Unit 4 Mechanisms Flashcards
Draw the mechanism for the acylation of benzene.
Arrow from benzene delocalised electron ring to carbocation.
Draw intermediate - must show horseshoe shape of delocalised ring (with + at centre) and the acyl group and H attached to benzene carbon at the open part of the horseshoe.
Arrow from C-H bond to horseshoe
What catalyst is used for the acylation of benzene? Write all the equations that involve the catalyst.
AlCl3
AlCl3 + CH3CClO==> AlCl4- + CH3C=O+
AlCl4- + H+ ==> AlCl3 + HCl
Draw the mechanism for the reaction between HCN and CH3CH2CHO. What type of mechanism is this?
Nucleophilic Addition
Arrow from lone pair on C of CN- to C with the C=O on the CH3CH2CHO molecule.
Arrow from C=O bond to O
Formation of intermediate with C-O-
Arrow from lone pair on O to H+ ion
Draw and name a mechanism for the nitration of benzene.
Electrophilic Substitution
Arrow from benzene delocalised electron ring to N of NO2+
Draw intermediate - must show horseshoe shape of delocalised ring (with + at centre) and the NO2 group and H attached to benzene carbon at the open part of the horseshoe.
Arrow from C-H bond to horseshoe
What are the reagents and what is the equation for the formation of the electrophile in the nitration of benzene?
Conc. H2SO4 and conc. HNO3
H2SO4 + HNO3 ==> HSO4- + H2O + NO2+
Draw and name the mechanism for the reaction between ethanoyl chloride and NH3. What is the name of the organic product?
Nucleophilic addition/elimination
Arrow from lone pair on N of NH3 to C that has C=O on ethanoyl chloride Arrow from C=O bond to O Formation of intermediate with N+ and O- Arrow from lone pair on O to C-O bond Arrow from C-Cl bind to Cl Arrow from N-H bond to N
Ethanamide
Other that NH3, what reagents react with ethanoyl chloride and what products are formed?
H2O ==> carboxylic acid + HCl
Alcohol ==> ester + HCl
Primary amine ==> substituted amide + NH4Cl
Draw and name the mechanism for the reduction of CH3COH with NaBH4 in acidic conditions. State what type of alcohol the product is.
Nucleophilic addition
Arrow from lone pair of H- (simification of NaBH4) to C with C=O
Arrow from C=O bond to O
Arrow from lone pair on O to H+(aq)
Primary alcohol
Why do aldehydes and asymetrical ketones produce race ages in nucleophilic addition reactions?
They have chiral carbon centres but are planar molecules, so the nucleophilic can attack from two different directions, decided by chance.
Does the product of a nucleophilic addition reaction with a symmetrical ketone rotate plane polarised light?
No. It has no chiral carbon centre as the alkyl groups on either side are the same.
Draw and name the mechanism for the reaction between NaOH and CH3CH2Br when conditions are aqueous and warm
Nucleophilic Substitution
Arrow from lone pair on OH- formed from NaOH
Arrow from C-Br bond to Br
Draw and name the mechanism for the reaction between NaOH and CH3CH2Br when in an ethanolic solution
Arrow from lone pair on OH- to H on C next to C with Br
Arrow from C-Br to neighbouring C-C bond.
Arrow from C-Br bond to Br
