Summary Module 4 Core organic chemistry and analysis

MODULE 4
CORE ORGANIC CHEMISTRY

CH 11 BASIC CONCEPTS OF ORGANIC CHEMISTRY
11.1 ORGANIC CHEMISTRY
WHAT IS ORGANIC CHEMISTRY?
 Modern organic chemistry studies the structure, properties, composition, reactions,
and preparation of carbon-containing compounds.
 Organic compounds are vital in every area of modern life: pharmaceuticals,
detergents, dyes and pigments, plastics…
 They all contain the element carbon.
 Today, the vast majority of the organic materials used are produces from fractions of
crude oil as fuels in domestic central heating systems.

WHY IS CARBON SPECIAL?
Carbon is in group 4 of the periodic table, with four electrons in its outer shell.
Therefore it can form four covalent bonds.

HYDROCARBONS
 Contain carbon and hydrogen only.
 SATURATED hydrocarbons contain only single bonds.
 UNSATURATED hydrocarbons contain carbon – carbon double bonds.

HOMOLOGOUS SERIES
 A homologous series is a family of compounds with similar chemical properties in
which successive members ass a – CH2 group.
 The simplest homologous series is the alkanes.

METHANE, CH4
ETHANE, C2H6
PROPANE, C3H8
BUTANE, C4H10

FUNCTIONAL GROUP
A functional group is the part of an organic molecule that is largely responsible for the
molecules’’ chemical properties.

NAMING COMPOUNDS CONTAINING FUNCTIONAL GROUPS
The same basic principles apply as for naming alkanes.
1. Identify the longest unbranched chain of carbon atoms. The stem is now the name of
the corresponding alkane.
2. Identify any functional groups and any alkyl side chains and select the appropriate
prefixes or suffixes for them.
3. Number any alkyl groups and functional groups to indicate their position on the
longest unbranched chain.
NAMING ALCOHOLS
1. Identify the functional group and suffix.

, 2. Identify the longest chain of carbon atoms.
3. Identify which carbon atom the functional group is on.
4. Combine the suffix, and stem to name the compound.

NAMING ALDEHYDES
1. Identify the functional group and suffix.
2. Identify the longest chain of carbon atoms.
3. Combine the suffix and stem to name the compound. aldehydes do not need
numbers to show the position of the carbonyl group. It is always on position 1.

NAMING MULTIPLE FUNCTIONAL GROUPS
1. Identify the longest chain of carbons.
2. Identify the functional groups present, which carbon atom they are on, and the
prefixes.
3. Combine the stem and the prefixes to name the compound. Remember side chains
are named in alphabetical order.

11.2 - NOMENCLATURE OF ORGANIC COMPOUNDS
NOMENCLATURE OF HYDROCARBONS
‘nomenclature’ = naming
 IUPAC rules are used to name hydrocarbons to allow chemists worldwide to
communicate effectively.

HYDROCARBONS ARE CLASSIFIED AS…
ALIPHATIC – carbon atoms are joined together in branched or unbranched (straight) chains.
ALICYCLIC – carbon atoms are joined together in cyclic (ring) structures.
AROMATIC – some or all of the carbon atoms are found in a benzene ring.

There are three homologous series of aliphatic hydrocarbons:
ALKANES – containing single carbon-carbon bonds.
ALKENES – containing at least one carbon – carbon double bonds.
ALKYNES – containing at least one carbon-carbon triple bond.

STEM, PREFIX AND SUFFIX
 The stem of the name indicates the number of carbon atoms in the longest
continuous chain.
 The prefix is used to indicate the presence of side chains or functional groups.
 A suffix is added to indicate functional groups.

METHYL – CH3  Alkane – butane
ETHYL – C2H5  4 carbon atoms
PROPYL – C3H7  2, 2 (CH3 lies on carbon 2 and there are 2 CH3)

Number of Alkyl’s:
Di – two
Tri –three DIMETHYLBUTANE
Alkane - butane
Tetra- three
Alkyl lies on carbon 2 (smallest)
2 METHYLBUTANE

,  Alkyl – methyl (CH3)

NOMENCLATURE OF ALICYCLIC ALKANES
Prefix – cyclo
Cyclo-hydrocarbon name CYCLOPENTANE

NOMENCLATURE OF ALKENES
Alkene – ene
 Show where double bond sits
 Hydrocarbon – number of where double bond starts – ene




1-CHLORO-METHYLCYCLOHEXANE


11.3 – REPRESENTING THE FORMULAE OF ORGANIC COMPOUNDS
MOLECULAR FORMULA – shows the number of each type of atom present in one molecule
of the compound.

EMPIRICAL FORMULA – shows the simplest whole number ratio of the atoms present.
C2H6 – CH3 (METHYL)
C6H12O6 – CH2O – CH2O
C2H4O2 – CH2O

GENERAL FORMULA – is the simplest algebraic form for any number of a homologous series.
It can be used to generate the molecular formula for any member of that homologous
series.

CnH2nO2 – CARBOXYLIC ACID
Name of C6H12O2?
 6 carbons
Hexanoic acid
DISPLAYED FORMULA – shows the arrangement of atoms in a molecule, as well as all the
bonds.



ETHANOL (C2H6O)

METHOXYMETHANE (C2H6O)
H2C=CH2
STRUCTURAL FORMULA – shows how the atoms are arranged in a molecule and shows
which functional groups are present.
 Structural formula don’t show single bonds, although double/triple
bonds may be shown.