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Names | |||
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Preferred IUPAC name
Propa-1,2-diene
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Other names
Allene
Propadiene |
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Identifiers | |||
3D model (Jmol)
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1730774 | |||
ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.006.670 | ||
EC Number | 207-335-3 | ||
860 | |||
MeSH | Propadiene | ||
PubChem CID
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UN number | 2200 | ||
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Properties | |||
C3H4 | |||
Molar mass | 40.07 g·mol−1 | ||
Appearance | Colorless gas | ||
Melting point | −136 °C (−213 °F; 137 K) | ||
Boiling point | −34 °C (−29 °F; 239 K) | ||
log P | 1.45 | ||
Hazards | |||
Safety data sheet | External MSDS | ||
EU classification (DSD)
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F+ | ||
R-phrases | R12 | ||
S-phrases | S9, S16, S33 | ||
NFPA 704 | |||
Explosive limits | 13% | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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what is ?) | (|||
Infobox references | |||
Propadiene is the organic compound with the formula H2C=C=CH2. It is the simplest allene or compound with two adjacent C=C double bonds, and can also be identified as allene. As a constituent of MAPP gas, it has been used as a fuel for specialized welding.
Allene exists in equilibrium with methylacetylene (or propyne), the mixture sometimes being called MAPD for methylacetylene-propadiene:
for which Keq = 0.22 at 270 °C or 0.1 at 5 °C. MAPD is produced as a side product, often an undesirable one, of cracking propane to produce propene, an important in the chemical industry. MAPD interferes with the catalytic polymerization of propene.