Sulfur elemental analysis

Fracturing of Model Minerals. Further insight into the processes responsible for liquid SO2 fracturing of these shales is provided by the behavior of several minerals when subjected to liquid SO2. Authenic samples of calcite (crystals), dolomite (hard lumps), gypsum (hard lumps), and illite (hard lumps) were treated with liquid SO2 at 25°C for 2-5 hours after removal of the SO2, the treated minerals were heated for 2 hours at 100°C infrared spectra and sulfur analyses were then obtained. Calcite crystals developed numerous fine cracks and a fine powder flaked off. Although the powder contained no sulfur (elemental analysis) or S-0 moieties (IR spectra), the cracked crystals were shown to contain 0.18% sulfur in the form of sulfur-oxygen structures. Although these data are consisted with a 0.7% conversion via... 

The composition of the isolated copolymer was determined from (a) the nitrogen elemental analysis, and (b) the sulfur elemental analysis. Both figures were corrected for the small amount (4-12%) of water associated with the polymer. 

The chemical composition of particulate pollutants is determined in two forms specific elements, or specific compounds or ions. Knowledge of their chemical composition is useful in determining the sources of airborne particles and in understanding the fate of particles in the atmosphere. Elemental analysis yields results in terms of the individual elements present in a sample such as a given quantity of sulfur, S. From elemental analysis techniques we do not obtain direct information about the chemical form of S in a sample such as sulfate (SO/ ) or sulfide. Two nondestructive techniques used for direct elemental analysis of particulate samples are X-ray fluorescence spectroscopy (XRF) and neutron activation analysis (NAA). 

Implementation Elemental analysis shows that the organic portion of the sample is about 50% carbon, 8% hydrogen, and has no detectable nitrogen or sulfur. About 40 wt% of the sample is soluble in an organic solvent (2 1 chloroform methanol). GC analysis of the organic-soluble portion is found to be fatty acids (Fig. 21.15). 

Elemental analysis of fuel oil often plays a more major role that it may appear to do in lower-boiling products. Aromaticity (through the atomic hydrogen/carbon ratio), sulfur content, nitrogen content, oxygen content, and metals content are all important features that can influence the use of residual fuel oil. 

XPS spectra were collected for the same petroleum residua and asphaltene samples used in the XANES studies described above. For all samples the total amount of sulfur relative to carbon as measured by XPS was comparable to that determined by bulk elemental analysis. The spectra were deconvoluted by curve fitting, and the approximate quantifications thus derived are shown in Table 111. 

R values were calculated from elemental analysis for carbon, hydrogen, and chlorine. It can be seen again that temperature has a very marked effect on composition. Even at 100°, however, about 16 mol% sulfur dioxide is present. There was also produced a small quantity (1 to 10% of the amount of copolymer) of the cyclic addition product, 3-chloro-2,5-dihydrothiophene-l,1-dioxide, m.p. 99-100°. 

Krespan allowed sulfur, tetrafluoroethylene, and thiophene to react at 150° to give 13% of a compound considered to be octafluoro-octahydrothieno[2,3-h 2, 3 -d]thiophene (190) from elemental analysis, molecular weight measurements, and IR and NMR spectra. 

Elemental analysis for carbon, hydrogen, sodium, sulfur, and chloride yielded values that are in good agreement with the calculated values. 

The octadiene 2 appears pure by proton magnetic resonance and elemental analysis. A thin-layer chromatogram [silica, developed with hexane-ethyl acetate (4 1), visualized with 5% ceric ammonium nitrate in 20% sulfuric acid and heating] shows a major spot at Rf =0.4 and a very small impurity at Rf = 0.7. The trace impurity may be removed by crystallization from hexane at —78°. The checkers found that a gas chromatogram (2% Silicone 0V-17... 

Elemental Analysis. The acetone fractions were analyzed for C, H,- and N by an automatic analyzer. Sulfur and the halogens (i.e., Cl and Br) were analyzed by combustion and subsequent titration. The following standard compounds were used for quality assurance (QA) purposes acetanilide (C, H, N), sulfanilamide (S), p-chlorobenzoic acid (Cl), and p-bromobenzoic acid (Br). 

A sample of CBI ceramic aggregate was prepared for elemental analysis by initially evaporating the sample to dryness in a mixture of concentrated hydrofluoric and sulfuric acids. The residue was then dissolved in hydrochloric acid and analyzed by atomic absorption spectrometry. Table 3 presents these results, and corresponding data from TTLC analyses of unfired and fired samples of the same material. 

Important characteristics determining the quality of a feedstock are the C/H ratio as determined by elemental analysis and the BMC Index [4.7] (Bureau of Mines Correlation Index), which is calculated from the density and the mid-boiling point resp. the viscosity. Both values give some information on the aromaticity and therefore the expected yield. Further characteristics are viscosity, pourpoint, alkaline content (due to its influence on the carbon black structure), and sulfur content, which should be low because of environmental and corrosion considerations. 

Combustion (elemental) analysis of polymeric supports has mainly been used to determine the amount of halogens, nitrogen, or sulfur present in samples of cross-linked polystyrene (see, e.g., [54]). This information can be used to estimate the loading of a support, or, for example, to verify that the displacement of a halide has proceeded to completion. In solid-phase peptide synthesis, nitrogen determination has been used to estimate the loading of the first amino acid [55]. 

Sulfoxides were found in the weak bases and the neutral Lewis bases. The presence of sulfoxides in the bases is explained by their weakly basic character (21). The presence of sulfoxides in the neutral Lewis bases probably results because the sulfur-oxygen bond is extremely polar and may complex with ferric chloride. Elemental analysis of the subfractions (discussed later) suggests that the sulfoxides are concentrated by the separation scheme and are not oxidation products that occur after the separation. The totals which are in excess of 100% reflect the degree of multifunctionality as well as possible errors in VPO molecular weight. 

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