Halogenation: The reaction of an alkane with a halogen (X2 = F, Cl, Br, I) occurs when a mixture of the two is irradiated with ultraviolet light.
Combustion: The reaction of an alkane with O2 occurs during combustion when the alkane is used as a fuel. Carbon dioxide and water are formed as products, and a large amount of heat is released.
An example of a combustion reaction:
CH4 + 2 O2 → CO2 + 2 H2O + Energy
Complete: C2H6 (g) + O2 (g) → CO2 (g) + H2O (g) + Energy
Incomplete: C3H8 (g) + O2 (g) → H2O (g) + CO2 (g) + CO (g) + C (s) + Energy
Petroleum: Complex mixture of alkanes that can be separated into fractions by distillation. Separating molecules based on differences in boiling points is called distillation. When multiple fractions are separated during a single distillation, the process is called fractional distillation.
Refining: Catalytic cracking (kerosene is cracking)
Gasoline, Kerosene, Heating Oil and Diesel Fuel
Gasoline (bp 20-200°C), kerosene (bp 175-275°C), heating oil and/or diesel fuel (bp 250-400°C)
Alkenes: (olefins) They occur abundantly in nature and have many important biological roles. Generalities: Alkenes contain carbon-carbon double bonds – Suffix = -ene. In the carbon-carbon double bond, two pairs of electrons are being shared, leaving the carbon free to bond to two other things. Source: Vitamin A. Ethylene: Plant hormone that introduces ripening in fruit.
Physical properties: They are similar to alkanes. The physical state depends on molecular mass. The simplest alkenes are gases (2-4C). Linear alkenes of approximately five to sixteen carbons are liquids, and higher alkenes are waxy solids.
Boiling point and solubility: They are soluble in non-polar solvents. Insoluble in water. Smaller boiling points than alkanes.
Importance in everyday life: Used as starting materials in the syntheses of alcohols, plastics, lacquers, detergents, and fuels.