Amines

Question 1

How is paracetomol formed?

Answer 1

-phenol is nitrated with sulfuric acid + sodium nitrate
-4-nitrophenol and 2-nitrophenol formed
i-somers seperated by fractional distilation due to different melting points
-4-nitrophenol reduced to 4-aminophenol using sodium tetrahydridoborate in alkaline
4-aminophenol reacts with ethannoic anhydride

Question 2

what colour is formed when amines reacts with TM?

Answer 2

purple

Question 3

what colour is formed when an amino acid reacts with ninhydrin?

Answer 3

deep blue/purple

Question 4

how to form phenylamine from nitrobenzene

Answer 4

• heat under reflux

- tin(iron) + conc HCl

Question 5

explain how to form a diazonium ion

Answer 5

nitrous acid in situ
use sodium nitrite and dilute HCl
must be 5 degrees or lower otherwise phenol formed
stable upto 10 degrees due to ring of delocalised electrons
2H20 produced
N triple bond NCl- is diazonium

Question 6

how to form an azo dye?

Answer 6

react in cold alkaline with phenol
HCl produced
N=N bond
colour produced to delocalised systems that spread across entire molecule

Question 7

what is a zwitterion ion?

Answer 7

an amino acid in neutral conditons with a positive and negative end
this explains the high melting point

Question 8

what happens to amino acid in alkaline?

Answer 8

loses a proton

Question 9

what happens to amino acids in acid solution?

Answer 9

gains a proton

Question 10

how are amino acids joined together?

Answer 10

through condensation reaction
OH (COOH) from one amino acid and H (NH2) from other
forms a peptide bond

Question 11

explain TLC (thin layer chromotography)

Answer 11

dissolved in suitable solvent
spot of solution placed 2cm above plate
spot of knwon amino acid also placed at same level
plate dippled in suitable eluent making sure spots are above eluent in a sealed container
eleuent drawn by capillary
plate is left to allow eleuent to rise
plate removed
sprayed with ninhydrin and heated
height of unknown compared to known