4-VINYLCYCLOHEXENE

4-Vinylcyclohexene is an unsaturated cyclic hydrocarbon used principally as a chemical intermediate. Its molecular structure contains a terminal vinyl group and an internal cyclohexene double bond, allowing selective epoxidation, hydrogenation, oxidation, polymerization, and other functionalization reactions.

Commercial material is normally supplied as a stabilized, clear, colorless to light-yellow liquid. Stabilization is essential because 4-Vinylcyclohexene can oxidize, form hazardous peroxides, or polymerize during storage and processing.

CHEMICAL IDENTITY AND SYNONYMS

Chemical Name: 4-Vinylcyclohexene
IUPAC Name: 4-Ethenylcyclohex-1-ene
CAS Number: 100-40-3
EC Number: 202-848-9
Molecular Formula: C8H12
Molecular Weight: 108.18 g/mol
Chemical Class: Unsaturated cyclic hydrocarbon
Abbreviation: 4-VCH or VCH
SMILES: C=CC1CCC=CC1
InChIKey: BBDKZWKEPDTENS-UHFFFAOYSA-N

Common names include 4-Vinyl-1-cyclohexene, 4-ethenyl-1-cyclohexene, 4-ethenylcyclohexene, 4-vinylcyclohex-1-ene, 1-vinyl-3-cyclohexene, cyclohexenylethylene, butadiene cyclic dimer, and butadiene dimer. The established substance identity is recorded as 4-ethenylcyclohex-1-ene with CAS 100-40-3. Chemical identity record

4-Vinylcyclohexene should not be confused with vinylcyclohexane, ethylcyclohexene, ethylcyclohexane, cyclohexene, 1,5-cyclooctadiene, 4-vinylcyclohexene monoxide, or 4-vinylcyclohexene dioxide. These substances have different functionality, stability, processing behavior, and hazard classifications.

PHYSICAL AND CHEMICAL PROPERTIES

4-Vinylcyclohexene is a mobile, low-viscosity liquid with a characteristic hydrocarbon odor. It is practically insoluble in water but soluble in many common organic solvents.

Appearance: Clear, colorless to light-yellow liquid
Physical State: Liquid at 20°C
Boiling Point: Approximately 128°C
Melting Point: Approximately -109°C
Density: Approximately 0.83 g/cm³
Flash Point: Approximately 16°C, closed cup
Autoignition Temperature: Approximately 269°C
Vapor Pressure: Approximately 2.1 kPa at 25°C
Relative Vapor Density: Approximately 3.7, with air equal to 1
Explosive Limits in Air: Approximately 0.8–9.1% by volume
Water Solubility: Approximately 50 mg/L at 25°C
Log Pow: Approximately 3.93
Kinematic Viscosity: Approximately 0.84 mm²/s at 20°C
Refractive Index: Approximately 1.46

These values describe the pure substance or representative stabilized material. Commercial values can vary slightly with purity, inhibitor concentration, analytical method, and product grade. The principal physical and safety values are summarized in the current international chemical safety card. International safety card

STRUCTURE AND REACTIVITY

4-Vinylcyclohexene contains two chemically distinct carbon–carbon double bonds. One is located in the cyclohexene ring, while the second is a terminal vinyl group.

This difference permits controlled functionalization. Selective epoxidation of the ring double bond can produce 4-Vinylcyclohexene monoxide while retaining the terminal vinyl functionality. Further epoxidation converts both double bonds and produces 4-Vinylcyclohexene dioxide.

The terminal vinyl group can participate in free-radical addition, grafting, and copolymerization reactions. The internal double bond provides a separate site for epoxidation, hydrogenation, oxidation, or addition chemistry.

4-Vinylcyclohexene reacts with strong oxidizing agents and can develop unstable peroxide species during exposure to air. Heat, contamination, depleted inhibitor, and prolonged storage can accelerate oxidation or uncontrolled polymerization.

PRODUCTION AND COMMERCIAL FORM

4-Vinylcyclohexene is produced through the cyclic dimerization of 1,3-butadiene. In this reaction, two butadiene molecules combine through a cycloaddition pathway to form the substituted cyclohexene structure.

