Oxidation methane coupling

Oxidative Methane Coupling Nonporous Zr-Y-Ti-based membranes Nonporous PbO/MgO membranes... 

Oxidative methane coupling. MngCa r OjK catalyst placed in the pores of the tube. Ethylene and ethane synthesis from methane. Li/MgO (3 wt. % Li) catalyst placed in the pores of the tube. T 850 C. Conversion 30%. Selectivity to Cj products 60% T 700-750°C. Conversion 40%. Selectivity to Cj products 55%. ... 

Porous alumina tube externally coated with a MgO/PbO dense film (in double pipe configuration), tube thickness 2.5 mm, outer diameter 4 mm, mean pore diameter 50 nm, active film-coated length 30 mm. Feed enters the reactor at shell side, oxygen at tube side. Oxidative methane coupling, PbO/MgO catalyst in thin film form (see previous column). r-750X,Pr ed 1 bar. Conversion of methane <2%. Selectivity to Cj products > 97%. Omata et al. (1989). The methane conversion is not given. Reported results are calculated from permeability data. 

Table I. Oxidative Methane Coupling over Praseodymium Compounds...

The vast majority of possible applications of reactive adsorption aim at the improvement of the product yield by shifting the equilibrium in the required direction. In contrast to the nonreactive adsorption techniques, such as simulated moving beds and pressure-swing adsorption, and despite its great potential [for example, a 12-fold higher conversion per pass in oxidative methane coupling (67)], the... 

Oxidative methane coupling at high temperatures and very short residence times would hold great promise in the production of ethylene. As noted throughout, methane (natural gas) is abimdantly available at relatively low cost, albeit in remote locations, and its... 

Liu Y, Tan X and Li K (2006b), Non-oxidative methane coupling in the SrCeo.gsYbo.osOs.o (SCYb) hollow fibre membrane reactor , 7nd Eng Chem Res, 45,3782-3790. 

The basicity has been proposed to be one of the fundamental criteria for a good reactivity in oxidative methane coupling (16, 17). Two methods have recently been described (3, 5, 18) for basicity measurements. One is through benzoic add (Bronsted basidty), the other one through the adsorption and the desorption (TPD) of CO2 (Lewis basidty). The last one has been used by sending CO2 pulses on the surface at 20°C followed by TPD (see experimental). The amount of CO2 adsorbed at 20°C on the ASnOs (1) and (II) perovskites are given Table 4. 

The results obtained in the present work permit to propose that the selectivity value obtained by preparing the catalysts from chlorinated precursors can qualitatively be relat to the TPD aft CO2 adsorption. CO2 which is a poison for oxidative coupling is less adsorbed on the catalyst prepared from chlorine containing precursors. Thus chlorine is proposed to stabilize the sites which are active in oxidative methane coupling vdth respect to the poisoning by CO2. 

Zavyalova, U., Holena, M., Schlogl, R., and Baerns, M. (2011) Statistical analysis of past catalytic data on oxidative methane coupling for new insights into the composition of high-performance catalysts. ChemCatChem, 3,1935-1947. 

Prosvirin, I.P. (2014) Oxidative methane coupling over Mg, Al, Ca, Ba, Pb-promoted SrTiOs and Sr2Ti04 influence of surfece composition and microstructure. Appl. Catal. A- Gen.,... 

Moggridge, G.D., Rayment, T., and Lambert, R.M. An in situ XRD investigation of singly and doubly promoted manganese oxide methane coupling catalysts. J. Catal 1992,134, 242-252. 

Figure 5. Reaction scheme for the kinetic models on oxidative methane coupling in the gas phase applied in model A and B.

TABLE 6. Primary kinetic isotope effects for the oxidative methane coupling to carbon oxides and C2 hydrocarbons over a NaOH/CaO catalyst. 

Example 9.2-13 Catalyst design for oxidative methane coupling by using an artificial neural network and a hybrid genetic algorithm (Huang et al., 2003). 

Toniolo PS, Moya S, Schmal M. Syntheses of nanostructiued supported palladium catalysts— non-oxidative methane coupling II. Adv Chem Lett. 2013 1 1-8. 

Mostly, this energy is used in the form of heat and/or combined with electricity generation, releasing the fossil CO2 unused into the air. The oxidative methane coupling process offers the possibility of generating heat with a reduction of the release of the carbon into the atmosphere and a useful purpose for this fossil carbon (ethylene production). This makes carbon sequestration economically possible. 

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