For hydrocarbon oxidation

Dunn, I. J. (1968). An interfacial kinetics model for hydrocarbons oxidation, Biotechnol. Bioeng., 11, 467—487. 

Catalyst formulations for ATR fuel processors mainly depend on the fuel and the operating temperature. ATR catalysts are required to be active simultaneously for hydrocarbon oxidation and SR reactions, be robust at high temperatures for extended periods and be resistant to sulfur poisoning and carbon deposition, especially in the catalytic zone that runs oxygen limited [33]. Moreover, they must be resistant to intermittent operation and cycles, especially in start-up and shut-down steps. 

A redox mechanism involving lattice oxygen originally proposed in 1954 by Mars and Van Krevelen (22) for hydrocarbon oxidation over V2O5 can be applied to a variety of catalytic oxidation reactions (23). The following illustrates a lattice redox mechanism for CO oxidation ... 

Role of Ciystallographic Shear Planes This area is tied to the subject of surface oxidation state. In redox kinetics it is believed that sites for hydrocarbon oxidation are different from that for reoxidation, and crystallographic shear planes (CSP) have been suggested to assist bulk oxygen movement between the sites 44,45,46,47), There have been a few studies of this phenomenon. In WO2.95 WO2.9 it has been shown CSPs are involved in oxygen transfer but... 

Table VII. Rate Constants (in Mole"1 Sec."1) for Hydrocarbon Oxidation in Absence and Presence of 0.1 to 0.4M Tetralin Hydroperoxide at 30°C.

Substituting divalent or trivalent elements for the A1 in the framework has been successfully carried out by several groups yielding novel heterogeneous catalysts (metal-substituted ALPOS, MALPOs Thomas et al 2001) for hydrocarbon oxidation and liquid phase oxidation. MALPO catalysts can be complementary to metal-doped silicalite catalysts. Particularly interesting compounds are MALPOs in which a divalent metal (Me) substitutes for the framework Al +, for example MALPO-36 (where M = Mg, Mn, Zn, Co) and MALPO-34 (M = Mg, Mn, Co etc). 

Use laminar premixed free-flame calculations with a detailed reaction mechanism for hydrocarbon oxidation (e.g., GRI-Mech (GRIM30. mec)) to estimate the lean flammability limit for this gas composition in air, assuming that the mixture is flammable if the predicted flame speed is equal to or above 5 cm/s. For comparison, the lean flammability limits for methane and ethane are fuel-air equivalence ratios of 0.46 and 0.50, respectively. 

Treatment of TPPFe(III)Cl or raeso-tetra-o-tolylporphinato-iron(III) chloride [TTPFe(III)Cl (10)] with iodosylbenzene caused rapid oxidation of the porphyrin and loss of catalytic activity for hydrocarbon oxidation. Figure 1 shows changes in the visible absorption spectrum upon treatment of 10 with iodosylbenzene. These data indicate that shortly after the addition of iodosylbenzene (Scan b, Figure 1) a new porphyrin species (11) is formed, which then rapidly decays to oxidized porphyrin products. The kinetics of this decay process are approximately first order (Figure 2). 

Oxygen difluoride (OF2) is an attractive oxidizer for many fuels (II, 16), especially hydrocarbons, because it provides the optimum O/F ratio for hydrocarbon oxidation. Since it is denser than the equimolar 02-F2 mixture (Flox), it should be easier to handle and should perform better. However, OF2 has been expensive to make because the usual preparation from F2 plus base (18) converts half the F2 to F . Consequently, the less attractive but lower cost Flox mixtures have received more attention. A better synthesis for OF2 would remove this obstacle and justify a more thorough investigation of its performance. 

An important class of oxo complexes are the titanosilicates which have properties analogous to those of the aluminosilicate clays (Section 8-7). These materials are very good catalysts for hydrocarbon oxidations in the presence of hydrogen... 

FIGURE 18. Nonsynchronous concerted mechanism for hydrocarbon oxidation. (From Newcomb et cd., 1995). 

For valency-controlled perovskite-type mixed oxides, such as Lai j Sr cCoOs, the ease with which they form oxide vacancies increases the catalytic activity for hydrocarbon oxidation. ... 

This chapter is concerned mainly with experimental observations and measurements, one purpose of which is to show how the mechanistic structures for hydrocarbon oxidation (Chapter 1) lead to the observed combustion characteristics, and to describe more recent chemical evidence from combustion studies in support of those interpretations (Section 6.5). It also paves the way to the discussion of spontaneous ignition, or autoignition, in spark-ignition engines, in Chapter 7. 

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