Alcohols-2

Objectives of the Lesson

• To learn IUPAC naming rules of alcohols

• To be able to give the names of alcohols

​The following procedure should be followed to name alcohols according to the IUPAC system.

1. Select the longest continuous carbon chain to which the hydroxyl group is attached. Change the name of the alkane corresponding to this chain by dropping the final –e and adding the suffix –ol.

2. Number the carbon atoms in the longest continuous carbon chain starting from the end nearest to the hydroxyl group.

3. The carbon atom bearing the hydroxyl group takes the lowest number. Indicate the position of the hydroxyl group by using this number; indicate the position of other substituents (as prefixes) by using the numbers corresponding to their positions along the carbon chain.

​4. For straight chained compounds,

• if the -OH is attached to the first carbon, instead of number “1”, the letter “n”, meaning normal, can be used.

• If the -OH group is attached to an unsaturated hydrocarbon chain, the number of the carbon bearing the -OH group is substituted between the name of hydrocarbon and the suffix –ol.

• If the -OH group is attached to the first carbon of the unsaturated hydrocarbon chain, the number of the carbon bearing the -OH group is not written.

​5. If the -OH group is in the middle of the chain, the numbering of the carbon atoms starts at the end nearest any branching.

​6. If there are more than one OH group, “di, tri, tetra....” are used before the suffix –ol. The numbers of the carbon atoms bearing -OH groups are written before the name of the alcohol.

Multiple Choice

Name this molecule.

• ethanol

• ethanoic acid

• propanol

• propanoic acid

Multiple Choice

What is the name of compound ?

• Phenol

• Cyclohexane

• Cyclohexanol

• Cyclohexenol

Multiple Choice

Butanol is a member of the homologous series alcohols.

which one of the following is not a formula of butanol?

• C₄H₁₀O

• C₄H₁₀OH

• C₄H₉OH

• CH₃CH₂CH₂CH₂OH

Multiple Choice

Name the following molecule:

• 3,3-dimethyl-1-butanol

• 3,3-methyl-1-butanol

• 2,2-dimethyl-4-butanol

• 3,3,3-trimethyl-1-propanol

Multiple Choice

What is the IUPAC name of the alcohol ?

• 3-etil-2-butanol

• 3-metil-2-pentanol

• 2-etil-3-butanol

• 2-pentanol

Multiple Choice

What is the name of the compound ?

• 2-methyl-6-octanol

• 2-ethyl-6-heptanol

• 6-ethyl-2-heptanol

• 6-methyl-2-octanol

Multiple Choice

Which structure below correspond to 2,3-butandiol ?

• CH₃-CH₂OH-CHOH-CH₃

• CH₃-CHOH-CH₂-CH₂OH

• CH₃-CHOH-CHOH-CH₃

Multiple Choice

What is the name of the alcohol?

• hex-4-yn-1-ol

• hept-4-yn-1-ol

• hept-1-yn-4-ol

• hex-1-yn-4-ol

Multiple Choice

What is the name of the compound ?

• hex-2-en-5-ol

• hex-5-en-2-ol

• hept-5-en-1-ol

• hept-5-en-2-ol

Multiple Choice

What is the name of the compound ?

• 2,2-dimethyloctan-3-ol

• 3,3-dimethyloctan-2-ol

• 1,1-dimethyloctan-3-ol

• 7,7-dimethyloctan-6-ol