Para Nitrophenol
Put a nitro group para to a phenolic hydroxyl and two things happen at once. The phenol becomes far more acidic than ordinary phenol, because the resulting anion is stabilised straight through the ring onto the nitro group. And the nitro group itself becomes a handle for reduction. Between those two properties sits most of the industrial chemistry of para nitrophenol — including the route to p-aminophenol and onward to paracetamol.
Chelora Chemicals supplies para nitrophenol to pharmaceutical chain customers, dye and agrochemical producers, leather chemical manufacturers and laboratories worldwide, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 100-02-7
- IUPAC name
- 4-Nitrophenol
- Molecular formula
- C6H5NO3
- Molecular weight
- 139.11 g/mol
- EC / EINECS
- 202-811-7
- UN Number
- 1663 · Class 6.1
- SMILES
- Oc1ccc(cc1)[N+](=O)[O-]
- HS Code
- 2908 99*
* Confirm the exact HS heading with your customs broker — nitrated phenol derivatives can sit under a different subheading from the nitrated hydrocarbons depending on the destination tariff schedule.
What Para Nitrophenol is used for
Para nitrophenol is a pale yellow crystalline solid melting around 114 °C. Unlike most of the nitroaromatics in this range it carries an acidic proton, and at roughly pKa 7.2 it sits close enough to physiological pH that its yellow phenolate form appears and disappears over a narrow range — which is why it has been used as a pH indicator and as the chromophore in enzyme substrate assays for decades.
Industrially, the dominant outlet is reduction to p-aminophenol, which is acetylated to paracetamol. Beyond that, the phenolate is a good nucleophile and the nitrophenyl group a convenient leaving group, so the molecule feeds agrochemical, dye, pigment and leather chemical routes as well as a steady laboratory reagent demand.
Why the para isomer behaves differently
- 4-Nitrophenol (CAS 100-02-7) — this product. No internal hydrogen bond is possible, so the molecules associate with each other: higher melting, much less volatile, more water-soluble in the salt form.
- 2-Nitrophenol (CAS 88-75-5) — an internal hydrogen bond between the nitro group and the hydroxyl makes it volatile and steam-distillable. The two separate easily for exactly this reason.
- 2,4-Dinitrophenol (CAS 51-28-5) — a second nitro group makes it far more acidic again, and far more hazardous. A different material with different controls.
- Ortho nitroanisole (CAS 91-23-6) — the methyl ether rather than the free phenol. See that page.
Appearance and handling character
The material ships as a pale yellow to yellow crystalline solid or flake, sparingly soluble in cold water but readily soluble in alkali as the phenolate, and soluble in alcohol, acetone and chloroform. It is harmful by all three exposure routes, causes serious eye damage, and is a methaemoglobin former on significant exposure. It also cakes if left open, so partial packs should be resealed.
| Parameter | Typical value |
|---|---|
| Appearance | Pale yellow crystalline solid / flake |
| Assay | 99.0% min |
| Melting range | 112 – 114 °C |
| Ortho isomer | Reported per batch |
| Dinitrophenol content | Reported per batch |
| Moisture / ash | Reported per batch |
Important: the figures above are indicative of commercial grade material and are offered for planning only. The batch certificate of analysis is the governing document. Where the material feeds a pharmaceutical chain, the related-substance profile and a metals figure usually matter more than the headline assay — send us the downstream specification and we will quote against it.
| Property | Value |
|---|---|
| Physical state | Crystalline solid at ambient |
| Melting point | ≈ 113 – 114 °C |
| Boiling point | ≈ 279 °C (with decomposition) |
| pKa | ≈ 7.15 (25 °C) |
| Relative density | ≈ 1.27 (solid) |
| Water solubility | Sparingly soluble; readily soluble in alkali |
| Organic solubility | Soluble in alcohol, acetone, chloroform |
| Appearance in alkali | Deep yellow phenolate |
Physical constants compiled from public reference data for CAS 100-02-7 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
An acidic phenol and a reducible nitro group on the same small ring give this material an unusually broad set of outlets for a nitroaromatic.
p-Aminophenol & paracetamol chain
Reduction of the nitro group gives p-aminophenol, which is acetylated to paracetamol. This is the largest single outlet for the molecule and the one with the tightest documentation requirements.
- Catalytic reduction route
- Related-substance profile is critical
- Source locked after qualification
Agrochemical intermediates
The phenolate is a good nucleophile and the nitrophenyl ester a recognised structural motif, so para nitrophenol appears across several agrochemical synthesis routes.
