Ethyl iodide (also iodoethane) is a colorless

flammable A combustible material is a material that can burn (i.e., sustain a flame) in air under certain conditions. A material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort ...

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

. It has the chemical formula C₂H₅I and is prepared by heating

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

with

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

and

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

.''Merck Index of Chemicals and Drugs'', 9th ed., monograph 3753 On contact with air, especially on the effect of light, it decomposes and turns yellow or reddish from dissolved iodine. It may also be prepared by the reaction between

hydroiodic acid Hydroiodic acid (or hydriodic acid) is a colorless liquid. It is an aqueous solution of hydrogen iodide with the chemical formula . It is a strong acid, in which hydrogen iodide is ionized completely in an aqueous solution. Concentrated aqueous ...

and ethanol, typically by generating the hydroiodic acid ''in situ'' via an iodide salt (such as sodium iodide) and an acid (such as sulfuric acid), after which the ethyl iodide is distilled off. Ethyl iodide should be stored in the presence of copper powder to avoid rapid decomposition, though even with this method samples do not last more than 1 year. Ethyl Iodide production

Because iodide is a good

leaving group In organic chemistry, a leaving group typically means a Chemical species, molecular fragment that departs with an electron, electron pair during a reaction step with heterolysis (chemistry), heterolytic bond cleavage. In this usage, a ''leaving gr ...

, ethyl iodide is an excellent ethylating agent. It is also used as the hydrogen radical promoter.

Production

Ethyl iodide is prepared by using red

, absolute

and

. The iodine dissolves in the ethanol, where it reacts with the solid phosphorus to form

phosphorus triiodide Phosphorus triiodide (PI3) is an inorganic compound with the formula PI3. A red solid, it is too unstable to be stored for long periods of time; it is, nevertheless, commercially available. It is widely used in organic chemistry for converting alco ...

. During this process, the temperature is controlled. :3 C₂H₅OH + PI₃ → 3 C₂H₅I + H₃PO₃ The crude product is purified by distillation.

References

{{Authority control Iodoalkanes Ethylating agents Organoiodides