Industrial formation can occur intentionally under controlled temperature and pressure or unintentionally during butadiene production, purification, storage, polymerization, and synthetic-rubber processing. Competing reactions can produce other butadiene dimers and higher oligomers.

The crude product is separated by distillation and refined to control residual butadiene, cyclic-dimer composition, high-boiling oligomers, moisture, color, and other process impurities. A suitable inhibitor is then incorporated to maintain stability during packaging, transportation, and storage.

Commercial 4-Vinylcyclohexene is generally supplied as stabilized technical or synthesis grade. Representative commercial grades have assays in the 95–97% range, while application-specific refined grades may be produced to tighter impurity requirements.

Butylated hydroxytoluene is one commonly used stabilizer, with representative stabilized grades containing approximately 25–200 ppm. Tert-butylcatechol has also been used as an inhibitor. The inhibitor identity and concentration must be included in the procurement specification because they influence storage stability and downstream reaction performance. Representative stabilized-grade specification

APPLICATIONS AND INDUSTRIES

Epoxide and diepoxide production

The most important use of 4-Vinylcyclohexene is as a feedstock for 4-Vinylcyclohexene monoxide and 4-Vinylcyclohexene dioxide. Controlled epoxidation converts either one or both carbon–carbon double bonds into oxirane groups.

The monoepoxide retains a polymerizable vinyl group together with an epoxy group. This dual functionality enables polymerization followed by epoxy curing or chemical modification through the oxirane ring.

The diepoxide is a bifunctional cycloaliphatic epoxy intermediate. Its two epoxy groups allow formation of highly crosslinked materials when reacted with suitable curing agents.

Epoxidation requires carefully engineered temperature control, oxidant addition, reaction calorimetry, emergency cooling, compatible equipment, and peroxide management. The inhibitor system must be considered because stabilizers can influence oxidant consumption, catalyst activity, selectivity, and product purification.

Epoxy resins, coatings, and plastics

Derivatives produced from 4-Vinylcyclohexene are used in specialty epoxy resins, polyester systems, coatings, molded materials, and other crosslinked plastics. The cycloaliphatic structure can contribute rigidity, chemical resistance, electrical performance, and thermal properties to properly formulated derivative systems.

4-Vinylcyclohexene itself is primarily an intermediate rather than the final resin component. Final performance depends on the selected derivative, curing agent, catalyst, crosslink density, formulation additives, and cure schedule.

Polymer and polyolefin processing

4-Vinylcyclohexene has been used in polymer and polyolefin manufacture. Its terminal vinyl functionality can participate in addition reactions, while the remaining cyclic double bond provides a site for subsequent modification or crosslinking.

Potential functions include use as a comonomer, grafting substrate, unsaturated intermediate, or precursor to functional monomers. Polymerization behavior depends on initiator chemistry, temperature, inhibitor removal, monomer concentration, and the reactivity ratios of the selected comonomers.

Removing or deactivating the stabilizer before polymerization increases reactivity but also increases the risk of uncontrolled heat release. Polymerization operations therefore require temperature monitoring, controlled initiator addition, emergency inhibition, pressure relief, and validated maximum safe operating limits.

Specialty chemical synthesis

4-Vinylcyclohexene has been used as an intermediate in selected manufacturing routes for flame-retardant intermediates, plasticizers, antioxidants, fragrances, flavors, and other specialty chemicals. It may also serve as a starting hydrocarbon for oxidation, hydroformylation, hydrogenation, and carbon–carbon bond-forming reactions.

These are intermediate uses and do not imply that unreacted 4-Vinylcyclohexene is suitable for direct consumer, food, fragrance, or agricultural application. Residual-substance limits, derivative identity, toxicological requirements, and applicable regulations must be addressed for the finished product.

Published industrial assessments identify epoxide production, polyolefin manufacture, solvent use, and specialty-chemical synthesis as established or historical uses. Industrial-use assessment

Solvent and reaction-medium applications

4-Vinylcyclohexene has been used as a hydrocarbon solvent or reaction medium in specialized processes. Its low water solubility and compatibility with nonpolar organic materials can support liquid–liquid separations and hydrocarbon-phase reactions.