- End-use declaration required
- Custom synthesis quantities available
- We check destination controls first
Dye & pigment chemistry
Both the nitrophenol itself and the aminophenol derived from it feed azo dye and pigment routes, where a phenolic coupling component with a para substituent is required.
- Phenolic coupling components
- Colour limits specified on request
- See our dye intermediate range
Leather & specialty chemicals
Nitrophenol chemistry has a long-standing place in leather processing and in specialty formulations where a controlled phenolic acidity or a yellow chromophore is wanted.
- Leather chemical formulations
- Specialty intermediate use
- Technical desk review of your application
Analytical & biochemical reagent
The yellow phenolate released on hydrolysis makes nitrophenyl esters and phosphates the classic substrates for enzyme activity assays, and the free phenol a long-serving pH indicator.
- Reagent-grade material on request
- Small DG-compliant packs
- Full analytical documentation available
Contract & scheduled supply
Pharmaceutical chain buyers in particular need continuity of source, not just continuity of supply. We hold contracted tonnage from a qualified plant and release it against your production calendar.
- Annual contracts with scheduled call-off
- Source locked after qualification
- Second source held in reserve
How we supply Para Nitrophenol
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. On a molecule that feeds both a pharmaceutical chain and an agrochemical chain, that independence matters: we route your order to the plant whose impurity profile and documentation match your downstream use rather than to whichever unit we happen to own.
We place your order with whichever qualified producer best matches your assay, your related-substance limits, your price point and your delivery window.
We keep a second qualified source on this line — and where you have qualified a source for a regulated chain, we lock it rather than quietly switching.
- Downstream use read first. Pharmaceutical chain, agrochemical route or reagent use need different specifications. We ask before quoting rather than selling one grade to everyone.
- Source locked once qualified. If your dossier names a plant, we do not substitute silently — you are told before anything changes.
- Batch COA shared before dispatch. You approve assay, melting range and related substances against your own spec while the material is still in our warehouse.
- Moisture protected in packing. The product cakes if it picks up water, so we specify lined, sealed packing rather than whatever is cheapest on the day.
- Pre-shipment samples for qualification. New account or new source, your laboratory runs a trial before the full quantity ever moves.
- Export machinery handled in-house. UN 1663 classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
Packed the way your plant receives it
Pack format drives your landed cost and your handling effort — and on a solid that cakes with moisture, it also drives whether the material charges cleanly.
UN bags / fibre drums
Lined, UN-approved 25 kg packs — the standard commercial format and the easiest for manual charging without caking problems.
HDPE drums
Sealed drums with inner liner for longer storage or humid destinations, where moisture ingress through a bag seam is a genuine risk.
Jumbo bags
Where volumes and mechanical handling allow, bulk bags cut packing cost per kilo significantly — subject to the dangerous-goods position for your destination.
Samples & trial packs
Laboratory and pilot quantities dispatched so your R&D or QC team can qualify the grade first — subject to DG rules for your destination and courier.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with DG documentation filed before the booking is made rather than chased afterwards.
Campaign despatch
We hold contracted tonnage from a qualified plant and release it against your production calendar instead of landing it all at once.
Harmful by all routes, and a methaemoglobin former
Para nitrophenol is harmful by the oral, dermal and inhalation routes, causes serious eye damage, and can cause organ damage through prolonged or repeated exposure. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document and should govern your risk assessment, PPE selection, exposure monitoring and emergency planning.
Classified hazards
H302Harmful if swallowed.H312Harmful in contact with skin.H332Harmful if inhaled.H318Causes serious eye damage.H373May cause damage to organs through prolonged or repeated exposure.H411Toxic to aquatic life with long lasting effects.
Hazard statements reflect classifications commonly published for CAS 100-02-7. Some suppliers list skin irritation and additional organ-toxicity entries. Always read the SDS issued with your specific batch — and note that nitrophenols are methaemoglobin formers, which shapes both your controls and your first-aid plan.
Spill & emergency orientation
Plan your response before the pallet arrives. Sections 4, 5 and 6 of the SDS are the authoritative instructions and should be posted at the point of use.
- Contain, do not hose to drain. H411 applies, and the phenolate dissolves readily in alkaline water — collect spilled solid mechanically and avoid washing it anywhere.
- Avoid raising dust. Fines are the main inhalation route on a crystalline solid. Sweep damp or vacuum with suitable filtration rather than brushing dry.
- Expect delayed presentation. Methaemoglobinaemia may appear some time after exposure. A casualty who feels fine should still be assessed, with the SDS in hand.
- Eye exposure is urgent. H318 means serious, potentially irreversible damage — irrigation must start immediately and continue en route to medical care.
