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Linuron is a selective phenylurea herbicide developed for pre-emergence and post-emergence control of susceptible annual broadleaf weeds and grasses.
Linuron combines foliar activity with residual soil action and is absorbed through both roots and leaves.
Linuron inhibits photosynthetic electron transport at photosystem II, gradually producing chlorosis, tissue damage, growth cessation, and plant death.
Linuron is commercially encountered as technical material, suspension concentrates, wettable powders, water-dispersible granules, flowable concentrates, and analytical reference material.
CHEMICAL IDENTITY AND COMMON NAMES
Linuron is the internationally recognised common name for 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea.
Linuron belongs to the substituted urea and phenylurea classes of herbicides.
The molecule contains a 3,4-dichlorophenyl group connected to an N-methoxy-N-methylurea structure.
Linuron has no stereogenic centre and does not require isomer-specific grade designation.
Synonyms and Common Names: Linuron, Linuron ISO, Linuron ANSI, Linuron BSI, Methoxydiuron, 3-(3,4-Dichlorophenyl)-1-methoxy-1-methylurea, 3-(3,4-Dichlorophenyl)-1-methyl-1-methoxyurea, N′-(3,4-Dichlorophenyl)-N-methoxy-N-methylurea, N-(3,4-Dichlorophenyl)-N′-methoxy-N′-methylurea, N-(3,4-Dichlorophenyl)-N′-methyl-N′-methoxyurea, 1-(3,4-Dichlorophenyl)-3-methoxy-3-methylurea, 1-Methoxy-1-methyl-3-(3,4-dichlorophenyl)urea, Urea, 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl-, Urea, N′-(3,4-dichlorophenyl)-N-methoxy-N-methyl-
TECHNICAL IDENTIFICATION
CAS Number: 330-55-2
EC / EINECS Number: 206-356-5
CLP Index Number: 006-021-00-1
CIPAC Number: 76
US EPA Chemical Code: 035506
PubChem CID: 9502
UNII: 01XP1SU59O
Molecular Formula: C9H10Cl2N2O2
Molar Mass: 249.09 g/mol
Chemical Class: Substituted urea herbicide
Herbicide Family: Phenylurea
Current Global Mode-of-Action Group: Group 5
Legacy WSSA Group: Group 7
Legacy HRAC Group: Group C2
IUPAC Name: 3-(3,4-Dichlorophenyl)-1-methoxy-1-methylurea
CAS Name: N′-(3,4-Dichlorophenyl)-N-methoxy-N-methylurea
InChIKey: XKJMBINCVNINCA-UHFFFAOYSA-N
Canonical SMILES: CN(OC)C(=O)NC1=CC(=C(C=C1)Cl)Cl
Identity testing commonly combines chromatographic retention data with infrared or mass-spectrometric confirmation.
High-performance liquid chromatography is suitable for active-content determination, while sensitive gas-chromatographic methods support trace-impurity analysis.
PHYSICAL AND CHEMICAL PROPERTIES
Appearance: Colourless to white crystalline solid or crystalline powder
Physical State: Solid
Odour: Essentially odourless
Melting Point: 93–94°C
Boiling Behaviour: Decomposes before boiling
Decomposition Temperature: Approximately 220°C
Density: Approximately 1.49 g/cm3 at 20°C
Water Solubility: 63.8 mg/L at 20°C and pH 7
Solubility in Acetone: Approximately 395 g/L at 20°C
Solubility in Ethyl Acetate: Approximately 292 g/L at 20°C
Solubility in Methanol: Approximately 170 g/L at 20°C
Solubility in Toluene: Approximately 75 g/L at 20°C
Vapour Pressure: Approximately 5.1 × 10−5 Pa at 20°C
Henry’s Law Constant: Approximately 2.0 × 10−4 Pa·m3/mol at 25°C
Log Kow: Approximately 3.0 at 20°C and pH 7
Dissociation: No relevant dissociation in water
Hydrolysis Half-Life: Approximately 1,460 days at 20°C and pH 7
Hydrolytic Stability: Stable between pH 5 and pH 9 at 22°C
Soil DT50: Approximately 57.6 days under representative aerobic conditions
Soil Organic Carbon Adsorption Coefficient: Approximately 843 mL/g
Bioconcentration Factor: Approximately 49
Volatility: Low
Corrosivity: Non-corrosive in pure form
Combustibility: Combustible solid
Minimum Technical Purity: 950 g/kg
Linuron is only slightly soluble in water but has much greater solubility in several polar organic solvents.
This solubility profile favours suspension-based aqueous formulations and solvent-assisted processing rather than true aqueous concentrates.
