Ketones. Aldehydes, Amides, Carboxylic Acids, and Esters All Contain a Carbonyl Croup

KETONES, ALDEHYDES, AMIDES, CARBOXYLIC ACIDS, AND ESTERS ALL CONTAIN A CARBONYL CROUP 

The carbonyl group consists of a carbon atom double-bonded to an oxygen atom. It occurs in the organic compounds known as ketones, aldehydes, amides, carboxylic acids, and esters. 

Tannins are responsible for the brown stains in coffee mugs or on a coffee drinkers teeth. Because tannins are acidic, they can be readily removed with an alkaline cleanser. Use a little laundry bleach on the mug, and brush your teeth with baking soda. 

The negative charge of the carboxylate ion is able to pass back and forth between the two oxygen atoms of the carboxyl group. 

An ester is an organic molecule similar to a carboxylic acid except that in the ester the hydroxyl hydrogen is replaced by a carbon. Unlike carboxylic acids, esters are not acidic because they lack the hydrogen of the hydroxyl group. Like aldehydes, many simple esters have notable fragrances and are used as flavorings. Some familiar ones are listed in Table 12.4. 

TABLE 12.4 SOME ESTERS AND THEIR FLAVORS AND ODORS 

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