Methylcyclopentadien

0.941 (USCG, 1999) - Less dense than water; will float

0.941 @25 °C

392 °F at 760 mmHg (USCG, 1999)

200 °C @760 [mm Hg]

14.2 [mmHg]

7.5 [mm Hg] @47.8 °C

Methylcyclopentadiene dimer, [liquid] appears as a colorless liquid. Slightly less dense than water and insoluble in water. Hence floats on water.

Liquid

Colorless liquid; [CAMEO] Pale yellow liquid with a hydrocarbon odor; [ExxonMobil MSDS]

Chemical: 4,7-Methano-1H-indene, 3a,4,7,7a-tetrahydrodimethyl-

4,7-Methano-1H-indene, 3a,4,7,7a-tetrahydrodimethyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 4,7-Methano-1H-indene, 3a,4,7,7a-tetrahydrodimethyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Methylcyclopentadiene dimer: Does not have an individual approval but may be used under an appropriate group standard

Harmful if swallowed, inhaled or absorbed through skin. Vapor or mist is irritating to the eyes, mucous membrane, upper respiratory tract. Exposure can cause nausea, headache, and vomiting. May contain 0.5% Benzene, a known carcinogen. (USCG, 1999)

May auto-oxidize on exposure to air forming explosive peroxides; [CAMEO] Liquid causes smarting of skin and first degree burns on short exposure; May cause second degree skin burns from longer exposure; Vapor or mist causes eye, mucous membrane, and upper respiratory tract irritation; Inhalation may cause dizziness, difficulty breathing, and loss of consciousness; [CHRIS] Effects to the kidney (increased hyaline droplets in all treated males) and liver (hepatocellular hypertrophy with increased liver weights in females at 100 mg/kg/day and males at 300 mg/kg/day) observed in 28-day oral study of rats; Gross and histopathological changes of the liver and kidney observed in 9-day inhalation study of rats; No reproductive toxicity observed in rats; Developmental toxicity (lower pup birth weight and weight gain) seen in the presence of maternal toxicity in rats; Evidence of neurotoxicity in rats; [EPA ChAMP: Hazard Characterization] Contains 0-0.5% benzene (CAS# 71-43-2) and 0-3.5% dicyclopentadiene (CAS# 77-73-6); A skin and eye irritant; An aspiration hazard by ingestion (may cause lung injury); Harmful by inhalation; [ExxonMobil MSDS] See Dicyclopentadiene.

METHYLCYCLOPENTADIENE DIMER may react vigorously with strong oxidizing agents. Can react exothermically with reducing agents to release gaseous hydrogen. May undergo autoxidation upon exposure to the air to form explosive peroxides. Explosions in ammonia synthesis gas have been traced to the breakdown of addition products of dienes similar to this diene and oxides of nitrogen produced from the interaction of nitrogen oxide and oxygen [Bretherick, 1995].

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:；CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient. CAUTION: For mixtures containing alcohol or polar solvent, alcohol-resistant foam may be more effective.；SMALL FIRE: Dry chemical, CO2, water spray or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam.；LARGE FIRE: Water spray, fog or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam. Avoid aiming straight or solid streams directly onto the product. If it can be done safely, move undamaged containers away from the area around the fire.；FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. For petroleum crude oil, do not spray water directly into a breached tank car. This can lead to a dangerous boil over. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

INHALATION: Call a physician. Remove the victim to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen.；EYES OR SKIN: Immediately flush with copious amounts of water for 15 minutes while removing contaminated clothing and shoes. Assure adequate flushing of the eyes by holding eyelids open with fingers. (USCG, 1999)

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:；ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor-suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean, non-sparking tools to collect absorbed material.；LARGE SPILL: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor, but may not prevent ignition in closed spaces. (ERG, 2024)

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:；IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions.；LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet).；FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

13 [mg/m3]

140 [mg/m3]

830 [mg/m3]

Neurotoxin - Acute solvent syndrome；Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.；Nephrotoxin - The chemical is potentially toxic to the kidneys in the occupational setting.；Dermatotoxin - Skin burns.

Chemical: 4,7-Methano-1H-indene, 3a,4,7,7a-tetrahydrodimethyl-

4,7-Methano-1H-indene, 3a,4,7,7a-tetrahydrodimethyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 4,7-Methano-1H-indene, 3a,4,7,7a-tetrahydrodimethyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Methylcyclopentadiene dimer: Does not have an individual approval but may be used under an appropriate group standard