Formaldehyde anodic oxidation

An interesting study examined the anodic oxidation of EDTA at alkaline pH on a smooth platinum electrode (Pakalapati et al. 1996). Degradation was initiated by removal of the acetate side chains as formaldehyde, followed by deamination of the ethylenediamine that formed glyoxal and oxalate. Oxalate and formaldehyde are oxidized to CO2, and adsoption was an integral part of the oxidation. 

Beltowska-Brzezinska M, Heitbaum J. 1985. On the anodic oxidation of formaldehyde on Pt, An and Pt/Au-alloy electrodes in alkaline solution. J Electroanal Chem 183 167-181. 

Sidheswatan P, Lai H. 1971. A study of intermediates adsorbed on platinized platinum during the anodic oxidation of formaldehyde. J Electroanal Chem 34 173-183. 

These properties make CoTAA a good catalyst for the anodic oxidation of formic acid. Economic application of this catalyst is, however, not anticipated because formic acid is not economically attractive as a fuel. It is certainly possible to prepare electrodes containing a mixture of tungsten carbide and CoTAA as catalyst, with the tungsten carbide catalyzing the first stage of the oxidation of CH2O to HCOOH, and the CoTAA the further oxidation of HCOOH to CO 2, but this possibility does not offer any more favorable prospects. Economic application of CoTAA will only come into question when cheap catalysts are available for the partial oxidization of methanol to formaldehyde or formic acid. 

Anodic oxidation of 6- and 7-pteridone, using electrolysis at a controlled potential, gave pteridine-6,7-dione in 95-100% yield.409 Under controlled-potential electrolysis conditions pteridine-6,7-dione is oxidized to the bridgehead diol, which undergoes rearrangement, further oxidation, and hydrolysis, yielding tetraketopiperazine, oxamide, urea, oxamic acid, ammonia, formaldehyde, formic acid, and C02-... 

In a process proposed in a recent application by Texaco 474), methanol is anodically oxidized to formaldehyde, which is then reduced cathodically to glycol in the same cell. 

Wiese and Weil [132], who used the same technique combined with fast solution exchange, confirmed the catalytic effect of formaldehyde on the reduction of the Cu-EDTA complex. They also observed that the anodic oxidation of formaldehyde... 

The anodic oxidation of 2,2-bis(ethylthio)propane producing acetone and an oxidation product of diethyl disulfide, claimed to be the corresponding disulfoxide, was reported many years ago [133]. A renewed interest in this reaction involving a C-S bond cleavage arose when bis(phenylthio)methane and some of its p-substituted ring derivatives were anodically oxidized in dry MeCN on Pt electrodes and afforded diaryl disulfides and formaldehyde, with the latter identified after aqueous workup [39, 134]. The same cleavage was observed when MeCN-H20 (9 1 v/v) was the solvent, but aryl benzenethiosulfonates were the main products [39] ... 

In the case of 1,3-dicarbonyl compounds, the solvent frequently interferes with the coupling reaction. So with diethyl sodio malonate in ethanol [212b], methanol [212b], dimethylacetamide [212b], or HMPTA [216], besides the dimer and the trimer, the compounds LIXa-c are obtained. They are presumably formed by oxidation of the solvent to the aldehyde and its condensation with the active methylene compound. No dimer was detected in the oxidation of sodio acetoacetate in ethanol, with the major product being LX [217]. Anodic oxidation of cyclic 1,3-diketones in aqueous methanolic sodium hydroxide does not yield the dimer but product LXI, formed by condensation of the starting compound with formaldehyde [218]. 

Steroidal methyl ethers are readily obtained from the alcohols with diazomethane and fluoroboric acid. The novel dicholesteryl acetal (132) of formaldehyde has been obtained from cholesterol, either by the anodic oxidation of a solution in aqueous acidic methanol, or by the action of sodium hydride and chloromethyl methyl ether. Dimethoxymethane undergoes partial exchange with cholesterol in acidic solution to give the methoxymethyl ether (133). ... 