The low vapour pressure limits volatilisation from treated plant and soil surfaces.
The moderate octanol-water partition coefficient and soil adsorption support residual soil activity while also making runoff, sediment transport, and drainage management important.
Linuron is hydrolytically stable under normal environmental pH conditions.
Transformation in soil proceeds mainly through microbial degradation, demethylation, demethoxylation, and formation of metabolites including 3,4-dichloroaniline-related products.
FUNCTIONAL CHARACTERISTICS
Linuron acts primarily by binding to the plastoquinone-binding region of the D1 protein in photosystem II.
This binding blocks electron transfer from QA to QB in chloroplast thylakoid membranes.
The interruption stops normal carbon fixation and reduces the production of ATP and reducing power required for plant growth.
Secondary oxidative damage and lipid peroxidation contribute to chlorosis, necrosis, and plant death.
Root uptake supports pre-emergence and residual performance in the soil zone occupied by germinating weeds.
Foliar uptake permits early post-emergence activity against susceptible seedlings.
Movement within plants is mainly upward through the transpiration stream.
Crop selectivity is associated with differences in uptake, translocation, metabolic detoxification, placement, growth stage, and application timing.
Adequate soil moisture supports activation and movement into the germinating weed zone after pre-emergence treatment.
Excessive rainfall or irrigation can increase movement away from the intended treatment zone and raise crop-injury, drainage, or surface-water risks.
Repeated reliance on Linuron or other Group 5 photosystem II inhibitors can select resistant weed populations.
Resistance-management programs combine different effective modes of action with crop rotation, cultivation, sanitation, competitive crop stands, and prevention of weed-seed return.
PRODUCTION AND COMMERCIAL FORM
Industrial production commonly forms the phenylurea linkage by reacting 3,4-dichlorophenyl isocyanate with N,O-dimethylhydroxylamine.
An alternative route forms a 3,4-dichlorophenyl hydroxyurea intermediate followed by controlled methylation.
Reaction control is followed by crystallisation, filtration, solvent washing, purification, and drying.
Purification is particularly important for controlling trace chlorinated aromatic impurities associated with 3,4-dichloroaniline-derived manufacturing routes.
Technical Linuron is generally produced as a white crystalline solid containing at least 950 g/kg active substance.
Technical material serves as an industrial intermediate for the production of registered end-use herbicide formulations.
Suspension concentrates disperse finely milled Linuron particles in an aqueous continuous phase containing wetting agents, dispersants, rheology modifiers, antifoams, and preservatives.
Wettable powders combine Linuron with finely divided carriers and surfactants that support wetting and suspension after addition to water.
Water-dispersible granules provide a low-dust solid form that disintegrates into suspended particles during spray-tank preparation.
Flowable concentrates provide liquid handling while retaining Linuron as suspended solid particles.
Emulsifiable concentrates and liquid suspension formulations have also been produced for particular markets and application systems.
Analytical reference materials are supplied at high purity for residue analysis, environmental monitoring, formulation control, and chromatographic calibration.
APPLICATIONS AND INDUSTRIES
Agricultural Weed Control
Linuron has been used for selective control of susceptible annual broadleaf weeds and annual grasses in registered agricultural production systems.
Current and historical crop uses include carrots, potatoes, asparagus, celery, parsnips, dry beans, peas, maize, soybeans, cotton, grain sorghum, cereals, sunflower, coffee, tea, rice, bananas, orchards, and ornamental crops.
Authorised crop lists differ substantially between jurisdictions because Linuron has undergone extensive regulatory withdrawal and use restriction.
Pre-Emergence Treatment
Linuron can be applied after planting but before weed emergence in authorised crops.
Root uptake provides residual control as susceptible weeds germinate and grow through the treated soil layer.
Soil texture, organic matter, moisture, rainfall, application placement, and crop tolerance affect residual performance and selectivity.
Post-Emergence Treatment
Linuron can control small, actively growing weeds through foliar uptake where post-emergence use is included on the registered label.
Early growth-stage treatment generally provides more effective control than treatment of mature, drought-stressed, or hardened weeds.
Uniform leaf coverage supports post-emergence performance without replacing the residual contribution from soil deposition.
Broadleaf-Weed Control
Susceptible broadleaf weeds include species within pigweed, lambsquarters, chickweed, smartweed, mustard, purslane, prickly lettuce, and related annual weed groups.
The exact weed spectrum is defined by the formulation concentration, crop, rate, timing, environmental conditions, and authorised label.
Grass-Weed Control
Linuron provides activity against susceptible annual grasses such as crabgrass, goosegrass, barnyardgrass, and selected foxtail species.
