Multiple Bonds

 Multiple Bonds

Alkanes have singular bonds. What are molecules with double bonds called? Triple Bonds?

Multiple Bonds
DEFINE: an organic compound containing a carbon-carbon double/triple bond. This is known as an Alkene, or and Alkyne.

EXAMPLES:











In order: propene, 2-butene, propyne, 2-butyne, 3,3-dimethyl-1-cyclopentane, 4-chloro-2-hexyne, 1,3-dibromo-3-hexene

The naming of compounds with double and triple bonds has a few rules

RULES:
 * If a double bond is present, change the ‘ane’ ending of the parent hydrocarbon to ‘ene.’
 * If a triple bond is present, change the ‘ane’ ending of the parent hydrocarbon to ‘yne’
 * Use a number to indicate the lower numbered hydrocarbon involved in the bond (the bond goes FROM the lowered numbered carbon TO the higher numbered carbon.) The number goes immediately in front of the name of the parent hydrocarbon, separated by a dash.
 * Number the parent hydrocarbon to give the double/triple bond the lowest possible number. If the number is the same starting from either end, start the numbering from the end closest to the first branch point.

Uses

 * Alkenes are used in the manufacturing of plastic
 * Lower alkenes are used as fuel and illuminant
 * Alkenes can also ripen fruit artifically
 * Acetylene, or ethyne, is a widely used alkyne that can go under multiple chemical reactions in manufacturing products
 * Propyne can be used as fuel in welding torches

Hints and Facts
NOTE: A simple way to remember the endings is:
 * Single bonds, ‘-ANE’
 * Double bonds ‘-ENE’
 * Triple bonds ‘-YNE’

Alkenes and Alkynes are unsaturated hydrocarbons because they have less hydrogen atoms than alkanes. Alkanes are said to be saturated hydrocarbons because they contain the maximum amount of hydrogens possible.

Try it yourself!
EXERCISES: Name the following:

1)





Draw the following:

2a) 1-hexene b) 3-decene c) 2-heptyne d) 1-octyne

ANSWERS:

1) 2-methyl-1-butene, 3,3-dimethyl-1-pentane, 2-butyne, 4-methyl-1-pentyne

2)