Hydrocarbon products, formation

Experimental temperature determination reveals little difference between the gases at 355 kHz, as is evident in Figs. 14.15a and b, similar to the results of Okitsu et al. The likely explanation for this seemingly contradictory result is that the MRR method, which requires the presence of a significant amount of hydrocarbon within the bubble core, yields a temperature value that is dictated by the hydrocarbon itself. In other words, the probe itself determines the temperature measured. This becomes apparent at higher frequency (1,056 kHz Fig. 14.15c) where it is clear that the temperature that is obtained when one extrapolates to zero hydrocarbon concentration varies depending on the probe molecule. The lower temperature for /(77-butanol is attributed to a greater rate of hydrocarbon product formation. 

Compression. Compression is the simplest and the least effective of the four recovery methods. It was the first process used for the recovery of hydrocarbon Hquids from natural gas but is used only ia isolated cases. The most significant appHcation of the compression process is for gas-cycling plants where the natural gas Hquids are removed and the remaining gas is returned to the production formation. Figure 3 is a schematic of a typical gas-cycle plant. 

Selectivity is primarily a function of temperature. The amount of by-products tends to increase as the operating temperature is raised to compensate for declining catalyst activity. By-product formation is also influenced by catalyst impurities, whether left behind during manufacture or otherwise introduced into the process. Alkaline impurities cataly2e higher alcohol production whereas acidic impurities, as well as trace iron and nickel, promote heavier hydrocarbon formation. 

It is obvious that one can use the basic ideas concerning the effect of alkali promoters on hydrogen and CO chemisorption (section 2.5.1) to explain their effect on the catalytic activity and selectivity of the CO hydrogenation reaction. For typical methanation catalysts, such as Ni, where the selectivity to CH4 can be as high as 95% or higher (at 500 to 550 K), the modification of the catalyst by alkali metals increases the rate of heavier hydrocarbon production and decreases the rate of methane formation.128 Promotion in this way makes the alkali promoted nickel surface to behave like an unpromoted iron surface for this catalytic action. The same behavior has been observed in model studies of the methanation reaction on Ni single crystals.129... 

In all experiments, unless otherwise stated, approximately 5% oxygen was added to the reaction mixture to remove free radicals from the system and thereby simplify the derivation of the modes of formation of the hydrocarbon products. 

On the other hand, the formation of ethylene was ascribed mainly to the unimolecular decomposition of a neutral excited propane molecule. These interpretations were later confirmed (4) by examining the effect of an applied electrical field on the neutral products in the radiolysis of propane. The yields of those products which were originally ascribed to ion-molecule reactions remained unchanged when the field strength was increased in the saturation current region while the yields of hydrocarbon products, which were ascribed to the decomposition of neutral excited propane molecules, increased several fold because of increased excitation by electron impact. In various recent radiolysis 14,17,18,34) and photoionization studies 26) of hydrocarbons, the origins of products from ion-molecule reactions or neutral excited molecule decompositions have been determined using the applied field technique. However, because of recent advances in vacuum ultraviolet photolysis and ion-molecule reaction kinetics, the technique used in the above studies has become somewhat superfluous. 

Mere destruction of the original hazardous material is not, however, an adequate measure of the performance of an incinerator. Products of incomplete combustion can be as toxic as, or even more toxic than, the materials from which they evolve. Indeed, highly mutagenic PAHs are readily generated along with soot in fuel-rich regions of most hydrocarbon flames. Formation of dioxins in the combustion of chlorinated hydrocarbons has also been reported. We need to understand the entire sequence of reactions involved in incineration in order to assess the effectiveness and risks of hazardous waste incineration. 

Several of these steroid derivatives underwent elimination of phosphorodichloridate anion, giving hydrocarbon products, rather than ester formation when treated with methanolic pyridine. Pyrophosphoric acid itself has been used to phosphorylate (2-hydroxymethyl)pyridine. ... 

The gases used were purchased premixed in aluminum cylinders to avoid carbonyl formation. The high purity gas mixture was further purified by a zeolite water trap and a copper carbonyl trap. The gas pressure in the reactor was measured with a capci-tance manometer and the fTow monitored with a mass fTow controT-ler. The typical gas flow rates were 15 cc/min (STP) and the maximum conversion was 1% based on integration of hydrocarbon products. The hydrocarbon products were analyzed by gas chromatography (temperature programmed chromosorb 102, FID). 

G. S. Penny. Method of increasing hydrocarbon production from subterranean formations. Patent US 4702849,1987. 

We have also observed competition between products resulting from C-C and C-H bond activation in reactions of Y with propene,138 propyne,143 2-butyric,143 four butene isomers,138 acetaldehyde,128 acetone,128 ketene,144 and two cyclohexadiene isomers,145 as well as for Zr, Nb, Mo, and Mo with 2-butyne.143 In this chapter, we use the term C-C activation to describe any reaction leading to C-C bond fission in which the hydrocarbon reactant is broken into two smaller hydrocarbon products, with one hydrocarbon bound to the metal. It is important to note, however, that C-C activation does not necessarily require true C-C insertion. As will be shown in this chapter, the reaction of Y, the simplest second-row transition metal atom, with propene leads to formation of YCH2 +C2H4. The mechanism involves addition to the C=C bond followed by H atom migration and C-C bond fission, rather than by true C-C insertion. 

