Kinetic studies of reduction

Furthermore, superhydride is used as an alternative to LAH in the reduction of carbohydrate epoxides (equation 18), In this example, the C—O bond away from the hydroxy group is selectively cleaved, but a tosyloxy group is also reduced in epoxides having a hydroxy group protected with tosyl. A kinetic study of reductions with superhydride has been reported. ... 

Arciero DM, Balny C, Hooper AB (1991) Spectroscopic and rapid kinetic studies of reduction of cytochrome c-554 by hydroxylamine oxidoreductase from Nitrosomonas europaea. Biochemistry 30 11466-11472... 

Komatsu T, Nunokawa M, Moon IS et al (1994) Kinetic Studies of Reduction of Nitric Oxide with Ammonia on Cu -Exchanged Zeolites. Journal of Catalysis 148 427-437... 

Mochida, I., Kawano, S., Hironaka, M., Kawabuchi, Y., Korai, Y., Matsumura, Y. and Yoshikawa, M., Kinetic study on reduction of NO of low concentration in air with NHj at room temperature over pitch-based active carbon fibers of moderate surface area, Langmuir, 1997, 13(20), 5316 5321. 

Kutty and Murthy [1159] have made a kinetic study of the solid—solid reaction between tricalcium phosphate and urea nitrate, a process of possible technological importance. A reduction in particle size, notably of Ca3(P04)2, increased the rate of reaction in powder mixtures and also changed the kinetic characteristics (318—338 K). Reaction in relatively coarse material (between —180 and +200 mesh) obeyed the parabolic... 

The influence of electronegative additives on the CO hydrogenation reaction corresponds mainly to a reduction in the overall catalyst activity.131 This is shown for example in Fig. 2.42 which compares the steady-state methanation activities of Ni, Co, Fe and Ru catalysts relative to their fresh, unpoisoned activities as a function of gas phase H2S concentration. The distribution of the reaction products is also affected, leading to an increase in the relative amount of higher unsaturated hydrocarbons at the expense of methane formation.6 Model kinetic studies of the effect of sulfur on the methanation reaction on Ni(lOO)132,135 and Ru(OOl)133,134 at near atmospheric pressure attribute this behavior to the inhibition effect of sulfur to the dissociative adsorption rate of hydrogen but also to the drastic decrease in the... 

Alonso-Vante N, Tributsch H, Solorza-Eeria O (1995) Kinetics studies of oxygen reduction in acid medium on novel semiconducting transition metal chalcogenides. Electrochim Acta 40 567-576... 

With the (n-Bu)jSnH reduction of PVC successfully simulated via the kinetic studies of DCP and TCH reduction, it remains to explain the mechanisms (14) of this reductive dechlorination. We need only consider the mechanisms of the reduction of DCP and TCH, because we have demonstrated that the kinetics of their reduction are the same as those observed for PVC when also reduced by (n-Bu)3SnH. 

While ether is the common solvent for LiAlH4, in which it is soluble, hydroxylic solvents like water, methanol and ethanol are preferred for NaBH4, It is more soluble in methanol than in ethanol, but since it reacts with the former at an appreciable rate than the latter, hence ethanol is the preferred solvent. Isopropanol, in which NaBH4 is stable, is used for kinetic studies of the reduction of aldehydes and ketones. 

Although, the first reaction step, reduction of the Fe(III) to the Fe(II) porph5rrin complex by KO2, could not be studied in detail because of interference of the formation of the Fe(III) hydroxo species, the second reaction step, binding of superoxide to the Fe(II) species and formation of the Fe(III)-peroxo complex, could be studied in detail 61). To our knowledge, for the first time superoxide concentration (Fig. 11) and temperature dependent kinetic studies of reactions with superoxide have been performed by stopped-fiow UVA is measurements, and as a result the second-order rate constant ( on = 36,500 + 500 s )... 

A detailed kinetic study of the enantioselective reduction of acetophenones, ArCOMe, to arylethanols, using a propan-2-ol-acetone couple and a chiral rhodium diamine catalyst, has been undertaken.Non-linear effects on the % ee are observed, e.g. addition of achiral ketones can both slow the reaction and raise the ee. These effects can be rationalized in terms of the difference in reactivity of diastereomeric catalytic sites. The scope for exploiting such mechanistic insights so as to maximize the enantioselectivity is discussed. 

Weber EJ, Wolfe NL. 1987. Kinetic studies of the reduction of aromatic azo compounds in anaerobic sediment/water systems. Environ Toxicol Chem 6 911-919. 

Because carbohydrates are so frequently used as substrates in kinetic studies of enzymes and metabolic pathways, we refer the reader to the following topics in Ro-byt s excellent account of chemical reactions used to modify carbohydrates formation of carbohydrate esters, pp. 77-81 sulfonic acid esters, pp. 81-83 ethers [methyl, p. 83 trityl, pp. 83-84 benzyl, pp. 84-85 trialkyl silyl, p. 85] acetals and ketals, pp. 85-92 modifications at C-1 [reduction of aldehydes and ketones, pp. 92-93 reduction of thioacetals, p. 93 oxidation, pp. 93-94 chain elongation, pp. 94-98 chain length reduction, pp. 98-99 substitution at the reducing carbon atom, pp. 99-103 formation of gycosides, pp. 103-105 formation of glycosidic linkages between monosaccharide residues, 105-108] modifications at C-2, pp. 108-113 modifications at C-3, pp. 113-120 modifications at C-4, pp. 121-124 modifications at C-5, pp. 125-128 modifications at C-6 in hexopy-ranoses, pp. 128-134. 

Actually, the kinetics study of the redox potential of transient clusters (Section 20.3.2) has shown that beyond the critical nuclearity, they receive electrons without delay from an electron donor already present. The critical nuclearity depends on the donor potential and then the autocatalytic growth does not stop until the metal ions or the electron donor are not exhausted (Fig. 8c). An extreme case of the size development occurs, despite the presence of the polymer, when the nucleation induced by radiolytic reduction is followed by a chemical reduction. The donor D does not create new nuclei but allows the supercritical clusters to develop. This process may be used to select the cluster final size by the choice of the radiolytic/chemical reduction ratio. But it also occurs spontaneously any time when even a mild reducing agent is present during the radiolytic synthesis. The specificity of this method is to combine the ion reduction successively ... 

Somewhat lower values of 1.0x10 and 1.2xlO M respectively were deduced from a kinetic study of the inhibition by green pea SOD of the reduction of Fe(III)-cytochrome c with xanthine oxidase as a superoxide generating system . 

The chromium(II) complex of 1,4,8,12-tetraazacyclopentadecane ([15]aneN4 81) has been prepared in aqueous solution and used as an intermediate in the production of chromium(III) complexes (Scheme 25), including some which contain Cr—C o bonds.297 Its powerful reducing ability and the chemical inertness of the Cr111 products (it is preferable to Cr2+aq) have been exploited298 in kinetic studies of the reduction of ferredoxins. 

Heterogeneous charge transfer kinetic study of the reduction of benzonitrile (BN) in N, JV-dimethylformamide using NPSVa... 

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