2,3-Dimethylbutane

H225: Highly Flammable liquid and vapor [Danger Flammable liquids]

H304: May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H336: May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P319, P321, P331, P332+P317, P362+P364, P370+P378, P391, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H225 (100%): Highly Flammable liquid and vapor [Danger Flammable liquids]

H304 (100%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]

H336 (99.7%): May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H411 (100%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

Aggregated GHS information provided per 326 reports by companies from 22 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. Volatile chemicals have a high risk of being aspirated into the victim's lungs during vomiting which increases the medical problems. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. IMMEDIATELY transport the victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

Specific First Aid:

· Wash skin with soap and water.

· In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

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)

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· 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.

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)

Immediate precautionary measure

· Isolate spill or leak area for at least 50 meters (150 feet) in all directions.

· Consider initial downwind evacuation for at least 300 meters (1000 feet).

· 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.

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

VENTILATION CONTROL: THE BASIC VENTILATION METHODS ARE LOCAL EXHAUST VENTILATION AND DILUTION OR GENERAL VENTILATION.

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)

...MATERIALS WHICH ARE TOXIC AS STORED OR...DECOMP INTO TOXIC COMPONENTS...SHOULD BE STORED IN COOL, WELL-VENTILATED PLACE, OUT OF DIRECT RAYS OF SUN, AWAY FROM AREAS OF HIGH FIRE HAZARD...PERIODICALLY INSPECTED & MONITORED. INCOMPATIBLE MATERIALS SHOULD BE ISOLATED...

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

500.0 [ppm]

100 ppm (350 mg/m³)

510 ppm (1800 mg/m³) [15 minutes]

200.0 [ppm]

500 ppm [1979]

1000 ppm [1979]

Chronic Inhalation: 0.6 ppm (L134)

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.

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

Wear rubber gloves, face shield, work gown, all purpose canister mask.

2,3-dimethylbutane appears as a clear colorless liquid with a petroleum-like odor. Flash point -20 °F. Less dense than water and insoluble in water. Vapors heavier than air.

Colorless liquid with an odor of petroleum; [CAMEO]

Clear liquids with mild, gasoline-like odors.

COLORLESS LIQUID

136.4 °F at 760 mmHg (NTP, 1992)

57.9 °C @ 760 MM HG

136.4 °F

-199.3 °F (NTP, 1992)

-128.8 °C

Heat of Fusion at Melting Point = 7.9914X10+5 J/kmol

-199.3 °F

-20 °F (NTP, 1992)

-20 °F (-29 °C) (CLOSED CUP)

less than 1 mg/mL at 74.3 °F (NTP, 1992)

SOL IN ETHANOL, ETHER; VERY SOL IN ACETONE

Water solubility = 22.5 mg/l at 25 °C

0.6616 at 68 °F (NTP, 1992) - Less dense than water; will float

0.6616 @ 20 °C/4 °C

3 (NTP, 1992) - Heavier than air; will sink (Relative to Air)

3.0 (AIR= 1)

200 mmHg at 70 °F ; 400 mmHg at 102 °F (NTP, 1992)

235.0 [mmHg]

Vapor pressure = 235 mm Hg at 25 °C

200 mmHg at 70 °F

Log Kow = 3.42

788 °F (NTP, 1992)

761 °F (405 °C)

Liquid viscosity = 4.5661X10-4 @ 273.15 deg K

3877.86 kJ/mol

29.2 kJ/mol @ 25 °C

2.3229X10-2 N/m @ melting point

SADTLER REF NUMBER: 687 (IR, PRISM); INDEX OF REFRACTION: 1.3750 @ 20 °C/D

Liquid molar volume = 0.131050 cu m/kmol

IG Heat of Formation = -1.7680X10+8 J/kmol

VAPOR PRESSURE 400 MM HG @ 39.0 °C

Schoenflies notation

Boiling point

Chemical bond

Chemical diffusion

Composition

Highly flammable. Insoluble in water.

