Nitrobenzene CAS 98-95-3

What is Nitrobenzene?

Nitrobenzene is the simplest aromatic nitro compound, formula C₆H₅NO₂, formed by nitrating benzene. At room temperature it is a pale yellow, oily liquid with a distinctive almond-like odour, melting around 5.7 °C and only slightly soluble in water.

Its overwhelming commercial importance is as the feedstock for aniline: roughly 95–98% of all nitrobenzene produced is immediately hydrogenated to aniline in the same or an adjacent plant, almost always within a closed, continuous system. Aniline in turn is the single largest building block for MDI and other isocyanates used in polyurethane manufacture, which is why nitrobenzene production tracks the polyurethane industry's growth more closely than any other market.

Commercially, nitrobenzene is produced by nitrating benzene with mixed nitric and sulfuric acid in a continuous process, then reduced on-site to aniline wherever possible, since nitrobenzene itself is rarely held or shipped in large standalone volumes except for merchant intermediate and specialty use.

Nitrobenzene is a regulated toxic chemical: it is absorbed readily through the skin, causes methemoglobinemia on acute exposure, and is reasonably anticipated to be a human carcinogen by the US National Toxicology Program, which shapes how it must be handled, stored and documented.

Why Nitrobenzene specifically

• The direct precursor to aniline. Catalytic hydrogenation of the nitro group gives aniline cleanly and at scale, underpinning the entire polyurethane value chain.
• A mild, selective oxidant. Nitrobenzene is used stoichiometrically in reactions such as the Skraup quinoline synthesis, where it oxidises an intermediate without over-oxidising the product.
• A solvent and reaction medium. Its polarity and inertness under certain conditions make it useful as a solvent in petroleum refining and in Friedel-Crafts reactions, where it helps hold the catalyst in solution.
• A route to other substituted nitrobenzenes. Further nitration, halogenation or sulfonation of nitrobenzene gives a range of other nitroaromatic intermediates used across the dye and agrochemical industries.

How Nitrobenzene is Manufactured

Nitrobenzene is made on purpose by nitrating benzene, in a process that has been refined for scale and continuous operation for over a century.

• Nitration of benzene. Benzene is reacted with a mixed nitric acid / sulfuric acid stream under controlled temperature, substituting a nitro group onto the ring.
• Quenching and separation. The reaction mass is quenched, and the crude nitrobenzene oil is separated from the spent acid phase.
• Acid recovery. Spent sulfuric acid is typically reconcentrated and recycled back into the nitration step, a key economic feature of modern plants.
• Washing and purification. The crude nitrobenzene is washed to remove residual acid and purified by distillation to commercial purity.
• On-site hydrogenation (where applicable). At most integrated sites, the purified nitrobenzene is fed directly into a catalytic hydrogenation unit to produce aniline, minimising the volume held or shipped as nitrobenzene itself.

Typical Commercial Specification

Figures below are representative of commercial-grade Nitrobenzene. Tell us your downstream route and the grade you need, and we will advise on the specification to order against.

Physical & Chemical Properties

Behaviour in the process

Nitrobenzene's reactivity pattern is what makes it so central to downstream chemistry:

• Clean reduction to aniline. Catalytic hydrogenation reduces the nitro group cleanly, which is the basis of the entire aniline industry.
• Selective reduction intermediates. Partial reduction gives azoxybenzene, azobenzene, nitrosobenzene and phenylhydroxylamine, each with its own downstream chemistry.
• Mild oxidant. In reactions such as the Skraup quinoline synthesis, nitrobenzene is reduced in turn, oxidising the other reactant without the harsher side reactions a stronger oxidant would cause.
• Reactive combustion hazard. It reacts violently with a range of common materials (aluminium chloride with phenol present, strong bases, certain metal salts), so segregation is a real operational requirement, not a formality.

Nitrobenzene and Related Nitroaromatics

Nitrobenzene is the parent nitroaromatic, and buyers often need to distinguish it from its substituted relatives.

Stated plainly: nitrobenzene is a feedstock, not a finished intermediate for most buyers — the overwhelming majority of demand is for the aniline it becomes, and the substituted nitrobenzenes above serve entirely separate downstream chemistries.

Industries We Supply Nitrobenzene To

The same liquid feeds an aniline/polyurethane value chain, a dye-intermediate works and a specialty-solvent user. What changes is the scale and the documentation each requires.

Where Nitrobenzene is Used

Nitrobenzene is bought overwhelmingly to become aniline, with a long tail of smaller specialty uses behind it. These are the end uses our customers buy it for.

In aniline manufacture

Nitrobenzene is catalytically hydrogenated to aniline, almost always in a continuous, closed process integrated with the nitration step. Purity and residual acidity both affect catalyst life and conversion efficiency, which is why they are specified tightly even for merchant material destined for this route.

In dye, rubber-chemical and specialty synthesis

Outside the aniline route, nitrobenzene and its further-substituted derivatives feed azo dye synthesis, rubber accelerator and antioxidant chemistry, and selected specialty syntheses where its reactivity as a mild, selective oxidant is the property being bought.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis, with acidity and moisture reported alongside purity because both affect downstream hydrogenation and handling.

