• Source: Diiodomethane

Diiodomethane or methylene iodide, commonly abbreviated "MI", is an organoiodine compound. Diiodomethane is a very dense colorless liquid; however, it decomposes upon exposure to light liberating iodine, which colours samples brownish. It is slightly soluble in water, but soluble in organic solvents. It has a very high refractive index of 1.741, and a surface tension of 0.0508 N·m−1.




Uses


Because of its high density, diiodomethane is used in the determination of the density of mineral and other solid samples. It can also be used as an optical contact liquid, in conjunction with the gemmological refractometer, for determining the refractive index of certain gemstones.
Diiodomethane is a reagent for installing the CH2 group. In the Simmons–Smith reaction, it is a source of methylene. In fact the Simmons–Smith reaction does not produce free carbene but proceeds via Zn-CH2I intermediates.
Diiodomethane is also a source of the equivalent of CH2+2. The synthesis of Fe2(CH2)(CO)8 illustrates this reactivity:

Na2Fe2(CO)8 + CH2I2 → Fe2(CH2)(CO)8 + 2 NaI




Preparation


Diiodomethane can be prepared from the widely available solvent dichloromethane by the action of sodium iodide in acetone in the Finkelstein reaction:

CH2Cl2 + 2 NaI → CH2I2 + 2 NaCl
It can also be prepared by reducing iodoform with elemental phosphorus or sodium arsenite:

CHI3 + Na3AsO3 + NaOH → CH2I2 + NaI + Na3AsO4




Safety


Alkyl iodides are alkylating agents, which are potential mutagens.




References






External links


Diiodomethane data sheet
New particle formation from photooxidation of diiodomethane Archived 2012-02-11 at the Wayback Machine

Kata Kunci Pencarian:

• Iodin
• Kamus rumus kimia
• Diiodomethane
• Amyl nitrite
• Norcarane
• Heavy liquid
• Sandmeyer reaction
• Dibromomethane
• Density
• Iodine dioxide
• Simmons–Smith reaction
• Iodoform