Dimethyl dicarbonate
- Dimethylpyrocarbonate
- Pyrokohlensäuredimethylester
- E 242
Colorless, clear liquid of fruity- ester type odor
Liquid
1.25 g · cm -3
17 ° C
172 ° C ( decomposition)
Poorly in water ( ~ 35 g · l-1 at 20 ° C) with decomposition
Risk
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Dimethyl dicarbonate ( DMDC ) and dimethyl pyrocarbonate ( DMPC), is an ester of the pyrocarbonate.
Use
Is dimethyl dicarbonate as a food additive under the number E 242 as declarable free cold disinfectants. It is an alkylating agent and kills pests, such as typical beverage fermentation yeasts by alkylation ( methylation in this case ), of DNA and proteins from.
According to the additive approval regulations for non-alcoholic flavored drinks and wine, dimethyl dicarbonate is approved according to § 5 for non-alcoholic wine and Liquid-. A maximum of 250 mg per liter are added. According to EC Regulation Regulation (EC ) 606 /2009 ( EU ÖnologiekodexVO ) Annex IA No. 34 Dimethyldicarbonate is approved for direct human consumption in certain grape, table wine, sparkling wine, semi-sparkling wine, liqueur wines and quality wines. It may be added to a maximum of 200 mg per liter, and in the finished product no Dimethyldicarbonate must be detectable more. A previously prescribed residual sugar content of the wine of> 5 g / l, according to the latest regulation are no longer necessary (EC ) No 315 /2012. Dimethyldicarbonate may therefore also be used for dry wines.
The addition must be done with a dispenser. A simple stirring brings a drop in the tank and therefore no effect. It is marketed under the trade name Velcorin ® from Lanxess AG.
Compatibility
After addition to the beverage Dimethyldicarbonate decomposes a function of temperature in about 4 hours in methanol and carbon dioxide, natural components of many beverages such as fruit and vegetable juices, and is no longer available when purchasing. The resulting small amounts of methanol is toxicologically evaluate as safe.
Depending on the ingredients, ie in the presence of ammonium ions ( NH4 ) and aqueous- acid solution, but the smallest amounts of O -methyl- carbamate (O- methylurethan ) may form. This connection is toxicologically well studied and it has been shown that it causes cancer in rats. O -methyl- carbamate was detected in wines that were disinfected with dimethyl dicarbonate. It can be found on the list of cancer-causing substances in the State of California.
By 1973, diethyl dicarbonate was used instead of dimethyl dicarbonate. This forms under the same conditions O -ethyl- carbamate ( ethyl urethane ) which is greater toxicological concern than O -methyl- carbamate. For this reason, the addition of diethyl dicarbonate was banned in 1973 and drinks Dimethyldicarbonate used as a result of active ingredient.
O -methyl- carbamate is sometimes incorrectly placed in connection with carbamates of the plant protection. Carbamates from the plant protection products are used as insecticides, fungicides and herbicides, and are chemically more complex structured N-alkyl- carbamates. The greatest likelihood of confusion with the class of fungicidal N- methyl carbamates, because N and O are often omitted and thus faking an identity.
Asthmatics should not stay in rooms where work with dimethyl dicarbonate as the substance can trigger asthma attacks.
Disintegration time of dimethyl
- At 10 ° C → about 5 hours
- At 20 ° C for about 2 hours →
- At 30 ° C, 1 hour →
The pH increases only slightly affect the decay, decisive is the temperature.
Reaction products of DMDC with ingredients in the beverage
- Alcohol content> 1 % by volume:
→ carbon dioxide methanol methyl ethyl
- Ammonia, amines, amino acids, phenols:
→ carbon dioxide methanol methyl carbamate