Hydrocarbon fraction yields

The thermionic nitrogen-phosphorus detector (NPD) was employed by Lee et al. (48), using an SE-52 SCOT column for fingerprinting used engine oils for forensic purposes. Nitromethane extracts containing the polynuclear hydrocarbon fraction yielded peak patterns with either an FID or NPD, which were characteristic for a particular engine. 

TABLE 6.17 Fractional Yields of Dicarbonyl Compounds from the OH Reaction with Some Aromatic Hydrocarbons at 1 atm Total Pressure and 298 K ... 

In any of these tests, different hydrocarbons (such as //-penlane or n-heptane) will give different yields of the asphaltene fraction, and if the presence of the solvent is not compensated by the use of additional hydrocarbon, the yield will be erroneous. In addition, if the hydrocarbon is not present in large excess, the yields of the asphaltene fraction will vary and will be erroneous (Speight, 1999). 

The rest of the cyclic terpenoid sulfides are complex mixtures of partially degraded and isomerized derivatives of the terpenoid sulfides which elute on the capillary GC column as a broad, unresolved hump. On Raney nickel reduction this fraction yields a complex mixture of naphthenic hydrocarbons which cannot be resolved further by GC analysis. 

Quantitation. Pristane and phytane concentrations (/xmol/kg bitumen) were obtained by integration of their peak areas and that of the deuterated C22 anteisoalkane (I, Table II) standard in the FID chromatograms. The concentration of the other compounds in the saturated hydrocarbon fraction were obtained by integration of appropriate peaks in mass chromatograms of m/z 57 (n-alkanes, standard), m/z 367 (extended hop-17(21)-enes), m/z 191 (hopanes), m/z 217 (steranes). Because of differences in yield of these ions for different classes of compounds the values for hop-17(21)-enes, steranes and hopanes are approximate. 

The gas chromatograms of the hydrocarbon fractions indicate that asphaltene consists of complex macromolecules that decompose to yield a wide distribution (from C10 to - Qjs) of molecules within each of the saturate, mono-, di-, and poly aromatic and polar classes. 

The cracking of PE/LCO and PP/LCO blends over HZSM-5 zeolite catalysts in the riser simulator at 450°C led towards mainly a C5-C12 hydrocarbon fraction of aromatic nature and a low yield of C1-C2 gases and coke. 

Slobodin et al. [39] confirmed that thermal decomposition of EPR (equimolar ratio) began at 170 °C and ceased at 360 C. A total 93.66% condensate products, 5.2% gas and 1.14% carbonaceous residue were obtained, mainly at 235 °C. The composition of the gaseous portion, determined by GLC was ethane-ethylene 1.25%, propane 0.81%, propylene 0.98%, butane-butylene 0.99% and butadiene 0.99% by wt. of EPR. The liquid products were separated into five fractions with boiling ranges of 100 C, 100-150 C, 150-200 °C, 200-250 °C, and >250 °C. The fractionation yielded pentane, 1-pentene, 2-methylbutane, 2-methyl-l-butene, 2-methyl-2-butene, isoprene and piperylene of C5 hydrocarbon and hexane, 1-hexane, 2-methylpentane of Cg hydrocarbons. Based on these data, the thermal degradation was proposed to proceed via a free-radical mechanism. A free radical CH3... 

The saturate and aromatic hydrocarbons were separated from the alcohols by elution chromatography on alumina deactivated with 3.8% water in a ratio of 5 g of alumina to 1 g of oil, by successive elutions with (1) 30 mL of cyclohexane and (2) 50 mL of 2% benzene in cyclohexane. The alcohols were recovered for future analysis by washing the column with 100 mL of ethyl ether. The solvent was removed from the hydrocarbon fraction and the yield of saturates plus aromatics calculated back to the neutral oil. The percentage of olefins was determined by difference. The percentage of aromatic material was determined as the difference between the saturates and aromatics from the hydroboration and the saturates from acid absorption. 

Further confirmation of the surface nature of Grignard formation is the observation that when THF-ds and diethyl ether-djo were used as solvent only 28% and 6% deuterium, respectively, were found in the hydrocarbon fraction of the reaction . The source of hydrogen atoms is the disproportionation of the surface radicals. Moreover, the yield of hydrocarbons from reaction in THF is only 1.0-1.5 % whereas in diethyl ether the yield is 20%. This is in accord with the greater solvating power of THF which removes the metal organic species from the surface of the magnesium. Recent XPS analysis of the Grignard formation reaction is consistent with the surface nature of the reaction . 

The influence of the process temperature on catalytic hydropyrolysis of biomass/plastic mixture was studied in the range 360 - 460 C. Fig. 3 shows that the highest conversion (91% wt.) of the pine wood / polyethylene mixture (1 1 weight ratio) was observed at 390 C - 430 C in the presence of activated haematite catalyst. Higher tenqieratures promote increased yields of char and gaseous products. At lower temperatures a reduced yield of distillate fraction was observed. In comparison with pyrolysis in inert atmosphere the increased yields of light hydrocarbon fractions (by 1.6 - 1.8 times) and increased degree of mixture conversion (by 1,2 time) were observed for hydropyrolysis process. 

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