Carbon-number hydrocarbons

It is likely that the spectrum of compounds produced by all Mastophora species includes a wider range of compounds than those found in this study. Several Mastophora species catch male moths that are known to respond to pheromone compounds in the even-carbon number aldehyde/ acetate/alcohol chemical class, as well as males of other species that are known to respond to pheromone compounds in the odd-carbon number hydrocarbon chemical class (9, 13). 

The other issue is the carbon number distribution of pyrolysis oil containing low carbon number hydrocarbons. This affords a relatively high yield of gasoline component. The light oil is subject to the expensive gasoline tax for external sale. 

Olefinicity of the product is pictured in the diagrams of olefin content in carbon number hydrocarbon fractions and 1-olefin content in n-olefin carbon number fractions (Fig. 4). Horizontal lines (no influence of carbon number) represent primary olefin selectivity. Then these diagrams show that with both synthesis gases, from the beginning of FT-product formation, the olefins are almost exclusively of primary nature (almost solely a-olefins). This primary olefinicity increases with time, e.g. in Fig. 4. left, from about 35 to about 80 per cent. 

There is considerably more information about nitriles from natural gas or petroleum this is to be expected since there are two distinct routes to these substances—from hydrogen cyanide and a hydrocarbon (CeHe + HCN - C H5CN -H H2) and from the pyrolysis of ammonia and hydrocarbons, particularly low-carbon number hydrocarbons, as in CHj + NH3 + CftHe - CeHfcCN 4- 4H2. The latter process is reviewed by Groggins (7), and is extended to imsaturated hydrocarbons. Both acetonitrile and acrylonitrile are so obtained industrially. 

The radioactivity per mole of hydrocarbon was essentially constant for C2 and higher hydrocarbons (Figure 8). The activity for hydrocarbons greater than C4 was not determined for individual carbon number hydrocarbons rather, the number of moles was obtained from pressure-volume measurements for the hydrocarbon and the CO2 produced by their complete combustion was used to obtain the average number of carbons per molecule. A comparison of the molar activity of the hydrocarbons to the activity in the original alcohol indicated that one molecule out of three to four contained the carbon atoms of the radioactive alcohol. Thus, the results indicated that ethanol, or a C2 species derived from it, acted as a chain initiating intermediate in the synthesis of higher hydrocarbons from a CO/H2 mixture over an iron catalyst. 

Our own results using Py-GC for more than 40 analyzed wax samples produced quite distinctive fingerprints even within the same class (for example, plant waxes). Also, as was demonstrated by the comparison of beeswax from fresh samples to some approximately 40(X) years old, the fingerprints for this material are very stable and could be easily recognized in spite of minor differences in the middle portion of the pyrogram (see Figure 6.1). Only in beeswax, in the last portion of pyrogram, which represents undecomposed hydrocarbons, can one easily spot differences in the amount of even- and odd-carbon substances (in beeswax odd carbon number hydrocarbons will always dominate). 

Reactors for Low-Temperature Operation The preceding discussion in Section 3.3.1b shows that the low-temperature mode is used for obtaining higher carbon number hydrocarbons (diesel/waxes). Sasol started this mode with five shell- and tube-type fixed beds in 1955. These reactors operated at 2.7 MPa and 230 °C, producing 21,0(X)... 

The 2n exponent in the denominator appears to be in error, since similarly derived rate expressions, listed below, have exponents of 2. Also, the 2n exponent leads to very unreasonable results for rates of reaction of higher carbon number hydrocarbons. 

Nonadecane, (Cu)) like other odd carbon number hydrocarbons C9 to C45, undergoes a sbUd - solid phase transition below its meltingpoint. For this change occurs at 22.8 °C, while melting occurs at 32 (1. The subcell pacsing of... 

The sulfides are chemically neutral they can have a linear or ring structure. For molecules of equal carbon number, their boiling points are higher than those of mercaptans they constitute the majority of sulfur containing hydrocarbons in the middie distillates (kerosene and gas oil). 

One can effectively reduce the tliree components to two with quasibinary mixtures in which the second component is a mixture of very similar higher hydrocarbons. Figure A2.5.31 shows a phase diagram [40] calculated from a generalized van der Waals equation for mixtures of ethane n = 2) with nomial hydrocarbons of different carbon number n.2 (treated as continuous). It is evident that, for some values of the parameter n, those to the left of the tricritical point at = 16.48, all that will be observed with increasing... 

The principal nonpolar-type adsorbent is activated carbon. Kquilihrium data have been reported on hydrocarbon systems, various organic compounds in water, and mixtures of organic compounds (11,15,16,46,47). With some exceptions, the least polar component of a mixture is selectively adsorbed eg, paraffins are adsorbed selectively relative to olefins of the same carbon number, but dicycUc aromatics are adsorbed selectively relative to monocyclic aromatics of the same carbon number (see Carbon, activated carbon). 

