ib chemistry on organic chemistry, iupac nomenclature and structural formula

Homologous Series • same functional group

• each member differ from the next by –CH2 - group • similar chemical properties • same chemical formula CnH2n+2

• saturated hydrocarbon • ending with ane

Physical properties • increase in RMM and molecular size down the series •RMM increase ↑ - Van Der Waals forces stronger melting /boiling point increases ↑ • C1 – C4 (gas) • C5- C18 (liquid) • C19 – (solid) • Insoluble in water, soluble in organic solvent • Non conductors – simple molecules NOT ions

Hydrocarbon Alkane and Nomenclature

Aliphatic (open chain) Aromatic (benzene structure)

Saturated

Carbon – Carbon single bond Unsaturated

Carbon – Carbon double bond

Alkane Cycloalkane

melting /boiling point increases ↑ as carbon chain increases ↑

Hydrocarbon

CH3CH3 CH3

CH3 CH3

CH3 CH3 CH2 CH2

Condensed Structural Formula Vs Displayed structural formula

• branches in carbon chain are indicated in parentheses all carbon and hydrogen bonds are shown

• CH3CH(CH3)CH3

• CH3CH(OH)CH2CH(OH)CH3

Molecular Formula Actual number of atoms/elements present in a molecule

Ex : C2H5CI1 – 2 Carbon, 5 Hydrogen, 1 Chlorine

Structural Formula Arrangement of all atoms in a molecule

Ex : H H H

│ │ │ H - C – C – C - H │ │ │

H CH3 H

H H H H H

│ │ │ │ │ H - C – C – C – C – C - H │ │ │ │ │ H OH H OH H

H H H

│ │ │ H - C – C – C - H │ │ │

H CH3 H

Hydrocarbon Alkane and Nomenclature

Nomenclature for Organic Molecules

Name the parent (longest unbranched carbon chain)

Choose the chain which has more alkyl groups attached

Name alkyl/substituent/attached groups by adding a suffix with yl CH3 – methyl

C2H5 – ethyl

C3H7 – propyl

C4H9 – butyl

7 carbon - heptane

or

or

7 carbon - heptane

Branching groups are

• methyl and ethyl

Step 2

Step 3

3 alkyl groups 4 alkyl groups

Step 1

Numbering from end of chain which give substituents the lowest possible numbers

If 2 or more identical substituents present, assign prefixes

2 identical (Di) – 3 identical (Tri) – 4 identical (Tetra) – 5 identical (Penta)

2, 4, 5 –trimethylheptane NOT 2, 4, 5 –trimethyl - heptane Use comma, to separate numbers

Use hyphen – to separate number and word

Write prefix and parent as one word

3 – ethyl – 2, 4, 5- trimethylheptane NOT 2, 4, 5 - trimethyl – 3 – ethylheptane

Arrange the substituents according to alphabetical order

√ or

Numbering are 2 , 3, 4, 5 Numbering are 3, 4, 5, 6

Nomenclature for Organic Molecules

Step 4

Step 5

Step 6

Step 7

√ X

√

3 – ethyl – 2, 4, 5 - trimethylheptane

3 identical - Trimethyl

2- methyl- 4- ethylhexane 3- ethyl- 5- methylhexane

Nomenclature for Organic Molecules

2, 3 - dimethylpentane 4-ethyl-2 -methylhexane

2, 3, 6 – trimethyl – 4 - ethyloctane 2, 2, 4 - trimethylpentane

X √

Aliphatic (open chain) Aromatic (benzene structure)

Saturated Unsaturated

Hydrocarbon

CH3 CH3

Homologous Series • same functional group (C=C) or (C≡C) • each member differ from the next by –CH2- group • similar chemical properties • chemical formula alkene - CnH2n

• chemical formula alkyne - CnH2n-2

•unsaturated hydrocarbon • alkene ending with ene • alkyne ending with yne

Physical properties – • increase in RMM and molecular size down the series •RMM increase ↑ - Van Der Waals forces stronger melting /boiling point increases ↑ • C2 – C4 (gases) • C5- C10 (liquids) • Insoluble in water, soluble in organic solvent • Non conductors – simple molecules not ions

