Oxidation reactions, partial

Thus indeed CH4 oxidation in a SOFC with a Ni/YSZ anode results into partial oxidation and the production of synthesis gas, instead of generation of C02 and H20 as originally believed. The latter happens only at near-complete CH4 conversion. However the partial oxidation overall reaction (3.12) is not the result of a partial oxidation electrocatalyst but rather the result of the catalytic reactions (3.9) to (3.11) coupled with the electrocatalytic reaction (3.8). From a thermodynamic viewpoint the partial oxidation reaction (3.12) is at least as attractive as complete oxidation to C02 and H20. 

Partial oxidation reactions are usually carried out over transition metal oxides capable of changing their valent state during their interaction with reacting molecules. Naturally, zeolites with their alumina-silicate composition did not prove themselves as good oxidation catalysts. They failed also to serve as efScient catalyst supporters, since transition metals being introduced into the zeolite matrix lose their ability to activate dioxygen [3,4],... 

Single Site Catalyst for Partial Oxidation Reaction ... 

The difficulty is that characterization techniques are usually not selective towards active sites, so very often the main spectroscopic features are not evidence for active sites manifestations. However, it is possible to find some exceptions mainly among functionalized materials, such as zeolites. One of the few well established examples is TS-1 [7], a zeolite discovered in 1983 behaving as a catalyst for partial oxidation reactions in H2O2/H2O solutions [8-20]. 

Unfortunately, there is no Ti-hydroperoxo compound of known structure to be used as a model. Conversely, the structure of several Ti-peroxo complexes are known by diffraction studies [111-113], all of them showing the side on r] geometry. None of these compounds is known to be active in partial oxidation reactions [114,115]. Similar considerations can be addressed... 

Bordiga S, Damin A, Bonino F, Lamberti C (2005) Single Site Catalyst for Partial Oxidation Reaction TS-1 Case Stndy. 16 37-68 Bbttcher A, see Schmalz HG (2004) 7 157-180... 

Example 5.4.4.3b. Optimization of partial oxidation reaction by tendency modelling (after Filippi-Bossy et al. (1989))... 

There are innumerable industrially significant reactions that involve the formation of a stable intermediate product that is capable of subsequent reaction to form yet another stable product. These include condensation polymerization reactions, partial oxidation reactions, and reactions in which it is possible to effect multiple substitutions of a particular functional group on the parent species. If an intermediate is the desired product, commercial reactors should be designed to optimize the production of this species. This section is devoted to a discussion of this and related topics for reaction systems in which the reactions may be considered as sequential or consecutive in character. 

The reaction pathways for the partial oxidation reaction are still debated. According to one interpretation, CO2 and H20 are the primary products, and CO is formed by the reaction of CO2 or H20 with CH4 according to another interpretation, CO is produced directly by the reaction of CH4 with O2. 

Recently, such a temperature oscillation was also observed by Zhang et al (27,28) with nickel foils. Furthermore, Basile et al (29) used IR thermography to monitor the surface temperature of the nickel foil during the methane partial oxidation reaction by following its changes with the residence time and reactant concentration. Their results demonstrate that the surface temperature profile was strongly dependent on the catalyst composition and the tendency of nickel to be oxidized. Simulations of the kinetics (30) indicated that the effective thermal conductivity of the catalyst bed influences the hot-spot temperature. 

TPD data in Figure 1.7 show how special treatments of a V205/Ti02 catalyst can influence its properties in terms of the strength and distribution of acid sites. These treatments can be used to tune selectivity in partial oxidation reactions [59],... 

The results of a typical screening experiment for a partial oxidation reaction are shown in Figure 11.22. The patterns of the different components in the mixture correspond very well to the expected behavior. Catalysts with interesting properties can easily be identified. 

Figure 11.21 Results of high-throughput screening of catalysts in a 384-parallel single-bead reactor in a partial oxidation reaction, (a) Arrangement of inactive and total oxidation catalysts in the reactor, (b) screening results for the conversion of a hydrocarbon at 400°C, 1 mL/min per bead.

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