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ABSTRACT A naphtha derived from the liquefaction of a subbituminous (Black Thunder) or a bituminous coal (III. #6) was hydrotreated on a pilot plant scale, to provide a feedstock sufficiently low in heteroatoms for further studies in reforming. Two commercial catalysts, a Ni/Mo and a Co/Mo on alumina, were employed in the processing of the naphtha samples. The Black Thunder naphtha was processed for over 120 hours, twice using the Co/Mo catalyst and once using the Ni/Mo catalyst. For this naphtha, the removal of nitrogen was extremely difficult using the catalysts and conditions employed in this study. An average of 51.6% of the nitrogen was removed during each of the three passes. The oxygen compounds in this naphtha were relatively easily removed. During the first pass over the Co/Mo catalyst, 94.0% of the oxygen was removed.

In order to investigate the combined effect of a promoter and a detached support species on a supported metal catalyst, alkali promotion of Rh on the decorative support La[sub 2]O[sub 3] was investigated by X-ray photoelectron spectroscopy, X-ray diffraction, H[sub 2] and CO chemisorption, ethane hydrogenolysis, and cyclopropane hydrogenation. Previously, decorating lanthana moieties have been found to partially suppress ethane hydrogenolysis and cyclopropane hydrogenation on Rh/La[sub 2]O[sub 3]. The major effects of alkali promotion of Rh/La[sub 2]O[sub 3] on these reactions were a decline in apparent activation energy for ethane hydrogenolysis and a moderate additional suppression of cyclopropane hydrogenation activity. Alkali promotion of the more active Rh/SiO[sub 2] reference catalyst, which is not decorated by support entities, resulted in a much more significant suppression of these reactions. For Rh/La[sub 2]O[sub 3], alkali promotion appeared to block sites and/or pathways for hydrogen spillover. In addition, Rb inhibited the Rh-catalyzed decomposition of carbonate species on the lanthana support. No additional effect of alkali promotion was indicated on the [minus]1-eV shift of Rh 3d[sub 5/2] binding energy observed on Rh/La[sub 2]O[sub 3] relative to Rh/SiO[sub 2]. This is consistent with the lack of a Rh 3d[sub 5/2] binding energy shift observed for Rb-promotionmore » of Rh/SiO[sub 2]. The Rb 3p[sub 3/2] binding energy was shifted to the same extent as Rh in Rb/Rh/La[sub 2]O[sub 3], suggesting that the chemical environment for Rb differs between SiO[sub 2]-supported and La[sub 2]O[sub 3]-supported systems or, more likely, that the binding energy shifts observed for this system are just due to differences in the binding energies for the reference carbon on SiO[sub 2] vs on La[sub 2]O[sub 3]. 44 refs., 4 figs., 7 tabs.« less

The present study has shown that activation of a high surface area Fe2O3 catalyst in CO in a CSTR using tetralin as solvent results in an activity that is three times that of the material that is activated in H2 or directly in the syngas. Independent of the catalyst activation, similar methane and CO2 selectivities are obtained. This suggests that the active catalytic phase is the same for the three pretreatments. Since the particle size estimated by XRD shows a variation within 30%, the difference among the activities of the differently activated catalysts can be attributed to differences in the concentration of active sites on the catalyst surface rather than the extent of the surface.

Mossbauer spectroscopy indicates that a 24 hour pretreatment in CO at 260°C and 8 atm. in a tetralin solvent almost completely converts ultrafrne iron oxide (about 3 nm) to iron carbide. However, pretreatment in hydrogen under the same conditions resulted in reduction of about 33% of the iron to metallic Fe; the remainder was Fe3O4Exposure of the CO pretreated catalyst to a 1:1 H2/CO synthesis gas resulted in the gradual reoxidation of the carbides to Fe304During the first 2 hours of exposure of the H2 pretreated sample to synthesis gas, the metallic Fe was converted to iron carbides. Further exposure of the H2 pretreatment sample to synthesis gas did not result in a composition change of the catalyst. Therefore, it is concluded that iron carbides with different oxidation characteristics were formed in these two cases.

n-Propylene cyclopentane or n-propylcyclopentane labeled in the ring with {sup 14}C was converted together with n-octane using a Pt-KL zeolite catalyst operating at 482 C and ca. 14 bar. The products indicate that hydrogenolysis to produce isooctanes, not ring expansion to produce aromatics, is the major reaction pathway for the alkyl cyclopentane compound. Dilution of the {sup 14}C activity in n-propylcyclopentane during the conversion shows that C{sub 5} as well as C{sub 6} cyclization occurs during the conversion of n-octane. The current data were obtained with a catalyst that has a Pt crystal size range that is similar to those reported earlier. Furthermore, the conversion data for n-octane and n-propylcyclopentane using the Pt-KL zeolite catalyst are very similar to data obtained with catalysts based on other nonacidic supports where the Pt crystals cannot be located in a zeolite type channel. Thus, for n-octane conversion, it appears that the Pt in L zeolite catalysts has selectivities that are similar to Pt on other nonacidic supports.

Hydrogenolysis of a high carbon number alkane, octacosane, does not occur to a significant extent either under Fischer-Tropsch Synthesis (FTS) conditions nor under a 8 atm hydrogen (1 atm=1.01325 × 10 5 Pa) at 262°C using a carbided doubly-promoted fused-iron catalyst manufactured by United Catalyst, Inc. (C-73). Thus, the data show that the higher carbon number alkanes used in continuous stirred tank reactor studies do not undergo hydrogenolysis at a significant rate in comparison to the rate of hydrocarbon synthesis. This finding suggests that the two or more alphas needed for the Anderson-Schulz-Flory (ASF) plot for promoted iron FTS catalysts cannot be explained by the hydrogenolysis of higher hydrocarbons.

Ru methanation catalysts derived from oxidation of Ru{sub x}Th{sub y} intermetallics were characterized by X-ray photoelectron spectroscopy (ESCA), ion scattering spectroscopy (ISS), X-ray diffraction (XRD), BET surface area measurements, chemisorption, and gravimetric analysis. XRD measurements and gravimetric analysis indicated that all intermetallics were extensively decomposed by oxidation in air at 350{degree}C. ESCA and ISS Ru/Th intensity ratio measurements showed that surface segregation of ThO{sub 2} occurred for all catalysts. The structure of the intermetallic-derived (IM) catalysts can best be described as Ru particles embedded in a ThO{sub 2}-rich overlayer. Comparison of hydrogen and CO uptake with N{sub 2} BET surface area suggests that CO more accurately titrates surface Ru than does hydrogen. Extensive spillover of hydrogen from Ru to ThO{sub 2} was also observed for all IM catalysts. On the basis of CO chemisorption, the CO hydrogenation turnover frequency was comparable for all the IM catalysts.

A modified scheme in probabilistic packet marking (PPM) for IP traceback against distributed denial-ofservice attack is presented. This method, ID-based PPM, is proposed to improve the original PPM’s complexity of fragments combination through clustering these fragments in advance. Furthermore, by reducing the time of fragments combination, the attacking path reconstruction and attack response time can also be speeded up.