• Nitrobenzene content — by gas chromatography, the primary grade measure.
• Dinitrobenzene — reported as an over-nitration impurity.
• Residual benzene — checked as an unreacted-feedstock impurity.
• Acidity (as H₂SO₄) — tested because residual acid affects catalyst life and equipment corrosion.
• Moisture — measured to limits relevant to downstream reaction and storage stability.
• Colour (Hazen / APHA) — an indicator of thermal history and trace contamination.

Common Process Problems & Likely Causes

When nitrobenzene causes trouble, it is usually residual acid, moisture or dinitrobenzene carry-over. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. Drums and ISO tank containers for liquid, rated for Class 6.1 toxic-goods transport.
• Material compatibility. Use equipment and containers rated for nitroaromatic liquids; avoid aluminium and other reactive metals in contact with concentrated material.
• Temperature control. Store above its melting point (about 5.7 °C) and away from direct sun and heat sources; flash point is about 88 °C.
• Segregation. Keep strictly apart from strong oxidisers, strong bases, aluminium chloride, and aniline/glycerol mixtures.
• Shelf life. Stable in sealed, dry containers; moisture ingress and prolonged light exposure are the main degradation routes.
• Transport classification. UN 1662, nitrobenzene, Class 6.1 (toxic). ADR, IMDG, IATA and DOT requirements apply to tank design, labelling and routing.

Hazards & Safe Handling

Nitrobenzene is toxic by all routes of exposure, readily absorbed through the skin, and causes methemoglobinemia on acute exposure. It is also reasonably anticipated to be a human carcinogen, which makes closed handling and exposure monitoring central to safe use.

• Toxicity and methemoglobinemia. Acute exposure by inhalation, ingestion or skin contact causes methemoglobinemia; symptoms include fatigue, weakness, dyspnoea and headache.
• Skin absorption. Nitrobenzene is readily absorbed through intact skin. Impermeable gloves and clothing are required.
• Occupational exposure limits. The odour threshold (about 0.018 ppm) is well below hazardous levels, so odour is not a reliable warning; the threshold limit value is about 5 mg/m³ (1 ppm). Confirm the limit applicable in your jurisdiction.
• Ethanol interaction. Ethyl alcohol consumption aggravates the toxic effects of nitrobenzene exposure; this is a specific, documented interaction worth including in worker training.
• Combustibility. A combustible liquid; avoid ignition sources near bulk storage and transfer points.
• PPE. Chemical-resistant gloves, goggles or a face shield, and respiratory protection appropriate to vapour exposure.
• Environment. Not generally considered harmful to aquatic life at typical exposure levels but should not be released to waterways; follow local effluent rules.

Regulatory & Compliance Notes

Nitrobenzene is a regulated toxic chemical with specific occupational and transport rules. Because obligations differ by territory and use, the notes below are orientation rather than legal advice — confirm your own position with your regulatory adviser.

• GHS classification. Typically classified as acutely toxic and a suspected carcinogen; the SDS carries the full hazard statements for your grade.
• Carcinogen listings. Listed by the US NTP as reasonably anticipated to be a human carcinogen; EPA has separately classified it under its own weight-of-evidence category. Confirm the applicable listing in your jurisdiction.
• Occupational exposure regulation. Many jurisdictions apply skin-notated exposure limits and require medical surveillance for workers with regular exposure.
• REACH and chemical inventories. Registered under EU REACH and listed on major chemical inventories.
• Dangerous goods transport. UN 1662, Class 6.1 (toxic). ADR, IMDG, IATA and DOT requirements apply to tank design, labelling and routing.
• Quality agreements. Aniline and dye-intermediate producers commonly expect documented acidity, moisture and colour limits and change control. Tell us what your agreement requires.

We Supply Nitrobenzene Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Nitrobenzene from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, toxic-goods paperwork and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged where toxic-goods rules and routing allow.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and the Class 6.1 transport declaration issued as a complete set.
• Flexible volumes. From drum quantities up to full ISO tank loads on contract supply.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying Nitrobenzene from Chelora

We are an independent sourcing and supply partner. For nitrobenzene that means settling three things at enquiry: the purity your process needs, the packing format you can receive, and the toxic-goods documentation that moves it legally across your shipping lane.

• Documentation on every lot. Batch-specific COA with purity, acidity and colour, plus SDS and Class 6.1 transport paperwork.
• Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
• Quantities. Drum quantities through to full ISO tank loads on contract supply.
• Inspection. Independent third-party inspection available at loading when the contract requires it.
• Related intermediates. Aniline, PNCB and ONCB alongside nitrobenzene from one supplier.

How ordering works

• Send the enquiry. Purity, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing format and a sample COA, normally within one working day.
• Qualify the supply. For first orders or critical applications, we share the analysis so your technical team can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Allocation and QC. Material allocated and released against a batch-specific COA, with an independent inspection where the contract calls for it.
• Ship and document. Filled, labelled and loaded with the full export and Class 6.1 transport document set, and tracked through to arrival.

Related Nitroaromatics & Aniline Intermediates

Buyers of nitrobenzene often source aniline itself or the substituted nitrochlorobenzenes alongside it. Consolidating them cuts freight cost and gives you a single point of contact for documentation.