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CHEMINFO Record Number: 260
CCOHS Chemical Name: 3,3-Dimethylpentane

Dimethylpentane (non-specific name)

CAS Registry Number: 562-49-2
UN/NA Number(s): 1206
EU EINECS/ELINCS Number: 209-230-8
Chemical Family: Saturated aliphatic hydrocarbon / alkane / heptane isomer
Molecular Formula: C7-H16
Structural Formula: CH3-CH2-C(CH3)2-CH2-CH3


Appearance and Odour:
Colourless liquid with a gasoline-like odour.

Odour Threshold:
Not available

Warning Properties:
Insufficient information

3,3-Dimethylpentane is one of the chemical forms (isomers) of heptane (C7- H16). It has many similarities (properties and hazards) to other heptanes. Some information in this record is given specifically for 3,3-dimethylpentane. Specific information is available for the related isomer n-heptane (CHEMINFO Record Number 255e).

Uses and Occurrences:
Ingredient in gasoline and aviation fuels; solvent; and organic synthesis.


Colourless liquid, gasoline-like odour. EXTREMELY FLAMMABLE LIQUID AND VAPOUR. Can accumulate static charge. Vapour is heavier than air and may spread long distances. Distant ignition and flash back are possible. Liquid can float on water and may travel to a distant location or spread fire. Central nervous system depressant. High vapour concentrations may cause headache, nausea, dizziness, drowsiness, confusion, unconsciousness and death. Aspiration hazard. Swallowing or vomiting of the liquid may result in aspiration into the lungs.


Effects of Short-Term (Acute) Exposure

There is no specific information for 3,3-dimethylpentane; however it is closely related to n-heptane which has very low acute toxicity. Exposure to high concentrations is required to cause the primary effect which is depression of the central nervous system. Symptoms include headache, nausea, dizziness, confusion or unconsciousness leading to death. Nose and throat irritation may occur at high vapour concentrations.(6)

Skin Contact:
There is no specific information for 3,3-dimethylpentane. The related material, n-heptane, was not irritating on brief skin contact but produced mild irritation after 1 hour. Blisters occurred after 5 hours of direct contact with the skin covered to prevent evaporation.(6)

Eye Contact:
3,3-Dimethylpentane and the related n-heptane are not known as eye irritants. Based on reports of mild skin irritation with n-heptane, it would be expected that direct eye contact with 3,3-dimethylpentane may cause mild irritation but not injury. Concentrated vapour may also be expected to cause eye irritation.(6)

There is no specific information for 3,3-dimethylpentane. Animal toxicity information for n-heptane showed very low toxicity if ingested. Large doses would be required to produce symptoms of central nervous system depression as described for "Inhalation" above.
Based on its physical properties, 3,3-dimethylpentane can be easily aspirated following ingestion or vomiting. This could result in potentially fatal lung damage (pulmonary edema).
Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

No effects following long-term exposure have been reported in humans for 3,3-dimethylpentane or the related material, n-heptane.
SKIN: There is no specific information for 3,3-dimethylpentane. The related material, n-heptane is a defatting agent and prolonged or repeated contact can cause irritation and dermatitis (inflammation, redness and swelling). Similar effects would be expected with 3,3-dimethylpentane.
EFFECTS ON NERVOUS SYSTEM: There is no specific information for 3,3-dimethylpentane. Nerve damage has been reported for workers exposed to petroleum solvents containing mixtures of chemicals including the related material, n-heptane.(1,6) However animal studies and human metabolic studies indicate that n-heptane probably does not have these effects. While it is not possible to rule out neurotoxic effects occurring from 3,3-dimethylpentane exposure, they would not be expected from occupational exposure.


There is no human or animal information available.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has not assigned a carcinogenicity designation to this chemical.

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
There is no human or animal information available.

Reproductive Toxicity:
There is no human or animal information available.

There is no information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
There is no information available. Not expected to accumulate as the related material, n-heptane, is readily metabolized and excreted.


This product is flammable. Take proper precautions (e.g. remove any sources of ignition). Remove source of contamination or move victim to fresh air. If breathing has stopped, trained personnel should begin artificial respiration or, if the heart has stopped, cardiopulmonary resuscitation (CPR) immediately. Obtain medical attention immediately.

Skin Contact:
Remove contaminated clothing, shoes and leather goods (e.g. watchbands, belts). Gently blot or brush away excess chemical quickly. Wash gently and thoroughly with water and non-abrasive soap for at least 5 minutes or until the chemical is removed. If irritation persists, obtain medical advice immediately.

Eye Contact:
Quickly and gently blot or brush away excess chemical. Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 5 minutes or until the chemical is removed, while holding the eyelid(s) open. Obtain medical advice immediately.

Never give anything my mouth if victim is rapidly losing consciousness, is unconscious or convulsing. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz.) of water. If vomiting occurs naturally, have victim lean forward to reduce risk of aspiration. Repeat administration of water. Obtain medical attention immediately.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest). Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instances of inhalation or skin contact. All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.


Flash Point:
-6 deg C (20 deg F) (closed cup) (2)

Lower Flammable (Explosive) Limit (LFL/LEL):
Not available

Upper Flammable (Explosive) Limit (UFL/UEL):
Not available

Autoignition (Ignition) Temperature:
Not available

Sensitivity to Mechanical Impact:
Probably not sensitive. Stable material.

Sensitivity to Static Charge:
Specific information is not available. By comparison to related hydrocarbons, 3,3-dimethylpentane may accumulate static charge by flow or agitation, since hydrocarbons have low electrical conductivities. Vapour may be ignited by static discharge.

