Alcohols and Phenols and how to identify them

2 Classification Primary: carbon with –OH is bonded to one other carbon Secondary: carbon with –OH is bonded to two other carbons Tertiary: carbon with –OH is bonded to three other carbons Aromatic (phenol): -OH is bonded to a benzene ring

3 Classify these:

4 IUPAC Nomenclature Find the longest carbon chain containing the carbon with the -OH group Drop the -e from the alkane name, add –ol Number the chain, starting from the end closest to the -OH group Number and name all substituents. =>

Chapter 105 Name these: 2-methyl-1-propanol 2-methyl-2-propanol 2-butanol 3-bromo-3-methylcyclohexanol =>

6 Naming Phenols -OH group is assumed to be on carbon 1 For common names of disubstituted phenols, use ortho- for 1,2; meta- for 1,3; and para- for 1,4 Methyl phenols are cresols. 3-chlorophenol meta-chlorophenol 4-methylphenol para-cresol

7 Physical Properties Unusually high boiling points due to hydrogen bonding between molecules Small alcohols are miscible in water, but solubility decreases as the size of the alkyl group increases.

Acidity of Phenol In water, phenol acts as a weak acid phenol phenoxide ion

Oxidation of Alcohols: Do I have a tertiary alcohol? For Primary alcohols that dehydrogenate from the aldehyde to the carboxylic acid tertiary alcohols do not dehydrogenate (oxidize) Secondary alcohols only oxidize to the ketone 9 If chromic acid is used for H 2 CrO 4 =[O] then the product includes Cr 3+ which is green + Cr 3+

Oxidation with Chromate Negative test tertiary alcohol Positive test primary or secondary alcohol

Test of a Phenol: FeCl 3 test You can test for a phenol with ferric chloride (FeCl 3 ) Phenol + Fe 3+  [Fe 3+.phenol complex] colorless yellow purple

Experiment You will test the following ethanol 2-propanol 2-methyl-2-propanol Cyclohexanol Phenol Unknown

Experiment Odor Solubility in water Acidity Reaction with Chromic Acid Ferric Chloride Test Use test results to identify your unknown