Methods Of Preparation
Chapter Name : Haloalkanes And Haloarenes |
Sub Topic Code : 102_12_10_04_02 |
Topic Name : Methods Of Preparation |
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Sub Topic Name : From Hydrocarbons |
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Introduction
1.Free radical chlorination or bromination of alkanes gives a complex mixture of isomeric mono- and poly haloalkanes, which is difficult to separate as pure compounds. 2.Consequently, the yield of any one compound is low 3.Aryl chlorides and bromides can be easily prepared by electrophilic substitution of arenes with chlorine and bromine respectively in the presence of Lewis acid catalysts like iron or iron(III) chloride. 4.When a primary aromatic amine, dissolved or suspended in cold aqueous mineral acid, is treated with sodium nitrite, a diazonium salt is formed. 5.Mixing the solution of freshly prepared diazonium salt with cuprous chloride or cuprous bromide results in the replacement of the diazonium group by –Cl or –Br.
Pre-Requisites:
Elements, bond, alcohols
Activity:
1. Synthetic halogen compounds, viz. 2. Chloroquine is used for the treatment of malaria. 3. Halothane is used as an anesthetic during surgery.
Real Life Question:
What are haloarenes and haloalkanes ?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Haloalkanes | Haloalkanes contain halogen atom(s) attached to the sp3 hybridized carbon atom of an alkyl group. |
| Haloarenes | Haloarenes contain halogen atom(s) attached to sp2 hybridized carbon atom(s) of an aryl group. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| chloramphenicol | Chlorine containing antibiotic, chloramphenicol, produced by soil microorganisms is very effective for the treatment of typhoid fever. |
Real life uses :
1. Synthetic halogen compounds, viz. 2. Chloroquine is used for the treatment of malaria. 3. Halothane is used as an anesthetic during surgery.
Places to visit :
pharmacy
Practical examples around us
| Examples | Explainations |
|---|---|
| chloroquine | chloroquine is used for the treatment of malaria. |
| halothane | halothane is used as an anesthetic during surgery. |
What you learn in Theory:
1.Free radical chlorination or bromination of alkanes gives a complex mixture of isomeric mono- and poly haloalkanes, which is difficult to separate as pure compounds. 2.Consequently, the yield of any one compound is low 3.Aryl chlorides and bromides can be easily prepared by electrophilic substitution of arenes with chlorine and bromine respectively in the presence of Lewis acid catalysts like iron or iron(III) chloride. 4.When a primary aromatic amine, dissolved or suspended in cold aqueous mineral acid, is treated with sodium nitrite, a diazonium salt is formed. 5.Mixing the solution of freshly prepared diazonium salt with cuprous chloride or cuprous bromide results in the replacement of the diazonium group by –Cl or –Br.
What you learn in Practice:
Haloalkanes and Haloarenes are classified based on the number of halogen compounds contained in them