Naphtha
The same word covers feedstocks optimised for opposite things. A steam cracker wants paraffins; a reformer wants naphthenes. Buying naphtha without stating which is buying a boiling range and hoping.
Molecular Structure
What is Naphtha?
Naphtha is a refinery distillate cut rather than a chemical. It boils roughly between 30 and 200 °C and contains paraffins, naphthenes and aromatics in proportions set by the crude slate and the processing route. Light naphtha covers the lower part of that range and is dominated by C5 and C6 paraffins; heavy naphtha covers the upper part and is richer in naphthenes and aromatics.
Its composition is described by PONA analysis — paraffins, olefins, naphthenes and aromatics — and that analysis is the specification that matters, because the two main consumers want opposite things. A steam cracker converts naphtha to ethylene and propylene, and paraffinic feed gives the highest olefin yield. A catalytic reformer converts naphtha to aromatics and high-octane gasoline, and naphthenic feed gives the best result because naphthenes dehydrogenate directly to aromatics.
Because naphtha is a UVCB defined by its process and boiling range, several CAS numbers cover material sold under the name — light straight-run, heavy straight-run, full range, hydrotreated and solvent grades all carry different registry numbers.
Naphtha's health classification is driven by what is in it rather than by the cut itself. Benzene content at or above 0.1 per cent brings a Category 1B carcinogen and mutagen classification, and n-hexane content brings the peripheral neurotoxicity concern that applies to that specific isomer. Both figures belong on the certificate.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
Not a compound but a mixture of hydrocarbon families in the same boiling range. Paraffins are straight or branched chains, naphthenes are saturated rings, aromatics carry a benzene ring — and the proportions between them determine what the cut is worth and to whom.
Representative components — paraffin, naphthene and aromatic
Structural Identity
- Substance typeUVCB — defined by process and boiling range
- Composition basisPONA analysis
- ParaffinsStraight and branched alkanes
- NaphthenesSaturated cyclic hydrocarbons
- AromaticsBenzene ring compounds
- Light naphtha≈ C₅ – C₆, paraffin rich
- Heavy naphtha≈ C₇ – C₁₀, naphthene and aromatic rich
- Cracker preferenceParaffinic — highest olefin yield
- Reformer preferenceNaphthenic — best aromatics yield
- CAS NumberVaries by cut — verify per grade
- Specified byDistillation, PONA, S, Hg, As
Product Specifications
Chelora supplies Naphtha in standard and custom grades. Contact us for specification sheets tailored to your process.
| Product | Naphtha, petroleum |
|---|---|
| CAS Number | Confirm against the specific cut and supplier registration |
| Substance type | UVCB refinery distillate |
| Initial boiling point | Declared per grade |
| Final boiling point | Declared per grade |
| Density at 15 °C | 0.650 – 0.780 g/cm³, cut dependent |
| Paraffins | Reported — governs cracker yield |
| Naphthenes | Reported — governs reformer yield |
| Aromatics | Reported |
| Olefins (max) | ≤ 1.0 vol% for straight-run cuts |
| Total sulphur (max) | ≤ 500 ppm wt; ≤ 0.5 ppm for reformer feed |
| Benzene content | Reported — drives health classification |
| n-Hexane content | Reported for solvent grades |
| Mercury (max) | ≤ 5 ppb wt — reformer catalyst poison |
| Arsenic (max) | ≤ 5 ppb wt — reformer catalyst poison |
| Chloride (max) | ≤ 1 ppm wt |
| Reid vapour pressure | Declared per grade |
| Doctor test / copper corrosion | Negative / Class 1 |
| Transport classification | UN 1268, Class 3, PG I or II by boiling point |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Naphtha.
Steam Cracker Feed
The largest petrochemical outlet. Paraffinic naphtha cracked to ethylene, propylene, butadiene and pyrolysis gasoline — the starting point for most of the polymer chain.
Catalytic Reforming
Naphthenic heavy naphtha reformed to benzene, toluene and xylenes and to high-octane reformate, with hydrogen as a valuable co-product.
