Flashcards in Benzene Deck (7)
Elec sub of benzene with nitric acid
H atom on benzene ring is replaced by a NO2+ electrophile (produced by HN03 +H2SO4) produces Water and H2SO4- ion .
Catalyst ; H2SO4
Heated to 50 DC for good rate of reaction. (if higher then further sub reactions will occur leading to production of dinitrobenzene)
catalyst is regenerated by reaction between H+ and HSO4- ion.
Halogenation of benzene , what are the conditions necessary for all halogenation reactions of benzene?
A halogen carrier catalyst is needed - common carriers include ; FeBr (Bromination) , FeCL3 (chlorination) , AlCL3 (for Chlorination, alkylation, acylation)
Bromination of benzene
electrophile ; AlBr3 --- Br+ Bromonium ion.
Why? Cuz Benzene is too stable to react with a non-polar Br2 molecule.
product ; Bromobenzene + H^+
Chlorination of benzene?
Electrophile; AlCl3/ FeCl3 --- Cl+ ion
Product : Chlorobenzene + HCL
Alkylation of benzene
sub of H atom on benzene by an alkyl group- occrs by reacting benzene with a haloalkane in presence of AlCl3
e.g ; benzene + C2H5Cl = Ethylbenzene +HCL
Acylation of benzene
sub of H atom on benzene by acyl chloride using catalyst AlCl3
benzene + Ethanol chloride = Phenylethanone + HCL