Ethylene ethane formation from

Table I presents results for six comparable pyrolysis runs made by using five laboratory reactors all runs were made with approximately 50% steam as diluent in the ethane feed. Conversions at the exit end of the reactor varied from 59% to 65%. Also, results reported for a commercial unit (11) are shown. Ethylene yields varied from about 78% to 89% in all cases except for run D44 made in the stainless steel 304 reactor. In that run, the ethylene yields were very low but production of CO, GOo, and net coke were much higher. Ethylene yields were highest in the run made in the Vycor glass reactor. In this run, coke formation was least of all runs, and no CO or C02 was detected in the product stream.

Some experiments have been carried out with ethylene-ethane mixtures as well. The data given in Table VII show the expected trend, in that with increasing ethane pressure, at a fixed ethylene concentration, the ethyl mercaptan yield increases at the expense of the yields of vinyl mercaptan and episulfide. However, while vinyl mercaptan formation seems to be completely suppressible with increasing ethane pressure, this is not the case with the episulfide. This seems clearly to be due to the fact that the two mercaptans form in competing reactions for S( Z)) atoms, while episulfide can form from ( P) atoms, arising by the collisionally induced S( Z>) - S( P) transition. 

The rate at which S( Z)) atoms react with ethylene, ethane, and COS are all of the same order of magnitude. Thus some approximate preliminary relative rate constant values are ethyl mercaptan formation 1.0 vinyl mercaptan formation 0.80 abstraction from COS, 2.0 deactivation by CO2, 0.4 and deactivation by COS, 0.06. In addition, preliminary data seem to indicate that the reactivity of sulfur atoms, formed in the photolysis of COS, increases with increasing alkyl substitution on the doubly bonded carbon atoms. However, these rate studies have proven to be more complex than anticipated in that there is an apparent pressure effect on the rate constant values. 

The products of the sensitized radiolysis are hydrogen, ethane, ethylene, propane, iso- and n-butane. Isotopic analysis has shown that ethane comes from methylene insertion. The source of ethylene is not entirely understood and may arise from either CH insertion or ion-molecule reactions. The hydrogen formed in the radiolysis of CH4-CD4 mixtures contains HD as well as Dj and Hj. The mechanism of hydrogen formation is not yet established. 

In the first stage of this reaction, butane is converted to butenes and hydrogen, propylene and methane, and ethylene and ethane. In these primary products, methane and ethane are difficult to convert further. Therefore, for a high selectivity for aromatics formation, it is desirable for the primary reaction to be only the dehydrogenation of butane to produce butene and hydrogen. Figure 7 shows the effect of contact time (W/ F) over Ga(Imp)Cu(Ex)(66 %) catalyst. At a short contact time, the main product was butenes. Therefore, on this catalyst selectivity for aromatics formation from butane is high. 

A scheme for bicyclic dimer formation from HMCTSN under plasma conditions has been proposed in our previous paper (J.) According to this scheme, formation of new Si-N bonds with tertiary nitrogen between trisilazane rings leads to crosslinking of the polymer, and involves the production of hydrocarbons such as methane and ethane. Indeed, gas chromatographic analysis of the gaseous residue after plasma polymerization has shown that it consists mainly of three hydrocarbons methane, ethane and ethylene in the 5 33 4 ratio. 

In the present macro-scale experiments the filaments have been formed following reaction of ethane with iron and iron oxides. The decomposition of ethane to elemental carbon and hydrogen is endothermic (27) and so, at first sight, it appears that the experimental results are in conflict with the above mechanism of filament growth. However, earlier work (28) has shown that the majority of carbon formed from ethane arises from the decomposition product ethylene. The latter decomposes exothermically (27) (- A H for C2H4 at 725°C is 9.2 kcal. mole- ) so that this mechanism is not contravened. A similar rationale was used by Keep, Baker and France (29) to account for the formation of carbon filaments during the nickel catalyzed decomposition of propane. 

The products of the reaction were ethylene and ethane. In the case of Ni, formation of n-butane was also observed in the late stages of the reaction. The reaction pathway to ethane was established by making additions of [14-C]ethylene to reaction mixtures. The results showed that, with each catalyst, the yield of ethane from the further hydrogenation of ethylene is small the major route to ethane formation is by direct hydrogenation of acetylene. Thus, it was concluded that the origins of the selectivity in the reaction, are to be found in the ability or otherwise of the metal, or the metal/C/H system, to catalyse the direct hydrogenation of acetylene to ethane. Similar conclusions have been reached by Guczi et in studies... 

Ethylene hydrogenation was studied at 395 K and 1 atm in order to clarify the effect of phosphine groups on the overall activity of the catalyst [222]. The hydrogenation rate (r), expressed in moles of ethane per hour per g-atom of metal, is presented in Table 23. The reproducibility and activity of these catalysts is illustrated by the fact that the values of r obtained for freshly prepared Rh-9, and the same material used two weeks and six months later were 0.31, 0.30 and 0.33, respectively. The rate of ethane formation is described by the conventional empirical equation, r = Ar-P hyiene (where x and y are exponential values characterizing reaction orders for ethylene and hydrogen). From Table 23 it follows that for almost all the catalysts x and y values are within the ranges of 0.0-0.05 and 0.9-1.0, respectively. 