Gasoline Blending
Light naphtha and isomerate as blending components, contributing front-end volatility and octane to the finished gasoline pool.
Solvent Grades
Hydrotreated and dearomatised cuts as industrial solvents for adhesives, cleaning, extraction and paint thinning, sold on aromatic and n-hexane content.
Ammonia & Hydrogen
Steam reforming of naphtha to synthesis gas for ammonia and hydrogen production where natural gas is unavailable or uncompetitive.
Fuel & Diluent
Diluent for heavy and bituminous crude to meet pipeline viscosity specification, and a component in certain industrial fuel blends.
Why source Naphtha through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation, with the refinery cut and its applicable CAS declared per cargo.
Grade Flexibility
Light, heavy and full-range cuts supplied, plus hydrotreated solvent grades. We report full PONA, benzene and catalyst poison figures rather than distillation and density alone.
Full Documentation
CoA with full PONA, sulphur, benzene, mercury and arsenic; SDS for the specific cut; UN 1268 transport documentation; written confirmation of the applicable CAS and REACH registration; and destination-market documentation.
Logistics Support
Experienced in bulk volatile hydrocarbon logistics — vessel, ISO tank and road tanker with vapour control and correct packing group declaration, for Indian and international delivery.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Confirm the CAS number for the specific cut in writing. Naphtha is a UVCB and light straight-run, heavy straight-run, full-range, hydrotreated and solvent grades each carry different registry numbers — carrying one across from another cargo is a documentation failure.
- Specify PONA, not just distillation and density. Two cargoes with identical boiling ranges can be worth very different amounts depending on whether the buyer is cracking or reforming.
- Report benzene content and treat it as a health specification, not just a quality one. At or above 0.1 per cent it drives a Category 1B carcinogen classification for the whole cut.
- Report n-hexane content for any solvent or adhesive application. Only the straight-chain isomer causes peripheral neuropathy, and that figure cannot be inferred from the total C6 content.
- Control mercury and arsenic to parts per billion for reformer feed. Both are permanent catalyst poisons and a single contaminated cargo can cost a catalyst charge.
- Treat all transfers as a static ignition hazard. Light naphtha flashes below −20 °C, so ignitable vapour is present at every ambient temperature, and the liquid has very low conductivity.
- Manage vapour on loading and discharge. Naphtha loading generates substantial hydrocarbon vapour, and vapour balancing or recovery is normally required both for safety and for emissions compliance.
- Bond, earth and avoid splash filling, and allow relaxation time before gauging or sampling a freshly filled tank.
- Never siphon by mouth and treat ingestion as an aspiration risk — naphtha drawn into the lungs causes severe chemical pneumonitis.
Hazard Summary
Classification: Flam. Liq. 2 (H225), Asp. Tox. 1 (H304), Skin Irrit. 2 (H315), STOT SE 3 (H336) and hazardous to the aquatic environment. Where benzene content is at or above 0.1 per cent, Carc. 1B (H350) and Muta. 1B (H340) also apply. The classification therefore depends on the composition of the specific cut.
Identity is the documentation risk: as a UVCB, naphtha is defined by its process and boiling range rather than by a structure, and several CAS numbers cover material sold under the name. REACH registration, customs classification and transport documentation all depend on matching the supplier's registration for the actual cut.
Benzene: a Category 1A human carcinogen present in most straight-run naphtha at some level. It drives the classification of the whole cut, and solvent grades intended for open handling are dearomatised specifically to remove it.
n-Hexane: naphtha in the C6 range contains n-hexane, which is metabolised to a peripheral neurotoxin. Solvent and adhesive applications with hand contact or poor ventilation should treat this as a specific hazard rather than a general hydrocarbon exposure, and co-exposure with ketone solvents makes it considerably worse.
Aspiration: low viscosity and high volatility mean a small quantity entering the lungs spreads rapidly and causes severe chemical pneumonitis. Vomiting must not be induced.
Flammability: light cuts flash below −20 °C with vapour heavier than air. Vapour clouds from loading, tank breathing and spills are the realistic incident scenario.
