Urea
The densest practical way to carry nitrogen: 46% N in a stable white solid. Fertiliser first, but also the feedstock for melamine, UF resins and diesel exhaust fluid.
Molecular Structure
What is Urea?
Urea is a carbonyl group flanked by two amine groups. At 60.06 g/mol with two nitrogens, it carries 46.6% nitrogen by mass — the highest nitrogen content of any solid fertiliser in common use, which is what makes it economic to ship around the world.
The molecule is planar, which is not what you would expect from two sp³ amines. Both nitrogen lone pairs delocalise into the carbonyl, flattening the whole structure and lengthening the C=O bond. That same delocalisation makes urea unusually stable and highly soluble in water, and it is why urea is a neutral solid rather than a reactive amine.
It is made by reacting ammonia with carbon dioxide under pressure to form ammonium carbamate, which is then dehydrated to urea. Because the CO₂ generally comes from the same ammonia plant's reforming section, urea plants are almost always built alongside ammonia plants.
Chelora supplies prilled and granular urea in fertiliser, technical and DEF/AdBlue grades. Biuret is the specification that separates them — technical and DEF grades require tighter limits than agricultural material, and we certify biuret on every consignment.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
Urea is more delocalised than it looks. Both amine lone pairs feed into the carbonyl, which flattens the molecule, stabilises it, and sets up the extensive hydrogen bonding behind its solubility and its resin chemistry.
Structure — planar, with both N lone pairs conjugated to C=O
Structural Identity
- IUPAC NameUrea
- Common namesCarbamide, carbonyl diamide
- Molecular FormulaCH₄N₂O
- Molecular Weight60.06 g/mol
- Nitrogen content46.6% by mass
- GeometryPlanar — N lone pairs conjugated
- C=O bond length1.26 Å — lengthened by resonance
- Solubility in water≈ 1080 g/L at 20 °C
- Key impurityBiuret, from thermal condensation
- CAS Number57-13-6
- InChI KeyXSQUKJJJFZCRTK-UHFFFAOYSA-N
Product Specifications
Chelora supplies Urea in standard and custom grades. Contact us for specification sheets tailored to your process.
| Chemical name | Urea (carbamide) |
|---|---|
| CAS Number | 57-13-6 |
| Molecular formula | CH₄N₂O |
| Molecular weight | 60.06 g/mol |
| Nitrogen content (min) | ≥ 46.0 wt% |
| Biuret — fertiliser grade (max) | ≤ 1.0 wt% |
| Biuret — technical grade (max) | ≤ 0.9 wt% |
| Biuret — DEF / AdBlue grade (max) | ≤ 0.3 wt% |
| Moisture (max) | ≤ 0.5 wt% (prilled), ≤ 0.3 (granular) |
| Free ammonia (max) | ≤ 150 ppm wt |
| Formaldehyde anti-caking agent | ≤ 0.55 wt% (where applied) |
| Iron (max) | ≤ 1.0 ppm wt |
| Heavy metals as Pb (max) | ≤ 1.0 ppm wt |
| Insolubles (max) | ≤ 20 ppm wt |
| Particle size — prilled | 1.0 – 2.4 mm, ≥ 90% |
| Particle size — granular | 2.0 – 4.0 mm, ≥ 90% |
| Crushing strength — granular | ≥ 3.0 kgf |
| Appearance | White, free-flowing prills or granules |
| Melting point | 132.7 °C (with decomposition) |
| Transport classification | Not regulated as dangerous goods |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Urea.
Nitrogen Fertiliser
The dominant outlet, taking around four-fifths of world production. Soil urease hydrolyses it to ammonium, making nitrogen available to the crop; granular grades suit bulk spreading, prilled grades blending.
UF Resins & Wood Panels
Condensed with formaldehyde into urea-formaldehyde resin, the principal adhesive for particleboard, MDF and interior plywood, and for moulding compounds.
Melamine
Thermal conversion at pressure gives melamine, which goes back to formaldehyde for melamine-formaldehyde resins — durable laminate surfaces, tableware and coatings.
Diesel Exhaust Fluid
A 32.5% aqueous solution of low-biuret urea is AdBlue/DEF, injected into SCR systems to reduce NOx in diesel exhaust. Purity requirements under ISO 22241 are far tighter than fertiliser grade.
Animal Feed
A non-protein nitrogen source for ruminants, whose rumen microbes convert it to microbial protein. Inclusion rates are tightly limited because excess causes ammonia toxicity.
Personal Care & Technical
A humectant and keratolytic in creams and dermatological preparations, and a technical additive in textile, adhesive and de-icing applications.
Why source Urea through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation — no grey-market supply.
Grade Flexibility
Fertiliser, technical and DEF/AdBlue grades supplied prilled or granular. Biuret, moisture and particle size specified to your application — DEF grade to ISO 22241.
Full Documentation
CoA, SDS, UN transport docs, REACH compliance, and destination-market certificates with every shipment.
