CYCLIC OLEFIN MONOMER
Cyclopentene
Cyclopentene at ≥99.0% with cyclopentadiene ≤0.1% and sulfur ≤1 µg/mL, for polycyclopentene rubber, copolymers and pharmaceutical intermediates. Supplied in 150 kg lacquered iron drums or ISO tanks.
Samples are available for qualification testing before a bulk order.
Overview
Cyclopentene
Cyclopentene (C₅H₈) is a cyclic olefin with one reactive double bond in a five-membered ring. It is used as a monomer and co-monomer, and as the starting material for cyclopentane-ring intermediates such as cyclopentene oxide, cyclopentanediol and cyclopentylphenol.
The grade on this page is ≥99.0% cyclopentene with cyclopentadiene ≤0.1% and sulfur ≤1 µg/mL. Cyclopentadiene is the main reactive impurity in this product. Sulfur is limited because it poisons many of the metal catalysts used to polymerize, hydrogenate or functionalize cyclic olefins.
With a boiling point of 44 °C and a flash point of -29 °C, cyclopentene needs cool storage and dangerous-goods handling.
Product identification
Product identification
| Product Name | Cyclopentene |
| CAS Number | 142-29-0 |
| HS Code | 2902.19 |
| Molecular Formula | C₅H₈ |
| Molecular Weight | 68.12 g/mol |
| Purity | ≥99.0% |
| Appearance | Colorless liquid |
Quality specification
Quality specification
Sales specification
| Parameter | Specification | Unit |
|---|---|---|
| Cyclopentene content | ≥ 99.0 | % |
| Cyclopentadiene | ≤ 0.1 | % |
| Sulfur | ≤ 1 | µg/mL |
| Density | 0.777 | g/mL |
What the limits mean
What the limits mean
Cyclopentadiene ≤0.1%
Cyclopentadiene is a conjugated diene. It dimerizes to dicyclopentadiene on storage and can act as a cross-linking diene in polymerization, so it is held to 0.1% or less.
Sulfur ≤1 µg/mL
Sulfur compounds deactivate many hydrogenation and metathesis catalysts. A 1 µg/mL ceiling protects catalyst life in downstream reactions.
Lacquered drums
Drums are internally lacquered to limit contact between the product and bare steel.
Applications
Applications by industry
1
Polymers and rubber
Monomer and co-monomer for specialty polymers.
Polycyclopentene (polypentenamer) rubber by ring-opening polymerization
Co-monomer in copolymers
2
Fine-chemical and pharmaceutical intermediates
Starting material for functionalized five-membered rings.
Cyclopentene oxide
Cyclopentanediol
Cyclopentylphenol
Pharmaceutical intermediates
Technical Specifications
Physical and chemical properties
| Parameter | Value | Unit |
|---|---|---|
| Boiling point | 44.2 | °C |
| Melting point | -135.1 | °C |
| Flash point | -29 | °C |
| Solubility in water | Practically insoluble | - |
| Vapor pressure (25 °C) | 48.3 | kPa |
Packaging & Shipping
Packaging, storage and transport
Packaging
Lacquered iron drum – 150 kg
ISO tank – Bulk
Shipping & Storage
Storage: Store in closed containers in a cool, well-ventilated area away from heat, ignition sources and oxidizers. The boiling point is 44 °C, so keep containers out of direct sun.
Hazardous: Yes - DG transport required
Origin: Produced by a large-scale C5 processing partner in Shandong, China. Easier Materials is the export partner.
Commercial terms: MOQ, lead time and delivery terms are quoted per enquiry.
Regulatory and transport data
| Item | Value |
|---|---|
| EC number | 205-532-9 |
| UN number | UN 2246 (cyclopentene) |
| Transport class and packing group | Class 3 (flammable liquid), packing group II |
| GHS signal word | Danger |
| GHS hazard statements | H225 (highly flammable liquid and vapor); H302 (harmful if swallowed); H304 (may be fatal if swallowed and enters airways); H312 (harmful in contact with skin); H315 (causes skin irritation). Some notifications add H319, H335 or H412. |
| HS code | 2902.19 (cyclanes, cyclenes and cycloterpenes, excluding cyclohexane). National 8- and 10-digit tariff lines differ by country. |
| Inventory listings | The substance is listed on the US TSCA inventory and has Japan METI number 3-3439. For EU REACH, registration dossiers for the substance are on the ECHA list; whether they cover a given import route is for the importer to confirm. |
Application chemistry
Cyclopentene is the common starting olefin of the oxygenated C5 products. Acid-catalyzed addition of acetic acid gives cyclopentyl acetate, and transesterification with methanol releases cyclopentanol. Oxidation with N₂O gives cyclopentanone. Producer literature states that CPME was developed using cyclopentene. Other derivatives named in supplier literature are cyclopentene oxide, cyclopentylphenol and cyclopentanediol.
Cyclopentene is the monomer of polypentenamer (polycyclopentene), made by ring-opening metathesis polymerization. Recent studies treat the polymer as recyclable: equilibrium ROMP of cyclopentene to a tire-additive polymer gave over 80% yield at 0 °C and depolymerized at 40 °C (2016); poly(cyclopentene) rubbers were depolymerized back to cyclopentene by ring-closing metathesis, at 0.001 mol% ruthenium catalyst and room temperature for pristine polymer and 1 mol% for vulcanized rubber, and copolymers with norbornene and DCPD also returned cyclopentene (2024); and ring-opening insertion metathesis of cyclopentene with unsaturated polyester oligomers gave cleavable polyolefins (2025).
How this grade compares
Laboratory catalogue grades of cyclopentene are listed at 96% and 97%; the grade on this page is specified at ≥99.0%, with cyclopentadiene ≤0.1% and sulfur ≤1 µg/mL.
In the published routes to cyclopentene, cracking of DCPD to cyclopentadiene followed by selective hydrogenation, cyclopentane is the usual by-product of over-hydrogenation, and it is hard to separate from cyclopentene by distillation (boiling points 49 °C and 44 °C). A process that needs a limit on cyclopentane or on another specific impurity states it in the enquiry.
Storage and shelf life
Small laboratory packs of cyclopentene are typically stored at 2–8 °C. The boiling point is 44 °C and the closed-cup flash point is below -20 °C, so bulk material is kept cool, out of direct sun and away from ignition sources.
Documentation
Documentation
TDS and MSDS available on request
FAQ
Frequently Asked Questions
Related Products
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