Ethylenetetracarboxylic dianhydride is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with formula , that can be seen as the twofold

anhydride An organic acid anhydride is an acid anhydride that is an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the pa ...

of ethylenetetracarboxylic acid . It has a bicyclic molecular structure consisting of two

maleic anhydride Maleic anhydride is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid. It is a colorless or white solid with an acrid odor. It is produced industrially on a large scale for applications in coatings and pol ...

rings fused by their respective

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic ...

units. It is a pale yellow oily liquid, soluble in

dichloromethane Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour is widely used as a solvent. Although it is not miscible wit ...

and

chloroform Chloroform, or trichloromethane, is an organic compound with formula C H Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various ...

. The compound and its reactions were first reported in 1967. Jürgen Sauer, Barbara Schröder, Richard Wiemer (1967), ''Eine Studie der Diels-Alder-Reaktion, VI. Kinetischer Nachweis des Moleküls C₆O₆ (Dianhydrid der Äthylentetracarbonsäure)''. Chemische Berichte Volume 100 Issue 1, Pages 306-314 Jürgen Sauer, Barbara Schröder, Albrecht Mielert (1967), ''Eine Studie der Diels-Alder-Reaktion, VII. Reaktionen des Dianhydrids der Äthylentetracarbonsäure (C₆O₆)''. Chemische Berichte Volume 100 Issue 1, Pages 315-322 More recently developed reactions for its synthesis include

pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements '' ...

of ethylenetetracarboxylic acid John M. Patterson, Nabeel F. Haidar, Loren L. Braun and Walter T. Smith, Jr. (1981), ''The pyrolytic behavior of ethylenetetracarboxylic acid''. Journal of Analytical and Applied Pyrolysis, Volume 2, Issue 4, Pages 331-337 : Ethylenetetracarboxylic dianhydride via acid dehydration

Ethylenetetracarboxylic dianhydride via acid dehydration

and

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...

of solid

Meldrum's acid Meldrum's acid or 2,2-dimethyl-1,3-dioxane-4,6-dione is an organic compound with formula . Its molecule has a heterocyclic core with four carbon and two oxygen atoms; the formula can also be written as . It is a crystalline colorless solid, spa ...

. Avat (Arman) Taherpour (2010), ''Microwave-assisted solid phase conversion study of Meldrum’s acid to ethylenetetracarboxylic dianhydride (C₆O₆)'' Spectrochimica Acta Part A, volume 75, pages 493–497. In this latter route, two molecules of the Meldrum's acid are believed to undergo a reductive dimerization to give an alkene linkage with one "Meldrum's acid" ring on each end. The rings then open via

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysi ...

of the esters to form ethylenetetracarboxylic acid, and then the carboxylic acid units recyclize with different partners ('' cis'' on each side of the alkene) as in the simple pyrolysis of the tetra-acid. :

References

{{Oxides of carbon Carboxylic anhydrides Oxocarbons Heterocyclic compounds with 2 rings Oxygen heterocycles

See also

References