Page 1 - Microsoft Word - Lesson note-1(haloalkanes and haloarenes)

SUBJECT-CHEMISTRY

CHAPTER-HALOALKANES AND HALOARENES.

KEY NOTES:

Method so preparation of haloalkanes:
(a) From alcohol.
ZnCl
R OH NX  R X H O




2
2


R OH NaBr H SO  R Br NaHSO  H O



2
4
4
2



R OH PX  R X H PO

3
3
3


R OH PCl  R Cl POCl  HCl


3
5
2 X
RedP/
R OH R X


[X 2 Br ,I ] 2 2
R OH SOCl  R Cl SO   HCl




2
2
(b) From hydrocarbons:
(i)By free radical halogenations of alkanes:
Cl
2 .uv light
CH CH CH CH  CH CH CH CH Cl CH CH CHClCH

5
3
3
2
2
2
2
2
3
2
3
orheat
(ii) from alkene:

Markonikov's
R.CH CH  H X  R CH CH




2
3
rule
|
X
benzoyl peroxides

R CH CH  H Br  R CH CH  Br



2
2
2
antimarkonikov's rule

(c) Halide exchange:
dry acetone

R X NaI  R I NaX (X = Cl, Br) [finkelstain reaction]



Agf or Hg
2 2 F or CoF or SbF
R X  R F [swarts rection]


2
3
Chemical properties:
(i) Nucleophilic substitution: