Ethylene (Ethene)
The world's highest-volume petrochemical. A colourless, flammable gas that forms the backbone of polyethylene, ethylene oxide, ethylene glycol, styrene and the entire PVC chain. Chelora supplies polymer-grade and chemical-grade ethylene with a Certificate of Analysis and full transport documentation on every shipment.
Molecular Structure
What is Ethylene?
Ethylene (IUPAC: ethene) is the simplest alkene: two sp²-hybridised carbon atoms joined by a carbon–carbon double bond (C=C), with two hydrogen atoms on each carbon. The molecule is planar, with bond angles close to 120°, a C=C bond length of 1.34 Å and a molecular weight of 28.05 g/mol.
At ambient conditions ethylene is a colourless, flammable gas with a faint sweet odour. It boils at −103.7 °C and its critical temperature is only 9.2 °C, so it cannot be kept liquid by pressure alone at normal temperatures: liquid ethylene is always refrigerated. The C=C double bond is the site of almost all of its industrial chemistry, from addition polymerisation to polyethylene, to epoxidation to ethylene oxide, to Wacker oxidation to acetaldehyde.
Global ethylene capacity is in the region of 200 million tonnes a year, more than any other organic chemical. No single molecule is more central to the modern polymer and chemical industry.
Chelora sources polymer-grade (≥99.9%) and chemical-grade (≥99.5%) ethylene from verified, asset-backed suppliers, with full documentation, origin certification and logistics support for Indian and international buyers.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
Ethylene's industrial chemistry is defined by its C=C double bond, the site of polymerisation, oxidation and most other reactions that convert it into downstream derivatives.
Structural formula — planar molecule, sp² carbons
Structural Identity
- IUPAC NameEthene
- Molecular FormulaC₂H₄
- Molecular Weight28.05 g/mol
- Hybridisationsp² (both C)
- Bond type (C–C)1 σ + 1 π (double)
- C=C bond length1.34 Å
- H–C–H bond angle117.4°
- H–C=C bond angle121.3°
- GeometryPlanar, D₂h symmetry
- CAS Number74-85-1
- InChI KeyVGGSQFUCUMXWEO-UHFFFAOYSA-N
Product Specifications
Chelora supplies ethylene in two principal commercial grades. The impurity lines below are the ones that decide whether a cargo runs cleanly through your catalyst, and each shipment's CoA reports them against the agreed specification. Custom limits are available for specific downstream processes.
| Parameter | Polymer grade | Chemical grade | Why it matters to you |
|---|---|---|---|
| Ethylene purity | ≥ 99.9 mol% | ≥ 99.5 mol% | Sets the inert load you carry through the reactor and purge from the recycle loop, and the yield per tonne bought. |
| Methane + ethane | ≤ 500 ppm vol | Per contract | Inert in most processes, but they build up in recycle gas and leave with the purge, taking ethylene with them. |
| Acetylene | ≤ 5 ppm vol | Per contract | Poisons polymerisation catalysts even at ppm levels and can form unstable acetylides with copper and silver. |
| CO + CO₂ | ≤ 5 ppm vol | Per contract | Carbon monoxide is one of the strongest poisons for Ziegler–Natta and metallocene catalysts. |
| Oxygen | ≤ 5 ppm vol | Per contract | Deactivates catalysts and is a safety concern in closed recycle systems. |
| Moisture | ≤ 10 ppm wt | Per contract | Water kills catalyst activity and can freeze or form hydrates in cold equipment. |
| Total sulfur | Reported, ppm wt | Per contract | Sulfur compounds poison polymerisation and hydrogenation catalysts. |
| Hydrogen | Reported, ppm vol | Per contract | Acts as a chain-transfer agent in polymerisation, so it moves melt index and molecular weight. |
Working to your own specification? Send us your purchase specification, including purity and every impurity limit your catalyst supplier sets, through the contact page. We will confirm which grade and source can meet it before you commit to a cargo.
Identity & physical data
| Chemical name | Ethylene (Ethene) |
|---|---|
| CAS Number | 74-85-1 |
| EC Number | 200-815-3 |
| Molecular formula | C₂H₄ |
| Molecular weight | 28.05 g/mol |
| Physical state (ambient) | Colourless gas |
| Boiling point | −103.7 °C at 1 atm |
| Melting point | −169.2 °C |
| Critical temperature | 9.2 °C |
| Critical pressure | 50.4 bar |
| Vapour density | 0.978 (air = 1) |
| Liquid density | 0.568 g/cm³ at boiling point |
Transport & classification
| UN Number (gas) | UN 1962 |
|---|---|
| UN Number (refrigerated liquid) | UN 1038 |
| Transport class | Class 2.1 (Flammable gas) |
| GHS hazard | Extremely flammable gas; gas under pressure |
| Supply forms | Pipeline, refrigerated liquid, compressed gas |
How ethylene is made
Almost all ethylene comes out of a steam cracker. Knowing the steps explains why acetylene, carbon oxides and moisture are the lines buyers watch: each one is either made in the furnace or must be removed downstream.
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Feedstock
Naphtha, ethane, propane, LPG or gas oil. Ethane gives the highest ethylene yield; naphtha also gives propylene, butadiene and aromatics.
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Steam cracking
The feed is mixed with steam and cracked in furnace coils at about 750–875 °C for a fraction of a second, then quenched to stop further reaction.
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Compression & treating
The cracked gas is compressed in stages, washed with caustic to remove CO₂ and H₂S, and dried so nothing freezes in the cold section.
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Separation
A chilled distillation train removes hydrogen and methane, hydrogenates acetylene, and splits ethylene from ethane in the C2 splitter.
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Polymer-grade ethylene
Stored refrigerated or sent by pipeline to derivative units, or shipped as refrigerated liquid to buyers without a cracker.
This product
Other routes supply the rest of the market: methanol-to-olefins (MTO), mostly in China, ethanol dehydration for bio-based ethylene, and propane or ethane dehydrogenation. Steam cracking remains by far the largest source worldwide.
Downstream Applications & Derivatives
Ethylene is the base olefin that feeds the broadest range of derivative chains in petrochemicals, from packaging films to antifreeze to engineering polymers.
Polyethylene (PE)
The single largest use, taking around 60% of all ethylene. HDPE and LLDPE are made with Ziegler–Natta, chromium or metallocene catalysts; LDPE is made by high-pressure free-radical polymerisation. Uses include film, packaging, pipe, blow-moulded containers and cable insulation.
Ethylene Oxide & Glycols
Vapour-phase oxidation of ethylene over a silver catalyst gives ethylene oxide (EO). EO is hydrated to monoethylene glycol (MEG), the feedstock for PET polyester and antifreeze, and also goes into surfactants and ethanolamines.
Styrene & Polystyrene
Alkylation of benzene with ethylene gives ethylbenzene, which is dehydrogenated to styrene monomer. Styrene feeds polystyrene, ABS, SBR rubber and expandable polystyrene (EPS) foam.
Vinyl Chloride & PVC
Ethylene is chlorinated or oxychlorinated to ethylene dichloride (EDC), which is cracked to vinyl chloride monomer (VCM), the feedstock for PVC, the third most widely produced synthetic polymer.
Ethanol, Acetaldehyde & VAM
Direct hydration of ethylene gives synthetic ethanol. Wacker oxidation gives acetaldehyde, and reacting ethylene with acetic acid and oxygen gives vinyl acetate monomer (VAM) for adhesives, paints and EVA.
Alpha-Olefins & Specialties
Oligomerisation of ethylene gives linear alpha-olefins (LAOs) such as 1-butene, 1-hexene and 1-octene, used as PE comonomers and in polyalphaolefin (PAO) lubricants, plasticiser alcohols and detergent alcohols.
What buyers check before they qualify a source
Four areas explain most of the catalyst upsets and off-spec batches we hear about when a plant takes ethylene from a new source.
Acetylene
Formed in the cracking furnace and removed by selective hydrogenation. A cargo from a cracker whose acetylene converter is running poorly can carry enough to poison a polymerisation catalyst.
Carbon oxides and oxygen
CO, CO₂ and O₂ at single-digit ppm can cut catalyst productivity sharply. Ask for them as separate lines on the CoA, not just a total.
Moisture and sulfur
Both are catalyst poisons and both can be picked up in storage and transfer. A clean product at the cracker can arrive wet if the logistics chain is not dry and dedicated.
Traceability
A CoA is only useful if it describes the parcel you received. Check that the sample point, date and batch match the cargo, and keep the documents with your receiving records.
Why source ethylene through Chelora Petrochem?
Verified Origin
Every consignment carries full origin certification and asset-backed supply chain documentation, with no grey-market or unverified intermediary supply.
Dual Grade Supply
Polymer grade (≥99.9%) and chemical grade (≥99.5%) available. Custom impurity specifications can be accommodated for specialist processes.
Complete Documentation
CoA, SDS, UN transport documents, REACH compliance and any destination-market certificates supplied with every shipment.
Logistics Management
Experienced in refrigerated and compressed ethylene logistics, by vessel, ISO tank, rail and cylinder, with a network suited to Indian and international delivery.
How ethylene is delivered
Ethylene's critical temperature is 9.2 °C, so it cannot be held as a liquid by pressure alone at normal temperatures. Liquid ethylene is always refrigerated; at ambient temperature it moves as compressed gas. The right form depends on your receiving infrastructure and annual volume.
