Amines 1 Flashcards
important compounds that have amino groups:
i)ephedrine/adrenaline
ii)novocain
iii)benadryl
iv)quartnernary ammonium salts
v)diazonium salts
i) ephedrine and adrenaline help are used to increase blood pressure. both have secondary amino group
ii) novocain is used as an anaesthetic in dentistry, synthetic amini cpd
iii)benadryl is an anti-histaminic drug having tertiary amino group
iv)quarternary ammonium salts are used as surfactants
v) diazonium salts are intermediates in the preparation of a variety of aromatic compounds including dyes.
structure of nitro group
Amines can be considered as derivatives of ammonia,
obtained by replacement of one, two or all the three
hydrogen atoms by alkyl and/or aryl groups.
The nitorgen atom is sp3 hybridised and has pyrimidal geometry.
why is angle of amines less than normal tetrahedral angle? is it the same case in trimethylamine
the angle of amines is 107* because of lp-bp repulsion
in trimethyl amines the angle is slightly larger due to the repulsion between bulky methyl groups
classification of amines
it can be classified into primary, secondary and tertiary amines.
Amines are said to be
‘simple’ when all the alkyl or aryl groups are the same, and ‘mixed’
when they are different.
naming of amines
i) common
ii)iupac
i) named as alkyl amine. di tri used to indicate more than 1 alkyl group
ii) named as alkanamine. locants used to specify position of nh2 group
the substituents attached to N directly and indicated with the help of N
C6H5-NH2 is called as aniline or benzenamine
odour and physical state and colour of amines
The lower aliphatic amines are gases with fishy odour.
Primary amines
with three or more carbon atoms are liquid and still higher ones are
solid.
Aniline and other arylamines are usually colourless (brown) but get
coloured on storage due to atmospheric oxidation.
solubility of amines in water
Lower aliphatic amines are soluble in water because they can form intermolecular
hydrogen bonds with water molecules.
However, solubility decreases with increase in molar mass of amines due to increase in size of the hydrophobic alkyl part.
Higher amines are essentially insoluble in water.
is aniline soluble in water
aniline is insoluble in water due to the large hydrocarbon part which is hydrophobic in nature.
why is butan-1-ol more soluble in water compared to butan-1-amine?
why are alcs more soluble in water than amines
alcohols are more polar than amines and form
stronger intermolecular hydrogen bonds with water than amines.
This is due the difference of electronegatvitiy of O and N.
electronegativity of nitrogen of amine and oxygen of alcohol is 3.0 and 3.5
describe the nature of intermolecular bonding within amines?
Primary and secondary amines are engaged in intermolecular
association due to hydrogen bonding between nitrogen of one and
hydrogen of another molecule. This intermolecular association is more
in primary amines than in secondary amines as there are two hydrogen
atoms available for hydrogen bond formation in it.
tertiary amines do not form hydrogen bonds. why
Tertiary amines do
not have intermolecular association due to the absence of hydrogen
atom,bonded to the nitrogen, available for hydrogen bond formation.
boiling points of isomeric amines
primary> secondary> tertiary
bpts of organic cpds
alcohol > 1o > 2o > 3o amine > hydrocarbon
