Dimethyl dicarbonate

Dimethyl dicarbonate
IUPAC name methoxycarbonyl methyl carbonate
Other names DMDC dicarbonic acid dimethyl ester dimethyl pyrocarbonate Velcorin
Identifiers
CAS number	4525-33-1 Y
PubChem	3086
ChemSpider	2976 Y
Jmol-3D images	Image 1 Image 2
SMILES O=C(OC(=O)OC)OC O=C(OC)OC(=O)OC
InChI InChI=1S/C4H6O5/c1-7-3(5)9-4(6)8-2/h1-2H3 Y Key: GZDFHIJNHHMENY-UHFFFAOYSA-N Y InChI=1/C4H6O5/c1-7-3(5)9-4(6)8-2/h1-2H3 Key: GZDFHIJNHHMENY-UHFFFAOYAQ
Properties
Molecular formula	C4H6O5
Molar mass	134.09 g mol−1
Appearance	Colourless liquid
Density	1.25 g/ml (liquid)
Melting point	16-18 °C, 289-291 K, 61-64 °F
Boiling point	172 °C, 445 K, 342 °F
Viscosity	2.1 Pa·s (20 °C)
Hazards
R-phrases	R22 R23 R34
S-phrases	S7/9 S26 S36/37/39 S45
Main hazards	Toxic
Y dicarbonate (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Dimethyl dicarbonate or DMDC is a colourless liquid with a sharp odour. Its primary use is as a beverage preservative and or processing aid or sterilant (INS No. 242), and acts by inhibiting the enzymes acetate kinase and L-glutamic acid decarboxylase.^[1] 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.^[2] Once it has been added to beverages, the efficacy of the chemical is provided by the following reactions:

• DMDC + H₂O → 2CH₃OH + 2CO₂
• DMDC + EtOH → Ethyl methyl carbonate
• DMDC + NH₃ → 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 FDA approved its use in wines in 1988, with the maximum permitted level being set at 200 mg/L, and only if there were fewer than 500 yeast cells/mL at time of dosage. It is listed as approved in the EU^[3] (where it is listed under E number E242) and USA^[4] but is not listed in Australia and New Zealand.^[5] The application of DMDC is particularly useful when wine needs to be sterilised but cannot be sterile filtered, pasteurized, or sulfured.

DMDC is used to stabilise non alcoholic beverages such as carbonated or non carbonated juice beverages, isotonic sports beverages, iced teas and flavoured waters.

DMDC is added before the filling of the beverage. It then breaks down into small amounts of methanol and carbon dioxide, which are both natural constituents of fruit and vegetable juices.

The EU Scientific Committee on food, the FDA in the United States and the JECFA of the WHO have confirmed the safe use in beverages.

References

1. ^ [1]^{[dead link]}
2. ^ DMDC's role in bottle stability - dimethyl dicarbonate, Wines & Vines, Oct 1990
3. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist. Retrieved 2011-10-27. 
4. ^ US Food and Drug Administration: "Listing of Food Additives Status Part I". http://www.fda.gov/Food/FoodIngredientsPackaging/FoodAdditives/FoodAdditiveListings/ucm091048.htm. Retrieved 2011-10-27. 
5. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". http://www.comlaw.gov.au/Details/F2011C00827. Retrieved 2011-10-27. 

External links

• Dimethyl dicarbonate at EPA SRS
• Dimethyl dicarbonate technical data at FAO
• Dimethyl dicarbonate and microbiological stability