ib chemistry on organic chemistry, iupac nomenclature and structural formula
DESCRIPTION
IB Chemistry on Organic Chemistry, IUPAC Nomenclature and structural formulaTRANSCRIPT
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