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IB Chemistry on Structural Isomers for Organic Molecules

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IB Chemistry on Structural Isomerism in Organic Chemistry
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Isomerism Isomers Organic molecules with same molecular formula but different arrangement of atoms Two types of Isomerism Structural Isomerism Same molecular formula Different structural formula Different arrangement of atoms Hydrocarbon Chain Isomer Different hydrocarbon chain skeleton Stereoisomerism Same molecular formula Same structural formula Different spatial arrangement of atoms Positional Chain Isomer Different functional group position Functional Group Isomer Different functional group Geometric Isomers Optical Isomers Cis Isomers Atoms are located on the same side Trans Isomers Atoms are located on the different side CH 3 -CH CH 2 CH 3 OH CH 3 -CH CH CH 3 OH CH 3 CH 2 CH 2 O CH 3 CH 3 -CH CH 2 CH 3 | OH CH 3 - CH CH 2 | CH 3 OH CH 3 -CH CH 2 CH 3 OH
Transcript
Page 1: IB Chemistry on Structural Isomers for Organic Molecules

Isomerism

Isomers – Organic molecules with same molecular formula but different arrangement of atoms

Two types of Isomerism

Structural Isomerism • Same molecular formula • Different structural formula • Different arrangement of atoms

Hydrocarbon Chain Isomer • Different hydrocarbon chain skeleton

Stereoisomerism • Same molecular formula • Same structural formula • Different spatial arrangement of atoms

Positional Chain Isomer • Different functional group position

Functional Group Isomer • Different functional group

Geometric Isomers

Optical Isomers

Cis Isomers Atoms are located on

the same side

Trans Isomers Atoms are located on

the different side

CH3 -CH –CH2 –CH3 │

OH

CH3 -CH –CH –CH3 │

OH

CH3 –CH2–CH2 – O – CH3

CH3 -CH –CH2 –CH3 | OH

CH3 - CH – CH2 │ |

CH3 OH

CH3 -CH –CH2 –CH3 │

OH

Page 2: IB Chemistry on Structural Isomers for Organic Molecules

Isomers – Organic molecules with same molecular formula but different arrangement of atoms

Structural Isomerism for C4H9OH • Same molecular formula

• Different structural formula • Different arrangement of atoms

Hydrocarbon Chain Isomer • Different hydrocarbon chain skeleton

Positional Chain Isomer

• Different functional group position

Functional Group Isomer • Different functional group

CH3 –CH2 –CH2 –CH3 │

OH

CH3 –CH2 –CH –CH3 │

OH

CH3 - CH – CH2 – OH │

CH3

CH3 │ CH3 - C – OH │

CH3

CH3 –CH2 –CH2 –CH3 │

OH

CH3 –CH2–CH2 – O – CH3

CH3 –CH2 – O – CH2 -CH3

Butan – 1-ol 2- Methylpropan-1-ol

2- Methylpropan-2-ol

Butan – 1-ol Butan – 2- ol

Butan – 1-ol Methoxypropane Ethoxyethane

Structural Isomerism

CH3 –CH2 –CH2 –CH3 │

OH

Page 3: IB Chemistry on Structural Isomers for Organic Molecules

H │ CH3 –CH2– C=O

O ║ CH3 – C– CH3

Structural Isomers for C4H9OH – All have same Molecular Formula but different Structural Formula

Isomers – Organic molecules with same molecular formula but different arrangement of atoms

Structural Isomerism

CH3 –CH2 –CH2 –CH2 │

OH

CH3 –CH2 –CH –CH3 │

OH

CH3 - CH – CH2 – OH │

CH3

CH3 │ CH3 - C – OH │

CH3

CH3 –CH2–CH2 –O – CH3

CH3 –CH2 –O– CH2 -CH3

C4H9OH C4H9OH C4H9OH

C4H9OH

C4H9OH C4H9OH

Structural Isomers for C4H9Br – All have same Molecular Formula but different Structural Formula

CH3 –CH2 –CH2 –CH2 │

Br

CH3 –CH2 –CH –CH3 │

Br

CH3 - CH – CH2 – Br

CH3

CH3 │ CH3 - C – Br

CH3

Structural Isomers for C3H6O – All have same Molecular Formula but different Structural Formula

OH │ CH3 –CH = C-H

OH │ CH2 =CH - C-H2

CH3 – O – CH = CH2

C4H9Br C4H9Br C4H9Br

C4H9Br

C3H6O C3H6O C3H6O C3H6O C3H6O

Page 4: IB Chemistry on Structural Isomers for Organic Molecules

Structural Isomerism

Isomers – Organic molecules with same molecular formula but different arrangement of atoms

