Organic Chemistry
Organic Chemistry
• Organic means living
• Hydrocarbons contain hydrogen and carbon atoms
• Organic Chemistry is the study of carbon chemicals
that are natural and artificial.
• The bonding in hydrocarbons is covalent so bonding
between molecules is weak.
Organic compounds
The structural formula of a compound
shows the bonds between carbon
atoms, but not the atoms themselves.
Hydrogen atoms are also omitted, but
other atoms are shown.
Alkanes
General formula- a formula for a homologous series of
compounds.
E.g. alkanes CnH2n+2 where n is the number of carbon
atoms
Methane: CH4
CnH2n+2
n=1
C1H(2x1)+2
Propane: C3H8
C3H(2x3)+2
n=3
Naming alkanes
Alkanes
Methane
CH4
Ethane
C2H6
Propane
C3H8
These hydrocarbons are said to be saturated.
(They have single bonds between carbon atoms).
Basic names of Alkanes
1) name will end in -ane,
2) the number of carbons is given by a “Prefix”
1 meth- 2 eth-
7 hept- 8 oct-
3 prop- 4 but- 5 pent- 6 hex-
9 non- 10 dec-
Naming alkanes: branched
The longest unbranched chain containing the functional group is the
parent molecule
De name of the branch ends with –yl.
Common side chains include:
CH3- methyl
CH3CH2- ethyl
CH3CH2CH2- propyl
Indicate the position of the branch
with a number, numbering from
the end that gives you the lowest
number
CH3 CH3
| | | | | |
— C—C—C—C—C— C —
| | | | | |
2e 4e
2,4 - dimethyl Hexane
Naming branches Alkanes
Parent molecule: The longest unbranched chain
Branch: methyl (1 C) or ethyl ( 2 C) etc.
Numbering: Indicate the position of the branch with a
number
CH3
|
CH2 – CH2 – CH
|
|
CH3
CH3
Parent: pentaan
Branch: methyl (CH3)
Number: 2 (not 4)
Name: 2-methylpentane
Parent molecule: 5 C-atoms = pentane
side-branch: 1 C-atom = methyl
 methylpentane
CH3
CH
CH2
CH2
CH3
Position number:
From left to right = number 2
CH3
From right to left = number 4
Lowest number is number 2
 2-methylpentane
Parent molecule: 5 C-atoms = pentane
Side branch: 2 x 1 C-atom = dimethyl
 dimethylpentane
CH3 CH
CH
CH3 CH3
CH2
CH3
Position number:
Number from left to right= 2 + 3 = 5
Number from right to left = 3 + 4 = 7
Smallest sum = 2 + 3 = 5
 2,3-dimethylpentane
5 C-atoms = pentane
CH3
CH
CH
CH3
CH2
CH2
Side branch: 1 C-atoom = methyl
Zijketen: 2 C-atomen = ethyl
 ethylmethylpentane
CH3
Position number
Numbering from left to right = 2 + 3 = 5
Numbering from right to left = 4 + 3 = 7
Smallest sum = 2+3
 3-ethyl-2-methylpentane
CH3
3-ethyl-2,3-dimethylpentane
1. C
C
C
C
C
2. C  C  C  C  C
3.
4.
C