Refrigerated liquid
Bulk & mid-volume buyersShipped fully refrigerated at about −104 °C near atmospheric pressure, or semi-refrigerated under pressure, in gas carriers and insulated ISO tanks. Received into refrigerated tanks or spheres.
- UN number
- UN 1038
- Typical modes
- Gas carrier, ISO tank
Compressed gas
Small & laboratory usersSupplied as high-pressure gas in cylinders, cylinder bundles or tube trailers for users with modest consumption and no refrigerated storage.
- UN number
- UN 1962
- Typical modes
- Cylinder, bundle, tube trailer
Pipeline
Integrated sitesWhere a regional ethylene pipeline network exists, plants take gas directly from crackers. Supply is arranged against the network's specification and metering.
- UN number
- Not applicable
- Typical modes
- Dedicated pipeline
Every cargo documented in full
Catalyst performance depends on what is in the ethylene, not on the grade name on the order. Each shipment comes with an analysis of the parcel you receive, so your quality and process teams can check it against your limits before it reaches the reactor.
- Certificate of Analysis for each shipment, with purity and the full impurity profile
- Safety Data Sheet to GHS/REACH standards
- Transport documents appropriate to the mode: sea, rail, road or cylinder
- Origin certificates and import-support documents for the destination market
- Specification confirmed before contract, so there are no surprises at discharge
What arrives with the cargo
Enough paperwork for your receiving, quality and safety teams to release the parcel.
- Certificate of Analysis
- Purity and impurity results for the parcel shipped, against the agreed specification.
- Safety Data Sheet
- Classification, exposure controls, storage, first aid, fire-fighting and spill response.
- Transport documents
- UN 1962 or UN 1038 dangerous-goods paperwork for the mode of transport.
- Origin & regulatory papers
- Certificates of origin and any registrations the destination market requires.
Storage & Handling Guidelines
Ethylene is a flammable gas that is also handled as a refrigerated liquid, so it needs strict engineering controls and operating discipline. The following is a summary; always refer to the full SDS before handling.
- Store cylinders or vessels in a well-ventilated, dedicated gas storage area away from ignition sources, heat and sunlight.
- All electrical equipment in storage and handling areas must be rated ATEX/IECEx for Zone 1 or Zone 2 as appropriate.
- Bond and earth all transfer equipment before and during any liquid or gas transfer.
- Keep ethylene away from strong oxidisers, halogens and materials that can generate static.
- Install continuous gas detection with audible and visual alarms set well below the lower explosive limit (LEL).
- Use only pressure-rated and, for liquid, low-temperature-rated piping, valves and fittings.
- Keep cylinders secured upright with chains or brackets, and protect valves with caps when not in service.
- Leak-check connections before and after use with suitable gas detection equipment.
Hazard Summary
Classification: Extremely flammable gas (GHS02) and gas under pressure (GHS04); may cause drowsiness or dizziness at high concentrations; simple asphyxiant. UN 1962 (gas), UN 1038 (refrigerated liquid).
Flammability: Flammable between 2.7% and 36% v/v in air, with an auto-ignition temperature of about 490 °C. Its faint odour gives no reliable warning, so never rely on smell to detect a leak; use gas detectors.
Asphyxiation: Ethylene is not acutely toxic but displaces oxygen in confined spaces. Monitor oxygen before entering any enclosed area where ethylene may accumulate.
Cold burns: Refrigerated liquid and expanding gas cause severe cold burns and make steel brittle. Use equipment rated for low temperature.
PPE minimum: Chemical-splash goggles, insulated cryogenic gloves for liquid handling, flame-retardant clothing, and supplied-air breathing apparatus where oxygen deficiency is possible.
Consult the full Safety Data Sheet for exposure limits, emergency response, spill containment and disposal before any use.
From enquiry to first cargo
Four steps from your first message to a supply pattern that matches your plant's consumption.
Send your requirement
Grade or specification, monthly or annual volume, supply form, delivery port or site, and timing.
Confirm the specification
We match your limits to a source and send a typical CoA and the SDS for your quality and safety teams.
Agree terms & logistics
Price, Incoterms, inspection, documentation and the transport mode that suits your receiving facilities.
Ship & repeat
Each cargo ships with its own CoA and documents, and repeat supply runs to the same agreed specification.
Frequently Asked Questions
Technical and commercial questions about ethylene sourcing and specifications, answered by the Chelora team.
What is ethylene used for in the petrochemical industry?
Ethylene is the world's highest-volume petrochemical. It is the main feedstock for polyethylene (HDPE, LDPE, LLDPE), ethylene oxide (EO), ethylene glycols (MEG, DEG), styrene, vinyl chloride monomer (VCM), vinyl acetate, ethanol and linear alpha-olefins. Polyethylene alone takes around 60% of global ethylene, with the rest spread across these derivative chains.