Hydrocarbons, Aliphatic Saturated

Highly Flammable

Saturated aliphatic hydrocarbons, such as 2,3-DIMETHYLBUTANE, may be incompatible with strong oxidizing agents like nitric acid. Charring of the hydrocarbon may occur followed by ignition of unreacted hydrocarbon and other nearby combustibles. In other settings, aliphatic saturated hydrocarbons are mostly unreactive. They are not affected by aqueous solutions of acids, alkalis, most oxidizing agents, and most reducing agents. This compound is incompatible with oxidizing materials. It is also incompatible with oxygen. (NTP, 1992).

Hexane's toxicity is caused by it neurotoxic metabolite, 2,5-hexanedione. It damages the central and peripheral nervous system by causing axonal swelling and degeneration. 2,5-Hexanedione also reacts with lysine side-chain amino groups in axonal cytoskeletal proteins to form pyrroles. This results in neurofilament cross-linking and loss of function. (L175)

No indication of carcinogenicity to humans (not listed by IARC).

Hexane mainly affects the nervous system. It causes degeneration of the peripheral nervous system (and eventually the central nervous system), starting with damage to the nerve axons. Exposure to hexane may also damage the lungs and reproductive system. (L977, L978)

Oral (L175) ;inhalation (L175) ;dermal (L175)

Breathing large amounts of hexane causes numbness in the feet and hands, followed by muscle weakness in the feet and lower legs. Continued exposure may lead to paralysis of the arms and legs. However, if removed from the exposure, recovery occurs in 6 months to a year. Inhalation of high concentrations produces first a state of mild euphoria, followed by somnolence with headaches and nausea. (L175, A121)

Neurotoxin - Acute solvent syndrome

ACGIH Carcinogen - Confirmed Animal.

Subchronic toxicity was evaluated in two groups of 10 male Fischer 344 rats receiving 0.5 or 2.0 g/kg 2,3-dimethylbutane once daily by oral gavage, 5 days/week for four weeks. Mortality was observed in the low dose group (2 rats), and in the high dose group (3 rats) during the test; surviving animals were sacrificed 24 hours after administration of the final dose. Terminal body weights were statistically significantly (students t-test, p < 0.05) lower in high dose, but not in low dose groups. Mean kidney weights were significantly (p < 0.05) higher in both high and low dose groups. Gross necropsy observations in individual animals included lightly speckled cortical surfaces in kidneys, clear fluid in abdomens, reddened thymal lobes, congested lungs, scattered pale and dark foci on lungs, grey discoloration on livers, prominent lobular patterns on livers, diffuse reddening of cecums, reddened mediastinal lymph nodes, dark foci on nonglandular stomachs, moderately enlarged adrenals, hemorrhages in hearts, and mottled lungs, thymus glands and left kidneys. Histopathological findings in kidneys included hyaline droplet change (in 10 low, and 10 high dose rats), regenerative epithelium (in 10 low, and 10 high dose rats), and tubular dilatation with granular material (in 6 low, and 4 high dose rats). These kidney findings were used to calculate an index of hydrocarbon nephrotoxicity, defined as a sum of scores ranging from 1 to 4 in severity for each endpoint for the degree of hyaline droplet change, number of foci of regenerative epithelium, and the number of foci of tubular dilatation with granular material; values were 7.6 for the low dose group, 6.1 for the high dose group, and 3.0 for the saline treated control group. Additional histopathological findings in kidneys included mononuclear cell infiltrate (in 7 low, and 9 high dose rats), hyaline casts (in 5 low, and 2 high dose rats), and tubular mineralization (in 2 low dose rats).

2,3-Dimethylbutane's production and use as a high octane fuel and in organic synthesis may result in its release to the environment through various waste streams. 2,3-Dimethylbutane is released into the atmosphere from auto, biomass combustion, and gasoline vapor emissions. If released to soil, 2,3-dimethylbutane will have low mobility. Volatilization of 2,3-dimethylbutane may be important from moist and dry soil surfaces. Insufficient date are available to determine the rate or importance of biodegradation of 2,3-dimethylbutane in soil or water. If released to water, 2,3-dimethylbutane would adsorb to suspended solids and sediment. 2,3-Dimethylbutane would volatilize from water surfaces with estimated half-lives for a model river and model lake of 2.7 hours and 3.7 days, respectively. An estimated BCF value of 230 suggests that 2,3-dimethylbutane will bioconcentrate in aquatic organisms. If released to the atmosphere, 2,3-dimethylbutane will exist as a vapor. Vapor-phase 2,3-dimethylbutane is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals with an estimated half-life of about 5.4 days. Vapor-phase 2,3-dimethylbutane is also degraded in the atmosphere by reaction with nitrate radicals with an estimated half-life of about 334 days. Exposure to 2,3-dimethylbutane will occur primarily through inhalation. (SRC)

