Dimethyl carbonate is briefly referred to as DMC. At room temperature, it is a colorless and transparent liquid with a pungent odor with a relative density (D204) of 1.0694, a melting point of 4 °C, boiling point of 90.3 °C, the flashpoint being 21.7 °C (opening) and being 16.7 °C (closed ) and the refractive index (nd20) being 1.3687. It is flammable and non-toxic and is miserable with almost all organic solvents in any proportion with alcohols, ketones, and esters. It is slightly soluble in water. It can be used as the methylating agent. Compared with other methylating reagents such as methyl iodide and dimethyl sulfate, dimethyl carbonate is less toxic, and biodegradable. The past method of making dimethyl carbonate with phosgene as raw materials are not frequently used. Instead, people now adopt the catalytic oxidative carbonylation of methanol in the presence of oxygen which is more environmentally friendly than the previous method. Dimethyl carbonate can enable methylation of aniline, phenol and carboxylic acid. However, many reactions demands high-pressure. DBU can be added during the reflux of DMC for catalyzing the methylation of carboxylic acid with dimethyl carbonate.
Application: Dimethyl carbonate product can be used as a traditional substitute for toxic materials phosgene, dimethyl sulfate and methyl chloride and so on. It can be used for synthesis of polycarbonate, diphenyl carbonate, isocyanate, and allyl diglycol carbonate ester; it can also be used for the synthesis of various kinds of carbamate pesticides such as carbaryl and so on; it can also be used as intermediate of organic synthesis such as anisole, dimethoxybenzene, alkylated aryl amines, symmetrical diamine urea, methyl carbazate and so on; in the pharmaceutical industry, it can be used for making amino oxazolidinone, ciprofloxacin, β- keto acid ester class pharmaceutical intermediates. In addition, it can be used as additives of gasoline, diesel fuel, the refrigerator oil, and solvent.