User:Rifleman 82/sandbox

Dimethyl carbonate, often abbreviated DMC, a carbonate ester, is a flammable clear liquid boiling at 90 °C. This compound has found use as a methylating agent. There is also interest in using this compound as a fuel oxygenate additive, and as a solvent. It was classified as an exempt compound under the definition of volatile organic compounds by the U.S. EPA in 2009.

Production
Dimethyl carbonate may be prepared by reaction of phosgene with methanol via methyl chloroformate:


 * COCl2 + CH3OH &rarr; CH3OCOCl + HCl
 * CH3OCOCl + CH3OH &rarr; CH3OCO2CH3 + HCl

Overall:
 * COCl2 + 2 CH3OH &rarr; CH3OCO2CH3 + 2 HCl

This process is undesirable because of phosgene's toxicity. Many other routes have been found, and some of them have been commercialized. World production in 1997 was estimated at 1000 barrels a day.

Reactions
Dimethyl carbonate's main benefit over other methylating reagents such as iodomethane and dimethyl sulfate is its much lower toxicity and its biodegradability. Also, it is now prepared from catalytic oxidative carbonylation of methanol with carbon monoxide and oxygen, instead of from phosgene. This allows dimethyl carbonate to be considered a green reagent.

Dimethyl carbonate is able to methylate anilines, phenols and carboxylic acids, but many of these reactions require the use of an autoclave. One alternative involves the use of DBU, which allows methylation of phenols, indoles, and benzimidazoles and the preparation of methyl carboxylate esters:


 * [[Image:DMC Methylation.png|350px|Methylation of phenylacetic acid by dimethyl carbonate promoted by DBU]]