Prepd commercially by catalytic vapor phase oxidation of methanol using air as the oxidizing agent and heated silver, copper, alumina, or coke as
catalysts. Process using molybdenum iron oxide catalyst: Allyn et al., U.S. pat. 2,812,309 (1957) and U.S. pat. 2,849,492 (1958 to Reichhold Chem.). Prepn of stable formaldehyde by heating low molecular polyoxymethylenes with P2O5: Ger. pat. 1,070,611 (1959 to BASF). Mfg processes: Faith, Keyes Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 422-429. Prepn of semicarbazone: M. Pomerantz et al., J. Org. Chem. 47, 2217 (1982).
Though it's not a watched precursor...