Organic Chemistry
WHAT IS ORGANIC CHEMISTRY
The scientific study of carbon based compounds, hydrocarbons, and their
derivatives.
ORGANIC CHEMISTRY CON’T
Including the study of structure, properties, composition, reactions and preparation of these carbon based compounds
these carbon based compounds can include other elements such as: Hydrogen, Nitrogen, oxygen
GENERAL THEMES IN ORGANIC CHEMISTRY
Organic chemistry=Ochem “ R”groups represent attached groups of
atoms, such as Hydrocarbon side chains.
Hydrocarbon: compounds containing only Carbon and Hydrogen.
Remember Carbon always have “4 bonding e-”
HOMOLOGOUS SERIES Organic compounds
are members of homologous series similar to a family
To be part of a homologous series the members differ by a –CH2 group
For example Alkanes:
HOMOLOGOUS SERIES CON’T Homologous series:
Show similar chemical reactivity.
Can be represented by same general formula
Show similar chemical properties
Show gradual changes in physical properties.
TYPES OF HYDROCARBONS Hydrocarbons are classified into
two main groups Aliphatics (alkanes, alkenes,
alkynes) which contain branches but do not contain a benzene ring.
Aromatic hydrocarbons are a unique type of cyclic hydrocarbon that is derived from a benzene ring
Hydrocarbons have two types of carbon-carbon (C-C) bonding
Single bonds only=Saturated Hydrocarbons contain only C-C single bonds throughout. Every available electron sharing site is
occupied (saturated) by hydrogen atoms
Double/triple bonds= Unsaturated hydrocarbons
contain at least one C-C double bond or triple bond.
This means that some electron sharing sites on the carbon atoms are occupied by other carbon atoms (not saturated with hydrogen atoms).
Formulas for organic compounds
There are 3 types: 1. Empirical- simplest whole number ratio
of the atoms it contains ethane: C2H6CH3 Ethanoic AcidCH3COOHC2H4O2CH2O Glucose C6H12O6CH2O doesn’t give a whole lot of detail so it is not
often used.
Formulas for organic compounds
2. Molecular Formulas The actual number of atoms of each element
present. Ethane C2H6
Ethanoic AcidC2H4O2
GlucoseC6H12O6
Molecular Formula It is a multiple of the empirical formula (empirical formula)*n=molecular formula Mr= relative molecular mass Mr= (molecular mass of empirical formula )
For ethane: Empirical formula is CH3 and Mr=30 Mr=(molecular mass )n
30=(12+(3*1.01))n
30=(15.03)n
n=2 Therefore the molecular formula is (CH3)2 or
C2H6
Structural formula
Structural Formula There are three types of structural:
Full structural Shows the bonds of every atom As well as the angle A 2D image
Condensed structural formula Does not show bonds, but groups atoms together The minimum amount of information CH3CH3
Structural formula con’t
Structural Formula Stereochemical
Attempts to show 3D image By convention: a solid enlarging wedge the bond
is coming out of the page A dotted line is going into the page
A compound that contains only C and H◦ When naming it is important to find the longest
unbranched carbon chain First understand what the picture means
What is a hydrocarbon
1
2
3
4
5
6
Carbons?
3
2
2
2
2
3
1 2
3
4
5
6
1 2
3
4
5
6
Hydrogen?
HH
H
HH
HH
H
HH
HH
HH
IUPAC=International union of Pure and Applied Chemistry
# of Carbon IUPAC Name Example
1 Meth- CH4-methane
2 Eth- C2H6-ethane
3 Prop- C3H8-propane
4 But- C4H10-Butane
5 Pent- C5H12-pentane
6 Hex- C6H14-hexane
Side chains are elements or groups of elements attached to the hydrocarbon chain
Also called substituent groups. Important when it comes to naming.
Side chains
Side chain/Substituent
group
IUPAC prefix name
example
-CH3 Methyl CH3CH(CH3)CH3- 2-Methylpropane
-C2H5 Ethyl CH(C2H5)3 3-Ethylpentane
Side chain/Substituent group
IUPAC prefix name
example
-C3H7 Propyl CH(C3H7)3 4-propylheptane
-F,-Cl,-Br,-I Fluoro, chloro, bromo,iodo
CCl4 tetrachloromethane
FUNCTIONAL GROUPS Are specific groups of
atoms within molecules that are responsible for characteristic chemical reactions.
For example: Alcohols are
characterized by their functional group—OH
FUNCTIONAL GROUP 1- ALKANES
ALKANES (CnH2n+2) Alkanes are aliphatic hydrocarbons
They have only carbon-carbon single bonds this means they are saturated hydrocarbons)
Carbon
Hydrogen
ALKANES
Properties of Alkanes: Boiling point are dependent on:
intermolecular forces primarily, like London dispersion forces.
molecular size and surface area of the structure
They do not conduct electricity [because they are molecular compounds]
Are nonpolar so they are not miscible in water
React with oxygen in combustion reactions
1. Find longest unbranched chain of Carbons and number the carbon atoms this is the “root”
2. Based of the number of carbons find the IUPAC name=the suffix
3. Located and identify any sidechains= the prefix
4. Use the attached Carbon To identity where the side group is located.
NAMING (NOMENCLATURE) FOR SIDECHAINS
5. If there is more than 1 of the same kind of branch, use prefixes di, tri, tetra etc. to indicate this.
Place branches in (alphabetical order) in the name
Use commas to separate #s, and "–" to separate letters from #s.
written as:
C# sidechain attached too-sidechainprefixrootofcarbonchain
EXAMPLE
2,5-dimethylhexane
# to identify position of branches
Alkyl prefix
Suffix
Root
# of the alkyl group
Comma to separate the #s
ALKENES- CNH2N
Are unsaturated hydrocarbons [i.e. Have at least one double bond]
– end with suffix “ene” A # must be used to indicate the position of
the double bond. Such as but-2-ene The longest chain must contain the double
bond Physical properties very similar to the alkane
ALKENES- CNH2N- CON’T
tend to have fewer dispersion forces than alkanes, which allows them to be liquids at room temp, rather than solids
If there are two double bonds, then use the prefix “di” before the “ene”and indicate the placement of the double bonds with #’s, Three double bonds requires the prefix “tri” before the “ene”
ALKENES- CNH2N- CON’T
Chemical properties of Alkenes Because of the strain at the location of the
double bond, it is the reactive site of the molecule.
