General Description
Methyl trifluoromethane sulfonate is a brown liquid. Insoluble in water. (NTP, 1992) This material is a very reactive methylating agent, also known as methyl triflate.
Reactivity Profile
METHYL TRIFLUOROMETHANE SULFONATE(333-27-7) is sensitive to heat. . Esters react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides.
Air & Water Reactions
Highly flammable. Insoluble in water.
Health Hazard
ACUTE/CHRONIC HAZARDS: When heated to decomposition this compound emits toxic fumes.
Fire Hazard
This chemical is combustible.
Chemical Properties
clear colourless to yellow liquid
Application
Methyl trifluoromethanesulfonate, a methylating agent, is commonly used for the pre-methylation of polysaccharides under mild basic conditions.
In the determination of polysulfides, zerovalent sulfur in sulfide-rich water wells, and polysulfide species in electrolyte of a lithium–sulfur battery using chromatography-based techniques.
In reactions with potassium enolates.
For the conversion of amines to methyl ammonium triflates.
Additionally, methyl trifluoromethanesulfonate has been utilized in the production of 2-Benzyloxy-1-methylpyridinium trifluoromethanesulfonate.
Toxicology
Methyl trifluoromethanesulfonate is extremely hazardous. All possible precautions should be taken to avoid inhalation or absorption through the skin. This material is extremely destructive to the tissue of the mucous membranes and upper respiratory tract, eyes, and skin. Inhalation may be fatal as a result of spasm, inflammation, and edema of the larynx and bronchi, chemical pneumonitis, and pulmonary edema. Use in a fume hood. Although there has yet to be a reported human fatality, several cases were reported for methyl fluorosulfonate (LC50 (rat, 1 h) = 5 ppm), and methyl triflate is expected to have similar toxicity based on available evidence.
Synthesis
Methyl trifluoromethanesulfonate is commercially available, however it may also be prepared in the laboratory by treating dimethyl sulfate with triflic acid.
CF3SO2OH + (CH3O)2SO2 → CF3SO2OCH3 + CH3OSO2OH
Purification Methods
Methyl trifluoromethanesulfonate (methyl triflate) [333-27-7] M 164.1, b 97 -97.5o/736mm, 9 9o/~760mm, 100-102o/~760mm, d 4 1.496, n D 1.3238. It is a strong methylating agent but is corrosive and POISONOUS. Fractionate it carefully and collecting the middle fraction (use an efficient fume cupboard) and keep away from moisture. It is a POWERFUL ALKYLATING AGENT and a strong IRRITANT. [IR: Gramstad & Haszeldine J Chem Soc 173 1956 , J Chem Soc 4069 1957 .] Trifluoromethanesulfonic acid (triflic acid) [1493-13-6] M 151.1, boils higher (b 162o/atm), has a pKa of 3.10, and is TOXIC and hygroscopic. [Hansen J Org Chem 30 4322 1965, Kurz & El-Nasr J Am Chem Soc 104 5823 1982, Beilstein 3 IV 34.]
