This file is a part of the Rhodium site archive. This Aug 2004 static snapshot is hosted by Erowid
as of May 2005 and is not being updated. > > Back to Rhodium Archive Index > >

Synthesis of Methyl Iodide

[ Back to the Chemistry Archive ]


Methyl Iodide is an important reagent in organic chemistry. It affords the organic chemist a means of adding a methyl group to compounds. It is most conveniently prepared by the reaction of PI3 on methanol.

Dissolve 83.8 grams (2/3 mole.) of Iodine in 120 ml. of methanol. Pour into 250 ml sep. funnel attach to rb. flask. Add 42.3 grams (1/3 mole) red Phosphorus to flask and swirl. Depending on ambient conditions heat may be required to start the reaction. If heat is used be prepared to remove and cool if needed to maintain slow but steady distillation. Once initial reaction has stabilized add more iodine/methanol solution dropwise to maintain a slow and steady distillation. Collect the fraction boiling at 42C. When the reaction has subsided, do not heat flask excessively as Phosphine may be produced

Notes: Maintain cold water through condenser at all times ensure all joints are tight and vapour secure keep receiver flask submerged and well chilled. Yield 50-60 ml, or 80-90%