iodomethane

Iodomethane, also known as methyl iodide, is an organoiodine compound with the formula CH3I. It is a volatile methylating agent used widely in organic synthesis to introduce methyl groups into a variety of substrates. It is typically described as a colorless liquid or gas at room temperature, with a characteristic odor, and it readily hydrolyzes in water to give methanol and hydroiodic acid.

Industrial production of iodomethane generally involves the methylation of iodide sources using methanol under acidic conditions or the in situ generation of hydroiodic acid and reaction with methanol. It can also be prepared by iodination of alcohols with suitable iodinating reagents under controlled conditions. Because of its high reactivity, it is handled under strictly controlled conditions to avoid exposure and moisture.

In chemistry, iodomethane is valued for its strong electrophilic methyl group and its efficacy as an SN2 methylating agent. It reacts with a broad range of nucleophiles, including amines, thiols, and alkoxides, to form methylated products. This makes it a common reagent for converting primary and secondary amines to N-methyl or N,N-dimethyl derivatives, for forming methyl ethers, and for producing quaternary ammonium salts. It is a standard tool in pharmaceutical, agrochemical, and natural product synthesis where selective methylation is required.

Safety and handling: iodomethane is toxic and a potential occupational hazard. It is a volatile irritant that can affect the eyes, skin, and respiratory tract on exposure and hydrolyzes in moisture to methanol and hydroiodic acid. It should be stored tightly closed and kept away from moisture, with appropriate precautions to minimize inhalation and skin contact. Environmental controls are recommended to prevent release.