Phenylarsonic acid
From Wikipedia, the free encyclopedia
| Phenylarsonic acid | |
|---|---|
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| IUPAC name | Phenylarsonic acid |
| Other names | Benzenearsonic acid PAA |
| Identifiers | |
| CAS number | [98-05-5] |
| Properties | |
| Molecular formula | C6H7AsO3 |
| Molar mass | 202.05 |
| Appearance | colourless solid |
| Density | 1.76 g/cm3 |
| Melting point |
154–158° °C |
| Solubility in water | low |
| Hazards | |
| Main hazards | Toxic |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Phenylarsonic acid is the chemical compound with the formula C6H5AsO(OH)2, commonly abbreviated PhAsO3H2. This colourless solid is an organic derivative of arsenic acid, AsO(OH)3, where one OH group has been replaced by a phenyl group. The compound is a buffering agent and a precursor to other organoarsenic compounds, some of which are used in animal nutrition, e.g. 4-hydroxy-3-nitrobenzenearsonic acid.
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[edit] Preparation and structure
PhAsO3H2 can be prepared in several routes, but a common one entails treatment of phenyl diazonium salts with sodium arsenite (prepared from arsenious acid and base) in the presence of a copper(II) catalyst.[1]
- C6H5N2+ + NaAsO3H2 → C6H5AsO3H2 + Na+ + N2
Related derivatives are prepared similarly.[2] It was first prepared by Michaelis and Loenser.[3][4][5] X-ray crystallography indicates that the molecules are connected by hydrogen-bonds consistent with short distance of 2.5 Å separating the oxygen atoms. The arsenic center is tetrahedral.[6]
[edit] Related phenylarsonic acids
Several derivatives of phenylarsonic acid have been used as additives for animal feeds. These include 4-hydroxy-3-nitrobenzenearsonic acid (3-NHPAA, or Roxarsone), p-arsanilic acid (p-ASA), 4-nitrophenylarsonic acid (4-NPAA), and p-ureidophenylarsonic acid (p-UPAA).
[edit] References
- ^ Bullard, R. H.; Dickey, J. B. “Phenylarsonic Acid” Organic Syntheses, Collected Volume 2, pages 494 (1943). http://www.orgsyn.org/orgsyn/pdfs/CV2P0494.pdf
- ^ Ruddy, A. W.; Starkey, E. B. “p-Nitrophenylarsonic Acid” Organic Syntheses, Collected Volume 3, pp. 665 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0665.pdf
- ^ A. Michaelis, H. Loesner (1877). "Ueber nitrirte Phenylarsenverbindungen". Berichte der deutschen chemischen Gesellschaft 27: 263–272. doi:.
- ^ A. Michaelis (1875). "Ueber aromatische Arsenverbindungen". Berichte der deutschen chemischen Gesellschaft 8: 1316–1317. doi:.
- ^ A. Michaelis, W. La Coste, A. Michaelis (1880). "Ueber die Verbindungen der Elemente der Stickstoffgruppe mit den Radicalen der aromatischen Reihe. Dritte Abhandlung: Ueber aromatische Arsenverbindungen". Annalen der Chemie 201 (2-3): 184–261. doi:.
- ^ Struchkov, Yu T. “Crystal and molecular structure of phenylarsonic acid” Russian Chemical Bulletin 1960, Volume 9, 1829-1833. doi:10.1007/BF00907739
