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General Chemistry Principles, Patterns, and Applications, 2011

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Oxygen- <strong>and</strong> Nitrogen-Containing Functional Groups"). Alcohols are classified as primary, secondary, or<br />

tertiary, depending on whether the –OH group is bonded to a primary, secondary, or tertiary carbon. For<br />

example, the compound 5-methyl-3-hexanol is a secondary alcohol.<br />

Ethers, especially those with two different alkyl groups<br />

(ROR′), can be prepared by a substitution reaction in which a nucleophilic alkoxide ion (RO − ) attacks the partially<br />

positively charged carbon atom of the polar C–X bond of an alkyl halide (R′X):<br />

Although<br />

both alcohols <strong>and</strong> phenols have an –OH functional group, phenols are 10 6 –10 8 more acidic than alcohols. This is<br />

largely because simple alcohols have the –OH unit attached to an sp 3 hybridized carbon, whereas phenols have<br />

an sp 2 hybridized carbon atom bonded to the oxygen atom. The negative charge of the phenoxide ion can therefore<br />

interact with the π electrons in the ring, thereby delocalizing <strong>and</strong> stabilizing the negative charge through resonance.<br />

(For more information on resonance, seeChapter 8 "Ionic versus Covalent Bonding", Section 8.5 "Lewis Structures<br />

<strong>and</strong> Covalent Bonding".) In contrast, the negative charge on an alkoxide ion cannot be stabilized by these types of<br />

interactions.<br />

Alcohols undergo two major types of reactions: those involving cleavage of the O–H bond <strong>and</strong> those<br />

involving cleavage of the C–O bond. Cleavage of an O–H bond is a reaction characteristic of an acid, but<br />

Saylor URL: http://www.saylor.org/books<br />

Saylor.org<br />

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