In the name, “ene” comes before “yne” because of alphabetization.In the case where each would have the same position number, the double bond takes the lower number.In a molecule with both a double and a triple bond, whichever is closer to the end of the chain determines the direction of numbering.Alkenes and alkynes are considered to have equal priority.1 2 3 4 CH2=CHCH2CH3đ-butene but-1-ene CH3CH=CHCH3Ē-butene but-2-ene CH3CCCH3 2-butyne but-2-yne Naming Alkenes and Alkynes When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to the double or triple bond.

If more than one multiple bond is present, identify the position of each multiple bond and use the appropriate ending diene, triene, tetraene, and so forth. Indicate the position of the multiple-bond carbon. Use commas to separate numbers, and hyphens to separate words from numbers. Step 3: Assign numbers and names to the branching substituents, and list the substituents alphabetically.The number indicates which carbon the multiple bond is AFTER. If the multiple bond is an equal distance from both ends, begin numbering at the end nearer the first branch point. Step 2: Number the carbon atoms in the parent chain, beginning at the end nearest to the double or triple bond. Find the longest chain containing the double or triple bond, and name the parent compound by adding the suffix –ene or –yne to the name of the main chain. IUPAC nomenclature rules for alkenes and alkynes are similar to alkanes.Naming an alkyne is similar to the alkenes, except the base name ends in –yne.An alkyne is a hydrocarbon with at least one carbon to carbon triple bond.The base name is given a number which identifies the location of the double bond.The carbons are numbered so as to keep the number for the double bond as low as possible.The longest continuous chain must contain the double bond.Naming is similar to naming alkanes except: Nomenclature of Alkenes -'ene' used for double bond -double bond must have lowest possible number -branching rules same as alkanes -longest chain must include double bond Functional groups usually have multiple bonds or lone pairs of electrons that make them very reactive.The atom or group of atoms that are added to the hydrocarbon are called functional groups.This means it does not have the maximum number of hydrogen atoms as it would if it were an alkane (a saturated hydrocarbon).Īlkenes can also add to each other in an addition reaction to form long chains of carbon compounds.The alkenes are unsaturated with respect to hydrogen.To show the presence of the double bond, the –ane suffix from the alkane name is changed to –ene.Alkenes are hydrocarbons with at least one double carbon to carbon bond.contain carbon-carbon double and triple bond to which more hydrogen atoms can be added.Alkenes and Alkynes Chapter 3 -Nomenclature (naming) of Alkenes -Addition Polymers -Alkynes -Aromatic Hydrocarbons

Ipack naming of polymers