Selectivity ethane

Identify ethane on the screen, and click on it (left mouse button on the PC) to make it the selected molecule. Practice rotating and translating ethane. Select a different molecule, and then rotate and translate it. 

In general, the ethylene to ethane selectivity is governed by the relative rates of the processes shown in Scheme 3.1. Here, combination of methyl radicals (step 2) is a homogeneous process, but all other steps can be both homogeneous and heterogeneous.294 It was also found that further oxidation of the C2 products (steps 4 and 6) becomes important only with increasing C2 concentration in the system.327... 

Figure 11.22 Mixed-gas ethylene/ethane selectivity of a solid polymer electrolyte membrane as a function of AgBF4 concentration in the polyamide-polyether matrix [62]...

Platinum(II), for example, K2PtClt, in an aqueous medium in the presence of 02, oxidizes ethane selectively to ethanol and ethylene glycol, whereas metallic Pt is required for the further oxidation of alcohols to carboxylic acids. Platinum metal also catalyzes the oxidation of alkenes to 1,2-diols. The presence of CO prevents further oxidation of the alcohol products.155... 

Idemitsu Kosan Co. report that the addition of alkali halides to basic oxides (such as alkaline earth oxides or lanthanide oxides) resulted in methane oxidation catalysts that produced good yields of ethylene. A LiCl/EUjOj catalyst at 750 C gave a methane conversion of 37% with an ethylene selectivity of 46% and an ethane selectivity of 4.5%. 

Hydrogenolysis reactions over Ir single crystals and supported catalysts have also been shown to be structure sensitive [M, M and M] In particular, it was found that the reactivity tracked the concentration of low-coordination surface sites. Figure A3.10.22 shows ethane selectivity (selectivity is reported here because both ethane and methane are products of butane cracking) for -butane hydrogenolysis over Ir(l 11) and the reconstructed surface Ir(l 10)-(1 x 2), as well as two supported Ir catalysts. There are clear selectivity differences between the two Ir surfaces, with Ir(l 10)-(1 x 2) having approximately three times the ethane selectivity of Ir(l 11). There is also a similarity seen between the ethane selectivity on small Ir particles and Ir (110)-(1 X 2), and between the ethane selectivity on large Ir particles and Ir(l 11). 

Figure 44 Methyl acetate conversion at 197 °C over CufSi02 catalyst doped with different metal oxides (left-hand axis) and ethane selectivity (right-hand axis) at 247 °C as a function of oxygen-metal bond strength of the promoter (normalized per...

Seauence Normalized Activities RI1/AI2O3 Rh/Ce02 Ethane Selectivity RI1/AI2O3 Rh/Cea ... 

Furthermore, the total substitution of Ni by Co in the Ni-Zn-Al catalyst leads to a diminution in ethane selectivity and an increase in the ethylene Q selectivity level in addition, the I methane selectivity increases with the time (Fig. 4). However, the total substitution of Ni by Cu leads to a diminution in the methane and ethane selectivity and an increase in ethylene selectivity although this catalyst (Cu-Zn-Al) suffers a fast deactivation (Fig 3). 

Coke formation during acetylene hydrogenation over palladium catalyst could promote hydrogen transfer to acetylene and ethylene adsorbed molecules leading to a decrease in ethane selectivity and an increase in ethylene loss. 

The reviewer of the literature faces considerable difficulties. Quite often, those studying the reactions of propane and -butane do not trouble to measure or report product selectivities, and when they are given it is most usually in graphical form, from which numbers of limited accuracy have to be extracted by tedious interpolation. Sometimes only ethane selectivities are quoted. Measurements made in UHV systems seem to be more scattered than those made in conventional equipment, and almost all values have to be converted into the Kempling-Anderson formalism (equations 13.13 and 13.14) to make them comparable. In the accompanying Tables 13.9 and 13.10, most values of F and Tj, are obtained by method (2) above. Although for n-butane products the values of 5i can easily be derived from S2 and 53,they are quoted in the tables to save the reader unnecessary labour. 

In the reaction of n-butane over (11 l)-oriented palladium-copper and -silver films,the isomerisation selectivity jumped from about 10% to much higher values (25-75%) for thebimetallics, while the ethane selectivity was lowered, but rose again for copper contents above 50%. The use of various temperatures to accommodate the activity changes complicates interpretation. Deposition of gold onto... 

IrsMo) prepared from the bimetallic carbonyl complex was somewhat more active for the -butane reaction at 488 K than a pure iridium catalyst, but high ethane selectivity was retained (1.43). The IraMoa complex gave a less active catalyst, with a lower value of S2 (1.08). The addition of zirconium to platinum (Pt7sZr25/C) lowered the rate of ethane hydrogenolysis about 20-fold, and raised the activation energy. ... 

Optimized to understand the effect of ethylene permeance and ethylene/ethane selectivity on the energy requirements of HMD configurations. 

Considerable interest has been shown in the development of synthetically useful amide manipulations. Direct allylation of amides was accomplished using palladium(O) complexes of dibenzyli-deneacetone or 1, 2-bis(diphenylphosphino )ethane. Selective IJ-... 

Interest in ethane selective oxidation to acetic acid has been rising in the last few years due to the low cost of ethane which is now easily available from the large sources of namral gas which have recently been discovered. Although different catalytic systems have been proposed, Pd-doped MoVNbO mixed oxides are one of the more promising catalysts. " ... 

Catalyst T(°C) Conversion (%) Ethane Selectivity (%) Ethane Methane... 

Vanadium-cobalt substituted aluminophosphate molecular sieve of AEI structure (VCoAPO-18) was found to be active and selective in the ODH of ethane. Its catalytic behavior can be related to the presence of redox (probably related to and Co " ") and acid sites (related to Co + cations) in addition to its unique structural properties. The conversion and ethene selectivity decreases in the order VCoAPO-18 >VO c/CoAPO-18 > CoAPO-18 [38]. At 873 K, the VCoAPO-18 catalyst showed a 50% ethene selectivity at 60% ethane conversion for an ethane/oxygen molar ratio of 4 8. Acid SAPO-34-based microporous catalysts with chabasite structure have been tested for the ODH of ethane in the temperature range of 823 to 973 K. Pure acid and La/Na containing SAPO-34 were catalytically active and a 75 ethene selectivity for 5% ethane conversion and a 60% ethane selectivity for 30% ethane conversion was observed [39]. 

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