Molecular Structure:

Molecular Formula: C₅H₁₂O
Molecular Weight: 88.1482
IUPAC Name: 2-Methoxy-2-methylpropane
Synonyms of tert-Butyl methyl ether (CAS NO.1634-04-4): 2-Methoxy-2-methylpropane ; 2-Methyl-2-methoxypropane ; 4-01-00-01615 (Beilstein Handbook Reference) ; BRN 1730942 ; CCRIS 7596 ; EINECS 216-653-1 ; Ether, tert-butyl methyl ; HSDB 5847 ; MTBE ; Methyl 1,1-dimethylethyl ether ; Methyl tert-butyl ether ; Methyl tertiary-butyl ether ; Propane, 2-methoxy-2-methyl- ; t-Butyl methyl ether ; tert-Butyl methyl ether
CAS NO: 1634-04-4
Classification Code: Air Pollutants ; Carcinogens ; Environmental Pollutants ; Noxae ; Reproductive Effect
Melting point: -110 °C 
Index of Refraction: 1.375
Molar Refractivity: 26.92 cm³
Molar Volume: 117.4 cm³
Surface Tension: 19.1 dyne/cm
Density: 0.75 g/cm³
Enthalpy of Vaporization: 28.58 kJ/mol
Boiling Point: 55.2 °C at 760 mmHg
Vapour Pressure of tert-Butyl methyl ether (CAS NO.1634-04-4): 251 mmHg at 25°C

 tert-Butyl methyl ether (CAS NO.1634-04-4) is almost exclusively used as a fuel component in motor gasoline. It has excited considerable interest because it is a good octane enhancer for gasoline (it blends as if it had a research octane number of 115 to 135). It also offers a method of selectively removing iso-butylene from a mixed C₄ stream, thus enabling the recovery of high-purity butene-1. Furthermore, it can be isolated, then cracked to yield highly pure iso-butylene and methanol. It is also used in organic chemistry as a relatively inexpensive solvent with properties comparable to diethyl ether but with a higher boiling point and lower solubility in water. It is also used medically to dissolve gallstones.

The reaction for making tert-Butyl methyl ether proceeds quickly and highly selectively by reacting a mixed butene-butane fraction with methyl alcohol in the liquid phase on a fixed bed of an acidic ion-exchange resin catalyst.
          CH₃OH + (CH₃)₂C=CH₂ → CH₃OC(CH₃)₃
Reactor effluent is distilled, giving tert-Butyl methyl ether of 99% purity. A few precent of iso-butylene remains unchanged and can be scavenged by use of a second unit.

Community Right-To-Know List. Reported in EPA TSCA Inventory.

Hazard Codes of tert-Butyl methyl ether (CAS NO.1634-04-4): Xn,F,XiT
Risk Statements: 36/37/38-40-11-39-23/24/25
R36/37/38: Irritating to eyes, respiratory system and skin. 
R40: Limited evidence of a carcinogenic effect. 
R11: Highly flammable. 
R39: Danger of very serious irreversible effects. 
R23/24/25: Toxic by inhalation, in contact with skin and if swallowed.
Safety Statements: 9-16-24-45-36/37 
S9: Keep container in a well-ventilated place. 
S16: Keep away from sources of ignition. 
S24: Avoid contact with skin. 
S45: In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S36/37: Wear suitable protective clothing and gloves.
RIDADR: UN 2398 3/PG 2
WGK Germany: 3
RTECS: KN5250000
F: 3-10
HazardClass: 3
PackingGroup: II
Hazardous Substances Data: 1634-04-4(Hazardous Substances Data)
Poison by intravenous route. Slightly toxic by ingestion and inhalation. Flammable when exposed to heat or flame. When heated to decomposition it emits acrid smoke and irritating fumes. See also ETHERS.

ACGIH TLV: TWA 50 ppm; Confirmed Animal Carcinogen with Unknown Revelance to Humans
DOT Classification:  3; Label: Flammable Liquid

For occupational chemical analysis use NIOSH: tert-Butyl methyl ether (MTBE) 1615.