View source for Dimethyl dicarbonate

{{Chembox/Top|Dimethyl dicarbonate}}
{{Chembox/Image|Dimethyl dicarbonate.png|Dimethyl dicarbonate}}
{{Chembox/SectGeneral}}
{{Chembox/IUPACName|methoxycarbonyl methyl carbonate}}
{{Chembox/OtherNames|DMDC<br>dicarbonic acid<br>dimethyl ester<br>dimethyl pyrocarbonate<br>Velcorin®}}
{{Chembox/Formula|C<sub>4</sub>H<sub>6</sub>O<sub>5</sub>}}
{{Chembox/SMILES|<nowiki>O=C(OC(=O)OC)OC</nowiki>}}
{{Chembox/MolarMass|134.09}}
{{Chembox/Appearance|Colourless liquid}}
{{Chembox/CASNo|4525-33-1}}
{{Chembox/SectProperties}}
{{Chembox/Density|1.25|g/ml|liquid}}
{{Chembox/SolubilityWater|3.4|20}} <!-- for numerical values in g/100g at a given temperature -->
<!-- {{Chembox/Solubility|solvent|?}} for other solvents and non-numerical values e.g. ''decomposes'' -->
{{Chembox/MeltingPt|16-18°C}} <!-- include unit, mention any decomposition -->
{{Chembox/BoilingPt|172°C}} <!-- include unit, mention any decomposition -->
{{Chembox/Viscosity|2.1 [[Pascal second|Pa.s]]|20}} <!-- Liquids only, omit if data unavailable. You may use [[Pascal second|Pa.s]] if you prefer -->
{{Chembox/SectHazards}} <!--  Summary only, MSDS provides more complete information -->
{{Chembox/MainHazards|Toxic}} <!-- e.g. highly toxic, explosive, flammable, corrosive -->
<!-- {{Chembox/EUClass|?}} alternative to the above section -->
<!-- {{Chembox/NFPA|4|4 ox|4}} These are set on "very dangerous" as default- adjust according to actual values -->
{{Chembox/RPhrases|22-23-34}}
|[[List of S-phrases|S-phrases]]
|{{S7/9}}, {{S26}}, {{S36/37/39}}, {{S45}}
|-
<!-- {{Chembox/SPhrases|{{S7/9}}, {{S26}}, {{S36/37/39}}, {{S45}}}}-->
<!-- {{Chembox/RSPhrases|?|?}} alternative to the two previous sections -->
{{Chembox/FlashPt|85°C}}
<!-- {{Chembox/RTECSNo|?}} RTECS number, optional -->
{{Chembox/Bottom}}

'''Dimethyl dicarbonate''' or '''DMDC''' is a colourless liquid with a sharp odour. Its primary use is as a [[drink|beverage]] [[preservative]] or [[Sterilization (microbiology)#Chemical sterilization|sterilant]] ([[International Numbering System|INS No.]] 242), and acts by [[Enzyme inhibitor|inhibiting]] the [[enzyme]]s [[acetate kinase]] and [[L-glutamic acid decarboxylase]] [http://chembank.broad.harvard.edu/compounds/display_structure.html?tab=properties&structure_id=1924]. It has also been proposed that methoxycarbonylation of the [[histidine]] part of the enzymes [[alcohol dehydrogenase]] and [[glyceraldehyde 3-phosphate dehydrogenase]] by DMDC inhibits these essential enzymes also [http://www.findarticles.com/p/articles/mi_m3488/is_n10_v71/ai_8963440]. Once it has been added to beverages, the efficacy of the chemical is provided by the following reactions:

*DMDC + H<sub>2</sub>O → 2CH<sub>3</sub>OH + 2CO<sub>2</sub>
*DMDC + ROH → Ethyl methyl carbonate
*DMDC + NH<sub>3</sub> → Methyl carbamate
*DMDC + [[Amino acid]] → Derived carboxymethyl

DMDC is sometimes used as a preservative in [[wine]] as a replacement to [[sulfur dioxide]], inactivating wine spoilage yeasts such as [[Brettanomyces]]. In the U.S. the [[Food and Drug Administration|FDA]] approved its use in wines in 1998, with the maximum permitted level being set at 200mg/L, and only if there was less than 500 yeast cells/mL at time of dosage. Usage has also been approved in [[Germany]] (since 1978) and [[New Zealand]]. The application of DMDC is particularly useful when wine needs to be sterilised but cannot be sterile filtered, [[pasteurization|pasteurized]], or sulfured.

DMDC has also been used to sterilise [[coffee]], [[tea]], [[cider]], [[fruit wine]] and [[mead]].

==External links==
*[http://oaspub.epa.gov/srs/srs_proc_qry.navigate?P_SUB_ID=125658 Dimethyl dicarbonate at EPA SRS]
*[http://www.panreac.es/new/ing/catalogo/fichastec/205802IN.HTM Dimethyl dicarbonate technical data at Panreac]
*[http://apps3.fao.org/jecfa/additive_specs/docs/0/additive-0155.htm Dimethyl dicarbonate technical data at FAO]
*[http://www.findarticles.com/p/articles/mi_m3488/is_n10_v71/ai_8963440 Dimethyl dicarbonate and microbiological stability]

[[Category:Oenology]]
[[Category:Preservatives]]

[[de:Dimethyldicarbonat]]
[[nl:Dimethyldicarbonaat]]