Combustion and Thermal Decomposition Products:
Carbon monoxide and carbon dioxide.(2)

Fire Hazard Summary:
Extremely flammable liquid. Material will readily ignite at room temperature. Vapour is heavier than air and may travel a considerable distance to a source of ignition and flash back to a leak or open container. Liquid can float on water and may travel to distant locations and/or spread fire. Vapour can accumulate in confined spaces, resulting in a toxicity and flammability hazard. During a fire, irritating/toxic gases may be generated. Containers may explode in the heat of the fire.

Extinguishing Media:
Carbon dioxide, dry chemical powder, alcohol foam or polymer foam.(2) Water may be ineffective because it may not cool 3,3-dimethylpentane below its flash point. Fire fighting foams are the extinguishing agent of choice for most flammable liquid fires.

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or protected location. Approach fire from upwind to avoid hazardous vapours and toxic decomposition products.
Stop leak before attempting to stop the fire. If the leak cannot be stopped, and if there is no risk to the surrounding area, let the fire burn itself out. If the flames are extinguished without stopping the leak, vapours could form explosive mixtures with air and reignite.
Water can extinguish the fire if used under favourable conditions and when hose streams are applied by experienced firefighters trained in fighting all types of flammable liquid fires.
Containers may rupture in the heat of the fire. Isolate materials not yet involved in the fire and protect personnel. Move containers from fire area if this can be done without risk. Otherwise, fire-exposed containers or tanks should be cooled by application of hose streams and this should begin as soon as possible (within the first several minutes) and should concentrate on any unwetted portions of the container. If this is not possible, use unmanned monitor nozzles and immediately evacuate the area.
If a leak or spill has not ignited, use water spray in large quantities to disperse the vapours, to protect personnel attempting to stop a leak and to flush spills away from ignition sources. Solid streams of water may be ineffective and spread material.
For a massive fire in a large area, use unmanned hose holder or monitor nozzles; if this is not possible withdraw from fire area and allow fire to burn. Stay away from ends of tanks. Withdraw immediately in case of rising sound from venting safety device or any discolouration of tank due to fire.
Firefighters may enter the area if positive pressure self-contained breathing appraratus (MSHA/NIOSH approved or equivalent) and full Bunker Gear is worn.


NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


Molecular Weight: 100.2 (5)

Conversion Factor:
1 ppm = 4.09 mg/m3; 1 mg/m3 = 0.245 ppm at 25 deg C (calc.)

Physical State: Liquid
Melting Point: -135 deg C (-211 deg F) (2)
Boiling Point: 86 deg C (187 deg F) (2)
Relative Density (Specific Gravity): 0.693 at 20 deg C (water = 1) (2)
Solubility in Water: Insoluble
Solubility in Other Liquids: Soluble with most organic solvents.
Coefficient of Oil/Water Distribution (Partition Coefficient): Not available
pH Value: Not applicable
Vapour Density: 3.5 (air = 1)
Vapour Pressure: Not available
Saturation Vapour Concentration: Not available
Evaporation Rate: Not available
Critical Temperature: Not available

Other Physical Properties:
SAYBOLT UNIVERSAL VISCOSITY: Probably less than 32 seconds (based on closely-related isomer) (5)


Normally stable

Hazardous Polymerization:
Does not occur

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.

STRONG OXIDIZING AGENTS (e.g. peroxides, nitrates and perchlorates) - May react violently. Increased risk of fire and explosion.

Hazardous Decomposition Products:

Conditions to Avoid:
Heat, open flames, static discharge, sparks and other ignition sources.

Corrosivity to Metals:
Not corrosive


No reports of animal studies with exposures to 3,3-dimethylpentane were located. The related material, n-heptane has very low toxicity by any route of exposure (oral, dermal or inhalation). Large exposures were required to produce depression of the central nervous system (incoordination, coma, death) in short-term studies. No major toxic effects were reported in long-term animal studies with n-heptane.


Selected Bibliography:
(1) n-Heptane. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. American Conference of Governmental Industrial Hygienists, 1991. p. 734-735
(2) The Sigma-Aldrich library of chemical safety data. Edition II. Vol. 1. Sigma-Aldrich Corporation, 1988. p. 1400B
(3) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(4) NIOSH pocket guide to chemical hazards. NIOSH, June, 1994. p. 156-157
(5) Cavender, F. Aliphatic hydrocarbons. In: Patty's industrial hygiene and toxicology. 4th ed. Vol. II. Toxicology. Part B. Edited by G.D. Clayton et al. John Wiley and Sons, 1994. p. 1223, 1226-1227, 1235-1236.
(6) Low, L.K., et al. n-Heptane. In: Ethel Browning's toxicity and metabolism of industrial solvents. Vol. 1. Hydrocarbons. 2nd ed. Elsevier Science Publishers, 1987. p. 297-306
(7) European Communities. Commission Directive 98/98/EC. December 15, 1998

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.

Review/Preparation Date: 1997-03-04

Revision Indicators:
US transport 1998-03-01
Resistance of materials 1998-06-01
TLV comments 1998-08-01
EU Class 2000-04-01
EU Risk 2000-04-01
EU Safety 2000-04-01
EU Comments 2000-04-01
Bibliography 2000-04-01
Carcinogenicity 2003-06-16
OSHA hazcom 2003-06-16
Resistance of materials for PPE 2004-03-28

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