Structural Isomers for C4H8

CH3 –CH = CH –CH3

CH2 = CH –CH2 –CH3

CH3 –CH2 –CH2 –CH2 │

OH

Structural Isomers for C4H10O

CH3 –CH2 –CH –CH3 │

OH

Hydrocarbon Chain Isomer • Different hydrocarbon chain skeleton

Positional Chain Isomer • Different functional group position

Functional Group Isomer • Different functional group

CH3-CH–CH2–OH │

CH3

CH3 │ CH3 - C – OH │ CH3

CH3-CH2-CH2-O–CH3

CH3 -CH2 –O–CH2-CH3

CH3–CH–O–CH3

|

CH3

CH3 –C=CH2

| CH3

CH2 – CH2

| | CH2 - CH2

Ether gp Alcohol gp Alcohol gp

Alkene gp Alkene gp Alkene gp Cycloalkane gp

Page 5: IB Chemistry on Structural Isomers for Organic Molecules

Structural Isomers for C4H8O

CH3 –CH2 –CH2 –C-H ║

O

CH3– CH – C-H | ║ CH3 O

CH3 –CH2 –C –CH3

║ O

CH2 =CH–CH2–CH2-OH

CH3 -CH = CH –CH2-OH

CH3 –CH2 -CH=CH-OH

CH3–CH2 -O- CH=CH2

CH3–CH =CH-O- CH3

Structural Isomers for C3H6O2

CH3–CH2 –C-OH ║ O

CH3 –C- O-CH3

║ O

H-C-O-CH2-CH3

║ O

CH2- CH = CH

| | OH OH

CH = CH–O–CH3

| OH

CH2 = C–O– CH3

| OH

CH2– CH-OH

CH -OH

Structural Isomerism

Aldehyde group

Ketone group

Alcohol + Alkene group

Ether + Alkene group

Carboxyl group

Ester group

Dialcohol + Alkene gp Ether , Alkene + Alcohol gp

CH2- C =CH2

| | OH OH

CH =C –CH3

| | OH OH

CH2 = CH–O–CH2

| OH

HO-C=CH–CH3

| OH

HO-CH-CH=CH2

| OH

CH3-O-CH2–C-H

║ O

OH | CH3-CH–C-H

║ O

OH | CH2-CH2–C-H

║ O

Aldehyde + Alcohol gp

Aldehyde + ether gp

Page 6: IB Chemistry on Structural Isomers for Organic Molecules

CH3 –CH2–CH2–CH2-CH2-CH3

Structural Isomerism

Structural Isomers for C6H14

CH3 –CH–CH2–CH2-CH3

| CH3

CH3 –CH2–CH–CH2-CH3

| CH3

CH3

| CH3 –C-CH2-CH3

| CH3

CH3 –CH–CH -CH3

| | CH3 CH3

Structural Isomers for C5H10

CH2 =CH–CH2-CH2-CH3

CH3-CH=CH-CH2-CH3

CH2 =C–CH2-CH3

| CH3

CH2=CH–CH-CH3

| CH3

CH3-CH=C-CH3

| CH3

CH3–CH- CH-CH3

CH2

CH2– CH- CH2-CH3

CH2

CH3

| CH2– C-CH3

CH2

CH2 – CH-CH3

| | CH2– CH2

C H2

CH2 CH2

| | CH2 –CH2

Alkene group Cycloalkane group

Page 7: IB Chemistry on Structural Isomers for Organic Molecules

Structural Isomerism

Structural Isomers for C5H11Br

CH3 –CH2–CH2–CH2-CH2 Br

CH3 –CH–CH2–CH2-Br

| CH3

CH3 –CH2–CH–CH2-Br

| CH3

CH3 -CH2–CH2–CH-CH3

| Br

CH3

| CH3–CH–CH-CH3

| Br

CH3

| CH3–CH2–C-CH3

| Br

CH3 -CH2–CH–CH2-CH3

| Br

CH3

| CH3 –CH2- C-Br

| CH3

CH3 CH3

| | CH3– C- CH2

| Br

Are these different isomers too?

No

CH3–CH–CH-Br

| | CH3 CH3

CH3

| CH3 –C-CH2-Br

| CH3

same

Page 8: IB Chemistry on Structural Isomers for Organic Molecules

Structural Isomerism

Structural Isomers for C4H8O2

CH3-CH2-CH2 –C-OH ║ O

CH3-CH – C-OH | ║ CH3 O

CH3 –C- O-CH2-CH3

║ O

H–C- O-CH2-CH2-CH3

║ O

CH3–CH2–C- O-CH3

║ O

CH2- CH2-CH = CH

| | OH OH

CH2- CH=CH- CH2

| | OH OH

CH2- CH-CH =CH2

| | OH OH

CH2- C =CH- CH3

| | OH OH

CH = C - CH2- CH3

| | OH OH

CH3- C = C - CH3

| | OH OH

CH2 = C - CH- CH3

| | OH OH

CH3

| CH = C –CH2

| | OH OH

CH2

║ CH2 - C -CH2

| | OH OH

OH | CH3-CH2-CH–C-H

║ O

OH | CH3-CH-CH2–C-H

║ O

OH | CH2-CH2-CH2–C-H

║ O

OH | CH3-C – C-H

| ║ CH3 O

OH | CH2-CH – C-H

| ║ CH3 O

CH3-O-CH2- CH2–C-H

║ O

CH3CH2-O- CH2–C-H

║ O

CH3

| CH3-O- CH–C-H

║ O

CH = CH-CH2 –O–CH3

| OH

CH = CH –O–CH2-CH3

| OH

CH2 = C-CH2 –O–CH3

| OH

CH2 –CH=CH –O–CH3

| OH

CH3–CH=CH–O–CH2

| OH

CH2 - CH-OH

| | CH2 – CH-OH

CH2 - CH-OH

| | HO-CH – CH2

Carboxyl gp

Ester gp

Cyclic dialcohol gp

Alkene + dialcohol gp

Alkene + Ether + Alcohol gp Aldehyde + ether gp Aldehyde + Alcohol gp

Any more isomers that you can draw?


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