27 - Amines, Amino acids and Polymers Flashcards
What are amines
derivatives of ammonia
one of more of the h’s on NH3 has been replaced by an organic group
aliphatic amine
the N atom is attached to atleast one straight or branched carbon chain
aromatic amine
the N atom is attached to an aromatic ring
how do you determine if a amine is primary / secondary / tertiary
depends on the number of alkyl groups attached to the N atom
why do amines act as bases
the N atom on ammonia has a lone pair of electrons that can accept protons
amine + dilute acid
–> ammonium salt
why can ammonia act as a nucleophile in a substitution reaction with a haloalkane
has a lone pair of e’s
reagents needed for
nucelophilic subs of ammonia with haloalkane
haloalkane
excess ammonia
in ethanol solvent
why is a ethanol solvent used in
nucelophilic subs of ammonia with haloalkane
prevents substitution of haloalkane by water to produce alcohols
why is ammonia used
nucelophilic subs of ammonia with haloalkane
reduces further substitution
of primary into seco into tert
consitions needed for
nucelophilic subs of ammonia with haloalkane
heat
conditions needed for
prepartaion of aromatic amines
reflux
reagents needed for
preparation of aromatic amines
tin (Sn)
conc. HCl
what is the reaction needed to form an aromatic amine and what type of reaction
nitrobenzene + 6reducing agent –> aromatic amine + 2H2O
reduction reaction
what functional groups do amino acids have
carboxylic acid
amine
what is an alpha amino acid
the amine and carboxylic functional groups are attached to the same carbon
what is the general formula of alpha amino acid
RCH(NH2)COOH
beta amino acid
amine is connected to the 3rd carbon
gamma amino acid
amine connected to 4th carbon
reactions of amine groups in amino acids
amino acid + acid –> salt
reactions of carboxylic acid groups in amino acids
amino acid + aq alkali –> salt + h2o
amino acid + alcohol –> ester + h20
reagents and conditions of esterfication of amino acids
cond = heat reagents = amino acid + conc. H2SO4 + excess alcohol
what is a zwitter ion
formed when the amine froup accepts a proton from the carboxylix group - forming an ion with both positive and negative charge
have no overall charge - cancels out
what is the isoelectric point
the pH which the zwitterion is formed
each amino acid has a unique isoelectric point
what happens if the amino acid is put in a solution with a pH greater than its isoelectric point
the AA behaves as an acid - loses a proton
what happens if the amino acid is put in a solution with a pH lower than its isoelectric point
the AA behaves as an base - gains a proton
optical isomerism
sterioisomers that are non-superimposable mirror images of each other = enantiomers
sterioisomerism
compounds with the same structural formula but different arrangement of atoms in space
chiral centre
c atom attached to 4 different atoms
what is condensation polymerisation
the joining of monomers with loss of a small molecule - usually water / hcl
condensation polymerisation to form polyesters
monomers are joined by ester linkages
can be made from:
- 1 monomer containing both a CA and alcohol group
- 2 monomers - 1 with both CA - 1 with both OH
dimerisation
2 molecules of the same compound react together
how does a polyester formed from its monomer
the CA group in 1 molecule
reacts with the OH group in another
to form an ester bond and h20
polymerisation of 1 monomer to form polester
(n-1)h20
polymerisation of 2 monomer to form polester
(2n-1)h20
condensation polymerisation to form polyamides
monomers joined by amide linkages
- 1 monomer with both CA (or acyl chloride) and amines
- 2 monomers
amino acid undergo condensation polymerisation to form
polypeptides - polyamides
how does a polamide formed from its monomer
CA group of one molecule reacts with amine group in another to form amide link
why are amides soluble
o in the OH group has a lone pair of electrons that can hydrogen bond with water molcules
N in amine group…
what is needed to hydrolyse polyamides and polyesters
hot aquesous alkali
hot aquoues acid
