Formaldehyde/formic acid and

The conventional electrochemical reduction of carbon dioxide tends to give formic acid as the major product, which can be obtained with a 90% current efficiency using, for example, indium, tin, or mercury cathodes. Being able to convert CO2 initially to formates or formaldehyde is in itself significant. In our direct oxidation liquid feed fuel cell, varied oxygenates such as formaldehyde, formic acid and methyl formate, dimethoxymethane, trimethoxymethane, trioxane, and dimethyl carbonate are all useful fuels. At the same time, they can also be readily reduced further to methyl alcohol by varied chemical or enzymatic processes. 

The main reaction product is carbon dioxide, but under certain conditions, other oxidation products are observed for short periods of time, such as formaldehyde, formic acid, and others. The oxidation of methanol to CO2 yields six electrons, so that the specific capacity of methanol is close to 0.84 Ah/g. 

Oxidation of the adsorbed species resulting from interaction with formaldehyde, formic acid, and methanol, respectively, leads to stripping peaks that are downshifted to more negative potentials. Furthermore, the adsorbate coverage is significantly lower... 

Some of these techniques are perhaps self-evident it is known, for example, that methanol can be oxidised not only to C02 but also to formaldehyde, formic acid and even (reportedly) methyl formate in strongly acidic aqueous solutions. Clearly any mechanism must account for the formation of all of these products. 

Treatment of granules with such reagents as liquid ammonia, liquid hydrocyanic acid, formaldehyde, formic acid, and alkalis causes swelling at room temperature, but little is known of the effects of such treatments. 

Traditional industrial oxidation routes of alcohols use stoichiometric amounts of heavy metals or mineral acids [51]. Glycerol is also easily converted into formaldehyde, formic acid and carbon dioxide [52]. 

Photolytic. Photolysis products include carbon monoxide, ethylene, free radicals, and a polymer (Calvert and Pitts, 1966). Anticipated products from the reaction of acrolein with ozone or OH radicals in the atmosphere are glyoxal, formaldehyde, formic acid, and carbon dioxide (Cupitt,... 

Photolytic. Irradiation of vinyl chloride in the presence of nitrogen dioxide for 160 min produced formic acid, HCl, carbon monoxide, formaldehyde, ozone, and trace amounts of formyl chloride and nitric acid. In the presence of ozone, however, vinyl chloride photooxidized to carbon monoxide, formaldehyde, formic acid, and small amounts of HCl (Gay et al, 1976). Reported photooxidation products in the troposphere include hydrogen chloride and/or formyl chloride (U.S. EPA, 1985). In the presence of moisture, formyl chloride will decompose to carbon monoxide and HCl (Morrison and Boyd, 1971). Vinyl chloride reacts rapidly with OH radicals in the atmosphere. Based on a reaction rate of 6.6 x lO" cmVmolecule-sec, the estimated half-life for this reaction at 299 K is 1.5 d (Perry et al., 1977). Vinyl chloride reacts also with ozone and NO3 in the gas-phase. Sanhueza et al. (1976) reported a rate constant of 6.5 x 10 cmVmolecule-sec for the reaction with OH radicals in air at 295 K. Atkinson et al. (1988) reported a rate constant of 4.45 X 10cmVmolecule-sec for the reaction with NO3 radicals in air at 298 K. 

We can push this to completion. In formaldehyde, H2C=0, only two bonding electrons are assigned to the carbon atom so it has been oxidized again. In formic acid, HCOOH, only one electron is assigned to the carbon atom and in carbon dioxide, CO2, none are. So the states of increasing oxidation are methane, methanol, formaldehyde, formic acid, and carbon dioxide. 

Methanol can be absorbed through the skin or from the respiratory or gastrointestinal tract and is then distributed in body water. The primary mechanism of elimination of methanol in humans is by oxidation to formaldehyde, formic acid, and C02 (Figure 23-3). 

Oxidation of cobalt(ll) to cobalt(lll) by oxygen in the presence of N-hydroxyethylethylenediamine and carbon produces large amounts of ethylenediamine. Other products are formaldehyde, formic acid, and ammonia. The sum of the moles of ethylenediamine and ammonia produced is equal to the total number of moles of cobalt(ll) oxidized. A steady-state concentration of Co(ll)-Co(lll) is established in which the ratio Co(lll)/ Co(ll) = 1.207. Thus cobalt ion behaves as a true catalyst for cleavage of the N-hydroxyethyl-ethylenediamine. The total amount of cobalt(ll) oxidized per unit time, X, was calculated from the derived equation X = 3.8 + 7.0 k2 T — 3.8e-2-2k 1, where k2 = 0.65 hr.—1 The observed rate of formation of ethylenediamine plus ammonia also follows this equation. It is proposed that the cobalt ion serves as a center where a superoxide ion [derived from oxidation of cobalt-(II) by oxygen] and the ligand are brought together for reaction. 

Products of the reaction have been identified as ethylenediamine, formaldehyde, formic acid, and ammonia. A kinetic evaluation of rate experiments indicates that for each cobalt (II) ion oxidized either one molecule of ethylenediamine or one molecule of ammonia appears. 

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-... 

Some synthetic pathways require the addition of single carbon groups. These "one-carbon units can exist in a variety of oxidation states. These include methane, methanol, formaldehyde, formic acid, and carbonic acid. It is possible to incorporate carbon units at each of these... 

Manganese(III) has been employed for the oxidation of aldoses, and a general mechanism for the oxidation has been proposed.167 The oxidation of hexoses, pentoses, hexitols, and pentitols by Mn(III), as well as by other cations, was proposed to proceed via a free-radical mechanism,168 as shown in Scheme 26. Oxidation of alditols produces the corresponding aldoses, which are further oxidized in the presence of an excess of oxidant to the lower monosaccharides and thence to formaldehyde, formic acid, and even carbon dioxide. The kinetics for the oxidation of aldoses and ketoses by Mn(III) in sulfuric acid medium have been reported.169... 

