what is the amine functional group?
- NH2
what is the funtional group of an amide?
C=O
|
NH2
what do the terms primary secondary tertiary and quaternary amines refer to?
the number of alkyl groups attached to the Nitrogen
what is the name of CH3NH3+
methylammonium ion
what is the name of (CH3)4N+
tetramethylamonium ion
what does aliphatic mean?
any hydrocarbon chain without an aromatic compound
how to prepare aliphatic amines from haloalkanes?
- excess ammonia
- sealed copper tube (reflux)
write the equation of a haloalkane and ammonia?
haloalkane + ammonia –> amine + NH4+ +A-
what ratio would you have to mix the haloalkane:ammonia to get:
1) 2° amine
2) 3° amine
3) 4° amine
1) 2:1
2) 3:1
3) 4:1
why must the ammonia be in excess to produce a primary ammine (haloalkane + ammonia)
to avoid mutliple substitutions
how to prepare aliphatic amines from the reduction of nitriles (write eqns)?
1) nickel catalyst at 150°C
RCN + 2H2 –> RCH2NH2
2) reduced using LiAlH4 in dry ether
RCN + 4[H] –> RCH2NH2
how to prepare aromatic amines through reduction?
-reduction of nitrocompounds
- tin & conc HCl under reflux
how to prepare nitobenzene from benzene?
electrophilic addition:
H2SO4 + HNO3 –> H2NO3+ + HSO4-
H2NO3+ –> NO2+ + H2O
what are aromatic amines used for
making dyes
why are amines bases?
the lone pair on the N can accept a proton (can be protonated)
what changes the base strength of the amine?
the availability of the lone pair on the N atom - the more e- releasing alky groups on the N, to stronger the base (push e- towards the N)
how are many amines converted to alkylammonium salts
reacting them with acids - salts are more soluble as they are ionic
which one is the weaker base and why: methylamine or phenylamine?
phenyl amine is the weaker base as the benzene ring is an e- withdrawing group - the lone pair on the N interactes with benzenes e- cloud => less available lone pair to bond with proton
why can an amine act like a nucleophile?
lone pair on N
what is the chemical test for ammonium?
damp red litmus paper turns blue
what type of compound is formed in the reaction of chloroethane? what mechanism?
primary amine (1 alkyl group attached)
= nucleophilic substitution
what happens when a haloalkane reacts with excess 1° amine?
produces a 2° amine (no further subsitutions)
[similar principle for 2° and 3° amines]
what happens when a excess haloalkane reacts with limited amine?
leads to the prodcution of 1°, 2°, 3° amines and 4° ammonium salts
what are quaternary amine salts used for?
surfactants e.g. fabric conditioner