2,3-Dimethylbutane's production and use as a high octane fuel and in organic synthesis(1) may result in its release to the environment through various waste streams(SRC). 2,3-Dimethylbutane is released into the atmosphere from auto, biomass combustion, and gasoline vapor emissions(2).

TERRESTRIAL FATE: Based on a recommended classification scheme(1), an estimated Koc value of 1700(SRC), determined from an experimental log Kow(2) and a recommended regression-derived equation(3), indicates that 2,3-dimethylbutane will have low mobility in soil(SRC). Volatilization of 2,3-dimethylbutane may be important from moist soil surfaces(SRC) given an estimated Henry's Law constant of 1.2 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure(4) and water solubility(5), and from dry soil surfaces(SRC) based on an experimental vapor pressure of 235 mm Hg(4). Insufficient data are available to determine the rate or importance of biodegradation of 2,3-dimethylbutane(SRC).

AQUATIC FATE: Based on a recommended classification scheme(1), an estimated Koc value of 1700(SRC), determined from an experimental log Kow(2) and a recommended regression-derived equation(3), indicates that 2,3-dimethylbutane would adsorb to suspended solids and sediment(SRC) in the water. 2,3-Dimethylbutane would volatilize from water surfaces based on an estimated Henry's Law constant of 1.2 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure(4) and water solubility(5). Estimated half-lives for a model river and model lake are 2.7 hours and 3.7 days, respectively(3,SRC). An estimated BCF value of 230(3,SRC), from an experimental log Kow(2), suggests that 2,3-dimethylbutane will bioconcentrate in aquatic organisms(SRC) according to a recommended classification scheme(6). Insufficient data are available to determine the rate or importance of biodegradation of 2,3-dimethylbutane(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,3-dimethylbutane, which has an experimental vapor pressure of 235 mm Hg at 25 °C(2) will exist as a vapor in the ambient atmosphere. Vapor-phase 2,3-dimethylbutane is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 5.4 days(3,SRC). Vapor-phase 2,3-dimethylbutane is also degraded in the atmosphere by reaction with nitrate radicals(4); the half-life for this reaction in air is estimated to be about 334 days(4,SRC).

Using the Clark oxygen electrode, a resting cell suspension of Corynebacterium (which used n-octane as sole carbon and energy source) oxidized 2,3-dimethylbutane with an activity of 43% that of n-octane (specific activity 78.5 ul oxygen/hour/mg cells)(1). 2,3-Dimethylbutane was not able to support the growth of any of the 32 microorganisms isolated from groundwater(2). Pure culture studies provide little insight into the biodegradation of 2,3-dimethylbutane in environmental samples(3,SRC).

The rate constant for the vapor-phase reaction of 2,3-dimethylbutane with photochemically produced hydroxyl radicals has been experimentally determined to be 6.2X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 5.4 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC). The rate constant for the vapor-phase reaction of 2,3-dimethylbutane with nitrate radicals has been experimentally determined to be 1.2X10-16 cu cm/molecule-sec at 25 °C(2). This corresponds to an atmospheric half-life of about 334 days at an atmospheric concentration of 2X10+8 NO3 radicals per cu cm(2,SRC).

An estimated BCF value of 230 was calculated for 2,3-dimethylbutane(SRC), using an experimental log Kow of 3.42(1) and a recommended regression-derived equation(2). According to a recommended classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms will be an important fate process(SRC).

The Koc of 2,3-dimethylbutane is estimated as approximately 1700(SRC), using an experimental log Kow of 3.42(1) and a regression-derived equation(2,SRC). According to a recommended classification scheme(3), this estimated Koc value suggests that 2,3-dimethylbutane has low mobility in soil(SRC).

