Dimethoxymethane

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Not to be confused with dimethoxyethane.
Dimethoxymethane
Structural formula of dimethoxymethane
Ball and stick model of dimethoxymethane
Names
IUPAC name
Dimethoxymethane
Other names
Formal

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

Methylene dimethyl ether
Identifiers
3D model (Jmol)
1697025
ChEBI
ChemSpider
ECHA InfoCard 100.003.378
EC Number 203-714-2
100776
MeSH Dimethoxymethane
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][3]
Boiling point 42 °C (108 °F; 315 K)[1][3]
33% (20 °C)[2]
Vapor pressure 330 mmHg (20 °C)[2]
-47.3·10−6 cm3/mol
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%[2]
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):
PEL (Permissible)
TWA 1000 ppm (3100 mg/m3)[2]
REL (Recommended)
TWA 1000 ppm (3100 mg/m3)[2]
IDLH (Immediate danger)
2200 ppm[2]
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[edit]

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[edit]

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[edit]

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[edit]

External links[edit]