Aliphatic and Aromatic Hydrocarbons
Works Cited
“Aromatic Compounds and Aromaticity,” UEA. University of East Anglia, 2012. Web. June 1 2014.
<http://www.uea.ac.uk/~c286/aromaticnotes.htm>.
Naming Cyclic Hydrocarbons
Hydrocarbon?
Heptane
Hexane
Pentane
Propane
Naming Aromatic Hydrocarbons
- Organic compounds containing only carbon and hydrogen
- Divided into 2 categories:
- Aliphatic Hydrocarbons
- Aromatic Hydrocarbons.
- Prefix: Cyclo-
- Named by the shape they are formed by
Decane
Properties of Aromatic Hydrocarbons
Odor
ALL aromatic compounds have an odor. Could be heavenly or putrid.
State at SATP
Polarity
- Varies on compounds, can be polar or non-polar
- Symmetrical and non-polar unless they contain a substituent in which will make compound polar
Melting Point
- The bigger the molecule, the lower the melting point
- Melting point of benzene: 5.5
- Melting point of methylbenzene: -95
Boiling Point
- The larger the molecule, the higher the boiling point
- Boiling point of benzene: 8.0
- Boiling point of methylbenzene: 111
Aromatic Hydrocarbons
Aliphatic Hydrocarbons
2nd Method
1st Method
Solubility
- A compound in which contains 1 or more benzene ring
Why?
- Compound consisting of only carbon & hydrocarbon. Joined together in straight chains, branched chains or non-aromatic rings
Used when a benzene ring is a side chain
Used when a benzene ring is the parent molecule
What is a Benzene Ring?
- Flat 6 carbon ring
- 1 hydrogen atom bonded to each carbon atom
- Alternating double bonds
THUS,
A chemical formula of C6H6
2.A)
1.B)
1.C)
1.A)
Unsaturated Aliphatic
Saturated
Aliphatic
Used when there is TWO OR MORE non-carbon or small alkyl group attached to benzene
Used when 1 or more benzene side chains
Used when there are TWO benzene side chains
- Side chains are listed alphabetically
Used when there is ONE non-carbon or small alkyl group attached to benzene
- Numbered according to placement of alkyl group, using lowest possible numbers
EG: ortho dichlorobenzene
EG: 1-ethyl-4-methylbenzene
- At least 1 double bond
- Carbons don't have the maximum number of hydrogen
- Only single bonds
- Carbons contain a maximum number of hydrogen
- Numbered according to placement, using lowest numbers
- Uses prefix's ortho-, meta-, or para- depending on placement
Alkane
Cyclic
Alkyne
Alkene
Carbon atoms join to form a ring
REACTIONS
This is because...
Remember the proposed cyclic structure :C6H6
- Rather than having 3 double bonds and 3 single bonds, benzene would need its valence electrons to be shared equally among all 6 C atoms-->making 6 identical bonds
- So there is no specific location for the shared electrons b/c all of the bond strengths are equal between single and double bonds; so benzene rings do not undergo addition reactions as double bonds do
• Undergo substitution reactions, similar to alkanes
• Benzene rings DO NOT undergo addition reactions except under extreme conditions of temperature and pressure
Substitution Reactions
Reaction in which a hydrogen atom is replaced by another atom or group of atoms