The Henry's Law constant for 2,3-dimethylbutane is estimated as 1.2 atm-cu m/mole(SRC) from its experimental values for vapor pressure, 235 mm Hg(1), and water solubility, 22.5 mg/l(2). This value indicates that 2,3-dimethylbutane will volatilize rapidly from water surfaces(3,SRC). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec) is estimated as approximately 2.7 hours(3,SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec) is estimated as approximately 3.7 days(3,SRC). 2,3-Dimethylbutane's high vapor pressure(1) and high Henry's Law constant(1,2,SRC) indicate that volatilization from dry and moist soil surfaces may occur(SRC).

A study conducted in Atlanta found the average source profiles of 2,3-dimethylbutane in roadway, whole gas (average of six octanes), whole gas (87 octane), whole gas (89 octane), whole gas (92/93 octane), headspace gas (at 24 °C and average of six octanes), headspace gas (at 32 °C and average of six octanes), airport, and aircraft emissions were: 0.863, 0.88, 0.96, 0.83, 0.70, 1.49, 1.55, 0.55, and 0.332 ppbC%, respectively(1). A study conducted in Chicago found the average concentration of 2,3-dimethylbutane/2-methylpentane in regular fuel (87 octane), mid-grade (89 octane), premium (93 octane), hot soak, cold start, roadway, and petroleum refinery emissions to be 3.2, 2.34, 1.33, 4.62, 4.4, 3.21, and 2.62 wt%, respectively(2). Refueling emission profiles for 2,3-dimethylbutane/2-methylpentane were 2.58 and 2.26 wt% in the summer and winter, respectively and 4.17 and 3.2 wt% in Atlanta and Chicago respectively(2). The emission rate of 2,3-dimethylbutane is estimated to be 5 metric tons/day in a southern California mountain forest location impacted with urban photochemical smog(3). The profile for 2,3-dimethylbutane in gasoline engine exhaust (noncatalyst and catalyst equipped), unburned gasoline (whole and headspace vapors) was 0.6, 1.0, 1.1, and 1.1 wt%, respectively(4). 2,3-Dimethylbutane was identified in influent and effluent food refuse gas samples(5). The average 2,3-dimethylbutane contribution to emissions from 67 different vehicles was 0.6 wt% in Sydney, Australia(6). 2,3-Dimethylbutane content in moped exhaust with alkylate-based and reformate-based fuels was 1.2 and 1.5 wt% (alkylate: exhaust and fuel) and 0.48 and 0.6 (reformate: exhaust and fuel)(7).

In Southern California, the 2,3-dimethylbutane profile for various emissions for vehicle exhaust was 0.81, 0.89, 1.24, 0.00, 1.68, and 1.91 wt% for a 46 car study, 13 samples from the Caldecott Tunnel, cold start, stabilized, hot start, and from an older fleet, respectively(1). Gasoline emission profiles for 2,3-dimethylbutane are as follows: 4.99, 5.36, 3.34, 2.59, 2.32, 2.33, and 2.03 wt% for diurnal evaporative emissions (older fleet), hot soak evaporative emissions (older fleet), running loss (older fleet), summer liquid gas, winter liquid gas, summer gas headspace, and winter gas headspace, respectively(1). In oil field emissions (Tulsa, OK), 2,3-dimethylbutane was detected at average concentration of 24.5 ppbC and approximately 12 ppbC for two different samples(2). The concentration of 2,3-dimethylbutane in gasoline vapors from refueling cars at service stations ranged between 0.005 and 9.2 ppm(3).

