Dimethyl carbonate

• DMC
• Methyl carbonate
• Dimethyl

Colorless liquid with a pleasant odor

Liquid

1.07 g · cm -3 ( 20 ° C)

0.5 to 4.7 ° C

90 ° C ( 1,016 hPa)

53 hPa ( 20 ° C)

139 g · l-1 (20 ° C ) in water

1.3687 (20 ° C)

Risk

9000 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

Dimethyl carbonate or dimethyl carbonate is an organic chemical compound which can be seen as dimethyl esters of carbonic acid.

Representation and extraction

Dimethyl carbonate can be produced in a two-phase reaction by reacting methanol with phosgene or methyl chloroformate in a concentrated sodium hydroxide solution. A more modern synthesis proceeds as direct oxidative carbonylation of methanol, by means of carbon monoxide and oxygen in the presence of copper catalysts.

Properties

Dimethyl carbonate is a flammable, colorless liquid. At atmospheric pressure, the compound boils at 90 ° C. The vapor pressure function is given by Antoine corresponding log10 (P) = A- ( B / ( T C)) (P in kPa, T in K) with A = 11.7067, B = 2158.837 and C = -153.531 in temperature range of 310 K to 364 K. The critical point is reached at a temperature Tc = 284 ° C and a pressure of Pc = 48 bar having a critical density of 3.97 mol.l -1. It has a flash point of 14 ° C and an ignition temperature of 458 ° C. Between 4.22 and 12.87 % by volume, it forms explosive mixtures with air.

Use

In a mixture with ethylene carbonate, the compound is used in nonaqueous electrolyte solutions for lithium batteries. In the organic synthesis of dimethyl carbonate is used as a methylating agent. In addition, it is increasingly replacing the highly toxic phosgene in the manufacture of polycarbonate resins.