Its low flash point, peroxide-forming potential, toxicity profile, and suspected carcinogenicity substantially restrict routine solvent use. Closed equipment, vapor recovery, exposure control, and recovery-system stability are necessary when it is selected as a process solvent.

Butadiene and synthetic-rubber operations

4-Vinylcyclohexene can form as a secondary product wherever 1,3-butadiene is processed. It may be present in purge streams, recovered hydrocarbon fractions, polymerization residues, and synthetic-rubber manufacturing operations.

Monitoring is relevant because its boiling point is much higher than that of butadiene, allowing it to accumulate in selected equipment or heavier process fractions. Process design may involve controlled recovery, destruction, recycling, or separation of the accumulated dimer.

Analytical and research applications

High-purity stabilized 4-Vinylcyclohexene is used in analytical studies, reaction-development work, polymer research, toxicology, and the preparation of reference materials or functional derivatives.

Laboratory quantities should receive the same fire, peroxide, carcinogenicity, and aspiration-hazard controls as industrial material. Small container size does not eliminate the need for stabilization and peroxide management.

GRADE SELECTION AND QUALITY PARAMETERS

Selection of 4-Vinylcyclohexene should begin with the downstream reaction. Epoxidation, polymerization, analytical work, and general intermediate synthesis can require different limits for purity, inhibitor, peroxide value, water, and high-boiling residues.

Important procurement parameters include:

Assay by gas chromatography
Inhibitor identity
Inhibitor concentration
Peroxide value
Appearance and color
Water content
Density
Refractive index
Distillation range
Residual butadiene
Other butadiene dimers
High-boiling oligomers
Nonvolatile residue
Manufacturing and stabilization date
Retest period or shelf life
Packaging configuration
Certificate of Analysis and Safety Data Sheet requirements

For epoxidation, the impurity profile can influence oxidant demand, catalyst consumption, reaction selectivity, color, and distillation behavior. The inhibitor may need to be accommodated or reduced through a controlled process.

For polymerization, both the initial inhibitor concentration and the procedure used to remove or overcome it are critical. Insufficient inhibitor removal can delay conversion, while uncontrolled removal can create storage and reaction hazards.

For analytical work, higher assay and a defined impurity chromatogram may be more important than bulk economics. The analytical method should distinguish 4-Vinylcyclohexene from related butadiene dimers and oxidation products.

STABILIZATION AND PEROXIDE CONTROL

4-Vinylcyclohexene should be stored only in stabilized form. The stabilizer type, concentration, expected depletion rate, storage temperature, and headspace requirements must be treated as part of the product specification.

Inhibitor performance can depend on oxygen availability and the chemistry of the selected stabilizer. Headspace purging, nitrogen blanketing, or repeated opening of the container should not be changed without reviewing the requirements of the actual inhibitor system.

Exposure to air can generate hydroperoxides. Peroxide concentration should be checked before distillation, concentration, extended heating, or processing material that has exceeded its recommended storage period.

Material containing elevated peroxide levels must not be distilled or concentrated without an approved treatment procedure. Distillation to dryness must be avoided because unstable residues can become concentrated in the reboiler or remaining liquid.

Increasing viscosity, unexpected temperature rise, pressure development, discoloration, solids, or rapid peroxide growth can indicate product deterioration. Suspect material should be isolated and assessed by trained personnel.

STORAGE AND HANDLING

4-Vinylcyclohexene should be stored in a cool, dark, fire-resistant, well-ventilated area in tightly closed compatible containers. Storage should be separated from heat, sparks, open flames, oxidizing agents, polymerization initiators, and incompatible reactive chemicals.

The product should be protected from uncontrolled heating and direct sunlight. Storage temperature must remain within the range specified for the supplied inhibitor system.

Containers, pumps, and receiving equipment should be grounded and bonded. Electrical installations and ventilation equipment should be suitable for flammable-vapor service, and non-sparking tools should be used.

Compressed air should not be used for filling, discharging, mixing, or transferring 4-Vinylcyclohexene. Closed pumping or inert-pressure transfer should follow the requirements of the established stabilizer and process-safety system.

