Oxidation of n-decanal

The oxidation of n-decanal was examined in great detail by Cooper and Melville in 1951 [23]. Kinetic investigations were made under the conditions at 350—700 torr and 0—30° C using -decane as solvent. The results lead to the following conlusions with regard to the rate of thermal oxidation, yth, and the rate of purely photochemical oxidation, Vph. 

If it is assumed that thermal initiation is brought about by the reaction RCHO + 02 -+ radicals 

if the terms relating to initiation are disregarded, both rate expressions are the same. 

Assuming stationary concentrations of active species and that the chains are long, the expression obtained for the rate of oxygen absorption (when 

By experimentally determining the rate of photochemical initiation, from an examination of the rate of inhibited n-decanal oxidation, and by determining the concentration of peroxidic species (obtained by the rotating sector method), it is possible to calculate the propagation (k3) and rupture (ft6) coefficients which, at 5°C, are 

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According to Melville and his co-workers, the thermal oxidation of n-decanal and benzaldehyde in liquid phase at around 10°C. must also involve a chain mechanism which would differ from that of photooxidation only in respect to the process of initiation in the case of the thermal reaction, the initiation process would be ... 

It was found for the oxidation of heptane [140] that up to 90% of C02 is formed in parallel with the acids and only 10% by decarboxylation of acids. Oxy- and ketoacids (up to 18% of all acids) were found to be produced in parallel with fatty acids in the oxidation of n-decane [141]. All the above facts are inconsistent with the assumption that the a-C—C bond only is broken on oxidation of ketones. Undoubtedly, some ketones are oxidized with scission of two C—C bonds. This conclusion is confirmed by the prevailing amount of lower fatty acids and parallel formation of C02 and acids in the oxidation of paraffins. Obviously, not only the a-CH2 group but also other CH2 groups are attacked in the ketone molecule. This results in the formation of bifunctional compounds with subsequent oxidation to acids, oxyacids, and ketoacids. The competing attack by peroxy radicals at the a-CH2 and other CH2 groups will be discussed later. 

This beneficial effect was attributed to rate enhancements of reduction processes. With benzoic acid, total degradation of the ring to CO2 occurred and the detection of salycilic acid suggested the intervention of 0H° radicals (56). These radicals were also proposed to explain the oxidation of n-Cx alkanes (x = 6,7,9,10) and of cyclohexane in 1 1 vol. water ydrocarbon two-phase mixtures over 10 wt °l Pt/Ti02 Traces of alcohols (and of 2-, 4-, 5-decanone with decane) were detected. No transformation occurred without O2 and in the absence of H2O the rate was substantially decreased. The role of Pt was attributed to a greater ease of oxygen reduction however the oxidation rate was only decreased by a factor of about 1.5 without Pt (59). 

Lastly, let us point out that in 1953 the photochemical oxidations of mixtures of benzaldehyde and of n-decanal were studied by Ingles and Melville. The kinetic characteristics of the reactions indicate that in mixtures these aldehydes do not undergo oxidation independently of one another the two molecules are involved in a single kinetic chain, exactly as in a copolymerization reaction. 

The introduction of hydrocarbons in the feed has a larger effect on NO oxidation and reduction. In the presence of n-decane (Fig. 4), NO is not oxidised before 230°C while in the presence of ethylene (Fig. 4), NO2 is detected only above 290°C. As in the presence of CO, NO oxidation is delayed until most of the reductant is eliminated. But hydrocarbons are oxidised at higher temperatures than CO and the nature of the hydrocarbon strongly affects its own oxidation n-decane is oxidised around 220°C while ethylene is oxidised around 280°C. 

As in the absence of reductant, NO2 concentration goes through a maximum when temperature increases, but this maximum is clearly below that observed without reductant. This can be explained if we consider that the thermodynamic equilibrium for NO oxidation should more appropriately be expressed with the reactor outlet temperature than to the reactor inlet temperature under adiabatic conditions the temperature increase is about 120 C for the combustion of 6000 ppmC hydrocarbon. This temperature shift is well suited to explain the NO oxidation curve in the presence of ethylene. It is less adapted in the presence of n-decane probably because decane oxidation is diffusion limited and reaches total conversion only at high temperature NO oxidation is not at equilibrium. 