URBAN/SUBURBAN: 2,3-Dimethylbutane was identified in downtown Los Angeles morning air at concns of 2-8 ppbv(1). A study of Washington, DC air identified 2,3-dimethylbutane in 62.5% of the samples at an average concn of 0.21 ppbv(2). 2,3-Dimethylbutane was identified in the air of the following industrial cities of the USSR: Leningrad, Tashkent, Baku, Tbilisi, Kemerovo, and Murmansk(3). 2,3-Dimethylbutane was also identified in the air of three large South African cities: Pretoria, Johannesburg, and Durban(4). 2,3-Dimethylbutane was identified in the air of Sydney, Australia at an average concn of 0.9 ppbv(5). 2,3-Dimethylbutane was identified in the air of Huntington Park, Los Angeles at 0.6 ppb (ground level, afternoon), 7.8 (groundlevel, morning), 2.1 (at 1500 ft, morning), and 0.1 ppb (at 2200 ft, morning)(6). A study conducted in the Riverside, CA area identified 2,3-dimethylbutane at concns of approximately 0.5, 0.2, 0.5, 0.7, and 0.6 ppb at five different sites(7). 2,3-Dimethylbutane was identified in the air of suburban, urban, and source dominated sites at the following average concns: 0.572 (219 samples), 0.6 (521 samples), and 0.666 ppbv (20 samples), respectively(8).

RURAL/REMOTE: 2,3-Dimethylbutane was identified in the air of six remote sites in North Carolina at the following median concns (ppb carbon): Roan Mountain, 0.1; Grandfather Mountain, 0.2; Linville Gorge, 0.1; Rich Mountain, 0.1; Boone Center, 3.1; and Boone Outskirts, 0.3(1).

The average concentration of 2,3-dimethylbutane in the air from gasoline vapors, to which petroleum industry workers may be exposed, for outside operators is 0.232 mg/cu m, for transport drivers is 0.958 mg/cu m, and for service attendants is 1.319 mg/cu m(1).

Occupational exposure to aliphatic hydrocarbons, such as 2,3-dimethylbutane(SRC), will occur primarily through inhalation(1).

2,3-Dimethylbutane's production and use as a high octane fuel and in organic synthesis may result in its release to the environment through various waste streams. 2,3-Dimethylbutane is released into the atmosphere from auto, biomass combustion, and gasoline vapor emissions. If released to soil, 2,3-dimethylbutane will have low mobility. Volatilization of 2,3-dimethylbutane may be important from moist and dry soil surfaces. Insufficient date are available to determine the rate or importance of biodegradation of 2,3-dimethylbutane in soil or water. If released to water, 2,3-dimethylbutane would adsorb to suspended solids and sediment. 2,3-Dimethylbutane would volatilize from water surfaces with estimated half-lives for a model river and model lake of 2.7 hours and 3.7 days, respectively. An estimated BCF value of 230 suggests that 2,3-dimethylbutane will bioconcentrate in aquatic organisms. If released to the atmosphere, 2,3-dimethylbutane will exist as a vapor. Vapor-phase 2,3-dimethylbutane is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals with an estimated half-life of about 5.4 days. Vapor-phase 2,3-dimethylbutane is also degraded in the atmosphere by reaction with nitrate radicals with an estimated half-life of about 334 days. Exposure to 2,3-dimethylbutane will occur primarily through inhalation. (SRC)

2,3-Dimethylbutane's production and use as a high octane fuel and in organic synthesis(1) may result in its release to the environment through various waste streams(SRC). 2,3-Dimethylbutane is released into the atmosphere from auto, biomass combustion, and gasoline vapor emissions(2).

TERRESTRIAL FATE: Based on a recommended classification scheme(1), an estimated Koc value of 1700(SRC), determined from an experimental log Kow(2) and a recommended regression-derived equation(3), indicates that 2,3-dimethylbutane will have low mobility in soil(SRC). Volatilization of 2,3-dimethylbutane may be important from moist soil surfaces(SRC) given an estimated Henry's Law constant of 1.2 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure(4) and water solubility(5), and from dry soil surfaces(SRC) based on an experimental vapor pressure of 235 mm Hg(4). Insufficient data are available to determine the rate or importance of biodegradation of 2,3-dimethylbutane(SRC).