The electro-oxidation characteristics of formaldehyde has been investigated by Lamy and coworkers ° and was studied due to its simple structure and the fact that it can serve as a model for understanding into the nature of oxidation of larger organic species. The group reported that the implementation of experimental methods are complicated by the fact that thef system involves an equilibrium between formaldehyde and methylene glycol, which is the main species in aqueous solutions. It was determined that the anodic oxidation of formaldehyde Is accompanied by the formation of strongly adsorbed species which have been identified as adsorbed CO by in-situ IR spectroscopy In alkaline - and acidic media. ... 

During a series of electrochemical reactions, oxidation of small organic molecules (SOMs) such as formaldehyde (HCHO) on a Pt electrode affects the potential (or current) on a Pt electrode. Namely, the surface reactions cause oscillatory pattern of the aforementioned variables. The anodic oxidation of HCHO on a Pt surface is believed to be accompanied by the appearance of intermediate species, i.e. CO and OH. Therefore the overall reaction, which involves the reaction of PtOH with the intermediate Pt-CO and the conversion of Pt-OH to Pt oxides, leading to the occurrence... 

In the 1920 s, E. MQller and his co-workers made a series of studies on the anodic oxidation of methanol, formaldehyde, and formic acid which represent the first extensive mechanistic investigation of these compounds, although the principles of electrode kinetics had not yet been formulated. Muller did not establish mechanisms for these reactions however, many of his observations have been later confirmed and his studies were among the first with a comparison of polarization curves on several noble metals including platinum, palladium, rhodium, iridium, osmium, rubidium, gold, and silver (cf. Figure 1). As was usual at that time, Muller discussed his results in terms of polarization, rather than in terms of current or reaction rate. 

No mechanism studies are available for the anodic oxidation of ketones and very few for aldehydes, the latter being carried out primarily in connection with the oxidation of alcohols and carboxylic acids. The anodic oxidation of formaldehyde and acetaldehyde will be only briefly discussed. 

The anodic oxidation of formaldehyde in acid media yields CO2 at essentially 100% current efficiency. From controlled potential oxidation experiments, it was reported that the amount of formaldehyde which is oxidized is independent of the anode potential between 0.4 and 1.0 V (N.H.E.). In basic solutions the main reaction product is formate which is only slowly oxidized in alkaline media. ... 

R.P. Buck, L.R. Griffith, Voltammetiic and chronopotentiometric study of the anodic oxidation of methanol, formaldehyde, and formic add, J. Electiochem. Soc. 109 (1962) 1005-1013. 

Protonated formaldehyde is generated in situ via anodic oxidation of methanol and furnishes the mono hydroxylated ketones 215 and 218 diastereoselectively [72]. 

The situation is different when the instantaneous efficiency of CO2 production is considered. As it is well known, formaldehyde and formic acid are intermediate products in the anodic oxidation of methanol. Since CH2O and HCOOH are found in the bulk of the solution, the instantaneous oxidation may be described by the scheme [22] ... 

The behavior of formaldehyde differs in some aspects from that of higher aldehydes. After adding formaldehyde, potentials below 0.1 V are established as for methanol. It was proposed [39] that the hydrogenation of formaldehyde proceeds in sulfuric acid solution only until methanol is formed. Chemisorbed species similar to those formed in the presence of methanol or formic acid are produced at open circuit [58] and by anodic oxidation [40] of formaldehyde. 

Determine the global anode oxidation and cathode reduction reactions for trioxane, formaldehyde, and... 

M. V. ten Kortenaar, C. Tessont, Z. I. Kolar, H. van der Weijde, Anodic oxidation of formaldehyde on gold studied by electrochemical impedance spectroscopy an equivalent circuit approach, J. Electrochem. Soc., 1999,146,6, pp. 2146-2155. 

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