Aromatics Flashcards
What are aliphatics?
Carbon chains and rings (not benzene)
What are aromatics?
contain benzene rings
What is the molecular formula of benzene?
C6H6
What is the name of the Kekule cycle
cyclohexa-1,3,5triene
What are the pieces of evidence that Kekule model is incorrect?
- Benzene doesn’t decolourise bromine water
- All the C-C bonds are the same length
- benzene is 152 kJ less exothermic than expected
It is more stable than expected
what is the correct model of benzene?
Delocalised model
what is the structure and bonding of benzene?
- Each carbon forms, three bonds in a trigonal planar structure
- spare p orbital overlaps sideways
- form delocalised ring of electrons making benzene more stable
when will the root name of a compound benzene?
when the group attached to the Benzeze is;
- An alkyl group
- A halogen
- A nitro group
- A carboxylic acid
What is the other prefix of benzene?
phenyl
What are the steps in electrophilic substitution?
1: generate electrophile
2: electrophilic
3: regenerate the catalyst
What is the equation for the generation of the catalyst in the Nitration if benzene
H2SO4 + HNO3 > HSO4- + NO2 + H2O
What is the equation for the regeneration of the catalyst in Nitration
H+ + HSO4- > H2SO4
What are the uses of Nitrobenzene?
preparation of azo dyes
What is formed when a nitro group is reduced?
amine (NH2)
Why us methyl benzene more reactive than benzene?
- methyl group pushes electrons towards the benzene ring (positive inductive effect)
- theres a stronger attraction to the benzene ring
What is formed when benzene reacts with acyl chlorides?
phenyl ketone
What is the equation for generation of the electrophile in Friedel Crafts Acylation reactions
AlCl3 + RCOCl > RC+O + AlCl4-
What is the equation for regeneration of the catalyst in Acylation reactions
AlCl4- + H+ > AlCl3 + HCl
What are the conditions for reduction of nitrobenzene into an amine
conc HCl
Sn as a catalyst
reflux
