Tertiary Alcohols

Definition

Tertiary alcohols are a class of organic compounds where the hydroxyl (-OH) group is attached to a carbon atom that is connected to three other carbon atoms. This unique structural feature gives tertiary alcohols distinct properties and reactivity patterns compared to primary and secondary alcohols.

5 Must Know Facts For Your Next Test

1. Tertiary alcohols are resistant to oxidation due to the lack of hydrogen atoms on the carbon bearing the hydroxyl group.
2. Tertiary alcohols can undergo dehydration reactions to form alkenes, a process that is facilitated by the stability of the resulting carbocation intermediate.
3. In the preparation of alkyl halides from alcohols, tertiary alcohols undergo a substitution reaction more readily compared to primary and secondary alcohols.
4. The steric hindrance around the hydroxyl group in tertiary alcohols makes them less reactive towards nucleophilic substitution reactions.
5. Tertiary alcohols are commonly used as intermediates in organic synthesis and can be converted to other functional groups through various chemical transformations.

Review Questions

• Explain how the structural features of tertiary alcohols influence their reactivity in the preparation of alkyl halides.
  • The presence of three alkyl groups attached to the carbon bearing the hydroxyl group in tertiary alcohols creates significant steric hindrance. This steric effect makes the carbon more susceptible to nucleophilic attack, facilitating the substitution of the hydroxyl group with a halide ion during the preparation of alkyl halides. The stability of the resulting carbocation intermediate also contributes to the ease of this reaction for tertiary alcohols compared to primary and secondary alcohols.
• Analyze the role of oxidation in the reactivity of tertiary alcohols.
  • Tertiary alcohols are resistant to oxidation due to the lack of hydrogen atoms on the carbon bearing the hydroxyl group. This structural feature prevents the formation of an aldehyde or ketone intermediate, which is typically the first step in the oxidation of primary and secondary alcohols. As a result, tertiary alcohols are more stable and less reactive towards oxidation reactions compared to other alcohol types. This property influences their behavior in various organic transformations, such as the selective oxidation of alcohols.
• Evaluate how the dehydration of tertiary alcohols can be used to synthesize alkenes, and explain the mechanism involved.
  • The dehydration of tertiary alcohols is a useful reaction for the synthesis of alkenes. The mechanism involves the formation of a stable tertiary carbocation intermediate, which is facilitated by the three alkyl groups surrounding the carbon bearing the hydroxyl group. This carbocation can then be attacked by a nucleophile, such as a water molecule, leading to the elimination of water and the formation of an alkene. The stability of the carbocation intermediate is a key factor that makes the dehydration of tertiary alcohols a favorable and widely used reaction in organic synthesis.

Related terms

Alkyl Halides:

Alkyl halides are organic compounds where a halogen atom (such as chlorine, bromine, or iodine) is covalently bonded to an alkyl group.

Oxidation:

Oxidation is a chemical reaction that involves the loss of electrons, resulting in an increase in the oxidation state of an element.

Dehydration:

Dehydration is a chemical reaction where a molecule of water is removed from a compound, often resulting in the formation of a new compound.