Benzoquinonetetracarboxylic acid
In chemistry, 1,4-benzoquinonetetracarboxylic acid is an organic compound with formula , or (C6O2)(-(CO)OH)4, which can be viewed as deriving from para-benzoquinone  through replacement of the four hydrogen atoms by carboxyl functional groups -(CO)OH. By removal of four protons, the acid is expected to yield the anion , benzoquinonetetracarboxylate, which is one of the oxocarbon anions (consisting solely of oxygen and carbon). By loss of 1 through 3 protons, it forms the anions , , and , called respectively trihydrogen-, dihydrogen-, and hydrogenbenzoquinonetetracarboxylate. The same names are used for the corresponding esters. Removal of two water molecules gives the compound benzoquinonetetracarboxylic dianhydride, , one of the oxides of carbon. The acid can be obtained by from durene (1,2,4,5-tetramethylbenzene) via dinitropyromellitic and
diaminopyromellitic acids. See also
 Mellitic acid 
 Tetrahydroxybenzoquinone 
 Benzenehexol

References

1,4-Benzoquinones
Carboxylic acids