Product Name: α-Methylstyrene
Chemical Formula: C9H10
Other Identifiers: Isopropenylbenzene, 2-Phenylpropene
CAS Number: 98-83-9
Recommended Use: Monomer for resins, polymers, chemical intermediate, solvent applications
Supplier Details: Manufacturer's name, contact phone, address from the source
Emergency Phone: Refer to manufacturer listing or CHEMTREC number
Hazard Classification: Flammable liquid (Category 3), Acute Toxicity Oral (Category 4), Skin Irritation (Category 2), Eye Irritation (Category 2A), Specific target organ toxicity — single exposure (Category 3, Narcotic Effects)
Label Elements: Signal word: Warning; Hazard statements include "Flammable liquid and vapor," "Harmful if inhaled or swallowed," "Causes skin and eye irritation," "May cause drowsiness or dizziness"
Precautionary: Keep away from heat, sparks, open flames, and hot surfaces. Use explosion-proof equipment and ensure good ventilation
Symbols: Exclamation Mark, Flame pictogram
Routes of Exposure: Inhalation, ingestion, dermal, ocular
Health Effects: Causes irritation to eyes, skin, and respiratory tract; May cause headaches, dizziness, or central nervous system depression on high exposure levels
Chemical Name: α-Methylstyrene
Synonyms: Isopropenylbenzene; 2-Phenylpropene
Concentration: ≥99% purity
Impurities: Trace levels of phenylacetone, cumene, and other hydrocarbons considered in toxicology assessment
CAS Number: 98-83-9
Substance/Mixture: Substance
Inhalation: Move exposed person to fresh air. If symptoms persist, seek medical attention. Provide artificial respiration or oxygen if breathing is difficult
Skin Contact: Remove contaminated clothing and footwear immediately. Wash skin thoroughly with soap and water. Do not reuse clothing before laundering
Eye Contact: Rinse eyes carefully with water for several minutes, lifting upper and lower lids. Remove contact lenses if present and continue rinsing. Get medical attention if irritation persists
Ingestion: Rinse mouth, do not induce vomiting unless directed by medical personnel. Never give anything by mouth if unconscious. Seek medical attention promptly
Most Important Symptoms/Effects: Irritation to eyes/skin, headache, dizziness, possible unconsciousness with high vapor concentrations
Suitable Extinguishing Media: Dry chemical, alcohol-resistant foam, carbon dioxide, water spray
Unsuitable Media: Do not use straight water stream that can spread fire
Specific Hazards: Vapors are heavier than air and may travel to ignition source, causing flashback; formation of toxic fumes such as carbon monoxide, carbon dioxide on combustion
Protective Equipment: Full protective clothing and self-contained breathing apparatus
Special Precautions: Cool containers with water spray to prevent explosion due to heat exposure. Remove personnel from area if risk of explosion. Handle runoff carefully to avoid environmental contamination
Personal Precautions: Remove sources of ignition, ventilate affected area, use personal protective equipment such as chemically resistant gloves, goggles, and anti-static clothing
Environmental Precautions: Prevent entry into drains, waterways, ground or soil; contain spill with inert, non-combustible material
Methods for Cleanup: Absorb with vermiculite, dry sand, or earth; place material in suitable, labeled containers for proper disposal. Clean contaminated surfaces thoroughly. Use spark-proof tools and explosion-proof equipment for handling.
