SUBJECTS compounds 838 formic acid

A relatively unique type of reactive metabolite is carbene, i.e., a divalent carbon, which is a proposed intermediate in the oxidation of methylene dioxy-containing compounds. A methylenedioxy group in aromatic compounds is subject to O-dealkylation, e.g., 3,4-methylenedioxyamphetamine, as shown in Figure 8.20. The process generates formic acid and the catechol metabolite as final products. However, in the course of the reaction, a... 

Many groundwaters are contaminated with the cleaning solvents trichloroethylene (TCE) and perchloroethylene (PCE). They are two of the most common organochlorine compounds found in Superfund sites. Radiation-induced decomposition of TCE in aqueous solutions has been the subject of several recent studies [15-20]. In most of the referenced studies, the complete destruction of TCE was observed. Dechlorination by a combination of oxidative and reductive radiolysis was stoichiometric. Gehringer et al. [15] and Proksch et al. [18] have characterized the kinetics and mechanism of OH radical attack on TCE and PCE in y-ray-irradiated aqueous solution. Trichloroethylene was readily decomposed in exponential fashion, with a reported G value of 0.54 pmol J-1. A 10 ppm (76 pM) solution was decontaminated with an absorbed dose of less than 600 Gy. For each OH captured, one C02 molecule, one formic acid molecule and three Cl- ions were generated. These products were created by a series of reactions initiated by OH addition to the unsaturated TCE carbon, which is shown in Eq. (45) ... 

Other products observed in this first study with the long-path cell were aldehyde, alkyl nitrate, formic acid, carbon monoxide, carbon dioxide, and water. Several prominent absorptions vhich apparently all belong to one compound could not be identified. This interesting product, referred to as compound X, has been subjected to considerable study in an attempt to determine its structure and physical properties. Aside from ozone, it is probably the most important product of these reactions (37). 

At this point, to complete the subject of the radical oxidation of substituted carboxaldehydes, mention should be made of the findings concerning glyceric aldehyde [43], In the aqueous phase, the oxidation of this compound is a chain reaction. The accumulation of intermediate products such as glyceride and glycolic acids at the same time as acetic and formic acids and C02 indicates that this aldehyde has two reactive oxidation sites, i.e. the carbonyl group and the carbon a to this group. 

Nitrile reduction with BH3 proceeded with cycUzation to give 8. This underwent catalytic hydrogenation in the presence of formic acid to afford the (-)-deacetylanisomycin (2). Compound 2 was subjected to a five-step sequence to produce 1 [2,26,50-52]. Thus, N-carbamate protection of 2 afforded carbamate 9, which was selectively sililated to give 10. This was acetylated to produce 11 that on treatment with TBAF followed by catalytic hydrogenation furnished (-)-anisomycin (1). 

The electrooxidation of simple one-carbon molecules (Ci molecules), such as methanol, formaldehyde, and formic acid, became the subject of considerable and continuous interest. This is quite reasonable since these compounds, particularly methanol, are potential fuels for fuel cells. The complete oxidation of the... 

Levuhnic acid is one of the products of selective dehydration of cellulosic biomass feedstocks. Levuhnic acid is produced when six-member ring carbohydrates derived from ceUulose are subjected to acid-catalyzed dehydration conditions (Fig. 9.6) [4, 43]. The other main product of this reaction is formic acid. Although levulinic acid has some potential use as a solvent or in the production of industrial and pharmaceutical chemicals, its current market is minimal [4]. Therefore, the conversion of levulinic acid to a directly usable biofuel has become an important area of interest. In particular, esterification, oxidation, hydrogenation, reductive amination, condensation, and enzymatic conversion have been tested as potential methods to produce useful compounds from levulinic acid [4,44,45]. 

The results are given in Table I. Although the absolute G values may be subject to systematic errors of up to 50%, the relative values in the different systems are significant to 10% except in those cases where the yields are less than 0.05 where the limits of error may be 20%. Nevertheless, these results show that the trapping ability of the solutes, if such is the case, is vastly different for the different compounds, being, in fact, absent in the case of chloride, nitrate, nitric, formic, and acetic acids. However, these differences in the trapping abilities of different solutes are not explicable on the basis of the trap theory. 

A DESI source is similar to an ESI source except that there is no secondary flow of heated nitrogen to dry the nebulized droplets (Figure 2.17), so a spray is produced. A mixture of methanol and water is subjected to a potential of 3-5 kV and then nebulized with nitrogen supplied at 5 x 10 Torr ( 7 bar). The spray mixture may be modified with acid (acetic or formic) or ammonia to enhance ion formation. The stream of charged droplets is then directed at the surface of solid samples, a few millimeters away, from which the analyte(s) is ejected. The desorbed compounds leave... 

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