C

C  C  C  C  C


C C
CH3

CH2

CH3  CH  C  CH2  CH3


CH3 CH3
Systematische naamgeving zijgroepen
Structural formula
CH3 CH2 CH
IUPAC name
CH2 CH3
3-ethylpentane
CH2 CH3
3-ethyl-2-methylpentane
CH2
CH3
CH3 CH
CH
CH3 CH2
CH3
Voorbeeld
Structural formula
IUPAC name
CH3
H2C
CH
2-methylbutane
CH3
CH3
CH3
sum = 13 4
4,5
2,3
sum = 8 33-ethyl-2,3-dimethylhexane
CH2
CH2 CH3
H3C
4
CH2 C
5
CH
3
2
CH3
CH3
H3C
CH2 CH3 CH2 CH3
H3C
3
4
5
CH C
C
6
5
4
CH3
CH2 CH2 CH2 CH3
CH3
sum = 21
sum = 24
4,5
3,4,5
4,5-diethyl-3,4,5-trimethyloctane
4,5
4,5,6
Systematische naamgeving zijgroepen
n
6
Structural formula
Molecular formula
IUPUC name
CH3 CH2 CH2 CH2 CH2 CH3
C6H14
hexane
CH3 CH2 CH2 CH
CH3
C6H14
2-methylpentane
CH2 CH3
C6H14
3-methylpentane
CH3
C6H14
2,3-dimethylbutane
C6H14
2,2-dimethylbutane
CH3
CH3 CH2 CH
CH3
CH3 CH
CH
CH3 CH3
CH3
CH3 C
CH3
CH2 CH3
Isomerism p176
• Isomers are substances which have the same
molecular formula but different structural
formula.
Onvertakt en vertakt
n
Structural formula
4
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
H
H
C
C
C
H
H
C
H
Molecular formula
IUPAC name
C4H10
butane
C4H10
methylpropane
H
o
r
o
r
H
H
o
r
H
o
r
isomers =
same molecular formula
different structural formule
Systematische naamgeving zijgroepen
n
structuurformule
5
H
H
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
Molecular formula
H
IUPAC name
C5H12
C5H12
pentane
2
methylbutane
H
H
H
H
H
C
H
H
C
C
C
H
H
C5H12
H
C
H
H
H
2,2
dimethylpropane
Systematische naamgeving zijgroepen
n
Structural formula
H
6
H
H
H
H
H
H
CH
CH3 H
C 3 CH
C 2 CH
C 2 CH
C 2 CH
C 2 C
H
H
H
H
H
H
Molecular formula
C6H14
IUPAC name
hexane
Systematische naamgeving zijgroepen
n
Structural formula
Molecular formula
CH3 CH2 CH2 CH2 CH2 CH3
6
H
H
H
H
H
CH3 C
C
CH2 C
CH2 CH
C
H
H
H
H
CH3 CH2 CH
CH3
CH
C 3
C6H14
hexane
CH
2-methylpentane
H
H
H
H
H
H
CH
C 3 H H
C
C
C
C
C 6 H14
H
H
C
H
H
H
H
H
H
H
CH2 CH3
H
IUPAC nama
C6H14
3-methylpentane
Properties of Alkanes
Verbranding
Combustion is a reaction with oxygen .
Complete combustion: enough oxygen is present
hydrocarbon
ex:
+ oxygen
C3H8 +
5 O2 
carbondioxide + water
3 CO2 + 4 H2O
Incomplete combustion: incomplete combustion
hydrocarbon
+ oxygen 
carbonmonoxide + water
CO is
poison
Cracking is a procces where longer C-chain break into smaller useful C-chains.
Kraken
For example, more petrol can be made in this way than can be
obtained from crude oil using only a distillation tower.
C10H22  C5H12 + C5H10
ex:
CnH2n+
CnH2n+
2
2
CnH2n
C10H22  C6H14 + C4H8
C10H22  C4H10 + C6H12
ex 2:
CH3 CH2 CH2 CH2 CH2 CH3
alkane
 CH3 CH3
+ alkane
H2C
CH
CH2 CH3
alkene
Alkenes
• The unsaturated hydrocarbons form an homologous
series called alkenes with a general formula CnH2n
• Unsaturated means the molecule has a C=C double
bond to which atoms or groups can add.
• Alkene examples: Names end in ...ene
Production of Alkenes
• longer alkanes are turned into smaller ones by
a process called cracking.
• Cracking produces short alkenes and shorter
alkanes.
• Exp. Ethene is used in making plastics
(polymerisation)
Systematische naamgeving alkanen
n
2
Structural formula
H
H
C
C
H
3
4
H
H
H
H
C
C
C
H
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
H
Molecular formula IUPAC name
C2H4
ethene
C
C
C
C
H
H
H
H
o
r
H
H
C3H6
propene
C4H8
butene
but-1-ene
C4H8
butene
but-2-ene
o
r
o
r
CnH2n
Naming side chains
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
Rule 1: choose the correct ending
ene
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
Rule 2: parent chain = longest carbon chain
that contains double bond
ene
The longest unbranched chain containing the functional
group is the parent molecule
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
Rule 3: Always give double bond the lowest
number
1-hexene
ene
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
Rule 4: Assign numbers to each carbon
1-hexene
Naming side chains
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
Rule 5: Determine name for side chains
1-hexene
Naming side chains
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
Rule 6: attach name of branches
2-ethyl-4,4-dimethyl-1-hexene
Naming side chains
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
Rule 7: list alphabetically
2-ethyl-4,4-dimethyl-1-hexene
6
CH3
methyl
methyl
Naming side chains
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
Rule 8,9: group similar branches
2-ethyl-4,4-dimethyl-1-hexene
Voorbeeld
Structural formula
CH3
1
H2C
CH
3
CH
IUPAC name
3-methylpent-1-ene
CH2
CH3
H3C
H2C
CH3
4C
CH3
3
2
CH C
H3C
CH2 CH3
H3C
CH2
H3C
6
5
4
CH CH CH
H3C
3-ethyl-4,4-dimethylhex-2-ene
CH2 CH3
CH2 CH
2
CH
4,5-diethyl-6-methyloct-2-ene
CH3
H
H
CH3 H
H
C
C
C
C
H
H
H
H
H
methylbutane
H
H
C
H
H
C
H
C
H
CH3 H
C
C
H
H
C
C
H
H
F
H
H
H
C
C H
H
H
2-buteen
H
3-methyl-1-butene
H
C
H
H
C
C
H
H
methylpropeen
Addition reaction
Addition reaction: adding a smaller molecule to a bigger molecule.
A smaller molecule (like dibromide, Br2) is added and reacts with the weaker C=C
of an alkene.
ex:
H
Br
Br
H
C
C
C
H
H
H
propene

H
H
Br
Br
H
C
C
C
H
H
H
H
1,2-dibroompropane