- Segregate from strong bases, reducing agents and oxidisers in storage as well as in process.
Storage
- Cool, dry, well-ventilated and access-controlled store, out of direct sunlight and away from heat sources.
- Reseal partial packs. The material picks up moisture and cakes, which turns a clean charging operation into one that generates dust and frustration.
- Segregate from strong bases — contact forms the phenolate and discolours the material — and from reducing agents and oxidisers.
- Sealed and bunded floor. Aquatic toxicity means spill containment is a control measure, not an administrative nicety.
- Shelf life is typically 24 months or more in sealed original packing. Re-assay before use after long storage.
Handling & PPE
- Control dust first. Closed charging, local exhaust ventilation and low-dust handling practices do more than PPE ever will on a crystalline solid.
- Eye protection is not optional. With a serious-eye-damage classification, goggles rather than spectacles, and an accessible eyewash station.
- Chemical-resistant gloves and coveralls, with contaminated clothing removed and washed before reuse.
- Respiratory protection during pack opening, charging and any operation that can generate airborne fines, per your own exposure assessment.
- Never discharge to drain or watercourse. Contain and dispose of as regulated chemical waste.
Transport
Nitrophenols move as regulated cargo under UN 1663, Class 6.1. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The applicable packing group is stated on your shipping documents and SDS — ask us for the current DG paperwork when you plan the shipment.
What travels with every consignment
A chemical shipment is only as good as the file that travels with it — and on a pharmaceutical chain intermediate, the file is half the product.
Certificate of Analysis
Batch-specific assay, melting range, ortho isomer and dinitrophenol content, moisture and ash — checked against your purchase specification before we release the goods.
GHS Safety Data Sheet
Full 16-section SDS in GHS format covering hazards, exposure controls, handling, storage, spill response, toxicology and disposal — issued in the language your destination requires.
Dangerous Goods Declaration
UN 1663, hazard class, packing group and IMDG or IATA declaration prepared and filed before the container is booked, with correctly marked and labelled packaging.
Certificate of Origin
Chamber-attested where required, plus preferential-origin forms where a trade agreement gives your import duty relief at the destination.
Third-party inspection
SGS, Intertek or Bureau Veritas sampling and inspection arranged on request before loading, giving you independent verification of what actually ships.
Retained & pre-shipment samples
Pre-shipment samples carry the same COA as the commercial lot, so what your laboratory qualifies is exactly what arrives. Retention samples held against the batch.
An acidic phenol and a reducible nitro group
Two functional groups, each useful on its own, on a ring small enough that they influence each other strongly. The routes below are the general industrial pattern, not a process disclosure.
Nitrate or substitute
Commercial material is reached either by controlled nitration of phenol or by hydrolysis of an activated para-nitrochlorobenzene, depending on the plant.
Separate from the ortho isomer
The ortho isomer is volatile and steam-distillable because of its internal hydrogen bond; the para isomer is not. That difference does most of the separation work.
Reduce to the aminophenol
Catalytic reduction converts the nitro group to an amine, giving p-aminophenol — the step that carries the pharmaceutical chain.
Acylate, couple or esterify
From there the molecule is acetylated to the finished active, coupled into a dye, or esterified into a nitrophenyl substrate for analytical use.
Why feed quality carries through the whole route
On a pharmaceutical chain in particular, what arrives in the bag is what your regulator eventually asks about:
- Ortho isomer reduces to the ortho aminophenol — a related substance that has to be removed downstream or explained in a dossier.
- Dinitrophenol content is both a quality and a safety matter: it is a far more hazardous material in its own right and must be controlled at low levels.
- Metals and ash affect catalyst performance in the reduction step and carry into the related-substance profile of the finished product.
- Moisture causes caking in the pack and complicates accurate charging, quite apart from any effect on the reaction.
That is why we ask what the material feeds before quoting, and why the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Intermediate | Principal character |
|---|---|
| Para nitrophenol CAS 100-02-7 — this product | Acidic phenol Route to p-aminophenol |
| Ortho nitroanisole CAS 91-23-6 | Methyl ether, not free phenol Route to o-anisidine |
| 2,4-Dinitrochlorobenzene CAS 97-00-7 | Activated chlorine Substitution substrate |
We supply across the nitro aromatic range — see the full intermediate range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this intermediate
Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Paracetamol demand sets the tone
The analgesic chain is large enough that its buying patterns move the whole market. When paracetamol demand spikes, merchant nitrophenol tightens quickly and lead times move before prices do.
