Amines Flashcards
What are the uses of quaternary ammonium salts and why are they used?
-Cleaning products e.g. shampoo, detergents…
-As the tail is attracted to dirt and the head is attracted to water allowing grease to mix
Are amines basic or acidic and why?
They are basic as they have a lone pair to accept a H+
What does the strength of amine base depend on?
The availability of the lone pair (if it has a higher electron density it is more readily available) -> which is dependent on the group
What does amine act as? (in terms of mechanisms)
Nucleophile
What type of base is a amine? (BL or LB)
Both as it can accept a H+ (BL)
It is an electron pair donor (LB)
What types of amine are formed when amine reacts with halogenoalkanes?
1°,2°,3° & 4°
What conditions are needed when reducing Nitriles?
High pressure and temperature
Non aqueous solvent (dry ether)
What catalyst is needed when reducing Nitriles?
-Nickel
-LiAlH4
-Platinum
What is the Nitrile reacted with when reduced?
Hydrogen
What are aromatic amines used for?
-Dyes
-Pharmaceuticals
What conditions are needed to form aromatic amines?
Reflux
What catalysts needed to form aromatic amines?
HCl
Tin
What are the steps in forming an aromatic amine?
1) Nitrobenzene heated with HCl under reflux -> forms a salt
2) Salt is reacted with a base to remove the +-
What are the ways Aliphatic amines produced?
1) Halogenialkanes with excess ammonia
2) Reducing Nitriles
What is an amide?
when a carbonyl is attached to NH2 or NHR (N-substituted amide)
Order these from most to least alkaline Ammonia ethylamine phenylamine?
ethylamine > Ammonia > phenylamine
(Phenylamine contains a phenyl group attached to the amine. Phenyl groups have a delocalised system of electrons as a result of p orbitals from the 6 adjacent carbon atoms overlapping and “merging” together to form a 9very stable) delocalised pi bond with 6 electrons. The lone pair of the nitrogen atom in the amine group is “drawn in” towards this delocalisation and this interaction makes the lone pair less available to bond to an incoming H+ ion. In comparison, ethylamine has no delocalisation in the molecule. In fact, there is actually a positive inductive effect contributed from the alkyl groups of the ethylamine which pushes the lone pair away from the N atom and makes the lone pair more available to bond to an H+ ion. The availability of a lone pair of electrons on a base determines its strength as it is these electrons that will “mop up” H+ ions in solution and hence increase pH towards more alkaline conditions. Therefore, phenylamine is a weaker base than ethylamine because its lone pair is less available.)
