Alcohol oxygen uptake

The first step in the complete biodegradation of primary alcohol sulfates seems to be the hydrolysis to yield alcohol. Sulfatases are able to hydrolyze primary alcohol sulfates. Different authors have isolated and used several sulfia-tase enzymes belonging to Pseudomonas species. The alcohol obtained as a result of the hydrolysis, provided that dehydrogenases have been removed to avoid the oxidation of the alcohol, was identified by chromatography and other methods [388-394]. The absence of oxygen uptake in the splitting of different primary alcohol sulfates also confirms the hydrolysis instead of oxidation [395, 396]. The hydrolysis may acidify the medium and stop the bacterial growth in the absence of pH control [397-399]. 

Apparent activation energies for the catalytic reactions were as expected about 80 kJ/mol for the formation of formaldehyde and 60 kJ/mol for the formation of acetaldehyde from the respective alcohols (Figure 3). The turnover rates of the samples were calculated either on the basis of the number of vanadiums (all of which could be assumed to be accessible) or by assuming that oxygen uptake counted the catalytic sites ... 

The secondary alcohols are oxidized to ketones. In such oxidations, although air facilitates the process, but there is no oxygen uptake and since (CH3)2S has been isolated from the reaction products, it shows that DMSO is the oxidant. The mechanism in these oxidations is proabably as follows ... 

Oxygen uptake during substrate oxidation was measured with a Clark oxygen electrode (Rank Brothers, Cambridge, U.K.) at room temperature with 1 mM substrate in 0.25 mM sodium tartrate buffer, pH 3.0 (3 mL). Rates are expressed relative to veratryl alcohol oxidation. 

The rates of 2-propanol oxidation were measured for reactions run over an 8% Pt/Si02 catalyst in water at 20°C. The initial rates of oxygen uptake (about 10% conversion) were determined at three fixed partial pressures of oxygen over a range of alcohol concentrations. The resulting data are listed in Table 7.1. 

Secondary alcohols give the respective ketones as products, regardless of the reaction conditions. Primary alcohols, however, can produce either aldehydes or carboxylic acids. Commonly, these oxidations are run in basic aqueous media. Under these conditions, the aldehydes that are formed initially react with the water to form a hydrate and this is oxidized further to the acid. Aldehydes, particularly aryl aldehydes, are the primary product only when the reaction is run in a neutral, preferably non-aqueous, medium such as a hydrocarbon solvent and usually with controlled oxygen uptake. 3,62... 

In view of the susceptibility of benzaldehyde to autoxidation, it is remarkable that in the presence of DMSO the reaction stops at the aldehyde stage. In fact when a solution of benzaldehyde in DMSO was refluxed for 24 hrs. with air passing through the solution, only 1.6% of benzoic acid was isolated and 87% of benzaldehyde was recovered. Although air facilitates the oxidation, there is no oxygen uptake and isolation of dimethyl sulflde as such or as the mercuric chloride derivative (m.p. 150°) shows that DMSO is the oxidant. Several substituted benzyl alcohols were oxidized by the same method to the aromatic aldehydes. The one allylic alcohol... 

The Co(salophen)/zeolite catalyst was used in the oxidation of benzyl alcohol. The activities of the zeolite-encapsulated catalysts were compared to the free complexes in the oxidation reaction. For this comparison, we were using the same amount of Co(salophen) in both cases, and the oxygen uptake curves are given in Figure 1. 

Figure 1. Oxygen uptake curves for the oxidation of benzyl alcohol over Co(Sp) and Co(Sp)/Z catalysts...

Contact of one cm of a 0.025 molar solution of dialkyl phosphite in tetradecane at 403 K (130 C) with one gram of iron powder which had been ball milled under pentane resulted in depletion of the phosphorus in solution, as shown in Fig. 11-9. Reaction as well as adsorption took place, for soluble iron was found in the solutions of di(2-ethyIhexy1), dilauryl and distearyl phosphites. Chromatography of the solutions after contact revealed large quantities of alcohol dibutyl phosphite and di(2-ethylhexyl) phosphite yielded 92-97% of the theoretical amount of alcohol after 24 hours. Hydrolysis of the phosphite esters was ascribed to water adsorbed on the walls of the reaction tube and on the iron powder. Forbes and Battersby [46] postulated that hydrolysis is an important aspect of the mechanism of the additive action of phosphite esters. Oxidation to phosphate by the oxygen of the ambient air is deemed minor maximum augmentation of the oxygen uptake by a 6.5% solution of dibutyl phosphite over that of the tetradecane carrier fluid in the presence of iron was 20%. The easy hydrolysis of phosphites is well known. Partial... 

In 1936 Keilin and Hartree (75) showed that addition of ethyl alcohol to certain enzymatic oxidation systems such as uricase with uric acid and amino acid oxidase with amino acids doubles the oxygen uptake. 

An indication for the degradation pathway used by the seven microorganisms unable to grow on perillyl alcohol was obtained by performing oxygen uptake experiments (Table 1). 

Strain DCLi4 was chosen for further experiments as it had the lowest oxygen uptake with perillyl alcohol, and high oxygen uptake rates with carveol and carvone. 

The oxygen consumption and yields of oxidation products are frequently used indices of radiation-induced degradation by oxidation. The oxidation process depends on the irradiation conditions, i.e. the atmosphere, pressure, dose rate, temperature and sample dimensions. The oxygen uptake may be determined by measurements of the oxygen content before and after irradiation, where the oxygen products include carbon dioxide, carbon monoxide, water, hydroperoxide, alcohols, ketones and carboxylic acids [3]. 

Both ethanol and lactic acid, products of anaerobic respiration, accumulate in the pea seed prior to the penetration of the radicle through the enclosing testa [38, 39]. Following radicle emergence their levels diminish as they are metabolized under the conditions of increasing aerobiosis. This event is accompanied by increased oxygen uptake, CO2 output and a fall in R.Q. Alcohol... 

Fig. 5.2. Alcohol dehydrogenase activity ( ) in, and oxygen uptake by cotyledons of dark-germinated intact pea seeds cv. Rondo. Germination time as Figure 5.1 A. After Kolloffel, 1968 [68]...

The effective oxidizability parameter for oxygen uptake in the oxidation of 2-hydroxycyclo hexanone (RCH(0H)C(0)R) initiated by azobisisobutyronitrile in C6H5CI has been determined. The rate constants for chain propagation and termination and the equilibrium constant for addition of the hydroxyperoxyl radical to the keto alcohol are also reported. The ratio of the rate constants of quadratic-law peroxyl radical recombination reactions without and with chain termination increases with increasing [RCH(0H)C(0)R], passes through a maximum ([substrate] = 0.8 mol dm ) and then falls off this has been attributed to the variation of the proportions of the hydroper-oxyl and l-hydroxy-2-oxocyclohexylperoxyl or 1,2-dihydroxy-1-cyclo-hexylperoxyl radicals in the reaction medium." i... 

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