Penny, G.S. "Method of Increasing Hydrocarbon Production from Subterranean Formations," US Patent 4,702,849(1987). 

Normally, only a small stoichiometric excess (2-30 mol%) of silane is necessary to obtain good preparative yields of hydrocarbon products. However, because the capture of carbocation intermediates by silanes is a bimolecular occurrence, in cases where the intermediate may rearrange or undergo other unwanted side reactions such as cationic polymerization, it is sometimes necessary to use a large excess of silane in order to force the reduction to be competitive with alternative reaction pathways. An extreme case that illustrates this is the need for eight equivalents of triethylsilane in the reduction of benzyl alcohol to produce only a 40% yield of toluene the mass of the remainder of the starting alcohol is found to be consumed in the formation of oligomers by bimolecular Friedel-Crafts-type side reactions that compete with the capture of the carbocations by the silane.129... 

Reduction of either the exo or endo isomer of 2-phenyl-2-norbornanol with trifluoroacetic acid and triethylsilane, triphenylsilane, or phenylsilane in dichloro-methane gives endo-2-phenylnorbomane quantitatively (Eq. 24).164 The stereospecific formation of only the endo-hydrocarbon can be understood on the basis that only exo approach by organosilicon hydride toward the 2-phenylnorbornyl cation intermediate is kinetically competitive for product formation.164... 

CO can be converted into either hydrocarbon products and water (via FTS) or C02 and Fl2 via the water-gas shift (WGS) reaction. The reversible WGS reaction accompanies FTS over the iron-based catalyst only at high temperature conditions. The individual rates of FTS (rFTS) and the WGS reaction (rWGS) can be calculated from experimental results as rWGS = r(,and rFTS = rco-rc02, where rCo2 is the rate of C02 formation and rco is the rate of CO conversion. 

The enthalpy change, AH, can be calculated for a steady-state process, using H°f, which is the enthalpy of formation of the various output and input components. Under the assumption that the inputs and outputs are at ambient conditions, the enthalpy of the components corresponds to the standard enthalpy of formation of each component. The kinetic and potential energy terms are neglected from the energy balance. It is also assumed that water enters the process as a liquid and hydrocarbon products leave the process as a liquid. All other components are in the gas phase. 

These observations, coupled with the findings of Muetterties et al. that none of a large number of mononuclear coordination catalysts examined showed any activity for the H2/CO reaction (53), lend further support to the idea that more than one metal center is necessary for the catalytic formation of hydrocarbon products from synthesis gas. 

No evidence of ruthenium metal formation was found in catalytic reactions until temperatures above about 265°C (at 340 atm) were reached. The presence of Ru metal in such runs could be easily characterized by its visual appearance on glass liners and by the formation of hydrocarbon products (J/1J) The actual catalyst involved in methyl and glycol acetate formation is therefore almost certainly a soluble ruthenium species. In addition, the observation of predominantly a mononuclear complex under reaction conditions in combination with a first-order reaction rate dependence on ruthenium concentration (e.g., see reactions 1 and 3 in Table I) strongly suggests that the catalytically active species is mononuclear. 

To further explore possible mechanisms of carbon-carbon bond formation, we have examined the reaction of Cp2Fe2(C0K with LiAlHi, (LAH). This reaction yields hydrocarbon products up to butane.— The results of this study are reported herein. 

Calculation of total apparent volume does not, however, take into consideration the specific yield of the formation. Specific yield is the percentage of the mobile free hydrocarbon product that will drain and be recovered under the influences of gravity. This value is dependent on flow characteristics of the hydrocarbon as well as the characteristics of the formation. Typical values may range from 5 to 20%. 

Burke, M. R. and Buzea, D. C., 1955, Unique Clean-up of Hydrocarbon Product from Low Permeability Formation Progressing in St. Paul, Minnesota Hydrological Science and Technology, Vol. 1, No. 1, pp. 53-58. 

In fluorosulfonic acid the anodic oxidation of cyclohexane in the presence of different acids (RCO2H) leads to a single product with a rearranged carbon skeleton, a 1-acyl-2-methyl-1-cyclopentene (1) in 50 to 60% yield (Eq. 2) [7, 8]. Also other alkanes have been converted at a smooth platinum anode into the corresponding a,-unsaturated ketones in 42 to 71% yield (Table 1) [8, 9]. Product formation is proposed to occur by oxidation of the hydrocarbon to a carbocation (Eq. 1 and Scheme 1) that rearranges and gets deprotonated to an alkene, which subsequently reacts with an acylium cation from the carboxylic acid to afford the a-unsaturated ketone (1) (Eq. 2) [8-10]. In the absence of acetic acid, for example, in fluorosulfonic acid/sodium... 

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