Logistics Support
Experienced in bulk and bagged solid fertiliser logistics — moisture-protected bulk vessels, jumbo and 50 kg bags, and the fertiliser movement and licensing paperwork required in destination markets.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Store under cover in a dry, well-ventilated building — urea is hygroscopic and will absorb moisture from humid air, then cake into a solid mass.
- Keep bags and bulk piles off concrete floors on pallets or a moisture barrier, and avoid stacking beyond the recommended height to limit compaction caking.
- Do not store near heat sources; urea decomposes above its 132.7 °C melting point, releasing ammonia.
- Control dust at transfer and bagging points with extraction and, where needed, respiratory protection — urea dust irritates eyes and airways.
- Keep away from strong oxidisers, acids, hypochlorites and nitrites, which react with urea and with the ammonia it can release.
- Segregate DEF and technical grades from fertiliser stock and from any prior product residues — contamination in dedicated handling equipment is the usual cause of off-specification DEF.
- Prevent spillage into drains and watercourses; the nitrogen load causes eutrophication even though urea itself is low hazard.
- Check your destination market's fertiliser movement, subsidy and licensing rules before shipping — subsidised agricultural urea is frequently restricted from diversion to industrial use.
Hazard Summary
Classification: Urea has no harmonised CLP classification and is generally not classified as hazardous. Some suppliers apply Eye Irrit. 2 (H319) and STOT SE 3 (H335) for dust exposure — check the SDS for the specific grade rather than assuming it is unclassified.
Dust: The realistic occupational hazard is nuisance and irritant dust at transfer, bagging and spreading points. Control it at source; there is no substance-specific occupational exposure limit in most jurisdictions, so general inhalable dust limits apply.
Thermal decomposition: Above its melting point urea decomposes and releases ammonia, and in a fire it will also produce nitrogen oxides. Firefighters need self-contained breathing apparatus even though the material itself does not burn.
Caking: Urea is strongly hygroscopic. Moisture ingress during storage or transit causes caking that can make a consignment unusable without reprocessing, which is a commercial rather than a safety issue but a common one.
Environment: Not acutely toxic, but nitrogen release to surface water causes eutrophication. Contain spills and do not wash residues to drain.
Regulatory note: Urea is a controlled or subsidised commodity in a number of markets, including under India's Fertiliser (Control) Order, with restrictions on diverting subsidised agricultural material to industrial use. Confirm the movement, licensing and end-use rules that apply to your consignment.
PPE minimum: Safety glasses, gloves and dust protection appropriate to the handling operation; full protection is rarely needed for packaged material handled without dust generation.
Consult the full SDS for exposure limits, spill containment, emergency response, and disposal before any use.
Frequently Asked Questions
Technical and commercial questions about Urea sourcing and specifications.
What is urea used for?
About four-fifths goes to agriculture as a nitrogen fertiliser, applied directly or blended into compound formulations. The industrial balance is dominated by urea-formaldehyde resins for wood panels, melamine production, and diesel exhaust fluid for SCR systems on diesel engines. Smaller volumes go to ruminant feed as non-protein nitrogen, and to cosmetic and dermatological preparations.
Why does urea contain 46% nitrogen?
Two nitrogen atoms at 14.01 g/mol each in a molecule of 60.06 g/mol works out at 46.6% by mass. Nothing else that is stable, solid and cheap does better — ammonium nitrate is 34% and ammonium sulphate 21%. That nitrogen density is exactly why urea dominates world fertiliser trade: you are paying to ship less inert mass per unit of nitrogen delivered.
What is biuret and why is it specified?
Biuret forms when two urea molecules condense and lose ammonia, which happens if urea is held too hot for too long during production or handling. It matters because it is phytotoxic: at elevated levels it damages crops, and foliar applications and sensitive crops such as citrus are affected at lower concentrations than soil-applied material. Fertiliser grade typically allows up to 1.0%, technical grade around 0.9%, and DEF grade no more than 0.3%.
What makes DEF or AdBlue grade urea different?
DEF is a 32.5% aqueous solution of urea used in selective catalytic reduction on diesel engines, and it is made to ISO 22241. The urea must be far purer than fertiliser grade — biuret below 0.3%, very low metals, aldehydes and insolubles — because trace contaminants poison the SCR catalyst and can damage the dosing system. Anti-caking agents applied to fertiliser urea are not acceptable, and handling equipment has to be dedicated.
Why does urea cake, and how is it prevented?
Urea is hygroscopic: above a critical relative humidity of around 72–75% at 30 °C it absorbs water from the air, and when conditions dry again the dissolved surface recrystallises and bridges the particles together. Prevention is dry covered storage, moisture barriers between stock and floors, limited stack heights to reduce compaction, and where appropriate a coating or anti-caking treatment — though that treatment rules the material out for DEF.
What documentation does Chelora provide?
Every shipment includes a Certificate of Analysis covering nitrogen content, biuret, moisture, free ammonia, iron, heavy metals, insolubles and particle size distribution, with crushing strength for granular material; a Safety Data Sheet (GHS/REACH); confirmation that the material is not regulated as dangerous goods for transport; an origin certificate; and the fertiliser registration or import documentation required in the destination market.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Urea grade, volume, logistics, documentation, and lead times. We respond within one business day.
