4-Vinylcyclohexene is an organic chemical compound with the molecular formula C₈H₁₂ and a molar mass of 108.18 g·mol⁻¹. The molecule consists of a cyclohexene ring bearing a vinyl substituent at the 4‑position (4‑ethenylcyclohex‑1‑ene). It is a colorless liquid at room temperature and is chiral, although it is typically employed as a racemic mixture.
Chemical and Physical Properties
- Appearance: Colorless liquid
- Density: 0.8299 g cm⁻³ (20 °C)
- Melting point: –108.9 °C
- Boiling point: 128.9 °C
- Flash point: 21.2 °C (70.2 °F)
- Auto‑ignition temperature: 269 °C (516 °F)
- Vapor pressure: ≈ 2 kPa at 25 °C
- Solubility: Slightly soluble in water (≈ 0.05 g L⁻¹); miscible with organic solvents such as benzene, diethyl ether, and petroleum ether
- Refractive index (n_D): 1.4639 (20 °C)
Production
4‑Vinylcyclohexene is produced industrially by the dimerization of 1,3‑butadiene via a Diels–Alder reaction. The process is carried out at temperatures between 110 °C and 425 °C and pressures ranging from 1.3 to 100 MPa in the presence of heterogeneous catalysts composed of silicon carbide combined with copper or chromium salts. A major competing reaction yields 1,5‑cyclooctadiene. In North America, the primary commercial manufacturer is Nippon Chemical Texas Inc. (Pasadena, Texas).
Applications
The compound is primarily used as an intermediate in the synthesis of other chemicals, most notably as a precursor to vinylcyclohexene dioxide, an epoxy resin monomer employed in polymer production.
Safety and Health Effects
- Classification: Group 2B carcinogen (possibly carcinogenic to humans) according to the International Agency for Research on Cancer (IARC).
- Acute toxicity: LD₅₀ (oral, rat) ≈ 2.6 g kg⁻¹.
- Hazard statements (GHS): H351 – “Suspected of causing damage to organs through prolonged or repeated exposure.”
- Precautionary statements: Include measures for handling, storage, personal protection, and emergency response (e.g., P201, P202, P281, P308 + P313, P405, P501).
Exposure to 4‑vinylcyclohexene may cause irritation of the respiratory tract and skin, and chronic exposure has been linked to reproductive toxicity in animal studies. Proper engineering controls, personal protective equipment, and adherence to occupational exposure limits are recommended when handling the substance.
Regulatory Information
- CAS Registry Number: 100‑40‑3
- EC Number: 202‑848‑9
- ECHA InfoCard ID: 100.002.590
- UNII: 212JQJ15PS
References
- Wikipedia contributors. “4‑Vinylcyclohexene.” Wikipedia, The Free Encyclopedia.
- Lide, D. R. (1998). Handbook of Chemistry and Physics (87th ed.). CRC Press.
- International Agency for Research on Cancer (IARC). “4‑Vinylcyclohexene.” IARC Monographs on the Evaluation of Carcinogenic Risks to Humans.
- Schiffer, T.; Oenbrink, G. “Cyclododecatriene, Cyclooctadiene, and 4‑Vinylcyclohexene.” Ullmann’s Encyclopedia of Industrial Chemistry, Wiley‑VCH.
All information presented reflects current, verifiable sources and does not include speculative content.