Diphosgene
From Wikipedia, the free encyclopedia
| Diphosgene | |
|---|---|
  |
|
| General | |
| Systematic name | Diphosgene |
| Other names | trichloromethyl chloroformate |
| Molecular formula | C2Cl4O2 |
| SMILES | ? |
| Molar mass | 197.82 g/mol |
| Appearance | colorless crystals |
| CAS number | [[503-38-8] |
| Properties | |
| Density and phase | 1.65 g/cm3 solid |
| Solubility in water | insol. |
| Other solvents | most solvents |
| Melting point | ? °C (? K) |
| Boiling point | 128 °C |
| Structure | |
| Molecular shape | carbon: sp2 and sp3 |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | toxic |
| NFPA 704 | |
| Flash point | ? °C |
| R/S statement | R: 26/28-34 S: 26-28-36/37/39-45 |
| RTECS number | LQ7350000 |
| Supplementary data page | |
| Structure and properties |
n 1.458 |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | IR 1815 cm-1 |
| Related compounds | |
| Related compounds | COCl2, Cl2 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
|
Diphosgene is a chemical compound with the formula ClCO2CCl3. This colorless liquid is a valuable reagent in the synthesis of organic compounds. Diphosgene is related to phosgene but is more conveniently handled because it is a liquid, whereas phosgene is a gas.
Contents |
[edit] Production and uses
Diphosgene is prepared by radical chlorination of methyl chloroformate) under UV light.[1]
Diphosgene converts to phosgene upon heating or upon catalysis with charcoal. It is thus useful for reactions traditionally relying on phosgene. For example, it convert amines into isocyanates, secondary amines into carbamoyl chlorides, and carboxylic acids into acid chlorides. Diphosgene serves as a source of two equivalents of phosgene:
- 2 RNH2 + ClCO2CCl3 → 2 RNCO + 4 HCl
With α-amino acids diphosgene gives the acid chloride-isocyanates, OCNCHRCOCl, or N-carboxy-amino acid anhydrides depending on the conditions.[1]
It hydrolyzes to release HCl in humid air.
Diphosgene has supplanted phosgene in some large scale industrial reactions such as the production of (di-)isocyanates from of amines because it is safer to handle than phosgene.
[edit] Role in warfare
Diphosgene was originally developed for chemical warfare, a few months after the first use of phosgene. It was used as a poison gas in artillery shells by Germany during World War I. The first recorded battlefield use was in May of 1916. Diphosgene was developed because the vapors could destroy the filters in gas masks in use at the time.
[edit] Safety
Diphosgene has a relatively high vapor pressure of 10 mmHg (1.3 kPa) at 20 °C and decomposes to phosgene around 300 °C. Exposure to diphosgene is similar in hazard to phosgene and the MSDS should be consulted.
[edit] See also
[edit] References
- ^ Kurita, K. "Trichloromethyl Chloroformate" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
[edit] External links
- medical care guide.
- NATO guide, includes treatment advice
- material safety data sheet (PDF, for phosgene and diphosgene treated as one).
- Links to external chemical sources.
 |
||
|---|---|---|
| Blood agents: | Cyanogen chloride (CK) – Hydrogen cyanide (AC) | |
| Blister agents: | Lewisite (L) – Sulfur mustard gas (HD, H, HT, HL, HQ) – Nitrogen mustard gas (HN1, HN2, HN3) | |
| Nerve agents: | G-Agents: Tabun (GA) – Sarin (GB) – Soman (GD) – Cyclosarin (GF) – GV | V-Agents: VE – VG – VM – VX | Novichok agents | |
| Pulmonary agents: | Chlorine – Chloropicrin (PS) – Phosgene (CG) – Diphosgene (DP) | |
| Incapacitating agents: | Agent 15 (BZ) – KOLOKOL-1 | |
| Riot control agents: | Pepper spray (OC) – CS gas – CN gas (mace) – CR gas | |
