I

Isobutylene

IUPAC: 2-methylprop-1-ene

C4H8 Organic Compounds CAS 115-11-7
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Quick Reference
Formula / NotationC4H8
CAS Number115-11-7
Molecular Weight56.11
Melting Point-220.5 °F (NTP, 1992)
Boiling Point19.6 °F at 760 mmHg (NTP, 1992)
Density0.59 at 68 °F (USCG, 1999) - Less dense than water; will float
SolubilityInsoluble (NTP, 1992)
AppearanceIsobutylene is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its own vapor pressure. Contact with the liquid can ca...
Also Known As2-methylprop-1-ene; Isobutene; 2-Methylpropene; 115-11-7; 2-Methyl-1-propene; 2-Methylpropylene; 1,1-Dimethylethylene; gamma-Butylene; 1-Propene, 2-methyl-; Isopropylidenemethylene
CategoryOrganic Compounds

What is Isobutylene?

2-methylprop-1-ene is an alkene that is prop-1-ene substituted by a methyl group at position 2. It is a gas molecular entity and an alkene.

Formula & Notation

C4H8

IUPAC Name: 2-methylprop-1-ene

Other Names / Synonyms: 2-methylprop-1-ene; Isobutene; 2-Methylpropene; 115-11-7; 2-Methyl-1-propene; 2-Methylpropylene; 1,1-Dimethylethylene; gamma-Butylene; 1-Propene, 2-methyl-; Isopropylidenemethylene

Properties & Characteristics

Appearance: Isobutylene is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its own vapor pressure. Contact with the liquid can ca.... Molecular formula: C4H8. Molecular weight: 56.11 g/mol. Boiling point: 19.6 °F at 760 mmHg (NTP, 1992). Melting point: -220.5 °F (NTP, 1992). Density: 0.59 at 68 °F (USCG, 1999) - Less dense than water; will float. Solubility: Insoluble (NTP, 1992). Vapor pressure: 1 mmHg at -157.2 °F ; 5 mmHg at -141.7 °F (NTP, 1992). LogP: 2.1.

Physical Data

PropertyValue
Melting Point-220.5 °F (NTP, 1992)
Boiling Point19.6 °F at 760 mmHg (NTP, 1992)
Density0.59 at 68 °F (USCG, 1999) - Less dense than water; will float
Molecular Weight56.11
SolubilityInsoluble (NTP, 1992)
AppearanceIsobutylene is a colorless gas with a faint petroleum-like odor. For transportation it may be stenched. It is shipped as a liquefied gas under its own vapor pressure. Contact with the liquid can ca...

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 Isobutylene
Formula C4H8
CAS Number 115-11-7
Molecular Weight 56.11
Synonyms 2-methylprop-1-ene; Isobutene; 2-Methylpropene; 115-11-7; 2-Methyl-1-propene; 2-Methylpropylene; 1,1-Dimethylethylene; gamma-Butylene; 1-Propene, 2-methyl-; Isopropylidenemethylene

Frequently Asked Questions

2-methylprop-1-ene is an alkene that is prop-1-ene substituted by a methyl group at position 2. It is a gas molecular entity and an alkene.

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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.