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| Names | |||
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| IUPAC name Iodane[1] | |||
| Other names Hydronium iodide | |||
| Identifiers | |||
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| Properties | |||
Chemical formula | HI(aq) | ||
| Molar mass | 127.91 | ||
| Appearance | colorless liquid | ||
| Odor | acrid | ||
| Density | 1.70 g/mL, azeotrope (57% HI by weight) | ||
| Boiling point | 127 °C (261 °F; 400 K) 1.03 bar, azeotrope | ||
| Aqueous solution | |||
| Acidity (pKa) | -9.3 | ||
| Hazards | |||
EU classification (DSD) (outdated) | Corrosive (C) | ||
| R-phrases (outdated) | R34 | ||
| S-phrases (outdated) | (S1/2), S26, S45 | ||
| NFPA 704 (fire diamond) | |||
| Flash point | Non-flammable | ||
| Related compounds | |||
Other anions | Hydrofluoric acid Hydrochloric acid Hydrobromic acid | ||
Related compounds | Hydrogen iodide | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
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Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, , one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48 - 57% HI.[2]
Reactions
Hydroiodic acid reacts with oxygen in air to give iodine:
- 4 HI + O2 → 2 H
2O + 2 I2
Like other hydrogen halides, hydroiodic acid adds to alkenes to give alkyl iodides. It can also be used as a reducing agent, for example in the reduction of aromatic nitro compounds to anilines.[3]
Cativa process
The Cativa process is a major end use of hydroiodic acid, which serves as a co-catalyst for the production of acetic acid by the carbonylation of methanol.[4][5]
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Illicit uses
Hydroiodic acid is listed as a U.S. Federal DEA List I Chemical, owing to its use as a reducing agent related to the production of methamphetamine from ephedrine or pseudoephedrine (recovered from nasal decongestant pills).[6]
References
- ^ Henri A. Favre; Warren H. Powell, eds. (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. Cambridge: The Royal Society of Chemistry. p. 131.
- ^ Lyday, Phyllis A. (2005). "Iodine and Iodine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. pp. 382–390. doi:10.1002/14356007.a14_381.
- ^ Kumar, J. S. Dileep; Ho, ManKit M.; Toyokuni, Tatsushi (2001). "Simple and chemoselective reduction of aromatic nitro compounds to aromatic amines: reduction with hydriodic acid revisited". Tetrahedron Letters. 42 (33): 5601–5603. doi:10.1016/s0040-4039(01)01083-8.
- ^ Jones, J. H. (2000). "The Cativa Process for the Manufacture of Acetic Acid" (PDF). Platinum Metals Rev. 44 (3): 94–105.
- ^ Sunley, G. J.; Watson, D. J. (2000). "High productivity methanol carbonylation catalysis using iridium - The Cativa process for the manufacture of acetic acid". Catalysis Today. 58 (4): 293–307. doi:10.1016/S0920-5861(00)00263-7.
- ^ Skinner, Harry F. "Methamphetamine Synthesis via HI/Red Phosphorus Reduction of Ephedrine". Forensic Science International, 48 128-134 (1990)