formaldehyde - Sciencemadness Dot Org

FORMALDEHYDE
Production of Formaldehyde from Methanol
Reaction Mechanism. The formation of formaldehyde by the passage
of methanol and air over a heated metallic catalyst was first believed to be
a gas-phase oxidation process, as indicated in the following equation:
CH3OH + £0« -> CH30 -f H20 + 3S kcal
Fig. 2. August Wilhelm von Hofmarm (1818-1892), who first prepared formaldehyde
frcm methanol, is shown above in a portrait painted by Angeli in February,
1S90. Hofmann's preparation clearly established both the structure and identity of
formaldehyde as the first member of the aldehyde group.
Print reproduced from 1902 Sonderheft, Berichte der Deutschen Chemischen
Geselschaft.
However, mechanism studies have since demonstrated that it is either a
dehydrogenation, followed by oxidation of hydrogen to the extent that
oxygen is present in the gaseous mixture 22 ' 32 , as shown below
CH3OH ^ CH20 + Ha -20 kcal
H4 + |03 -• HaO + 58 kcal
^or a combination of the dehydrogenation and oxidation reactions. Oxida-
. tion reactions supply heat to make the process self-sustaining and are also