Dimethoxymethane

Dimethoxymethane, also known as formal dimethyl acetal (FDMA), is the acetal formed from formaldehyde and methanol, with the formula CH2(OCH3)2. It is a colorless, volatile liquid that is commonly used in organic synthesis and as a solvent. It is typically prepared by acid-catalyzed condensation of formaldehyde with methanol, with removal of water to drive the reaction toward acetal formation.

In organic synthesis, dimethoxymethane is used primarily as a reagent for protecting carbonyl groups and as a solvent. Under acid catalysis, it forms acetals with aldehydes and ketones, converting reactive carbonyls into dimethyl acetals that are stable under neutral and basic conditions. This protection can be reversed by hydrolysis under aqueous acidic conditions, enabling selective deprotection later in a synthesis sequence. The compound’s practical use as a solvent arises from its ability to dissolve a range of organic materials and its relatively low boiling point.

Production and handling: Dimethoxymethane is produced by the reaction of formaldehyde with methanol in the presence of an acid catalyst, followed by removal of water. It is flammable and should be stored in a tightly closed container away from heat and incompatible materials. In the presence of moisture or acids, it can hydrolyze to formaldehyde and methanol. Exposure via inhalation, ingestion, or skin/eye contact may be hazardous, so appropriate protective measures are advised. Spills should be contained and disposed of according to local regulations.