Iron-based catalysts reaction testing

The effect of oxidation pretreatment and oxidative reaction on the graphitic structure of all CNF or CNF based catalysts has been studied by XRD and HRTEM. From the diffraction patterns as shown in Fig. 2(a), it can be observed the subsequent treatment do not affect the integrity of graphite-like structure. TEM examination on the tested K(0.5)-Fe(5)/CNF catalysts as presented in Fig.2(b), also indicates that the graphitic structure of CNF is still intact. The XRD and TEM results are in agreement with TGA profiles of fi-esh and tested catalyst there is no obviously different stability in the carbon dioxide atmosphere (profiles are not shown). Moreover, TEM image as shown in Fig. 2(b) indicates that the iron oxide particle deposited on the surface of carbon nanofibcr are mostly less than less than 10 nm. 

Tests on the activity of LP-produced Fe-based nanopowders for liquefaction of a sub-bituminous coal under high (688 K, 1 h of reaction) and low (658 K, 0.25 h of reaction) severity conditions have been reported.38 The catalysts tested were Fe7C3 (92 m2 g 1 (BET), particle size = 17 nm (XRD))and Fe XS (42 m2 g 1 (BET), particle size = 14 nm (XRD).38 For comparison, a commercial superfine iron oxide catalyst (SFIO, supplied by Mach I, Inc.) whose major phase has been identified in one study as y-Fe20339 (surface area = 195 m2 g 1 (BET), particle diameter = 3 nm (XRD)) and in other study as the ferrihydrite40 was also evaluated under similar conditions. The coal liquefaction experiments were carried out in 50 cm3 horizontal microautoclave reactors loaded with 3 g of sub bituminous Black Thunder coal and 5 g of tetralin used as hydrogen donor. Catalyst loadings of 0.7% and 1.4% of as-received coal... 

If the iron- and tin-based catalyst Indeed acts to inhibit radical propagation reactions then two major consequences of this effect can be tested in coal reactions. Firstly, and most importantly, the rate of the thermally Induced breakdown of the coal should be reduced in the initial minutes of the coal reaction. This has recently been demonstrated when iron catalysts were used in a series of short residence time studies ( v l2 minutes to temperature then autoclave quenched). The results, summarized in Table 2, show that the conversion of acid washed coal after rapid heating to 450 C had a conversion of 55% (daf coal) while the conversion of acid washed coal that had been re-exchanged with 240 mmol of iron kg (dry coal) had a conversion of only 46%. A similar trend was found for the reaction of as mined coal (39% conversion) and the same coal that had been treated with a solution of iron(II) acetate (300 mmol kg dry coal) and had a conversion of 33%. It is interesting to note that the natural Inorganics of the as-mlned coal had a very strong inherent activity to slow the rate of thermal decomposition. 

Figure 4 shows that activities of several kinds of iron oxide based catalysts. A Fe/Ca/Al oxides catalyst exhibited the best performance among the catalysts tested. Fe/Ca/Al and Fe/Al oxides catalysts were highly active, whereas Fe/Ca and Ca/Al oxides catalyst were extremely low in activity. The selectivities of Fe/Al oxides and Fe/Ca/Al oxides catalysts were almost the same (97% at 5.25 h), and the main by-products were benzene and toluene. Therefore the addition of an optimum amount of CaO to Fe/Al based catalyst could suppress the deactivation of the catalyst during long term reaction. Further experiment are under achievement to elucidate precisely the role of CaO. 

Activity and selectivity of nanosized nickel ferrites have been studied for hydrogen and syngas prodnction via the CO2 reforming of methane (DRM). The catalysts were prepared by two different methods (i) co-precipitation (CP) route using nitrates salts as precursors and (ii) hydrothermal (HT) method using chlorides as starting salts. The materials were characterized by several techniques HT-XRD, TGA-DTA, XRD, BET, LRS, TPR, SEM. Surface acid-base measurements were performed by 2-propanol decomposition (IPA) and catalysts were tested in DRM reaction. A relationship is established between the method of preparation, the solid structure, the surface acid-base properties and the catalytic activity of iron-nickel solids in DRM reaction. The surface acid-base properties seem to play an important role in DRM reaction. 

A practical method of modification of polysaccharides by clean oxidation using H2O2 as oxidant and cheap iron phthalocyanine as catalyst has been developed. Since no acids, bases or buffers and no chlorinated compounds were used, a pure product can be recovered without additional treatment. Importantly, this flexible method provides materials with a wide range of DScho and DScooh just by an appropriate choice of the reaction conditions. Oxidized polysaccharides thus obtained possess various, tailormade hydrophihc/hydrophobic properties which have been tested successfully in cosmetic and other apphcations. 

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