Formula

CH₃ - O - C (CH₃)₃

Description

Methyl Tertiary Butyl Ether (MTBE) is a colorless liquid with a characteristic mild odor. Its principal characteristics are miscibility with gasoline, low blending vapor pressure and distillation properties. MTBE is slightly soluble in water without phase separation problems. Compared to other oxygenated fuels, it has lower blending density, lower blending vapor pressure and no corrosion problems.

Properties

Parameter	Unit	Quantity
Specific gravity	°C at 20°C/20°C	0.74
IBP	°C at 1.0 atm	50.5 min
FBP	°C at 1.0 atm	74.5 max
CAS number	1634-04-4
IUPAC name	2-Methoxy-2-methylpropane

Specifications

Parameter	Unit	Quantity	Test Method
Purity	wt %	98 min	ASTM D-5441
C4-hydrocarbons	wt %	0.5 max	ASTM D-5441
C5-hydrocarbons	wt %	1 max	ASTM D-5441
Methanol	wt %	0.7 max	ASTM D-5441
Ter-butyl alcohol	wt %	0.6 max	ASTM D-5441
Di-isobutene	wt %	0.6 max	ASTM D-5441
Water	ppm	500 max	ASTM D-1364

Note:
ASTM : American Society for Testing and Materials

Hazards and safety

MTBE’s toxicological effect is largely similar to that of lead-free gasoline. It has no special toxic effects, symptoms or hygienic requirements.

Parameter	Unit	Quantity
Flash point	°C	-26
Flammable limits	vol % in air	1.6-84
Ignition temperature	°C	430
UN or ID No.		2398

Applications

MTBE is used mainly as a high octane gasoline blending component. It replaces lead compounds and provides good anti-knock characteristics.

Storage and handling

MTBE can be shipped or stored in conventional fuel tanks. Nitrogen purging is strongly recommended in case of loading vessels in hot weather. Acid or iron rust contamination should be avoided. MTBE does not form peroxide compounds on long period storage.

MTBE is shipped in fuel tanks (similar to those used for gasoline). Each shipping tank or container must bear the label “Flammable Liquid”.