Hydroiodic acid
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Names | |||
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IUPAC name
Iodane[1]
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Other names
Hydronium iodide
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Identifiers | |||
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Properties | |||
HI(aq) | |||
Molar mass | 127.91 g/mol | ||
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 | |||
GHS labelling: | |||
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Signal word
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Danger | ||
H314 | |||
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501 | |||
NFPA 704 (fire diamond) | ![]()
3
0
0 ACID | ||
Flash point | Non-flammable | ||
Related compounds | |||
Other anions
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Hydrofluoric acid Hydrochloric acid Hydrobromic acid | ||
Related compounds
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Hydrogen iodide | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Infobox references | |||
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% to 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]
![The catalytic cycle of the Cativa process](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Cativa-process-catalytic-cycle.png/400px-Cativa-process-catalytic-cycle.png)
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)
External links[]
- Iodides
- Acids
- Nonmetal halides
- Reducing agents