Hydrocarbon Alkene/Alkyne and Nomenclature

Unsaturated

Carbon – Carbon double bond

Unsaturated

Carbon – Carbon triple bond

CH CHH2C=CH2

Homologous Series • functional group CO bonded to H at the end • contain carbonyl group C=O • each member differ from the next by –CH2- group • similar chemical properties • chemical formula aldehyde - CnH2nO • aldehyde ending with al

Hydrocarbon Aldehyde and Nomenclature

H H H │ │ │ H- C - C – C =O │ │

H H

Propanal

H H H H

│ │ │ │ H- C - C – C – C =O │ │ │

H H H

Butanal

H H │ │ H- C – C = O │

H

Ethanal

H │ H- C =O

Methanal

Physical properties –

• increase in RMM and molecular size down the series

•RMM increase ↑ - Van Der Waals forces stronger

melting /boiling point increases ↑

• C1 – gas

• C2- C10 - liquids

• Methanal – CH2O

• Ethanal - CH3CHO

• Propanal – CH3CH2CHO

• Butanal - CH3CH2CH2CHO

H │ CH3 – CH –CH – C=O │ CH3

H │ CH3 – CH –CH – C=O │ │ CH3 CH3

CH3 H │ │ CH3 –CH – C=O │ CH3

2 - methylbutanal 2, 3 - dimethylbutanal 2, 2-dimethylpropanal

Nomenclature for aldehyde

Homologous Series •functional group CO bonded to two hydrocarbon • contain carbonyl group C=O • each member differ from the next by –CH2- group • similar chemical properties • chemical formula ketone - CnH2nO • ketone ending with one

Hydrocarbon Ketone and Nomenclature

H H │ │ H- C - C – C - H │ ║ │

H O H

Propanone

H H H

│ │ │ H- C - C – C – C -H │ │ ║ │

H H O H

Butan- 2 - one

Physical properties –

• increase in RMM and molecular size down the series

•RMM increase ↑ - Van Der Waals forces stronger

melting /boiling point increases ↑

• C1 – gas

• C2- C10 - liquids

• Propanone – CH3COCH3

• Butanone - CH3CH2COCH3

• Pentan-3-one -CH3CH2COCH2CH3

• Hexan-3-one - CH3CH2COCH2CH2CH3

H H H H H

│ │ │ │ │ H- C - C – C – C – C – C – H │ │ ║ │ │ │

H H O H H H

Hexan-3 - one

H H H H │ │ │ │ H- C - C – C – C – C - H │ │ ║ │ │

H H O H H

Pentan- 3-one

CH3 – C –CH – CH3

║ │ O CH3

CH3 │ CH3 – C –C – CH3

║ │ O CH3

CH3 │ CH3 – CH – C – CH- CH3

║ │ O CH3

3, 3 dimethylbutanone 3- methylbutanone 2, 4 dimethylpentan- 3-one

CH3 – C –CH – CH2CH3

║ │ O CH3

3- methylpentan-2-one

Nomenclature for ketone

Homologous Series •functional group COOH • contain carbonyl group C=O • each member differ from the next by –CH2- group • similar chemical properties • chemical formula carboxylic acid - CnH2n+1COOH or CnH2nO2

• acid ending with oic

Hydrocarbon Carboxylic Acid and Nomenclature

H H O

│ │ ║ H- C - C – C - OH │ │

H H

Propanoic acid

H H H O

│ │ │ ║ H- C - C – C – C -OH │ │ │

H H H

Butanoic acid

Physical properties –

• increase in RMM and molecular size down the series

•RMM increase ↑ - Van Der Waals forces stronger

melting /boiling point increases ↑

• Propanoic acid – CH3CH2COOH

• Butanoic acid - CH3CH2CH2COOH

• Pentanoic acid - CH3CH2CH2CH2COOH

• Hexanoic acid - CH3CH2CH2CH2CH2COOH

H H H H H O │ │ │ │ │ ║ H- C - C – C – C – C – C - OH │ │ │ │ │

H H H H H

Hexanoic acid

H H H H O │ │ │ │ ║ H- C - C – C – C – C - OH │ │ │ │

H H H H

Pentanoic acid

O ║ CH3 – CH –CH – C -OH │ │ CH3 CH3

CH3 O │ ║ CH3 – CH –CH – C -OH │ CH3

O ║ CH3 –CH – C -OH │ CH3

2, 3 -dimethylbutanoic acid 3, 3–dimethylbutanoic acid 2- methylpropanoic acid

Nomenclature for carboxylic acid

H │ CH3 - C – OH │ H

Homologous Series

• same functional group hydroxyl (OH)

