Organic halides

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Organic halides
By
Dr/ Amani S. Awaad Professor of pharmacognosy,
King Saud University
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Organic Halides
Source important 1-Rare in nature produced by
micro. Algi. (Ab. Th.) 2-used (herbicides,
detergent , insecticide) 3-intermediat for
synthesis.
Classes Names
According to hydrocarbon gp.
1-Alkyl halides( R-X)
2-Allylic halides
3-Vinylic halides
4-Benzylic halides
5-Aryl halides
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1-Alkyl halides( R-X)
1?,2? 3?(no H attached)
CH3Cl CH3CH2CH2Br
CH3CHFCH3
Comm. Methyl Chloride n- propyl
bromide isopropyl fluoride IUPAC
Chloromethane 1-Bromo propane
2-fluoropropane Class 1?
1?
2?
Co. Cyclo hexyl iodide Methyl cyclopentyl
chloride t-Butyl romide IUPAC
idocyclohexane 1-Chloro-1-methylcyclopentane
2-bromo2-methylpropane Class 2?
3?
3?
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3-Vinylic halides
2-Allylic halides
CC-C- X
CC-X
CH2CHBr
CH3CHCHCH2Cl Comm. Viynlyl
bromide Allyl
chloride IUPAC 3-Bromo-1-propene
1-Chloro-2-butene
3-Chlorocyclopentene 3-Bromocyclohexene
4-Benzylic halides
Ar-C-X ( halogen one carbon away from aromatic
ring)
Benzyl Chloride
Diphenyl methylbromide
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5-Aryl halides
Ar-X (X directly attached to ? )
Chlorobenzene
p-Bromo toluene
Physical Properties
sol. In organic solvent (in sol. In H2O) BP. ?
with ? Mwt.( Straight chain ? branched) In
series of halides Bp. F ltCl ltBr ltI
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Preparation Of Halogen compounds
1Direct Halogenation of hydrocarbons
a) Halogenation of alkanes(alkyl halides)
eg,
b)Halogenation of alkenes (allyl halides)
c)Halogenation of benzene(benzyl halides)
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d) Halogenation of aromatic ring (aryl halides)
2Addition of HX to unsaturated hydrocarbons
a)To alkenes (alkyl halides)
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eg.
3
b)To alkynes (Vinyl halides)
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3 Conversion of alcohol (alkyl halides)
ZnCl2
ZnCl2
1? 2? need catalyst 3? without catalyst
ZnCl2
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Reactions of organic halides
1 Nucleophilic substitution reaction
a) RX NaOH / H2O(or(KOH/H2O) ROH
(alc.)
b) RXKCN / NaCN R-CN
(nitrile)
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c) RX NaOR / alcohol( or KOR) ROR
(ether)
d) RX R/-CC-Na( liq.NH3) R/-CC-R
(alky.)
e) RX R'NH2/liq.NH3 RNHR'
(amine)
g) RX NaI R-I
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2Elimination reactions
3Reaction of Gregnared reagent
R-X Mg R-X -Mg Ar-X
Mg Ar-X Mg
4Reduction of alkyl halides(by metal and acid)