Established perennial grasses and deeply rooted perennial weeds generally require integrated control measures or a different herbicide program.
Horticultural and Minor Crops
Linuron has been particularly important in several horticultural and minor-crop systems where available herbicide options are limited.
Carrot, asparagus, parsnip, celery, potato, herb, and specialty-crop programs have used Linuron under crop-specific timing and residue restrictions.
Non-Crop Vegetation Management
Historical and specialised registrations have included shelterbelts, fence rows, roadsides, storage areas, and other non-crop locations.
Non-crop application requires an active authorisation covering the exact site and treatment method.
Research and Analytical Applications
Linuron functions as a reference photosystem II inhibitor in plant physiology, environmental fate, microbial degradation, toxicology, and endocrine research.
Certified Linuron standards support pesticide-residue testing in food, feed, soil, sediment, and water.
Isotopically labelled Linuron is used in metabolism, degradation, adsorption, and mass-balance investigations.
GRADE SELECTION AND PRODUCT SUITABILITY
Technical Material
Technical Linuron is selected for formulation manufacture and controlled industrial processing.
Active content, impurity profile, moisture, colour, melting behaviour, particle form, and analytical identity are the principal purchasing parameters.
Suspension Concentrate
A suspension concentrate is suitable for water-based liquid formulations containing finely dispersed Linuron.
Particle-size distribution, viscosity, sedimentation resistance, redispersibility, pourability, wet-sieve residue, foam, and freeze-thaw stability determine handling and spray performance.
Wettable Powder
A wettable powder provides a concentrated dry form for dilution in water.
Wettability, suspensibility, fineness, wet-sieve residue, dust generation, moisture, and active-content uniformity are central selection criteria.
Water-Dispersible Granule
A water-dispersible granule provides lower dust exposure and easier volumetric handling than a conventional wettable powder.
Granule strength, attrition resistance, disintegration time, dispersibility, suspensibility, wet-sieve residue, and storage stability determine product quality.
Flowable Concentrate
A flowable concentrate combines liquid dosing with a suspended solid active ingredient.
Rheology and particle stabilisation must permit complete container emptying and rapid redispersion after storage.
Analytical Grade
Analytical-grade Linuron is intended for instrument calibration, method validation, recovery studies, and residue quantification.
Certified identity, purity, uncertainty, traceability, packaging integrity, and storage information distinguish reference material from technical pesticide material.
FORMULATION AND PROCESS CONSIDERATIONS
Linuron’s limited water solubility makes particle engineering central to aqueous formulation performance.
Technical material is commonly micronised before incorporation into suspension concentrates, wettable powders, or water-dispersible granules.
Controlled particle size increases accessible surface area and supports uniform distribution in spray water.
Excessively fine particles can increase viscosity, dust generation, crystal-growth sensitivity, and formulation complexity.
Suspension-concentrate production requires efficient wetting before high-shear dispersion or milling.
Dispersants and rheology modifiers must prevent irreversible sedimentation while allowing the product to flow during pumping, filling, and application.
Temperature control during milling limits solvent loss, degradation, and unwanted changes in crystal form or particle distribution.
Wettable-powder production requires uniform blending with a compatible carrier, wetting agent, and dispersant.
Dust extraction and enclosed transfer systems reduce airborne exposure during milling, blending, and packaging.
Water-dispersible granules require rapid wetting and disintegration without excessive attrition during transport.
The granule binder must provide mechanical strength without impairing dispersion in the spray tank.
Spray mixtures containing suspended Linuron require continuous or intermittent agitation appropriate to the formulation.
Screens, strainers, and spray nozzles must accommodate the formulation’s particle-size specification.
Strong acids, strong bases, and strong oxidising agents are unsuitable formulation or storage companions.
Tank mixtures are governed by the authorised product label, crop tolerance, formulation compatibility, addition order, water quality, and agitation requirement.
Thorough equipment cleaning prevents carryover into sensitive crops.
QUALITY, SPECIFICATIONS AND DOCUMENTATION
A recognised technical-material profile uses a minimum Linuron content of 950 g/kg.
Relevant trace impurities identified as TCB, TCAB, and TCAOB are each controlled at a maximum concentration of 1 mg/kg.
These trace impurities require sensitive analytical methods with appropriate selectivity and low quantification limits.
A technical-material specification can include the following parameters.
Identity: Conforming chromatographic and spectroscopic identification
Linuron Content: Not less than 950 g/kg
TCB: Not more than 1 mg/kg
TCAB: Not more than 1 mg/kg
TCAOB: Not more than 1 mg/kg
Appearance: White crystalline solid or powder
Melting Range: 93–94°C
Moisture: Controlled for processing and storage stability
Particle Form: Suitable for the intended formulation process
High-performance liquid chromatography provides effective assay and related-substance determination.
