Hex-2-ene (592-43-8) Physical and Chemical Properties
Hex-2-ene
Hex-2-ene is an aliphatic internal alkene commonly used as a nonpolar solvent and chemical intermediate in petrochemical and specialty chemical synthesis.
| CAS Number | 592-43-8 |
| Family | Alkenes (aliphatic) |
| Typical Form | Colorless liquid |
| Common Grades | EP, JP |
Hex-2-ene is an acyclic, mono-olefin hydrocarbon of the C6 aliphatic series; structurally it is an internal alkene with the double bond located between C-2 and C-3. The molecule is typically encountered as a mixture of geometric isomers (cis- and trans-2-hexene) and has the molecular formula \(\mathrm{C}6\mathrm{H}\). Electronic structure is dominated by a C=C π-bond localized within an otherwise saturated hydrocarbon chain, giving a nonpolar overall character and low topological polar surface area.
As a simple alkene, hex-2-ene displays the usual reactivity profile of internal olefins: susceptibility to electrophilic addition (e.g., hydrohalogenation, halogenation), catalytic hydrogenation to saturated hexane, and transition-metal-catalyzed functionalization (e.g., hydroformylation, epoxidation). The compound is lipophilic (XLogP3-AA = 2.6) and lacks hydrogen-bond donor or acceptor functionality, which results in low water solubility and limited aqueous reactivity except via radical or catalytic oxidative pathways. The material is a clear, colorless liquid under ambient conditions and behaves as a volatile hydrocarbon with significant vapor pressure relative to alkanes of comparable carbon number.
In industrial contexts hex-2-ene is used primarily as a chemical intermediate in organic synthesis and as a component of hydrocarbon process streams. Common commercial grades reported for this substance include: EP, JP.
Physical Properties
Density and Phase
Phase at ambient temperature: clear, colorless liquid (experimental description: "Clear colorless liquid").
No experimentally established value for this property is available in the current data context for density. As a C6 aliphatic hydrocarbon, hex-2-ene is classically less dense than water and displays hydrophobic behavior; typical handling assumes a low-viscosity, low-polarity liquid.
Melting Point
No experimentally established value for this property is available in the current data context.
Boiling Point
No experimentally established value for this property is available in the current data context.
Vapor Pressure
Reported vapor pressure: \(150.0\,\mathrm{mmHg}\). (Temperature for this measurement is not specified in the available data.)
Retention behavior on non-polar columns (Kovats indices, multiple reported values): - Standard non-polar: 598; 602.7; 610.9 - Semi-standard non-polar: 604; 607
These retention-index values are consistent with a moderately volatile C6 olefin and are useful for chromatographic identification on non-polar stationary phases.
Viscosity
No experimentally established value for this property is available in the current data context.
Chemical Properties
Flammability and Combustion
Hex-2-ene is a highly flammable liquid and vapor (GHS hazard classification includes H225). It is associated with an aspiration hazard (H304). Vapors can form explosive mixtures with air; standard flammable-liquid precautions apply. Combustion of hex-2-ene produces the usual hydrocarbon combustion products—primarily \(\mathrm{CO}_2\) and \(\mathrm{H}_2\mathrm{O}\) under complete combustion, with carbon monoxide, soot and other partially oxidized products possible in oxygen-limited conditions.
Reported hazard statements (as supplied): H225 (100%): Highly Flammable liquid and vapor. H304 (98.4%): May be fatal if swallowed and enters airways. Precautionary statement codes reported include P210, P233, P240, P241, P242, P243, P280, P301+P316, P303+P361+P353, P331, P370+P378, P403+P235, P405, and P501.
Reactivity and Typical Transformations
Hex-2-ene, as an internal alkene, undergoes typical electrophilic and catalytic transformations: - Electrophilic addition reactions (hydrohalogenation, halogenation, acid-catalyzed hydration) producing substituted hexanes or functionalized products. - Catalytic hydrogenation to n-hexane under H2 and a suitable metal catalyst. - Transition-metal-catalyzed hydroformylation and hydrofunctionalization to yield aldehydes and oxygenates useful as intermediates. - Epoxidation of the double bond and subsequent ring-opening reactions. - Radical-mediated oxidation and oxidative cleavage under strong oxidative conditions. - Isomerization between geometric isomers (cis/trans) and double-bond migration under acidic or catalytic conditions; the presence of a mixture of stereoisomers is typical for commercial material.
