Chapter 17 Reactions Flashcards
Benzene to bromobenzene and HBr
Electrophilic Aromatic Substitution (EAS), Halogenation, Br2, and FeBr3 catalyst
Benzene to nitrobenzene and water
EAS, Nitration, HNO3 in H2SO4
Benzene to benzenesulfonic acid
EAS, SO3 in H2SO4, H3O+, heat
Benzene to Tert-butylbenzene and HCl
Friedel-Crafts alkylation, (CH3)3C-Cl, in AlCl3
Benzene+CH3-CH2-C=OCl to propriophenone
Friedel-Crafts acylation 1) AlCl3 2)H2O
Benzene reacted with an alkyl halide (like t-butyl chloride) and AlCl3
t-butyl benzene +HCl. FC alkylation
Benzene reacted with an acyl group (like propanoyl chloride) and AlCl3+H2O
Propriophenone+HCl. FC acylation.
Draw the mechanism for Fridel-Crafts Alkylation
Step 1. formation of carbocation via halogen of alkyl halide attacking lewis acid (AlCl3)
Step 2. electrophilic attack form sigma complex.
step 3. loss of proton regenerates aromaticity. and give alkylated product.
Draw the mechanism for Fridel-crafts acylation
Step 1. formation of acylium ion via removal of halogen by AlCl3.
Step 2. electrophillic attack by pi electrons of benzene on acylium ion forms sigma complex.
Step 3. loss of proton to Cl of AlCl3 regenerates the aromatic system.
Step 4. O attacks AlCl3, which must later be removed via hydrolysis.
What process and reactants are you when making an alkylbenzene that can’t be made via FC alkylation?
FC aclylation and desired acyl halide in alcl3 is used to make the correspoding acylbenzene. This is followed by Clemmensen Reduction using Zn(Hg) and aqHCl to remove the oxygen (reduce) it to the desired alkylbenzene.
When is the Benzyne mechamism used?
when a halobenzene is unactivated towards NAS (it has no deactivating substituents besides the halogen.)
What is the mix of meta and para products in an NAS reaction when the reactant is a toulene a result of?
attack by the nucleophile at either end of the triple bond.
