Organic synthesis aromatic functional groups

Question 1

Why must chlorination reaction with benzene be carried out under anhydrous conditions?

Answer 1

AlCl3 reacts VIOLENTLY with water

Question 2

Halogen carriers

Answer 2

substances that are able to REMOVE halogen atoms from molecules

Question 3

How is Br+ electrophile generated in bromination of benzene using FeBr3 as a catalyst

Answer 3

• Fe + Br2 –> 2FeBr3

* FeBr3 interacts with Br2 –> Br- is removed from Br2 and added to FeBr3 –> FeBr4^- and Br^+ electrophile is generated

Question 4

Nitrating mixture

Answer 4

c.HNO3 + c.H2SO4

Question 5

What happens when the nitration of benzene occurs at temperatures > 55 degrees? and why is this dangerous

Answer 5

Further substitution of NO2 groups in the benzene ring (DANGEROUSLY EXPLOSIVE)

Question 6

Why are Friedel-Crafts reactions useful?

Answer 6

adding C and building up side chains

Question 7

How is the electrophile NO2+ (charge of 1 FUCK YOU BRAIN SCAPE) generated?

Answer 7

in the nitration mixture

Question 8

What happens when the strong acid Benzenesulfonic acid is in alkaline solution?

Answer 8

forms a salt

Question 9

What effect does nitration have on benzene ?

Answer 9

modify chromophore

this changes wavelength of light that the chromophore absorbs and thereby changes the colour of the molecule

Question 10

What effect does sulfonation reactions

Answer 10

Modifies aromatic compounds to form strong acids that can then react with sodium hydroxide (bases) producing *water soluble aromatic compounds(salt)

Question 11

How can a dye be made more soluble?

Answer 11

add sulfonic acid group

Question 12

Why are diazonmium compounds unstable? and how can we make them more stable?

Answer 12

N2(g) easily lost

attach diazonium group to benzene ring so that the e- in the N≡N will become part of the delocalised system in benzene

Question 13

Diazotisation

Answer 13

A reaction in which an amine group is converted into a diazonium SALT

Question 14

Diazotisation reagents and conditions

Answer 14

dissolve aromatic amine in DILUTE HCL
+ add COLD NaNO2 –> HNO2 + H^+
carry out reaction BELOW < 5 degrees in ice bath

Question 15

Coupling agent

Answer 15

a compound CONTAINING a relatively REACTIVE benzene ring

Question 16

why do coupling agents generally have phenol or amino groups attached?

Answer 16

phenols and amino groups have lone pairs of e^- that increase the electron density on the benzene ring and thereby increasing reactivity towards electrophiles