Undergo addition reactions to produce alkanes
H atoms tend to add on to the C atoms involved in the C-C double bond
ALKYNES( CNH2N-2)
Alkynes are also examples of unsaturated hydrocarbons.
They have at least one triple bond Triple bonds are more reactive than double
bonds Alkyne names end with “yne”. Use a number
to indicate the position of the triple bond. Ethyne is the most common alkyne (also
called acetylene)
NAMING AND DRAWING ALKENES AND ALKYNES
Identify the longest continuous chain which includes the double or triple bonds.
Identify the suffix which for alkenes is ``ene`` and for alkynes is ``yne.``
The suffix must also include the location of the double or triple bonds. -2-yne
Number from the end that will give the location of the double or triple bond the lowest value.
NAMING AND DRAWING ALKENES AND ALKYNES
The location of the double or triple bond is indicated by the number of the carbon atom that precedes the bond.
Use a hyphen, a number, a hyphen and then the suffix “ene” or “yne”
Name the side or substituent groups same as done with alkanes.
EXAMPLE
1. find the root- the longest chain of unbranched carbons that contains the double bond 6 Carbon long
2. identify the suffix- remember if it has a double bond the suffix ends with–ene Hexene
3. Number the carbons, so the double bond has the lowest number possible Hex-1-ene
4. identify the prefix- One methyl on C-4, One ethyl on C-4 One methyl on C-5
4,ethyl-4,5-dimethyl
4-ETHYL-4,5-DIMETHYLHEX-1-ENE
The C# that the ethyl is attached too
In alphabetical order the type of side chain or substituent groups attached
The C#s that the methyl is attached too
Indicates the number of the particular side chain
#C in the longest chain on Cs
C# that the double bond is attached too
Indicates double bond
Think about a review game for the stuff we have gone overhave a few practice questions for the board ready as well
Cyclic Hydrocarbons
Alkanes, Alkenes and alkynes that are in rings They have no beginning and no end
Naming and Drawing Hydrocarbons
Root: determine the number of carbon atoms in the ring (do not count those carbons that are part of a side group).
The root name would coincide with this number, preceded by “cyclo”
Suffix: determine if the compound contains all single bonds, at least one double bond, or at least one triple bond.
The suffix will be“ane” “ene” or “yne” respectively.
There are no numbers used to indicate the location of the double or triple bond because it is assumed to be between carbons 1 and 2.
Prefix: Similar to naming the aliphatic hydrocarbons with a few extra things to consider: atoms are not numbered:
if there are no side groups or only one side group
If more than one side group, number the C atoms to give you the lowest number in the name.
If double or triple bonds present in cyclic structure, ALWAYS number so C closest to these bonds is number one.
1.Identify the root: 6 carbons=cyclohex
2.Idenitfy the suffix: double bond present
=ene
3. Assign position numbers of C, so they go in the direction of the side group
4. Name the side group based off of the number of C atoms present
2=ethyl
Name
4-ethylcyclohexene
1
24
3
5
6
1.Identify the root: 6 carbons=cyclohex
2.Idenitfy the suffix: double bond present
=ene
3.Assign position numbers
4. Name side groups
one carbon=methyl
3 methyl sidegroups=trimethyl
5. Locations of side groups: 1,2,4
Name:
1,2,4-trimethylcyclohexene
6 1 5
2 4 3
More practice
1.Identify the root: 4 carbons=cyclobut
2.Idenitfy the suffix: triple bond present
=yne
3.Assign position numbers
4. Name side groups
one florine=floro
5. Locations of side groups: 1
Name:
1-florocyclobutyne
F
3 2
4 1
Oil Sands fun!
In general to remember, Oil sands are transported in hydrotransport
pipelines to prevent sands from dryingBitumen is separated out based on density, then
is skimmed out Bitumen is composed of 20% alkanes and 80%
aromatic=OCHEMBitumen is separated into petroleum and other
useful products Through coking(removing C) and hydrocraking (adding H)
petroleum is produced
Refining petroleum
The process of fractional distillation 1. heat the petroleum 2. the vapor rises up the fractional distillation tower
and then gradually cools 3. each Hydrocarbon component has a unique boiling
point, so it condenses at different times So different components can be removed at different
times
Structural Isomers
Structural isomers: have the same molecular formula but different structures. Because of different structures, different physical
properties exist as well
As the number of carbon atoms increase the number of possible isomers also increases Pentane (C5H10)= 3 Isomers Hexanes (C6H14)= 5 Isomers Heptane (C7H16)= 9 Isomers Nonane (C9H20)=35 Isomers
Homologous Series
REMEMBER** Members in a Homologous series differ by a mthylene
group (CH2) Homologous series can be thought of as families
The mp. and bp. increase as the number of C atoms increase because there is an difference in strength of the LD forces (or van der Waal’s forces)
The mp. and bp. also differ in some cases depending on polarity or hydrogen bonding.
Organics in General
Most organic compounds are non-polar and therefore insoluable in water(polar)
** Like dissolves like**Solubility decreases as chain length increasesIf an organic compound contains a functional
group, it may allow it to hydrogen bond with water, and relatively water soluble