Gas chromatography with sensitive selective detection or mass spectrometry supports trace chlorinated-impurity analysis.
The Certificate of Analysis records batch-specific identity, active content, relevant impurities, moisture, appearance, and other agreed purchasing parameters.
The Technical Data Sheet describes physical properties, intended commercial form, processing characteristics, packaging, and storage requirements.
The Safety Data Sheet provides hazard classification, exposure controls, first aid, firefighting measures, spill response, transport information, and disposal requirements.
Suspension-concentrate quality testing includes active content, pH, particle size, viscosity, pourability, suspensibility, wet-sieve residue, persistent foam, redispersibility, and accelerated-storage stability.
Wettable-powder quality testing includes active content, moisture, wettability, suspensibility, wet-sieve residue, persistent foam, dust characteristics, and accelerated-storage stability.
Water-dispersible-granule quality testing includes active content, moisture, granule strength, attrition resistance, disintegration, dispersibility, suspensibility, wet-sieve residue, dust, and storage stability.
Residue-sensitive procurement requires alignment between the formulation, authorised crop, treatment pattern, pre-harvest interval, destination market, and applicable maximum residue limit.
SAFETY AND REGULATORY CONSIDERATIONS
Linuron is harmful if swallowed and presents important chronic health and environmental hazards.
The harmonised European CLP classification assigns the signal word Danger.
Acute Toxicity, Oral, Category 4: H302, Harmful if swallowed
Carcinogenicity, Category 2: H351, Suspected of causing cancer
Reproductive Toxicity, Category 1B: H360Df, May damage the unborn child and is suspected of damaging fertility
Specific Target Organ Toxicity, Repeated Exposure, Category 2: H373, May cause damage to organs through prolonged or repeated exposure
Aquatic Acute Toxicity, Category 1: H400, Very toxic to aquatic life
Aquatic Chronic Toxicity, Category 1: H410, Very toxic to aquatic life with long-lasting effects
Repeated exposure can affect the blood-forming system, red blood cells, male reproductive system, and thyroid-related hormonal endpoints.
Relevant haematological effects include increased methemoglobin and sulfhemoglobin and changes associated with anaemia.
Linuron has antiandrogenic activity and can interfere with androgen-receptor signalling.
Exposure during pregnancy requires particularly strict prevention because of the reproductive Category 1B classification.
Dust, spray mist, contaminated clothing, ingestion, and prolonged skin contact are important occupational exposure routes.
Liquid formulations can introduce additional hazards from solvents, surfactants, preservatives, and other formulation ingredients.
Linuron is very toxic to aquatic plants and can also harm fish, aquatic invertebrates, birds, mammals, soil organisms, and non-target terrestrial plants.
Drift, runoff, drainage discharge, contaminated wash water, and improper disposal must be prevented.
The low vapour pressure limits atmospheric volatilisation, but airborne dust and spray aerosols can reach hazardous concentrations during handling or application.
Linuron is not approved as a plant-protection active substance in the European Union.
European authorisations were withdrawn following the 2017 non-renewal decision, and the final grace periods ended by 3 June 2018.
The agricultural use of Linuron in Türkiye has been completely prohibited since 1 August 2023.
Selected agricultural uses remain registered in certain other jurisdictions, including limited uses in the United States and Canada.
Linuron does not have registered residential use patterns in the United States.
Legal supply and use are determined by the destination country, product registration, crop or site, formulation, treatment method, residue limits, and end-use controls.
Analytical, research, manufacturing, and export transactions remain subject to the applicable pesticide and chemical-control requirements.
FIRST AID
General: Remove the affected person from further exposure and obtain medical or poison-centre assistance after significant contact, inhalation, or ingestion.
Inhalation: Move the affected person to fresh air and keep the person at rest in a position comfortable for breathing.
Provide oxygen or assisted respiration through trained personnel when breathing is impaired.
Skin Contact: Remove contaminated clothing and footwear immediately.
Wash the affected skin thoroughly with soap and running water for at least 15 to 20 minutes.
Eye Contact: Rinse cautiously with clean water for at least 15 to 20 minutes while holding the eyelids open.
Remove contact lenses after the first several minutes when this can be done easily and continue rinsing.
Ingestion: Rinse the mouth and obtain immediate medical advice.
Do not induce vomiting unless specifically instructed by medical personnel.
Do not give anything by mouth to an unconscious or convulsing person.
Note to Physicians: No specific antidote is established for Linuron exposure.
