The key difference between phosgene and diphosgene is that phosgene has one carbon atom, one oxygen atom and two chlorine atoms whereas diphosgene has double the number of all these atoms.
Phosgene and diphosgene are organic compounds. Both these compounds contain carbon, oxygen and chlorine atoms. The number of each type of atoms in the diphosgene molecule is exactly the twice the number of those atoms in the phosgene molecule.
CONTENTS
1. Overview and Key Difference
2. What is Phosgene
3. What is Diphosgene
4. Similarities Between Phosgene and Diphosgene
5. Side by Side Comparison – Phosgene vs Diphosgene in Tabular Form
6. Summary
What is Phosgene?
Phosgene is an organic compound having the chemical formula COCl2. It is a colourless gas, and it has an odour similar to freshly cut grass. Although it is insoluble in water, it can react with water. Moreover, it has trigonal planar geometry, and Cl-C-Cl bond angle is 111.8°. This compound is a simple acyl chloride that forms from carbonic acid.
Figure 01: The Chemical Structure of Phosgene Molecule
In the industrial scale, we produce phosgene by passing pure carbon monoxide and chlorine gas through activated carbon. Here, activated carbon is the catalyst. Furthermore, this reaction is exothermic, and we must cool the reactor during the reaction. When considering the uses of phosgene, we can use it in the production of isocyanates, in the synthesis of carbonates, etc.
What is Diphosgene?
Diphosgene is an organic compound having the chemical formula C2O2Cl4. It is a colourless liquid at room temperature. It is an important reagent in organic synthesis reactions. Comparatively, diphosgene has low toxicity than phosgene. However, this liquid should be handled carefully than phosgene, which is a gas.
Figure 02: The Chemical Structure of Diphosgene Molecule
We can prepare diphosgene in the laboratory by radical chlorination of methyl chloroformate. This reaction requires the presence of a UV radiation source. Other than that, radical chlorination of methyl formate can also form diphosgene. Moreover, diphosgene converts into phosgene when heated or upon reaction with charcoal.
What are the Similarities Between Phosgene and Diphosgene?
- Phosgene and diphosgene are organic compounds.
- Both these compounds contain carbon, oxygen and chlorine atoms.
- These compounds are insoluble in water.
What is the Difference Between Phosgene and Diphosgene?
Phosgene is an organic compound having the chemical formula COCl2 while Diphosgene is an organic compound having the chemical formula C2O2Cl4. The key difference between phosgene and diphosgene is that phosgene has one carbon atom, one oxygen atom and two chlorine atoms whereas diphosgene has double the number of all these atoms.
Phosgene occurs as a colourless gas with an odour similar to that of freshly cut grass while diphosgene occurs as a colourless liquid at room temperature. Comparatively, diphosgene is less toxic than phosgene, but it needs to be handled carefully because diphosgene has relatively a high vapour pressure and decomposes to form phosgene at high temperatures. Moreover, phosgene is produced by passing pure carbon monoxide and chlorine gas through activated carbon while diphosgene is produced by radical chlorination of methyl chloroformate in the presence of a UV radiation source.
The following table summarizes the difference between phosgene and diphosgene.
Summary – Phosgene vs Diphosgene
Phosgene and diphosgene are organic compounds. Both these compounds contain carbon, oxygen and chlorine atoms. The key difference between phosgene and diphosgene is that phosgene has one carbon atom, one oxygen atom and two chlorine atoms whereas diphosgene has double the number of all these atoms.
Reference:
“Diphosgene.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 6 Dec. 2011, Available here.
“Diphosgene.” Diphosgene – an Overview | ScienceDirect Topics, Available here.
Image Courtesy:
1. “Phosgene-dimensions-2D” By Phosgene-dimensions-2D.png: Ben MillsSVG-version: n-regen – Phosgene-dimensions-2D.png (Public Domain) via Commons Wikimedia
2. “Diphosgene structure” By Ed (Edgar181) – Own work (Public Domain) via Commons Wikimedia