Haloalkanes and Haloarenes PPT Chemistry Class 12

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STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
PRIMARY 1° SECONDARY 2° TERTIARY 3°
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STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
PRIMARY 1° SECONDARY 2° TERTIARY 3°
STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
Names Based on original alkane with a prefix indicating halogens and position.
CH
3
CH
2
CH
2
Cl 1-chloropropane CH
3
CHClCH
3
2-chloropropane
CH
2
ClCHClCH
3
1,2-dichloropropane      CH
3
CBr(CH
3
)CH
3
2-bromo-2-methylpropane
PRIMARY 1° SECONDARY 2° TERTIARY 3°
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STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
PRIMARY 1° SECONDARY 2° TERTIARY 3°
STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
Names Based on original alkane with a prefix indicating halogens and position.
CH
3
CH
2
CH
2
Cl 1-chloropropane CH
3
CHClCH
3
2-chloropropane
CH
2
ClCHClCH
3
1,2-dichloropropane      CH
3
CBr(CH
3
)CH
3
2-bromo-2-methylpropane
PRIMARY 1° SECONDARY 2° TERTIARY 3°
STRUCTURAL ISOMERISM IN HALOGENOALKANES
Different structures are possible due to...
Different positions for the halogen and branching of the carbon chain
2-chlorobutane
2-chloro-2-methylpropane
1-chlorobutane
1-chloro-2-methylpropane
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STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
PRIMARY 1° SECONDARY 2° TERTIARY 3°
STRUCTURE  OF HALOGENOALKANES
Format Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
Halogenoalkanes - halogen is attached to an aliphatic skeleton - alkyl group
Haloarenes - halogen is attached directly to a benzene (aromatic) ring
Structural
difference Halogenoalkanes are classified according to the environment of the halogen
Names Based on original alkane with a prefix indicating halogens and position.
CH
3
CH
2
CH
2
Cl 1-chloropropane CH
3
CHClCH
3
2-chloropropane
CH
2
ClCHClCH
3
1,2-dichloropropane      CH
3
CBr(CH
3
)CH
3
2-bromo-2-methylpropane
PRIMARY 1° SECONDARY 2° TERTIARY 3°
STRUCTURAL ISOMERISM IN HALOGENOALKANES
Different structures are possible due to...
Different positions for the halogen and branching of the carbon chain
2-chlorobutane
2-chloro-2-methylpropane
1-chlorobutane
1-chloro-2-methylpropane
PHYSICAL PROPERTIES
Boiling point      Increases with molecular size due to increased van der Waals’ forces
M
r
bp / °C
chloroethane 64.5 13
1- chloropropane 78.5 47
1-bromopropane 124 71
Boiling point also increases for “straight” chain isomers.
Greater branching  =  lower inter-molecular forces
bp / °C
1-bromobutane CH
3
CH
2
CH
2
CH
2
Br 101
2-bromobutane CH
3
CH
2
CHBrCH
3
91
2-bromo -2-methylpropane (CH
3
)
3
CBr 73
Solubility Halogenoalkanes are soluble in organic solvents but insoluble in water