Common Names of Carboxylic acids E. For historical reasons having to do with the fact that many carboxylic acids were among the first organic compounds to be isolated and purified, IUPAC rule make allowance for a large number of Well-entrenched common namesOrganic Chemistry Organic Chemistry Xiamen Xiamen University University Common Names of Carboxylic acids For historical reasons having to do with the fact that many carboxylic acids were among the first organic compounds to be isolated and purified, IUPAC rule make allowance for a large number of well-entrenched common names