Precautions: Store in tightly closed containers, in a cool, dry, well-ventilated location away from heat and direct sunlight
Handling: Use only non-sparking tools and explosion-proof equipment. Avoid inhalation of vapor and skin contact. Practice good hygiene by washing hands after handling
Safe Incompatibilities: Separate from strong oxidizing agents, acids, and bases that could initiate polymerization
Storage Temperature: Preferably below 30°C, away from ignition sources. Store in original or compatible chemical containers
Other Practices: Keep container grounded and bonded; handle under nitrogen blanket if polymerization risk is high
Exposure Limits: OSHA TWA: 50 ppm (215 mg/m³), ACGIH TLV: 50 ppm
Engineering Controls: Use local exhaust ventilation and process enclosure if possible
Personal Protective Equipment: NIOSH-approved respirator for organic vapor exposure; chemical-splash goggles; acid-resistant gloves (nitrile, neoprene or PVC); flame-retardant, antistatic laboratory coat
Hygiene Measures: Wash hands before eating, drinking, or smoking; remove contaminated clothing promptly
Environmental Controls: Avoid release to environment by using closed system transfer and proper waste containers
Appearance: Clear, colorless to pale yellow liquid
Odor: Sweet, aromatic resembling styrene
Melting Point: -23°C (-9°F)
Boiling Point: 165–166°C (329–331°F)
Flash Point: 42°C (108°F, closed cup)
Evaporation Rate: Moderate (similar to ethylbenzene)
Vapor Pressure: 2.1 mmHg at 25°C
Vapor Density: ~4.6 (Air = 1)
Relative Density: 0.91–0.92 g/cm³
Solubility: Insoluble in water; miscible with most organic solvents
Partition Coefficient (log Kow): 3.7
Viscosity: Low; flows easily
Autoignition Temperature: 491°C
Upper/Lower Explosion Limits: 1.0–6.2% (vol%)
Decomposition Products: Carbon monoxide, carbon dioxide, other aromatic hydrocarbons
Chemical Stability: Stable under recommended storage conditions, but can polymerize violently if exposed to heat, light, peroxides, or acids
Conditions to Avoid: High temperatures, open flames, strong sunlight, absence of free radical inhibitors
Incompatible Materials: Strong oxidizers (e.g., nitric acid, peroxides), acids, bases, iron, aluminum; sources of ignition
Hazardous Decomposition: Combustion produces carbon monoxide, carbon dioxide, phenolic compounds
Polymerization: May occur with liberation of heat; inhibitors (BHT or similar) added during manufacture to reduce risk
Acute Toxicity: Oral LD50 (rat): ~1750 mg/kg; Dermal LD50 (rabbit): >5000 mg/kg; Inhalation LC50: Not fully established
Routes of Exposure: Ingestion, inhalation, skin, eyes
Symptoms: Irritation, headache, nausea, CNS effects (drowsiness, dizziness), respiratory tract irritation, sensitization not reported in animal studies
Chronic Effects: Prolonged exposure may affect liver and kidneys; animal studies suggest no significant reproductive or carcinogenic effects
Carcinogenicity: Not listed by IARC, NTP, OSHA as a confirmed human carcinogen
Irritation/Corrosivity: Causes moderate to severe temporary irritation to eyes, skin, and respiratory tract
Delayed and Immediate Effects: Central nervous system depression at high concentrations
Ecotoxicity: Toxic to aquatic organisms; LC50 (96 hr, fish): 4.2 mg/L; EC50 (48 hr, daphnia): 10 mg/L
Persistence and Degradability: Readily biodegradable, but can form tarry residues; tendency to adsorb to soil and organic matter
Bioaccumulative Potential: High with log Kow (3.7); potential for accumulation in aquatic food chains
Mobility in Soil: Low water solubility leads to moderate mobility; risk of leaching low but may volatilize from soil, causing air release
Other Adverse Effects: Volatile organic compound, contributes to ground-level ozone formation in urban air
Disposal of Chemical: Dispose of as hazardous waste according to Federal, State, and Local regulations. Incineration under controlled conditions preferred
Contaminated Packaging: Triple rinse and offer for recycling after puncturing; dispose of in accordance with environmental legislation
Precautions: Do not mix with other chemicals; avoid release to sewers, waterways, or soil
EPA Waste Number: U266 (listed hazardous waste)
UN Number: UN 2303
Proper Shipping Name: α-Methylstyrene
Transport Hazard Class: 3 (Flammable liquids)
Packing Group: III
Labels Required: Flammable liquid
Special Provisions: Must travel in approved containers with proper placarding; keep separated from oxidizers
Marine Pollutant: Not regulated as maritime pollutant, but spill control required due to aquatic toxicity
OSHA: Classified as hazardous; requirements for reporting, training, and controls by OSHA Hazard Communication Standard (29 CFR 1910.1200)
TSCA: Listed on TSCA Inventory
SARA: SARA 302/304 EHS: Not listed; SARA 311/312: Immediate (acute), Delayed (chronic), Fire hazard; SARA 313: Not subject to reporting
California Prop 65: Not listed as a carcinogen or reproductive toxicant
REACH/CLP (EU): Registered; GHS-classified; PIC Regulation applies
State Regulations: Subject to right-to-know reporting in states such as New Jersey, Pennsylvania, Massachusetts
Other International Regulations: Complies with WHMIS (Canada), AICS (Australia), DSL (Canada)
