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Isoprene

IUPAC: 2-methylbuta-1,3-diene

C5H8 Organic Compounds CAS 78-79-5
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Quick Reference
Formula / NotationC5H8
CAS Number78-79-5
Molecular Weight68.12
Melting Point-184 °F (NTP, 1992)
Boiling Point93 °F at 760 mmHg (NTP, 1992)
Density0.681 at 68 °F (USCG, 1999) - Less dense than water; will float
Solubilityless than 1 mg/mL at 70.7 °F (NTP, 1992)
AppearanceIsoprene, stabilized appears as a clear colorless liquid with a petroleum-like odor. Density 5.7 lb / gal. Flash point -65 °F. Boiling point 93 °F. May polymerize exothermically if heated or cont...
Also Known As2-methylbuta-1,3-diene; 78-79-5; 2-Methyl-1,3-butadiene; 2-Methylbuta-1,3-diene; Isopentadiene; 2-Methylbutadiene; 2-Methyldivinyl; 1,3-Butadiene, 2-methyl-; beta-Methylbivinyl; 3-Methyl-1,3-butadiene
CategoryOrganic Compounds

What is Isoprene?

Isoprene can cause cancer according to The World Health Organization's International Agency for Research on Cancer (IARC).

Formula & Notation

C5H8

IUPAC Name: 2-methylbuta-1,3-diene

Other Names / Synonyms: 2-methylbuta-1,3-diene; 78-79-5; 2-Methyl-1,3-butadiene; 2-Methylbuta-1,3-diene; Isopentadiene; 2-Methylbutadiene; 2-Methyldivinyl; 1,3-Butadiene, 2-methyl-; beta-Methylbivinyl; 3-Methyl-1,3-butadiene

Properties & Characteristics

Appearance: Isoprene, stabilized appears as a clear colorless liquid with a petroleum-like odor. Density 5.7 lb / gal. Flash point -65 °F. Boiling point 93 °F. May polymerize exothermically if heated or cont.... Molecular formula: C5H8. Molecular weight: 68.12 g/mol. Boiling point: 93 °F at 760 mmHg (NTP, 1992). Melting point: -184 °F (NTP, 1992). Density: 0.681 at 68 °F (USCG, 1999) - Less dense than water; will float. Solubility: less than 1 mg/mL at 70.7 °F (NTP, 1992). Vapor pressure: 400 mmHg at 59.7 °F ; 493 mmHg at 68 °F (NTP, 1992). LogP: 2.5.

Physical Data

PropertyValue
Melting Point-184 °F (NTP, 1992)
Boiling Point93 °F at 760 mmHg (NTP, 1992)
Density0.681 at 68 °F (USCG, 1999) - Less dense than water; will float
Molecular Weight68.12
Solubilityless than 1 mg/mL at 70.7 °F (NTP, 1992)
AppearanceIsoprene, stabilized appears as a clear colorless liquid with a petroleum-like odor. Density 5.7 lb / gal. Flash point -65 °F. Boiling point 93 °F. May polymerize exothermically if heated or cont...

Uses & Applications

Used as an industrial feedstock, solvent, pharmaceutical intermediate, flavoring agent, or chemical building block.

Safety Information

Flammable or irritant. Many organic compounds are flammable liquids or vapours. Keep away from ignition sources. Consult SDS for specific hazard data.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Isoprene
Formula C5H8
CAS Number 78-79-5
Molecular Weight 68.12
Synonyms 2-methylbuta-1,3-diene; 78-79-5; 2-Methyl-1,3-butadiene; 2-Methylbuta-1,3-diene; Isopentadiene; 2-Methylbutadiene; 2-Methyldivinyl; 1,3-Butadiene, 2-methyl-; beta-Methylbivinyl; 3-Methyl-1,3-butadiene

Frequently Asked Questions

Isoprene can cause cancer according to The World Health Organization's International Agency for Research on Cancer (IARC).

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.