??? ????? C??? ??, ??, ??
??
??? ???? ??? ? ?????. ??? ?? ????? ???, ??? ? ?? ?? ??? ?????.
??
??? ?????? DMC? ???? ???? ?? ??? ??? ?????. ?? ?? (d204)? 1.0694, ??? 4 ℃, ???? 90.3 ℃, ???? 21.7 ℃ (??) 16.7 ℃ (??)), ??? (nd20) 1.3687 , ???, ? ??.
??
DMC? ?? ??? ?????. ???, ??, ????? ?? ?? ??? ?? ? ? ??? ?? ?? ?????. ??? ????, ?? ? ?? ?, ?? ??? ? ?? ??? ??? ?? ?? ? ??? ?????. ??? ?? ???? ??? ??? ??? ? ????. ?? ? ????? DMC? ciprofloxacin ? carbadox? ???? ? ??? ? ????.
??
(1) ??? ?????? ?? ????? (PC) (???? ??? ?), ?? 2 ?? ????, ??????? ?? ??? ??? ? ????.
(2) ?? ???? ??? ?????? ???, ?? ? ???, ????, ?? ??? ?? ?? ??? ??? ??? ??? ? ????.
(3) ??? ????? ??? ?????? ?? ?? ???????? ??? ???? ?? ???? ???? ???, ??? (?? ???)? ??? ?????.
(4) ??? ????? ? ?? ??? ??? (?? tert ?? ??? MTBE? ?? ? ? ??), ???? ?? ??? ??? ??? ? ????.
(5) ??? ?????? ??? ?? ??? ??? ????? ?? ? ??? ???? ???, ?? ?, ?? ?????, ??? ?? ?? ?? ?? ?? ?? ? ? ????.
??, ?? ? ??
1. ??? ??? ??? ??????? ??????.
2. ?? ? ??? ??????. ???? ???? ??? ??? ?? ??? ??????.
??
Environmentally benign substitute for dimethyl sulfate, q.v., and methyl halides in methylation reactions and for phosgene, q.v., in methylcarbonylation reactions.
?? ??
Dimethyl carbonate (DMC) is formed by the reaction of MeOH with phosgene or methyl chloroformate in the presence of a concentrated sodium hydroxide solution in a two-phase reaction in high yields and purity. Other alcohols can also be phosgenated. As DMC is now more easily accessible via the direct oxidative carbonylation of MeOH, phosgenation is losing its attractiveness in this application.
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ChEBI: Dimethyl carbonate is a carbonate ester that is carbonic acid in which both hydrogens are replaced by methyl groups. A flammable, colourless liquid (m.p. 2-4°C, b.p. 90°C) with a characterstic ester-like odour, it is used as a 'green' methylating agent and as a solvent. It has a role as a solvent and a reagent.
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Dimethyl carbonate appears as a clear, colorless liquid with a pleasant odor. Denser than water and slightly soluble in water. Vapors are heavier than air. Used to make other chemicals and as a special purpose solvent.
??? ?? ??
Highly flammable. Slightly soluble in water.
?? ???
Dimethyl carbonate reacts with acids to liberate heat along with methanol and carbon dioxide. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction with caustic solutions. Flammable hydrogen is generated by mixing with alkali metals and hydrides.
???
Flammable, dangerous fire risk. Toxic by
inhalation, strong irritant.
????
May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
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HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
Safety Profile
Moderately toxic by
intraperitoneal route. Mildly toxic by
ingestion. An irritant. Violent reaction or
ignition on contact with potassium-tertbutoxide. A very dangerous fire hazard
when exposed to heat, open flames (sparks),
or oxiduers. To fight fire, use alcohol foam.
When heated to decomposition it emits
acrid smoke and irritating fumes.
Purification Methods
If the reagent has broad intense bands at 3300cm-1 and above (i.e. OH stretching), then it should be purified further. Wash it successively with 10% Na2CO3 solution, saturated CaCl2, H2O, and dry it by shaking mechanically for 1hour with anhydrous CaCl2, and fractionate. [Bowden & Butler J Chem Soc 78 1939, Vogel J Chem Soc 1847 1948, Beilstein 3 IV 3.]
??? ????? ?? ?? ? ???
???
?? ??
Boron trifluoride-DiMethyl carbonate coMplex
(1,3,5-????-1H-???-4-?)????
1-??????
4-DIMETHOXYMETHYL-6-HYDROXYPYRIMIDINE-2-THIOL
N-??-3-?????-4-???????
?????????????
Asulam
?? ?? ?????
7-Chloro-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylic acid
(S)-(-)-1,2,3,4-??????-????
1,3,5-????-1H-???-4-?????
1H-???-3-?????,?????-,??????(9CI)
???????
1,3,5-????-1H-???-4-????????
4-???-1,3,5-????-1H-???
1,3,5-???????
1H-???-4-?????????,1,3,5-????-(9CI)
??? ?????
3-?????
1,5-???????????
2-PHENYLMALONAMIDE
