Octadecane oxidation

The rate of decarboxylation of labelled caproic acid in octadecane oxidation decreases as other acids accumulate in the hydrocarbon [207]. This is due to dimerization of the acids via hydrogen bonds, preventing... 

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]. 

To quantitatively determine the absolute amounts of certain esters present in the oxidation products, the mass spectrometer responses to these compounds were compared with the response to the internal reference, octadecane. Using authentic samples of the esters of interest, relative mass spectrometric response factors were determined. From these response factors, listed in Table I, the amounts of esters present in the oxidative degradation products were calculated using an INCOS subroutine. 

Fatty alcohohNAD oxidoreductase is a complex enzyme which consists of two separate proteins that sequentially catalyze the oxidation of fatty alcohol to fatty aldehyde and to fatty acid that is to say a fatty alcohol dehydrogenase and a fatty aldehyde dehydrogenase (FALDH) activity. Sjogren-Larsson cells were selectively deficient in the FALDH component and had normal activity of fatty alcohol dehydrogenase. Intact fibroblast oxidized octadecanol to fatty acid at <10% of the normal rate but oxidized octadecanal normally confirming that FALDH is specifically affected (Rizzo and Craft, 1991). 

One of the earliest separations in gas liquid chromatography was that of James et al. who used a mixture of hendecanol and liquid paraffin on celite using ammonia and the methyl amines as eluents in the order of their melting points. Other stationary phases used for this and for other similar separations include triethanolamine, a mixture of w-octadecane and n-hendecanol, and polyethylene oxide. Titration cell, the first detector designed specifically for gas chromatography, was used in these early studies of the separation of ammonia and ethylamines. More recently thermal conductivity cells have been used for the detection of these compounds. 

The first materials produced by this method which have obtained commercial importance are monoepoxides such as octylene oxide, dodecene oxide, and a mixture of 1,2-epoxy hexadecane and 1,2-epoxy octadecane. These epoxides are used as stabilizers for vinyl polymers and as diluents for epoxy resins. 

FIGURE 13.14 Degradation rates of " C-labeled octadecane and naphthalene in oxidized and reduced sediments from the Leesville, Louisiana oil field area. (From DeLaune et ah, 1980.)... 

FIGURE 18.24 Degraded rates of C-labeled octadecane (a) and naphthalene (b) in oxidized and rednced sediment from Barataria Bay, Louisiana. (Drawn using data from Hambrick et al., 1980.)... 

Thermogravimetrical analysis (TGA) This technique is widely employed and it measures the amount and rate of change in the weight of a material as a function of temperature under a controlled atmosphere. The measurements are used primarily to evaluate the thermal stability. The technique can characterize materials that exhibit weight loss or gain dne to decomposition, oxidation, or dehydration. As an example, Zhang et al." evaluated the step thermal degradation and the thermal reliability of a silica/n-octadecane MPCM. 

We found (Vorobjeva et al., 1979a) that propionibacteria of different species were able to oxidize a mixture of w-alkanes of the following composition (%) dodecane, 0.4 tridecane, 4.2 tetradecane, 15.7 pentadecane, 26.9 hexadecane, 26.8 heptadecane, 17.9 octadecane, 6.2 and eicosane, 0.5. They also oxidized individual w-alkanes with chain lengths from 8 to 18 carbon atoms as well as cetyl alcohol. The results of manometric investigations showed that the bacteria (except cocci) oxidized -alkanes in the mixture without a noticeable lag-period (Fig. 4.8). The absence of a latent period can be associated with a synergism of alkanes. 

The autocatalytic thermal oxidation of hydrocarbons at slightly elevated temperatures has been known for over 90 years [3], As an example of this process, the autoxidation of the saturated hydrocarbon octadecane at 105 C is shown in Figiue 6.3, where oxygen uptake was measured over 100 hours. 

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