Propadiene
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| Names | |
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| IUPAC name
allene
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.006.670 |
PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| C3H4 | |
| Molar mass | 40.065 g·mol−1 |
| Melting point | −136.3 °C (−213.3 °F; 136.8 K) |
| Boiling point | −34.4 °C (−29.9 °F; 238.8 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Propadiene is the organic compound with the formula H2C=C=CH2. It is the simplest allene, a compound with conjoined C=C double bonds. Propadiene is also known as allene.[1] As a constituent of MAPP gas, it is used as a fuel for specialized welding.
Production and equilibrium with propyne
Allene exists in equilibrium with propyne, the mixture sometimes being called MAPD for methyl acetylene (alternative name of propyne)-propadiene:
- H3CC≡CH ⇌ H2C=C=CH2
Keq = 0.22 (270 °C), 0.1 K (5 °C) MAPD is produced as a side product, often an undesirable one, of cracking propane to produce propene, an important feedstock in the chemical industry. MAPD interferes with the catalytic polymerization of propene.[2]
References
- ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "allenes". doi:10.1351/goldbook.A00238
- ^ Klaus Buckl, Andreas Meiswinkel "Propyne" in Ullmann's Encyclopedia of Industrial Chemistry 2008, Wiley-VCH, Weinheim. doi:10.1002/14356007.m22_m01