Molybdate and tungstate catalysts for methanol oxidation

Conference · Thu Sep 01 04:00:00 EDT 1983 · Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States)

OSTI ID:6646513

Machiels, C J; Chowdhry, U; Sleight, A W

The most selective catalysts for the oxidation of methanol to formaldehyde are molybdates. In many commercial processes, a mixture of ferric molybdate and molybdenum trioxide is used. Ferric molybdate has often been reported to be the major catalytically active phase with the excess molybdenum trioxide added to improve the physical properties of the catalyst and to maintain an adequate molybdenum concentration under reactor conditions. In some cases, a synergistic effect is claimed, with maximum catalytic activity for a mixture with an Fe/Mo ratio of 1.7. Aging of a commercial catalyst has been studied using a variety of analytical techniques and it was concluded that deactivation can largely be accounted for by loss of molybdenum from the catalyst surface. In this laboratory, the mechanism of methanol oxidation over molybdate and tungstate catalysts has been studied using a variety of techniques. Steady state and pulse reactor studies using labeled reactants have established that methanol conversion to formaldehyde is a redox reaction with lattice oxygen being involved. A kinetic isotope effect has recently been reported and it shows that the rate limiting step in the reaction sequence is removal of a hydrogen from the methyl group. Fourier transform infrared studies have shown that a methoxy CH/sub 3/O group is a surface intermediate during the reaction and temperature programmed reaction studies have elucidated the nature of surface reactions and have allowed estimation of the number of catalytically active sites on powder surfaces.

• Research Organization: Central Research and Development Department, Experimental Station, E.I. du Pont de Nemours and Company, Wilmington, Delaware
• OSTI ID: 6646513
• Report Number(s): CONF-830814-
• Conference Information: Journal Name: Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States) Journal Volume: 28:5
• Country of Publication: United States
• Language: English

Related Subjects

090210* -- Alcohol Fuels-- Properties-- (1976-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALCOHOLS
ALDEHYDES
BENCH-SCALE EXPERIMENTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
FORMALDEHYDE
HYDROXY COMPOUNDS
KINETICS
METHANOL
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PRODUCTION
REACTION KINETICS
REDOX REACTIONS
TEMPERATURE EFFECTS
TRANSITION ELEMENT COMPOUNDS