-propanamine and HBr.

Reply 2

john !!

G_S

silver ethanoate reacts with 1-bromobutane to give an ester.

Silver ethanoate is the ionic bond between a silver atom and a covelant organic molecule:

[Ag]+ [CH(3)COO]-

when this reacts with 1-bromobutane, the Ag+ and bromine atom break off to make AgBr, and the ethanoate ion bonds to the bromine.

You can see how the Ag and the Br break to make the oxygen and the carbon bond. (the bromine keeps the carbon's electron so the oxygen forms a dative covelant bond, although this doesn't matter really)

which I think is called propyl ethanoate (but wouldn't put money on it being since I was never really taught to name them!).

The code failed miserably so I took screenshots and theyre in the attachment (make sure you understand it, drawings are very important in understanding mechanisms!)

chem112212.JPG8.7KB

Reply 3

john !!

G_S

also what to features of the propylamine molecule enable it to behave as a nucleophile.

I'm not sure about the name but if you mean 1-propanamine (which we were taught to call the product of your first question),

the nitrogen still has a lone electron pair as it is only using three of its 5 outer shell electrons in bonding. the lone pair is negative and so it is attracted to positive centres, which fulfulls the criteria of a nucleophile.