Dimethyl carbonate
| Dimethyl carbonate | |
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Dimethyl carbonate |
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Other names
DMC |
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| Identifiers | |
| CAS number | 616-38-6  |
| PubChem | 12021 |
| ChemSpider | 11526 |
| ChEBI | CHEBI:36596 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C3H6O3 |
| Molar mass | 90.08 g mol−1 |
| Appearance | Clear liquid |
| Density | 1.069-1.073 g/mL |
| Melting point |
2-4 °C, 275-277 K, 36-39 °F |
| Boiling point |
90 °C, 363 K, 194 °F |
| Solubility in water | 13.9 g/100 mL |
| Hazards | |
| Main hazards | Flammable |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Dimethyl carbonate (DMC) is an organic compound with the formula OC(OCH3)2. It is a colourless, flammable liquid. It is classified as a carbonate ester. This compound has found use as a methylating agent and more recently as a solvent that is exempt from classification as a Volatile organic compound (VOC) in the US. Dimethyl carbonate is often considered to be a green reagent.[1]
Contents |
[edit] Production
Dimethyl carbonate can be prepared by the reaction of phosgene with methanol via methyl chloroformate:
- COCl2 + CH3OH → CH3OCOCl + HCl
- CH3OCOCl + CH3OH → CH3OCO2CH3 + HCl
Overall:
- COCl2 + 2 CH3OH → CH3OCO2CH3 + 2 HCl
This historical synthesis process is undesirable because of phosgene's toxicity and has been largely replaced by other synthesis routes. It is produced industrially by a transesterification of propylene carbonate and methanol, which also affords propylene glycol. A second large scale commercial synthesis route uses a process where carbon monoxide, methanol and oxygen are reacted to form dimethyl carbonate.[2] World production in 1997 was estimated at 1000 barrels a day.[3] Production of dimethyl carbonate worldwide is limited to Asia and Europe.
[edit] Reactions and potential applications
[edit] Methylating agent
Dimethyl carbonate methylates anilines, phenols and carboxylic acids, but many of these reactions require the use of an autoclave.[4][5] and the preparation of methyl carboxylate esters:[4]
Dimethyl carbonate's main benefit over other methylating reagents such as iodomethane and dimethyl sulfate is its much lower toxicity and its biodegradability.[2] Unfortunately, it is a relatively weak methylating agent compared to these traditional reagents.
[edit] Solvent
In the US, DMC was exempted under the definition of volatile organic compounds by the U.S. EPA in 2009.[6] Due to its classification as a "green solvent", dimethyl carbonate has grown in popularity and applications as a replacement for methyl ethyl ketone, tert-butyl acetate, and parachlorobenzotrifluoride.
[edit] Alternative fuel additive
There is also interest in using this compound as a fuel oxygenate additive.[3]
[edit] References
- ^ Kreutzberger, Charles B. (2001), "Chloroformates and Carbonates", Kirk-Othmer Encyclopedia of Chemical Technology, New York: John Wiley, doi:10.1002/0471238961.0301180204011312.a01.pub2
- ^ a b Pietro Tundo and Maurizio Selva (2002). "The Chemistry of Dimethyl Carbonate". Acc. Chem. Res. 35 (9): 706–16. doi:10.1021/ar010076f.
- ^ a b Pacheco, Michael A.; Marshall, Christopher L. (1997). "Review of Dimethyl Carbonate (DMC) Manufacture and Its Characteristics as a Fuel Additive". Energy Fuels 11: 2–29. doi:10.1021/ef9600974.
- ^ a b Shieh, Wen-Chung; Dell, Stephen; Repič, Oljan (2002). "Nucleophilic Catalysis with 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) for the Esterification of Carboxylic Acids with Dimethyl Carbonate". J. Org. Chem. 67 (7): 2188–2191. doi:10.1021/jo011036s.
- ^ Shieh, Wen-Chung; Dell, Steven; Repič, Oljan (2001). "1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) and Microwave-Accelerated Green Chemistry in Methylation of Phenols, Indoles, and Benzimidazoles with Dimethyl Carbonate". Organic Letters 3 (26): 4279–81. doi:10.1021/ol016949n. PMID 11784197.
- ^ http://www.epa.gov/ttncaaa1/t1/fact_sheets/voc_exemp01011309.pdf. Information about the EPA's action on exempting dimethyl carbonate as a VOC and petitioner's background information, public comments and other references are available electronically at http://www.regulations.gov, EPA’s electronic public docket and comment system. The docket number for this action is Docket ID No. EPA-HQ-OAR-2006-0948. See http://www.epa.gov/ttn/oarpg/t1pfpr.html and scroll down to Jan 13, 2009 pdf for the rule.
