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25.4 Directing groups
Fichas del conjunto (23)
- 1Phenol can undergo an electrophilic substitution reaction with nitric acid to form what two isomers?2-nitrophenol
4-nitrophenol - 2Like phenol, many substituted aromatic compounds can undergo a second substitution - what is this called?Disubstitution
- 3What is the difference in the reaction of bromine reacting with benzene and with phenylamine?Bromine requires a halogen carrier catalyst to react with benzene whereas bromine will react rapidly with phenylamine
- 4Write out the reaction of phenylamine with bromine.
- 5In the phenylamine reaction what does the -NH2 group do to the ring?-NH2 group activates the ring as the aromatic ring reacts more readily with electrophiles
- 6How fast is the reaction between nitrobenzene and bromine?Slow
- 7What does the reaction between nitrobenzene and bromine require? Why?A halogen carrier catalyst and a high temperature
Benzene ring is less susceptible to electrophilic substitution than benzene itself - 8In the nitrobenzene example what does the -NO2 group do?-NO2 group deactivate the aromatic ring as the ring reacts less readily with electrophiles
- 9Where does the -NH2 group direct the second substituent to what positions?2 or 4
- 10Where does the -NO2 group direct the second substituent to which position?3
- 11Draw which groups would be ortho, meta and para.
- 12What is a directing effect?There are many different groups that can be attached to a benzene ring
Different groups can have a directing effect on any second substituent on the benzene ring - 13All 2- and 4- directing groups (ortho and para directors) are what type of groups and with the exception of what?Activating groups exception of the halogens
- 14What are all 3-directing groups (meta directors)?Deactivating groups
- 15-NH2 or -NHR -OH -OR -R, or -C6H5 -F, -Cl, -Br, -I2- and 4- directing (ortho-and-para directing)
- 16RCOR -COOR -SO3H -CHO -COOH -CN -NO2 -NR3^+3 directing (meta directing)
- 17Benzoic acid, C6H5COOH, can be nitrated using a mixture of nitric acid, HNO3, and sulfuric acid, H2SO4. Identify the mono-substituted organic product(s) of benzoic acid and write an equation for the reaction.
- 18Methylbenzene reacts more readily than benzene with bromine, forming approximately 67% of one mono-substituted product of methylbenzene and 33% of a second mono-substituted product. Draw the structures of both organic products and suggest which product is formed in the greatest percentage.
- 19Suggest a series of reactions that could be used to carry out the following synthesis. You should be able to carry out the reaction in two steps.
- 20Give an application of directing groups.Reaction of methylbenzene (toluene) with an excess of concentrated nitric acid and sulfuric acid
- 21At what 50°C toluene (methylbenzene) forms what?Monosubstituted product, 2-nitrotoluene
- 22Why is the product of this reaction less reactivethan toluene? However...Because the -NO2 group deactivates the benzene ring
However, if the temperature of the reaction mixture is increased to 70°C a disubstituted product, 2,4-dinitrotoluene is formed - 23What does the second - NO2 group do?Deactivates the benzene ring
Further reaction will produce 2,4,6-trinitrotoluene - TNT
This requires extreme conditions
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- Descripción
- A level (Module 6: Organic chemistry and analysis) Chemistry Fichas sobre 25.4 Directing groups, creado por Urvi B el 30/10/2018.
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- Urvi B
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