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🥼organic chemistry review

Primary Alcohol

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

A primary alcohol is an organic compound containing a hydroxyl (-OH) functional group attached to a saturated carbon atom that is bonded to only one other carbon atom. Primary alcohols are an important class of organic compounds with diverse applications and are a key focus in the study of organic chemistry.

5 Must Know Facts For Your Next Test

  1. Primary alcohols can be converted to aldehydes and carboxylic acids through oxidation reactions.
  2. The hydroxyl group in primary alcohols makes them polar and able to form hydrogen bonds, resulting in higher boiling points compared to alkanes of similar molecular weight.
  3. Primary alcohols can be prepared through the reduction of aldehydes and ketones, as well as through the Grignard reaction with carbonyl compounds.
  4. The naming of primary alcohols follows the IUPAC system, where the parent hydrocarbon chain is identified, and the position of the hydroxyl group is indicated by a number.
  5. Primary alcohols are widely used in the production of solvents, fuels, plastics, and various other chemical products.

Review Questions

  • Explain the key structural features that distinguish primary alcohols from other types of alcohols.
    • The defining structural feature of primary alcohols is that the hydroxyl (-OH) functional group is attached to a saturated carbon atom that is bonded to only one other carbon atom. This is in contrast to secondary alcohols, where the hydroxyl group is attached to a carbon bonded to two other carbons, and tertiary alcohols, where the hydroxyl group is attached to a carbon bonded to three other carbons. These structural differences lead to variations in the chemical and physical properties of the different alcohol types.
  • Describe the common methods for the preparation of primary alcohols from carbonyl compounds.
    • Primary alcohols can be prepared through the reduction of aldehydes and ketones, as well as through the Grignard reaction. In the reduction of carbonyl compounds, the use of reducing agents like sodium borohydride (NaBH$_4$) or lithium aluminum hydride (LiAlH$_4$) can selectively convert the carbonyl group to a primary alcohol. The Grignard reaction involves the reaction of an alkyl or aryl Grignard reagent (R-MgX) with a carbonyl compound, producing a primary alcohol as the final product.
  • Analyze the role of primary alcohols in the preparation of aldehydes and ketones, and explain the significance of this relationship.
    • Primary alcohols are closely linked to the preparation of aldehydes and ketones in organic chemistry. Through oxidation reactions, primary alcohols can be converted to the corresponding aldehydes, and further oxidation can lead to the formation of carboxylic acids. This interconversion between primary alcohols, aldehydes, and carboxylic acids is a fundamental concept in understanding the reactivity and transformations of organic compounds. The ability to selectively oxidize primary alcohols to aldehydes is particularly important in the synthesis of various organic molecules and in the study of metabolic pathways involving these functional groups.