Other N-methylations of l-[cyano-(4-methoxyphenyl)-methyI]cyclohexanol using formaldehyde, formic acid, and excess water by a modified Eschweiler-Clarke reaction are described (3). 

Disposition in the Body. Readily absorbed after oral administration and distributed in the body according to the water content of the tissues it may also be absorbed by inhalation or through intact skin. It is metabolised, much more slowly than ethanol, by oxidation to formaldehyde, formic acid, and possibly other products. Oxidation to formaldehyde is probably accomplished by alcohol dehydrogenase since the metabolism is inhibited by ethanol. Maximum concentrations of formic acid in the blood... 

This apparatus is based on the principle of the detection by flame ionisation. It is especially dedicated to the study of gaseous organic compounds (except formaldehyde, formic acid and carbon suliur). It allows the measurement of the VOC molar ratio in the helium flow (y). The gas analyser is able to perform VOC molar ratio measurements up to 10000 ppm THC. The measuring range may be selected (minimum end of scale value 4 ppm THC). Accuracy and repeatability on each range are better than 1% FSD. 

This compound oxidizes in a flow system at temperatures as low as 120 °C and possesses a region of negative temperature coefficient between about 330 and 370 °C. Products include acetaldehyde, formaldehyde, formic acid and peroxides. Below 250 °C, acetaldehyde is the sole non-peroxidic organic product [95]. This is formed by a 1 5 intramolecular H-transfer followed by j3-scission. 

Using the photoionization technique, Matthews and Warneck (j ) measured the appearance potentials of HCO (g) from formaldehyde, formic acid and acetaldehyde as 11.95, 12.79 and 11.79 eV, respectively, whose average yields AjH (CHC0, g, 0 K) - 197.7 1.5 kcal mol", based on the following A H (0 K) data (in units of kcal mol" ) 51.63 for H(g), 9.35 for OH(g), 35.62 for CHg(g), -26.78 for HgCOCg) (2), -88.74 for HCOOH(g) (3) and -37.14 for CHgCHO (4). The appearance potentials obtained from photoionization are several tenths to 1 eV lower than the recent electron impact data (5, 6, 7, 8, 9). The appearance potentials determined by the electron impact method tend to be high because the fundamental nature of the process does not lead to a sharp o pet in contrast to the step-function behavior of photoionization onset. 

The reaction was performed under the fixed reaction conditions described in the Experimental section, while changing the contact time from 0.3 to 5.0 s. The main products detected were glyoxylic acid, formaldehyde, formic acid, and carbon oxides. The yields of these products are plotted as a function of the conversion of glycolic acid in Figure 1. The slope of lines from the origin indicate the selectivities to each product. 

Dialysis removes the formaldehyde, formic acid, and methanol that build up in the bloodstream. The bicarbonate neutralizes the acid produced and helps offset the resultant acidosis. The ethanol competitively binds with the alcohol dehydrogenase. This slows the dehydrogenation of the methanol and allows time for the kidneys to excrete it. 

In trying to confirm their theory in regard to the intermediate formation of oxygenated products during combustion, Bone 9 and his co-workers carried out extensive researches and from their work has come the present hydroxylation theory. According to Bone the oxidation of methane takes place in steps, methanol, formaldehyde, formic acid, and carbonic acid being formed in the order named. These various steps are indicated below. The double arrows point out the mam course of reaction, while the single arrows show how the intermediate compounds may decompose. 

In 1906 Harries88 was finally able to obtain small quantities of formaldehyde as the result of a very painstaking investigation in which he used dry ozonized oxygen at temperatures of 15° to 18° C. The product, however, was not pure but consisted of a mixture of formaldehyde, formic acid, and hydrogen peroxide. 

Needless to say, we have only touched on a few of the many analytical procedures involving air samples. Other analyses performed include the determination of acetylene, total aldehydes, ammonia, formaldehyde, formic acid, and total organic acids. Various aerosol fractions in the air are commonly analyzed. 

Methanol, which nowadays is prepared by hydrogenation of carbon monoxide, contains traces of formaldehyde, formic acid, and water as impurities. The water content can be reduced to below 1% by fractional distillation treatment with magnesium turnings has become established for complete removal of water and formic acid ... 

Out of the many chlorinated derivatives, vinyl chloride has been a focus of interest since its carcinogenic effects were discovered. Approximately 6% of its world production is assumed to escape into the atmosphere. Vinyl chloride is used for the production of different plastics and methylchloro-form, and it is added to mixtures for the production of special packing materials. Until recently it has been used as a medium in aerosol sprays. The imission concentrations in the vicinity of production sources (0 to 8 km) are generally below 2.6 ng m. In the literature, there are only few data about its atmospheric reactions. It is very probable that it participates in photooxidation reactions in the presence of nitrogen oxides. Carbon monoxide formaldehyde, formic acid and HCl are products of its photooxidation. 

The very considerable research work of Bone and his associates led to his support of the hydroxylation mechanism for homogeneous oxidation of hydrocarbons with molecular oxygen. According to this mechanism, reaction between methane and oxygen takes place in steps methanol, formaldehyde, formic acid, and carbon dioxide, in the order named. That methanol has not been found among the products of methane oxidation under conditions where its presence could logically be expected does not necessarily preclude the possibility that it was the initial product. This is due to the thermal instability of methanol under the conditions and its tendency to decompose to hydrogen, carbon monoxide, and formaldehyde. 

This algorithm is executed simultaneously for each reactant, including Ag(II), ethylene glycol, formaldehyde, formic acid, and carbon dioxide. 

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