• each member differ from the next by –CH2 - group

•same chemical formula alcohol - CnH2n+1OH

•ending with ol

• Methanol – CH3OH

• Ethanol - CH3CH2OH

• Propanol – CH3CH2CH2OH

• Butanol – CH3CH2CH2CH2OH

Hydrocarbon Alcohol and Nomenclature

Types of alcohol Primary alcohol 1 0 – One alkyl group bonded to C attached to OH group

Secondary alcohol 2 o – Two alkyl group bonded to C attached to OH group

Tertiary alcohol 3 o – Three alkyl group bonded to C attached to OH group

CH3 │ CH3 - C – OH │

H

CH3 │ CH3 - C – OH │ CH3

H H H │ │ │ H- C - C – C - H │ │ │

H H OH

Propan – 1-ol

H H H │ │ │ H- C - C – C - H │ │ │

H OH H

Propan – 2-ol

H H H H

│ │ │ │ H- C - C – C – C - H │ │ │ │

H H H OH

Butan–1-ol

H H H H

│ │ │ │ H- C - C – C – C - H │ │ │ │

H H OH H

Butan–2-ol

H H H │ │ │ H- C - C – C – OH │ │ │

H CH3 H

2- Methylpropan-1-ol

H OH H │ │ │ H- C - C – C – H │ │ │

H CH3 H

2- Methylpropan-2-ol

Nomenclature for Organic Molecules

C6– C5 – C4 – C3- C2 – C1

│

C2H5

C4 – C3 - C2 = C1

│

CH3

C4 – C3 - C2 - C1HO

│

CI

C3 - C2 - C1 - OH

│

CH3

C3 - C2 - C1OOH

│

Br

OH │

C3 - C2 - C1

│

CH3

C5 - C4 – C3 - C2 = C1

│

CH3

C5 - C4 – C3 - C2 - C1

│ ║

CH3 O

3 ethylhexane

2- methylbutene

2 – chlorobutanal

2 –methylpropan- 1-ol 3 – bromopropanoic acid

2 – methylpropan – 2-ol

3 – methylpent –1-ene 3 methylpentan-2-one

CH3 – C = CH2

│ CH3

2 - methylpropene

CH3 – CH2 – CH - CI

│ CH2CH3

3 - chloropentane

CH3 – CH –CHO │ CH3

2 -methylpropanal

CH3 – CH –CH – CH3

│ │ CH3 OH

3- methylbutan-2-ol

CH3 – CH –CH2 – CH2OH

│ CH3

3- methylbutan- 1-ol

CH3 – CH –CH2 - OH │ CH3

2- methylpropan-1-ol

CH3 – CH –CH2 – CH3

│ CH2OH

2- methylbutan-1-ol

Nomenclature for Organic Molecules

HO-C(CH3)2 – CH2-CH2-COOH

4- hydroxy- 4 –methylpentanoic acid

CH3-CH(OH)-CH3

propan- 2–ol

CH2 -C(CH3)2

2- methylpropene

CH3-C(CH3)2-CH2-CHO

3, 3 – dimethylbutanal

CH3-CH(CH3)-CO-CH2-CH3

2 –methylpentan –3-one

(CH3 )3C –Br

2- bromo- 2-methylpropane

CH3-CH2-CHBr-COOH

2- bromobutanoic acid

CH3 – CHBr – CH2 –CH2 -OH

3- bromo-butan-1-ol

Nomenclature for Alkene and Alcohol Molecules

6 –chloro–3-ethylhev-1-ene

2 –methylbut-2-ene 3 –methylpent-1-ene

6 –chloro-2–methylhex-2-ene

2, 3 –dimethylbut-2-ene

3 –methylbut-1-ene

4- methylpentan-1-ol 3, 3–dimethylpentan-2-ol 2- methylbutan-2-ol

2 – methylpropan-2 -ol Pent –4-ene –2-ol