Local exhaust ventilation or a closed handling system is recommended. Operators should avoid breathing vapor and prevent contact with skin, eyes, and clothing.

SAFETY AND HAZARD INFORMATION

4-Vinylcyclohexene is a highly flammable liquid and vapor. At normal ambient temperatures, evaporation can quickly create a hazardous atmosphere, and vapor–air mixtures can ignite or explode.

The material causes skin irritation and can cause significant eye injury. Swallowed liquid may enter the lungs during ingestion or vomiting and cause aspiration pneumonitis, which can be fatal.

4-Vinylcyclohexene is treated as a suspected carcinogen. Animal studies also support concern for reproductive toxicity, including effects on ovarian function after repeated exposure.

Applicable classifications may include suspected reproductive toxicity and target-organ toxicity following prolonged or repeated exposure. Occupational exposure should therefore be minimized through containment, ventilation, hygiene controls, and appropriate personal protective equipment.

The product is toxic to aquatic organisms and may cause long-lasting environmental effects. Discharge to drains, soil, surface water, and groundwater must be prevented.

Protective equipment should include chemical-resistant gloves, protective clothing, safety goggles, and face protection when splash exposure is possible. Respiratory protection should be selected through a formal exposure assessment when engineering controls cannot adequately control vapor.

FIRST AID

Inhalation: Move the exposed person to fresh air and keep the person at rest. Obtain medical attention for coughing, headache, dizziness, breathing difficulty, significant exposure, or persistent symptoms.

Skin Contact: Remove contaminated clothing and footwear immediately. Rinse the skin thoroughly with plenty of water and wash with soap. Obtain medical advice if irritation develops or exposure was extensive.

Eye Contact: Rinse cautiously with clean water for at least 15 minutes. Remove contact lenses when present and easy to remove, continue rinsing, and obtain prompt medical attention.

Ingestion: Obtain emergency medical assistance immediately. Do not induce vomiting because of the serious aspiration hazard, and do not give anything by mouth to an unconscious person.

FIRE AND SPILL RESPONSE

Suitable extinguishing media include alcohol-resistant foam, dry chemical powder, and carbon dioxide. Water spray can be used to cool fire-exposed containers, but a direct water jet may spread the burning liquid.

Firefighters require full protective equipment and positive-pressure self-contained breathing apparatus. Heated containers may rupture or vent flammable vapor and should be cooled from a protected position.

For spills, remove all ignition sources, restrict access, ventilate the area, and use non-sparking equipment. Recover free liquid into compatible sealable containers and absorb remaining material with dry sand or another inert absorbent.

Spilled product must not be washed into sewers. Contaminated absorbent, soil, equipment, and packaging should be managed as hazardous waste in accordance with applicable regulations.

TRANSPORT INFORMATION

Stabilized 4-Vinylcyclohexene is commonly transported as:

UN Number: UN 1993
Proper Shipping Name: Flammable liquid, n.o.s.
Technical Name: 4-Vinylcyclohexene
Hazard Class: 3
Packing Group: II

The final transport description must follow the current Safety Data Sheet, inhibitor composition, package size, destination, and applicable road, sea, rail, or air regulations.

PACKAGING AND SUPPLY

4-Vinylcyclohexene can be supplied in compatible tightly closed bottles, drums, intermediate bulk containers, or bulk configurations according to quantity and transport requirements. Packaging must preserve inhibitor effectiveness, prevent contamination, control vapor release, and withstand flammable-liquid transportation conditions.

Each package should be traceable to its production batch and accompanied by the agreed analytical documentation. Storage history, inhibitor level, peroxide value, and product age are particularly important when the material will be heated, distilled, epoxidized, or polymerized.

Ataman Kimya supports 4-Vinylcyclohexene procurement for epoxide production, polymer and resin intermediates, specialty synthesis, analytical work, and industrial process applications. Product selection can be coordinated according to assay, inhibitor system, peroxide limit, impurity profile, packaging, documentation, and delivery requirements.

For specifications, availability, packaging options, and commercial inquiries, contact Ataman Kimya.

Phone: +90 216 577 10 10
Email: info@atamankimya.com