What is benzene?
The simplest arene
Colourless, sweetly smelling and highly flammable
What is Kekule’s model of Benzene?
Three carbon-carbon double bonds in a cyclohexane structure
What are three pieces of evidence that disprove Kekule’s model?
The lack of reactivity of Benzene
The lengths of the carbon-carbon bonds
Hydrogenation enthalpies
What is the delocalised model of benzene?
Planar, cyclical
Each carbon uses 3/4 electrons in bonding
Each carbon has one electron in the p orbital, which overlap sideways
Forms a ring of electron density
The overlapping orbitals create the pi-system which creates a ring structure.
How do you name a substituted benzene compound?
The benzene ring is regarded as the parent chain
Position and name of the substitute groups are added as a prefix
Benzene is the suffix
How do you name a benzene ring attached to an alkyl chain longer than 7?
Phenyl is used as the prefix
What is a fused ring system?
Benzene rings joined together
Kekule’s model is used as the delocalisation will extend across all rings present.
Why is Benzene less reactive than alkenes?
They have a lower electron density and cannot induce a dipole in other molecules.
What type of reactions does benzene undergo?
Electrophilic substitution
A hydrogen atom in the benzene ring is replaced by another atom or group of atoms
What is a halogen carrier?
The catalyst needed for a halogenation reaction with Benzene
What are the reagents and conditions for the bromination of benzene?
Room temperature, room pressure
Bromine
Halogen carrier
What are the reagents and conditions for the chlorination of benzene?
Room temperature and pressure
Halogen carrier
Chlorine
What are the reagents and conditions for the nitration of benzene?
Concentrated sulfuric acid catalyst
Nitric acid
50 degrees, maintained in a water bath
What is alkylation reaction?
Substitution of a hydrogen in the benzene ring for an alkyl group
What are the reagents and conditions for an alkylation reaction with benzene?
Haloalkane
Halogen carrier catalyst
What is an acylation reaction?
Substituting an acyl group into the benzene ring
What are the reagents and conditions for an acylination reaction with chlorine?
Acyl chloride
Halogen carrier
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chapter 29
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chapter 519
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chapter 618
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chapter 716
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chapter 86
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chapter 920
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chapter 1010
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key definitions for organic chemistry15
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naming alkanes9
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isomerism6
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chapter 1217
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chapter 1318
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alcohols14
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chapter 1515
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acids and redox8
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practical techniques in organic chemistry2
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recycling polymers7
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mass spectroscopy4
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infrared spectroscopy6
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preparing a standard solution11
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chapter 1811
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chapter 1917
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Chapter 2634
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chapter 2231
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Chapter 2034
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Chapter 2113
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Chapter 2318
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Chapter 2437
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Chapter 2723
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Chapter 2518
