Dimethoxymethane

Not to be confused with dimethoxyethane.
Dimethoxymethane
Names
IUPAC name
Dimethoxymethane
Other names
Formal

Formaldehyde dimethyl ether
Methylal
Dimethylformal (DMFL)
Formaldehyde dimethylacetal
Methoxymethyl methyl ether

Methylene dimethyl ether
Identifiers
109-87-5 YesY
1697025
ChEBI CHEBI:48341 YesY
ChEMBL ChEMBL15537 YesY
ChemSpider 13837190 YesY
EC Number 203-714-2
100776
Jmol interactive 3D Image
MeSH Dimethoxymethane
PubChem 8020
RTECS number PA8750000
UN number 1234
Properties
C3H8O2
Molar mass 76.10 g·mol−1
Appearance Colorless liquid[1]
Odor Chloroform-like[1]
Density 0.8593 g cm−3 (at 20 °C)[1]
Melting point −105 °C (−157 °F; 168 K)[1][2]
Boiling point 42 °C (108 °F; 315 K)[1][2]
33% (20 °C)[3]
Vapor pressure 330 mmHg (20 °C)[3]
Hazards
Flammable (F)
Irritant (Xi)
R-phrases R11 R36/37/38
S-phrases S9, S16, S33
Flash point −18 °C (0 °F; 255 K)
Explosive limits 2.2%-13.8%[3]
Lethal dose or concentration (LD, LC):
5708 mg/kg (rabbit, oral)[4]
18000 ppm (mouse, 7 hr)
15000 ppm (rat)
18354 ppm (mouse, 7 hr)[4]
US health exposure limits (NIOSH):
TWA 1000 ppm (3100 mg/m3)[3]
TWA 1000 ppm (3100 mg/m3)[3]
2200 ppm[3]
Related compounds
Related Ethers
Dimethoxyethane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Dimethoxymethane, also called methylal, is a colorless flammable liquid with a low boiling point, low viscosity and excellent dissolving power. It has a chloroform-like odor and a pungent taste. It is the dimethyl acetal of formaldehyde. Dimethoxymethane is soluble in three parts water and miscible with most common organic solvents.

Synthesis and structure

It can be manufactured by oxidation of methanol or by the reaction of formaldehyde with methanol. In aqueous acid, it is hydrolyzed back to formaldehyde and methanol.

Due to the anomeric effect, dimethoxymethane has a preference toward the gauche conformation around the C–O bonds, instead of the anti conformation. Since it is one of the smallest molecules exhibiting this effect, which has great interest in carbohydrate chemistry, dimethoxymethane is often used for theoretical studies of the anomeric effect.

Applications

Industrially, it is primarily used as a solvent and in the manufacture of perfumes, resins, adhesives, paint strippers and protective coatings. Another application is as a gasoline-additive for increasing octane number.

Reagent in organic synthesis

Another useful application of dimethoxymethane is to protect alcohols with a MOM ether in organic synthesis.[5] This can be done using phosphorus pentoxide in dry dichloromethane or chloroform. This is a preferred method to using MOM-Cl. The MOM-ether can be removed using methanol in the presence of p-toluenesulfonic acid as an alternative to aqueous acid.

References

External links

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