Treatment is symptomatic and supportive, with attention to respiratory function, circulation, complete blood count, haemolysis, and methemoglobin after significant exposure.
Cyanosis, unusual fatigue, headache, dizziness, shortness of breath, or poor response to supplemental oxygen can indicate methemoglobinemia.
HANDLING AND STORAGE
Handling
Use closed transfer, enclosed mixing, local exhaust ventilation, and dust-control equipment during industrial handling.
Avoid breathing dust, aerosol, vapour, and spray mist.
Prevent contact with skin, eyes, and clothing.
Wear chemical-resistant gloves, protective clothing, safety goggles, and suitable respiratory protection for the exposure conditions.
Use a face shield when splash or high-dust exposure is possible.
Do not eat, drink, smoke, or store food in Linuron handling areas.
Wash hands, face, and exposed skin thoroughly after work and before breaks.
Remove contaminated clothing promptly and wash it separately before reuse.
Restrict access to trained personnel and maintain controls appropriate to a reproductive Category 1B substance.
Ventilation
Provide effective local exhaust at charging, milling, blending, sampling, filling, and packaging points.
Use dust-tight connections and contained transfer systems for technical powder, wettable powder, and water-dispersible granules.
Provide suitable respiratory protection during maintenance, spill response, or operations that can exceed controlled workplace concentrations.
Storage
Store Linuron in a cool, dry, locked, and well-ventilated pesticide or hazardous-chemical area.
Keep containers tightly closed and protected from moisture, direct sunlight, excessive heat, and physical damage.
Segregate Linuron from food, feed, seed, medicines, drinking water, strong acids, strong bases, and strong oxidising agents.
Use secondary containment for liquid formulations and prevent access by children, animals, and unauthorised personnel.
Retain Linuron in the original labelled container or an approved compatible bulk system.
Do not transfer Linuron into food, beverage, or unmarked containers.
Incompatibilities
Avoid strong oxidising agents, strong acids, strong bases, and uncontrolled high-temperature processing.
Thermal decomposition and fire can produce hydrogen chloride, nitrogen oxides, carbon oxides, and other irritating or toxic fumes.
Spill Response
Isolate the spill area and keep unprotected personnel away.
Prevent dry powder from becoming airborne.
Collect solid material with a suitable filtered vacuum or carefully sweep it into sealed, labelled containers using dust-suppression methods.
Dike liquid formulations and absorb them with compatible inert material.
Prevent Linuron and contaminated wash water from entering drains, sewers, soil, surface water, or groundwater.
Collect contaminated absorbent, soil, equipment residues, and damaged packaging for authorised hazardous-waste disposal.
PACKAGING AND PROCUREMENT CONSIDERATIONS
Technical Linuron and dry formulations can be packed in sealed multilayer bags, lined fibre drums, lined composite containers, or other pesticide-compatible packaging.
Moisture-resistant inner liners protect active content, powder flow, dispersibility, and granule strength.
Suspension concentrates and flowable formulations require compatible high-density polyethylene containers, drums, or intermediate bulk containers with secure closures.
Packaging must withstand stacking, handling, temperature changes, vibration, and the transport conditions applicable to environmentally hazardous pesticides.
Technical solid Linuron is commonly transported as UN 3077, Environmentally Hazardous Substance, Solid, N.O.S. (Linuron), Class 9, Packing Group III, and Marine Pollutant.
Liquid formulations meeting environmental-hazard criteria can be transported as UN 3082, Environmentally Hazardous Substance, Liquid, N.O.S. (Linuron), Class 9, Packing Group III, and Marine Pollutant.
Procurement requests should identify the required product form, active concentration, impurity limits, particle-size characteristics, formulation code, packaging size, total quantity, destination country, intended application, and documentation requirements.
Technical-material purchasing should specify Linuron assay together with individual limits for TCB, TCAB, and TCAOB.
Suspension-concentrate purchasing should include particle size, viscosity, suspensibility, pourability, wet-sieve residue, persistent foam, and storage-stability requirements.
Wettable-powder purchasing should include wettability, suspensibility, moisture, fineness, wet-sieve residue, dust control, and active-content uniformity.
Water-dispersible-granule purchasing should include dispersibility, disintegration time, attrition resistance, suspensibility, dust, and storage stability.
Analytical-material purchasing should include certified purity, traceability, uncertainty, packaging atmosphere, storage temperature, and expiration information.
For Linuron grade information, impurity requirements, analytical documentation, packaging options, lawful application contexts, and supply planning, contact Ataman Kimya at +90 216 577 10 10 or info@atamankimya.com.
