Dimethyl carbonate
Dimethyl carbonate is a fast, VOC-exempt solvent in the US, used to cut the regulated VOC content of solventborne coatings, inks and adhesives.
DMC is the dimethyl ester of carbonic acid (molecular weight 90.08 g/mol). It is a clear, colorless liquid with a mild, pleasant odor that boils at about 90 °C, has a flash point of about 17 °C and freezes at about 2–4 °C.
The US EPA exempted DMC from the federal VOC definition in 2009 because of its negligible photochemical reactivity. Formulators use it to replace part of the toluene, MEK, acetone or esters in solventborne coatings, inks and adhesives to meet VOC limits. Outside coatings, DMC is used in lithium-ion battery electrolytes and as a methylating and carbonylating reagent.
DMC is highly flammable and needs the same fire precautions as acetone or toluene: ventilation, grounding and bonding, and no ignition sources. Its toxicity is comparatively low, but follow the SDS. Store above its freezing point. Being VOC-exempt does not make it non-flammable or non-hazardous.
The US EPA does not count the solvent toward federal VOC limits because it contributes very little to ground-level ozone formation. Some states, air districts and other countries have their own rules, so check the regulations that apply.
It freezes at about 2–4 °C. Store it in heated space in winter, and warm and mix it before use if it solidifies.
It has a more favorable toxicity profile than toluene, but it is just as flammable. Fire precautions are the same.
