Diphosgene

Diphosgene
Diphosgene
Identifiers
CAS number 503-38-8
RTECS number LQ7350000
Properties
Molecular formula C2Cl4O2
Molar mass 197.82 g/mol
Appearance liquid at room temperature
Density 1.65 g/cm3
Melting point

-57 °C

Boiling point

128 °C

Solubility in water insol.
Hazards
R-phrases 26/28-34
S-phrases 26-28-36/37/39-45
Main hazards toxic
Related compounds
Related compounds COCl2, Cl2
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox 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

Production and uses

Diphosgene is prepared by radical chlorination of methyl chloroformate under UV light.[1]:

Cl-CO-OCH3 + 3 Cl2 —(hv)→ Cl-CO-OCCl3 + 3 HCl

Another method is the radical chlorination of methyl formate[2]:

H-CO-OCH3 + 4 Cl2 —(hv)→ Cl-CO-OCCl3 + 4 HCl

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, carboxylic acids into acid chlorides, and formamides into isocyanides. 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.[3]

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 amines because it is safer to handle than phosgene.

Role in warfare

Diphosgene was originally developed as a pulmonary agent 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 1916.[4] Diphosgene was developed because the vapors could destroy the filters in gas masks in use at the time.

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.

See also

References

  1. ^ Keisuke Kurita1 and Yoshio Iwakura (1979), "TRICHLOROMETHYL CHLOROFORMATE AS A PHOSGENE EQUIVALENT: 3-ISOCYANATOPROPANOYL CHLORIDE", Org. Synth. 59: 195, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0715 ; Coll. Vol. 6: 715 
  2. ^ Lohs, KH.: Synthetische Gifte; Berlin (east), 1974 (german)
  3. ^ Kurita, K. "Trichloromethyl Chloroformate" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
  4. ^ Jones, Simon; Hook, Richard (2007). World War I Gas Warfare Tactics and Equipment. Osprey Publishing. ISBN 1846031516. 

External links


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Look at other dictionaries:

  • diphosgène — ● diphosgène nom masculin Synonyme de surpalite. ● diphosgène (synonymes) nom masculin Synonymes : surpalite …   Encyclopédie Universelle

  • diphosgene — [dī fäs′jēn΄] n. a poisonous, liquid compound, ClCO2CCl3, related to phosgene and used as a lung irritant gas in chemical warfare …   English World dictionary

  • diphosgene — difosgenas statusas T sritis chemija apibrėžtis Kovinė nuodingoji medžiaga. formulė ClCOOCCl₃ atitikmenys: angl. diphosgene rus. дифосген ryšiai: sinonimas – trichlormetilchlormetanoatas …   Chemijos terminų aiškinamasis žodynas

  • diphosgene — difosgenas statusas T sritis apsauga nuo naikinimo priemonių apibrėžtis Dusinamoji nepatvarioji kovinė nuodingoji medžiaga. Pūvančių vaisių ir suplėkusio šieno kvapo bespalvis skystis. Lydymosi temperatūra 57 °C, virimo temperatūra 128 °C. Turi… …   Apsaugos nuo naikinimo priemonių enciklopedinis žodynas

  • diphosgene — noun Etymology: International Scientific Vocabulary Date: 1918 a liquid compound C2Cl4O2 used as a poison gas in World War I …   New Collegiate Dictionary

  • diphosgene — /duy fos jeen/, n. Chem. a colorless liquid, C2Cl4O2, usually derived from methyl formate or methyl chloroformate by chlorination: a World War I poison gas now used chiefly in organic synthesis. Also called trichloromethyl chloroformate. [1920… …   Universalium

  • diphosgene — noun The highly chlorinated ester trichloromethyl chloroformate that is used in organic synthesis, and was once used as a military poison …   Wiktionary

  • diphosgene — A poison gas used in World War I; it is also slightly lacrimatoric. * * * di·phos·gene ( )dī fäz .jēn n a liquid compound C2Cl4O2 used as a poison gas in World War I * * * di·phos·gene (di fosґjēn) a gas which is intensely irritating to the… …   Medical dictionary

  • diphosgene — n. poisonous gas …   English contemporary dictionary

  • diphosgene — di·phosgene …   English syllables

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