Mellitates

Mellitates are salts or esters of mellitic acid. Mellitic acid, also known as benzenehexacarboxylic acid, has the chemical formula C6(COOH)6. It is a hexacarboxylic acid derived from the aromatic hydrocarbon benzene, where all six hydrogen atoms have been replaced by carboxyl groups. Mellitic acid itself is a white crystalline solid.

Salts of mellitic acid are formed when the acidic hydrogen atoms of the carboxyl groups are replaced by metal cations. For example, a sodium mellitate would have the general formula C6(COONa)6. These salts are typically soluble in water. Esters of mellitic acid are formed by reacting the carboxyl groups with alcohols, replacing the hydrogen atoms with alkyl or aryl groups. A common example would be a trimethyl mellitate, C6(COOCH3)6. Esters of mellitic acid are generally less polar than the acid or its salts and may have different solubility properties.

Mellitic acid and its derivatives are notable for their high degree of carboxylation. They can be synthesized through various oxidation processes, often starting from more complex aromatic compounds or coals. Historically, mellitic acid was isolated from certain types of coal, specifically from the mineral mellite, which is an aluminum salt of mellitic acid. Its structure, with six carboxyl groups on a benzene ring, makes it a unique molecule with potential applications in coordination chemistry and material science due to its ability to form complex structures with metal ions.