Isopentane, also known as 2-methylbutane, is a colorless, highly volatile hydrocarbon with the molecular formula C₅H₁₂ and CAS number 78-78-4. It has a gasoline-like odor, is practically insoluble in water, and floats on water because of its lower density. Its low boiling point makes it useful in applications requiring rapid vaporization, but it is also an extremely flammable liquid that requires carefully controlled handling.
Commercial products include Isopentane, 99% and Isopentane, 95%, with different specifications for polymerization-related processes and foam-blowing applications.
Isopentane in Drums
Isopentane in Isotank
Isopentane in drums and Isotank
Chemical Structure and Physical Properties
Isopentane is a branched-chain alkane with the condensed structural formula CH₃–CH(CH₃)–CH₂–CH₃. Its molecular weight is approximately 72.15 g/mol.
Unlike isopentane, n-pentane has a straight-chain structure: CH₃–CH₂–CH₂–CH₂–CH₃. The two compounds share the same molecular formula but differ in how their atoms are connected, making them structural isomers.
| Property | Typical Value or Description |
|---|
| Chemical name | Isopentane / 2-methylbutane |
| CAS number | 78-78-4 |
| Molecular formula | C₅H₁₂ |
| Molecular weight | Approximately 72.15 g/mol |
| Appearance | Clear, colorless liquid |
| Boiling point | Approximately 28°C / 82°F |
| Freezing point | Approximately −160°C |
| Density | Approximately 0.62 g/mL at 20°C |
| Flash point | Below −50°C; the reported value depends on the test method |
| Water solubility | Practically insoluble |
Physical-property values are approximate and should be checked against the applicable product safety data sheet and specification.
Isopentane’s very low flash point means it can produce ignitable vapors even at temperatures well below normal room temperature. Its vapor is heavier than air and may travel along the ground to a distant ignition source.
Main Uses of Isopentane
Foam Blowing Agents and Insulation Manufacturing
Isopentane is used as a physical blowing agent in expandable polystyrene (EPS) and polyurethane (PU) foam applications. Its volatility allows it to vaporize during processing and help form the foam’s cellular structure. Junyuan’s Isopentane, 95% is offered for these foam-blowing applications.
Isopentane is also supplied in blends with other pentanes. Relevant product ranges include:
These blend families serve different foam applications. Junyuan’s n-pentane/isopentane range includes standard ratios from 10/90 to 90/10, allowing customers to select a formulation suited to their process requirements.
Polyethylene Manufacturing
High-purity isopentane is used as an induced condensing agent in polyethylene production. In condensing-mode operation, it helps remove reaction heat. Product suitability depends not only on isopentane content but also on trace impurities such as water, sulfur, and unsaturated compounds.
For these applications, see Isopentane, 99%. The required specification should be confirmed against the polymerization process and catalyst system rather than selected on nominal purity alone.
Laboratory Tissue Freezing
Pre-cooled isopentane is used for rapid freezing of biological tissue before cryosectioning and other laboratory analyses. It may be cooled using liquid nitrogen or dry ice under an established laboratory procedure. This is distinct from simply storing specimens in liquid nitrogen.
Because the freezing medium is flammable, laboratories must follow appropriate ventilation, cryogenic-handling, and freezer-storage procedures. Residual flammable medium should be managed according to the validated tissue-preparation protocol before storage.
Binary-Cycle Geothermal Power Generation
Isopentane can serve as the working fluid in a binary-cycle geothermal power plant. Heat from geothermal water transfers to the isopentane through a heat exchanger, causing it to vaporize. The vapor drives a turbine connected to a generator.
Using a lower-boiling working fluid allows this type of plant to generate electricity from geothermal resources that are cooler than those typically used in conventional steam-based systems.
Isopentane in Drums and ISO Tanks
Junyuan offers both Isopentane, 99% and Isopentane, 95% in steel drums and ISO tanks. Packaging and shipment details should be confirmed for the selected grade and order.
When requesting a quotation, specify the required purity, application, quantity, packaging preference, destination port, and any limits on water, sulfur, or other impurities.
Safety, Storage, and Environmental Considerations
Isopentane is classified as an extremely flammable liquid and vapor. It may cause drowsiness or dizziness, can be fatal if swallowed and enters the airways, and is toxic to aquatic life.
Key precautions include:
- Keep it away from heat, sparks, open flames, and other ignition sources.
- Use closed handling systems, suitable ventilation, and explosion-protected equipment.
- Prevent static electricity buildup through appropriate grounding and bonding.
- Store containers tightly closed and separated from strong oxidizing agents.
- Prevent releases into drains, waterways, and low-lying spaces where vapor may accumulate.
For firefighting, suitable media may include dry chemical powder, carbon dioxide, or appropriate foam. A solid water jet can spread burning liquid and is not a suitable extinguishing method. Water spray may be used by trained responders for container cooling or other purposes specified in the safety data sheet. Always follow the current SDS and site emergency procedures.
For associated raw materials and foam-formulation requirements, explore:
For an isopentane inquiry, start with the 99% grade product page or the 95% grade product page and confirm the specification required for your application.