Ethylenetetracarboxylic acid

Ethylenetetracarboxylic acid is an organic compound with formula C
₆H
₄O
₈, or (HO(OC)-)₂C=C(-(CO)OH)₂.

Ethylenetetracarboxylic acid

Names
IUPAC name Ethene-1,1,2,2-tetracarboxylic acid
Identifiers
CAS Number	4363-44-4 Y
3D model (JSmol)	Interactive image
ChemSpider	11636515 Y
PubChem CID	12651152
UNII	MV8N94W7XP Y
CompTox Dashboard (EPA)	DTXSID20505724
InChI InChI=1S/C6H4O8/c7-3(8)1(4(9)10)2(5(11)12)6(13)14/h(H,7,8)(H,9,10)(H,11,12)(H,13,14) N Key: AIJZIRPGCQPZSL-UHFFFAOYSA-N N InChI=1/C6H4O8/c7-3(8)1(4(9)10)2(5(11)12)6(13)14/h(H,7,8)(H,9,10)(H,11,12)(H,13,14) Key: AIJZIRPGCQPZSL-UHFFFAOYAE
SMILES O=C(O)/C(C(O)=O)=C(C(O)=O)\C(O)=O
Properties
Chemical formula	C6H4O8
Molar mass	204.090 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

By removal of four protons, the acid yields the anion C
₆O⁴⁻
₈, ethylenetetracarboxylate, which is one of the oxocarbon anions (consisting solely of oxygen and carbon). By loss of 1 through 3 protons, it forms the anions C
₆H
₃O⁻
₈, C
₆H
₂O²⁻
₈, and C
₆HO³⁻
₈, called respectively trihydrogen-, dihydrogen-, and hydrogenethylenetetracarboxylate. The same names are used for the corresponding esters.

The acid can be obtained by hydrolysis of tetraethyl ethylenetetracarboxylate, which in turn can be obtained from diethyl dibromomalonate with sodium iodide.

Ethylenetetracarboxylic dianhydride, a twofold acid anhydride of this compound, can be formed by direct dehydration at high temperature.