Chapter 13 Alcohols, Phenols, and Thiols 13.4 Reactions of Alcohols and Thiols

Combustion of Alcohols Combustion is the reaction of an alcohol with O2 to produce CO2 and H2O.

Dehydration of Alcohols Dehydration of an alcohol occurs when heated with an acid catalyst with the loss of —H and —OH from adjacent carbon atoms alcohol alkene

Saytzeff’s Rule According to Saytzeff’s rule, the dehydration of a secondary alcohol favors the product in which hydrogen is removed from the adjacent carbon atom in the chain with the smaller number of H atoms

Learning Check Write the equations for the reactions when 2-propanol undergoes: A. combustion B. dehydration

Solution A. dombustion: B. dehydration:

Formation of Ethers Ethers form when dehydration takes place at low temperature. two methanol molecules dimethyl ether

Oxidation and Reduction In the oxidation of an organic compound, there is an increase in the number of C—O bonds there is a loss of H In the reduction of an organic compound, there is an decrease in the number of C—O bonds there is a gain of H

Oxidation and Reduction (continued)

Oxidation of Primary (1) Alcohols When a primary alcohol is oxidized [O], one H is removed from the –OH another –H is removed from the carbon bonded to –OH an aldehyde is produced Ethanol (ethyl alcohol) Ethanal (acetaldehyde)

Oxidation of Secondary (2) Alcohols When a secondary alcohol is oxidized [O], one H is removed from the –OH another –H is removed from the carbon bonded to the –OH a ketone is produced 2-Propanone(dimethyl ketone, “acetone”) 2-Propanol (isopropyl alcohol)

Oxidation of Tertiary (3) Alcohols Tertiary alcohols do not readily oxidize. There is no H on the C—OH to oxidize. 2-Methyl-2-propanol

Learning Check Select the compound that would result for each reaction of CH3—CH2—CH2—OH. 1) CH3—CH ═ CH2 2) CO2 + H2O 3) A. H+, heat B. [O] C. O2, heat

Solution Select the compound that would result for each reaction of CH3—CH2—CH2—OH. A. H+, heat 1) CH3—CH ═ CH2 B. [O] 3) C. O2, heat 2) CO2 + H2O

Oxidation of Ethanol in the Body ethanol is oxidized by enzymes in the liver aldehyde product impairs coordination

Ethanol CH3─CH2─OH Ethanol acts as a depressant kills or disables more people than any other drug is metabolized at a rate of 12–15 mg/dL per hour by a social drinker is metabolized at a rate of 30 mg/dL per hour by an alcoholic

Effect of Ethanol on the Body

Learning Check ? 1) CH3—CH ═ CH—CH3 2) 3) CO2 + H2O 4) Select the product from the oxidation of 1) CH3—CH ═ CH—CH3 2) 3) CO2 + H2O 4) ?

Solution Select the product from the oxidation of 2)

Oxidation of Thiols When thiols undergo oxidation, an H atom is lost from two –SH groups the product is a disulfide disulfide