The molecule contains no polar functional groups and shows negligible acid–base activity; hydrolysis is not a relevant pathway under ordinary conditions. Polymerization risk is low for simple internal olefins but radical polymerization or oligomerization can occur under strong radical-generating or catalytic conditions.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS number: 592-43-8
- EC number: 209-755-2
- ChEBI ID: CHEBI:229288
- DSSTox Substance ID: DTXSID10860334
- InChIKey: RYPKRALMXUUNKS-UHFFFAOYSA-N
- InChI: InChI=1S/C6H12/c1-3-5-6-4-2/h3,5H,4,6H2,1-2H3
- SMILES: CCCC=CC
- Molecular formula: \(\mathrm{C}6\mathrm{H}\)
- Molecular weight: 84.16
- Exact mass: 84.093900383
- Monoisotopic mass: 84.093900383
- XLogP3-AA: 2.6
- Topological polar surface area (TPSA): 0
- Hydrogen bond donor count: 0
- Hydrogen bond acceptor count: 0
- Rotatable bond count: 2
- Heavy atom count: 6
- Formal charge: 0
- Complexity: 35.3
- Undefined bond stereocenter count: 1
(Structural identifiers such as SMILES and InChI are provided verbatim as shown above.)
Synonyms and Structural Names
Reported synonyms and variant names include (selection from depositor-supplied synonyms and removed synonyms lists): - hex-2-ene - 2-hexene - 2-HEXENE - 2-Hexene, cis + trans - 2-Hexene (cis- and trans- mixture) - cis-2-hexene - trans-2-hexene - Methylpentaene - Hexene-(2) - 2-aHexene
Additional registry or collection identifiers appear in depositor lists; the above are common systematic and trivial names used for this connectivity/isomer set.
Industrial and Commercial Applications
Use as Solvent or Fuel Component
Hex-2-ene is used as a chemical intermediate in organic synthesis and petrochemical processing. As an internal olefin with moderate volatility and lipophilicity, it can be encountered as a feedstock for catalytic transformations (hydrogenation, hydroformylation, alkylation) and is compatible with hydrocarbon processing streams. It is not typically used where polar solvent properties are required.
Representative Use Scenarios
Representative industrial scenarios include: - Intermediate in manufacture of higher-value oxygenates, aldehydes or alcohols via hydroformylation and subsequent processing. - Feedstock for hydrogenation to produce saturated hydrocarbons (hexane isomers) used in formulations or as solvents. - Component of hydrocarbon mixtures in laboratory and process settings where a C6 olefinic fraction is required.
Common commercial grades reported for this substance include: EP, JP.
If a concise application summary is required but absent here, in practice selection of hex-2-ene for a process is based on its olefinic reactivity, volatility, and compatibility with hydrocarbon process equipment.
Safety and Handling Overview
Flammability Hazards
Hex-2-ene is classified as a highly flammable liquid and vapor (H225) and presents an aspiration hazard (H304). Vapors are heavier or lighter than air depending on temperature and can travel to distant ignition sources and flash back. Control measures should include elimination of ignition sources, grounding and bonding during transfer, use of explosion-proof electrical equipment, and adequate ventilation to prevent vapor accumulation.
Storage and Handling Considerations
Store in a cool, well-ventilated area away from strong oxidizers and sources of ignition. Use tightly closed containers constructed of compatible materials and consider inerting and grounding for large transfers to minimize static discharge risk. For handling, use appropriate personal protective equipment (chemical-resistant gloves, eye protection, protective clothing) and respiratory protection if engineering controls do not maintain exposures below regulatory or organizational limits. Avoid ingestion, inhalation of vapors, and prolonged skin contact; acute solvent effects on the central nervous system have been associated with exposure to hydrocarbon solvents of this class.
For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
