1. Cyclic Hydrocarbons
Chemistry 11
Ms. Mcgrath

2. Cyclic Hydrocarbons
Cyclic Hydrocarbons are hydrocarbon ring structures
They occur when the ends of two hydrocarbon chains join together
In order to do so, a hydrogen atom from each end carbon must be removed

3. Drawing - Cyclic Hydrocarbons
Use a line diagram in a ring-like shape
Each carbon-carbon bond is shown as a straight line
Each corner ring represents a carbon atom
Hydrogen atoms are not shown, but they are assumed to be present in the proper amounts

4. Naming - Cyclic Hydrocarbons
Because of the ring structure, the naming rules for cyclic hydrocarbons are slightly different from those of straight chained hydrocarbons
Here are four examples to name cyclic hydocarbons

5. Naming - Cyclic Hydrocarbons Example 1
Use the general formula: prefix + root + suffix
Example:
There are only single carbon-carbon bonds
There are five corners (carbon atoms) in the ring
There are no branches
The name of this compound is: cyclopentane

6. Naming - Cyclic Hydrocarbons Example 2
When naming cycloalkanes, all carbon atoms are treated equally, meaning any carbon can be carbon number 1
In this example, only one branch is attached to the ring therefore the carbon that the branch is attached to is carbon number 1
Because the branch automatically get the gets the lowest position number no position number is required in the name
The name of this compound is: methylcyclohexane

7. Naming - Cyclic Hydrocarbons Example 3
When there are two or more branches, each must have the lowest possible position number
For this example, count the carbon with the ethyl group as carbon 1, then count in a counterclockwise direction
This allows the branches to be in alphabetical order and to add position numbers in ascending order
The name of this compound is: 1-ethyl-3-methylcyclohexane

8. Naming - Cyclic Hydrocarbons Example 4
There is a double bond here, therefore follow the same rules for alkenes (the double bond gets priority for the lowest number)
One of the carbon atoms of the double bond must be carbon number 1
The branch must get the lowest number possible position number
Here, the carbon on the bottom is carbon number 1, then we count counterclockwise so the carbon group containing the methyl group is carbon 3
The name of this compound is: 3-methylcyclohex-1-ene

9. Cyclic Hydrocarbons
Complete
#30, 31 Page 358