Formaldehyde from CH3OH oxidation

Figure 65. Effect of dimensionless catalyst potential 77= FVwr/RTon the selectivity to CO2 and formaldehyde during CH3OH oxidation on Pt. Conditions as in Fig. 63. (Reprinted, with permission from Academic Press, from Ref. 41.)...

Figure 8.46. Effect of Pt catalyst dimensionless potential ]1=FUwr/RT on the kinetic constants of formation of formaldehyde (a) and CO2 (b) during CH3OH oxidation on Pt/YSZ Conditions as in Fig. 8.45.50 Reprinted with permission from Academic Press.

Hoare and Wellington (22) produced CH3O radicals from the photochemical (50° and 100°C.) and thermal (135°C.) decompositions of di-terf-butyl peroxide in the presence of 02. The initially formed tert-butoxy radicals decomposed to acetone plus methyl radicals, and the methyl radicals oxidized to methoxy radicals. Formaldehyde and CH3OH were products of the reaction the formation of the former was inhibited, and the latter was enhanced as the reaction proceeded. If the sole fate of CH3O were either... 

The over-all reduction of CO2 to CH4 is expected to be a spontaneous process that goes through the reduction levels of formate, formaldehyde, and methanol with only a limited, perhaps early requirement for activation by ATP. At the lowest reduction stages, extra ATP may even be generated. In the fermentation of methanol by M. barkeri which utilizes only the last reduction step for methane formation (Reaction 12) somewhat more than 1 mole of ATP appears to be generated for each mole of CH3OH oxidized to CO2, judging from cell yields (14). 

Figure 13.3 Potentiodynamic electrooxidation of (a) formic acid, (b) formaldehyde, and (c) methanol on a Pt/Vulcan thin-film electrode (7 xgpt cm, geometric area 0.28 cm ) in 0.5 M H2SO4 solution containing 0.1 M HCOOH (a), HCHO (b), or CH3OH (c). The potential scan rate was 10 mV s and the electrolyte flow rate was 5 p-L s at room temperature). The top panels show the faradaic current (solid lines), the partial currents for Ci oxidation to CO2 (dashed lines) and for formic acid formation (dash-dotted line), calculated from the respective ion currents, and the difference between the measured faradaic current and the partial current for CO2 oxidation (formic acid oxidation (a), formaldehyde oxidation (b)), or the difference between faradaic current and the sum of the partial currents for CO2 formation and formic acid oxidation (methanol oxidation, (c)) (dotted line). The solid lines in the lower panels in...

Dehydrogenation. The removal of one or more hydrogen atoms from a molecule by chemical means, as in the conversion of alcohols to aldehydes. For example, methanol (CH3OH) can be oxidized to formaldehyde (HCHO) plus H2. ... 

Methanol disproportionation includes two sites of A/xNa" generation (1) Methanol reduction generates a secondary AftNa from a primary A/IH" by the activity of the Na /H antiporter. This was concluded from the finding that CH4 formation from H2/CH3OH in Methanosarcina barkeri was coupled with Na extrusion, which was sensitive to Na /H antiporter inhibitors and protonophores [108]. (2) The oxidation of methylene-H4MPT to CO2 and 4[H] is coupled with the generation of a primary A/INa as indicated from the fact that Na translocation associated with formaldehyde conversion to CO2 and 2H2 was not sensitive towards Na /H antiporter inhibitors and protonophores [105]. 

Oxidation. Catalyst preparation procedures determine catalyst structures and consequent catalytic performance. The activity of combinations of oxides is often quite different from those of the individual oxides. For example, the capability of FejOj, the catalyst used to oxidize CH3OH to formaldehyde, to promote complete oxidation is nearly absent in iron(III) molybdate, Fe2(Mo04>3. ... 

Formaldehyde occurs naturally in the atmosphere at a concentration of about 10 parts per billion (0.000 001%) partly as a by-product of plant and animal metabolism, and partly as a product of the reaction of sunlight with methane (CH4), a much more abundant component of the air. At such low concentrations, it is not a natural source of the compound for commercial or industrial uses and is produced instead by the oxidation of methanol (methyl alcohol CH3OH) or gases extracted from petroleum (such as methane) over a catalyst of silver, copper, or iron with molybdenum oxide. 

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