Distribution of hydrocarbons

Uneven distribution of hydrocarbon vapors and/or cooling water. 

One final note on this topic involves an examination of diploid, triploid, and tetraploid plants for their leaf exudate hydrocarbons (Seigler et al., 1975). -Alkanes having odd numbered chains from to were recorded for almost all plants collected from several sites with much more limited distribution of hydrocarbons based on and C g. The hydrocarbon data do not assist in distinguishing groups within this species. 

Bobra, A.M., Shiu, W.Y., Mackay, D. (1979) Distribution of hydrocarbons among oil, water and vapor phases during oil dispersant toxicity tests. Bull. Environ. Contam. Toxicol. 4, 297-305. 

The distribution of hydrocarbon products found with the Ir4(CO),2/ A1C13 system is unusual in that of the four hydrocarbons detected, i.e., methane, ethane, propane, and isobutane, ethane is the major product. At the initial stage of the reaction, the ethane-to-methane ratio is 10 1, decreasing to 2 1 after 0.5-3 days. The reason for this variation with reaction time is not clear, although it was felt unlikely that it resulted from ethane being cracked to methane during the course of the reaction (59). 

The product distribution frcm the Fischer-Tropsch reaction on 5 is shown in Table I. It is similar but not identical to that obtained over other cobalt catalysts (18-21,48, 49). The relatively low amount of methane production (73 mol T when compared with other metals and the abnormally low amount of ethane are typical (6). The distribution of hydrocarbons over other cobalt catalysts has been found to fit the Schulz-Flory equation [indicative of a polymerization-type process (6)]. The Schulz-Flory equation in logarithmic form is... 

The production of hydrocarbons using traditional F-T catalysts is governed by chain growth (polymerization) kinetics. The theoretical equation describing the distribution of hydrocarbon products, commonly referred to as the Anderson-Schulz-Flory (ASF) equation, is... 

The approach to calculate the van der Waals and cavity terms from the molecular surface areas can be used for the calculation of partition coefficients. The results show that for the distribution of hydrocarbons between water and n-octanol the calculated partition coefficient is linear in carbon number. Qualitatively similar data are obtained for the distribution between other solvents and water and the results can be used to predict the retention in liquid>liquid chromatography. On the other hand, if retention in RPC occurs due to reversible binding at the surface of the stationary phase, the significant parameter is not the total surface area of the eiuite but rather the net decrease in the molecular surface area of the stationary phase ligates and that of the eiuite upon binding, i.e., the contact area in the complex. 

Scheme 3 accounts for the various products formed, and it is consistent with known transformations in organometallic chemistry. In the first step, CO2 is reduced in a proton-coupled two-electron process to form adsorbed CO. That CO is an intermediate in the reduction of CO2 to hydrocarbons is supported by the following observations. (1) Reduction of CO at copper electrodes under the same conditions gives a similar distribution of hydrocarbon products. Reduction of formate, on the other hand, gave no hydrocarbon products [98, 102]. (2) CO on the electrode surface could be detected by cyclic voltammetry measurements. Fourier transform... 

Present investigation was undertaken to elucidate the relationships between the nonaethoxylated fatty alcohols with different distributions of hydrocarbon chain lengths and surface adsorption,... 

For solutions of AEg with different distributions of hydrocarbon chain lengths, the Y log C curves appear to be different than mono-component system. The surface pressure at critical micelle concentration (iTcjic) AEg with a long hydrocarbon chain (C gEg) is Increased by adding the short AEg, but the effect is not significant if the hydrocarbon chain is in a wide distribution (i.g. coconut fatty radical) (Figure 2,3,4). As for the efficiency of surface tension reduction there is a synergestic effect for the mixed... 

Table II. Distribution of Hydrocarbons Isolated from One Representative Petroleuma...

Bituminous Substances. The distribution of hydrocarbons and other bitumens in some of the Paleozoic rocks of the area is shown in Tables I and II, the latter summarized after Swain (7). The presumed saturated hydrocarbons of the Ordovician, Silurian and Lower Devonian samples are measurably less than in the Middle and Upper Devonian samples. The presumed aromatic hydrocarbons are not as well differentiated. The pyridine-plus-methanol-eluted chromatographic fractions, arbitrarily taken as asphaltic material, also appear, like the aromatic fractions, to be controlled more by local variations than by geologic age. 

Hurtt, A.C., 1978. The distribution of hydrocarbons in Narragansett Bay sediment cores. M.S. Thesis, University of Rhode Island, Kingston, RI. 

C5-l80°F Product. Table III shows the complete distribution of hydrocarbons from representative samples of Cs-l8o°F product as determined by gas chromatography for the same two catalysts. Both product samples contain about 905 paraffins and 105 cycloparaffins. The Cs-l80°F product from Catalyst G contains a trace of benzene (0.25 ) that from Catalyst B contains no detectable aromatic compound. The small difference in the total cycloparaffins content shown in Table III is probably not significant. 

The ring-number tabulations in Tables II, III, IV, and V are satisfactory for a simplified summary of composition and comparison. The typical Co-Mo or Ni-Mo catalyst commonly used for upgrading will saturate many of the multiple aromatic rings, depending upon severity and activity, but frequently not the last ring of a condensed-ring polyaromatic. Thus, the total number of rings is a measure of the complexity of the hydrocarbon structure. As noted earlier, more detailed data on the distribution of hydrocarbon types in these liquids are available when needed. 

Fig. 9. Changes in the distribution of hydrocarbons during MTO conversion catalyzed by SAPO-34 with various coke contents. T = 698 K, WHSV = 57g/(gcat h), pMeon = 7.2 kPa. Symbols , methane ethene , propene , butene X, C5 hydrocarbons, +, Cj hydrocarbons (3S).

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

Alberty, R. A., Use of an ensemble intermediate between the generalized ensemble and the isothermal-isobaric ensemble to calculate the equilibrium distribution of hydrocarbons in homologous series, J. Chem. Phys. 84,2890 (1986). 

Hunt J. M. (1961) Distribution of hydrocarbons in sedimentary rocks. Geochim. Cosmochim. Acta 22, 37-49. 

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