Oxygen early investigations

In a number of model studies it has been demonstrated that synthetic porphyrin complexes are able to be oxidized to oxo-metalloporphyrin complexes which will, in turn, oxidize organic substrates of the type mentioned previously. Thus, in an early investigation it was shown that a synthetic Fe(m) porphyrin will catalyze oxygenation of hydrocarbons using iodosylbenzene as the reduced-oxygen source (Groves, Nemo Myers, 1979). Following this report, a number of related cytochrome... 

Many early investigators interested in determining the rate of decomposition of ozone performed their experiments in mixtures of ozone and oxygen. Their observations led them to write the following rate expression ... 

Before mercury-photosensitized decomposition of nitrous oxide could be used as a technique for generation of oxygen atoms, it was necessary to establish unambiguously the primary step in this reaction. Early investigation (70) could not distinguish with certainty between the two possible primary steps... 

Carbon-containing deposits may accumulate on surfaces during reactions with hydrocarbons. Details of the formation and nature of such species have been described by Stair (2007). Raman spectroscopy is a tool that is well suited to the investigation of carbonaceous deposits. An early investigation of such carbon-containing deposits was reported by Brown et al. (Brown et al., 1977) in 1977. If sufficient oxygen is present in a hydrocarbon environment, carbon deposition will be minimized or will not occur, and the catalysts may remain fully oxidized. 

The fluorite oxides are the classical oxygen ion conducting oxide materials the study of these materials as electrolytes derives from the early investigations of Walther Nemst 1900. The fluorite structure illustrated in Figure 13 is best described for the purposes of the present discussion as a primitive cubic array of anions (O ) with half the cube centers occupied by cations the latter form a face-centered-cubic (fee) arrangement of the cation sublattice. The unoccupied cube centers play a central role in the defect physics and ionic conductivity of fluorites, because they... 

However, early investigations into the electrical properties of solutions were somewhat frustrating as, initially, direct current (DC) measurements were made which resulted in the hydrolysis of the solvent and the evolution of oxygen at the anode and hydrogen at the cathode. The presence of bubbles of gas changed the nature of the electrode surface and hence the electrode resistance and confused the results. 

Oxidation with aqueous permanganate-methylcyclohexane. In an early investigation aimed at elucidating the structure of ergosterol, Reindel and co-workers oxidized ergosterol by an unusual procedure and obtained an oxygenated product which was identified a quarter of a century later in an investigation by M. Fieser, A. Quilico, ct The product proved to be a mixture of about 7 parts of an Oa-compound and 3 parts of an Oj-compound, and the main product was characterized as the triply unsaturated triol (2). It probably arises by c/s-hydroxylation of the 5,6-double... 

The early investigators, by repeated fractional distillation, were able to determine that crude petroleum consisted principally of hydrocarbons. Ultimate analyses had shown that relatively small proportions of sulfur, nitrogen, and oxygen were usually present, probably in the form of derivatives. They were able to identify a number of hydrocarbon types such as paraffins, cycloparaffins, and aromatics, and even to isolate some members of these series in a qualitative way. The state of the art was very well summed up by Hoefer (1888) (65) when he wrote in his book Das Erdol as follows It should be pointed out that up to the present no complete quantitative analysis has been carried out on any crude petroleum, that we must be content rather to discover which are the principal types of hydrocarbons present, which predominate and, qualitatively, to identify the individual members of such series. ... 

In the early years of carbohydrate chemistry, many chemists studied the effects of alkaline solutions on carbohydrates. Most investigations were made in the presence of oxygen or some other oxidant, and many different mechanisms for the formation of the observed products were proposed. Early investigations are summarized in a review by Evans. ... 

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