- Quote early for campaign tonnage
- Health-season demand is seasonal but sharp
- Contracted call-off smooths the exposure
Upstream feedstock
Depending on the plant, the route runs back through phenol or through chlorobenzene and nitration. Benzene, phenol and acid economics all feed through within a quarter or so.
- Two routes, two cost structures
- Energy cost weighs on crystallisation
- We flag feedstock-driven moves in the quote
Documentation requirement
Material destined for a pharmaceutical chain costs more than the same molecule destined for a dye vat — not because it is purer by magic, but because the plant carries the documentation and audit burden.
- Tell us the end use before comparing offers
- A cheaper quote may be a different grade
- We state which grade we are quoting
Regulatory pressure
Nitrophenol production carries effluent and emissions obligations, and the agrochemical end use attracts additional scrutiny in some destinations. Both sit inside the price.
- End-use declarations in some markets
- Effluent rules shape plant economics
- We check destination rules before quoting
Freight & DG surcharges
Class 6.1 cargo carries a hazardous surcharge and space is tighter than for general cargo. Destination and Incoterm move landed cost as much as the ex-works price does.
- Compare on landed cost, not ex-works
- DG space books out ahead of peak season
- We quote FOB, CIF, CFR or DDP as you prefer
Source availability
A plant turnaround, an environmental inspection or a monsoon disruption can take capacity offline at short notice. Buyers locked to a single qualified source feel this hardest.
- We hold a second qualified source on this line
- Qualify the alternate before you need it
- Ask us about dual-source contracts
| If your end use is… | Specify |
|---|---|
| Pharmaceutical chain | Tight related substances; metals reported; source locked |
| Agrochemical route | Consistent assay; end-use declaration provided |
| Dye & pigment synthesis | Colour limit; low dinitrophenol content |
| Leather & specialty | Standard commercial grade; moisture controlled |
| Analytical / reagent | Highest available purity, small DG-compliant pack |
Not sure which column you are in? Describe what the material feeds and our technical desk will recommend the grade — including telling you when a cheaper specification would do the job just as well.
Support that goes beyond shipping the drum
What our technical desk will do
- Ask what it feeds before quoting. A pharmaceutical chain and a dye vat need different grades, and quoting one price for both serves nobody.
- Support your dossier. Where the material feeds a regulated chain, we work with you on the identity, purity and impurity documentation required, and lock the source after qualification.
- Be straight about the hazard profile. Harmful by all routes, serious eye damage, methaemoglobin formation — stated at enquiry stage so your EHS team can plan.
- Review your specification before it goes into a contract, so you are not locked into a limit that no plant can consistently hit.
Regulatory & compliance notes
- End-use declarations. Some destinations require a statement of intended use where a nitrophenol could feed pesticide manufacture. We check before quoting, not after you have raised the PO.
- Import controls vary by destination. Nitrophenols attract notification requirements in several jurisdictions.
- Chemical inventory listings differ between regions — we will supply the identity data you need for that filing.
- Effluent and waste rules matter because of the aquatic classification. Check your discharge consent against the material before introducing it.
None of the above is legal advice — your own regulatory affairs team owns the final compliance position for your import and your workplace. What we commit to is accurate product identity data, an honest statement of the hazard classification and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Product name or CAS 100-02-7, the assay and related-substance limits you work to, what the material feeds, quantity, pack preference and destination port.
Receive a firm quote
Pricing, lead time, packing and Incoterm confirmed in writing within 24 hours — our sourcing desk is staffed around the clock.
Qualify and approve
Sample dispatched if you are qualifying a new source. Batch COA shared for your approval before the material is released.
Ship and track
UN 1663 classification filed, DG freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
Others in the Chelora range
What buyers ask us about Para Nitrophenol
Can you supply pharma-chain grade?
How is this different from the ortho isomer?
What purity do you normally supply?
Why does the material look darker in some batches?
What is the minimum order quantity?
How long does delivery take?
How should we store it, and what is the shelf life?
Is this a dangerous good? What paperwork comes with it?
- Batch certificate of analysis
- GHS-format safety data sheet
- Dangerous-goods declaration with UN number, class and packing group
- Commercial invoice, packing list and bill of lading or airway bill
- Certificate of origin and any destination-specific forms
Do you supply to my country?
Do you manufacture this yourself?
Request pricing on Para Nitrophenol
Send your required assay, related-substance limits, what the material feeds, quantity, pack format and destination port. Our sourcing desk is available 24 hours a day, 7 days a week, and comes back with pricing, lead time and packing options — whether that is a single trial pack or a contracted programme for the year.