18B Organic Nitrogen

Question 1

what is functional group for amines?

Answer 1

R-NH2

Question 2

what is the functional group for amides?

Answer 2

R-C=ONH2

Question 3

de-esterification of esters

Answer 3

r - NH3 (aq)
c - reflux
p - amide

Question 4

nucleophilic addition of acyl chlorides

Answer 4

r - NH3 (aq) or conc. HCl
c - room temp
p - amide

Question 5

dehydration of carboxylic acids

Answer 5

r - NH3 (aq)
c - reflux
p - amide

Question 6

hydrolysis of amides

Answer 6

r - HCl (aq) or H2SO4 (aq)
c - reflux
p - carboxylic acid

Question 7

dehydration of amides

Answer 7

r - P4O10
c - reflux
p - nitrile

Question 8

hydrolysis of nitriles

Answer 8

r - HCl (aq) or NaOH (aq)
c - reflux
p - amide

Question 9

hoffman degradation of amides

Answer 9

r - Br2, NaOH (aq)
c - reflux
p - amine

Question 10

nucleophilic addition of amines

Answer 10

r - acylchloride
c - reflux
p - secondary amide

Question 11

nucleophilic substitution of halogenoalkanes (Sn) to form amines

Answer 11

r - conc. NH3 in ethanol
c - heat in a sealed tube
p - amine

Question 12

reduction of nitriles

Answer 12

r - LiAlH4
c - dry ether, reflux
p - amine

Question 13

neutralisation of amines

Answer 13

r - HCl (aq) or H+ (aq)
c - room temp
p - R-NH3+Cl-

Question 14

acylation of amines

Answer 14

r - RCOCl
c - room temp
p - secondary amide

Question 15

amines to amines acting as a base

Answer 15

r - water
c - room temp
p - R-NH3+ OH-

Question 16

ligand exchange of amines

Answer 16

r - [Cu(H2O)6]2+ (aq)
c - room temp
p - copper complex ion
[Cu-R-H20]2+

Question 17

secondary, tertiary amine formation from primary amine

Answer 17

r - excess CH3CH2Cl in ethanol
c - reflux
p - amine

Question 18

nucleophilic substitution of halogenoalkanes (Sn) to form nitriles

Answer 18

r - KCN, ethanol
c - reflux
p - nitrile

Question 19

hydrolysis of nitriles

Answer 19

r - HCl (aq)
c - reflux
p - amides

Question 20

how are hydroxynitriles formed from carbonyls?

Answer 20

r - KCN, H2SO4
c - reflux, pH 8 buffer
p - hydroxynitrile

Question 21

hydrolysis of dipeptides

Answer 21

r - conc. HCl (aq) , H2O
c - reflux
p - amino acid

Question 22

describe amphoteric behaviour

Answer 22

when something acts as both an acid and a base

Question 23

how are polyamides formed?

Answer 23

from the reaction between dicarboxylic acids and diamines
elimination of water results in long chain polymers
monomer units are linked with amide bonds

Question 24

what else can be used to make polyamides?

Answer 24

diacylchlorides

HCl is lost instead of water so should be done in fume cupboard

Question 25

define the term base

Answer 25

proton acceptor / lone pair donator

Question 26

what makes an organic compound more basic?

Answer 26

more alkyl groups inductively donating and stabilising the resulting ion

Question 27

why is ethanamide a weak base compared to an aliphatic primary amine?

Answer 27

delocalised lone pair creates resonance structure with C=O so it becomes less available for bonding

Question 28

what colour do amino acids turn in ninhydrin?

Answer 28

purple/pink/red

Question 29

explain why excess ammonia is needed in organic synthesis

Answer 29

product acts as nucleophile
further substitution occurs
excess NH3 reduces chance of further subsititution

Question 30

state the feature of an amine that allows it to act as a Bronsted-Lowry base

Answer 30

lone pair of e- on N

Question 31

why are aliphatic amines stronger bases?

Answer 31

alkyl groups that can push e- (inductive effect)

makes lone pairs more available

Question 32

why is ammonia a stronger base than phenylamine?

Answer 32

lone pair on N delocalises

less available for bonding

Question 33

what is meant by the term zwitterion

Answer 33

neutral molecule
has +NH3 and COO- groups
formed through proton transfer