- Diiodomethane
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Diiodomethane 
DiiodomethaneOther namesMethylene iodide, Methylene diiodide, Methyl diiodideIdentifiers CAS number 75-11-6 
PubChem 6346 ChemSpider 6106 EC number 200-841-5 RTECS number PA8575000 Jmol-3D images Image 1 - ICI
- InChI=1S/CH2I2/c2-1-3/h1H2
Key: NZZFYRREKKOMAT-UHFFFAOYSA-N
InChI=1/CH2I2/c2-1-3/h1H2
Key: NZZFYRREKKOMAT-UHFFFAOYAO
Properties Molecular formula CH2I2 Molar mass 267.84 g/mol Appearance Colorless liquid with chloroform-like odour Density 3.325 g/cm3 Melting point 6 °C, 279 K, 43 °F
Boiling point 181 °C (358 °F) (decomp.)
Solubility in water 14 g/l at 20 °C Hazards MSDS MSDS at the University of Oxford, J.T.Baker MSDS EU classification Harmful (Xn) R-phrases R20/22 S-phrases S26, S27, S36/37/39 NFPA 704 
130Flash point 113 °C 
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)Infobox references Diiodomethane or methylene iodide, commonly abbreviated "MI", is a liquid organoiodine compound. It is insoluble in water, but soluble in ether and alcohol. It has a relatively high refractive index of 1.741, and a surface tension of 0.0508 N·m−1.[1] Diiodomethane is a colorless liquid, however, it decomposes upon exposure to light liberating iodine, which colours samples brownish.
With its high specific gravity, diiodomethane is used in the determination of the density of mineral and other solid samples. It is also used as a contact liquid for refractometers. Diiodomethane is a reagent in the Simmons-Smith reaction, serving as a source of methylene CH2.[2]
Contents
Preparation
Although commercially available, it can be prepared by reducing iodoform with sodium arsenite:[3]
- CHI3 + Na3AsO3 + NaOH → CH2I2 + NaI + Na3AsO4
Diiodomethane can also be prepared from dichloromethane by the action of sodium iodide in acetone in the Finkelstein reaction:[3]
- CH2Cl2 + 2 NaI → CH2I2 + 2 NaCl
Safety
Alkyl iodides are alkylating agents and contact should be avoided.
References
- ^ Website of Krüss (8.10.2009)
- ^ Two cyclopropanation reactions: Smith, R. D.; Simmons, H. E., "Norcarane", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv5p0855; Coll. Vol. 5: 855, Ito, Y.; Fujii, S.; Nakatuska, M.; Kawamoto, F.; Saegusa, T. (1988), "One-Carbon Ring Expansion Of Cycloalkanones To Conjugated Cycloalkenones: 2-Cyclohepten-1-one", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0327; Coll. Vol. 6: 327
- ^ a b Roger Adams, C. S. Marvel (1941), "Methylene Iodide", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0358; Coll. Vol. 1: 358
External links
Halomethanes Monosubstituted Disubstituted Trisubstituted Categories:- Organoiodides
- Halomethanes
- Halogenated solvents
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