1. Hydrocarbon Rings Hydrocarbons From Earth’s Crust
Chapter
Hydrocarbon Rings
Hydrocarbons From Earth’s Crust

2. Beta-carotene is an important nutrient in carrots that also gives carrots their orange color. The hydrocarbon skeleton of beta- carotene contains hydrocarbon rings. You will learn about hydrocarbon rings and the properties of compounds formed from these rings.
1) Hydrocarbon Rings

3. Within some hydrocarbons… they contain a chain of carbons that have formed a ring.
Cyclic Hydrocarbons: hydrocarbons that contain a hydrocarbon ring.
Predict how a hydrocarbon could form a ring…. Say butane or pentane….
Hydrocarbon Rings

4. Three Ways to Represent Cyclic Hydrocarbons

5. Cyclic Hydrocarbons The simplest is a 3 ring hydrocarbon.
Rings containing up to 20 carbon atoms are found in nature.
The most abundant are rings that contain 5 or 6 carbons.
Cyclic Hydrocarbons

6. These compounds are responsible for the aromas of spices such as vanilla, clove, cinnamon, and ginger.
They are named this because of the pleasant aromas they give off
NOT ALL aromatic compounds have an aroma. Though.
Aromatic Compounds

7. Any compound that contains a benzene ring is an aromatic compound.
Benzene Basic Structure: In a benzene molecule, the bonding electrons between carbon atoms are shared evenly around the ring.
Aromatic Compound

8. What is different about these two benzenes?
Benzene can be shown as switching, or resonating, between two arrangements of alternating double and single bonds.

9. If there are two (or more) equally valid structures for a molecule, resonance occurs.
Benzene and other molecules that have resonance are VERY stable. More stable than molecules that do not have resonance.
Show the resonance of Benzene…
Resonance

10. Substituted Aromatic Compounds
Compounds with a substituent on a benzene ring are named as a derivative of benzene. When benzene is a substituent, it is called a phenyl group.
Substituted Aromatic Compounds

11. The molecules of many dyes include benzene rings.
Aromatic Compounds

12. 2) Hydrocarbons from Earth’s Crust
1) Natural Gas
2) Petroleum
3) Coal
2) Hydrocarbons from Earth’s Crust

13. Natural gas is an important source of alkanes and aliphatic carbons of low molar mass.
Aliphatic Carbons contain no benzene rings.
The most important component of natural gas, methane, burns with a clean, hot flame.
Other common: propane and butane (grills and lighters)
1) Natural Gas

14. More complex hydrocarbons found in petroleum than in natural gas.
It contains MANY types that need to be separated for it to be useful.
We can refine it by distilling it into fractions according to the boiling points of the hydrocarbons. (See next slide)
Next, we use cracking where hydrocarbons are broken down….
2)Petroleum

15. 2) Petroleum

16. 3) Coal Lignite ~50% carbon Bituminous 70–80% carbon
Coal is classified by its carbon content and hardness.
Hardness of coal tends to increase with higher carbon content.
Lignite ~50% carbon
Bituminous 70–80% carbon
Anthracite >80% carbon

17. Coal consists largely of condensed aromatic compounds of extremely high molar mass.

18. Use this time to complete your Chapter 22 Section Assessments.
Completed Labs are due today. Turn those in by the end of class.
The rest of class…