| Acetylenedicarboxylic acid[1] | |
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But-2-ynedioic acid |
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Other names
2-Butynedioic acid |
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| Identifiers | |
| CAS number | 142-45-0 |
| PubChem | 371 |
| ChemSpider | 362 |
| KEGG | C03248 |
| ChEBI | CHEBI:30781 |
| Jmol-3D images | Image 1 Image 2 |
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| Properties | |
| Molecular formula | C4H2O4 |
| Molar mass | 114.06 g mol−1 |
| Appearance | Crystalline solid |
| Melting point | |
| Hazards | |
| R-phrases | R25 R36/37/38 |
| S-phrases | S26 S45 |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Acetylenedicarboxylic acid or butynedioic acid is an organic compound (a dicarboxylic acid) with the formula C4H2O4 or HO2C-C≡C-CO2H. It is a crystalline solid that is soluble in diethyl ether.
The removal of two protons yields the acetylenedicarboxylate dianion C4O42−, which consists only of carbon and oxygen, making it an oxocarbon anion. Partial ionization yields the monovalent hydrogenacetylenedicarboxylate anion HC4O4−.
The acid was first described in 1877 by Polish chemist Ernest Bandrowski.[2][3][4] It can be obtained by treating α,β-dibromosuccinic acid with potassium hydroxide KOH in methanol or ethanol. The reaction yields potassium bromide and potassium acetylenedicarboxylate. The salts are separated and the latter is treated with sulfuric acid.[2]
Acetylenedicarboxylic acid is used in the synthesis of dimethyl acetylenedicarboxylate, an important laboratory reagent. Both the acid and the monobasic salt potassium hydrogenacetylenedicarboxylate KC4HO4 are commonly traded as laboratory chemicals.