Slide Bài tập ACIDCARBOXYLIC

rboxylic acids are commonly named as indicated in the table below. Although rarely used, IUPACrecommended names also exist. For example, butyric acid (C3H7CO2H) is, according to IUPAC guidelines, also known as butanoic acid.2 To more easily understand much of the below discussion of reactions involving carboxylic acids it can be helpful to notice that the carboxyl group itself is a hydroxylated carbonyl group meaning that two of the carbon atoms four bonds are to an oxygen atom, the carbon atoms third bond is to a second oxygen atom (whose other bond is to a hydrogen atom), and the carbon atoms fourth bond attaches to R. A carbon atom double bonded to an oxygen atom is a carbonyl group and two of the carbon atoms bonds remain available for bonding. A hydrogen atom bonded to an oxygen atom is a hydroxyl group with the oxygen atoms second bond available for bonding. The carboxylate anion RCOO− is usually named with the suffix ate, so acetic acid, for example, becomes acetate ion. In IUPAC nomenclature, carboxylic acids have an oic acid suffix (e.g., octadecanoic acid). For trivial names, the suffix is usually ic acid (e.g., stearic acid).