Catalyst poisons: mercury and arsenic at parts-per-billion level are the commercial hazard rather than the health one, permanently deactivating reformer catalyst.
PPE minimum: chemical goggles, hydrocarbon-resistant gloves, antistatic clothing and footwear at transfer points, with respiratory protection where vapour cannot be controlled.
Consult the safety data sheet for the specific cut supplied — classification varies with composition and a generic naphtha SDS may understate the hazard.
Frequently Asked Questions
Technical and commercial questions about Naphtha sourcing and specifications.
What is naphtha used for?
Steam cracking is the largest petrochemical use, converting naphtha to ethylene, propylene, butadiene and pyrolysis gasoline. Catalytic reforming is the other major route, producing benzene, toluene and xylenes along with high-octane reformate and hydrogen. Light naphtha and isomerate go into gasoline blending. Hydrotreated and dearomatised cuts are sold as industrial solvents, and naphtha is also steam reformed to synthesis gas for ammonia where natural gas is not available.
What is the difference between light and heavy naphtha?
Boiling range, and with it composition and destination. Light naphtha boils from around 30 to 90 °C and is dominated by C5 and C6 paraffins, which makes it good steam cracker feed and a gasoline blending component. Heavy naphtha boils from around 90 to 200 °C, spans C7 to C10, and contains a higher proportion of naphthenes and aromatics, which makes it the natural feed for a catalytic reformer. A full-range naphtha covers both and is normally split before use. The distinction matters commercially because the two are priced against different downstream markets.
Why does PONA matter so much?
Because the two main consumers want opposite compositions. In a steam cracker, paraffins crack cleanly to light olefins, so a paraffinic naphtha gives the highest ethylene and propylene yield. Naphthenes and aromatics give lower olefin yield and more pyrolysis gasoline and fuel oil, which are worth less. In a catalytic reformer the logic inverts: naphthenes dehydrogenate directly to aromatics in the most favourable reaction available, so naphthenic feed gives the best aromatics and octane yield, while paraffins have to be cyclised first and crack more readily to light gas. So the same boiling range can be premium feed or mediocre feed depending on which unit it is going to, and PONA is how that is measured.
Why does the CAS number vary?
Because naphtha is a UVCB — a substance of unknown or variable composition — defined by the refinery process that produced it and the boiling range it occupies, not by a molecular structure. Light straight-run naphtha, heavy straight-run naphtha, full-range naphtha, hydrotreated naphtha and dearomatised solvent naphtha each have their own registry numbers, and there are more besides for hydrocracked and catalytically cracked streams. CAS 8030-30-6 is a broad naphtha entry frequently quoted, but it may not be the number under which a specific cargo is registered. Since REACH registration, customs classification and transport documentation all reference it, it should be confirmed against the supplier's own registration for the material being shipped.
What health classification applies to naphtha?
It depends on what is in it, which is the unusual feature. The base classification covers flammability, aspiration hazard, skin irritation and central nervous system effects. But if benzene is present at 0.1 per cent or above, the whole cut is classified as a Category 1B carcinogen and mutagen, because benzene is a known human carcinogen. Separately, the n-hexane in C6-range material carries the peripheral neurotoxicity concern specific to that isomer, which matters for solvent and adhesive applications rather than closed-system cracker feed. Both figures should be on the certificate, and a solvent grade intended for open handling should be dearomatised and, where possible, low in n-hexane.
What documentation does Chelora provide?
Every cargo includes a Certificate of Analysis covering distillation, density, full PONA breakdown, olefins, total sulphur, benzene, n-hexane where relevant, mercury, arsenic, chloride, Reid vapour pressure, doctor test and copper corrosion; a Safety Data Sheet for the specific cut with classification reflecting actual composition; UN 1268 Class 3 dangerous goods documentation with the correct packing group; written confirmation of the applicable CAS and REACH registration; an origin certificate; and destination-market documentation.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Naphtha grade, volume, logistics, documentation, and lead times. We respond within one business day.
