{"id":1447,"date":"2018-03-21T15:08:35","date_gmt":"2018-03-21T15:08:35","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-orgbiochemistry\/chapter\/aldehydes-and-ketones-structure-and-names\/"},"modified":"2018-10-31T15:26:05","modified_gmt":"2018-10-31T15:26:05","slug":"aldehydes-and-ketones-structure-and-names","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-monroecc-orgbiochemistry\/chapter\/aldehydes-and-ketones-structure-and-names\/","title":{"raw":"14.9 Aldehydes and Ketones: Structure and Names","rendered":"14.9 Aldehydes and Ketones: Structure and Names"},"content":{"raw":"
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Learning Objectives<\/h3>\r\n
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  1. Identify the general structure for an aldehyde and a ketone.<\/li>\r\n \t
  2. Use common names to name aldehydes and ketones.<\/li>\r\n \t
  3. Use the IUPAC system to name aldehydes and ketones.<\/li>\r\n<\/ol>\r\n<\/div>\r\nThe next functional group we consider, the <\/span>carbonyl group<\/span><\/span>, has a carbon-to-oxygen double bond.<\/span>\r\n\r\n<\/div>\r\n
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    Carbonyl groups define two related families of organic compounds: the aldehydes and the ketones.\u00a0 The carbonyl group is also found in Carboxylic acids, esters, and amides, which will be discussed in other sections.<\/p>\r\n\r\n

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    Note<\/h3>\r\n

    The carbonyl group is ubiquitous in biological compounds. It is found in carbohydrates, fats, proteins, nucleic acids, hormones, and vitamins\u2014organic compounds critical to living systems.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n

    In a ketone<\/span><\/span>, two carbon groups are attached to the carbonyl carbon atom. The following general formulas, in which R represents an alkyl group and Ar stands for an aryl group, represent ketones.<\/p>\r\n\r\n

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    In an aldehyde<\/span><\/span>, at least one of the attached groups must be a hydrogen atom. The following compounds are aldehydes:<\/p>\r\n\r\n

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    In condensed formulas, we use CHO to identify an aldehyde rather than COH, which might be confused with an alcohol. This follows the general rule that in condensed structural formulas H comes after the atom it is attached to (usually C, N, or O).<\/p>\r\n\r\n

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    The carbon-to-oxygen double bond is not shown but understood to be present.<\/p>\r\n

    Because they contain the same functional group, aldehydes and ketones share many common properties, but they still differ enough to warrant their classification into two families.<\/p>\r\n\r\n

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    Naming Aldehydes and Ketones<\/h2>\r\n

    Both common and International Union of Pure and Applied Chemistry (IUPAC) names are frequently used for aldehydes and ketones, with common names predominating for the lower homologs. The common names of aldehydes are taken from the names of the acids into which the aldehydes can be converted by oxidation. (For more information about carboxylic acids, see Chapter 15 \"Organic Acids and Bases and Some of Their Derivatives\"<\/a>, Section 15.2 \"Carboxylic Acids: Structures and Names\"<\/a> through Section 15.4 \"Physical Properties of Carboxylic Acids\"<\/a>.)<\/p>\r\n\r\n

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    Note<\/h3>\r\n

    The stems for the common names of the first four aldehydes are as follows:<\/p>\r\n\r\n