AQUATIC FATE: Based on a recommended classification scheme(1), an estimated Koc value of 1700(SRC), determined from an experimental log Kow(2) and a recommended regression-derived equation(3), indicates that 2,3-dimethylbutane would adsorb to suspended solids and sediment(SRC) in the water. 2,3-Dimethylbutane would volatilize from water surfaces based on an estimated Henry's Law constant of 1.2 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure(4) and water solubility(5). Estimated half-lives for a model river and model lake are 2.7 hours and 3.7 days, respectively(3,SRC). An estimated BCF value of 230(3,SRC), from an experimental log Kow(2), suggests that 2,3-dimethylbutane will bioconcentrate in aquatic organisms(SRC) according to a recommended classification scheme(6). Insufficient data are available to determine the rate or importance of biodegradation of 2,3-dimethylbutane(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,3-dimethylbutane, which has an experimental vapor pressure of 235 mm Hg at 25 °C(2) will exist as a vapor in the ambient atmosphere. Vapor-phase 2,3-dimethylbutane is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 5.4 days(3,SRC). Vapor-phase 2,3-dimethylbutane is also degraded in the atmosphere by reaction with nitrate radicals(4); the half-life for this reaction in air is estimated to be about 334 days(4,SRC).

Using the Clark oxygen electrode, a resting cell suspension of Corynebacterium (which used n-octane as sole carbon and energy source) oxidized 2,3-dimethylbutane with an activity of 43% that of n-octane (specific activity 78.5 ul oxygen/hour/mg cells)(1). 2,3-Dimethylbutane was not able to support the growth of any of the 32 microorganisms isolated from groundwater(2). Pure culture studies provide little insight into the biodegradation of 2,3-dimethylbutane in environmental samples(3,SRC).

The rate constant for the vapor-phase reaction of 2,3-dimethylbutane with photochemically produced hydroxyl radicals has been experimentally determined to be 6.2X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 5.4 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC). The rate constant for the vapor-phase reaction of 2,3-dimethylbutane with nitrate radicals has been experimentally determined to be 1.2X10-16 cu cm/molecule-sec at 25 °C(2). This corresponds to an atmospheric half-life of about 334 days at an atmospheric concentration of 2X10+8 NO3 radicals per cu cm(2,SRC).

An estimated BCF value of 230 was calculated for 2,3-dimethylbutane(SRC), using an experimental log Kow of 3.42(1) and a recommended regression-derived equation(2). According to a recommended classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms will be an important fate process(SRC).

The Koc of 2,3-dimethylbutane is estimated as approximately 1700(SRC), using an experimental log Kow of 3.42(1) and a regression-derived equation(2,SRC). According to a recommended classification scheme(3), this estimated Koc value suggests that 2,3-dimethylbutane has low mobility in soil(SRC).

The Henry's Law constant for 2,3-dimethylbutane is estimated as 1.2 atm-cu m/mole(SRC) from its experimental values for vapor pressure, 235 mm Hg(1), and water solubility, 22.5 mg/l(2). This value indicates that 2,3-dimethylbutane will volatilize rapidly from water surfaces(3,SRC). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec) is estimated as approximately 2.7 hours(3,SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec) is estimated as approximately 3.7 days(3,SRC). 2,3-Dimethylbutane's high vapor pressure(1) and high Henry's Law constant(1,2,SRC) indicate that volatilization from dry and moist soil surfaces may occur(SRC).

A study conducted in Atlanta found the average source profiles of 2,3-dimethylbutane in roadway, whole gas (average of six octanes), whole gas (87 octane), whole gas (89 octane), whole gas (92/93 octane), headspace gas (at 24 °C and average of six octanes), headspace gas (at 32 °C and average of six octanes), airport, and aircraft emissions were: 0.863, 0.88, 0.96, 0.83, 0.70, 1.49, 1.55, 0.55, and 0.332 ppbC%, respectively(1). A study conducted in Chicago found the average concentration of 2,3-dimethylbutane/2-methylpentane in regular fuel (87 octane), mid-grade (89 octane), premium (93 octane), hot soak, cold start, roadway, and petroleum refinery emissions to be 3.2, 2.34, 1.33, 4.62, 4.4, 3.21, and 2.62 wt%, respectively(2). Refueling emission profiles for 2,3-dimethylbutane/2-methylpentane were 2.58 and 2.26 wt% in the summer and winter, respectively and 4.17 and 3.2 wt% in Atlanta and Chicago respectively(2). The emission rate of 2,3-dimethylbutane is estimated to be 5 metric tons/day in a southern California mountain forest location impacted with urban photochemical smog(3). The profile for 2,3-dimethylbutane in gasoline engine exhaust (noncatalyst and catalyst equipped), unburned gasoline (whole and headspace vapors) was 0.6, 1.0, 1.1, and 1.1 wt%, respectively(4). 2,3-Dimethylbutane was identified in influent and effluent food refuse gas samples(5). The average 2,3-dimethylbutane contribution to emissions from 67 different vehicles was 0.6 wt% in Sydney, Australia(6). 2,3-Dimethylbutane content in moped exhaust with alkylate-based and reformate-based fuels was 1.2 and 1.5 wt% (alkylate: exhaust and fuel) and 0.48 and 0.6 (reformate: exhaust and fuel)(7).

