Update to RIFM fragrance ingredient safety assessment, isobutyric acid, CAS Registry Number 79-31-2
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IUPAC names of carboxylic acids are systematically derived following a few rules discussed below.
For acyclic saturated monocarboxylic acids, the longest hydrocarbon chain containing the –COOH carbon is identified as the parent chain. Then, the last -e of the parent hydrocarbon name is replaced with a suffix -oic acid.
Numbering the parent carbon chain is performed starting from the –COOH carbon. The names and positions of the substituent are then listed alphabetically as a prefix to the...
Carboxylic acid derivatives such as acid halides, anhydrides, esters, and amides undergo nucleophilic acyl substitution reactions with varying degrees of reactivity.
A key factor in assessing the reactivity of the acid derivatives is the basicity of the substituent or the leaving group. The lower the basicity of the leaving group, the higher the reactivity of the derivative. The basicity of the leaving group follows this order:
Halide ions < Acyloxy ions < Alkoxy ions < Amine ions
Naming Acid Halides
The IUPAC and common names of acid halides are derived from the corresponding carboxylic acids, by changing “ic acid” to “yl halide.” For example, as shown below, the IUPAC name ethanoyl chloride is derived from ethanoic acid, and the common name, acetyl chloride, is obtained from acetic acid.
IUPAC:
Ethanoic acid
Ethanoyl chloride
Common:
Acetic acid
Acetyl chloride
Cyclic acid halides are named by replacing the...
Aldehydes are named based on the systematic nomenclature rules set by the IUPAC. For acyclic aldehydes, the longest carbon chain containing the aldehydic (–CHO) group is considered the parent chain. The aldehyde is named by replacing the last letter “e” in the hydrocarbon name with “al”. For instance, a simple, seven-carbon-membered acyclic aldehyde is called heptanal, derived from heptane. The carbon chain is numbered starting from the aldehydic carbon, although the aldehydic...
The Fischer esterification reaction was developed by the German chemist Emil Fischer in 1895. It is a condensation reaction between carboxylic acids and alcohols in an acidic medium to give esters and water.
Hydroxy-functionalized carboxylic acids undergo intramolecular Fischer esterification to form lactones. The cyclic five- and six-membered lactones are formed spontaneously.
The reaction rate of Fischer esterification is greatly dependent on steric factors. Primary alcohols react fastest...
Carboxylic acids react with alcohols to yield esters via an acid-catalyzed condensation reaction called Fischer esterification. This is a nucleophilic acyl substitution reaction that proceeds via a tetrahedral intermediate, where a water molecule is eliminated as the leaving group.
The mechanism of this reaction was confirmed by Robert and Urey (1938) through a radioisotope labeling experiment, where esterification of a carboxylic acid was carried out using 18O-labeled alcohol. The...

