Naming Carboxylic Acid Derivatives and Nitriles

Acid halides are named by identifying first the acyl group and then the halide. The acyl group name is derived from the carboxylic acid name by replacing the -ic acid ending with -yl or the -carboxylic acid ending with -carbonyl. For example  

Symmetrical anhydrides of unsubstituted monocarboxylic acids and cyclic anhydrides of dicarboxylic acids are named by replacing the word acid with anhydride  

Anhydrides derived from substituted monocarboxylic acids are named by adding the prefix bis- (meaning two) to the acid name  

Unsymmetrical anhydrides—those prepared from two different carboxylic acids—are named by citing the two acids alphabetically  

Acetyl chloride Benzoyl bromide (from acetic acid) (from benzoic acid) 

Acetic anhydride Benzoic anhydride Succinic anhydride 

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Nitriles are classified as carboxylic acid derivatives because they are converted to carboxylic acids on hydrolysis. The conditions required are similar- to those for the hydrolysis of amides, namely, heating in aqueous acid or base for several hours. Like the hydrolysis of amides, nitrile hydrolysis is ineversible in the presence of acids or bases. Acid hydrolysis yields fflnmonium ion and a carboxylic acid. 

Nitriles, RC=N, are considered derivatives of carboxylic acids because the nitrile carbon is in the same oxidation state as the carboxy carbon and because nitriles are readily converted into other carboxylic acid derivatives. This section describes the rules for naming nitriles, the structure and bonding in the nitrile group, and some of its spectral characteristics. Then it compares the chemistry of the nitrile group with that of other carboxylic acid derivatives. 

Solvents can be classified into three categories according to their polarity namely, polar protic, dipolar aprotic and non-polar. Most of the common solvents fall under one of following chemical classes Aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, phenols, ethers, aldehydes, ketones, carboxylic acids, esters, halogen-substituted hydrocarbons, amines, nitriles, nitro-derivatives, amides and sulfur-containing solvents (Marcus, 1998). In certain cases a mixture of two or more solvents would perform better than a single solvent. 

Common names of nitriles are derived from the corresponding carboxylic acids. Begin with the common name of the acid, and replace the suffix -ic acid with the suffix -onitrile. The IUPAC name is constructed from the alkane name, with the suffix -nitrile added. 

A molecule bearing the COOH (carboxyl) unit (see Chapter 16, Section 16.4) is a carboxylic acid, and the name of 27 must reflect this fact. Compormd 27 is benzoic acid, the parent structure for this class. The usual acid derivatives, such as esters (benzoates), acid chlorides (benzoyl chlorides), and amides (ben-zamides), are all known, prepared by methods discussed in Chapter 20. There are also nitrile derivatives, and 28 is named benzonitrile. 

The functional group of a nitrile is a cyano (C=N) group bonded to a carbon atom. lUPAC names follow the pattern alkanenitrile (e.g., ethanenitrile). Common names are derived by dropping the suffix -ic or -oic acid from the name of the parent carboxylic acid and adding the suffix -onitrile. 

Whereas for most compound classes the exemplifications in Table 8 are directly applicable without any difficulty, the two alternative naming methods for aliphatic carboxylic acids and their derivatives as well as for nitriles and aldehydes require more detailed illustration. 

Salts and esters of carboxylic acids and related compounds are named by placing the name of the metal or the esterifying group in front of the name of the acid anion, separated by a space. Joint occurrence of both functions is indicated accordingly. Acid salts and esters are named analogously. Complex cases can also be named more descriptively ... salt or. .. ester of. .. acid. (Similar provisions are valid for other acid derivatives such as amides and nitriles.)... 

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