Benzene.................................

Benzene powerpoint

1. 23 April 2001 Miles Selvidge 1
Benzene CBenzene C
66HH
66
02
-
3

2. 23 April 2001 Miles Selvidge 2
Table of ContentsTable of Contents

StatsStats

StructureStructure

BondingBonding

Electronic PropertiesElectronic Properties

ReactionsReactions

NomenclatureNomenclature

IndustryIndustry

Harmful EffectsHarmful Effects

3. 23 April 2001 Miles Selvidge 3
StatisticsStatistics

Discovered by Michael Discovered by Michael
Faraday - 1825Faraday - 1825

Most Basic Aromatic Most Basic Aromatic
MoleculeMolecule

Colorless LiquidColorless Liquid

Boiling Point: 80.08Boiling Point: 80.08
oo
CC

Melting Point: 5.48Melting Point: 5.48
oo
CC

Density: .880 g/cmDensity: .880 g/cm
33

4. 23 April 2001 Miles Selvidge 4
Statistics Statistics -- continuedcontinued

Insoluble in WaterInsoluble in Water

Soluble in Oils & FatsSoluble in Oils & Fats

Explosive VaporsExplosive Vapors

Flammable LiquidFlammable Liquid

5. 23 April 2001 Miles Selvidge 5
StructureStructure

Flat StructureFlat Structure

Carbon Atoms are spCarbon Atoms are sp
2 2
HybridizedHybridized

Carbon has Triangular Carbon has Triangular
Planar GeometryPlanar Geometry

6. 23 April 2001 Miles Selvidge 6
BondingBonding

Sigma and pi Bonding Sigma and pi Bonding
between Carbon between Carbon
atomsatoms

Has Resonance Has Resonance
Structure ==>Structure ==>

Actual Bonds are All Actual Bonds are All
Intermediate LengthIntermediate Length

Increased StabilityIncreased Stability

7. 23 April 2001 Miles Selvidge 7
Electronic PropertiesElectronic Properties

The Six Electrons in the The Six Electrons in the pipi
Bonds are Loosely Held Bonds are Loosely Held
Compared to the Electrons Compared to the Electrons
in the in the sigmasigma Bonds Bonds

Those Six Electrons are Those Six Electrons are
DelocalizedDelocalized
•This causes a cloud of This causes a cloud of
electrons above and electrons above and
below the plane of the below the plane of the
benzene moleculebenzene molecule

8. 23 April 2001 Miles Selvidge 8
ReactionsReactions

The Resonance Structures of Benzene The Resonance Structures of Benzene
Increase its StabilityIncrease its Stability
•Resist Addition Reactions Because That Would Resist Addition Reactions Because That Would
Destroy the Ring StructureDestroy the Ring Structure
•Often Undergoes Substitution ReactionsOften Undergoes Substitution Reactions

Benzene Serves as a Source of Electrons for Benzene Serves as a Source of Electrons for
Electrophilic ReagentsElectrophilic Reagents

9. 23 April 2001 Miles Selvidge 9
Reactions Reactions - Types of Substitutions- Types of Substitutions
Nitration:Nitration: C C
66HH
66 + HNO + HNO
33 C C
66HH
66NONO
22 + H + H
22OO

Halogenation:Halogenation: Carbon Replaced by Halogen Carbon Replaced by Halogen

Sulfonation:Sulfonation: Carbon Replaced by Sulfer Carbon Replaced by Sulfer

Friedel-crafts:Friedel-crafts: Acyl group (RCO-) Attaches to Acyl group (RCO-) Attaches to
Ring to Make a KeytoneRing to Make a Keytone
Nitrobenzene

10. 23 April 2001 Miles Selvidge 10
Nomenclature of BenzeneNomenclature of Benzene

When Substituent When Substituent
Takes its Place in the Takes its Place in the
Ring the New Ring the New
Molecule’s name is Molecule’s name is
the the prefixprefix -benzene -benzene