GLAUDE P.A., WARTH V., FOURNET R., BATTIN-LECLERC F., SCACCHI G., COME G.M., Modelling of the Oxidation of n-Octane and n-Decane Using an Automatic Generation of Mechanisms, Int. J. Chem. Kin., 20, 949 (1998). 

Tabulation was successfully used for the description of the oxidation of n-heptane, iso-octane, -decane and -dodecane. The agreement was good compared with the results of detailed chemical calculations for all alkanes when only 20 progress variable light species were used (Kourdis and Bellan 2014). Tabulation was applied by Xuan and Blanquart (2014) for the calculation of the concentrations of polycyclic aromatic hydrocarbons (PAHs) in non-premixed flames. 

Equation (10) indeed predicts that the membrane conductance goes through a maximum at pKai = pH and is proportional to the square of the total anion concentration, [W ] total. The results of Wardak are consistent with the analysis of Finkelstein s. in this connection, Dilger et al. suggested that because of the ability of weak acids to transport protons across BLM and to uncouple oxidative phosphorylation in mitochondria, some fraction of the lipid bilayer component of the cristae membrane must have a dielectric constant greater than 2.2. This conclusion is based on the experiments of Dilger et al. , who used chlorodecane as the BLM (t = 4.5) instead of n-decane (t 2). In the presence of thiocyanate, the conductance of chlorodecane-BLM is one thousand times larger than n-decane-BLM. The specific capacitances, which are proportional to z/tm, are 0.73 and o.39 pF/cm for chlorodecane BLM and n-decane-BLM, respect-... 

Reasonable NO conversion can be achieved using n-decane as reductant. In the absence of sulfur dioxide, the catalytic activity is roughly related to the r ucibility of the Cu phase of Cu ions in zeolites the reaction temperature needed to reach 20% NO conversion parallels that of the TPR peak (Table 7). This relation also practically holds for Cu on simple oxides, therefore a redox mechanism in which reduction of Cu + cations is the slow step could account for the results. 

A few other oxidations involve no C=C bond cleavage. Cti-9-octadecene gave 9.10-diketo-octadecane with RuO /aq. Na(C10)/( Bu N)Br/CHjCl2 [324], while cyclo-octene was oxidised by RnCyaq. Na(10 )/DCE to 8-oxo-octanal [325]. Oxidation of A -, and A - steroids using RuO /aq. Na(10 )/acetone gave cis-diols, diones and acids [303] while RuO /aq. Na(10 )/CHjCyCH3CN oxidised 2,3-dichlorodecene to decane-2,3-dione [326]. 

W3 (0) j ] were used, as ("Bu N) salts, as complex/aq. Na(lO )7DCE/60°C to effect oxidative cleavage of styrene to benzaldehyde and benzoic acid. Kinetic studies and activation parameters were determined [707]. The system a-( Hx N)j[Ru Si(H30)W,(0)3, ] /TBHP/C H oxidised cyclohexane, n-heptane, n-decane and ethylbenzene to alcohols and ketones [708]. 

Similar dependences were obtained for the oxidation of methyl ethyl ketone in a solution of p-dichlorobenzene, n-decane, and CC14 (Figures 3 and 4) and in acetic acid solutions. 

Similar experiments were carried out in which drops that were mixtures of /i-decane and various alcohols were injected into dilute solutions of a zwitterionic (amine oxide) surfactant. Here, too, the lamellar phase was the first intermediate phase observed when the system was initially above the PIT. However, with alcohols of intermediate chain length such as /i-heptanol, it formed more rapidly than with oleyl alcohol, and the many, small myelinic figures that developed broke up quickly into tiny droplets in a process resembling an explosion.The high speed of the inversion to hydrophilic conditions was caused by diffusion of n-heptanol into the aqueous phase, which is faster than diffusion of surfactant into the drop. The alcohol also made the lamellar phase more fluid and thereby promoted the rapid breakup of myelinic figures into droplets. Further loss of alcohol caused both the lamellar phase and the remaining microemulsion to become supersaturated in oil, which produced spontaneous emulsification of oil. 

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