Acid Chloride Nomenclature: Videos & Practice Problems

Acid chlorides, also known as acyloids, are named using two different conventions: common naming and IUPAC naming. Understanding the distinction between these two methods is essential for accurately identifying these compounds.

To illustrate the naming process, consider a three-carbon acid chloride. For the common name, you start with the corresponding carboxylic acid. In this case, the three-carbon carboxylic acid is propionic acid. To convert this to the common name for the acid chloride, you replace the "ic acid" ending with "yl chloride." Thus, propionic acid becomes propanyl chloride.

In contrast, the IUPAC naming convention begins with the alkane name corresponding to the carbon chain. For a three-carbon chain, the base name is propane. To form the IUPAC name for the acid chloride, you remove the "e" from propane and add the suffix "oyl chloride." Therefore, propane becomes propanoyl chloride.

In summary, the common name for a three-carbon acid chloride is derived from the carboxylic acid by replacing "ic acid" with "yl chloride," while the IUPAC name is formed by modifying the alkane name by removing the "e" and adding "oyl chloride." This systematic approach to naming acid chlorides is crucial for effective communication in organic chemistry.

In organic chemistry, the naming conventions for acid chlorides closely follow those of carboxylic acids, with some important distinctions. When applying IUPAC nomenclature, the presence of a carbonyl group (C=O) takes precedence over alcohol groups. For instance, when naming a compound with two carbons and a chlorine substituent, the correct IUPAC name is 2-hydroxyethanoyl chloride. This reflects the priority of the carbonyl over the hydroxyl group, which is a shift from previous conventions where alcohols were often prioritized.

In contrast, the common name for this compound would be alpha-hydroxyacetyl chloride, indicating that the hydroxyl group is on the alpha carbon relative to the carbonyl. The use of Greek letters, such as alpha (α) and gamma (γ), is essential in distinguishing the positions of substituents in organic molecules. For example, if a substituent is located two carbons away from the carbonyl, it would be referred to as a gamma (γ) substituent.

Understanding these naming conventions is crucial for accurately communicating the structure and properties of organic compounds. The priority of functional groups, particularly carbonyls, plays a significant role in determining the correct nomenclature and should be kept in mind when studying acid chlorides and their derivatives.

Valeryl chloride is an organic compound characterized by a five-carbon chain (pentane) with a chlorine atom attached to the terminal carbon. The structure can be represented as follows:

Valeryl chloride:

In the context of substituents, the term "gamma ethyl" refers to the placement of an ethyl group at the gamma position of the carbon chain. In a five-carbon chain, the carbon atoms are numbered from one end to the other, with the first carbon being the alpha position, the second the beta, and the third the gamma. Therefore, to draw the compound with an ethyl group at the gamma position, you would add the ethyl group to the third carbon of the valeryl chloride structure.

This results in a compound that can be visualized as follows:

Gamma ethyl valeryl chloride:

Understanding the structure and naming conventions of organic compounds like valeryl chloride and its derivatives is essential for grasping the fundamentals of organic chemistry.