Hydrocarbons
Hydrocarbons are a class of molecules that contain only carbon and hydrogen atoms. Some of them make very good fuels. Gasoline contains a mixture of hydrocarbons. Unsaturated hydrocarbons, which contain one or more double bonds, are useful chemicals for many reactions.
Linear saturated hydrocarbons
The simplest hydrocarbons are linear molecules in which each carbon atoms is bonded to two other carbons atoms, in a linear fashion, except for the carbon atoms at the ends, which are only bonded to one other carbon atom. Saturated hydrocarbon names generally end with the suffix "ane" which distinguishes them from unsaturated hydrocarbons, which end with the suffix "ene".
Linear saturated hydrocarbons are referred to as paraffins or alkanes. Their general formula is CnHn+2.
| Name | Formula | CnH2n+2 |
|---|---|---|
| Methane | CH4 | CH4 |
| Ethane | CH3–CH3 | C2H6 |
| Propane | CH3–CH2–CH3 | C3H8 |
| Butane | CH3–(CH2)2–CH3 | C4H10 |
| Pentane | CH3–(CH2)3–CH3 | C5H12 |
| Hexane | CH3–(CH2)4–CH3 | C6H14 |
| Heptane | CH3–(CH2)5–CH3 | C7H16 |
| Octane | CH3–(CH2)6–CH3 | C8H18 |
| Nonane | CH3–(CH2)7–CH3 | C9H20 |
| Decane | CH3–(CH2)8–CH3 | C10H22 |
Linear unsaturated hydrocarbons
Unsaturated hydrocarbons are useful precursor molecules for many reactions. Because they contain one or more double bonds, a large variety of chemical transformations are possible. Unsaturated hydrocarbons generally end with the "ene" suffix, although common names are sometimes used instead of the IUPAC designation. In addition, a numerical prefix is used to indicate the position of the double bond(s).
Linear unsaturated hydrocarbons containing a single double bond are referred to as olefins or alkenes. Their general formula is CnH2n.
| Name | Formula | CnH2n |
|---|---|---|
| Ethene | CH2=CH2 | C2H4 |
| Propene | CH2=CH-CH3 | C3H6 |
| 1-Butene | CH2=CH-CH2-CH3 | C4H8 |
| 2-Butene | CH3-CH=CH-CH3 | C4H8 |
| 1-Pentene | CH2=CH-(CH2)2-CH3 | C5H10 |
| 1-Hexene | CH2=CH-(CH2)3-CH3 | C6H12 |
Linear unsaturated hydrocarbons containing two double bonds are referred to as dienes, diolefins or alkadienes. Their general formula is CnH2(n-1) and some example dienes are:
- 1,2-Butadiene: CH2=C=CH-CH3 or C4H6
- 1,2-Pentadiene: CH2=C=CH-CH2-CH3 or C5H8
Cyclic saturated hydrocarbons
Cyclic saturated hydrocarbons