Carbonate ester
Carbonic acid esters (often inaccurately called carbonates ) are the esters of the unstable substance into carbonic acid. Your general semi- structural formula R1 -O -C ( = O )-O -R2, where R1 and R2 carbonaceous alkyl or aryl. In the case of R1 = R2, the carbonic acid ester symmetric, R1 ≠ R2 of the carbonic acid ester is unbalanced. R1 and R2 are on the same molecule, then a ring-shaped compound, such as propylene carbonate formed. Is the carbonic acid function on one side unfunctionalized (R = H), then one speaks of a half ester. The urethanes can also be classified as semi-esters of carbonic acid, at the same time they are half-amides of carbonic acid.
Production
Carbonic acid esters can be prepared from phosgene and alcohols with elimination of hydrogen chloride:
Use
Carbonic acid esters have to be quite polar solvent has a certain solubility of inorganic salts and are therefore, as liquid electrolyte (Li- ion ) batteries used. Especially known carbonic acid esters are the polycarbonates, which are widely used as plastics. The so-called triphosgene ( carbonic acid bis - trichloromethyl ) may be less dangerous substitute for phosgene are used in syntheses.
More
In addition to carbonic acid esters of the general formula CO (OR) 2 is also known as orthophosphoric acid esters C (OR ) 4 ( see also orthoesters ). These can be obtained by reaction of chloropicrin with alcoholates:
Examples
- Dimethyl carbonate
- Carbonic
- Ethylene
- Propylene carbonate
- Diphenyl carbonate