Violuric acid
 Sample prepared by SM-user RustyShackleford
| |
| Names | |
|---|---|
| IUPAC name
6-Hydroxy-5-nitroso-1H-pyrimidine-2,4-dione
| |
| Other names
2,4,5,6(1H,3H)-Pyrimidinetetrone 5-oxime
5-Hydroxyiminobarbituric acid 5-Isonitrosobarbituric acid Alloxan 5-oxime | |
| Properties | |
| C4H3N3O4 (anhydrous) C4H3N3O4·H2O (monohydrate) | |
| Molar mass | 157.08 g/mol (anhydrous) 175.10 g/mol (monohydrate) |
| Appearance | Off-white yellow or yellow cream solid |
| Odor | Odorless |
| Melting point | 247 °C (477 °F; 520 K) (decomposes) |
| Boiling point | Decomposes |
| 0.704 g/100 ml (20 °C)[1] | |
| Solubility | Soluble in alcohols |
| Vapor pressure | ~0 mmHg |
| Acidity (pKa) | 4.7 |
| Hazards | |
| Safety data sheet | Sigma-Aldrich (monohydrate) |
| Related compounds | |
| Related compounds
|
Barbituric acid |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Violuric acid is an organic chemical compound, used to prepare various colored salts. It was discovered in 1863/64 by Adolf Baeyer.[2]
Contents
Properties
Chemical
Violuric acid reacts with metals to form brightly colored violurate salts. Even touching the free acid with a metal spatula may cause the formation of violurate salts.
Violuric acid tautomerizes in water from the isonitroso- form to the violet nitroso- form.
Physical
Violuric acid is a yellowish solid, poorly soluble in water.
Availability
Violuric acid is sold by chemical suppliers.
Preparation
Violuric acid can be prepared by acidifying sodium violurate with hydrochloric acid. Sodium violurate can be prepared by adding barbituric acid to a hot aq. solution of sodium nitrite and stir. The sodium salt can be precipitated out of the solution by adding NaCl.[3]
Can also be prepared from from hydroxylamine and alloxan.[4]
Projects
- Make brightly colored salts
Handling
Safety
There is little data available for its toxicity and environmental effects.
Storage
In closed plastic or glass bottles.
Disposal
No special disposal is required.
References
- ↑ https://echa.europa.eu/registration-dossier/-/registered-dossier/26979/4/9
- ↑ Baeyer, A. (1863), Untersuchungen über die Harnsäuregruppe. Justus Liebigs Ann. Chem., 127: 199-236. https://doi.org/10.1002/jlac.18631270214
- ↑ German thread on violuric acid, https://illumina-chemie.de/viewtopic.php?f=69&t=5502
- ↑ Guinchard, J. (1899), Ueber die farbigen Salze aus Violursäure und anderen ringförmigen Oximidoketonen. Ber. Dtsch. Chem. Ges., 32: 1723-1741. https://doi.org/10.1002/cber.18990320260
