Embed Size (px)
Citation preview
11
Structural IsomerismStructural Isomerism
Exclusively Developed by K. Chandana
For my sincere online students.
For further enquiry write to [email protected]
22IsomersIsomers Structural Isomers:Structural Isomers: Isomers ,which have
same molecular formula, but different structural formula are called structural isomers.
Different Structural formula means Different bond pattern or Different arrangement of bonds or Different connectivity of atoms.
The key to organic chemistry is crystal clear understanding of different terms used.
33IsomersIsomers Example 1-chloropropane and 2-chloropropane has
different structural formula.
44IsomersIsomers Example cis-2-butene and trans-2-butene has same
structural formula.
55IsomersIsomers Type of Structural Isomers.
1. Chain Isomerism
2. Positional Isomerism
3. Functional Isomerism
4. Metamerism.
5. Tautomerism
66IsomersIsomers Chain Isomerism: Isomers which have
same functional groups but different arrangement of carbon skeleton in principal chain or side chains are chain isomers.
Note 1. No of atoms same
2.No. of D.U same.
3. Functional groups Same.
4. Carbon skeleton different
77IsomersIsomers
Example1.Ethylbenzene and o-Xylene.
2. Butanoicacid and 2-methylpropanoicacid,
88IsomersIsomers Positional Isomerism: Isomers which have
same functional groups ,same arrangement of carbon skeleton but different position of functional groups or substituents.
Note 1. No of atoms same
2.No. of D.U same.
3. Functional groups Same.
4. Carbon skeleton Same
5.Position of F.G, differs
99IsomersIsomers
Example 1. 1-butanol & 2-butanol
2. O-Xylene & m-Xylene.
1010IsomersIsomers Functional Isomers: Isomers which have
different functional group.
Note 1. No of atoms same
2. No. of D.U same.
3. Functional groups differs
1111IsomersIsomers
Example 1. 1-butanol & Ethoxyethane
2. Ethanal and Oxirane.
1212IsomersIsomers Metamers: Isomers which have different
carbonchain lenth along a functional group withhetro atom (Ex- Ethers, Esters, secondary amines, tertiary amines , Secondary amides etc.
Note 1. No of atoms same
2. No. of D.U same.
3. Functional groups same.
4. Number of carbon differs along hetro atoms.
1313IsomersIsomers
Example 1. Methoxypropane & Ethoxyethane
2. Ethylethanoate and Methylpropanoate.
1414IsomersIsomers Tautomers: A type of functional Isomers
which exist in rapid equilibrium in solution are called functional isomers.
Tautomers are interconvertable in solution Tautomers usually differs in position of H
atom at carbon. Interconversion of tautomers can be
catalysed. Tautomers can’t be seperated in solution at
normal temperature. The more stable form dominates in
equillibrium.
1515IsomersIsomers Only the stable tautomeric form is counted
while counting isomers. Type-1 Keto- Enol tautomerism. Example Cyclohexanone and cyclohexenol
1616IsomersIsomers Type-2 Nitro-Acinitro Example nitrocyclohexane and
acinitrocyclohexene
1717IsomersIsomers Type-3 Imine - En-amine Example cyclohex-1-en-1-amine
and cyclohexanimine
1818IsomersIsomers Type-4 Cyano - isocyano Example Cyanicacid and isocyanicacid.
1919IsomersIsomers Type-4 Cyano - isocyano Example Cyanicacid and isocyanicacid.
2020IsomersIsomers There are several types of tautomerism, There are several types of tautomerism,
which will be discussed in details in which will be discussed in details in carbanion section of reaction mechanism.carbanion section of reaction mechanism.
2121Exercise-1Exercise-1 Identify the relationship between given pair
of compounds.
2222Exercise-1Exercise-1 Answer:- Functional isomers.
2323Exercise-2Exercise-2 Identify the relationship between given pair of
compounds.
2424Exercise-2Exercise-2 Answer- Chain isomerism.
2525Exercise-3Exercise-3 Identify the relationship between given pair
of compounds.
2626Exercise-3Exercise-3 Answer :- Different compounds Number of carbon as well as functional
group differs.
2727Exercise-4Exercise-4 Identify the relationship between given pair
of compounds.
2828Exercise-4Exercise-4 Answer :- Metamers. Number of carbon along hetro atom differs.
2929Exercise-5Exercise-5 Identify the relationship between given pair of
compounds.
3030Exercise-5Exercise-5 Answer :- Functional isomers A has Aldehydes group but B has ketone.
3131Exercise-6Exercise-6 Identify the relationship between given pair of
compounds.
3232Exercise-6Exercise-6 Answer :- Positional isomers
3333Exercise-7Exercise-7 Identify the relationship between given pair of
compounds.
A .Hexane-2-ol B. Heptane-2-ol
3434Exercise-7Exercise-7 Answer :- Homologous compounds.
Compounds with different carbon but with same functional groups are called homologous compounds.
3535Exercise-8Exercise-8 Identify the relationship between given pair
of compounds.
A. Methylcyclopropane B. Cyclobutane
3636Exercise-8Exercise-8 Answer :- Chain isomers
3737Exercise-9Exercise-9 Identify the relationship between given pair
of compounds.
A. 1-Butene B. cyclobutane
3838Exercise-9Exercise-9 Answer :- Functional isomers (Some
literature also mention ring chain isomerism.)
3939Exercise-10Exercise-10 Identify the relationship between given pair of
compounds.
4040Exercise-10Exercise-10 Answer :- Metamers.
4242Concept Developed by Concept Developed by Previous Presentation
DU and isomerism Next Presentation.
How to find no of structural isomers
