Formic acid, from oxidation

A different technique utilizes the Warburg respirometer to measure the carbon dioxide liberated by formic acid from a dilute, sodium bicarbonate solution.84 286 Successful application of the method necessitates a pH value of 5.7, which is somewhat high for optimal periodate oxidations, but good results were reported in experiments on a number of materials, including polysaccharides. The procedure is applicable to very small amounts and does not require prior destruction of periodate. 

On periodate oxidation, open-chain (1— 4)-linked polysaccharides yield one molecule of formic acid from the nonreducing end and two molecules of formic acid, as well as one molecule of formaldehyde, from the reducing end. 

From the very good activity of thermally or electrochemically activated CoTAA for the reaction of CO one might deduce that the oxidation of formic or oxalic acid proceeds, not directly, but by way of a preliminary decarbonylization reaction. However, there is no evolution of gas from CoTAA in a solution of formic acid in dilute sulfuric acid, even at 70 °C. Such a reaction would have to occur on chemical decomposition of formic acid, with evolution of CO and H2O, or CO2 and H2. It may thus be assumed that formic acid is oxidized directly. 

Atmospheric oxidation of methane, 81 dimethyl peroxide from, 81 formaldehyde from, 81 formic acid from, 81... 

VC Mason, M Rudemo, S Bech-Andersen. Hydrolysate preparation for amino acid determinations in feed constituents. 6. The influence of phenol and formic acid on the recovery of amino acids from oxidized feed proteins. Z Tierphysiol Tierernaehr Futtermittelkd 43 35-48, 1980. 

The aqueous oxidation of D-[l-14C]glucose and D-[6-14C]glucose at 100 °C afforded formic, acetic, and glycolic acids, and carbon dioxide. The last is mainly produced from C-2 to C-5, the formic acid from C-l, and the acetic acid from C-6.96 Addition of aluminum(III) chloride greatly increased the yield of carbon dioxide. Oxidation of D-glucose and D-fructose, studied with lsO-enriched oxygen, showed that they decompose via the C-l and C-2 hydroperoxides to give D-erythronic acid as the main product.76... 

In these catalyzed oxidations, formic acid production did not parallel the uptake of lead tetraacetate49 and, particularly with the D-mannopyrano-side and D-galactopyranoside, fell far short of the theoretical value of one mole per mole (see Fig. 2). Methyl a-D-mannoside yielded only one third of a mole of free acid per mole, a result which agreed well with the earlier formulation97 of the ester (XLVII) as the reaction product to be expected. The almost equally low yield of formic acid from methyl a-D-galactopyrano-... 

Formic acid seems to arise from oxidation of formaldehyde. On the other hand, Berger et a/.154 169 have suggested the formation of formic acid from a glucose residue cleaved with participation of the hydroxyl group of the 6-CH2OH moiety. 

In fact, formic acid oxidation is a transparent example in which the features that lead to sustained oscillations in oxidation reactions of organic molecules and are described above in general terms can be deduced from the reaction mechanism in a straightforward manner. It is widely accepted that formic acid is oxidized in two parallel pathways,... 

Ahmad, T., Kenne, L., Olsson, K., and Theander, O., The formation of 2-furaldehyde and formic-acid from pentoses in slightly acidic deuterium-oxide studied by H-l-Nmr spectroscopy. Carbohydrate Res 1995, 276 (2), 309-320. 

In this last reaction, it will be observed, twice as much carbon di-oxide is used as in the preceding reaction in the formation of formic acid from carbon di-oxide. Now, carbon mon-oxide and carbon are the reduction products of carbon di-oxide, and in the light of all of the reactions which we have just considered, we may represent the theoretical stages in the reduction of carbon di-oxide as follows. 

In spite of the elimination of formic acid in a couple of steps changing the oxidation number of the rhodium metal center from -nl to -i-3 and vice versa, the reaction could take place by an alternative mechanistic pathway via cr-meta-thesis between the coordinated formate unit and the nonclassical bound hydrogen molecule [48, 49]. Initial rate measurements of a complex of the type 13 show that kinetic data are consistent with a mechanism involving a rate-limiting product formation by liberation of formic acid from an intermediate that is formed via two reversible reactions of the actual catalytically active species, first with CO2 and then with H2. The calculations provide a theoretical analysis of the full catalytic cycle of CO2 hydrogenation. From these results s-bond metathesis seems to be an alternative low-energy pathway to a classical oxidative addition/reductive elimination sequence for the reaction of the formate intermediate with dihydrogen [48 a]. 

Whereas acetic acid was formed in good yield from ethane, the analogous formation of formic acid from methane proceeded only in low yield because of the general instability of the latter acid under the reaction conditions. Since formic acid is a much less desirable product from methane than is methanol, the possibility of halting the oxidation of methane at the methanol stage was examined. 

Formic acid can be readily absorbed from the digestive tract and the respiratory system. Systemic absorption produces acidosis, neuropathy, and visual and mental disturbances. Acidosis can also be produced when formic acid is produced by liver aldehyde dehydrogenase from formaldehyde. Formaldehyde in turn can also be produced metabolically by alcohol dehydrogenase from methanol. Formic acid is oxidized to carbon dioxide by the folate-dependent pathway. Some formic acid is excreted unchanged in the urine. 

The second example is again taken from formic acid oxidation. In Ref. 88 two sequences of mixed-mode oscillations are described which were found when formic acid was oxidized at an elevated temperature (50 °C) at a rotating platinum electrode. The interesting aspect here is that the large amplitudes in the first sequence are as large as the small amplitudes in the second sequence. Hence, the period-1 state that separates the two sequences corresponds to the 1 state of the first sequence and the 0 state of the second one. 

To date, few reports on synthetic enzymatic oxidations of aldehydes have been published. Preparative applications reported include bioconversions of natural products such as retinal (Fig. 16.4-1 A) and various aliphatic and unsaturated aldehydes (Fig. 16.4-1 B). A broad range of aromatic acids can be obtained from their corresponding aldehydes (Fig. 16.4-1 C). Another reported reaction type is the production of olefins from aldehydes by oxidative removal of formic acid from the substrate (Fig. 16.4-1 D). 

Sodium periodate oxidation converts 48 into the corresponding aldehyde 38 and releases one mole of formaldehyde (from C-6) and one mole of formic acid (from C-5), both of which can be estimated independently. Chromium trioxide oxidation of 38 gives the corresponding acid which decarboxylates readily to the 3-unsubstituted compound 11 and... 

Bevington and coworkers have suggested a scheme for determining the distribution of radioactive carbon in labeled n-glucose, using the degradation of D-arabino-hexose phenylosotriazole. The scheme is based on the periodate oxidation of n-ambmo-hexose phenylosotriazole and d-arabino-hexose phenylosotriazole 6-benzoate. The former gives formaldehyde from C-6, formic acid from C-4 and C-5, and 4-formyl-2-phenyl-1,2,3-triazole from C-1, C-2, and C-3. This latter aldehyde can be further... 

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