Reduction aqueous solutions

Perkins MJ (1996) A radical reappraisal of Gif reactions. Chem Soc Rev 25 229-236 Phulkar S, Rao BSM, Schuchmann H-P, von Sonntag C (1990) Radiolysis of tertiary butyl hydroperoxide in aqueous solution. Reductive cleavage by the solvated electron, the hydrogen atom, and, in particular, the superoxide radical anion. Z Naturforsch 45b 1425-1432 Pimblott SM, LaVerne JA (1997) Stochastic simulation of the electron radiolysis of water and aqueous solutions. J Phys Chem A 101 5828-5838... 

Kumar and Endicott673 have examined the one-electron oxidation-reduction of [Co([14]aneN4) (H20)(02)]2+ in aqueous solution. Reduction competes successfully with dimerization in this system and even mildly reducing metal ions such as Fe2+ react via an inner-sphere process. Presumably this pathway is preferred owing to the large free-energy changes associated with formation of the p-peroxo adducts. With Fe2+ the adduct is observable as a transient CoOOFe species, which decays to Fe3+ and unspecified cobalt products. 

In alkaline aqueous solution, reduction of iodate ion by tetrahydroborate ion has been found to compete with hydrolysis, the rate law being of the form... 

Although only a few imines are stable in aqueous solution, reduction in cold 50% sulfuric acid at a lead cathode may give the amine [15,16]. In this connection it can be mentioned that 2,4-dihydroxybenzophenone oxime on reduction on the first wave in acid solution gives an imine stable enough to be isolated [17]. Schiff bases of some other benzophenone derivatives are stable in acid solution their reduction is a straightforward saturation of the azomethine group [18,19]. 

Experiments on DMFCs using PFSA membranes at higher temperature in the gas phase, which could give over 0.2 W/cm, ignited the development of DMFCs for electric vehicle (EV) and portable applications [83]. The PFSA membranes have a tendency to swell extremely when they are soaked in methanol aqueous solution. Reduction of the influence of methanol permeation and deformation or swelling of the membrane have been important issues in DMFC development, as shown in Table 2. 

Vracar LJM, Sepa DB, Damjanovic A (1986) Palladium electrode in oxygen-saturated aqueous solutions, reduction of oxygen in activation-controlled region. J Electrochem Soc 133 1835-1839... 

In addition, Xin et al. [115] prepared multiwalled carbon nanotube-supported Pt (Pt/MWCNT) nanocomposites by both the aqueous solution reduction of a Pt salt (HCHO reduction) and the reduction of a Pt ion salt in ethylene glycol solution (EG). For comparison, a Pt/XC72 nanocomposite was also prepared by the EG method. The Pt/MWCNT catalyst prepared by the EG method has a high and homogeneous dispersion of spherical Pt metal particles with a narrow particle-size distribution. 

Sodium sulphide, NajS, formed by reduction Na2S04 with CO or H2- Aqueous solutions are oxidized to sodium thiosulphate. 

Sorbitol is manufactured by the reduction of glucose in aqueous solution using hydrogen with a nickel catalyst. It is used in the manufacture of ascorbic acid (vitamin C), various surface active agents, foodstuffs, pharmaceuticals, cosmetics, dentifrices, adhesives, polyurethane foams, etc. 

Each of these elements can be extracted by reduction of the respective oxide at high temperature, using either carbon or hydrogen or by electrolysis of an aqueous solution of a salt of the required element. 

Two important redox potentials for reduction by sulphur dioxide in aqueous solution are ... 

The oxidising properties of the aqueous solutions of chloric(VII) acid change dramatically with temperature and the concentration of the acid. Cold dilute solutions have very weak oxidising properties and these solutions will react, for example, with metals, producing hydrogen without reduction of the chlorate(VII) ion occurring ... 

Pure iron is prepared by reduction of iron(II) oxide with hydrogen, or by electrolysis of an iron(II)-containing aqueous solution. It is a fairly soft metal, existing in different form according to temperature ... 

One of the main advantages of the stochastic dynamics methods is that dramatic tirn savings can he achieved, which enables much longer stimulations to he performed. Fc example, Widmalm and Pastor performed 1 ns molecular dynamics and stochastic dynamic simulations of an ethylene glycol molecule in aqueous solution of the solute and 259 vvatc jnolecules [Widmalm and Pastor 1992]. The molecular dynamics simulation require 300 hours whereas the stochastic dynamics simulation of the solute alone required ju 24 minutes. The dramatic reduction in time for the stochastic dynamics calculation is du not only to the very much smaller number of molecules present hut also to the fact the longer time steps can often he used in stochastic dynamics simulations. 

Recent investigation of the effect of substituents in the para position of the phenylalanine ligand on the stability of the ternary complexes has revealed the secpience Br > OH > Q NH2 > H > F". Interestingly, analysis of CD spectra indicates a reduction of the arene-arene interaction" upon addition of 1,4-dioxane to aqueous solutions of the mixed-ligand complexes, in disagreement with previous observations by Sigel" . 

The one-electron reduction of thiazole in aqueous solution has been studied by the technique of pulse radiolysis and kinetic absorption spectrophotometry (514). The acetone ketyl radical (CH ljCOH and the solvated electron e were used as one-electron reducing agents. The reaction rate constant of with thiazole determined at pH 8.0 is fe = 2.1 X 10 mole sec in agreement with 2.5 x 10 mole sec" , the value given by the National Bureau of Standards (513). It is considerably higher than that for thiophene (6.5 x 10" mole" sec" ) (513) and pyrrole (6.0 X10 mole sec ) (513). The reaction rate constant of acetone ketyl radical with thiazolium ion determined at pH 0.8 is lc = 6.2=10 mole sec" . Relatively strong transient absorption spectra are observed from these one-electron reactions they show (nm) and e... 

The reaction is used for the chain extension of aldoses in the synthesis of new or unusual sugars In this case the starting material l arabinose is an abundant natural product and possesses the correct configurations at its three chirality centers for elaboration to the relatively rare l enantiomers of glucose and mannose After cyanohydrin formation the cyano groups are converted to aldehyde functions by hydrogenation m aqueous solution Under these conditions —C=N is reduced to —CH=NH and hydrolyzes rapidly to —CH=0 Use of a poisoned palladium on barium sulfate catalyst prevents further reduction to the alditols... 

Reference electrode based on the reduction of Hg2Cl2 to Hg in an aqueous solution saturated with KCl that is,... 

Fig. 5a. Standard (or formal) reduction potentials of actinium and the actinide ions in acidic (pH 0) and basic (pH 14) aqueous solutions (values are in volts...

Table 6 presents a summary of the oxidation—reduction characteristics of actinide ions (12—14,17,20). The disproportionation reactions of UO2, Pu , PUO2, and AmO are very compHcated and have been studied extensively. In the case of plutonium, the situation is especially complex four oxidation states of plutonium [(111), (IV), (V), and (VI) ] can exist together ia aqueous solution ia equiUbrium with each other at appreciable concentrations. 

Aminoalkoxy pentaerythritols are obtained by reduction of the cyanoethoxy species obtained from the reaction between acrylonitrile, pentaerythritol, and lithium hydroxide in aqueous solution. Hydrogen in toluene over a mthenium catalyst in the presence of ammonia is used (34). The corresponding aminophenoxyalkyl derivatives of pentaerythritol and trimethyl olpropane can also be prepared (35). 

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