Dimethoxymethane
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| Names | |
|---|---|
| IUPAC name
Dimethoxymethane | |
| Other names
Formal Formaldehyde dimethyl ether | |
| Identifiers | |
| 3D model (JSmol) |
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| 1697025 | |
| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.003.378 |
| EC Number | 203-714-2 |
| 100776 | |
| MeSH | Dimethoxymethane |
| PubChem CID |
|
| 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] |
| -47.3·10−6 cm3/mol | |
| Hazards | |
| EU classification (DSD) (outdated) |
Flammable (F) Irritant (Xi) |
| R-phrases (outdated) | R11 R36/37/38 |
| S-phrases (outdated) | S9, S16, S33 |
| Flash point | −18 °C (0 °F; 255 K) |
| Explosive limits | 2.2%-13.8%[3] |
| Lethal dose or concentration (LD, LC): | |
| LD50 (median dose) |
5708 mg/kg (rabbit, oral)[4] |
| LC50 (median concentration) |
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)[3] |
| REL (Recommended) |
TWA 1000 ppm (3100 mg/m3)[3] |
| IDLH (Immediate danger) |
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). | |
 verify (what is  ?) | |
| 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
- 1 2 3 4 5 Merck Index, 11th Edition, 5936
- 1 2 International Chemical Safety Card 1152
- 1 2 3 4 5 6 "NIOSH Pocket Guide to Chemical Hazards #0396". National Institute for Occupational Safety and Health (NIOSH).
- 1 2 "Methylal". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).
- ↑ Martin Berliner and Katherine Belecki. "Synthesis of Alpha-Halo Ethers from Symmetric Acetals and in situ Methoxymethylation of an Alcohol". Org. Synth. 84: 102.; Coll. Vol., 11, p. 934
External links
- "NIOSH Pocket Guide to Chemical Hazards #0396". National Institute for Occupational Safety and Health (NIOSH).