What is the difference between polymer grade and chemical grade ethylene?
Polymer grade ethylene (≥99.9% purity) meets the tight impurity limits required by Ziegler–Natta, chromium and metallocene polymerisation catalysts, where even ppm-level acetylene or CO can poison the catalyst. Chemical grade (≥99.5%) is used for EO/EG, ethylbenzene and other synthesis routes where catalysts are less sensitive. Chelora can supply both grades to specification, with a Certificate of Analysis for each shipment.
How is ethylene produced commercially?
The dominant route is steam cracking of hydrocarbon feedstocks such as naphtha, ethane, LPG or gas oil at about 750–875 °C, followed by quenching, compression and low-temperature distillation. Naphtha cracking dominates in Europe and Asia, while ethane cracking dominates in North America and the Middle East where natural gas liquids are abundant. Methanol-to-olefins (mostly in China), ethanol dehydration and dehydrogenation supply the rest of the market.
Which impurities matter most in polymer-grade ethylene?
Acetylene, carbon monoxide, carbon dioxide, oxygen, moisture and sulfur compounds, because each one poisons polymerisation catalysts at ppm levels. Hydrogen also matters because it changes polymer molecular weight. Ask for each impurity as its own line on the Certificate of Analysis and compare it with the limits your catalyst supplier sets.
Is ethylene flammable, and what special handling is required?
Yes. Ethylene is an extremely flammable gas, flammable between 2.7% and 36% v/v in air, with an auto-ignition temperature of about 490 °C. It must be handled with ATEX/IECEx electrical area classification, continuous gas detection set below the lower explosive limit, bonding and earthing of all transfer equipment, and strict control of ignition sources. Oxygen monitoring is needed wherever it could accumulate in a confined space.
In what physical form and packaging is ethylene supplied?
Ethylene is supplied as refrigerated liquid in gas carriers and insulated ISO tanks, as compressed gas in cylinders, bundles and tube trailers, or by pipeline where a network exists. Chelora arranges the form and transport mode that matches the buyer's receiving infrastructure and annual volume.
Why can't ethylene be stored as a liquid under pressure alone?
Its critical temperature is 9.2 °C. Above that temperature no amount of pressure will liquefy it, so at normal ambient temperatures ethylene can only be held as a compressed gas. Liquid ethylene is always refrigerated, either fully at about −104 °C close to atmospheric pressure, or partly refrigerated and held under pressure.
What are the UN numbers and transport class for ethylene?
Compressed ethylene gas is UN 1962 and refrigerated liquid ethylene is UN 1038. Both are Class 2.1, flammable gas, under the international dangerous-goods codes for sea, road, rail and air transport.
Is ethylene heavier or lighter than air?
Very slightly lighter. Its vapour density is about 0.98 relative to air, so it does not rise away quickly the way hydrogen or methane does; it mixes with air and can spread at ground level. Cold vapour from a liquid release is heavier than air until it warms, so it can collect in low points and drains.
Is ethylene used for fruit ripening?
Yes, in small quantities. Ethylene is a natural plant hormone, and low controlled concentrations are used in ripening rooms for bananas, mangoes and other fruit, usually from diluted gas mixtures or ethylene generators rather than pure gas. If you need ethylene for this use, tell us the volume and the form you need.
What are the key ethylene derivatives Chelora also supplies?
Chelora's petrochemical portfolio covers the main ethylene derivative chain, including ethylene oxide (EO), monoethylene glycol (MEG), diethylene glycol (DEG), styrene monomer, polyethylene (HDPE, LLDPE) and vinyl chloride monomer (VCM). Contact our sourcing team to discuss combined supply across the chain, often with freight and documentation savings.
What documentation does Chelora provide with each shipment?
Every shipment comes with a Certificate of Analysis (CoA) showing purity and the full impurity profile against the agreed specification, a Safety Data Sheet (SDS) to GHS/REACH standards, transport documents for the mode of transport, and any certificates of origin, import-support letters or registrations the destination market requires.
How do I request a quote for ethylene?
Send the grade or specification you need, your monthly or annual volume, the supply form, the delivery port or site and your timing through the contact page or to source@cheloragroup.com. Our sourcing team responds within one business day with a proposed source, a typical CoA and the SDS.
What is the CAS number and IUPAC name for ethylene?
Ethylene's CAS number is 74-85-1 and its IUPAC name is ethene. The molecular formula is C₂H₄ and the molecular weight is 28.05 g/mol. The molecule has two sp²-hybridised carbon atoms joined by a double bond (one σ bond and one π bond) with two hydrogen atoms on each carbon, giving a planar structure with bond angles close to 120°.
Request a quote or specification sheet
Talk to Chelora's sourcing team about ethylene grade, volume, logistics, documentation and lead times. We respond within one business day.