Print
Chemical Datasheet

METHYL TERT-BUTYL ETHER

3 - Flammable liquid

Chemical Identifiers

CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 1634-04-4   (METHYL TERT-BUTYL ETHER)
  • 2398
  • Flammable Liquid
  • MBE
NIOSH Pocket Guide International Chem Safety Card
none
  • METHYL TERT-BUTYL ETHER
NFPA 704
data unavailable
General Description
A colorless liquid with a distinctive anesthetic-like odor. Vapors are heavier than air and narcotic. Boiling point 131°F. Flash point 18°F. Less dense than water and miscible in water. Used as a octane booster in gasoline.

Hazards

Reactivity Alerts
Air & Water Reactions
Highly flammable. Oxidizes readily in air to form unstable peroxides that may explode spontaneously [Bretherick 1979. p.151-154, 164]. A mixture of liquid air and diethyl ether exploded spontaneously [MCA Case History 616. 1960].
Fire Hazard
Special Hazards of Combustion Products: May contain irritating and toxic gases.

Behavior in Fire: May be ignited by heat, sparks or flames. Containers may explode in heat of fire. Vapor explosion hazard indoors, outdoors, or in sewers. (USCG, 1999)
Health Hazard
INHALATION: May cause dizziness or suffocation. Contact may irritate or burn eyes or skin. May be harmful if swallowed. (USCG, 1999)
Reactivity Profile
Ethers, such as METHYL TERT-BUTYL ETHER, can act as bases. They form salts with strong acids and addition complexes with Lewis acids. The complex between diethyl ether and boron trifluoride is an example. Ethers may react violently with strong oxidizing agents. In other reactions, which typically involve the breaking of the carbon-oxygen bond, ethers are relatively inert.
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

No information available.

Response Recommendations

Isolation and Evacuation
Excerpt from 127 Polymerizable warning [Flammable Liquids (Water-Miscible)]:

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 car or tank truck 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, 2020)
Firefighting
Excerpt from 127 Polymerizable warning [Flammable Liquids (Water-Miscible)]:

CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient. CAUTION: For fire involving UN1170, UN1987 or UN3475, alcohol-resistant foam should be used. CAUTION: Ethanol (UN1170) can burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.).

SMALL FIRE: Dry chemical, CO2, water spray or alcohol-resistant foam.

LARGE FIRE: Water spray, fog or 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 OR CAR/TRAILER LOADS: 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. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2020)
Non-Fire Response
Excerpt from 127 Polymerizable warning [Flammable Liquids (Water-Miscible)]:

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, 2020)
Protective Clothing
Wear goggles, self-contained breathing apparatus, rubber gloves, boots and overclothing. (USCG, 1999)
DuPont Tychem® Suit Fabrics
Normalized Breakthrough Times (in Minutes)
Chemical CAS Number State QS QC SL C3 TF TP RC TK RF
Methoxy 2-methylpropane, 2- 1634-04-4 Liquid >480 >480 >480 >480 >480 >480 >480
Methyl tert-butyl ether 1634-04-4 Liquid >480 >480 >480 >480 >480 >480 >480
> indicates greater than.

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

First Aid
INHALATION: Move victim to fresh air; call emergency medical care. If not breathing, give artificial respiration. If breathing is difficult, give oxygen.

EYES OR SKIN: Flush with running water for at least 15 minutes; hold eyelids open if necessary. Remove and isolate contaminated clothing and shoes at the site. Keep victim quiet and maintain normal body temperature.

INGESTION: If victim is unconscious or having convulsions, do nothing except keep victim warm. (USCG, 1999)

Physical Properties

Chemical Formula:
  • C5H12O
Flash Point: -14°F (USCG, 1999)
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point: -164.2°F (USCG, 1999)
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: 0.7405 at 68°F (USCG, 1999) - Less dense than water; will float
Boiling Point: 131.4°F at 760 mmHg (USCG, 1999)
Molecular Weight: 88.15 (USCG, 1999)
Water Solubility: data unavailable
Ionization Energy/Potential: data unavailable
IDLH: data unavailable

AEGLs (Acute Exposure Guideline Levels)

Interim AEGLs for Methyl-tertiary-butyl ether (MTBE) (1634-04-4)
Exposure Period AEGL-1 AEGL-2 AEGL-3
10 minutes 50 ppm 1400 ppm 13000 ppm 2-flame icon indicates value is 50-99% of LEL. Extreme safety consideration against explosions must be taken into account.
30 minutes 50 ppm 800 ppm 7500 ppm 1-flame icon indicates value is 10-49% of LEL. Safety consideration against explosions must be taken into account.
60 minutes 50 ppm 570 ppm 5300 ppm 1-flame icon indicates value is 10-49% of LEL. Safety consideration against explosions must be taken into account.
4 hours 50 ppm 400 ppm 2700 ppm 1-flame icon indicates value is 10-49% of LEL. Safety consideration against explosions must be taken into account.
8 hours 50 ppm 400 ppm 1900 ppm 1-flame icon indicates value is 10-49% of LEL. Safety consideration against explosions must be taken into account.
Lower Explosive Limit (LEL) = 16000
1-flame icon indicates value is 10-49% of LEL. Safety consideration against explosions must be taken into account.
2-flame icon indicates value is 50-99% of LEL. Extreme safety consideration against explosions must be taken into account.
(NAC/NRC, 2023)

ERPGs (Emergency Response Planning Guidelines)

Chemical ERPG-1 ERPG-2 ERPG-3
Methyl tert-Butyl Ether (MTBE) (1634-04-4) 50 ppm star-in-circle icon indicates that odor should be detectable near ERPG-1. 1000 ppm 5000 ppm 1-flame icon indicates value is 10-49% of LEL. LEL = 16000 ppm
star-in-circle icon indicates that odor should be detectable near ERPG-1.
1-flame icon indicates value is 10-49% of LEL.
(AIHA, 2022)

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Methyl tert-butyl ether; (MTBE) (1634-04-4) 50 ppm 570 ppm 5300 ppm 1-flame icon indicates value is 10-49% of LEL. LEL = 16000 ppm
1-flame icon indicates value is 10-49% of LEL.
(DOE, 2018)

Regulatory Information

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code
EPCRA 302
EHS TPQ
EPCRA 304
EHS RQ
CERCLA RQ EPCRA 313
TRI
RCRA
Code
CAA 112(r)
RMP TQ
Methyl tert-butyl ether 1634-04-4 1000 pounds 313

(EPA List of Lists, 2022)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

No regulatory information available.

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

Alternate Chemical Names