topic 18 arenes Flashcards
(21 cards)
how kekule thought that benzenes were like
like cylohexatriene with 3 double bonds and 3 single bonds that are alternating
what differs benzene from cyclohexatriene
resonance hybrid
explain resonance of benzene
ring od delocalised electrons
outer electron from p orbitals of each carbon atom is delocalised into the centre to form a central ring. This overlap of electrons result in the formation of pi bonds
why the real structure of benzene is more stable
due to delocalised electron ring
how x ray diffraction differs benzene and cyclohexatriene
shows that in benzene all of the bonds have the same bond length
intemediate length of bonds
how infrared data differs benzene and cyclohexatriene
cyclohexatriene has two peaks while benzene has only one
why enthalpy change of hydrogenetion of benzene is less than expected
it is less exothermic as benzene is more stable than cyclohexatriene
more energy is required to break the bonds
condition of free radicalic substitution of benzenes
UV light
bromination of benzenes catalyst
2Fe+ 3Br2 —> 2FeBr3
FeBr3 +Br2 —> FeBr4^- +Br^+
chlorination of benzenes catalyst
AlCl3 + Cl2 —> AlCl4^- +Cl^+
nitration of benzenes catalyst + conditions
H2SO4 + HNO3 –> H2NO3^+ + HSO4^-
H2NO3^+ –> NO2^+ + H2O
condition: temp 60 C
alkylation of benzenes catalyst
AlCl3
acylation of benzenes catalyst
AlCl3
sulfonation of benzenes catalyst + condition
oleum or
fuming H2SO4
condition: gentle heating
benzoic acid + alcohol
benxzoic acid ester
benzoic acid+ nitrile
benzoic acid amide
benzoic acid + PCl5
Benzoyl chloride
benzoyl chloride + nitrile
benzoic acid amide
benzoyl chloride + alcohol
benzoic acid ester
why phenol is more reactive than benzene
donation of lp electron of oxygen into the ring increases the electron density around the ring making it more susceptible to electrophilic attack
