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Chemical Name: Mesityl oxide
Chemical Formula: C6H10O
Common Names: 4-Methyl-3-penten-2-one, Isobutenyl methyl ketone
Appearance: Colorless to slightly yellow liquid
Odor: Sweet, acetone-like
Uses: Industrial solvent, intermediate in organic synthesis
CAS Number: 141-79-7
Acute Risks: Vapors irritate eyes, nose, throat; inhalation causes dizziness, headaches, nausea; high concentrations may depress nervous system
Fire Risk: Flammable; vapors form explosive mixtures with air; ignition possible from static discharge
Environmental Hazard: Harmful to aquatic life in concentrated spills
Chronic Risks: Prolonged exposure can damage liver and kidneys; repeated skin contact dries and cracks skin
Regulatory Classification: GHS label for flammable liquid and acute toxicity
Main Ingredient: Mesityl oxide (C6H10O) - typically above 95% purity
Contaminants: Minor ketones, water traces, side reaction byproducts may appear in technical-grade samples
Inhalation: Remove to fresh air immediately, loosen clothing, offer oxygen if person has trouble breathing; seek medical help if symptoms persist
Skin Contact: Remove contaminated clothing; rinse skin with soapy water for several minutes; watch for delayed irritation
Eye Contact: Rinse eyes with water for at least 15 minutes, hold eyelids open, check for redness or persistent pain
Ingestion: Do not induce vomiting; rinse mouth and provide water if the person is conscious; get medical attention quickly
Suitable Extinguishing Media: Use foam, dry chemical, carbon dioxide; avoid high-pressure water streams which may spread the liquid
Fire Hazards: Vapors heavier than air collect in low places and travel great distances; invisible vapor can ignite at ignition sources far from spill
Firefighter Protection: Wear self-contained breathing apparatus, protective gear; stay upwind and cool containers with water spray
Special Precautions: Prevent spillage from entering drains to avoid explosive vapor hazards
Personal Protection: Evacuate area of unprotected staff; ventilate area; avoid sparks and open flames
Containment: Use absorbents like sand or vermiculite to contain small spills; dikes for larger releases
Cleanup: Shovel absorbed material into containers for disposal; wash spill site with copious water after initial cleanup
Environmental Precautions: Block liquid from entering sewers, watercourses, or confined spaces; notify authorities for large spills
Handling: Use non-sparking tools and explosion-proof equipment; ground containers during transfer; keep containers tightly sealed
Avoided Activities: Do not breathe vapor; prevent skin and eye contact; keep away from heat and oxidizers
Storage: Store in cool, dry, well-ventilated areas away from sunlight or incompatible substances; store only in containers made for flammable liquids
Special Attention: Check container seals regularly; inspect for corrosion
Exposure Limits: OSHA PEL 100 ppm (410 mg/m³) as an 8-hour time-weighted average; NIOSH REL 100 ppm
Engineering Controls: Use local exhaust ventilation where vapor concentrations may increase; maintain proper air flow
Personal Protection: Wear chemical-resistant gloves (nitrile, neoprene); use splash goggles or face shield; don flame-resistant coveralls if risk of splashing
Respiratory Protection: Use respirators approved for organic vapors in poorly ventilated or high exposure settings
Hygiene Measures: Wash hands after handling; no eating, drinking, or smoking in work area
Boiling Point: 129°C
Melting Point: -59°C
Flash Point: 27°C (closed cup)
Vapor Pressure: 12 mm Hg at 20°C
Solubility: Slightly soluble in water; miscible with most organic solvents
Density: 0.859 g/cm³ at 20°C
Evaporation Rate: Moderate (relative to butyl acetate)
Vapor Density: 3.4 (air = 1)
Appearance: Clear liquid
Chemical Stability: Stable under recommended storage conditions
Reactive Incompatibility: Avoid strong oxidizing agents, strong acids, alkali metals
Hazardous Decomposition: Combustion yields carbon monoxide, carbon dioxide, irritating fumes
Acute Effects: Eye, skin, and respiratory irritation; central nervous system depression in high doses
Ingestion: Can harm gastrointestinal, renal, and hepatic systems
Skin Sensitization: Possible dermatitis on repeated skin contact
Chronic Exposure: Animal studies link prolonged high exposures to liver and kidney changes, but workplace exposures rarely reach those levels
Carcinogenicity: Not listed by IARC or NTP as a confirmed carcinogen
Aquatic Toxicity: Harmful to fish and aquatic invertebrates in concentrated releases
Persistence & Degradability: Readily degrades by atmospheric oxidation; moderate rate in water, faster in air
Bioaccumulation: Low expected potential; breaks down in biological treatment systems
Terrestrial and Water Hazards: Spilled liquid evaporates quickly, reducing long-term environmental risk except in confined water bodies
Waste Treatment: Take up liquid in absorbent non-combustible material and send to incineration site
Local Regulations: Follow national and regional instructions; never dump into public drains or sewers
Reuse & Recycling: Only attempt by professionals with specialized equipment; containers must be fully emptied and triple-rinsed before reuse or recycling
UN Number: 1229
Shipping Name: Mesityl oxide
Transport Hazard Class: 3 (Flammable liquid)
Packing Group: III
Special Precautions: Keep away from heat, open flames; transport in dedicated flammable liquid vehicles if possible
Label Requirements: Flammable liquid symbol must be visible on packages
Chemical Inventory: Listed by key international regulatory bodies involved in chemical trade
Worker Protection: Covered under OSHA, EU REACH, and similar occupational exposure laws
Labeling: Requires hazard and precautionary statements on commercial packaging
Emergency Planning: Included in national lists requiring risk management, fire protection, and emergency planning in industrial facilities