Ex: ChlorobenzeneEx: Chlorobenzene

11. 23 April 2001 Miles Selvidge 11
NomenclatureNomenclature - Continued- Continued

If More Than One Group Attaches to If More Than One Group Attaches to
Benzene then Positions Must be IndicatedBenzene then Positions Must be Indicated

Ortho (Ortho () = One Space) = One Space

Meta (m) = Two SpacesMeta (m) = Two Spaces

Para (p) = Three SpacesPara (p) = Three Spaces
CH
3
NO
2
NO
2
Cl
I
Br
-Nitrotoluene
M-Chloronitrobenzene
p-Bromoiodobenzene

12. 23 April 2001 Miles Selvidge 12
Nomenclature Nomenclature - continued- continued

-Nitrotoluene -Nitrotoluene

m-Chloronitrobenzenem-Chloronitrobenzene

p-Bromoiodobenzenep-Bromoiodobenzene

13. 23 April 2001 Miles Selvidge 13
Nomenclature Nomenclature - continued- continued

If 3 or More Groups AttachIf 3 or More Groups Attach
•Numbers are Used to Indicate PositionsNumbers are Used to Indicate Positions
•2-Chloro-4-nitrophenol2-Chloro-4-nitrophenol
OH
Cl
NO
2
1
2
3
4
5
6

14. 23 April 2001 Miles Selvidge 14
IndustryIndustry

Made from Coal Tar (a liquid left over when Made from Coal Tar (a liquid left over when
coal is heated) and Petroleumcoal is heated) and Petroleum

Used as a Source for Almost all Aromatic Used as a Source for Almost all Aromatic
CompoundsCompounds
•Make Complicated Aromatic Compounds by Make Complicated Aromatic Compounds by
Taking Benzene and Add on Other Rings Piece Taking Benzene and Add on Other Rings Piece
by Pieceby Piece

15. 23 April 2001 Miles Selvidge 15
Industry Industry - continued- continued

Solvent for:Solvent for:
•Sulfur, Phosphorus and IodineSulfur, Phosphorus and Iodine
•GumsGums
•Fats, Waxes and ResinsFats, Waxes and Resins
•Simple Organic CompoundsSimple Organic Compounds
–One of the Most Commonly Used Solvents in Organic ChemistryOne of the Most Commonly Used Solvents in Organic Chemistry

16. 23 April 2001 Miles Selvidge 16
Industry Industry - continued- continued

Aniline: Aniline:
•Dye (Aniline Oil)Dye (Aniline Oil)
•PlasticsPlastics
•Drugs (Sulfanilamide) Drugs (Sulfanilamide)
•ExplosivesExplosives

Phenol:Phenol:
•DisinfectantDisinfectant
•Antiseptic (Diluted)Antiseptic (Diluted)
•InsecticideInsecticide
•ExplosivesExplosives
•DetergentDetergent
•Raw Material for AspirinRaw Material for Aspirin
 Can Make Aniline and PhenolCan Make Aniline and Phenol

17. 23 April 2001 Miles Selvidge 17
Industry Industry - continued- continued

Makes Toluene, a component of TNT Makes Toluene, a component of TNT
(Trinitrotoluene)(Trinitrotoluene)

Makes Tear GasMakes Tear Gas

Makes AcetoneMakes Acetone

18. 23 April 2001 Miles Selvidge 18
Toxic NatureToxic Nature

Carcinogen -- Causes LeukemiaCarcinogen -- Causes Leukemia

Makes DioxinsMakes Dioxins
•Two Phenols Combine and Cl Connects to Make Two Phenols Combine and Cl Connects to Make
Chlorinated Dibenzo-p-dioxinChlorinated Dibenzo-p-dioxin

Does not Dissolve in Water, but does in Oils Does not Dissolve in Water, but does in Oils
and Fatsand Fats
•Accumulates in the Food WebAccumulates in the Food Web

Mimics HormonesMimics Hormones
•Disrupts Normal Functions and GrowthDisrupts Normal Functions and Growth