In Southern California, the 2,3-dimethylbutane profile for various emissions for vehicle exhaust was 0.81, 0.89, 1.24, 0.00, 1.68, and 1.91 wt% for a 46 car study, 13 samples from the Caldecott Tunnel, cold start, stabilized, hot start, and from an older fleet, respectively(1). Gasoline emission profiles for 2,3-dimethylbutane are as follows: 4.99, 5.36, 3.34, 2.59, 2.32, 2.33, and 2.03 wt% for diurnal evaporative emissions (older fleet), hot soak evaporative emissions (older fleet), running loss (older fleet), summer liquid gas, winter liquid gas, summer gas headspace, and winter gas headspace, respectively(1). In oil field emissions (Tulsa, OK), 2,3-dimethylbutane was detected at average concentration of 24.5 ppbC and approximately 12 ppbC for two different samples(2). The concentration of 2,3-dimethylbutane in gasoline vapors from refueling cars at service stations ranged between 0.005 and 9.2 ppm(3).

URBAN/SUBURBAN: 2,3-Dimethylbutane was identified in downtown Los Angeles morning air at concns of 2-8 ppbv(1). A study of Washington, DC air identified 2,3-dimethylbutane in 62.5% of the samples at an average concn of 0.21 ppbv(2). 2,3-Dimethylbutane was identified in the air of the following industrial cities of the USSR: Leningrad, Tashkent, Baku, Tbilisi, Kemerovo, and Murmansk(3). 2,3-Dimethylbutane was also identified in the air of three large South African cities: Pretoria, Johannesburg, and Durban(4). 2,3-Dimethylbutane was identified in the air of Sydney, Australia at an average concn of 0.9 ppbv(5). 2,3-Dimethylbutane was identified in the air of Huntington Park, Los Angeles at 0.6 ppb (ground level, afternoon), 7.8 (groundlevel, morning), 2.1 (at 1500 ft, morning), and 0.1 ppb (at 2200 ft, morning)(6). A study conducted in the Riverside, CA area identified 2,3-dimethylbutane at concns of approximately 0.5, 0.2, 0.5, 0.7, and 0.6 ppb at five different sites(7). 2,3-Dimethylbutane was identified in the air of suburban, urban, and source dominated sites at the following average concns: 0.572 (219 samples), 0.6 (521 samples), and 0.666 ppbv (20 samples), respectively(8).

RURAL/REMOTE: 2,3-Dimethylbutane was identified in the air of six remote sites in North Carolina at the following median concns (ppb carbon): Roan Mountain, 0.1; Grandfather Mountain, 0.2; Linville Gorge, 0.1; Rich Mountain, 0.1; Boone Center, 3.1; and Boone Outskirts, 0.3(1).

The average concentration of 2,3-dimethylbutane in the air from gasoline vapors, to which petroleum industry workers may be exposed, for outside operators is 0.232 mg/cu m, for transport drivers is 0.958 mg/cu m, and for service attendants is 1.319 mg/cu m(1).

Occupational exposure to aliphatic hydrocarbons, such as 2,3-dimethylbutane(SRC), will occur primarily through inhalation(1).

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. Substances may be transported hot.

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Health: Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering.

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection.

For more DOT Emergency Guidelines (Complete) data for 2,3-DIMETHYLBUTANE (8 total), please visit the HSDB record page.

UN 2457; 2,3-Dimethylbutane

IMO 3.1; 2,3-Dimethylbutane

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Flammable Liquid