Carboxylic acid carbonyl functionalities such as ketone as well as moderately reactive ester, olefin, nitrile, and halide moieties. Carboxylic acid A carboxylic acid is an organic compound that contains a carboxyl group (C(=O)OH). The general formula of a carboxylic acid is R–COOH, with R referring to the rest of the (possibly quite large) molecule. Carboxylic acids occur widely and include the amino acids (which make up proteins) and acetic acid (which is part of vinegar and occurs in metabolism). Salts and esters of carboxylic acids are called carboxylates. When a carboxyl group is deprotonated, its conjugate base forms a carboxylate anion. Carboxylate
Maleic acid Maleic acid Maleic acid or "cis"-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Its chemical formula is HOCCH=CHCOH. Maleic acid is the "cis"-isomer of butenedioic acid, whereas fumaric acid is the "trans"-isomer. It is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, maleic acid has few applications. Maleic acid is a less stable molecule than fumaric acid. The difference in "heat of combustion" is 22.7 kJ/mole. The heat of combustion is -1355 kJ/mole. Maleic acid is more soluble in water than fumaric acid. The