Carbon content, aliphatic

The other two parameters can be evaluated from complementary use of the C13 and proton data. In order to calculate these precisely, one needs to know the number of aliphatic carbons located to aromatic rings and the number of those further removed. Unfortunately, as pointed out before, there is considerable overlap between these signals the best one can do is to evaluate the total aliphatic carbon content, By complementing the C13 data... 

Figure 11. Plot of oil yields of shales vs. aliphatic carbon content determined by C CP/MAS NMR spectra. Key O, kerogen concentrate and , raw oil shale. (Reproduced, with permission, from Ref. 18a. Copyright 1979, IPC Bus Press.)...

The C - NMR spectrum of this material (Figure 3) shows significant presence of substituted aromatic material (125 ppm) as well as aliphatic carbon content. This spectrum shows a considerably reduced presence of polysaccharide decomposition products compared to fulvic acid extracted from wastewater (11). The % -NMR spectrum (Figure 4) also indicates significant presence of substituted aromatic compounds (ca. 7 ppm). 

There is a clear trend, however, in the content of aromatic carbon in a coal and its convertibility at short times. This is shown in Figure 13. It can be seen that high convertibility occurs for coals which are intermediate in aromatic carbon content. This observation is consistent with the common belief that thermal fragmentation occurs at aliphatic positions a or to aromatic rings. 

Recent investigations have indicated that the aliphatic carbon fraction, rather than aromatic fraction, was strongly correlated to HOC sorption. For instance, the sorption of phenanthrene was related to nonpolar aliphatic carbon fraction, excluding poly(methylene), but was very strongly correlated with the content of the amorphous nonpolar aliphatic domains including amorphous poly(methylene) (Mao et al. 2002). In other words, the rubbeiy, relatively low-density, and amorphous nonpolar aliphatic carbon domains are excellent for phenanthrene partitioning (Figs. 3 and 4). 

A sorption isotherm is completed for each solid particle type and SWMs/ COMs. A range of solid to solution concentrations (i.e., solid solution) was chosen for each solid phase and waste material leachate (e.g., 50-250 mg/l),with about five data points per range. All control and test samples were performed in duplicate. The solution used in the isotherms was prepared by a 24-h batch leaching experiment with the solid test material and distilled water. The material controls consisted of the test material leachate without the solid phase particles. Chemical analyses, expressed either as TOC or as individual organic compound (e.g., aliphatic and aromatic compounds) concentrations relative to the organic carbon content of the SWM/COM, revealed the actual concentrations of various organic constituents in the leachates. Solid phase controls were also prepared for each of the test soils/sediments in order to determine the concentrations of the constituents leached from the solid phase alone. 

See Flashless Cordites in Vol 3, p C522-R Refs 1) F. R. Benson, PATR 1174 (June 1942) (Aliphatic nitramines of low carbon content)... 

Various methods and assumptions give for a vitrinite of 84% C content, values of aromaticity, / , ranging from 0.64 to 0.81 (3). A number of arguments suggest that H.i/C.t should be at least 1.65, which raises the minimum value for / to 0.71. For various reasons (4) we believe 0.77 is the most probable value, which would mean that C.i/C is 0.23. Certainly not all aliphatic carbon is alicyclic, so that C.nc7ci/C must be smaller than C.i/C. Hence we feel that the data of Peover in the above table are unrealistic, but all the other values (including the revised figures of Mazumdar et al. but not... 

It had been observed earlier (J7, J8, 19) that in coals of 80-90% carbon content (on dmf basis) the sum of aromatic and hydroaromatic fractions appears always to be almost constant at 92 2% of the total carbon in coal. The balance of 6-10% could thus be aliphatic carbon. The accuracy of such an estimate obviously would depend upon the accuracy of the aromaticity and hydroaromaticity values. The conclusion that the sum of aromatic and hydroaromatic carbon fractions is nearly constant at the region of 92-93% of the total carbon has also emerged from the recent deductions made by A. F. Gaines (11) and the authors (20) by interpreting infrared and NMR data. 

The technique for estimating the total aliphatic carbon (especially methyl carbon) in coal may require further refinements. However, in view of the foregoing discussions on the self-consistency of the estimated methyl content with other forms of carbon in coal, it seems unlikely that there are side chains longer than methyl group in normal coals. 

Methods of Structural Analysis. The most significant differences between structural models 1 and 2 are the prominent aromatic carbon content in model 1 and the aliphatic alicyclic ring content in model 2. Determinations of aromatic carbon content and ring content of fulvic acid might be useful for identifying sources and processes of degradation and fractionation. However, neither of these procedures is simple and straightforward. 

H NMR data from these seven sites are presented by spectral peak-height ratios in Table III. The sites were listed in order of increasing aromatic plus olefinic carbon percentages. Fulvic acids from all the lake samples are much lower in aromatic plus oleflnic carbon content than those from river samples. These results confirm the hypothesis that autothonous inputs result in dissolved humic substances that have a low aromatic plus oleflnic carbon content. The lake samples also are lower in the ratios of peak 2 (carboxylated chains and aliphatic ketones), peak 3 (carbohydrates), and peak 4 (phenolic tannins and lignins) to peak 1 (branched methyl groups and alicyclic ali-phatics) than are the river samples. 

The metamorphic alteration of hydrocarbon structural units has been studied by Robin et al. (1977) 21), who documented the expected disappearance of aliphatic C—H bonds with increasing levels of maturity, and also demonstrated the disappearance of aromatic C—H bonds as structures approach extreme levels of carbonization. In extreme cases when the carbon content exceeds 91 % by weight and the H/C atomic ratio is only 0.4, aliphatic and G=0 bonds have vanished, and aromatic C=C are the main components remaining in IR spectra. The... 

Some FTIR bands can be used to represent existing parameters of coalification because of their interdependent relationships. They are (a) aliphatic CH3 at 2956 cm-1 (and CH at 2891 cm-1) for calorific value and moisture content, and (b) aromatic CH at 750 cm-1 (also 884, 815, and 801 cm-1 bands and total aromatic content) for reflectance and carbon content. 

Rept 830 (1942) 3) F.R. Benson, "Study Explosive Characteristics of Aliphatic Nitramines of of Low Carbon Content , PATR 1174 (1942)... 

Victorian brown coals are thought to be largely amorphous, containing aromatic layers of single substituted benzene rings crosslinked by aliphatic chains to form a three dimensional structure. Their carbon content is quite low, varying from 60 to 70. One would therefore expect its porous system to be somewhat like that of an open structure having micropores which are randomly-oriented. In this preliminary study two samples of Yallourn ream coal were taken from the Yallourn open cut mine in the Latrobe Valley, Victoria, Australia. The samples, a pale and a medium dark lithotype, are representative of the extremes in coal types found in the Yallourn ream. 

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