Dimethyl carbonate-

Dimethyl carbonate, abbreviated as DMC, is a colorless, transparent liquid with a pungent odor at room temperature. Its relative density (d204) is 1.0694, melting point is 4°C, boiling point is 90.3°C, flash point is 21.7°C (open cup) and 16.7°C (closed cup), refractive index (nd20) is 1.3687. It is combustible and non-toxic. It is miscible in any proportion with almost all organic solvents such as alcohols, ketones, and esters, and slightly soluble in water. It can serve as a methylating agent. Compared to other methylating agents like methyl iodide and dimethyl sulfate, dimethyl carbonate exhibits lower toxicity and is biodegradable. The former method of producing dimethyl carbonate from phosgene is now uncommon, replaced by catalytic oxidation carbonylation of methanol in oxygen—a more environmentally friendly approach. Dimethyl carbonate can methylate aniline, phenol, and carboxylic acids, though many reactions require high pressure. DBU can be added during refluxing DMC to catalyze the methylation of carboxylic acids by dimethyl carbonate:

Dimethyl carbonate (DMC) possesses a unique molecular structure (CH₃O-CO-OCH₃), containing a carbonyl group, methyl group, methoxy group, and carbonyl methoxy group. This structure enables its extensive application in organic synthesis reactions such as carbonylation, methylation, methoxylation, and carbonyl methoxylation. It serves a wide range of purposes, primarily as a carbonylation and methylation reagent, gasoline additive, and raw material for synthesizing polycarbonate (PC). Large-scale DMC production developed alongside the non-phosgene synthesis process for polycarbonate. Its applications include: 1. A novel low-toxicity solvent that can replace toluene, xylene, ethyl acetate, butyl acetate, acetone, or methyl ethyl ketone in the paint and adhesive industries, serving as an environmentally friendly green chemical product. 2. An effective methylating agent, carbonylating agent, hydroxymethylating agent, and methoxylating agent, widely used in food antioxidants, plant protection agents, and other fields as a versatile chemical raw material. 3. An ideal substitute for highly toxic chemicals like phosgene, dimethyl sulfate, and methyl chloroformate. 4. Used in synthesizing polycarbonates, diphenyl carbonate, isocyanates, and other compounds. 5. In pharmaceuticals, used for synthesizing anti-infective drugs, antipyretic analgesics, vitamin preparations, and central nervous system medications. 6. In pesticides, primarily used to produce methyl isocyanate, which is further processed into certain carbamate pesticides and insecticides (benzylamine). 7. Used in gasoline additives and lithium battery electrolytes.