Structural group analysis

Stenzel H, Rodicker H. 1991. Results of substance groups and structural groups analysis of petroleum fractions and their application in estimating the correlation for predicting properties. Chemische Technik 43 344-346. 

Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method. ASTM D3238-95 (2005). 

The various physical constants and functions are used for the identification of complex mixtures such as mineral oils, fatty oils, plastics, resins and silicates. Separation of these products into individual components is generally impossible, and methods had to be developed in which certain structural groupings of the mixtures are considered instead of individual molecules or atoms.To identify such complicated mixtures physical constants could be applied successfully for their structural group analysis and for the prediction of various important technical properties. 

Fractions as Determined by Structural-Group Analysis Methods, Athabasca Oil Sands A Collection of Papers Presented to K. A. Clark on His 75th Birthday, Research Council of Alberta, Alberta, Canada, 1963. 

Nowhere is the contribution of spectroscopic studies more emphatic than in application to the delineation of structural types in the heavier feedstocks. This has been necessary because of the unknown nature of these feedstocks by refiners. One particular example is the n.d.M. method (ASTM D-3238) which is designed for the carbon distribution and structural group analysis of petroleum oils. Later investigators have taken structural group analysis several steps further than the n.d.M. method. 

Leendertse, J. J., et al.. Petroleum Refiner, in press. Structural Group Analysis of Petroleum... 

From the results of IR and NMR spectroscopic measurements in combination with the element analysis and the determination of the mean relative particle mass, statistical information concerning the structural composition may be derived according to Oelert [4-11]. These calculations supply much more information than the results of the ndM-method. The results of the structural group analysis of the samples are given in Tables 4-11 to 4-13. 

Table 4-29 Correlation of thermoanalytical index numbers with values of the structural groups analysis...

Data from colloid analysis show that the concentration of the dispersion medium may be related to the distillable fraction AG400, whereas the concentration of asphaltenes, or the total of asphaltenes and petroleum resins, determines the quantity of coke residue after pyrolysis. That portion of the sample which can be cracked, CR, will usually be determined from die concentration of petroleum resins. The aliphatic side chains of the alkylaromatic system of the asphaltenes have a small influence. The coke residue can be related to the data from structural group analysis which describe the aromatic character of the samples. 

The reaction kinetic constants activation energy E and frequency factor A, can only be correlated with the concentration of paraffinic carbon, CP (from structural group analysis) with the concentration of dispersion medium (fiom colloid analysis) and with the H/C ratio (from elemental analysis). These functions show correlation coefficients of an acceptable magnitude. Examination of the correlation of the concentration of maltenes revealed a similar tendency but with very low coefficients of correlation. It is well known that the dispersion medium contains the highest concentration of chemical bonds, which can be cracked under the chosen reaction conditions [4-20]. In the pyrolysis experiments from distillation residues, about 92 % of the dispersion medium was converted, whereas conversion of the petroleum resins was only 83 %, despite the fact that the kinetic coefficients are of nearly the same magnitude for the two components. 

Table 4-164 Structure Group Analysis of Vacuum Distillates. ...

Carbon distribution and ring content data are used in characterization of oils in the refin-ing/manufacturing process and can also correlate to critical performance properties (ASTM D3238 Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method). Aromatic carbon concentration in weight percent characterizes properties and toxicity of plasticizers obtained from petroleum products. 

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