For the formation of ethanethiol and diethylsulphide from ethanol, hydrogen and gaseous sulphur the reaction mixture is assumed to contain the initial constituents as well as ethanethiol, diethylsulphide, hydrogen sulphide, diethylether, acetaldehyde, ethylene, ethane and water. The results of calculating the equimolar composition of the initial mixture (C2H50H H2 S2(g) = 1 1 i) at 80 atm pressure are also included in Tabic 5 for the above three types of mixtures (i-i, i-r, r-r) in the form of numbers of moles of individual constituents at the respective temperatures. 

To describe the kinetics of the OCM reaction quantitatively, rate equations for the primary reaction steps i.e., the formation of CO and of ethane plus ethylene were determined (these two hydrocarbons were lumped since ethylene is formed from ethane only). To derive rate equations a micro-catalytic-fixed-bed reactor was operated differentially in such a way that only small conversions of the key reactants were obtained, allowing to determine reaction rates which could then be correlated with the prevailing reaction conditions (for further details see [24]). 

The major product of TCE reduction was chloromethane (CM) and no other chlorinated daughter products were observed. This is unexpected as reduction of TCE usually results in the formation of DCE isomers, which are further reduced to vinyl chloride and to ethane or ethylene 40). The pathway of CM formation from TCE reduction is unclear. Judging from the fact that CM was the only chlorinated product, we hypothesize that TCE was sorbed on the graphite surface at the cathode and both the carbon-carbon and carbon-chlorine bonds were cleaved. Additional studies are needed to determine whether carbon-carbon bond is cleaved before carbon-chlorine bond, or vise versa. 

Athene formation requires that X and Y be substituents on adjacent carbon atoms By mak mg X the reference atom and identifying the carbon attached to it as the a carbon we see that atom Y is a substituent on the p carbon Carbons succeedmgly more remote from the reference atom are designated 7 8 and so on Only p elimination reactions will be dis cussed m this chapter [Beta (p) elimination reactions are also known as i 2 eliminations ] You are already familiar with one type of p elimination having seen m Section 5 1 that ethylene and propene are prepared on an industrial scale by the high temperature dehydrogenation of ethane and propane Both reactions involve (3 elimination of H2... 

Irradiation of ethyleneimine (341,342) with light of short wavelength ia the gas phase has been carried out direcdy and with sensitization (343—349). Photolysis products found were hydrogen, nitrogen, ethylene, ammonium, saturated hydrocarbons (methane, ethane, propane, / -butane), and the dimer of the ethyleneimino radical. The nature and the amount of the reaction products is highly dependent on the conditions used. For example, the photoproducts identified ia a fast flow photoreactor iacluded hydrocyanic acid and acetonitrile (345), ia addition to those found ia a steady state system. The reaction of hydrogen radicals with ethyleneimine results ia the formation of hydrocyanic acid ia addition to methane (350). Important processes ia the photolysis of ethyleneimine are nitrene extmsion and homolysis of the N—H bond, as suggested and simulated by ab initio SCF calculations (351). The occurrence of ethyleneimine as an iatermediate ia the photolytic formation of hydrocyanic acid from acetylene and ammonia ia the atmosphere of the planet Jupiter has been postulated (352), but is disputed (353). 

Oxychlorination reactor feed purity can also contribute to by-product formation, although the problem usually is only with low levels of acetylene which are normally present in HCl from the EDC cracking process. Since any acetylene fed to the oxychlorination reactor will be converted to highly chlorinated C2 by-products, selective hydrogenation of this acetylene to ethylene and ethane is widely used as a preventive measure (78,98—102). 

A mixture of 12.6 g of benzoyl chloride in 100 cc of ethylene chloride is added dropwise to a suspension of 25.6 g of 3ethylene chloride and 21.8 g of triethylamine within 18 minutes at room temperature while stirring. The mixture is stirred at room temperature for a further 14 hours, 200 cc of water are added, the organic phase is separated and concentrated to an oil in a vacuum. Upon adding ether/dimethoxy ethane to this oil, crude 6-ben zoy I-3absolute ethanol with the addition of a small amount of coal, the compound has a melting point of 125°C to 127°C (decomp.). Displacement of the halogen with hydrazine leads to the formation of endralazine. 

A preparation of the third nitrogenase from A. vinelandii, isolated from a molybdenum-tolerant strain but lacking the structural genes for the molybdenum and vanadium nitrogenases, was discovered to contain FeMoco 194). The 8 subunit encoded by anfG was identified in this preparation, which contained 24 Fe atoms and 1 Mo atom per mol. EPR spectroscopy and extraction of the cofactor identified it as FeMoco. The hybrid enzyme could reduce N2 to ammonia and reduced acetylene to ethylene and ethane. The rate of formation of ethane was nonlinear and the ethane ethylene ratio was strongly dependent on the ratio of nitrogenase components. 

We may use the reaction mechanism for the formation of ethylene from ethane (CjHg - C2H4 + H2), Section 6.1.2, to illustrate various types of steps in a typical chain reaction ... 

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