The Fischer-Tropsch process can be considered as a one-carbon polymerization reaction of a monomer derived from CO. The polymerization affords a distribution of polymer molecular weights that foUows the Anderson-Shulz-Flory model. The distribution is described by a linear relationship between the logarithm of product yield vs carbon number. The objective of much of the development work on the FT synthesis has been to circumvent the theoretical distribution so as to increase the yields of gasoline range hydrocarbons. 

SASOL. SASOL, South Africa, has constmcted a plant to recover 50,000 tons each of 1-pentene and 1-hexene by extractive distillation from Fischer-Tropsch hydrocarbons produced from coal-based synthesis gas. The company is marketing both products primarily as comonomers for LLDPE and HDPE (see Olefin polymers). Although there is still no developed market for 1-pentene in the mid-1990s, the 1-hexene market is well estabhshed. The Fischer-Tropsch technology produces a geometric carbon-number distribution of various odd and even, linear, branched, and alpha and internal olefins however, with additional investment, other odd and even carbon numbers can also be recovered. The Fischer-Tropsch plants were originally constmcted to produce gasoline and other hydrocarbon fuels to fill the lack of petroleum resources in South Africa. 

Within the VGO saturates, distribution of paraffins, isoparaffins, and naphthenes is highly dependent on the petroleum source. The naphthenes account for roughly 60% of the saturates in a normal cmde oil. However, samples can be found having paraffins from <20 to >80%. In most samples, the / -paraffins from C2Q—are still present in sufficient quantity to be detected as distinct peaks in gc analyses. Some cmde oils show a nearly symmetric pattern of peaks such that each carbon number is present in regular progression up to a maximum around C -j. Other cmde oils show a similar distribution, but have preference for odd-numbered alkanes. Both the distribution and the selectivity toward odd-numbered hydrocarbons are considered to reflect differences in petrogenesis of the cmde oils. Although / -paraffins are distinct in the gc, these usually account for only a few percent of the saturates measured by gc. 

Composition. Rosin is primarily a complex mixture of monocarboxyUc acids of alkylated hydrophenanthrene nuclei. These constituents, known as resin acids, represent about 90% of rosin. The resin acids are subdivided into two types, based on their skeletal stmcture. The abietic-type acids contain an isopropyl group pendent from the carbon numbered 13. The pimaric-type acids have a methyl and vinyl group pendent from the same carbon atom. Figure 1 shows the stmcture of typical resin acids abietic acid, C2QH2QO2 (1) is predominant. The remaining 10% of commercial rosin consists of neutral materials that are either hydrocarbons or saponifiable esters. These materials are derived from resin acids by decarboxylation or esterification. 

Development of the Nomograph. Tw o main sources of data were used to develop the nomograph McAuliffe and Price. The hydrocarbons were divided into 14 homologous series as listed in Table 1. Solubilities at 25°C were then regressed with the carbon numbers of the hydrocarbons in order to obtain the best fit for each homologous series. A second order polynomial equation fits the data very well ... 

Mineral Oil Hydraulic Fluids. No information identifying the major components of mineral oil or water-in-oil hydraulic fluids was located in the available literature, nor was any information located that described how the emulsifiers and other components in water-in-oil emulsion hydraulic fluids alter the environmental properties of the mineral oils contained in them. The carbon number range present in mineral oil hydraulic fluids probably is from C15 to C50 (IARC 1984 Shubkin 1993 Wills 1980). If automatic transmission fluids are typical of the mineral oil content in a hydraulic fluid, then mineral oil hydraulic fluids contain -90% mineral oil (Abdul et al. 1990 Papay 1989,1991). Therefore, the transport and partitioning of these hydrocarbons will largely account for the environmental behavior of mineral oil hydraulic fluids. Typical transport and partitioning information for hydrocarbons in this range is presented below this information is indicative of the transport and partitioning of mineral oils present in hydraulic fluids. 

The chromatograms of the liquid phase show the presence of smaller and larger hydrocarbons than the parent one. Nevertheless, the main products are n-alkanes and 1-alkenes with a carbon number between 3 to 9 and an equimolar distribution is obtained. The product distribution can be explained by the F-S-S mechanism. Between the peaks of these hydrocarbons, it is possible to observe numerous smaller peaks. They have been identified by mass spectrometry as X-alkenes, dienes and also cyclic compounds (saturated, partially saturated and aromatic). These secondary products start to appear at 400 °C. Of course, their quantities increase at 425 °C. As these hydrocarbons are not seen for the lower temperature, it is possible to imagine that they are secondary reaction products. The analysis of the gaseous phase shows the presence of hydrogen, light alkanes and 1-alkenes. 

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